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Sample records for effective cross sections

  1. Krypton charge exchange cross sections for Hall effect thruster models

    SciTech Connect

    Hause, Michael L.; Prince, Benjamin D.; Bemish, Raymond J.

    2013-04-28

    Following discharge from a Hall effect thruster, charge exchange occurs between ions and un-ionized propellant atoms. The low-energy cations produced can disturb operation of onboard instrumentation or the thruster itself. Charge-exchange cross sections for both singly and doubly charged propellant atoms are required to model these interactions. While xenon is the most common propellant currently used in Hall effect thrusters, other propellants are being considered, in particular, krypton. We present here guided-ion beam measurements and comparisons to semiclassical calculations for Kr{sup +} + Kr and Kr{sup 2+} + Kr cross sections. The measurements of symmetric Kr{sup +} + Kr charge exchange are in good agreement with both the calculations including spin-orbit effects and previous measurements. For the symmetric Kr{sup 2+} + Kr reaction, we present cross section measurements for center-of-mass energies between 1 eV and 300 eV, which spans energies not previously examined experimentally. These cross section measurements compare well with a simple one-electron transfer model. Finally, cross sections for the asymmetric Kr{sup 2+} + Kr {yields} Kr{sup +} + Kr{sup +} reaction show an onset near 12 eV, reaching cross sections near constant value of 1.6 A{sup 2} with an exception near 70-80 eV.

  2. Effect of strongly coupled plasma on photoionization cross section

    NASA Astrophysics Data System (ADS)

    Das, Madhusmita

    2014-01-01

    The effect of strongly coupled plasma on the ground state photoionization cross section is studied. In the non relativistic dipole approximation, cross section is evaluated from bound-free transition matrix element. The bound and free state wave functions are obtained by solving the radial Schrodinger equation with appropriate plasma potential. We have used ion sphere potential (ISP) to incorporate the plasma effects in atomic structure calculation. This potential includes the effect of static plasma screening on nuclear charge as well as the effect of confinement due to the neighbouring ions. With ISP, the radial equation is solved using Shooting method approach for hydrogen like ions (Li+2, C+5, Al+12) and lithium like ions (C+3, O+5). The effect of strong screening and confinement is manifested as confinement resonances near the ionization threshold for both kinds of ions. The confinement resonances are very much dependent on the edge of the confining potential and die out as the plasma density is increased. Plasma effect also results in appearance of Cooper minimum in lithium like ions, which was not present in case of free lithium like ions. With increasing density the position of Cooper minimum shifts towards higher photoelectron energy. The same behaviour is also true for weakly coupled plasma where plasma effect is modelled by Debye-Huckel potential.

  3. Effect of strongly coupled plasma on photoionization cross section

    SciTech Connect

    Das, Madhusmita

    2014-01-15

    The effect of strongly coupled plasma on the ground state photoionization cross section is studied. In the non relativistic dipole approximation, cross section is evaluated from bound-free transition matrix element. The bound and free state wave functions are obtained by solving the radial Schrodinger equation with appropriate plasma potential. We have used ion sphere potential (ISP) to incorporate the plasma effects in atomic structure calculation. This potential includes the effect of static plasma screening on nuclear charge as well as the effect of confinement due to the neighbouring ions. With ISP, the radial equation is solved using Shooting method approach for hydrogen like ions (Li{sup +2}, C{sup +5}, Al{sup +12}) and lithium like ions (C{sup +3}, O{sup +5}). The effect of strong screening and confinement is manifested as confinement resonances near the ionization threshold for both kinds of ions. The confinement resonances are very much dependent on the edge of the confining potential and die out as the plasma density is increased. Plasma effect also results in appearance of Cooper minimum in lithium like ions, which was not present in case of free lithium like ions. With increasing density the position of Cooper minimum shifts towards higher photoelectron energy. The same behaviour is also true for weakly coupled plasma where plasma effect is modelled by Debye-Huckel potential.

  4. [Study for differential cross section of ring effect].

    PubMed

    Han, Dong; Chen, Liang-fu; Su, Lin; Tao, Jin-hua; Li, Shen-shen; Yu, Chao; Wang, Zi-feng

    2010-08-01

    The Ring effect is a significant limitation to the accuracy of the retrieval of trace gas constituents in atmosphere, while using satellite data with differential optical absorption spectroscopy technique. The Ring effect refers to the filling in of Fraunhofer lines, known as solar absorption lines, caused almost entirely by rotational Raman scattering. The inelastic component of the molecular scattering results in a net increase in radiance in the line because more radiation is shifted to the wavelength of an absorption line than shifted from this wavelength to other wavelengths. The rotational Raman scattering by N2 and Oz in the atmosphere is the main factor that leads to Ring effect. Basically, the Ring effect is considered as a pseudo-absorption process in retrieval of trace gas constituents in atmosphere. The solar spectrum measured by OMI/AURA is convolved with rotational Raman cross sections of N2 and O2, divided by the original solar spectrum, with a cubic polynomial subtracted off, to create differential Ring spectrum. This method has been suggested in order to obtain an effective differential Ring cross-section for the DOAS fitting process. The differential Ring spectrum could be used to improve the accuracy of the retrieval of the trace gases concentration. The results in this paper have been in basic agreement with the corresponding results calculated with RTM, and the R2 Statistic is 0. 966 3. PMID:20939324

  5. Isospin effect on probing nuclear dissipation with fission cross sections

    NASA Astrophysics Data System (ADS)

    Tian, J.; Ye, W.

    2016-08-01

    Nuclear dissipation retards fission. Using the stochastic Langevin model, we calculate the drop of fission cross section caused by friction over its standard statistical-model value, σfdrop, as a function of the presaddle friction strength for fissioning nuclei 195Bi, 202Bi, and 209Bi as well as for different angular momenta. We find that friction effects on σfdrop are substantially enhanced with increasing isospin of the Bi system and become greater with decreasing angular momentum. Our findings suggest that in experiments, to better constrain the strength of presaddle dissipation through the measurement of fission excitation functions, it is optimal to yield those compound systems with a high isospin and a low spin. Furthermore, we analyze the data of fission excitation functions of 210Po and 209Bi systems, which are populated in p +209Bi and p +208Pb reactions and which have a high isospin and a low spin, and find that Langevin calculations with a presaddle friction strength of (3-5) ×10-21 s-1 describe these experimental fission data very well.

  6. Cross-sectional study of health effects of cryolite production.

    PubMed

    Friis, H; Clausen, J; Gyntelberg, F

    1989-01-01

    A cross-sectional health study of 101 cryolite workers was performed, using spirometry and a questionnaire. Multiple regression analysis revealed a significant correlation between the index of smoking and a decrease in FEV1 (per cent). There was no significant correlation between work-related exposure and lung function. Many cryolite workers described a group of symptoms appearing after 15 to 30 min of heavy dust exposure: nausea, followed by epigastric pain with relief after spontaneous or provoked vomiting. Thirty-four (33.6 per cent) workers complained of nausea, vomiting or diarrhoea in relation to work, compared to 3.8 per cent of 1752 men participating in the Copenhagen Male Study. PMID:2622142

  7. Reducing cross-sectional data using a genetic algorithm method and effects on cross-section geometry and steady-flow profiles

    USGS Publications Warehouse

    Berenbrock, Charles E.

    2015-01-01

    The effects of reduced cross-sectional data points on steady-flow profiles were also determined. Thirty-five cross sections of the original steady-flow model of the Kootenai River were used. These two methods were tested for all cross sections with each cross section resolution reduced to 10, 20 and 30 data points, that is, six tests were completed for each of the thirty-five cross sections. Generally, differences from the original water-surface elevation were smaller as the number of data points in reduced cross sections increased, but this was not always the case, especially in the braided reach. Differences were smaller for reduced cross sections developed by the genetic algorithm method than the standard algorithm method.

  8. Effects of silicon cross section and neutron spectrum on the radial uniformity in neutron transmutation doping.

    PubMed

    Kim, Haksung; Ho Pyeon, Cheol; Lim, Jae-Yong; Misawa, Tsuyoshi

    2012-01-01

    The effects of silicon cross section and neutron spectrum on the radial uniformity of a Si-ingot are examined experimentally with various neutron spectrum conditions. For the cross section effect, the numerical results using silicon single crystal cross section reveal good agreements with experiments within relative difference of 6%, whereas the discrepancy is approximately 20% in free-gas cross section. For the neutron spectrum effect, the radial uniformity in hard neutron spectrum is found to be more flattening than that in soft spectrum. PMID:21917470

  9. Effects of cross-section on mechanical properties of Au nanowire

    NASA Astrophysics Data System (ADS)

    Vazinishayan, Ali; Yang, Shuming; Duongthipthewa, Anchalee; Wang, Yiming

    2016-02-01

    The aim of this paper is study of the effects of multiple cross-section of Au nanowire on mechanical properties. Different cross-section models of Au nanowires including circular, hexagonal, pentagonal and rectangular were simulated by finite element modeling using ABAQUS. In this study, the bending technique was applied so that both ends of the model were clamped with mid-span under loading condition. The cross-sections had the length of 400 nm and the diameter of 40 nm, except the circular cross-section while the rest of the cross-sections had an equivalent diameter. Von Misses stresses distribution were used to define the stress distribution in the cross-section under loading condition, and elastic deformation was analyzed by the beam theory. The results disclosed that the circular and the rectangular models had highest and lowest strengths against plastic deformation, respectively.

  10. Jet inclusive cross sections

    SciTech Connect

    Del Duca, V.

    1992-11-01

    Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons.

  11. Experiment to measure total cross sections, differential cross sections and polarization effects in pp elastic scattering at RHIC

    SciTech Connect

    Guryn, W.

    1995-12-31

    The author is describing an experiment to study proton-proton (pp) elastic scattering experiment at the Relativistic Heavy Ion Collider (RHIC). Using both polarized and unpolarized beams, the experiment will study pp elastic scattering from {radical}s = 60 GeV to {radical}s = 500 GeV in two kinematical regions .In the Coulomb Nuclear Interference (CNI) region, 0.0005 < {vert_bar}t{vert_bar} < 0.12 (GeV/c){sup 2}, we will measure and study the s dependence of the total and elastic cross sections, {sigma}{sub tot} and {sigma}{sub el}; the ratio of the real to the imaginary part of the forward elastic scattering amplitude, {rho}; and the nuclear slope parameter of the pp elastic scattering, b. In the medium {vert_bar}t{vert_bar}, {vert_bar}t{vert_bar} {le} 1.5 (GeV/c){sup 2}, we plan to study the evolution of the dip structure with s, as observed at ISR in the differential elastic cross section, d{sigma}{sub el}/dt, and the s and {vert_bar}t{vert_bar} dependence of b. With the polarized beams the following can be measured: the difference in the total cross sections as function of initial transverse spin stated {Delta}{sigma}{sub T}, the analyzing power, A{sub N}, and the transverse spin correlation parameter A{sub NN}. The behavior of the analyzing power A{sub N} at RHIC energies in the dip region of d{sigma}{sub el}/dt, where a pronounced structure was found at fixed-target experiments will be studied.

  12. Experiment to measure total cross sections, differential cross sections and polarization effects in pp elastic scattering at RHIC

    SciTech Connect

    Guryn, W.

    1998-02-01

    The authors are describing an experiment to study proton-proton (pp) elastic scattering experiment at the Relativistic Heavy Ion Collider (RHIC). Using both polarized and unpolarized beams, the experiment will study pp elastic scattering from {radical}s = 50 GeV to {radical}s = 500 GeV in two kinematical regions. In the Coulomb Nuclear Interference (CNI) region, 0.0005 < {vert_bar}t{vert_bar} < 0.12 (GeV/c){sup 2}, they will measure and study the s dependence of the total and elastic cross sections, {sigma}{sub tot} and {sigma}{sub el}; the ratio of the real to the imaginary part of the forward elastic scattering amplitude, {rho}; and the nuclear slope parameter of the pp elastic scattering, b. In the medium {vert_bar}t{vert_bar}-region, {vert_bar}t{vert_bar} < 1.5 (GeV/c){sup 2}, they plan to study the evolution of the dip structure with s, as observed at ISR in the differential elastic cross section, d{sigma}{sub el}/dt, and the s and {vert_bar}t{vert_bar} dependence of b. With the polarized beams the following can be measured: the difference in the total cross sections as function of initial transverse spin states {Delta}{sigma}{sub T}, the analyzing power, A{sub N}, and the transverse spin correlation parameter A{sub NN}. The behavior of the analyzing power A{sub N} at RHIC energies in the dip region of d{sigma}{sub el}/dt, where a pronounced structure was found at fixed-target experiments will be studied. The relation of pp elastic scattering to the beam polarization measurement at RHIC is also discussed.

  13. Nuclear effects in Neutrino Nuclear Cross-sections

    SciTech Connect

    Singh, S. K.; Athar, M. Sajjad

    2008-02-21

    Nuclear effects in the quasielastic and inelastic scattering of neutrinos(antineutrinos) from nuclear targets have been studied. The calculations are done in the local density approximation which take into account the effect of nucleon motion as well as renormalisation of weak transition strengths in the nuclear medium. The inelastic reaction leading to production of pions is calculated in a {delta} dominance model taking into account the renormalization of {delta} properties in the nuclear medium.

  14. Effects of Nuclear Cross Sections at Different Energies on the Radiation Hazard from Galactic Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Lin, Z. W.; Adams, J. H., Jr.

    2006-01-01

    The radiation hazard for astronauts from galactic cosmic rays is a major obstacle in long duration human space explorations. Space radiation transport codes have been developed to calculate radiation environment on missions to the Moon, Mars or beyond. We have studied how uncertainties in fragmentation cross sections at different energies affect the accuracy of predictions from such radiation transport. We find that, in deep space, cross sections between 0.3 and 0.85 GeV/u usually have the largest effect on dose-equivalent behind shielding in solar minimum GCR environments, and cross sections between 0.85 and 1.2 GeV/u have the largest effect in solar maximum GCR environments. At the International Space Station, cross sections at higher energies have the largest effect due to the geomagnetic cutoff.

  15. Cross-section Effects in the Super-Kamiokande Tau Appearance Analysis

    SciTech Connect

    Walter, Christopher

    2011-11-23

    In this talk, I explain the search for tau neutrino appearance in the atmospheric neutrino flux at Super-Kamiokande with a particular emphasis on the effect deep inelastic cross section uncertainties have on interpreting the result. In particular, I explain why the normalization of the DIS cross-section also needs to be treated as a parameter in the fit of tau normalization, and show how a neural net based on event parameters can separate various cross-section modes in the background sample.

  16. Effects of Nuclear Cross Sections at Different Energies on Space Radiation Exposure from Galactic Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Li, Zi-Wei; Adams, James H., Jr.

    2007-01-01

    Space radiation from galactic cosmic rays (GCR) is a major hazard to space crews, especially in long duration human space explorations. For this reason, they will be protected by radiation shielding that fragments the GCR heavy ions. Here we investigate how sensitive the crew's radiation exposure is to nuclear fragmentation cross sections at different energies. We find that in deep space cross sections between about 0.2 and 1.2 GeV/u have the strongest effect on dose equivalent behind shielding in solar minimum GCR environments, and cross sections between about 0.6 and 1.7 GeV/u are the most important at solar maximum'. On the other hand, at the location of the International Space Station, cross sections at_higher -energies, between about 0.6 and 1.7 GeV /u at solar minimum and between about 1.7 and 3.4 GeV/u'at,solar maximum, are the most important This is. due-to the average geomagnetic cutoff for the ISS orbit. We also show the effect of uncertainties in the fragmentation cross sections on the elemental energy spectra behind shielding. These results help to focus the studies of fragmentation cross sections on the proper energy range in order to improve our predictions of crew exposures.

  17. Validation of Cross Sections for Monte Carlo Simulation of the Photoelectric Effect

    NASA Astrophysics Data System (ADS)

    Han, Min Cheol; Kim, Han Sung; Pia, Maria Grazia; Basaglia, Tullio; Batic, Matej; Hoff, Gabriela; Kim, Chan Hyeong; Saracco, Paolo

    2016-04-01

    Several total and partial photoionization cross section calculations, based on both theoretical and empirical approaches, are quantitatively evaluated with statistical analyses using a large collection of experimental data retrieved from the literature to identify the state of the art for modeling the photoelectric effect in Monte Carlo particle transport. Some of the examined cross section models are available in general purpose Monte Carlo systems, while others have been implemented and subjected to validation tests for the first time to estimate whether they could improve the accuracy of particle transport codes. The validation process identifies Scofield's 1973 non-relativistic calculations, tabulated in the Evaluated Photon Data Library(EPDL), as the one best reproducing experimental measurements of total cross sections. Specialized total cross section models, some of which derive from more recent calculations, do not provide significant improvements. Scofield's non-relativistic calculations are not surpassed regarding the compatibility with experiment of K and L shell photoionization cross sections either, although in a few test cases Ebel's parameterization produces more accurate results close to absorption edges. Modifications to Biggs and Lighthill's parameterization implemented in Geant4 significantly reduce the accuracy of total cross sections at low energies with respect to its original formulation. The scarcity of suitable experimental data hinders a similar extensive analysis for the simulation of the photoelectron angular distribution, which is limited to a qualitative appraisal.

  18. Effects of low-energy electrons on DNA constituents: effective cross sections for condensed thymidine

    NASA Astrophysics Data System (ADS)

    Panajotovic, Radmila

    2009-05-01

    Since the first experiments of low-energy electron scattering from condensed DNA [1] have been performed, the interest in studying low-energy electron-biomolecule interactions has been increasing. Knowledge of effective cross sections for single- and double-strand breaks of DNA and for vibrational and electronic excitation of nucleic bases and nucleosides are opening the door to better understanding of effects of radiation on live tissue and possibly indicating interaction pathways leading to gene mutations and cancer. The strong variation of effective cross sections for DNA single-strand breaks with incident electron energy and the resonant enhancement at 1 eV suggested that considerable damage is inflicted by very low-energy electrons to DNA, and indicates the important role of π* shape resonances in the bond-breaking process. However, the complexity of DNA, even if studied as a short single-strand chain, imposes a need to perform measurements on its isolated constituents, such as nucleic bases and nucleosides. Thymidine is one of the most important nucleosides of DNA and an important component of antiviral compounds. In the condensed phase, thymidine's 2'-deoxyribose ring is in the pentose sugar ring form, which is a true conformation of this nucleoside in DNA. Results from High-Resolution Electron Energy Loss [2] study of monomolecular films of thymidine will be discussed and the presence of resonances in the effective cross sections at incident energy below 5 eV will be commented as a possible indication of the dissociative electron attachment. In addition, results on the resonance structures in the effective cross sections for electronic excitations for the incident electron energy from 1.5 to 12 eV will be discussed as a possible pathway for strand brakes in DNA. [4pt] [1] Boudaiffa B, Cloutier P, Hunting D, Huels M A and Sanche L 2002 Rad. Res. 157 227-234[0pt] [2] Panajotovic R, Martin F, Cloutier P, Hunting, D, and Sanche L, 2006 Rad.Res. 165 452

  19. Inverse bremsstrahlung cross section estimated within evolving plasmas using effective ion potentials

    NASA Astrophysics Data System (ADS)

    Wang, F.; Weckert, E.; Ziaja, B.

    2009-06-01

    We estimate the total cross sections for field-stimulated photoemissions and photoabsorptions by quasi-free electrons within a non-equilibrium plasma evolving from the strong coupling to the weak coupling regime. Such a transition may occur within laser-created plasmas, when the initially created plasma is cold but the heating of the plasma by the laser field is efficient. In particular, such a transition may occur within plasmas created by intense vacuum ultraviolet (VUV) radiation from a free-electron laser (FEL) as indicated by the results of the first experiments performed by Wabnitz at the FLASH facility at DESY. In order to estimate the inverse bremsstrahlung cross sections, we use point-like and effective atomic potentials. For ions modelled as point-like charges, the total cross sections are strongly affected by the changing plasma environment. The maximal change of the cross sections may be of the order of 75 at the change of the plasma parameters: inverse Debye length, κ, in the range κ = 0 - 3 Å-1 and the electron density, ρe, in the range ρe = 0.01 - 1 Å-3. These ranges correspond to the physical conditions within the plasmas created during the first cluster experiments performed at the FLASH facility at DESY. In contrast, for the effective atomic potentials the total cross sections for photoemission and photoabsorption change only by a factor of seven at most in the same plasma parameter range. Our results show that the inverse bremsstrahlung cross section estimated with the effective atomic potentials is not affected much by the plasma environment. This observation validates the estimations of the enhanced heating effect obtained by Walters, Santra and Greene. This is important as this effect may be responsible for the high-energy absorption within clusters irradiated with VUV radiation.

  20. Effects of nuclear cross sections at different energies on the radiation hazard from galactic cosmic rays.

    PubMed

    Lin, Z W; Adams, J H

    2007-03-01

    The radiation hazard for astronauts from galactic cosmic rays (GCR) is a major obstacle to long-duration human space exploration. Space radiation transport codes have been developed to calculate the radiation environment on missions to the Moon, Mars, and beyond. We have studied how uncertainties in fragmentation cross sections at different energies affect the accuracy of predictions from such radiation transport calculations. We find that, in deep space, cross sections at energies between 0.3 and 0.85 GeV/nucleon have the largest effect in solar maximum GCR environments. At the International Space Station, cross sections at higher energies have the largest effect due to the geomagnetic cutoff. PMID:17316078

  1. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory.

    PubMed

    Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D

    2016-01-14

    We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180(∘) at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X̃(2)A2, Ã(2)B1, and B̃(2)B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃(2)B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed. PMID:26772565

  2. Resonance effects in elastic cross sections for electron scattering on pyrimidine: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D.

    2016-01-01

    We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180∘ at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X˜ 2A2, A˜ 2B1, and B˜ 2B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B˜ 2B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.

  3. Energy dependence of breakup cross sections of the halo nucleus {sup 8}B and effective interactions

    SciTech Connect

    Bertulani, C.A.; Lotti, P.; Sagawa, H.

    1998-01-01

    We study the energy dependence of the cross sections for nucleon removal of {sup 8}B projectiles. It is shown that the Glauber model calculations with nucleon-nucleon t-matrix reproduce well the energy dependence of the breakup cross sections of {sup 8}B. A distorted wave Born approximation (DWBA) model for the breakup cross section is also proposed and results are compared with those of the Glauber model. We show that to obtain an agreement between the DWBA calculations, the Glauber formalism, and the experimental data, it is necessary to modify the energy behavior of the effective interaction. In particular, the breakup potential has a quite different energy dependence than the strong absorption potential. {copyright} {ital 1998} {ital The American Physical Society}

  4. Photofission and total photoabsorption cross sections in the energy range of shadowing effects

    SciTech Connect

    Deppman, A.; Silva, G.; Anefalos, S.; Hisamoto, F.H.; Duarte, S.B.; Tavares, O.A.P.

    2006-06-15

    The energy dependence of photofission cross section for heavy nuclei has recently been well described in terms of a Monte Carlo calculation at energies from the pion photoproduction threshold up to 1 GeV [see, for instance, A. Deppman et al., Phys. Rev. Lett. 87 (2001) 182701]. Recent experimental data from CLAS (CEBAF Large Angle Spectrometer) collaboration have extended the measured photofission cross section up to 3.5 GeV for actinide and preactinide nuclei. In this work we address the calculation of photoabsorption and photofission cross sections for actinide and preactinide nuclei above 1 GeV, a region where the shadowing effect plays an important role in the nuclear photoabsorption process.

  5. Use of Relativistic Effective Core Potentials in the Calculation of Electron-Impact Ionization Cross Sections

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Kim, Yong-Ki

    1999-01-01

    Based on the Binary-Encounter-Bethe (BEB) model, the advantage of using relativistic effective core potentials (RECP) in the calculation of total ionization cross sections of heavy atoms or molecules containing heavy atoms is discussed. Numerical examples for Ar, Kr, Xe, and WF6 are presented.

  6. Effect of pressure broadening on molecular absorption cross sections in exoplanetary atmospheres

    NASA Astrophysics Data System (ADS)

    Hedges, Christina; Madhusudhan, Nikku

    2016-05-01

    Spectroscopic observations of exoplanets are leading to unprecedented constraints on their atmospheric compositions. However, molecular abundances derived from spectra are degenerate with the absorption cross-sections which form critical input data in atmospheric models. Therefore, it is important to quantify the uncertainties in molecular cross-sections to reliably estimate the uncertainties in derived molecular abundances. However, converting line lists into cross-sections via line broadening involves a series of prescriptions for which the uncertainties are not well understood. We investigate and quantify the effects of various factors involved in line broadening in exoplanetary atmospheres - the profile evaluation width, pressure versus thermal broadening, broadening agent, spectral resolution and completeness of broadening parameters - on molecular absorption cross-sections. We use H2O as a case study as it has the most complete absorption line data. For low-resolution spectra (R ≲ 100) for representative temperatures and pressures (T ˜ 500-3000 K, P ≲ 1 atm) of H2-rich exoplanetary atmospheres, we find the median difference in cross-sections (δ) introduced by various aspects of pressure broadening to be ≲1 per cent. For medium resolutions (R ≲ 5000), including those attainable with James Webb Space Telescope, we find that δ can be up to 40 per cent. For high resolutions (R ˜ 105), δ can be ≳100 per cent, reaching ≳1000 per cent for low temperatures (T ≲ 500 K) and high pressures (P ≳ 1 atm). The effect is higher still for self-broadening. We generate a homogeneous data base of absorption cross-sections of molecules of relevance to exoplanetary atmospheres for which high-temperature line lists are available, particularly H2O, CO, CH4, CO2, HCN, and NH3.

  7. Absolute effective cross sections of ionization of adenine and guanine molecules by electron impact

    NASA Astrophysics Data System (ADS)

    Shafranyosh, I. I.; Svida, Yu. Yu.; Sukhoviya, M. I.; Shafranyosh, M. I.; Minaev, B. F.; Baryshnikov, G. V.; Minaeva, V. A.

    2015-10-01

    Effective cross sections of the formation of positive ions of nitrous nucleic acids of adenine and guanine are determined by the crossed electron and molecular beam method in the energy interval from the threshold to 200 eV. It is found that the maximal value of the total cross section of adenine ionization is attained at an energy of 90 eV and is equal to (2.8 ± 0.6) × 10-15 cm2. The maximal value of the total cross section of guanine ionization is equal to (3.2 ± 0.7) × 10-15 cm2 and is observed at an energy of 88 eV. The energy ionization thresholds are determined, which amount to (8.8 ± 0.2) eV for adenine and to (8.3 ± 0.2) eV for guanine. The adenine and guanine mass spectra are measured. The absolute values of partial ionization cross sections of adenine and guanine molecules are determined.

  8. Doppler broadening effect on collision cross section functions - Deconvolution of the thermal averaging

    NASA Technical Reports Server (NTRS)

    Bernstein, R. B.

    1973-01-01

    The surprising feature of the Doppler problem in threshold determination is the 'amplification effect' of the target's thermal energy spread. The small thermal energy spread of the target molecules results in a large dispersion in relative kinetic energy. The Doppler broadening effect in connection with thermal energy beam experiments is discussed, and a procedure is recommended for the deconvolution of molecular scattering cross-section functions whose dominant dependence upon relative velocity is approximately that of the standard low-energy form.

  9. Effect of interfacial interaction on the cross-sectional morphology of tobacco mosaic virus using GISAXS.

    PubMed

    Lee, Byeongdu; Lo, Chieh-Tsung; Thiyagarajan, P; Winans, Randall E; Li, Xuefa; Niu, Zhongwei; Wang, Qian

    2007-10-23

    We have investigated the effect of the interfacial interaction on the cross-sectional morphology of the tobacco mosaic virus (TMV) in solution and on two types of solid substrates, SiOx (polar) on Si(100) and polystyrene film (nonpolar) on Si(100), using small-angle X-ray scattering (SAXS) and grazing incidence small-angle X-ray scattering (GISAXS), respectively. Results reveal that the flexible chains at the outer surface of TMV either expand or contract depending on the nature of the substrate. Although the unfavorable interaction between the TMV and the PS causes a minimal effect, the stronger attractive interaction between the outer protein surface of TMV and the SiOx substrate induces pronounced deformation of its cross-sectional morphology. PMID:17894508

  10. Evaluation of safety effectiveness of multiple cross sectional features on urban arterials.

    PubMed

    Park, Juneyoung; Abdel-Aty, Mohamed

    2016-07-01

    This research evaluates the safety effectiveness of multiple roadway cross-section elements on urban arterials for different crash types and severity levels. In order to consider the nonlinearity of predictors and obtain more reliable estimates, the generalized nonlinear models (GNMs) were developed using 5-years of crash records and roadway characteristics data for urban roadways in Florida. The generalized linear models (GLMs) were also developed to compare model performance. The cross-sectional method was used to develop crash modification factors (CMFs) for various safety treatments. The results from this paper indicated that increasing lane, bike lane, median, and shoulder widths were safety effective to reduce crash frequency. In particular, the CMFs for changes in median and shoulder widths consistently decreased as their widths increased. On the other hand, the safety effects of increasing lane and bike lane widths showed nonlinear variations. It was found that crash rates decrease as the lane width increases until 12ft width and it increases as the lane width exceeds 12ft. The crash rates start to decrease again after 13ft. It was also found that crash rates decreases as the bike lane width increases until 6ft width and it increases as the bike lane width exceeds 6ft. This paper demonstrated that the GNMs clearly captured the nonlinear relationship between crashes and multiple roadway cross-sectional features, which cannot be reflected by the estimated CMFs from the GLMs. Moreover, the GNMs showed better model fitness than GLMs in general. Therefore, in order to estimate more accurate CMFs, the proposed methodology of utilizing the GNMs in the cross-sectional method is recommended over using conventional GLMs when there are nonlinear relationships between the crash rate and roadway characteristics. PMID:27110644

  11. The effect of halo nuclear density on reaction cross-section for light ion collision

    NASA Astrophysics Data System (ADS)

    Hassan, M. A. M.; Nour El-Din, M. S. M.; Ellithi, A.; Ismail, E.; Hosny, H.

    2015-08-01

    In the framework of the optical limit approximation (OLA), the reaction cross-section for halo nucleus — stable nucleus collision at intermediate energy, has been studied. The projectile nuclei are taken to be one-neutron halo (1NHP) and two-neutron halo (2NHP). The calculations are carried out for Gaussian-Gaussian (GG), Gaussian-Oscillator (GO), and Gaussian-2S (G2S) densities for each considered projectile. As a target, the stable nuclei in the range 4-28 of the mass number are used. An analytic expression of the phase shift function has been derived. The zero range approximation is considered in the calculations. Also, the in-medium effect is studied. The obtained results are analyzed and compared with the geometrical reaction cross-section and the available experimental data.

  12. Effect of light state transitions on the apparent absorption cross section of Photosystem II in Chlorella

    SciTech Connect

    Falkowski, P.G.; Fujita, Yoshihiko

    1986-01-01

    The distribution of excitation energy between photosystems may profoundly affect the quantum yield of photosynthetic oxygen evolution. Excitation energy absorbed by pigment molecules is transferred to reaction centers, where it may potentially drive a photochemical event. To balance the photochemical events in PSII with those in PSI, excitation energy may be transferred between PSII and PSI. This type of energy transfer has been inferred primarily in the steady state quantum yield of oxygen evolution and/or fluorescence with changes in excitation wavelength. These so called ''state transitions'' have been attributed to changes in either the absorption cross section of PSII or ''spillover'' of excitation energy between the two photosystems. We report here on measurements of relative absorption cross sections of PSII under state I and state II light conditions. We simultaneously followed the yields of O/sub 2/ and the change in fluorescence yields, ..delta.. phi, as a function of flash energy using single turnover xenon flashes. Our data suggest that the effective absorption cross section of PSII does not change within +- 10% under physiological conditions in unpoisoned Chlorella pyrenoidosa. 13 refs., 3 figs.

  13. Deformation effects on sub-barrier fusion cross sections in 16O+174,176Yb

    NASA Astrophysics Data System (ADS)

    Rajbongshi, Tapan; Kalita, K.; Nath, S.; Gehlot, J.; Banerjee, Tathagata; Mukul, Ish; Dubey, R.; Madhavan, N.; Lin, C. J.; Shamlath, A.; Laveen, P. V.; Shareef, M.; Kumar, Neeraj; Jisha, P.; Sharma, P.

    2016-05-01

    Background: Couplings with various reaction channels are known to enhance sub-barrier fusion cross sections by several orders in magnitude. However, a few open questions still remain. For example, the influence of higher order static deformations on sub-barrier fusion cross sections is yet to be comprehensively understood. Purpose: We study the role of hexadecapole nuclear deformation effect on sub-barrier fusion cross sections. Also, this work aims to extract hexadecapole deformation (β4) in nuclei in the lanthanide region. Method: The evaporation residue (ER) excitation functions for 16O+174,176Yb were measured at laboratory beam energies (Elab) in the range of 64.6-103.6 MeV. Measurements were carried out by employing the recoil mass spectrometer Heavy Ion Reaction Analyzer (HIRA) at IUAC, New Delhi. Fusion barrier distributions (BDs) were extracted from data. Results from the experiment were subjected to coupled-channels analysis, in which β4 was varied as a free parameter. Results: Experimental fusion cross sections at energies below the barrier expectedly showed strong enhancement compared to the predictions from the one-dimensional barrier penetration model. Data were satisfactorily reproduced after inclusion of negative β4 for both the targets in the coupled-channels calculation. Conclusions: The significant role of hexadecapole deformation was observed in the sub-barrier fusion of 16O+174,176Yb. The proposed value of β4 reproduced the measured fusion excitation function reasonably well. The BDs from these data were also extracted but no definitive conclusions could be drawn from them.

  14. Effects of projectile resonances on the total, Coulomb, and nuclear breakup cross sections in the 6Li+152Sm reaction

    NASA Astrophysics Data System (ADS)

    Mukeru, B.; Lekala, M. L.

    2016-08-01

    In this paper we analyze the effects of the projectile resonances on the total, Coulomb, and nuclear breakup cross sections as well as on the Coulomb-nuclear interferences at different arbitrary incident energies. It is found that these resonances have non-negligible effects on the total, Coulomb, and nuclear breakup cross sections. Qualitatively, they have no effects on the constructiveness or destructiveness of the Coulomb-nuclear interferences. Quantitatively, we obtained that these resonances increase by 7.38%, 7.58%, and 20.30% the integrated total, Coulomb, and nuclear breakup cross sections, respectively at Elab=35 MeV . This shows that the nuclear breakup cross sections are more affected by the effects of the projectile resonances than their total and Coulomb breakup counterparts. We also obtain that the effects of the resonances on the total, Coulomb, and nuclear breakup cross sections decrease as the incident energy increases.

  15. The correction of pebble bed reactor nodal cross sections for the effects of leakage and depletion history

    NASA Astrophysics Data System (ADS)

    Hudson, Nathanael Harrison

    An accurate and computationally fast method to generate nodal cross sections for the Pebble Bed Reactor (PBR) was presented. In this method, named Spectral History Correction (SHC), a set of fine group microscopic cross section libraries, pre-computed at specified depletion and moderation states, was coupled with the nodal nuclide densities and group bucklings to compute the new fine group spectrum for each node. The relevant fine group cross-section library was then recollapsed to the local broad group cross-section structure with this new fine group spectrum. This library set was tracked in terms of fuel isotopic densities. Fine group modulation factors (to correct the homogeneous flux for heterogeneous effects) and fission spectra were also stored with the cross section library. As the PBR simulation converges to a steady state fuel cycle, the initial nodal cross section library becomes inaccurate due to the burnup of the fuel and the neutron leakage into and out of the node. Because of the recirculation of discharged fuel pebbles with fresh fuel pebbles, a node can consist of a collection of pebbles at various burnup stages. To account for the nodal burnup, the microscopic cross sections were combined with nodal averaged atom densities to approximate the fine group macroscopic cross-sections for that node. These constructed, homogeneous macroscopic cross sections within the node were used to calculate a numerical solution for the fine group spectrum with B1 theory. This new fine spectrum was used to collapse the pre-computed microscopic cross section library to the broad group structure employed by the fuel cycle code. This SHC technique was developed and practically implemented as a subroutine within the PBR fuel cycle code PEBBED. The SHC subroutine was called to recalculate the broad group cross sections during the code convergence. The result was a fast method that compared favorably to the benchmark scheme of cross section calculation with the lattice

  16. 2p2h effects on the weak pion production cross section

    NASA Astrophysics Data System (ADS)

    Mariano, A.; Barbero, C.

    2015-05-01

    The νln → l-p QE reaction on the A-target is used as a signal event or/and to reconstruct the neutrino energy, using two-body kinematics. Competition of another processes could lead to misidentification of the arriving neutrinos, being important the fake events coming from the CC1π background. A precise knowledge of cross sections is a prerequisite in order to make simulations in event generators to substract the fake ones from the QE countings, and in this contribution we analyze the different nuclear effects on the CC1π channel. Our calculations also can be extended for the NC case.

  17. Effective absorption cross sections and photolysis rates of anthropogenic and biogenic secondary organic aerosols

    NASA Astrophysics Data System (ADS)

    Romonosky, Dian E.; Ali, Nujhat N.; Saiduddin, Mariyah N.; Wu, Michael; Lee, Hyun Ji (Julie); Aiona, Paige K.; Nizkorodov, Sergey A.

    2016-04-01

    Mass absorption coefficient (MAC) values were measured for secondary organic aerosol (SOA) samples produced by flow tube ozonolysis and smog chamber photooxidation of a wide range of volatile organic compounds (VOC), specifically: α-pinene, β-pinene, β-myrcene, d-limonene, farnesene, guaiacol, imidazole, isoprene, linalool, ocimene, p-xylene, 1-methylpyrrole, and 2-methylpyrrole. Both low-NOx and high-NOx conditions were employed during the chamber photooxidation experiments. MAC values were converted into effective molecular absorption cross sections assuming an average molecular weight of 300 g/mol for SOA compounds. The upper limits for the effective photolysis rates of SOA compounds were calculated by assuming unity photolysis quantum yields and convoluting the absorption cross sections with a time-dependent solar spectral flux. A more realistic estimate for the photolysis rates relying on the quantum yield of acetone was also obtained. The results show that condensed-phase photolysis of SOA compounds can potentially occur with effective lifetimes ranging from minutes to days, suggesting that photolysis is an efficient and largely overlooked mechanism of SOA aging.

  18. Radar cross section of insects

    NASA Astrophysics Data System (ADS)

    Riley, J. R.

    1985-02-01

    X-band measurements of radar cross section as a function of the angle between insect body axis and the plane of polarization are presented. A finding of particular interest is that in larger insects, maximum cross section occurs when the E-vector is perpendicular to the body axis. A new range of measurements on small insects (aphids, and planthoppers) is also described, and a comprehensive summary of insect cross-section data at X-band is given.

  19. Target correlation effects on neutron-nucleus total, absorption, and abrasion cross sections

    NASA Technical Reports Server (NTRS)

    Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

    1991-01-01

    Second order optical model solutions to the elastic scattering amplitude were used to evaluate total, absorption, and abrasion cross sections for neutron nucleus scattering. Improved agreement with experimental data for total and absorption cross sections is found when compared with first order (coherent approximation) solutions, especially below several hundred MeV. At higher energies, the first and second order solutions are similar. There are also large differences in abrasion cross section calculations; these differences indicate a crucial role for cluster knockout in the abrasion step.

  20. The total charm cross section

    SciTech Connect

    Vogt, R

    2007-09-14

    We assess the theoretical uncertainties on the total charm cross section. We discuss the importance of the quark mass, the scale choice and the parton densities on the estimate of the uncertainty. We conclude that the uncertainty on the total charm cross section is difficult to quantify.

  1. XCOM: Photon Cross Sections Database

    National Institute of Standards and Technology Data Gateway

    SRD 8 XCOM: Photon Cross Sections Database (Web, free access)   A web database is provided which can be used to calculate photon cross sections for scattering, photoelectric absorption and pair production, as well as total attenuation coefficients, for any element, compound or mixture (Z <= 100) at energies from 1 keV to 100 GeV.

  2. Effects of meteor head plasma distribution on radar cross sections and derived meteoroid masses

    NASA Astrophysics Data System (ADS)

    Marshall, R. A.; Close, S.; Brown, P.; Dimant, Y.

    2016-01-01

    We present calculations that relate meteor head echo radar cross sections to the meteor head plasma distribution. We use a forward model of radar scattering from meteor plasma using a finite-difference time-domain (FDTD) model of the electromagnetic wave interaction with the plasma. This model computes the meteor head RCS for a given meteor plasma distribution, specified with a peak plasma density and a characteristic size. We then relate measured RCS values to the input size and density parameters to better characterize the meteor plasma. We present simulation results that show that the RCS is directly related to the overdense meteor area; that is, the cross-section area of the meteor inside which the plasma frequency exceeds the radar frequency. This provides a direct estimate of the meteor plasma size from a given RCS measurement. Next we investigate the effect of the assumed plasma distribution. We study the RCS resulting from Gaussian, parabolic exponential and 1/r2 distributions. Comparing the different calculated RCS from these different distributions to three-frequency head echo data from the CMOR radar, we show that the 1/r2 distribution provides the best fit to the data. However, given uncertainties in the data, we cannot conclude that any distribution is the most valid. In addition, we show that the choice of distribution assumed can alter the resulting line density q by an order of magnitude for the same data.

  3. Analysis of density effects in plasmas and their influence on electron-impact cross sections

    NASA Astrophysics Data System (ADS)

    Belkhiri, M.; Poirier, M.

    2014-12-01

    Density effects in plasmas are analyzed using a Thomas-Fermi approach for free electrons. First, scaling properties are determined for the free-electron potential and density. For hydrogen-like ions, the first two terms of an analytical expansion of this potential as a function of the plasma coupling parameter are obtained. In such ions, from these properties and numerical calculations, a simple analytical fit is proposed for the plasma potential, which holds for any electron density, temperature, and atomic number, at least assuming that Maxwell-Boltzmann statistics is applicable. This allows one to analyze perturbatively the influence of the plasma potential on energies, wave functions, transition rates, and electron-impact collision rates for single-electron ions. Second, plasmas with an arbitrary charge state are considered, using a modified version of the Flexible Atomic Code (FAC) package with a plasma potential based on a Thomas-Fermi approach. Various methods for the collision cross-section calculations are reviewed. The influence of plasma density on these cross sections is analyzed in detail. Moreover, it is demonstrated that, in a given transition, the radiative and collisional-excitation rates are differently affected by the plasma density. Some analytical expressions are proposed for hydrogen-like ions in the limit where the Born or Lotz approximation applies and are compared to the numerical results from the FAC.

  4. Annular-Cross-Section CFE Chamber

    NASA Technical Reports Server (NTRS)

    Sharnez, Rizwan; Sammons, David W.

    1994-01-01

    Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.

  5. Effects of Cross-Sectional Ovalization on Springback and Strain Distribution of Circular Tubes Under Bending

    NASA Astrophysics Data System (ADS)

    Liu, Yafei; E, Daxin

    2011-12-01

    Springback and cross-sectional ovalization are two important defects in the bending formation of tubular parts. In this article, an analytic model considering ovalization is presented to calculate the springback and tangential strain in tube bending. Compared with the calculation neglecting ovalization, the proposed model could better predict the trends of springback angle over bending radius ratio and wall thickness ratio. Moreover, calculation of the tangential strain indicates that the bending deformation is more severe in the middle than at the ends of a bent tube. Through comparison of the results of this model and the calculations neglecting ovalization, it is shown that the effects of ovalization on springback are negligible only if the bending radius ratio and the wall thickness ratio are large enough. Also, the influence of ovalization differs a lot from one material to another.

  6. 2p2h effects on the weak pion production cross section

    SciTech Connect

    Mariano, A.; Barbero, C.

    2015-05-15

    The ν{sub l}n → l{sup −}p QE reaction on the A-target is used as a signal event or/and to reconstruct the neutrino energy, using two-body kinematics. Competition of another processes could lead to misidentification of the arriving neutrinos, being important the fake events coming from the CC1π background. A precise knowledge of cross sections is a prerequisite in order to make simulations in event generators to substract the fake ones from the QE countings, and in this contribution we analyze the different nuclear effects on the CC1π channel. Our calculations also can be extended for the NC case.

  7. Diaphragm opening effects on shock wave formation and acceleration in a rectangular cross section channel

    NASA Astrophysics Data System (ADS)

    Pakdaman, S. A.; Garcia, M.; Teh, E.; Lincoln, D.; Trivedi, M.; Alves, M.; Johansen, C.

    2016-03-01

    Shock wave formation and acceleration in a high-aspect ratio cross section shock tube were studied experimentally and numerically. The relative importance of geometric effects and diaphragm opening time on shock formation are assessed. The diaphragm opening time was controlled through the use of slit-type (fast opening time) and petal-type (slow opening time) diaphragms. A novel method of fabricating the petal-type diaphragms, which results in a consistent burst pressure and symmetric opening without fragmentation, is presented. High-speed schlieren photography was used to visualize the unsteady propagation of the lead shock wave and trailing gas dynamic structures. Surface-mounted pressure sensors were used to capture the spatial and temporal development of the pressure field. Unsteady Reynolds-Averaged Navier-Stokes simulation predictions using the shear-stress-transport turbulence model are compared to the experimental data. Simulation results are used to explain the presence of high-frequency pressure oscillations observed experimentally in the driver section as well as the cause of the initial acceleration and subsequent rapid decay of shock velocity measured along the top and bottom channel surfaces. A one-dimensional theoretical model predicting the effect of the finite opening time of the diaphragm on the rate of driver depressurization and shock acceleration is proposed. The model removes the large amount of empiricism that accompanies existing models published in the literature. Model accuracy is assessed through comparisons with experiments and simulations. Limitations of and potential improvements in the model are discussed.

  8. Deformation effect on total reaction cross sections for neutron-rich Ne isotopes

    SciTech Connect

    Minomo, Kosho; Sumi, Takenori; Ogata, Kazuyuki; Shimizu, Yoshifumi R.; Yahiro, Masanobu; Kimura, Masaaki

    2011-09-15

    The isotope dependence of measured reaction cross sections in the scattering of {sup 28-32}Ne isotopes from a {sup 12}C target at 240 MeV/nucleon is analyzed by the double-folding model with the Melbourne g matrix. The density of the projectile is calculated by the mean-field model with the deformed Woods-Saxon potential. The deformation is evaluated by antisymmetrized molecular dynamics. The deformation of the projectile enhances calculated reaction cross sections to the measured values.

  9. Elastic Differential Cross Sections

    NASA Technical Reports Server (NTRS)

    Werneth, Charles M.; Maung, Khin M.; Ford, William P.; Norbury, John W.; Vera, Michael D.

    2014-01-01

    The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann-Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (A less than or equal to 16) and the momentum-space optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and LS3D methods and is compared to eikonal results. It is recommended that the LS3D method be used for high energy nucleon- nucleus reactions and nucleus-nucleus reactions at all energies because of its rapid numerical convergence and stability.

  10. Cross sections at hadron colliders

    SciTech Connect

    Paige, F.E.

    1982-01-01

    The predicted cross sections are given for new Z'/sup 0/ bosons, for the Drell-Yan continuum of ..mu../sup +/..mu../sup -/ pairs, for high p/sub T/ hadron jets, for high p/sub T/ single photons, and for the associated production of heavy quarks. These processes have been selected not to cover the most interesting physics, but to provide a representative selection of cross sections for which to compare various energies and luminosities.

  11. Binary-Encounter-Bethe ionisation cross sections for simulation of DNA damage by the direct effect of ionising radiation.

    PubMed

    Plante, I; Cucinotta, F A

    2015-09-01

    DNA damage is of crucial importance in the understanding of the effects of ionising radiation. To refine existing DNA damage models, an approach using the Binary-Encounter-Bethe (BEB) cross sections was developed. The differential cross sections for ionisation of the molecular orbitals of the DNA bases, sugars and phosphates are calculated using the electron binding energy, the mean kinetic energy and the occupancy number of each orbital as parameters. The resulting cross section has an analytic form which is quite convenient to use for Monte-Carlo codes that randomly sample the energy loss occurring during an ionisation event. We also describe an algorithm to simulate the interactions of electrons with DNA in the radiation transport code RITRACKS using the integrated BEB cross section for the bases, sugar and phosphates. PMID:25870431

  12. Aerodynamic characteristics of several current helicopter tail boom cross sections including the effect of spoilers

    NASA Technical Reports Server (NTRS)

    Wilson, J. C.; Kelley, H. L.

    1986-01-01

    Aerodynamic characteristics were determined of three cylindrical shapes representative of tail boom cross sections of the U.S. Army AH-64, UH-60, and UH-1H helicopters. Forces and pressures were measured in a wind-tunnel investigation at the Langley Research Center. Data were obtained for a flow incidence range from -45 to 90 deg and a dynamic pressure range from 1.5 to 50 psf. These ranges provided data representative of full-scale Reynolds numbers and the full range of flow incidence to which these helicopter tail boom shapes would be subjected at low flight speeds. The effects of protuberances such as tail rotor drive-shaft covers and spoilers were evaluated. The data indicate that significant side loads on tail booms of helicopters can be generated and that the addition of spoilers can beneficially alter the side loads. Although an increase in vertical drag occurs, the net effect through reduction of tail rotor thrust required can be an improvement in helicopter performance.

  13. 242Amm fission cross section

    NASA Astrophysics Data System (ADS)

    Browne, J. C.; White, R. M.; Howe, R. E.; Landrum, J. H.; Dougan, R. J.; Dupzyk, R. J.

    1984-06-01

    The neutron-induced fission cross section of 242Amm has been measured over the energy region from 10-3 eV to ~20 MeV in a series of experiments utilizing a linac-produced "white" neutron source and a monoenergetic source of 14.1 MeV neutrons. The cross section was measured relative to that of 235U in the thermal (0.001 to ~3 eV) and high energy (1 keV to ~20 MeV) regions and normalized to the ENDF/B-V 235U(n,f) evaluated cross section. In the resonance energy region (0.5 eV to 10 keV) the neutron flux was measured using thin lithium glass scintillators and the relative cross section thus obtained was normalized to the thermal energy measurement. This procedure allowed a consistency check between the thermal and high energy data. The cross section data have a statistical accuracy of ~0.5% at thermal energies and in the 1-MeV energy region, and a systematic uncertainty of ~5%. We confirmed that 242Amm has the largest thermal fission cross section known with a 2200 m/sec value of 6328 b. Results of a Breit-Wigner sum-of-single-levels analysis of 48 fission resonances up to 20 eV are presented and the connection of these resonance properties to the large thermal cross section is discussed. Our measurements are compared with previously reported results.

  14. Static and dynamic deformation effects in the fusion cross section of light heavy ions at sub-barrier energies

    SciTech Connect

    Hussein, M.S.; Canto, L.F.; Donangelo, R.

    1980-02-01

    The static and dynamic deformation effects on the sub-barrier fusion cross section of light heavy ions are investigated by performing a coupled channel calculation for the system /sup 12/C+/sup 16/O. It is found that dynamic effects are negligible whereas static effects could be important, and they appear to show up partly through absorption under the barrier.

  15. Effective Potential Energies and Transport Cross Sections for Interactions of Hydrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, James R. (Technical Monitor)

    2000-01-01

    The interaction energies for N2-He and N2-H2 are calculated by accurate ab initio methods. The virial coefficient and differential scattering cross section for N2-H2 are calculated; the theoretical results are compared with experimental data. The transport collision integrals for N2-H2 and N2-N2 interactions are calculated and tabulated; the results yield transport coefficients that compare well with measured data. Transport coefficients are found to be determined accurately from the interaction energies for a specific configuration of the molecule formed from the interaction partners. Comparisons with results of measurement and accurate calculations demonstrate that the transport properties of complex molecular interactions can be determined rapidly and fairly accurately from the interaction energies of simpler system using combination rules for the short-range parameters of effective interaction energies and the coefficients for the long-range forces. The coefficients for a two-parameter temperature expansion of diffusion and viscosity are tabulated for a realistic universal potential energy that is based primarily on the results of very accurate calculations of the He-He interaction energy.

  16. A cross-sectional survey of the effect on emerging adults living with a depressed parent.

    PubMed

    Mechling, B M

    2015-10-01

    A parent who is depressed is physically present, but may be psychologically absent, or different to their children. Changes in the parent-child relationship, feelings of loss, and increased stress can occur for the child. These factors can impair psychosocial well-being throughout the child's upbringing, and the effects might impact that child the most in their transition to adulthood. The aim of this exploratory study was to examine factors experienced while growing up with a depressed parent that might contribute to the current psychosocial well-being of emerging adults (individuals between the ages of 18 and 25) using ambiguous loss theory as a theoretical lens. A cross-sectional, correlational design with multiple regression analysis was used to examine relationships between emerging adults' (n = 120) perceptions of retrospective duration and understanding of parent's depression, caregiving, stress, social support, hope, and boundary ambiguity and current psychosocial well-being. Experiencing hope, stress, and then the length of parent's depression during their upbringing were the most predictive variables for emerging adult psychosocial well-being. Findings from this study will help mental health professionals better understand factors contributing to outcomes for this population. The knowledge to be gained is important for developing or refining age and developmentally appropriate interventions aimed at improving outcomes of adult children of depressed parents. PMID:26148684

  17. Generalized warping effect in the dynamic analysis of beams of arbitrary cross section

    NASA Astrophysics Data System (ADS)

    Dikaros, I. C.; Sapountzakis, E. J.; Argyridi, A. K.

    2016-05-01

    In this paper a general formulation for the nonuniform warping dynamic analysis of beams of arbitrary simply or multiply connected cross section, under arbitrary external loading and general boundary conditions is presented taking into account the effects of rotary and warping inertia. The nonuniform warping distributions are taken into account by employing four independent warping parameters multiplying a shear warping function in each direction and two torsional warping functions, respectively, which are obtained by solving the corresponding boundary value problems, formulated exploiting the longitudinal local equilibrium equation. A shear stress "correction" is also performed in order to improve the stress field arising from the employed kinematical considerations. Ten initial boundary value problems are formulated with respect to the displacement and rotation components as well as to the independent warping parameters and solved using the Analog Equation Method, a Boundary Element Method based technique in combination with an appropriate time integration scheme. The warping functions and the geometric constants including the additional ones due to warping are evaluated employing a pure BEM approach.

  18. Accurate Cross Sections for Microanalysis

    PubMed Central

    Rez, Peter

    2002-01-01

    To calculate the intensity of x-ray emission in electron beam microanalysis requires a knowledge of the energy distribution of the electrons in the solid, the energy variation of the ionization cross section of the relevant subshell, the fraction of ionizations events producing x rays of interest and the absorption coefficient of the x rays on the path to the detector. The theoretical predictions and experimental data available for ionization cross sections are limited mainly to K shells of a few elements. Results of systematic plane wave Born approximation calculations with exchange for K, L, and M shell ionization cross sections over the range of electron energies used in microanalysis are presented. Comparisons are made with experimental measurement for selected K shells and it is shown that the plane wave theory is not appropriate for overvoltages less than 2.5 V. PMID:27446747

  19. Homogenization of rectangular cross-section fibre-reinforced materials: bending-torsion effects

    NASA Astrophysics Data System (ADS)

    El Jarroudi, Mustapha; Er-Riani, Mustapha

    2016-07-01

    We study the homogenization of an elastic material in contact with periodic parallel elastic rectangular cross-section fibres of higher rigidity. The interactions between the matrix and the fibres are described by a local adhesion contact law with interfacial adhesive stiffness parameter depending on the period. Assuming that the Lamé constants in the fibres and the stiffness parameter have appropriate orders of magnitude, we derive a class of energy functionals involving extension, flexure and torsion terms.

  20. Effect of cross-sectional buckling on the behavior of ACS support columns

    SciTech Connect

    Kennedy, J.M.; Belytschko, T.B.

    1983-01-01

    These analyses of the performance of the support columns for the above-core structures (ACS) have two principal aims: (1) to predict the forces exerted by the column in a hypothetical core-disruptive accident (HCDA) so that the motion of the ACS can be predicted in a coupled fluid-structure analysis, (2) to provide the strains and deformations of the columns so that situations which lead to complete failure of the support system can be identified. In previous studies, the columns were represented by beam elements so changes in the cross section could not be treated. While the columns in many designs are relatively thick-walled, scale-model tests performed at SRI indicate significant changes in the cross section. Therefore, models have been developed in which the portions of the column which undergo significant changes in cross section are modeled by plate elements. For the purpose of comparing the plate-beam models in the context of the loads expected in an HCDA, its predictions were compared to experimental results obtained in the SRI scale model tests. The solutions were obtained by the code SAFE/RAS; a new plate element was added to that program to perform these studies.

  1. Effectiveness Measures for Cross-Sectional Studies: A Comparison of Value-Added Models and Contextualised Attainment Models

    ERIC Educational Resources Information Center

    Lenkeit, Jenny

    2013-01-01

    Educational effectiveness research often appeals to "value-added models (VAM)" to gauge the impact of schooling on student learning net of the effect of student background variables. A huge amount of cross-sectional studies do not, however, meet VAM's requirement for longitudinal data. "Contextualised attainment models (CAM)" measure the influence…

  2. A Cross-Sectional Study of the Cardiovascular Effects of Welding Fumes

    PubMed Central

    Li, Huiqi; Hedmer, Maria; Kåredal, Monica; Björk, Jonas; Stockfelt, Leo; Tinnerberg, Håkan; Albin, Maria; Broberg, Karin

    2015-01-01

    Objectives Occupational exposure to particulate air pollution has been associated with an increased risk of cardiovascular disease. However, the risk to welders working today remains unclear. We aimed to elucidate the cardiovascular effects of exposure to welding fumes. Methods In a cross-sectional study, structured interviews and biological sampling were conducted for 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal breathing zone sampling of respirable dust was performed. Blood pressure (BP) and endothelial function (using peripheral arterial tonometry) were measured. Plasma and serum samples were collected from peripheral blood for measurement of C-reactive protein, low-density lipoprotein, homocysteine, serum amyloid A, and cytokines. Results Welders were exposed to 10-fold higher levels of particles than controls. Welders had significantly higher BP compared to controls, an average of 5 mm Hg higher systolic and diastolic BP (P≤0.001). IL-8 was 3.4 ng/L higher in welders (P=0.010). Years working as a welder were significantly associated with increased BP (β=0.35, 95%CI 0.13 – 0.58, P=0.0024 for systolic BP; β=0.32, 95%CI 0.16 – 0.48, P<0.001 for diastolic BP, adjusted for BMI) but exposure to respirable dust was not associated with BP. No clear associations occurred between welding and endothelial function, or other effect markers. Conclusions A modest increase in BP was found among welders compared to controls suggesting that low-to-moderate exposure to welding fumes remains a risk factor for cardiovascular disease. PMID:26147298

  3. The effect of scaling physiological cross-sectional area on musculoskeletal model predictions.

    PubMed

    Bolsterlee, Bart; Vardy, Alistair N; van der Helm, Frans C T; Veeger, H E J DirkJan

    2015-07-16

    Personalisation of model parameters is likely to improve biomechanical model predictions and could allow models to be used for subject- or patient-specific applications. This study evaluates the effect of personalising physiological cross-sectional areas (PCSA) in a large-scale musculoskeletal model of the upper extremity. Muscle volumes obtained from MRI were used to scale PCSAs of five subjects, for whom the maximum forces they could exert in six different directions on a handle held by the hand were also recorded. The effect of PCSA scaling was evaluated by calculating the lowest maximum muscle stress (σmax, a constant for human skeletal muscle) required by the model to reproduce these forces. When the original cadaver-based PCSA-values were used, strongly different between-subject σmax-values were found (σmax=106.1±39.9 N cm(-2)). A relatively simple, uniform scaling routine reduced this variation substantially (σmax=69.4±9.4 N cm(-2)) and led to similar results to when a more detailed, muscle-specific scaling routine was used (σmax=71.2±10.8 N cm(-2)). Using subject-specific PCSA values to simulate an shoulder abduction task changed muscle force predictions for the subscapularis and the pectoralis major on average by 33% and 21%, respectively, but was <10% for all other muscles. The glenohumeral (GH) joint contact force changed less than 1.5% as a result of scaling. We conclude that individualisation of the model's strength can most easily be done by scaling PCSA with a single factor that can be derived from muscle volume data or, alternatively, from maximum force measurements. However, since PCSA scaling only marginally changed muscle and joint contact force predictions for submaximal tasks, the need for PCSA scaling remains debatable. PMID:26050956

  4. Reaction cross sections of unstable nuclei

    SciTech Connect

    Ozawa, Akira

    2006-11-02

    Experimental studies on reaction cross sections are reviewed. The recent developments of radioactive nuclear beams have enabled us to measure reaction cross-sections for unstable nuclei. Using Glauber-model analysis, effective nuclear matter density distributions of unstable nuclei can be studied. Recent measurements in RIBLL at IMP and RIPS at RIKEN are introduced. The effective matter density distributions for 14-18C are also mentioned.

  5. Neutrino cross-sections: Experiments

    SciTech Connect

    Sánchez, F.

    2015-07-15

    Neutrino-nucleus cross-sections are as of today the main source of systematic errors for oscillation experiments together with neutrino flux uncertainties. Despite recent experimental and theoretical developments, future experiments require even higher precisions in their search of CP violation. We will review the experimental status and explore possible future developments required by next generation of experiments.

  6. Evidence for the healthy immigrant effect in older Chinese immigrants: a cross-sectional study

    PubMed Central

    2014-01-01

    Background Previous work has found that first-generation immigrants to developed nations tend to have better health than individuals born in the host country. We examined the evidence for the healthy immigrant effect and convergence of health status between Chinese immigrants (n = 147) and U.S. born whites (n = 167) participating in the cross-sectional Community Assessment of Freeway Exposure and Health study and residing in the same neighborhoods. Methods We used bivariate and multivariate models to compare disease prevalence and clinical biomarkers. Results Despite an older average age and lower socioeconomic status, Chinese immigrants were less likely to have asthma (OR = 0.20, 95% CI = 0.09–0.48) or cardiovascular disease (OR = 0.44, 95% CI = 0.20–0.94), had lower body mass index (BMI), lower inflammation biomarker levels, lower average sex-adjusted low-density lipoprotein (LDL) cholesterol, and higher average sex-adjusted high-density lipoprotein (HDL) cholesterol. However, there was no significant difference in the prevalence of diabetes or hypertension. Duration of time in the U.S. was related to cardiovascular disease and asthma but was not associated with diabetes, hypertension, BMI, HDL cholesterol, LDL cholesterol, socioeconomic status, or health behaviors. Conclusions The lower CVD and asthma prevalence among the Chinese immigrants may be partially attributed to healthier diets, more physical activity, lower BMI, and less exposure to cigarette smoke. First generation immigrant status may be protective even after about two decades. PMID:24928348

  7. Measuring the acute cardiovascular effects of shisha smoking: a cross-sectional study

    PubMed Central

    Jaffery, Ali; Haq, Adnaan; Bacon, Jenny; Madden, Brendan

    2014-01-01

    Objectives To investigate the acute cardiovascular effects of smoking shisha. Design A cross-sectional study was carried out in six shisha cafes. Participants smoked shisha for a period between 45 min (minimum) and 90 min (maximum). The same brand of tobacco and coal was used. Setting London, UK. Participants Participants were those who had ordered a shisha to smoke and consented to have their blood pressure, heart rate and carbon monoxide levels measured. Excluded subjects were those who had smoked shisha in the previous 24 h, who smoke cigarettes or who suffered from cardiorespiratory problems. Main outcome measures Blood pressure was measured using a sphygmomanometer. Pulse was measured by palpation of the radial artery. Carbon monoxide levels were obtained via a carbon monoxide monitor. These indices were measured before the participants began to smoke shisha and after they finished or when the maximum 90 min time period was reached. Results Mean arterial blood pressure increased from 96 mmHg to 108 mmHg (p < 0.001). Heart rate increased from 77 to 91 bpm (p < 0.001). Carbon monoxide increased from an average of 3 to 35 ppm (p < 0.001). A correlation analysis showed no relationship between carbon monoxide and the other indices measured. Conclusion The acute heart rate, blood pressure and carbon monoxide levels were seen to rise significantly after smoking shisha. The weak correlation between carbon monoxide levels and the other variables suggests that carbon monoxide levels had not contributed to their significant increase. PMID:25057403

  8. Effects of instructional strategies using cross sections on the recognition of anatomical structures in correlated CT and MR images.

    PubMed

    Khalil, Mohammed K; Paas, Fred; Johnson, Tristan E; Su, Yung K; Payer, Andrew F

    2008-01-01

    This research is an effort to best utilize the interactive anatomical images for instructional purposes based on cognitive load theory. Three studies explored the differential effects of three computer-based instructional strategies that use anatomical cross-sections to enhance the interpretation of radiological images. These strategies include: (1) cross-sectional images of the head that can be superimposed on radiological images, (2) transparent highlighting of anatomical structures in radiological images, and (3) cross-sectional images of the head with radiological images presented side-by-side. Data collected included: (1) time spent on instruction and on solving test questions, (2) mental effort during instruction and test, and (3) students' performance to identify anatomical structures in radiological images. Participants were 28 freshmen medical students (15 males and 13 females) and 208 biology students (190 females and 18 males). All studies used posttest-only control group design, and the collected data were analyzed by either t test or ANOVA. In self-directed computer-based environments, the strategies that used cross sections to improve students' ability to recognize anatomic structures in radiological images showed no significant positive effects. However, when increasing the complexity of the instructional materials, cross-sectional images imposed a higher cognitive load, as indicated by higher investment of mental effort. There is not enough evidence to claim that the simultaneous combination of cross sections and radiological images has no effect on the identification of anatomical structures in radiological images for novices. Further research that control for students' learning and cognitive style is needed to reach an informative conclusion. PMID:19177385

  9. Determination of the effective inelastic p anti-p cross-section for the D0 Run II luminosity measurement

    SciTech Connect

    Edwards, T.; Yacoob, S.; Andeen, T.; Begel, M.; Casey, B.C.K.; Partridge, R.; Schellman, H.; Sznajder, A.; /Rio de Janeiro State U.

    2004-11-01

    The authors determine the effective inelastic p{bar p} cross-section into the D0 Luminosity Monitor for all run periods prior to September 2004. This number is used to relate the measured inelastic collision rate to the delivered luminosity. The key ingredients are the inelastic p{bar p} cross-section, the Luminosity Monitor efficiency, and the modeling of kinematic distributions for various inelastic processes used to determine the detector acceptance. The resulting value is {sigma}{sub p{bar p},eff} = 46 {+-} 3 mb.

  10. Effect of the 2 p 2 h cross-section uncertainties on an analysis of neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Ankowski, Artur M.; Benhar, Omar; Mariani, Camillo; Vagnoni, Erica

    2016-06-01

    We report the results of a study aimed at quantifying the impact on the oscillation analysis of the uncertainties associated with the description of the neutrino-nucleus cross section in the two-particle-two-hole sector. The results of our calculations, based on the kinematic method of energy reconstruction and carried out comparing two data-driven approaches, show that the existing discrepancies in the neutrino cross sections have a sizable effect on the extracted oscillation parameters, particularly in the antineutrino channel.

  11. Effects of Instructional Strategies Using Cross Sections on the Recognition of Anatomical Structures in Correlated CT and MR Images

    ERIC Educational Resources Information Center

    Khalil, Mohammed K.; Paas, Fred; Johnson, Tristan E.; Su, Yung K.; Payer, Andrew F.

    2008-01-01

    This research is an effort to best utilize the interactive anatomical images for instructional purposes based on cognitive load theory. Three studies explored the differential effects of three computer-based instructional strategies that use anatomical cross-sections to enhance the interpretation of radiological images. These strategies include:…

  12. Effects of bioaerosol polluted outdoor air on airways of residents: a cross sectional study

    PubMed Central

    Herr, C; zur Nieden, A; Jankofsky, M; Stilianakis, N; Boedeker, R; Eikmann, T

    2003-01-01

    Background: Bioaerosol pollution of workplace and home environments mainly affects airways and mucous membranes. The effect of environmental outdoor residential bioaerosol pollution, for example, livestock holdings, farming, and waste disposal plants, is unclear. Aims: To investigate the perceived health of residents living in areas with measurable outdoor bioaerosol pollution (for example, spores of Aspergillus fumigatus and actinomycetes), and effects of accompanying odours. Methods: In a cross sectional study, double blinded to ongoing microbial measurements, doctors collected 356 questionnaires from residents near a large scale composting site, and from unexposed controls in 1997. Self reported prevalence of health complaints during the past year, doctors' diagnoses, as well as residential odour annoyance were assessed. Microbiological pollution was measured simultaneously in residential outdoor air. Results: Concentrations of >105 colony forming units of thermophilic actinomycetes, moulds, and total bacteria/m3 air were measured 200 m from the site, dropping to near background concentrations within 300 m. Positive adjusted associations were observed for residency within 150–200 m from the site versus unexposed controls for self reported health complaints: "waking up due to coughing", odds ratio (OR) 6.59 (95% confidence interval (CI) 2.57 to 17.73); "coughing on rising or during the day", OR 3.18 (95% CI 1.24 to 8.36); "bronchitis", OR 3.59 (95% CI 1.40 to 9.4); and "excessive tiredness", OR 4.27 (95% CI 1.56 to 12.15). Reports of irritative airway complaints were associated with residency in the highest bioaerosol exposure, 150–200 m (versus residency >400–500 m) from the site, and period of residency more than five years, but not residential odour annoyance. Lifetime prevalence of self reported diseases did not differ with exposure. Conclusions: Bioaerosol pollution of residential outdoor air can occur in concentrations found in occupational

  13. Systematic study of deformation effects on fusion cross-sections using various proximity potentials

    NASA Astrophysics Data System (ADS)

    Rajbongshi, Tapan; Kalita, Kushal

    2014-06-01

    The influence of static quadrupole and hexadecapole (positive & negative) deformation of targets are studied using eleven different versions of nuclear potentials. The height and position of the interaction barrier for the reactions induced by spherical projectile (16O) on the deformed targets such as 166Er, 154Sm and 176Yb have been estimated. It is found that the nucleus-nucleus potential strongly depends on the value of the deformation parameters and orientation of the target. The experimental fusion cross-section of the reactions 16O + 176Yb, 16O +166Er and 16O +154Sm are investigated by applyingWong's formula using various parameterizations of the proximity potential as well as an assessment of the results of a multi-dimensional barrier penetration model (BPM). The fusion cross-sections by Prox 77, Prox 88, Prox 00, Prox 00DP, Denisov DP, Bass 80, CW 76 and AW 95 potentials are found to be better than the rest in comparison to experimental data.

  14. Tunable electromechanical coupling of a carbon nanotube-reinforced variable cross-section nanoswitch with a piezoelectric effect

    NASA Astrophysics Data System (ADS)

    Yang, W. D.; Li, Y. D.; Wang, X.

    2016-08-01

    An analytical method is presented to investigate the pull-in instability of a carbon nanotube (CNT)-reinforced variable cross-section nanoswitch with a piezoelectric effect. Governing equations with variable coefficients are derived based on the nonlocal beam model with geometrical nonlinearity and are solved using the shooting method. All the nonlinear effects of the piezoelectric voltage, van der Waals force, Casimir force, CNT volume fraction, nonlocal parameters and width ratio on the pull-in instability are investigated. The pull-in electrostatic voltage increases with the increment of nonlocal parameters, which exhibits the significant scale-dependent behavior of nanostructures. The results show that the variable cross-section improves the flexural rigidity of the cantilever-type nanoswitch effectively, and that the piezoelectric effect of the piezoelectric layer is utilized to control the electrostatic force induced by the voltage exerted on the elastic layer, owing to piezoelectric materials’ advantages of rapid response, light weight and low energy consumption.

  15. Geometry effects on magnetization dynamics in circular cross-section wires

    SciTech Connect

    Sturma, M.; Toussaint, J.-C. E-mail: daria.gusakova@cea.fr; Gusakova, D. E-mail: daria.gusakova@cea.fr

    2015-06-28

    Three-dimensional magnetic memory design based on circular-cross section nanowires with modulated diameter is the emerging field of spintronics. The consequences of the mutual interaction between electron spins and local magnetic moments in such non-trivial geometries are still open to debate. This paper describes the theoretical study of domain wall dynamics within such wires subjected to spin polarized current. We used our home-made finite element software to characterize the variety of domain wall dynamical regimes observed for different constriction to wire diameter ratios d/D. Also, we studied how sizeable geometry irregularities modify the internal micromagnetic configuration and the electron spin spatial distribution in the system, the geometrical reasons underlying the additional contribution to the system's nonadiabaticity, and the specific domain wall width oscillations inherent to fully three-dimensional systems.

  16. Cross sections for 14-eV e-H{sub 2} resonant collisions: Isotope effect in dissociative electron attachment

    SciTech Connect

    Celiberto, R.; Janev, R. K.; Wadehra, J. M.; Laricchiuta, A.

    2011-07-15

    The process of dissociative attachment of electrons to molecular hydrogen and its isotopes in the energy range at approximately 14 eV is investigated. The dissociative electron attachment cross sections for all six hydrogen isotopes are calculated over an extended range of electron energies using the local complex potential model with the excited Rydberg {sup 2}{Sigma}{sub g}{sup +} electronic state of H{sub 2}{sup -} acting as the intermediate resonant state. A significant isotope effect in theoretical electron attachment cross sections is observed, in agreement with previous predictions and experimental observations. A two-parameter analytic expression for the cross section is derived from the theory that fits accurately the numerically calculated cross sections for all isotopes. Similarly, an analytic mass-scaling relation is derived from the theory that accurately reproduces the numerically calculated rate coefficients for all isotopes in the 0.1-1000 eV temperature range by using the rate coefficient for the H{sub 2} isotope only. The latter is represented by an analytic fit expression with two parameters only.

  17. Recommended Dosimetry Cross Section Compendium.

    Energy Science and Technology Software Center (ESTSC)

    1994-07-11

    Version 00 The data is recommended for spectrum determination applications and for the prediction of neutron activation of typical radiation sensor materials. The library has been tested for consistency of the cross sections in a wide variety of neutron environments. The results and cautions from this testing have been documented. The data has been interfaced with radiation transport codes, such as TWODANT-SYS (CCC-547) and MCNP (CCC-200), in order to compare calculated and measured activities formore » benchmark reactor experiments.« less

  18. Effect of diameter of nanoparticles and capture cross-section library on macroscopic dose enhancement in boron neutron capture therapy

    PubMed Central

    Farhood, Bagher

    2014-01-01

    Purpose The aim of this study is evaluation of the effect of diameter of 10B nanoparticles and various neutron capture cross-section libraries on macroscopic dose enhancement in boron neutron capture therapy (BNCT). Material and methods MCNPX Monte Carlo code was used for simulation of a 252Cf source, a soft tissue phantom and a tumor containing 10B nanoparticles. Using 252Cf as a neutron source, macroscopic dose enhancement factor (MDEF) and total dose rate in tumor in the presence of 100, 200, and 500 ppm of 10B nanoparticles with 25 nm, 50 nm, and 100 nm diameters were calculated. Additionally, the effect of ENDF, JEFF, JENDL, and CENDL neutron capture cross-section libraries on MDEF was evaluated. Results There is not a linear relationship between the average MDEF value and nanoparticles’ diameter but the average MDEF grows with increased concentration of 10B nanoparticles. There is an increasing trend for average MDEF with the tumor distance. The average MDEF values were obtained the same for various neutron capture cross-section libraries. The maximum and minimum doses that effect on the total dose in tumor were neutron and secondary photon doses, respectively. Furthermore, the boron capture related dose component reduced in some extent with increase of diameter of 10B nanoparticles. Conclusions Based on the results of this study, it can be concluded that from physical point of view, various nanoparticle diameters have no dominant effect on average MDEF value in tumor. Furthermore, it is concluded that various neutron capture cross-section libraries are resulted to the same macroscopic dose enhancements. However, it is predicted that taking into account the biological effects for various nanoparticle diameters will result in different dose enhancements. PMID:25834582

  19. Effect of the Mott cross section on the determination of the charge of ultraheavy cosmic rays from emulsion tracks

    NASA Technical Reports Server (NTRS)

    Eby, P. B.; Morgan, S. H.; Parnell, T. A.

    1978-01-01

    Energy deposition due to secondary electrons is calculated as a function of distance from the axis of the track of a heavy ion. The calculation incorporates the empirical formulas of Kobetich and Katz (1968) for delta-ray energy dissipation. Both the Mott and Born-approximation expressions for the delta-ray energy distributions are used, and the results are compared. The energy deposition projected along a line perpendicular to the track is also calculated. These results are used to estimate the effect that the use of the Mott cross section would have in the interpretation of photometric measurements on emulsion tracks of trans-iron cosmic-ray particles. It is shown that the use of 50 keV as a characteristic track-formation electron energy to estimate the effect of the Mott cross section systematically overestimates charge as derived from emulsions for Z greater than 20.

  20. The Effect of the Residual Ion Potential on the Fully Differential Cross Section of Helium for Ionization by Electron Impact

    SciTech Connect

    Toth, A.; Nagy, L.

    2011-10-03

    We have carried out calculations for the fully differential cross section of the ionization of helium by electron projectiles. In order to study the effect of the residual ion potential, we employed three models, and tested them for the coplanar and perpendicular plane geometry. In spite of the simplicity of our models, the results for the coplanar case are in fair agreement with the available experimental data. The results for the perpendicular geometry need more improvement.

  1. Effect of Infertility on the Quality of Life, A Cross- Sectional Study

    PubMed Central

    Direkvand-Moghadam, Ashraf; Direkvand-Moghadam, Azadeh

    2014-01-01

    Introduction: Infertility is a major life crisis which causes serious mental problems and stressful experience of infertile couples. Therefore, the aim of the present study was to compare the quality of life in fertile and infertile women. Materials and Methods: In a cross - sectional study compared the quality of life in 450 women attending both public and private health centers in Ilam, western of Iran, in 2013. Participants were divided in two groups’ fertilities and infertilities women. Data was collected by trained research midwives using demographic and SF-36 questionnaires. SPSS software Package 16 was used to analyze the data of this project. Differences were regarded statistically significant with an alpha error of 0.05. Results: Significant difference was reported in mean age between fertile and infertile women (p=0.003). Mean scores of all Mental dimensions of quality of life were higher in fertile women in comparison with infertile women. This difference was statistically significant (58.35±19.43 vs 56.56±13.18 respectively) (p= 0.000).The mean score of all physical dimensions have not statistically significant difference in fertile and infertile women (79.77± 23.19 vs 74.96±23.45 respectively) (p= 0.441). Conclusion: In most infertile women, the mean score of Mental dimensions of quality of life is lower in comparison with fertile women, therefore, it is necessary the used of counseling and treatment programs in infertile women. PMID:25478412

  2. Quantum interference effects in Bi2Se3 topological insulator nanowires with variable cross-section lengths

    NASA Astrophysics Data System (ADS)

    Iorio, Paolino; Perroni, Carmine Antonio; Cataudella, Vittorio

    2016-04-01

    Stimulated by the recent realization of three dimensional topological insulator nanowire interferometers, a theoretical analysis of quantum interference effects on the low energy spectrum of Bi2Se3 nanowires is presented. The electronic properties are analyzed in nanowires with circular, square and rectangular cross-sections starting from a continuum three dimensional model with particular emphasis on magnetic and geometrical effects. The theoretical study is based on numerically exact diagonalizations of the discretized model for all the geometries. In the case of the cylindrical wire, an approximate analytical solution of the continuum model is also discussed. Although a magnetic field corresponding to half quantum flux is expected to close the band gap induced by Berry phase, in all the studied geometries with finite area cross-sections, the gap closes for magnetic fields typically larger than those expected. Furthermore, unexpectedly, due to geometrical quantum interference effects, for a rectangular wire with a sufficiently large aspect ratio and smaller side ranging from 50 Å and 100 Å, the gap closes for a specific finite area cross-section without the application of a magnetic field.

  3. (Fast neutron cross section measurements)

    SciTech Connect

    Not Available

    1991-01-01

    In the 14 MeV Neutron Laboratory, we have continued the development of a facility that is now the only one of its kind in operation in the United States. We have refined the klystron bunching system described in last year's report to the point that 1.2 nanosecond pulses have been directly measured. We have tested the pulse shape discrimination capability of our primary NE 213 neutron detector. We have converted the RF sweeper section of the beamline to a frequency of 1 MHz to replace the function of the high voltage pulser described in last year's report which proved to be difficult to maintain and unreliable in its operation. We have also overcome several other significant experimental difficulties, including a major problem with a vacuum leak in the main accelerator column. We have completed additional testing to prove the remainder of the generation and measurement systems, but overcoming some of these experimental difficulties has delayed the start of actual data taking. We are now in a position to begin our first series of ring geometry elastic scattering measurements, and these will be underway before the end of the current contract year. As part of our longer term planning, we are continuing the conceptual analysis of several schemes to improve the intensity of our current pulsed beam. These include the provision of a duoplasmatron ion source and/or the provision of preacceleration bunching. Additional details are given later in this report. A series of measurements were carried out at the Tandem Dynamatron Facility involving the irradiation of a series of yttrium foils and the determination of activation cross sections using absolute counting techniques. The experimental work has been completed, and final analysis of the cross section data will be completed within several months.

  4. Electron-Impact Ionization Cross Section Database

    National Institute of Standards and Technology Data Gateway

    SRD 107 Electron-Impact Ionization Cross Section Database (Web, free access)   This is a database primarily of total ionization cross sections of molecules by electron impact. The database also includes cross sections for a small number of atoms and energy distributions of ejected electrons for H, He, and H2. The cross sections were calculated using the Binary-Encounter-Bethe (BEB) model, which combines the Mott cross section with the high-incident energy behavior of the Bethe cross section. Selected experimental data are included.

  5. Effect of momentum dependent interactions and nucleonic cross-section on directed flow (v{sub 1})

    SciTech Connect

    Jain, Anupriya; Vinayak, Karan Singh; Kumar, Suneel

    2013-07-15

    The descriptive analysis for the effect of momentum dependent interactions and nucleonic cross-section (isospin dependent and isospin-independent) on the neutron–proton directed flow (v{sub 1}), within the framework of the isospin dependent quantum molecular dynamics model is presented. Our study shows that, the directed flow of both neutrons and protons is affected by the momentum dependence of nuclear equation of state and the isospin dependence of nucleon–nucleon cross-section. A soft momentum dependent (SM) equation of state is found to be more compatible with the experimental data. -- Highlights: •Role of rapidity cut on transverse flow has been explored. •p{sub t} differential flow for protons and neutrons has been studied. •Role of MDI on directed flow has been studied.

  6. Modeling the heavy ion upset cross section

    NASA Astrophysics Data System (ADS)

    Connell, L. W.; McDaniel, P. J.; Prinja, A. K.; Sexton, F. W.

    1995-04-01

    The standard Rectangular Parallelepiped (RPP) construct is used to derive a closed form expression for, sigma-bar (theta, phi, L) the directional-spectral heavy ion upset cross section. This is an expected value model obtained by integrating the point-value cross section model, sigma (theta, phi, L, E), also developed here, with the Weibull density function, f(E), assumed to govern the stochastic behavior of the upset threshold energy, E. A comparison of sigma-bar (theta, phi, L) with experimental data show good agreement, lending strong credibility to the hypothesis that E-randomness is responsible for the shape of the upset cross section curve. The expected value model is used as the basis for a new, rigorous mathematical formulation of the effective cross section concept. The generalized formulation unifies previous corrections to the inverse cosine scaling, collapsing to Petersen's correction, (cos theta - (h/l) sin theta)(sup -1), near threshold and Sexton's, (cos theta + (h/l) sin theta)(sup -1), near saturation. The expected value cross section model therefore has useful applications in both upset rate prediction and test data analysis.

  7. Improved cross section calculations for astrophysical applications

    NASA Technical Reports Server (NTRS)

    Silberberg, R.; Tsao, C. H.; Letaw, J. R.

    1985-01-01

    Modifications are proposed for the semiempirical equations and parameters of Silberberg and Tsao (1973) for partial cross section calculations of proton-nucleus reactions in cosmic rays. These modifications include: adjustment of general parameters; modification of energy dependence; effects of nuclear alpha-particle structure, deuteron emission, and even-charged products; peripheral reactions; fission reactions; averaging cross sections near boundaries of different parameters; elimination of certain special cases; and treatment of the Pt to Pb group that cannot yet be generalized to Z(t) less than 76.

  8. Cross Sections From Scalar Field Theory

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Dick, Frank; Norman, Ryan B.; Nasto, Rachel

    2008-01-01

    A one pion exchange scalar model is used to calculate differential and total cross sections for pion production through nucleon- nucleon collisions. The collisions involve intermediate delta particle production and decay to nucleons and a pion. The model provides the basic theoretical framework for scalar field theory and can be applied to particle production processes where the effects of spin can be neglected.

  9. Effect of shell drilling stiffness on response calculations of rectangular plates and tubes of rectangular cross-section under compression.

    SciTech Connect

    Gorman, Jhana; Hales, Jason Dean; Corona, Edmundo

    2010-05-01

    This report considers the calculation of the quasi-static nonlinear response of rectangular flat plates and tubes of rectangular cross-section subjected to compressive loads using quadrilateralshell finite element models. The principal objective is to assess the effect that the shell drilling stiffness parameter has on the calculated results. The calculated collapse load of elastic-plastic tubes of rectangular cross-section is of particular interest here. The drilling stiffness factor specifies the amount of artificial stiffness that is given to the shell element drilling Degree of freedom (rotation normal to the plane of the element). The element formulation has no stiffness for this degree of freedom, and this can lead to numerical difficulties. The results indicate that in the problems considered it is necessary to add a small amount of drilling tiffness to obtain converged results when using both implicit quasi-statics or explicit dynamics methods. The report concludes with a parametric study of the imperfection sensitivity of the calculated responses of the elastic-plastic tubes with rectangular cross-section.

  10. Effect of obesity and low back pain on spinal mobility: a cross sectional study in women

    PubMed Central

    2010-01-01

    Background obesity is nowadays a pandemic condition. Obese subjects are commonly characterized by musculoskeletal disorders and particularly by non-specific chronic low back pain (cLBP). However, the relationship between obesity and cLBP remains to date unsupported by an objective measurement of the mechanical behaviour of the spine and its morphology in obese subjects. Such analysis may provide a deeper understanding of the relationships between function and the onset of clinical symptoms. Purpose to objectively assess the posture and function of the spine during standing, flexion and lateral bending in obese subjects with and without cLBP and to investigate the role of obesity in cLBP. Study design Cross-sectional study Patient sample thirteen obese subjects, thirteen obese subjects with cLBP, and eleven healthy subjects were enrolled in this study. Outcome measures we evaluated the outcome in terms of angles at the initial standing position (START) and at maximum forward flexion (MAX). The range of motion (ROM) between START and MAX was also computed. Methods we studied forward flexion and lateral bending of the spine using an optoelectronic system and passive retroreflective markers applied on the trunk. A biomechanical model was developed in order to analyse kinematics and define angles of clinical interest. Results obesity was characterized by a generally reduced ROM of the spine, due to a reduced mobility at both pelvic and thoracic level; a static postural adaptation with an increased anterior pelvic tilt. Obesity with cLBP is associated with an increased lumbar lordosis. In lateral bending, obesity with cLBP is associated with a reduced ROM of the lumbar and thoracic spine, whereas obesity on its own appears to affect only the thoracic curve. Conclusions obese individuals with cLBP showed higher degree of spinal impairment when compared to those without cLBP. The observed obesity-related thoracic stiffness may characterize this sub-group of patients, even

  11. Photoproduction total cross section and shower development

    NASA Astrophysics Data System (ADS)

    Cornet, F.; García Canal, C. A.; Grau, A.; Pancheri, G.; Sciutto, S. J.

    2015-12-01

    The total photoproduction cross section at ultrahigh energies is obtained using a model based on QCD minijets and soft-gluon resummation and the ansatz that infrared gluons limit the rise of total cross sections. This cross section is introduced into the Monte Carlo system AIRES to simulate extended air showers initiated by cosmic ray photons. The impact of the new photoproduction cross section on common shower observables, especially those related to muon production, is compared with previous results.

  12. Molecular Structures and Ion Mobility Cross Sections: Analysis of the Effects of He and N2 Buffer Gas.

    PubMed

    Bleiholder, Christian; Johnson, Nicholas R; Contreras, Stephanie; Wyttenbach, Thomas; Bowers, Michael T

    2015-07-21

    An empirically observed correlation between ion mobility cross sections in helium and nitrogen buffer gases was examined as a function of temperature, molecular size, and shape. Experimental cross sections were determined for tetraglycine, bradykinin, angiotensin 2, melittin, and ubiquitin at 300 K and in the range from 80 to 550 K on home-built instruments and calculated by the projection superposition approximation (PSA) method. The PSA was also used to predict cross sections for larger systems such as human pancreatic alpha-amylase, concanavalin, Pichia pastoris lysyl oxidase, and Klebsiella pneumoniae acetolactate synthase. The data show that the ratio of cross sections in helium and nitrogen depends significantly on the temperature of the buffer gas as well as the size and shape of the analyte ion. Therefore, the analysis of the data indicates that a simple formula that seeks to quantitatively relate the momentum transfer cross sections observed in two distinct buffer gases lacks a sound physical basis. PMID:26076363

  13. Effect of wave function on the proton induced L XRP cross sections for {sub 62}Sm and {sub 74}W

    SciTech Connect

    Shehla,; Kaur, Rajnish; Kumar, Anil; Puri, Sanjiv

    2015-08-28

    The L{sub k}(k= 1, α, β, γ) X-ray production cross sections have been calculated for {sub 74}W and {sub 62}Sm at different incident proton energies ranging 1-5 MeV using theoretical data sets of different physical parameters, namely, the Li(i=1-3) sub-shell X-ray emission rates based on the Dirac-Fork (DF) model, the fluorescence and Coster Kronig yields based on the Dirac- Hartree-Slater (DHS) model and two sets the proton ionization cross sections based on the DHS model and the ECPSSR in order to assess the influence of the wave function on the XRP cross sections. The calculated cross sections have been compared with the measured cross sections reported in the recent compilation to check the reliability of the calculated values.

  14. Cross Sections: No. 1 Hold section at Fr 24 Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cross Sections: No. 1 Hold section at Fr 24 Looking Fwd, No 1 Hold Section at Fr 28 Looking Aft, No 2 Hold Section at Fr 48 Looking Aft, No 3 Hold Section at Fr 70 Looking Aft, No 4 Hold Section at Fr 90 Looking Aft - General John Pope, Suisun Bay Reserve Fleet, Benicia, Solano County, CA

  15. Electron Photon Interaction Cross Sections

    SciTech Connect

    Cullen, D. E.

    2014-11-01

    Version 00 The Electron Photon Interaction Cross Sections, EPICS, provides the atomic data needed to perform coupled Electron-Photon transport calculations, to produce accurate macroscopic results, such as energy deposit and dose. Atomic data is provided for elements, Z = 1 to 100, over the energy range 10 eV to 100 GeV; note that nuclear data, such as photo-nuclear, and data for compounds, are not included. All data is in a simple computer independent text format that is standard and presented to a high precision that can be easily read by computer codes written in any computer language, e.g., C, C++, and FORTRAN. EPICS includes four separate data bases that are designed to be used in combination, these include, • The Evaluated Electron Data Library (EEDL), to describe the interaction of electrons with matter. • The Evaluated Photon Data Library (EPDL), to describe the interaction of photons with matter. • The Evaluated Atomic Data Library (EADL), to describe the emission of electrons and photons back to neutrality following an ionizing event, caused by either electron or photon interactions. • The Evaluated Excitation Data Library (EXDL), to describe the excitation of atoms due to photon interaction. All of these are available in the Extended ENDL format (ENDLX) in which the evaluations were originally performed. The first three are also available in the ENDF format; as yet ENDF does not include formats to handle excitation data (EXDL).

  16. Electron Photon Interaction Cross Sections

    Energy Science and Technology Software Center (ESTSC)

    2014-11-01

    Version 00 The Electron Photon Interaction Cross Sections, EPICS, provides the atomic data needed to perform coupled Electron-Photon transport calculations, to produce accurate macroscopic results, such as energy deposit and dose. Atomic data is provided for elements, Z = 1 to 100, over the energy range 10 eV to 100 GeV; note that nuclear data, such as photo-nuclear, and data for compounds, are not included. All data is in a simple computer independent text formatmore » that is standard and presented to a high precision that can be easily read by computer codes written in any computer language, e.g., C, C++, and FORTRAN. EPICS includes four separate data bases that are designed to be used in combination, these include, • The Evaluated Electron Data Library (EEDL), to describe the interaction of electrons with matter. • The Evaluated Photon Data Library (EPDL), to describe the interaction of photons with matter. • The Evaluated Atomic Data Library (EADL), to describe the emission of electrons and photons back to neutrality following an ionizing event, caused by either electron or photon interactions. • The Evaluated Excitation Data Library (EXDL), to describe the excitation of atoms due to photon interaction. All of these are available in the Extended ENDL format (ENDLX) in which the evaluations were originally performed. The first three are also available in the ENDF format; as yet ENDF does not include formats to handle excitation data (EXDL).« less

  17. [Fast neutron cross section measurements

    SciTech Connect

    Knoll, G.F.

    1992-10-26

    From its inception, the Nuclear Data Project at the University of Michigan has concentrated on two major objectives: (1) to carry out carefully controlled nuclear measurements of the highest possible reliability in support of the national nuclear data program, and (2) to provide an educational opportunity for students with interests in experimental nuclear science. The project has undergone a successful transition from a primary dependence on our photoneutron laboratory to one in which our current research is entirely based on a unique pulsed 14 MeV fast neutron facility. The new experimental facility is unique in its ability to provide nanosecond bursts of 14 MeV neutrons under conditions that are clean'' and as scatter-free as possible, and is the only one of its type currently in operation in the United States. It has been designed and put into operation primarily by graduate students, and has met or exceeded all of its important initial performance goals. We have reached the point of its routine operation, and most of the data are now in hand that will serve as the basis for the first two doctoral dissertations to be written by participating graduate students. Our initial results on double differential neutron cross sections will be presented at the May 1993 Fusion Reactor Technology Workshop. We are pleased to report that, after investing several years in equipment assembly and optimization, the project has now entered its data production'' phase.

  18. Effective Fluorescence Lifetime and Stimulated Emission Cross-Section of Nd/Cr:YAG Ceramics under CW Lamplight Pumping

    NASA Astrophysics Data System (ADS)

    Saiki, Taku; Motokoshi, Shinji; Imasaki, Kazuo; Fujioka, Kana; Fujita, Hisanori; Nakatsuka, Masahiro; Izawa, Yasukazu; Yamanaka, Chiyoe

    2008-10-01

    Remarkable improvements in the lifetime of the Nd upper level and in the effective stimulated emission cross-section of Nd/Cr:YAG ceramics have been theoretically and experimentally studied. Until recently, it had been thought that the long energy transition time from Cr ions to Nd ions of Nd/Cr:YAG adversely affects laser action, degrading optical-optical conversion efficiency under CW and flash lamp pumping. However, current research showed that high-efficiency energy transition has a positive effect on laser action. The effective lifetime is increased from 0.23 to 1.1 ms and the emission cross-section is effectively increased to three times for that of the conventional Nd:YAG. A small signal gain is significantly improved, and the saturation power density is reduced to 1/10 that of the Nd:YAG for the same pumping power density. A CW laser light generated in a laser diode (LD)-pumped 1064 nm Nd:YAG laser oscillator was amplified, and the measured output power was saturated. The output laser power calculated using theoretical saturation power density was consistent with the experimental results.

  19. Well-Being and Institutional Care in Older Adults: Cross-Sectional and Time Effects of Provided and Received Support

    PubMed Central

    Kroemeke, Aleksandra; Gruszczynska, Ewa

    2016-01-01

    Background The aim of the study was to examine the cross-sectional and longitudinal effects of provided and received support on older adults’ subjective well-being (positive affect and depression) and to examine whether being a recipient of institutional care moderates these effects. Methods Social support (provided and received), positive affect, and depressive symptoms were assessed twice (at baseline and 1 month later) for 277 older adults (age 77.39 ± 9.20 years, 67.50% women, 65% residents of an institutional care facility). Findings Two structural equation models were analyzed: cross-sectional (at baseline) and longitudinal (after 1 month). The first model revealed a significant positive relationship between providing and receiving support and positive affect, and a negative relationship between receiving support and depression. However, being a recipient of institutional care appeared to be a significant moderator in the longitudinal model. Specifically, the findings indicated effects of both providing and receiving support on positive affect but only for noninstitutionalized older adults. Discussion Although both types of support may be beneficial for older adults, their effects depend on the nature of social exchange and the dimensions of well-being. This suggests that such factors should be systematically investigated in future research. PMID:27548721

  20. Recent fission cross section standards measurements

    SciTech Connect

    Wasson, O.A.

    1985-01-01

    The /sup 235/U(n,f) reaction is the standard by which most neutron induced fission cross sections are determined. Most of these cross sections are derived from relatively easy ratio measurements to /sup 235/U. However, the more difficult /sup 235/U(n,f) cross section measurements require the use of advanced neutron detectors for the determination of the incident neutron fluence. Examples of recent standard cross section measurements are discussed, various neutron detectors are described, and the status of the /sup 235/U(n,f) cross section standard is assessed. 23 refs., 8 figs., 4 tabs.

  1. SNL RML recommended dosimetry cross section compendium

    SciTech Connect

    Griffin, P.J.; Kelly, J.G.; Luera, T.F.; VanDenburg, J.

    1993-11-01

    A compendium of dosimetry cross sections is presented for use in the characterization of fission reactor spectrum and fluence. The contents of this cross section library are based upon the ENDF/B-VI and IRDF-90 cross section libraries and are recommended as a replacement for the DOSCROS84 multigroup library that is widely used by the dosimetry community. Documentation is provided on the rationale for the choice of the cross sections selected for inclusion in this library and on the uncertainty and variation in cross sections presented by state-of-the-art evaluations.

  2. Formulation and solution of the delayed gamma dose rate problem using the concept of effective delayed gamma production cross section

    SciTech Connect

    Liew, S.L.; Ku, L.P.

    1989-06-01

    With appropriate approximations, the delayed gamma dose rate problem can be formulated in terms of the effective delayed gamma production cross section. The coupled neutron-delayed-gamma transport equations then take the same form as the coupled neutron-prompt-gamma transport equations and they can, therefore, be solved directly in the same manner. This eliminates the need for the tedious and error prone flux coupling step in conventional calculations. Mathematical formulation and solution algorithms are derived. The advantages of this method are illustrated by an example of its application in the solution of a practical design problem. 62 refs., 10 figs., 1 tab.

  3. Effects of the Communities That Care System on Cross-Sectional Profiles of Adolescent Substance Use and Delinquency

    PubMed Central

    Van Horn, M. Lee; Fagan, Abigail A.; Hawkins, J. David; Oesterle, Sabrina

    2014-01-01

    Introduction Adolescent substance use and delinquency are major public health problems. Although community–based prevention strategies have been recommended to produce population-level reductions in rates of substance use and delinquency, few models show evidence of effectiveness. Purpose To test the efficacy of a community–based prevention system, Communities That Care (CTC), in reducing community rates of problem behaviors, particularly effects on specific profiles of adolescent substance use and delinquency in eighth and tenth graders. Methods Twenty-four communities were randomized to CTC intervention or control groups. Data were collected from 14,099 eighth and tenth grade students in these communities using anonymous cross-sectional surveys in 2004 and 2010 and analyzed in 2012. Outcomes were four different profiles of self–reported substance use and delinquency in eighth grade and five profiles in tenth grade. Results In the cross-sectional 2010 data, there was no intervention effect on the probability of experimenting with substances or of substance use coupled with delinquent activities for either grade. However, tenth graders in intervention communities were significantly less likely to be alcohol users than those in control communities (OR=0.69, CI=0.48, 1.00). Conclusions Cross–sectional population surveys showed evidence of CTC effects in reducing tenth grade alcohol users but not experimenters. A community-wide reduction in adolescent alcohol use is important because alcohol is the most commonly used illicit substance during adolescence, and early initiation of alcohol use has been associated with alcohol-related disorders in adulthood. Failure to find hypothesized effects on experimenters qualifies these results. PMID:24986217

  4. Cross Sections: No 6 Hold Section at Fr 178 Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Cross Sections: No 6 Hold Section at Fr 178 Looking Fwd, No 7 Hold Section at No 154 Looking Fwd, No 7 Hold Section at Fr 195 Looking Fwd Showing Trans 194, No 7 Hold Section at Fr 198 Looking Fwd - General John Pope, Suisun Bay Reserve Fleet, Benicia, Solano County, CA

  5. Pulse duration effects on laser-assisted electron transfer cross section for He2+ ions colliding with atomic hydrogen

    NASA Astrophysics Data System (ADS)

    Domínguez-Gutiérrez, Francisco Javier; Cabrera-Trujillo, Remigio

    2014-08-01

    We study the effect of the pulse duration for an ultra-fast and intense laser on the fundamental process of electron capture by analyzing the excitation probability into the n = 2 and n = 3 states when He2+ collides with atomic hydrogen in the 0.05-10 keV/amu energy range, a region of interest for diagnostic processes on plasma and fusion power reactors. We solve the time-dependent Schrödinger equation to calculate the electron capture probability by means of a finite-differences, as well as by an electron-nuclear dynamics approach. In particular, we study the effects of 1, 3, 6, and 10 fs laser pulses at FWHM, wavelength of 780 nm and intensity of 3.5 × 1012 W/cm2. We report good agreement for the laser-free state and total electron transfer cross-sections when compared to available theoretical and experimental data. The effect of the laser pulse on the electron capture probability as a function of the impact parameter is such that the charge exchange probability increases considerably in the impact parameter radial region with an increase in the amplitude oscillations and a phase shift on the Stückelberg oscillations. We find an increase on the total electron exchange cross-section for low projectile collision energy when compared to the laser-free case with a minimal effect at high collision energies. We find that the 1 fs laser pulse has a minimal effect, except for very low collision energies. Although in general, the longer the laser pulse, the larger the electron capture probability, at very low collision energies all pulse widths have an effect. For processes in the atto-second region, our findings suggest that to enhance the laser-assisted charge exchange, the best region for short pulses is at very low collision energies. We also find that the s and p state charge exchange cross section are equally affected. We provide a qualitative discussion of these findings.

  6. Studies on mass energy-absorption coefficients and effective atomic energy-absorption cross sections for carbohydrates

    NASA Astrophysics Data System (ADS)

    Ladhaf, Bibifatima M.; Pawar, Pravina P.

    2015-04-01

    We measured here the mass attenuation coefficients (μ/ρ) of carbohydrates, Esculine (C15H16O9), Sucrose (C12H22O11), Sorbitol (C6H14O6), D-Galactose (C6H12O6), Inositol (C6H12O6), D-Xylose (C5H10O5) covering the energy range from 122 keV up to 1330 keV photon energies by using gamma ray transmission method in a narrow beam good geometry set-up. The gamma-rays were detected using NaI(Tl) scintillation detection system with a resolution of 8.2% at 662 keV. The attenuation coefficient data were then used to obtain the total attenuation cross-section (σtot), molar extinction coefficients (ε), mass-energy absorption coefficients (μen/ρ) and effective (average) atomic energy-absorption cross section (σa,en) of the compounds. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

  7. Cross-Sectional and Longitudinal Effects of Racism on Mental Health Among Residents of Black Neighborhoods in New York City

    PubMed Central

    Goodman, Melody S.

    2015-01-01

    Objectives. We investigated the impact of reported racism on the mental health of African Americans at cross-sectional time points and longitudinally, over the course of 1 year. Methods. The Black Linking Inequality, Feelings, and the Environment (LIFE) Study recruited Black residents (n = 144) from a probability sample of 2 predominantly Black New York City neighborhoods during December 2011 to June 2013. Respondents completed self-report surveys, including multiple measures of racism. We conducted assessments at baseline, 2-month follow-up, and 1-year follow-up. Weighted multivariate linear regression models assessed changes in racism and health over time. Results. Cross-sectional results varied by time point and by outcome, with only some measures associated with distress, and effects were stronger for poor mental health days than for depression. Individuals who denied thinking about their race fared worst. Longitudinally, increasing frequencies of racism predicted worse mental health across all 3 outcomes. Conclusions. These results support theories of racism as a health-defeating stressor and are among the few that show temporal associations with health. PMID:25521873

  8. Towards the understanding of jet shapes and cross sections in heavy ion collisions using soft-collinear effective theory

    NASA Astrophysics Data System (ADS)

    Chien, Yang-Ting; Vitev, Ivan

    2016-05-01

    We calculate the jet shape and the jet cross section in heavy ion collisions using soft-collinear effective theory (SCET) and its extension with Glauber gluon interactions in the medium (SCETG). We use the previously developed framework to systematically resum the jet shape at next-to-leading logarithmic accuracy, and we consistently include the medium modification by incorporating the leading order medium-induced splitting functions. The calculation provides, for the first time, a quantitative understanding of the jet shape modification measurement in lead-lead collisions at √{s_{NN}} = 2.76 TeV at the LHC. The inclusive jet suppression is also calculated within the same framework beyond the traditional concept of parton energy loss, and the dependence on the centrality, the jet radius and the jet kinematics is examined. In the end we present predictions for the anticipated jet shape and cross section measurements in lead-lead collisions at √{s_{NN}} ≈ 5.1 TeV at the LHC.

  9. Vertically stabilized elongated cross-section tokamak

    DOEpatents

    Sheffield, George V.

    1977-01-01

    This invention provides a vertically stabilized, non-circular (minor) cross-section, toroidal plasma column characterized by an external separatrix. To this end, a specific poloidal coil means is added outside a toroidal plasma column containing an endless plasma current in a tokamak to produce a rectangular cross-section plasma column along the equilibrium axis of the plasma column. By elongating the spacing between the poloidal coil means the plasma cross-section is vertically elongated, while maintaining vertical stability, efficiently to increase the poloidal flux in linear proportion to the plasma cross-section height to achieve a much greater plasma volume than could be achieved with the heretofore known round cross-section plasma columns. Also, vertical stability is enhanced over an elliptical cross-section plasma column, and poloidal magnetic divertors are achieved.

  10. Cross Sections for Electron Collisions with Methane

    SciTech Connect

    Song, Mi-Young Yoon, Jung-Sik; Cho, Hyuck; Itikawa, Yukikazu; Karwasz, Grzegorz P.; Kokoouline, Viatcheslav; Nakamura, Yoshiharu; Tennyson, Jonathan

    2015-06-15

    Cross section data are compiled from the literature for electron collisions with methane (CH{sub 4}) molecules. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, dissociation, ionization, and dissociative attachment. The data derived from swarm experiments are also considered. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed through early 2014.

  11. Theoretical antideuteron-nucleus absorptive cross sections

    NASA Technical Reports Server (NTRS)

    Buck, W. W.; Norbury, J. W.; Townsend, L. W.; Wilson, J. W.

    1993-01-01

    Antideuteron-nucleus absorptive cross sections for intermediate to high energies are calculated using an ion-ion optical model. Good agreement with experiment (within 15 percent) is obtained in this same model for (bar p)-nucleus cross sections at laboratory energies up to 15 GeV. We describe a technique for estimating antinucleus-nucleus cross sections from NN data and suggest that further cosmic ray studies to search for antideuterons and other antinuclei be undertaken.

  12. Universal Parameterization of Absorption Cross Sections

    NASA Technical Reports Server (NTRS)

    Tripathi, R. K.; Cucinotta, Francis A.; Wilson, John W.

    1997-01-01

    This paper presents a simple universal parameterization of total reaction cross sections for any system of colliding nuclei that is valid for the entire energy range from a few AMeV to a few AGeV. The universal picture presented here treats proton-nucleus collision as a special case of nucleus-nucleus collision, where the projectile has charge and mass number of one. The parameters are associated with the physics of the collision system. In general terms, Coulomb interaction modifies cross sections at lower energies, and the effects of Pauli blocking are important at higher energies. The agreement between the calculated and experimental data is better than all earlier published results.

  13. Cross sections required for FMIT dosimetry

    SciTech Connect

    Gold, R.; McElroy, W.N.; Lippincott, E.P.; Mann, F.M.; Oberg, D.L.; Roberts, J.H.; Ruddy, F.H.

    1980-05-02

    The Fusion Materials Irradiation Test (FMIT) facility, currently under construction, is designed to produce a high flux of high energy neutrons for irradiation effects experiments on fusion reactor materials. Characterization of the flux-fluence-spectrum in this rapidly varying neutron field requires adaptation and extension of currently available dosimetry techniques. This characterization will be carried out by a combination of active, passive, and calculational dosimetry. The goal is to provide the experimenter with accurate neutron flux-fluence-spectra at all positions in the test cell. Plans have been completed for a number of experimental dosimetry stations and provision for these facilities has been incorporated into the FMIT design. Overall needs of the FMIT irradiation damage program delineate goal accuracies for dosimetry that, in turn, create new requirements for high energy neutron cross section data. Recommendations based on these needs have been derived for required cross section data and accuracies.

  14. Effective Potential Energies and Transport Cross Sections for Atom-Molecule Interactions of Nitrogen and Nitrogen

    NASA Technical Reports Server (NTRS)

    Stallcop, James R.; Partridge, Harry; Levin, Eugene; Arnold, Jim (Technical Monitor)

    2001-01-01

    The potential energy surfaces for H2-N and N2-N interactions are calculated by accurate ab initio methods and applied to determine transport data. The results confirm that an effective potential energy for accurately determining transport properties can be calculated using a single orientation. A simple method is developed to determine the dispersion coefficients of effective potential energies Effective potential energies required for O2-O collisions are determ=ined. The H2-N, N2-N, O2-H, and O2-O collision integrals are calculated and tabulated for a large range of temperatures. The theoretical values of the N2-N and O2-O diffusion coefficients compare well with measured data available at room temperature.

  15. Effects of bone-specific physical activity, gender and maturity on tibial cross-sectional bone material distribution: a cross-sectional pQCT comparison of children and young adults aged 5-29 years.

    PubMed

    Rantalainen, Timo; Weeks, Benjamin K; Nogueira, Rossana C; Beck, Belinda R

    2015-03-01

    Growth is the opportune time to modify bone accrual. While bone adaptation is known to be dependent on local loading and consequent deformations (strain) of bone, little is known about the effects of sex, and bone-specific physical activity on location-specific cross-sectional bone geometry during growth. To provide more insight we examined bone traits at different locations around tibial cross sections, and along the tibia between individuals who vary in terms of physical activity exposure, sex, and pubertal status. Data from 304 individuals aged 5-29 years (172 males, 132 females) were examined. Peripheral quantitative computed tomography (pQCT) was applied at 4%, 14%, 38%, and 66% of tibial length. Maturity was established by estimating age at peak height velocity (APHV). Loading history was quantified with the bone-specific physical activity questionnaire (BPAQ). Comparisons, adjusted for height, weight and age were made between sex, maturity, and BPAQ tertile groups. Few to no differences were observed between sexes or BPAQ tertiles prior to APHV, whereas marked sexual dimorphism and differences between BPAQ tertiles were observed after APHV. Cross-sectional location-specific differences between BPAQ tertiles were not evident prior to APHV, whereas clear location-specificity was observed after APHV. In conclusion, the skeletal benefits of physical activity are location-specific in the tibia. The present results indicate that the peri- or post-pubertal period is likely a more favourable window of opportunity for enhancing cross-sectional bone geometry than pre-puberty. Increased loading during the peri-pubertal period may enhance the bone of both sexes. PMID:25465388

  16. Effectiveness of Choice Theory Connections: a cross-sectional and comparative analysis of California female inmates.

    PubMed

    Grills, Cheryl; Villanueva, Sandra; Anderson, Michelle; Corsbie-Massay, Charisse L; Smith, Bradley; Johnson, Lester; Owens, Kyri

    2015-06-01

    In the past 30 years, the rates of incarceration and recidivism for women in the United States have increased dramatically. Choice Theory® Connections (CTC) is a gender-tailored pre-release intervention program based on Choice Theory® (Glasser, 1999), and designed to achieve meaningful and sustainable cognitive and behavioral change. This evaluation examines CTC among 96 female participants in a California state prison enrolled in an introductory (n = 58) or advanced (n = 38) course. CTC significantly improved perceived stress, mindfulness, emotion regulation, impulsivity, and well-being on completion; effects were stronger for the introductory cohort, but significant effects also emerged for the advanced cohort. In addition, participants in the advanced cohort reported better scores at baseline, demonstrating the effects of prolonged engagement with the intervention. Results suggest that CTC can improve incarcerated women's well-being pre-release, a strong predictor of recidivism post-release. Further study and wider use of CTC are encouraged. PMID:24441032

  17. Evaluating the effect of risperidone on speech: A cross-sectional study.

    PubMed

    Sinha, Preeti; Vandana, V P; Lewis, Nikita Vincent; Jayaram, M; Enderby, Pamela

    2015-06-01

    Speech subsystems are susceptible to the effects of several factors including medications. The atypical antipsychotics can also adversely affect the speech because of its action on serotonin and dopamine neurotransmitters. The present study aims to analyze the speech characteristics associated with atypical antipsychotic risperidone. Speech of 92 patients on risperidone with or without trihexyphenidyl and/or clonazepam were compared with that of 31 persons who were not on any psychotropic medicines. Compared to control group, maximum phonation duration, sequential motion rate of diadochokinesia was reduced by about 3s and 1syllable/s respectively and s/z ratio was increased by 0.16 in patients with risperidone. Performance of larynx, lips and tongue sub-system and intelligibility of speech were also significantly reduced in risperidone group. Risperidone did impact the phonation and articulation sub-systems of speech mildly, which was independent of tardive dyskinesia and extrapyramidal symptoms. Randomized controlled prospective study looking into impact on speech and related effect on drug adherence, functioning and quality of life needs to be conducted with risperidone and other atypical antipsychotics. PMID:26013669

  18. Effects of air pollution on the respiratory health of children: a cross-sectional study

    SciTech Connect

    Spinaci, S.; Arossa, W.; Bugiani, M.; Natale, P.; Bucca, C.; de Candussio, G.

    1985-09-01

    To investigate the effects of air pollution on the respiratory health of children, a subject of some controversy, a comparative study was undertaken of 2,385 school children who lived in central urban, peripheral urban, and suburban areas. Daily monitoring of sulfur dioxide and total suspended particle concentrations in all areas showed that pollutant concentrations in central and peripheral urban areas were above commonly accepted safety levels for respiratory health, while concentrations in the suburban area were within acceptable limits. A questionnaire administered to each mother assessed environmental exposure to pollutants in the household, the occurrence of respiratory symptoms as well as lung diseases as diagnosed by a physician, and general information. Children were interviewed about smoking habits and any acute respiratory symptoms. Children also performed standard lung function tests. Results showed that children from both urban areas had lessened pulmonary function and a higher prevalence of bronchial secretion with common colds than did those from the suburban area. These differences persisted after corrections for exposure to indoor pollutants, active or passive smoking, socioeconomic status, and sex. Parental cigarette smoking was related to a fall in forced expiratory volume in 1 second and an increased incidence of acute respiratory illnesses and chronic cough in children. Although boys had higher lung volumes and lower air flow, regression analysis showed no significant influence of the interactions sex-geographic area and sex-smoking on lung function. It was concluded that air pollution has a significant effect on the respiratory health of children.

  19. The Effect of N2 Photoabsorption Cross Section Resolution on C2H6 Production in Titan’s Ionosphere

    NASA Astrophysics Data System (ADS)

    Luspay-Kuti, Adrienn; Mandt, Kathleen E.; Plessis, Sylvain; Greathouse, Thomas K.

    2014-11-01

    Titan’s rich organic chemistry begins with the photochemistry of only two molecules: N2 and CH4. The details on how higher-order hydrocarbons and nitriles are formed from these molecules have key implications for both the structure and evolution of Titan’s atmosphere, and for its surface-atmosphere interactions. Of high importance is the production of C2H6, which is a sink for CH4, and a main component in the polar lakes. Results of photochemical models, though, may be sensitive to the choice of input parameters, such as the N2 photoabsorption cross section resolution, as previously shown for nitrogen (Liang et al. (2007) ApJL 664, 115-118), and CH4 (Lavvas et al. (2011) Icarus 213, 233-251). Here we investigate the possibility of the same effect on the production rates of C2H6. We modeled production and loss rates, as well as mixing ratio and density profiles between an altitude of 600 and 1600 km for low and high resolution N2 cross sections via a coupled ion-neutral-thermal model (De La Haye et al. (2008) Icarus 197, 110-136; Mandt et al. (2012) JGR 117, E10006). Our results show a clear impact of photoabsorption cross section resolution used on all neutral and ion species contributing to C2H6 production. The magnitude of the influence varies amongst species. Ethane production profiles exhibit a significant increase with better resolution; a factor of 1.2 between 750 and 950 km, and a factor of 1.1 in the total column-integrated production rate. These values are lower limits, as additional reactions involving C2H5 not included in the model may also contribute to the production rates. The clear effect on C2H6 (which is not a parent molecule, nor does it bear nitrogen) may have important implications for other molecules in Titan’s atmosphere as well. The possible non-negligible impact of an isotope of nitrogen may argue for the inclusion of isotopes in photochemical models. For future analysis, development of a more efficient and streamlined model called

  20. Effect of Communication Skills Training on the Burnout of Nurses: A Cross-Sectional Study

    PubMed Central

    Darban, Fatemeh; Balouchi, Abbas; Narouipour, Abdullreza; Shahdadi, Hosein

    2016-01-01

    Introduction One of the factors influencing the burnout of nurses is their difficult and complicated relations with patients and other members of the medical team. Therefore, it is necessary that nurses to be trained on communication skills. Aim The present research aims to study the effect of communication skills training on the burnout of nurses. Materials and Methods The present research was an experimental study using pretest-posttest method. The subjects included 60 nurses working in Khatamolanbia Hospital in Iranshahr, Sistan and Baluchestan Province, Iran. The subjects were randomly divided into two groups. The required data and information were collected using Jackson and Maslach Burnout Inventory which was filled out by subjects in three steps including before the intervention, at the end of the second session, and one month after the intervention. The intervention included training on communication skills which was carried out for the intervention group as a 2-day workshop for 8 hours within a week. Results The findings showed that the mean score of frequency and intensity of burnout in the intervention group before the intervention, at the end of the intervention, and one month after the intervention was 39.3±6.2 and 61.1±8.0, 37.5±4.6 and 58.8±7.6, and 34.2±4.4 and 54.6±7.0, respectively. These changes suggest a significant decreasing trend (p=0.01). On the other hand, mean scores of burnout in the control group showed no significant difference in three steps (p<0.05). Conclusion Since communication skills training is an effective and inexpensive way for reducing the burnout among nurses, it is recommended that this approach to be taken into account by managers in order to reduce the burnout among nurses and improve the quality of healthcare services provided by them. PMID:27190832

  1. The effect of physical loading on calcaneus quantitative ultrasound measurement: a cross-section study

    PubMed Central

    2012-01-01

    Background Physical loading leads to a deformation of bone microstructure and may influence quantitative ultrasound (QUS) parameters. This study aims at evaluating the effect of physical loading on bone QUS measurement, and further, on the potential of diagnosing osteoporosis using QUS method under physical loading condition. Methods 16 healthy young females (control group) and 45 postmenopausal women (divided into 3 groups according to the years since menopause (YSM)) were studied. QUS parameters were measured at calcaneus under self-weight loading (standing) and no loading (sitting) conditions. Weight-normalized QUS parameter (QUS parameter measured under loading condition divided by the weight of the subject) was proposed to evaluate the influence of loading. T-test, One-Way analysis of variance (one way ANOVA) and receiver operating characteristic (ROC) analysis were applied for analysis. Results In QUS parameters, mainly normalized broadband ultrasound attenuation (nBUA), measured with loading significantly differed from those measured without loading (p < 0.05). The relative changes of weight-normalized QUS parameters on postmenopausal women with respect to premenopausal women under loading condition were larger than those on traditional QUS parameters measured without loading. In ROC analysis, weight-normalized QUS parameters showed their stronger discriminatory ability for menopause. Conclusions Physical loading substantially influenced bone QUS measurement (mainly nBUA). Weight-normalized QUS parameters can discriminate menopause more effectively. By considering the high relationship between menopause and osteoporosis, an inference was drawn that adding physical loading during measurement may be a probable way to improve the QUS based osteoporosis diagnosis. PMID:22584084

  2. Electron collisions with phenol: Total, integral, differential, and momentum transfer cross sections and the role of multichannel coupling effects on the elastic channel

    SciTech Connect

    Costa, Romarly F. da; Oliveira, Eliane M. de; Lima, Marco A. P.; Bettega, Márcio H. F.; Varella, Márcio T. do N.; Jones, Darryl B.; Brunger, Michael J.; Blanco, Francisco; Colmenares, Rafael; and others

    2015-03-14

    We report theoretical and experimental total cross sections for electron scattering by phenol (C{sub 6}H{sub 5}OH). The experimental data were obtained with an apparatus based in Madrid and the calculated cross sections with two different methodologies, the independent atom method with screening corrected additivity rule (IAM-SCAR), and the Schwinger multichannel method with pseudopotentials (SMCPP). The SMCPP method in the N{sub open}-channel coupling scheme, at the static-exchange-plus-polarization approximation, is employed to calculate the scattering amplitudes at impact energies ranging from 5.0 eV to 50 eV. We discuss the multichannel coupling effects in the calculated cross sections, in particular how the number of excited states included in the open-channel space impacts upon the convergence of the elastic cross sections at higher collision energies. The IAM-SCAR approach was also used to obtain the elastic differential cross sections (DCSs) and for correcting the experimental total cross sections for the so-called forward angle scattering effect. We found a very good agreement between our SMCPP theoretical differential, integral, and momentum transfer cross sections and experimental data for benzene (a molecule differing from phenol by replacing a hydrogen atom in benzene with a hydroxyl group). Although some discrepancies were found for lower energies, the agreement between the SMCPP data and the DCSs obtained with the IAM-SCAR method improves, as expected, as the impact energy increases. We also have a good agreement among the present SMCPP calculated total cross section (which includes elastic, 32 inelastic electronic excitation processes and ionization contributions, the latter estimated with the binary-encounter-Bethe model), the IAM-SCAR total cross section, and the experimental data when the latter is corrected for the forward angle scattering effect [Fuss et al., Phys. Rev. A 88, 042702 (2013)].

  3. Cross-Sectional Data Within 1 Year of the Fukushima Meltdown: Effect-Size of Predictors for Depression.

    PubMed

    Lebowitz, Adam Jon

    2016-01-01

    This cross-sectional study investigates effect sizes of depression predictors in a community close to the Fukushima, Japan nuclear reactor damaged by the 11 March, 2011 earthquake and tsunami. Subjects volunteered for assessment between December, 2011 and March, 2012. Of 466 individuals (351 female, mean age 60.4 year, SD = 14.0), 23 % of the female participants and 17 % of the male participants could be diagnosed with depression. The strongest predictors were house damage, age, income reduction, home water incursion, and casualty acquaintance. Education level, location during disaster, and workplace damage proved non-significant. The high number of retired/unemployed in the sample may have influenced outcome. Results suggest sampling influences the applicability of Conservation of Resources model to a disaster event. PMID:25820986

  4. Cross-Sectional Investigations on Epitaxial Silicon Solar Cells by Kelvin and Conducting Probe Atomic Force Microscopy: Effect of Illumination

    NASA Astrophysics Data System (ADS)

    Narchi, Paul; Alvarez, Jose; Chrétien, Pascal; Picardi, Gennaro; Cariou, Romain; Foldyna, Martin; Prod'homme, Patricia; Kleider, Jean-Paul; i Cabarrocas, Pere Roca

    2016-02-01

    Both surface photovoltage and photocurrent enable to assess the effect of visible light illumination on the electrical behavior of a solar cell. We report on photovoltage and photocurrent measurements with nanometer scale resolution performed on the cross section of an epitaxial crystalline silicon solar cell, using respectively Kelvin probe force microscopy and conducting probe atomic force microscopy. Even though two different setups are used, the scans were performed on locations within 100-μm distance in order to compare data from the same area and provide a consistent interpretation. In both measurements, modifications under illumination are observed in accordance with the theory of PIN junctions. Moreover, an unintentional doping during the deposition of the epitaxial silicon intrinsic layer in the solar cell is suggested from the comparison between photovoltage and photocurrent measurements.

  5. Cross-Sectional Investigations on Epitaxial Silicon Solar Cells by Kelvin and Conducting Probe Atomic Force Microscopy: Effect of Illumination.

    PubMed

    Narchi, Paul; Alvarez, Jose; Chrétien, Pascal; Picardi, Gennaro; Cariou, Romain; Foldyna, Martin; Prod'homme, Patricia; Kleider, Jean-Paul; I Cabarrocas, Pere Roca

    2016-12-01

    Both surface photovoltage and photocurrent enable to assess the effect of visible light illumination on the electrical behavior of a solar cell. We report on photovoltage and photocurrent measurements with nanometer scale resolution performed on the cross section of an epitaxial crystalline silicon solar cell, using respectively Kelvin probe force microscopy and conducting probe atomic force microscopy. Even though two different setups are used, the scans were performed on locations within 100-μm distance in order to compare data from the same area and provide a consistent interpretation. In both measurements, modifications under illumination are observed in accordance with the theory of PIN junctions. Moreover, an unintentional doping during the deposition of the epitaxial silicon intrinsic layer in the solar cell is suggested from the comparison between photovoltage and photocurrent measurements. PMID:26831693

  6. Effects of psychological stress on hypertension in middle-aged Chinese: a cross-sectional study.

    PubMed

    Hu, Bo; Liu, Xiaoyu; Yin, Sufeng; Fan, Hongmin; Feng, Fumin; Yuan, Juxiang

    2015-01-01

    We examined the effect and relative contributions of different types of stress on the risk of hypertension. Using cluster sampling, 5,976 community-dwelling individuals aged 40-60 were selected. Hypertension was defined according to the Seventh Report of the Joint National Committee, and general psychological stress was defined as experiencing stress at work or home. Information on known risk factors of hypertension (e.g., physical activity levels, food intake, smoking behavior) was collected from participants. Logistic regression analysis was used to determine the associations between psychological stress and hypertension, calculating population-attributable risks and 95% confidence intervals (CIs). General stress was significantly related to hypertension (odds ratio [OR] = 1.247, 95% CI [1.076, 1.446]). Additionally, after adjustment for all other risk factors, women showed a greater risk of hypertension if they had either stress at work or at home: OR = 1.285, 95% CI (1.027, 1.609) and OR = 1.231, 95% CI (1.001, 1.514), respectively. However, this increased risk for hypertension by stress was not found in men. General stress contributed approximately 9.1% (95% CI [3.1, 15.0]) to the risk for hypertension. Thus, psychological stress was associated with an increased risk for hypertension, although this increased risk was not consistent across gender. PMID:26043027

  7. Photoinitiated electron transfer to selected physisorbed alkyl bromides: The effects of alkyl chain length on dissociation cross sections

    SciTech Connect

    Khan, K.A.; Camillone, N. III; Osgood, R.M. Jr.

    1999-06-01

    We report the results of measurements of the cross section as a function of wavelength (351, 248, and 193 nm) for photoinitiated dissociative electron attachment to three normal alkyl bromides [CH{sub 3}(CH{sub 2}){sub n{minus}1}Br, n=1, 2, and 3] physisorbed on GaAs(110). Upon UV exposure, the molecules undergo C{endash}Br bond cleavage due to a substrate-mediated electron-transfer process. The cross sections for all three molecules increase monotonically with decreasing wavelength. Our results suggest a {approximately}1 eV higher threshold for dissociation of ethyl and propyl bromide than for methyl bromide. A simple model of the electron-transfer process is employed to estimate the peak per-electron cross section for dissociative attachment in the monolayer. We find that the cross sections for the physisorbed molecules are approximately five times smaller than those for gas-phase molecules, due to a reduction in the lifetime of the molecular anion in the vicinity of the surface. In addition, we also find an increase in cross section with chain length very similar to that observed in the gas phase; the gas-phase behavior has been explained by an increase in the anion lifetime with chain length. Our results suggest that while quenching of the molecular anion at the surface is important, it does not eliminate the progression of anion lifetime with chain length. {copyright} {ital 1999 American Institute of Physics.}

  8. Investigation of the effects of nuclear level density parameters on the cross sections for the 234U(γ,f) reaction

    NASA Astrophysics Data System (ADS)

    Pekdogan, Hakan; Aydin, Abdullah; Hakki Sarpun, Ismail

    2015-07-01

    In this study, we have investigated the effects of nuclear level density parameters on the cross sections for the 234U(γ,f) reaction up to 20 MeV. The cross sections on 234U(γ,f) reaction were calculated for different level density models using the TALYS 1.6 code. First, it was determined the level density model that was the closest to the experimental data. Secondly, cross sections obtained for different level density parameters of this model were compared with experimental data from the EXFOR database. Thus it was determined the best level density parameter fit to experimental data.

  9. Neutrino flux predictions for cross section measurements

    SciTech Connect

    Hartz, Mark

    2015-05-15

    Experiments that measure neutrino interaction cross sections using accelerator neutrino sources require a prediction of the neutrino flux to extract the interaction cross section from the measured neutrino interaction rate. This article summarizes methods of estimating the neutrino flux using in-situ and ex-situ measurements. The application of these methods by current and recent experiments is discussed.

  10. Absolute partial photoionization cross sections of ozone.

    SciTech Connect

    Berkowitz, J.; Chemistry

    2008-04-01

    Despite the current concerns about ozone, absolute partial photoionization cross sections for this molecule in the vacuum ultraviolet (valence) region have been unavailable. By eclectic re-evaluation of old/new data and plausible assumptions, such cross sections have been assembled to fill this void.

  11. A cross sectional study of oral submucous fibrosis in central India and the effect of local triamcinolone therapy.

    PubMed

    Ameer, N T; Shukla, Rakesh Kumar

    2012-09-01

    The use of processed arecanut is on the increase. In the impending danger of increased occurrence of oral submucous fibrosis and subsequent oral cancer following this habit is colossal. So an attempt is made to clinically evaluate the condition and to evaluate the effect of triamcinolone on this condition. Using the clinical data collected from the patients presenting in the ENT OPD of NSCB Medical College Hospital, Jabalpur, a cross sectional study was done and the effect of intralesional triamcinolone on this condition is noted by biweekly submucosal injections of 40 mg triamcinolone for 12 weeks and followed up for 1 year. The effect of therapy was evaluated subjectively by improvement in symptoms and objectively by increase in mouth opening. The age of occurrence and sex predilection also showed a significant change with more young males being affected by the condition. There was no significant correlation between effect of triamcinolone therapy and duration of addiction but a significant correlation (P < 0.0001) was noted with the frequency of addiction per day. A significant improvement in mouth opening is observed following local triamcinolone therapy. The results imply that the exposure and the frequency of chewing habits, and not mere the duration that is significant in producing the condition and affecting the treatment outcome. Local triamcinolone therapy has good effect in the initial stages of the disease. The fact that more youngsters are being affected needs serious consideration. PMID:23998027

  12. Quality of life in colon cancer patients with skin side effects: preliminary results from a monocentric cross sectional study

    PubMed Central

    2010-01-01

    Background Epidermal growth factor receptor inhibitors are widely prescribed anticancer drugs. Patients treated commonly develop dermatologic adverse drugs reactions, but rarely they are involved in systematic evaluation of their quality of life. This monocentric cross sectional study is carried out to assess quality of life in colon cancer patients experienced skin side effects due to anti epidermal growth factor receptor inhibitors therapy. Methods Consecutive patients with skin side effects to therapy treated at Fondazione Poliambulanza were enrolled in this study. Quality of life was evaluated with the Italian validated version of Skindex-29 questionnaire, exploring three dimensions: symptoms, emotional, and physical functioning. Skindex-29 was administered one time between the eighth and the twelfth week of the treatment. Results Forty-five consecutive patients, mainly with metastatic colon cancer (29 female, 16 male), with an average age of 59.31 years (ranging from 34-78) were included in the study and analyzed. Patients showed a great impact of skin side effects on symptoms (mean 43), followed by emotional (mean 30), and functioning (mean 26) scales. In general women, the 55-65 age class, and patients with partial remission reported the worst quality of life. Conclusions Epidermal growth factor receptor inhibitors' skin side effects have an important impact on quality of life in advanced colon cancer patients; symptoms scale is the most effect respect to emotional and functioning scales. PMID:20398332

  13. Effect of Spinal Cord Injury on Quality of Life of Affected Soldiers in India: A Cross-Sectional Study

    PubMed Central

    Gupta, Bhawna

    2016-01-01

    Study Design A prospective cross-sectional study with convenience sampling approach was done to assess quality of life (QoL) in 100 soldiers and veterans affected by spinal cord injury (SCI). Purpose SCI affects almost every aspect of the life of an affected individual. This study was done to measure the impact of SCI on QoL of affected soldiers and veterans using the WHOQOL-BREF questionnaire. Overview of Literature The devastating effect of SCI on QoL is well known. However, this study is unique in that it includes soldiers and veterans, who constitute a large, but excluded, cohort in most demographic studies. Methods A cross-sectional study was done at two SCI rehabilitation centres of the Indian armed forces. Data was collected by face-to-face interviews from 100 patients, which included both sociodemographic data as well as all the questions included in WHOQOL-BREF questionnaire. Statistical analysis was performed using SPSS software. Results Age and marital status did not have any influence on QoL. Level of injury (paraplegic or quadriplegic), level of education and presence of other medical co-morbidities had the most significant influence on QoL. Presence of other medical co-morbidities had a negative influence on QoL. Conclusions Identification of factors having a positive and negative influence on QoL help in formulating measures and policies that positively influence the QoL following SCI in soldiers. Future longitudinal studies with larger sample sizes and assessment of additional variables in addition to WHOQOL-BREF, like presence/absence of secondary complications, are required to bring about policy changes to provide SCI patients with additional support and increased access to equipment or lifestyle interventions. PMID:27114767

  14. A cross-sectional analysis of dioxins and health effects in municipal and private waste incinerator workers in Japan

    PubMed Central

    YAMAMOTO, Kenya; KUDO, Mitsuhiro; ARITO, Heihachiro; OGAWA, Yasutaka; TAKATA, Tsutomu

    2015-01-01

    This cross-sectional study was intended to examine health effects of 678 male workers employed during an 8-yr period from 2000 to 2007 at 36 municipal and private waste incineration plants in Japan. Blood samples were obtained for analysis of concentrations of dioxins including coplanar polychlorinated biphenyls (coplanar PCBs) and evaluation of health effects. Health effects including diabetes were surveyed via a physician’s interview or clinical data from blood samples. There was a certain difference in serum concentrations of polychlorinated dibenzofurans (PCDFs) between the incinerator workers and Japanese general population, although no differences in the concentrations of total dioxins or polychlorinated dibenzo-p-dioxins (PCDDs) were found between the two groups. A few positive correlations between serum levels of PCDDs and PCDFs and the results of laboratory and physiological tests were found, but coplanar PCBs showed significant relations with 14 parameters of the tests. The background serum levels of PCDDs, PCDFs and total dioxins were significantly associated with the prevalence of diabetes. No essential differences in serum concentrations of total dioxins and in prevalence of diabetes between our subjects and the general population suggested that the incinerator workers were marginally exposed to dioxins in the workplace without any recognizable adverse health effects. PMID:26212412

  15. A cross-sectional analysis of dioxins and health effects in municipal and private waste incinerator workers in Japan.

    PubMed

    Yamamoto, Kenya; Kudo, Mitsuhiro; Arito, Heihachiro; Ogawa, Yasutaka; Takata, Tsutomu

    2015-01-01

    This cross-sectional study was intended to examine health effects of 678 male workers employed during an 8-yr period from 2000 to 2007 at 36 municipal and private waste incineration plants in Japan. Blood samples were obtained for analysis of concentrations of dioxins including coplanar polychlorinated biphenyls (coplanar PCBs) and evaluation of health effects. Health effects including diabetes were surveyed via a physician's interview or clinical data from blood samples. There was a certain difference in serum concentrations of polychlorinated dibenzofurans (PCDFs) between the incinerator workers and Japanese general population, although no differences in the concentrations of total dioxins or polychlorinated dibenzo-p-dioxins (PCDDs) were found between the two groups. A few positive correlations between serum levels of PCDDs and PCDFs and the results of laboratory and physiological tests were found, but coplanar PCBs showed significant relations with 14 parameters of the tests. The background serum levels of PCDDs, PCDFs and total dioxins were significantly associated with the prevalence of diabetes. No essential differences in serum concentrations of total dioxins and in prevalence of diabetes between our subjects and the general population suggested that the incinerator workers were marginally exposed to dioxins in the workplace without any recognizable adverse health effects. PMID:26212412

  16. The effects of newly measured cross sections in hydrogen on the production of secondary nuclei during the propagation of cosmic rays through interstellar H

    NASA Technical Reports Server (NTRS)

    Webber, W. R.; Gupta, M.; Koch-Miramond, L.; Masse, P.

    1985-01-01

    The cross sections of six important cosmic ray source nuclei in hydrogen at several energies between 300 and 1800 MeV/nuc were measured. Significant differences, sometimes exceeding 50%, exist between these new measurements and the earlier semiempirical predictions, and a new set of semiempirical formulae are being determined that better describe this fragmentation. New cross sections were obtained so that the systematics of their effects on cosmic ray propagation through interstellar hydrogen can be examined.

  17. International Evaluation of Neutron Cross Section Standards

    NASA Astrophysics Data System (ADS)

    Carlson, A. D.; Pronyaev, V. G.; Smith, D. L.; Larson, N. M.; Chen, Zhenpeng; Hale, G. M.; Hambsch, F.-J.; Gai, E. V.; Oh, Soo-Youl; Badikov, S. A.; Kawano, T.; Hofmann, H. M.; Vonach, H.; Tagesen, S.

    2009-12-01

    Neutron cross section standards are the basis for the determination of most neutron cross sections. They are used for both measurements and evaluations of neutron cross sections. Not many cross sections can be obtained absolutely - most cross sections are measured relative to the cross section standards and converted using evaluations of the standards. The previous complete evaluation of the neutron cross section standards was finished in 1987 and disseminated as the NEANDC/INDC and ENDF/B-VI standards. R-matrix model fits for the light elements and non-model least-squares fits for all the cross sections in the evaluation were the basis of the combined fits for all of the data. Some important reactions and constants are not standards, but they assist greatly in the determination of the standard cross sections and reduce their uncertainties - these data were also included in the combined fits. The largest experimental database used in the evaluation was prepared by Poenitz and included about 400 sets of experimental data with covariance matrices of uncertainties that account for all cross-energy, cross-reaction and cross-material correlations. For the evaluation GMA, a least-squares code developed by Poenitz, was used to fit all types of cross sections (absolute and shape), their ratios, spectrum-averaged cross sections and thermal constants in one full analysis. But, the uncertainties derived in this manner, and especially those obtained in the R-matrix model fits, have been judged to be too low and unrealistic. These uncertainties were substantially increased prior to their release in the recommended data files of 1987. Modified percentage uncertainties were reassigned by the United States Cross Section Evaluation Working Group's Standards Subcommittee for a wide range of energies, and no covariance (or correlation) matrices were supplied at that time. The need to re-evaluate the cross section standards is based on the appearance of a significant amount of precise

  18. Effects of Stabilization Exercise Using a Ball on Mutifidus Cross-Sectional Area in Patients with Chronic Low Back Pain

    PubMed Central

    Chung, SinHo; Lee, JuSang; Yoon, JangSoon

    2013-01-01

    The purpose of this study was to compare the effects of lumbar stabilization exercises using balls to the effects of general lumbar stabilization exercises with respect to changes in the cross section of the multifidus (MF), weight bearing, pain, and functional disorders in patients with non-specific chronic low back pain. Twelve patients participated in either a 8 week (3 days per week) stabilization exercise program using balls and control group (n = 12). The computer tomography (CT) was used to analyze MF cross-sectional areas (CSA) and Tetrax balancing scale was used to analyze left and right weight bearing differences. Both groups had significant changes in the CSA of the MF by segment after training (p < 0.05) and the experimental group showed greater increases at the L4 (F = 9.854, p = 0.005) and L5 (F = 39. 266, p = 0.000). Both groups showed significant decreases in weight bearing, from 9.25% to 5.83% in the experimental group and from 9.33% to 4.25% in the control group (p < 0.05), but did not differ significantly between the two groups. These results suggests that stabilization exercises using ball can increases in the CSA of the MF segments, improvement in weight bearing, pain relief, and recovery from functional disorders, and the increases in the CSA of the MF of the L4 and L5 segments for patients with low back pain. Key Points Compared with the stabilization exercise using a ball and general stabilization exercise increased the CSA of the MF, weight bearing, pain, and functional ability in patients with low back pain. We verified that increases in the CSA of the MF of the L4 and L5 segments and functional ability during the stabilization exercise using a ball. The stabilization exercise using a ball was shown to be an effective exercise method for patients with low back pain in a rehabilitation program by increasing functional ability and the CSA of the MF. PMID:24149162

  19. Nucleon-Nucleon Total Cross Section

    NASA Technical Reports Server (NTRS)

    Norbury, John W.

    2008-01-01

    The total proton-proton and neutron-proton cross sections currently used in the transport code HZETRN show significant disagreement with experiment in the GeV and EeV energy ranges. The GeV range is near the region of maximum cosmic ray intensity. It is therefore important to correct these cross sections, so that predictions of space radiation environments will be accurate. Parameterizations of nucleon-nucleon total cross sections are developed which are accurate over the entire energy range of the cosmic ray spectrum.

  20. Cross Section Evaluations for Arsenic Isotopes

    SciTech Connect

    Pruet, J; McNabb, D P; Ormand, W E

    2005-03-10

    The authors present an evaluation of cross sections describing reactions with neutrons incident on the arsenic isotopes with mass numbers 75 and 74. Particular attention is paid to (n,2n) reactions. The evaluation for {sup 75}As, the only stable As isotope, is guided largely by experimental data. Evaluation for {sup 74}As is made through calculations with the EMPIRE statistical-model reaction code. Cross sections describing the production and destruction of the 26.8 ns isomer in {sup 74}As are explicitly considered. Uncertainties and covariances in some evaluated cross sections are also estimated.

  1. Health effects of perceived racial and religious bullying among urban adolescents in China: a cross-sectional national study.

    PubMed

    Pan, Stephen W; Spittal, Patricia M

    2013-07-01

    Research concerning ethnocultural bullying and adolescent health in China remains extremely limited. This study among Chinese urban adolescents examines associations between ethnocultural bullying and eight health-related outcomes: suicidal ideation, suicide planning, depressive symptomology, anxiety symptomatology, fighting, injury intentionally inflicted by another, smoking and moderate/heavy alcohol consumption. Data were obtained from the World Health Organisation's 2003 Chinese Global School-based Health Survey, a cross-sectional national survey of urban adolescents in four Chinese cities. The analytic sample size was n = 8182, which represented a sampling frame of 769,835 adolescents. Statistical analysis was conducted using generalised linear mixed effects models and sampling weights. Prevalence of ethnocultural bullying was significantly higher in Urumqi, Xinjiang province (2.08%) compared with Beijing municipality (0.72%) or Wuhan, Hubei province (0.67%). Compared to participants who were not bullied, religious bullying victimisation was significantly associated with suicidal ideation, injury intentionally inflicted by another and depressive symptomology. Racial bullying victimisation was significantly associated with suicidal ideation, injury intentionally inflicted by another and among females but not males, depressive symptomology. Health effects of ethnocultural bullying appear to be distinct from that of bullying in general. Additional research on ethnocultural adolescent health issues in China is warranted. PMID:23713464

  2. Relationship between efficiency and clinical effectiveness indicators in an adjusted model of resource consumption: a cross-sectional study

    PubMed Central

    2013-01-01

    Background Adjusted clinical groups (ACG®) have been widely used to adjust resource distribution; however, the relationship with effectiveness has been questioned. The purpose of the study was to measure the relationship between efficiency assessed by ACG® and a clinical effectiveness indicator in adults attended in Primary Health Care Centres (PHCs). Methods Research design: cross-sectional study. Subjects: 196, 593 patients aged >14 years in 13 PHCs in Catalonia (Spain). Measures: Age, sex, PHC, basic care team (BCT), visits, episodes (diagnoses), and total direct costs of PHC care and co-morbidity as measured by ACG® indicators: Efficiency indices for costs, visits, and episodes (costs EI, visits EI, episodes EI); a complexity or risk index (RI); and effectiveness measured by a general synthetic index (SI). The relationship between EI, RI, and SI in each PHC and BCT was measured by multiple correlation coefficients (r). Results In total, 56 of the 106 defined ACG® were present in the study population, with five corresponding to 44.5% of the patients, 11 to 68.0% of patients, and 30 present in less than 0.5% of the sample. The RI in each PHC ranged from 0.9 to 1.1. Costs, visits, and episodes had similar trends for efficiency in six PHCs. There was moderate correlation between costs EI and visits EI (r = 0.59). SI correlation with episodes EI and costs EI was moderate (r = 0.48 and r = −0.34, respectively) and was r = −0.14 for visits EI. Correlation between RI and SI was r = 0.29. Conclusions The Efficiency and Effectiveness ACG® indicators permit a comparison of primary care processes between PHCs. Acceptable correlation exists between effectiveness and indicators of efficiency in episodes and costs. PMID:24139144

  3. Effect of Lipophilic and Hydrophilic Statins on Breast Cancer Risk in Thai Women: A Cross-sectional Study

    PubMed Central

    Anothaisintawee, Thunyarat; Udomsubpayakul, Umaporn; McEvoy, Mark; Lerdsitthichai, Panuwat; Attia, John; Thakkinstian, Ammarin

    2016-01-01

    Background: Statins are proposed as a chemoprevention agent for breast cancer due to their anti-inflammatory effect. The effects of lipophilic and hydrophilic statins on breast cancer risk might be different due to their different pharmacologic properties. Therefore, this study aimed to assess a casual-effect of lipophilic and hydrophilic statins on breast cancer risk using a counterfactual framework approach. Methods: A cross-sectional study of 15,718 women who were screened for breast cancer at Mammographic center, Ramathibodi Hospital, Bangkok, Thailand, was conducted during September 2011 to 2012. A counterfactual framework approach was applied to assess causal effects of treatments (i.e., lipophilic and hydrophilic statins) on outcome (i.e. breast cancer). Multi-logit and logistic regression models were used for treatment and outcome models, respectively. An inverse probability weight regression analysis (IPWRA) was then applied to estimate potential outcome mean (POM) and average treatment effect (ATE) by combining the outcome and treatment models. Results: Breast cancer risks were 0.0072 (95% CI: 0.0055, 0.0089), 0.0051 (95% CI: 0.0008, 0.0095), and 0.0038 (95% CI: 0.002, 0.0056) for non-statin users, hydrophilic, and lipophilic statin users, respectively. The estimated risk differences were -0.0021 (95% CI: -0.0067, 0.0026) and -0.0034 (95% CI: -0.0059, -0.0009) for hydrophilic and lipophilic statins respectively. The number needed to treat for hydrophilic and lipophilic statins were 2.1 (95% CI: -2.6, 6.7) and 3.4 (95% CI: 1.0, 5.9) per 1000 subjected, respectively. Conclusions: Our results suggested that using lipophilic statin could significantly reduce risk of breast cancer in Thai women. PMID:27326260

  4. Neutronic Cross Section Calculations on Fluorine Nucleus

    NASA Astrophysics Data System (ADS)

    Kara, A.; Tel, E.

    2013-06-01

    Certain light nuclei such as Lithium (Li), Beryllium (Be), Fluorine (F) (which are known as FLİBE) and its molten salt compounds (LiF, BeF2 and NaF) can serve as a coolant which can be used at high temperatures without reaching a high vapor pressure. These molten salt compounds are also a good neutron moderator. In this study, cross sections of neutron induced reactions have been calculated for fluorine target nucleus. The new calculations on the excitation functions of 19F( n, 2n), 19F( n, p), 19F( n, xn), 19F( n, xp) have been made. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the full exciton model and the cascade exciton model. The equilibrium effects are calculated according to the Weisskopf-Ewing model. Also in the present work, the ( n, 2n) and ( n, p) reaction cross sections have calculated by using evaluated empirical formulas developed by Tel et al. at 14-15 MeV energy. The multiple pre-equilibrium mean free path constant from internal transition have been investigated for 19F nucleus. The obtained results have been discussed and compared with the available experimental data.

  5. A nuclear cross section data handbook

    SciTech Connect

    Fisher, H.O.M.

    1989-12-01

    Isotopic information, reaction data, data availability, heating numbers, and evaluation information are given for 129 neutron cross-section evaluations, which are the source of the default cross sections for the Monte Carlo code MCNP. Additionally, pie diagrams for each nuclide displaying the percent contribution of a given reaction to the total cross section are given at 14 MeV, 1 MeV, and thermal energy. Other information about the evaluations and their availability in continuous-energy, discrete-reaction, and multigroup forms is provided. The evaluations come from ENDF/B-V, ENDL85, and the Los Alamos Applied Nuclear Science Group T-2. Graphs of all neutron and photon production cross-section reactions for these nuclides have been categorized and plotted. 21 refs., 5 tabs.

  6. The radar cross section of dielectric disks

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1982-01-01

    A solution is presented for the backscatter (nonstatic) radar cross section of dielectric disks of arbitrary shape, thickness and dielectric constant. The result is obtained by employing a Kirchhoff type approximation to obtain the fields inside the disk. The internal fields induce polarization and conduction currents from which the scattered fields and the radar cross section can be computed. The solution for the radar cross section obtained in this manner is shown to agree with known results in the special cases of normal incidence, thin disks and perfect conductivity. The solution can also be written as a product of the reflection coefficient of an identically oriented slab times the physical optics solution for the backscatter cross section of a perfectly conducting disk of the same shape. This result follows directly from the Kirchhoff type approximation without additional assumptions.

  7. Bibliography of photoabsorption cross-section data

    NASA Technical Reports Server (NTRS)

    Hudson, R. D.; Kieffer, L. J.

    1970-01-01

    This bibliography contains only references which report a measured or calculated photoabsorption cross section (relative or normalized) in regions of continuous absorption. The bibliography is current as of January 1, 1970.

  8. Absorption cross section of canonical acoustic holes

    SciTech Connect

    Crispino, Luis C. B.; Oliveira, Ednilton S.; Matsas, George E. A.

    2007-11-15

    We compute numerically the absorption cross section of a canonical acoustic hole for sound waves with arbitrary frequencies. Our outputs are in full agreement with the expected low- and high-frequency limits.

  9. MODELING AND FISSION CROSS SECTIONS FOR AMERICIUM.

    SciTech Connect

    ROCHMAN, D.; HERMAN, M.; OBLOZINSKY, P.

    2005-05-01

    This is the final report of the work performed under the LANL contract on the modeling and fission cross section for americium isotopes (May 2004-June 2005). The purpose of the contract was to provide fission cross sections for americium isotopes with the nuclear reaction model code EMPIRE 2.19. The following work was performed: (1) Fission calculations capability suitable for americium was implemented to the EMPIRE-2.19 code. (2) Calculations of neutron-induced fission cross sections for {sup 239}Am to {sup 244g}Am were performed with EMPIRE-2.19 for energies up to 20 MeV. For the neutron-induced reaction of {sup 240}Am, fission cross sections were predicted and uncertainties were assessed. (3) Set of fission barrier heights for each americium isotopes was chosen so that the new calculations fit the experimental data and follow the systematics found in the literature.

  10. Effect of the crystallinity of silver nanoparticles on surface plasmon resonance induced enhancement of effective absorption cross-section of dyes

    NASA Astrophysics Data System (ADS)

    Tanvi, Mahajan, Aman; Bedi, R. K.; Kumar, Subodh; Saxena, Vibha; Aswal, D. K.

    2015-02-01

    The effective absorption cross-section of dye, and therefore, the efficiency of dye-sensitized solar cell can be increased by surface plasmon resonance (SPR) of metal nanoparticles with enhanced dephasing time. Further, the dephasing time is proportional to the enhancement factor of electric field in the vicinity of nanoparticle surface, and is governed by size, shape, and dielectric constant of surrounding medium. In this paper, we demonstrate that crystallinity of silver nanoparticles plays an important role in enhancing the dephasing time of SPR. Our theoretical formulation indicates that the dephasing time is higher for single crystalline silver nanoparticles as compared to that of polycrystalline nanoparticles, which is attributed to the presence of scattering centers in the latter. This suggests that single crystalline silver nanoparticles are interesting candidates for the enhancement of effective absorption cross-section of dyes. In order to validate our theoretical formulation, we have synthesized single crystalline and polycrystalline silver nanoparticles and studied their effect on absorption cross-section of N719 dye. We observed that dye incorporated with single crystalline silver nanoparticles showed a significant enhancement as compared to polycrystalline silver nanoparticles (24.42% in solution, 21.01% in thin film form in single crystalline silver nanoparticles while 8.52% in solution, 7.97% in thin film form in polycrystalline silver nanoparticles, respectively).

  11. Effect of Media Use on HIV-Related Stigma in Sub-Saharan Africa: A Cross-Sectional Study

    PubMed Central

    Bekalu, Mesfin Awoke; Eggermont, Steven; Ramanadhan, Shoba; Viswanath, Kasisomayajula

    2014-01-01

    It is known that HIV-related stigma hinders prevention efforts. Previous studies have documented that HIV-related stigma may be associated with socioeconomic and socioecological factors. Mass media use may moderate this association, but there is limited research addressing that possibility. In this study, based on cross-sectional data pooled from the 2006–2011 Demographic and Health Surveys of 11 sub-Saharan African countries (N = 204,343), we investigated the moderating effects of exposure to mass media on HIV-related stigma. Hierarchical regression analysis indicated that HIV-related stigma tends to be higher among rural residents and individuals with low levels of education and HIV knowledge, as well as those who do not know people living with HIV. Media use was generally associated with low levels of HIV-related stigma, and attenuated the gap between individuals with high and low educational levels. However, the effect of mass media was found to be stronger among urbanites rather than among rural residents, which could lead to a widening gap between the two groups in endorsement of HIV-related stigma. The implication of this study regarding the effect of media use on HIV-related stigma in sub-Saharan Africa is twofold: 1) mass media may have the potential to minimize the gap in HIV-related stigma between individuals with high and low educational levels, and hence future efforts of reducing HIV-related stigma in the region may benefit from utilizing media; 2) due perhaps to low media penetration to rural sub-Saharan Africa, mass media could have the unintended effect of widening the urban-rural gap further unless other more customized and rural-focused communication interventions are put in place. PMID:24945251

  12. Effect of media use on HIV-related stigma in Sub-Saharan Africa: a cross-sectional study.

    PubMed

    Bekalu, Mesfin Awoke; Eggermont, Steven; Ramanadhan, Shoba; Viswanath, Kasisomayajula

    2014-01-01

    It is known that HIV-related stigma hinders prevention efforts. Previous studies have documented that HIV-related stigma may be associated with socioeconomic and socioecological factors. Mass media use may moderate this association, but there is limited research addressing that possibility. In this study, based on cross-sectional data pooled from the 2006-2011 Demographic and Health Surveys of 11 sub-Saharan African countries (N = 204,343), we investigated the moderating effects of exposure to mass media on HIV-related stigma. Hierarchical regression analysis indicated that HIV-related stigma tends to be higher among rural residents and individuals with low levels of education and HIV knowledge, as well as those who do not know people living with HIV. Media use was generally associated with low levels of HIV-related stigma, and attenuated the gap between individuals with high and low educational levels. However, the effect of mass media was found to be stronger among urbanites rather than among rural residents, which could lead to a widening gap between the two groups in endorsement of HIV-related stigma. The implication of this study regarding the effect of media use on HIV-related stigma in sub-Saharan Africa is twofold: 1) mass media may have the potential to minimize the gap in HIV-related stigma between individuals with high and low educational levels, and hence future efforts of reducing HIV-related stigma in the region may benefit from utilizing media; 2) due perhaps to low media penetration to rural sub-Saharan Africa, mass media could have the unintended effect of widening the urban-rural gap further unless other more customized and rural-focused communication interventions are put in place. PMID:24945251

  13. Shuttle orbiter radar cross-sectional analysis

    NASA Technical Reports Server (NTRS)

    Cooper, D. W.; James, R.

    1979-01-01

    Theoretical and model simulation studies on signal to noise levels and shuttle radar cross section are described. Pre-mission system calibrations, system configuration, and postmission system calibration of the tracking radars are described. Conversion of target range, azimuth, and elevation into radar centered east north vertical position coordinates are evaluated. The location of the impinging rf energy with respect to the target vehicles body axis triad is calculated. Cross section correlation between the two radars is presented.

  14. Path forward for dosimetry cross sections

    SciTech Connect

    Griffin, P.J.; Peters, C.D.

    2011-07-01

    In the 1980's the dosimetry community embraced the need for a high fidelity quantification of uncertainty in nuclear data used for dosimetry applications. This led to the adoption of energy-dependent covariance matrices as the accepted manner of quantifying the uncertainty data. The trend for the dosimetry community to require high fidelity treatment of uncertainty estimates has continued to the current time where requirements on nuclear data are codified in standards such as ASTM E 1018. This paper surveys the current state of the dosimetry cross sections and investigates the quality of the current dosimetry cross section evaluations by examining calculated-to-experimental ratios in neutron benchmark fields. In recent years more nuclear-related technical areas are placing an emphasis on uncertainty quantification. With the availability of model-based cross sections and covariance matrices produced by nuclear data codes, some nuclear-related communities are considering the role these covariance matrices should play. While funding within the dosimetry community for cross section evaluations has been very meager, other areas, such as the solar-related astrophysics community and the US Nuclear Criticality Safety Program, have been supporting research in the area of neutron cross sections. The Cross Section Evaluation Working Group (CSEWG) is responsible for the creation and maintenance of the ENDF/B library which has been the mainstay for the reactor dosimetry community. Given the new trends in cross section evaluations, this paper explores the path forward for the US nuclear reactor dosimetry community and its use of the ENDF/B cross-sections. The major concern is maintenance of the sufficiency and accuracy of the uncertainty estimate when used for dosimetry applications. The two major areas of deficiency in the proposed ENDF/B approach are: 1) the use of unrelated covariance matrices in ENDF/B evaluations and 2) the lack of 'due consideration' of experimental data

  15. Ultraviolet absorption cross sections of hydrogen peroxide

    NASA Technical Reports Server (NTRS)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  16. QuickSite Cross Section Processing

    Energy Science and Technology Software Center (ESTSC)

    2003-05-27

    This AGEM-developed system produces cross sections by inputting data in both standard and custom file formats and outputting a graphic file that can be printed or further modified in a commercial graphic program. The system has evolved over several years in order to combine and visualize a changing set of field data more rapidly than was possible with commercially available cross section software packages. It uses some commercial packages to produce the input and tomore » modify the output files. Flexibility is provided by a dynamic set of programs that are customized to accept varying input and accomodate varying output requirements. There are two basic types of routines: conversion routines and cross section generation routines. The conversion routines convery various data files to logger file format which is compatible with a standard file format for LogPlot 98, a commonly used commercial log plotting program. The cross section routines generate cross sections and apply topography to these cross sections. All of the generation routines produce a standard graphic DXF file, which is the format used in AutoCAD and can then be modified in a number of available graphics programs.« less

  17. Predicting the Total Charm Cross Section

    SciTech Connect

    Vogt, R

    2008-05-29

    We discuss the energy dependence of the total charm cross section and some of its theoretical uncertainties including the quark mass, scale choice and the parton densities. Extracting the total charm cross section from data is a non-trivial task. To go from a finite number of measured D mesons in a particular decay channel to the total c{bar c} cross section one must: divide by the branching ratio for that channel; correct for the luminosity, {sigma}{sub D} = N{sub D}/Lt; extrapolate to full phase space from the finite detector acceptance; divide by two to get the pair cross section from the single Ds; and multiply by a correction factor to account for unmeasured charm hadrons. Early fixed-target data were at rather low p{sub T}, making the charm quark mass the most relevant scale. At proton and ion colliders, although the RHIC experiments can access the full pT range and thus the total cross section, the data reach rather high p{sub T}, p{sub T} >> m, making p{sub T} (m{sub T}) the most relevant scale. Here we focus on the total cross section calculation where the quark mass is the only relevant scale.

  18. About the Effect of Control on Flutter and Post-Flutter of a Supersonic/Hypersonic Cross-Sectional Wing

    NASA Technical Reports Server (NTRS)

    Marzocca, Piergiovanni; Librescu, Liviu; Silva, Walter A.

    2000-01-01

    The control of the flutter instability and the conversion of the dangerous character of the flutter instability boundary into the undangerous one of a cross-sectional wing in a supersonic/hypersonic flow field is presented. The objective of this paper is twofold: i) to analyze the implications of nonlinear unsteady aerodynamics and physical nonlinearities on the character of the instability boundary in the presence of a control capability, and ii) to outline the effects played in the same respect by some important parameters of the aeroelastic system. As a by-product of this analysis, the implications of the active control on the linearized flutter behavior of the system are captured and emphasized. The bifurcation behavior of the open/closed loop aeroelastic system in the vicinity of the flutter boundary is studied via the use of a new methodology based on the Liapunov First Quantity. The expected outcome of this study is: a) to greatly enhance the scope and reliability of the aeroelastic analysis and design criteria of advanced supersonic/hypersonic flight vehicles and, b) provide a theoretical basis for the analysis of more complex nonlinear aeroelastic systems.

  19. Geometrical and band-structure effects on phonon-limited hole mobility in rectangular cross-sectional germanium nanowires

    NASA Astrophysics Data System (ADS)

    Tanaka, H.; Mori, S.; Morioka, N.; Suda, J.; Kimoto, T.

    2014-12-01

    We calculated the phonon-limited hole mobility in rectangular cross-sectional [001], [110], [111], and [112]-oriented germanium nanowires, and the hole transport characteristics were investigated. A tight-binding approximation was used for holes, and phonons were described by a valence force field model. Then, scattering probability of holes by phonons was calculated taking account of hole-phonon interaction atomistically, and the linearized Boltzmann's transport equation was solved to calculate the hole mobility at low longitudinal field. The dependence of the hole mobility on nanowire geometry was analyzed in terms of the valence band structure of germanium nanowires, and it was found that the dependence was qualitatively reproduced by considering an average effective mass and the density of states of holes. The calculation revealed that [110] germanium nanowires with large height along the [001] direction show high hole mobility. Germanium nanowires with this geometry are also expected to exhibit high electron mobility in our previous work, and thus they are promising for complementary metal-oxide-semiconductor (CMOS) applications.

  20. Effect of antiepileptic drug therapy on thyroid hormones among adult epileptic patients: An analytical cross-sectional study

    PubMed Central

    Adhimoolam, Mangaiarkkarasi; Arulmozhi, Ranjitha

    2016-01-01

    Objective: The objective of the study was to evaluate and compare the effect of conventional and newer antiepileptic drugs (AEDs) on thyroid hormone levels in adult epileptic patients. Methods: A hospital-based, analytical cross-sectional study was conducted among the adult epileptic patients receiving conventional AEDs (Group 2) or newer AEDs (Group 3) for more than 6 months. Serum thyroid hormone levels including free triiodothyronine (fT3), free thyroxine (fT4), and thyroid stimulating hormone (TSH) were analyzed and the hormonal status was compared with healthy control subjects (Group 1). Findings: Sodium valproate and phenytoin were commonly used conventional AEDs; levetiracetam and topiramate were common among the newer drugs. There was a statistically significant decrease in serum fT4 and increase in serum TSH levels (P < 0.0001) in patients on long-term therapy with conventional antiepileptic agents than in the control group. No significant change in thyroid hormone levels (fT3, fT4, and TSH; P = 0.68, 0.37, and 0.90, respectively) was observed with newer antiepileptics-treated patients when compared to control group. One-way analysis of variance followed by post hoc Dunnett's test was performed using SPSS version 17.0 software package. Conclusion: The present study showed that conventional AEDs have significant alteration in the thyroid hormone levels than the newer antiepileptics in adult epileptic patients. PMID:27512707

  1. Geometrical and band-structure effects on phonon-limited hole mobility in rectangular cross-sectional germanium nanowires

    SciTech Connect

    Tanaka, H. Mori, S.; Morioka, N.; Suda, J.; Kimoto, T.

    2014-12-21

    We calculated the phonon-limited hole mobility in rectangular cross-sectional [001], [110], [111], and [112]-oriented germanium nanowires, and the hole transport characteristics were investigated. A tight-binding approximation was used for holes, and phonons were described by a valence force field model. Then, scattering probability of holes by phonons was calculated taking account of hole-phonon interaction atomistically, and the linearized Boltzmann's transport equation was solved to calculate the hole mobility at low longitudinal field. The dependence of the hole mobility on nanowire geometry was analyzed in terms of the valence band structure of germanium nanowires, and it was found that the dependence was qualitatively reproduced by considering an average effective mass and the density of states of holes. The calculation revealed that [110] germanium nanowires with large height along the [001] direction show high hole mobility. Germanium nanowires with this geometry are also expected to exhibit high electron mobility in our previous work, and thus they are promising for complementary metal-oxide-semiconductor (CMOS) applications.

  2. About the Effect of Control on Flutter and Post-Flutter of a Supersonic/Hypersonic Cross-Sectional Wing

    NASA Technical Reports Server (NTRS)

    Silva, Walter A.; Librescu, Liviu; Marzocca, Piergiovanni

    2001-01-01

    The control of the flutter instability and the conversion of the dangerous character of the flutter instability boundary into the undangerous one of a cross-sectional wing in a supersonic/hypersonic flow field is presented. The objective of this paper is twofold: i) to analyze the implications of nonlinear unsteady aerodynamics and physical nonlinearities on the character of the instability boundary in the presence of a control capability, and ii) to outline the effects played in the same respect by some important parameters of the aeroelastic system. As a by-product of this analysis, the implications of the active control on the linearized flutter behavior of the system are captured and emphasized. The bifurcation behavior of the open/closed loop aeroelastic system in the vicinity of the flutter boundary is studied via the use of a new methodology based on the Liapunov First Quantity. The expected outcome of this study is: a) to greatly enhance the scope and reliability of the aeroelastic analysis and design criteria of advanced supersonic/hypersonic flight vehicles and, b) provide a theoretical basis for the analysis of more complex nonlinear aeroelastic systems.

  3. K-edge photoabsorption cross section in metal oxides: Effect of vacancies in TiOx and VOx

    NASA Astrophysics Data System (ADS)

    Kutzler, F. W.; Ellis, D. E.

    1984-06-01

    The x-ray K-edge photoabsorption cross sections for TiO and VO have been calculated, with the use of the self-consistent one-electron local-density theory. Energy levels, charge distribution, and cross sections were obtained from a 27-atom "microcrystal," with a molecular-cluster approach in the discrete-variational method. A detailed comparison is made with experimental spectra for VOx; features of theory and experiment are in good agreement if one assumes a relaxation of the nearest-neighbor oxygen atoms for the O-vacancy cluster. Bound-to-bound transitions are found to contribute significantly to the near-edge structure for the defect crystal.

  4. Activation evaluation and isotopic effects in the (n, p) reaction cross section on A-180 target nuclei

    SciTech Connect

    Avrigeanu, M.; Forrest, R. A.; Roman, F. L.; Avrigeanu, V.

    2006-07-01

    The fast-neutron nuclear data for the stable isotopes of tungsten, tantalum and hafnium, which are important in nuclear technology applications, have been consistently analyzed by means of the nuclear model computer codes TALYS, EMPIRE-II and STAPRE-H. The latter code uses a unique parameter set. The long-lived Hf isomers, which could be produced after a few reactions on W and Ta in the first-wall material of fusion power plants, need special consideration. The analysis, making use of global as well as local parameters within different model assumptions, aims to increase the predictive power of the models, which is of interest to basic as well as applied questions. This work suggests a physical reason for some of the discrepancies between experimental and calculated cross sections for (n, p) and (n, {alpha}) reactions on {sup 181}Ta. Thus, the rather similar Q-values for the (n, p) reaction on the {sup 179}Hf, {sup 181}Ta, and {sup 183}W odd-A target nuclei, also with similar asymmetry-parameter values, support the comparable cross sections which are predicted by all three computer code calculations at variance with the lower measured cross sections of the {sup 181}Ta(n, p) {sup 181}Hf reaction. (authors)

  5. abo-cross: Hydrogen broadening cross-section calculator

    NASA Astrophysics Data System (ADS)

    Barklem, P. S.; Anstee, S. D.; O'Mara, B. J.

    2015-07-01

    Line broadening cross sections for the broadening of spectral lines by collisions with neutral hydrogen atoms have been tabulated by Anstee & O'Mara (1995), Barklem & O'Mara (1997) and Barklem, O'Mara & Ross (1998) for s-p, p-s, p-d, d-p, d-f and f-d transitions. abo-cross, written in Fortran, interpolates in these tabulations to make these data more accessible to the end user. This code can be incorporated into existing spectrum synthesis programs or used it in a stand-alone mode to compute line broadening cross sections for specific transitions.

  6. Intraclass correlation and design effect in BMI, physical activity and diet: a cross-sectional study of 56 countries

    PubMed Central

    Masood, Mohd; Reidpath, Daniel D

    2016-01-01

    Objectives Measuring the intraclass correlation coefficient (ICC) and design effect (DE) may help to modify the public health interventions for body mass index (BMI), physical activity and diet according to geographic targeting of interventions in different countries. The purpose of this study was to quantify the level of clustering and DE in BMI, physical activity and diet in 56 low-income, middle-income and high-income countries. Design Cross-sectional study design. Setting Multicountry national survey data. Methods The World Health Survey (WHS), 2003, data were used to examine clustering in BMI, physical activity in metabolic equivalent of task (MET) and diet in fruits and vegetables intake (FVI) from low-income, middle-income and high-income countries. Multistage sampling in the WHS used geographical clusters as primary sampling units (PSU). These PSUs were used as a clustering or grouping variable in this analysis. Multilevel intercept only regression models were used to calculate the ICC and DE for each country. Results The median ICC (0.039) and median DE (1.82) for BMI were low; however, FVI had a higher median ICC (0.189) and median DE (4.16). For MET, the median ICC was 0.141 and median DE was 4.59. In some countries, however, the ICC and DE for BMI were large. For instance, South Africa had the highest ICC (0.39) and DE (11.9) for BMI, whereas Uruguay had the highest ICC (0.434) for MET and Ethiopia had the highest ICC (0.471) for FVI. Conclusions This study shows that across a wide range of countries, there was low area level clustering for BMI, whereas MET and FVI showed high area level clustering. These results suggested that the country level clustering effect should be considered in developing preventive approaches for BMI, as well as improving physical activity and healthy diets for each country. PMID:26743697

  7. Effects of mouthguards on vertical dimension, muscle activation, and athlete preference: a prospective cross-sectional study.

    PubMed

    Gage, C Colby; Huxel Bliven, Kellie C; Bay, R Curtis; Sturgill, Jeremiah S; Park, Jae Hyun

    2015-01-01

    Mandibular repositioning and subsequent neuromuscular signaling are proposed mechanisms of action for commercial mouthguards marketed for performance enhancement. A prospective cross-sectional study of 24 healthy adult weightlifters with normal occlusal relationships was designed to determine whether 2 self-fit performance mouthguards; a custom-fabricated, bilaterally balanced, dual-laminated mouthguard; and no mouthguard (control) differed in their effects on vertical dimension, muscle activation, and user preference during a 75% maximum power clean lift. Each subject was tested for each of the mouthguard categories: Power Balance POWERUP, Under Armour ArmourBite, custom, and no mouthguard. Interocclusal distance was measured at baseline and with each mouthguard. Mean and peak activity of the anterior temporalis, masseter, sternocleidomastoid, and cervical paraspinal muscles was measured during sitting and during a 75% maximum power clean lift. A mouthguard preference questionnaire was completed. Analyses were conducted to determine whether interocclusal distance differed among mouthguard type and to examine the effect of mouthguard type on mean and peak muscle activation during the clean lift. Interocclusal distance was affected by mouthguard type (P = 0.01). Mean and peak activity of the anterior temporalis and masseter muscles and mean activity of the sternocleidomastoid muscle differed among mouthguards (P < 0.05). Mouthguard type did not influence muscle activation of the cervical paraspinal muscle group. Overall, the Power Balance mouthguard produced more muscle activity. Participants preferred custom mouthguards nearly 2:1 over self-fit performance mouthguards (P = 0.05). Participants perceived that they were stronger and were less encumbered when using a custom mouthguard during submaximum power clean lifts. PMID:26545275

  8. The effects of insomnia and internet addiction on depression in Hong Kong Chinese adolescents: an exploratory cross-sectional analysis.

    PubMed

    Cheung, Lee M; Wong, Wing S

    2011-06-01

    The negative association of insomnia and internet addiction with mental health is widely documented in the literature, yet little is known about their inter-relationships. The primary aim of this study was to examine the inter-relationships between insomnia, internet addiction and depression. A total of 719 Chinese adolescents in Hong Kong participated in this school-based cross-sectional study. Participants completed the Chinese version of the Pittsburgh Sleep Quality Index (PSQI), the Chinese Internet Addiction Scale (CIAS), the 12-item version of General Health Questionnaire (GHQ-12) and questions assessing internet use pattern and sociodemographic characteristics. The classification of internet addiction and insomnia was based on the CIAS cutoff global score >63 and PSQI cutoff global score >5, respectively. Multiple regression analyses tested the effects of insomnia and internet addiction on depression. Among students with internet addiction (17.2%), 51.7% were also identified as insomniacs. Internet addicts scored significantly poorer on all PSQI components, except sleep duration, than their non-addicted counterparts. After adjustment for gender and internet use time, both internet addiction (β=0.05; Sobel test Z=6.50, P<0.001) and insomnia (β=0.59; Sobel test Z=4.49, P<0.001) demonstrated a significant association with depression. Overall, there is high comorbidity between internet addiction and insomnia. Both insomnia and internet addiction emerged as significant explanatory factors, but they exerted differential effects on depression. Future research should be directed at determining the causal relationship between internet addiction and insomnia, and its underlying mechanism with depression. PMID:20819144

  9. Revised cross section for RHIC dipole magnets

    SciTech Connect

    Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J.; Willen, E.

    1991-01-01

    Using the experience gained in designing and building Relativistic Heavy Ion Collider (RHIC) dipole prototype magnets an improved cross section has been developed. Significant features of this design include the use of only three wedges for field shaping and wedge cross sections which are sectors of an annulus. To aid in the understanding of the actual magnets, one has been sectioned, and detailed mechanical and photographic measurements made of the wire positions. The comparison of these measurements with the magnetic field measurements will is presented. 2 refs, 3 figs., 2 tabs.

  10. Actinide cross section program at ORELA

    SciTech Connect

    Dabbs, J.W.T.

    1980-01-01

    The actinide cross section program at ORELA, the Oak Ridge Electron Linear Accelerator, is aimed at obtaining accurate neutron cross sections (primarily fission, capture, and total) for actinide nuclides which occur in fission reactors. Such cross sections, measured as a function of neutron energy over as wide a range of energies as feasible, comprise a data base that permits calculated predictions of the formation and removal of these nuclides in reactors. The present program is funded by the Division of Basic Energy Sciences of DOE, and has components in several divisions at ORNL. For intensively ..cap alpha..-active nuclides, many of the existing fission cross section data have been provided by underground explosions. New measurement techniques, developed at ORELA, now permit linac measurements on fissionable nuclides with alpha half-lives as short as 28 years. Capture and capture-plus-fission measurements utilize scintillation detectors (of capture ..gamma.. rays and fission neutrons) in which pulse shape discrimination plays an important role. Total cross sections can be measured at ORELA on samples of only a few milligrams. A simultaneous program of chemical and isotopic analyses of samples irradiated in EBR-II is in progress to provide benchmarks for the existing differential measurements. These analyses are being studied with updated versions of ORIGEN and with sensitivity determinations. Calculations of the sensitivity to cross section changes of various aspects of the nuclear fuel cycle are also being made. Even in this relatively mature field, many cross sections still require improvements to provide an adequate data base. Examples of recent techniques and measurements are presented. 12 figures, 3 tables.

  11. Comparison of the Effects of Hollowing and Bracing Exercises on Cross-sectional Areas of Abdominal Muscles in Middle-aged Women

    PubMed Central

    Koh, Hyung-Woo; Cho, Sung-Hyoun; Kim, Cheol-Yong

    2014-01-01

    [Purpose] The purpose of this study was to examine the effects of hollowing and bracing exercises on cross-sectional areas of abdominal muscles. [Subjects] Thirty healthy female adults participated in this study. The exclusion criteria were orthopedic or neurologic diseases. [Methods] The subjects of this study were assigned randomly to one of two groups, each with 15 people. Each group performed a 60-minute exercise program, one performed a bracing exercise, and the other performed a hollowing exercise, with both groups performing the exercise three times a week for six weeks. [Results] The changes in cross-sectional areas after the bracing exercise showed statistically significant differences in the left rectus abdominis and both internal and external obliques. The changes in cross-sectional areas after the hollowing exercise showed statistically significant differences in the left and right transversus abdominis and left rectus abdominis. [Conclusion] Performing bracing exercises rather than hollowing exercises is more effective for activating the abdominal muscles. PMID:24648652

  12. Investigation of the pairing effect using newly evaluated empirical studies for 14-15 MeV neutron reaction cross sections

    SciTech Connect

    Tel, E.; Tanir, G.; Aydin, A.

    2007-03-15

    The asymmetry term effects for the cross sections of (n, charged particle) and (n,2n) reactions at 14-15 MeV neutron incident energy have been investigated. The effects of pairing and odd-even nucleon numbers in new data and in the formula of Tel et al. [J. Phys. G. 29, 2169 (2003)] are discussed. We have determined three different parameters groups by the classification of nuclei into even-even, even-odd, and odd-even (n,d) reactions. In addition, since there are not enough experimental data available, we have considered two different parameters groups by the classification of nuclei into odd-A and even-A (n,t) reaction cross sections. The empirical formulas with two parameters for the evaluation of the (n,d) and (n,t) reactions cross sections are discussed in the present study.

  13. Geophysical Fluid Flow Cell (GFFC) Cross Section

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This drawing shows a cross-section view of the test cell at the heart of the Geophysical Fluid Flow Cell (GFFC) that flew on two Spacelab missions. The middle and lower drawings depict the volume of the silicone oil layer that served as the atmosphere as the steel ball rotated and an electrostatic field pulled the oil inward to mimic gravity's effects during the experiments. The GFFC thus produced flow patterns that simulated conditions inside the atmospheres of Jupiter and the Sun and other stars. The principal investigator was John Hart of the University of Colorado at Boulder. It was managed by NASA's Marshall Space Flight Center (MSFC). An Acrobat PDF copy of this drawing is available at http://microgravity.nasa.gov/gallery. (Credit: NASA/Marshall Space Flight Center)

  14. Reduction Methods for Total Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Gomes, P. R. S.; Mendes Junior, D. R.; Canto, L. F.; Lubian, J.; de Faria, P. N.

    2016-03-01

    The most frequently used methods to reduce fusion and total reaction excitation functions were investigated in a very recent paper Canto et al. (Phys Rev C 92:014626, 2015). These methods are widely used to eliminate the influence of masses and charges in comparisons of cross sections for weakly bound and tightly bound systems. This study reached two main conclusions. The first is that the fusion function method is the most successful procedure to reduce fusion cross sections. Applying this method to theoretical cross sections of single channel calculations, one obtains a system independent curve (the fusion function), that can be used as a benchmark to fusion data. The second conclusion was that none of the reduction methods available in the literature is able to provide a universal curve for total reaction cross sections. The reduced single channel cross sections keep a strong dependence of the atomic and mass numbers of the collision partners, except for systems in the same mass range. In the present work we pursue this problem further, applying the reduction methods to systems within a limited mass range. We show that, under these circumstances, the reduction of reaction data may be very useful.

  15. Undergraduate Measurements of Neutron Cross Sections

    NASA Astrophysics Data System (ADS)

    Hicks, S. F.; Vanhoy, J. R.; French, A. J.; Santonil, Z. C.; Crider, B. P.; Peters, E. E.; McEllistrem, M. T.; Prados-Estévez, F. M.; Ross, T. J.; Yates, S. W.

    Undergraduate students at the University of Dallas have investigated basic properties of nuclei through γ-ray and neutron spectroscopy following neutron scattering. The former has been used primarily for nuclear structure investigations, while the latter has been used to measure neutron scattering cross sections important for fission reactor applications. A series of (n,n') and (n,n'γ) measurements have been made on 54Fe and 56Fe to determine neutron cross sections for scattering to excited levels in these nuclei. The former provides the cross sections directly and the latter are used to deduce inelastic neutron scattering cross sections by measuring the γ-ray production cross sections to states not easily resolved in neutron spectroscopy. All measurements have been completed at the University of Kentucky Accelerator Laboratory using a 7-MV Model CN Van de Graaff accelerator, along with the neutron production and neutron and γ-ray detection systems located there. Students participate in accelerator operation, experimental setup, data acquisition, and data analyses. An overview of the research program and student contributions is presented.

  16. Effect of education and health locus of control on safe use of pesticides: a cross sectional random study

    PubMed Central

    2012-01-01

    Background In Egypt, many pesticides are used to control pests in agricultural farms. Our study aimed to investigate knowledge and behaviors of farmers related to pesticide use and their relation to educational level and health locus of control. Health locus of control is the degree to which individuals believe that their health is controlled by internal or external factors. Methods A cross-sectional randomized approach was used to collect data from 335 farmers in Mahmoudiya region, Egypt using an interview questionnaire. Results were analyzed using Pearson Chi-square test, Fisher's exact test, Student t-test and ANOVA. Results The average age of farmers was 34 years and 61% of them didn't receive school education. School education was related to higher levels of knowledge and behaviors. Farmers who received school education had more knowledge about the negative effects of pesticides on health and routes of contamination with pesticides. They also had higher scores on reading labels of pesticides containers and taking precautions after coming in contact with pesticides. Regarding health locus of control, higher internal beliefs were significantly related to higher knowledge and behaviors scores, while there was no significant relation between chance and powerful others beliefs with knowledge or behaviors. Conclusion In the present study, higher level of education and lower level of internal beliefs were related to better knowledge and safer use of pesticides among Egyptian farmers. We recommend that strategies for raising internal beliefs must be included in health education programs that aim to ameliorate pesticides use among farmers. PMID:22364384

  17. QSO ABSORPTION SYSTEMS DETECTED IN Ne VIII: HIGH-METALLICITY CLOUDS WITH A LARGE EFFECTIVE CROSS SECTION

    SciTech Connect

    Meiring, J. D.; Tripp, T. M.; Werk, J. K.; Prochaska, J. X.; Howk, J. C.; Jenkins, E. B.; Lehner, N.; Sembach, K. R.

    2013-04-10

    Using high-resolution, high signal-to-noise ultraviolet spectra of the z{sub em} = 0.9754 quasar PG1148+549 obtained with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope, we study the physical conditions and abundances of Ne VIII+O VI absorption line systems at z{sub abs} = 0.68381, 0.70152, 0.72478. In addition to Ne VIII and O VI, absorption lines from multiple ionization stages of oxygen (O II, O III, O IV) are detected and are well aligned with the more highly ionized species. We show that these absorbers are multiphase systems including hot gas (T Almost-Equal-To 10{sup 5.7} K) that produces Ne VIII and O VI, and the gas metallicity of the cool phase ranges from Z = 0.3 Z{sub Sun} to supersolar. The cool ( Almost-Equal-To 10{sup 4} K) phases have densities n{sub H} Almost-Equal-To 10{sup -4} cm{sup -3} and small sizes (<4 kpc); these cool clouds are likely to expand and dissipate, and the Ne VIII may be within a transition layer between the cool gas and a surrounding, much hotter medium. The Ne VIII redshift density, dN/dz{approx}7{sup +7}{sub -3}, requires a large number of these clouds for every L > 0.1 L* galaxy and a large effective absorption cross section ({approx}> 100 kpc), and indeed, we find a star-forming {approx}L {sup *} galaxy at the redshift of the z{sub abs} = 0.72478 system, at an impact parameter of 217 kpc. Multiphase absorbers like these Ne VIII systems are likely to be an important reservoir of baryons and metals in the circumgalactic media of galaxies.

  18. Stress and its effects on medical students: a cross-sectional study at a college of medicine in Saudi Arabia.

    PubMed

    Abdulghani, Hamza M; AlKanhal, Abdulaziz A; Mahmoud, Ebrahim S; Ponnamperuma, Gominda G; Alfaris, Eiad A

    2011-10-01

    Medical education is perceived as being stressful, and a high level of stress may have a negative effect on cognitive functioning and learning of students in a medical school. This cross-sectional study was conducted to determine the prevalence of stress among medical students and to observe an association between the levels of stress and their academic performance, including the sources of their stress. All the medical students from year one to year five levels from the College of Medicine, King Saud University, were enrolled in the study. The study was conducted using Kessler10 psychological distress (K10) inventory, which measures the level of stress according to none, mild, moderate, and severe categories. The prevalence of stress was measured and compared with the five study variables, such as gender, academic year, academic grades, regularity to course attendance, and perceived physical problems. The response rate among the study subjects was 87% (n=892). The total prevalence of stress was 63%, and the prevalence of severe stress was 25%. The prevalence of stress was higher (p<0.5) among females (75.7%) than among males (57%) (odds ratio=2.3, chi2=27.2, p<0.0001). The stress significantly decreased as the year of study increased, except for the final year. The study variables, including being female (p<0.0001), year of study (p<0.001), and presence of perceived physical problems (p<0.0001), were found as independent significant risk factors for the outcome variables of stress. Students' grade point average (academic score) or regularity to attend classes was not significantly associated with the stress level. The prevalence of stress was higher during the initial three years of study and among the female students. Physical problems are associated with high stress levels. Preventive mental health services, therefore, could be made an integral part of routine clinical services for medical students, especially in the initial academic years, to prevent such

  19. Evaluation of Community-Level Effects of Communities That Care on Adolescent Drug Use and Delinquency Using a Repeated Cross-Sectional Design.

    PubMed

    Rhew, Isaac C; Hawkins, J David; Murray, David M; Fagan, Abigail A; Oesterle, Sabrina; Abbott, Robert D; Catalano, Richard F

    2016-02-01

    The Communities That Care (CTC) prevention system has shown effects on reducing incidence and prevalence of problem behaviors among a panel of youth followed from 5th through 12th grade. The present report examines whether similar intervention effects could be observed using a repeated cross-sectional design in the same study. Data were from a community-randomized trial of 24 US towns. Cross-sectional samples of sixth, eighth, and tenth graders were surveyed at four waves. Two-stage ANCOVA analyses estimated differences between CTC and control communities in community-level prevalence of problem behaviors for each grade, adjusting for baseline prevalence. No statistically significant reductions in prevalence of problem behaviors were observed at any grade in CTC compared to control communities. Secondary analyses examined intervention effects within a “pseudo cohort” where cross-sectional data were used from sixth graders at baseline and tenth graders 4 years later. When examining effects within the pseudo cohort, CTC compared to control communities showed a significantly slower increase from sixth to tenth grade in lifetime smokeless tobacco use but not for other outcomes. Exploratory analyses showed significantly slower increases in lifetime problem behaviors within the pseudo cohort for CTC communities with high, but not low, prevention program saturation compared to control communities. Although CTC demonstrated effects in a longitudinal panel from the same community-randomized trial, we did not find similar effects on problem behaviors using a repeated cross-sectional design. These differences may be due to a reduced ability to detect effects because of potential cohort effects, accretion of those who were not exposed, and attrition of those who were exposed to CTC programming in the repeated cross-sectional sample. PMID:26462492

  20. Top differential cross section measurements (Tevatron)

    SciTech Connect

    Jung, Andreas W.

    2012-01-01

    Differential cross sections in the top quark sector measured at the Fermilab Tevatron collider are presented. CDF used 2.7 fb{sup -1} of data and measured the differential cross section as a function of the invariant mass of the t{bar t} system. The measurement shows good agreement with the standard model and furthermore is used to derive limits on the ratio {kappa}/M{sub Pl} for gravitons which decay to top quarks in the Randall-Sundrum model. D0 used 1.0 fb{sup -1} of data to measure the differential cross section as a function of the transverse momentum of the top-quark. The measurement shows a good agreement to the next-to-leading order perturbative QCD prediction and various other standard model predictions.

  1. The cross section for double Compton scattering

    NASA Technical Reports Server (NTRS)

    Gould, R. J.

    1984-01-01

    Employing elementary methods in nonrelativistic quantum electrodynamics, the cross section for gamma sub 0 + e yields e + gamma + gamma is computed for arbitrary energy in the spectrum of the outgoing photons. The final result is given, differential in the energy of one of these photons, for the case where the incident photon is unpolarized and has energy E sub 0 much less than mc-squared, a polarization sum and angular integration being performed for the final-state photons. The cross section has a simple algebraic form resulting from contributions from the sum of squared direct and exchange amplitudes; interference terms from these amplitudes do not contribute to the angular-integrated cross section.

  2. Algorithmic analysis of quantum radar cross sections

    NASA Astrophysics Data System (ADS)

    Lanzagorta, Marco; Venegas-Andraca, Salvador

    2015-05-01

    Sidelobe structures on classical radar cross section graphs are a consequence of discontinuities in the surface currents. In contrast, quantum radar theory states that sidelobe structures on quantum radar cross section graphs are due to quantum interference. Moreover, it is conjectured that quantum sidelobe structures may be used to detect targets oriented off the specular direction. Because of the high data bandwidth expected from quantum radar, it may be necessary to use sophisticated quantum signal analysis algorithms to determine the presence of stealth targets through the sidelobe structures. In this paper we introduce three potential quantum algorithmic techniques to compute classical and quantum radar cross sections. It is our purpose to develop a computer science-oriented tool for further physical analysis of quantum radar models as well as applications of quantum radar technology in various fields.

  3. Systematic study of three-nucleon force effects in the cross section of the deuteron-proton breakup at 130 MeV

    SciTech Connect

    St. Kistryn; E. Stephan; A. Biegun; K. Bodek; A. Deltuva; E. Epelbaum; K. Ermisch; W. Gloeckle; J. Golak; N. Kalantar-Nayestanaki; H. Kamada; M. Kis; B. Klos; A. Kozela; J. Kuros-Zolnierczuk; M. Mahjour-Shafiei; U.-G. Meissner; A. Micherdzinska; A. Nogga; P. U. Sauer; R. Skibinski; R. Sworst; H. Witala; J. Zejma; W. Zipper

    2005-08-11

    High precision cross-section data of the deuteron-proton breakup reaction at 130 MeV are presented for 72 kinematically complete configurations. The data cover a large region of the available phase space, divided into a systematic grid of kinematical variables. They are compared with theoretical predictions, in which the full dynamics of the three-nucleon (3N) system is obtained in three different ways: realistic nucleon-nucleon (NN) potentials are combined with model 3N forces (3NF's) or with an effective 3NF resulting from explicit treatment of the Delta-isobar excitation. Alternatively, the chiral perturbation theory approach is used at the next-to-next-to-leading order with all relevant NN and 3N contributions taken into account. The generated dynamics is then applied to calculate cross-section values by rigorous solution of the 3N Faddeev equations. The comparison of the calculated cross sections with the experimental data shows a clear preference for the predictions in which the 3NF's are included. The majority of the experimental data points is well reproduced by the theoretical predictions. The remaining discrepancies are investigated by inspecting cross sections integrated over certain kinematical variables. The procedure of global comparisons leads to establishing regularities in disagreements between the experimental data and the theoretically predicted values of the cross sections. They indicate deficiencies still present in the assumed models of the 3N system dynamics.

  4. The effects of health worker motivation and job satisfaction on turnover intention in Ghana: a cross-sectional study

    PubMed Central

    2014-01-01

    Background Motivation and job satisfaction have been identified as key factors for health worker retention and turnover in low- and middle-income countries. District health managers in decentralized health systems usually have a broadened ‘decision space’ that enables them to positively influence health worker motivation and job satisfaction, which in turn impacts on retention and performance at district-level. The study explored the effects of motivation and job satisfaction on turnover intention and how motivation and satisfaction can be improved by district health managers in order to increase retention of health workers. Methods We conducted a cross-sectional survey in three districts of the Eastern Region in Ghana and interviewed 256 health workers from several staff categories (doctors, nursing professionals, allied health workers and pharmacists) on their intentions to leave their current health facilities as well as their perceptions on various aspects of motivation and job satisfaction. The effects of motivation and job satisfaction on turnover intention were explored through logistic regression analysis. Results Overall, 69% of the respondents reported to have turnover intentions. Motivation (OR = 0.74, 95% CI: 0.60 to 0.92) and job satisfaction (OR = 0.74, 95% CI: 0.57 to 0.96) were significantly associated with turnover intention and higher levels of both reduced the risk of health workers having this intention. The dimensions of motivation and job satisfaction significantly associated with turnover intention included career development (OR = 0.56, 95% CI: 0.36 to 0.86), workload (OR = 0.58, 95% CI: 0.34 to 0.99), management (OR = 0.51. 95% CI: 0.30 to 0.84), organizational commitment (OR = 0.36, 95% CI: 0.19 to 0.66), and burnout (OR = 0.59, 95% CI: 0.39 to 0.91). Conclusions Our findings indicate that effective human resource management practices at district level influence health worker motivation and job satisfaction

  5. Temperature dependence of the HNO3 UV absorption cross sections

    NASA Technical Reports Server (NTRS)

    Burkholder, James B.; Talukdar, Ranajit K.; Ravishankara, A. R.; Solomon, Susan

    1993-01-01

    The temperature dependence of the HNO3 absorption cross sections between 240 and 360 K over the wavelength range 195 to 350 nm has been measured using a diode array spectrometer. Absorption cross sections were determined using both (1) absolute pressure measurements at 298 K and (2) a dual absorption cell arrangement in which the absorption spectrum at various temperatures is measured relative to the room temperature absorption spectrum. The HNO3 absorption spectrum showed a temperature dependence which is weak at short wavelengths but stronger at longer wavelengths which are important for photolysis in the lower stratosphere. The 298 K absorption cross sections were found to be larger than the values currently recommended for atmospheric modeling (DeMore et al., 1992). Our absorption cross section data are critically compared with the previous measurements of both room temperature and temperature-dependent absorption cross sections. Temperature-dependent absorption cross sections of HNO3 are recommended for use in atmospheric modeling. These temperature dependent HNO3 absorption cross sections were used in a two-dimensional dynamical-photochemical model to demonstrate the effects of the revised absorption cross sections on loss rate of HNO3 and the abundance of NO2 in the stratosphere.

  6. Effect of Coulomb breakup on the elastic cross section of the 8B proton-halo projectile on a heavy, 208Pb target

    NASA Astrophysics Data System (ADS)

    Rangel, J.; Lubian, J.; Canto, L. F.; Gomes, P. R. S.

    2016-05-01

    We investigate the role of the breakup channel in the elastic and breakup cross sections, in collisions of proton-halo nuclei. For this purpose, we perform continuum discretized couple channel (CDCC) calculations for the 8B+208Pb system and evaluate polarization potentials. One-channel calculations including the polarization potential are shown to reproduce very well the elastic cross sections obtained by CDCC calculations. We also study the individual contributions of the Coulomb and the nuclear couplings to the cross sections. To complement our study, we compare the effects of the breakup channel in proton-halo and neutron-halo nuclei, performing calculations treating 8B as a 7B+n core-nucleon system, with an artificially low breakup threshold. When only the nuclear breakup is considered, this approach can reasonably describe the elastic scattering.

  7. Infrared absorption cross sections of alternative CFCs

    NASA Technical Reports Server (NTRS)

    Clerbaux, Cathy; Colin, Reginald; Simon, Paul C.

    1994-01-01

    Absorption cross sections have obtained in the infrared atmospheric window, between 600 and 1500 cm(exp -1), for 10 alternative hydrohalocarbons: HCFC-22, HCFC-123, HCFC-124, HCFC-141b, HCFC-142b, HCFC-225ca, HCFC-225cb, HFC-125, HFC-134a, and HFC-152a. The measurements were made at three temperatures (287K, 270K and 253K) with a Fourier transform spectrometer operating at 0.03 cm(exp -1) apodized resolution. Integrated cross sections are also derived for use in radiative models to calculate the global warming potentials.

  8. Covariance Evaluation Methodology for Neutron Cross Sections

    SciTech Connect

    Herman,M.; Arcilla, R.; Mattoon, C.M.; Mughabghab, S.F.; Oblozinsky, P.; Pigni, M.; Pritychenko, b.; Songzoni, A.A.

    2008-09-01

    We present the NNDC-BNL methodology for estimating neutron cross section covariances in thermal, resolved resonance, unresolved resonance and fast neutron regions. The three key elements of the methodology are Atlas of Neutron Resonances, nuclear reaction code EMPIRE, and the Bayesian code implementing Kalman filter concept. The covariance data processing, visualization and distribution capabilities are integral components of the NNDC methodology. We illustrate its application on examples including relatively detailed evaluation of covariances for two individual nuclei and massive production of simple covariance estimates for 307 materials. Certain peculiarities regarding evaluation of covariances for resolved resonances and the consistency between resonance parameter uncertainties and thermal cross section uncertainties are also discussed.

  9. New Parameterization of Neutron Absorption Cross Sections

    NASA Technical Reports Server (NTRS)

    Tripathi, Ram K.; Wilson, John W.; Cucinotta, Francis A.

    1997-01-01

    Recent parameterization of absorption cross sections for any system of charged ion collisions, including proton-nucleus collisions, is extended for neutron-nucleus collisions valid from approx. 1 MeV to a few GeV, thus providing a comprehensive picture of absorption cross sections for any system of collision pairs (charged or uncharged). The parameters are associated with the physics of the problem. At lower energies, optical potential at the surface is important, and the Pauli operator plays an increasingly important role at intermediate energies. The agreement between the calculated and experimental data is better than earlier published results.

  10. Precise neutron inelastic cross section measurements

    SciTech Connect

    Negret, Alexandru

    2012-11-20

    The design of a new generation of nuclear reactors requires the development of a very precise neutron cross section database. Ongoing experiments performed at dedicated facilities aim to the measurement of such cross sections with an unprecedented uncertainty of the order of 5% or even smaller. We give an overview of such a facility: the Gamma Array for Inelastic Neutron Scattering (GAINS) installed at the GELINA neutron source of IRMM, Belgium. Some of the most challenging difficulties of the experimental approach are emphasized and recent results are shown.

  11. Cross sections of neutron-induced reactions

    SciTech Connect

    Mukhopadhyay, Tapan; Lahiri, Joydev; Basu, D. N.

    2010-10-15

    We study the properties of the neutron-nucleus total and reaction cross sections for several nuclei. We have applied an analytical model, the nuclear Ramsauer model, justified it from the nuclear reaction theory approach, and extracted the values of 12 parameters used in the model. The given parametrization has an advantage as phenomenological optical model potentials are limited up to 150-200 MeV. The present model provides good estimates of the total cross sections for several nuclei particularly at high energies.

  12. Neutron capture cross section of 136 Xe

    NASA Astrophysics Data System (ADS)

    Daugherty, Sean; Albert, Joshua; Johnson, Tessa; O'Conner, Thomasina; Kaufman, Lisa

    2015-04-01

    136 Xe is an important 0 νββ candidate, studied in experiments such as EXO-200 and, in the future, nEXO. These experiments require a precise study of neutron capture for their background models. The neutron capture cross section of 136 Xe has been measured at the Detector for Advanced Capture Experiments (DANCE) at the Los Alamos Neutron Science Center. A neutron beam ranging from thermal energy to 100 keV was incident on a gas cell filled with isotopically pure 136 Xe . We will discuss the measurement of partial neutron capture cross sections at thermal and first neutron resonance energies along with corresponding capture gamma cascades.

  13. Neutron Capture Cross Section of 239Pu

    NASA Astrophysics Data System (ADS)

    Mosby, S.; Arnold, C.; Bredeweg, T. A.; Couture, A.; Jandel, M.; O'Donnell, J. M.; Rusev, G.; Ullmann, J. L.; Chyzh, A.; Henderson, R.; Kwan, E.; Wu, C. Y.

    2014-09-01

    The 239Pu(n,γ) cross section has been measured over the energy range 10 eV - 10 keV using the Detector for Advanced Neutron Capture Experiments (DANCE) as part of a campaign to produce precision (n,γ) measurements on 239Pu in the keV region. Fission coincidences were measured with a PPAC and used to characterize the prompt fission γ-ray spectrum in this region. The resulting spectra will be used to better characterize the fission component of another experiment with a thicker target to extend the (n,γ) cross section measurement well into the keV region.

  14. Optical Model and Cross Section Uncertainties

    SciTech Connect

    Herman,M.W.; Pigni, M.T.; Dietrich, F.S.; Oblozinsky, P.

    2009-10-05

    Distinct minima and maxima in the neutron total cross section uncertainties were observed in model calculations using spherical optical potential. We found this oscillating structure to be a general feature of quantum mechanical wave scattering. Specifically, we analyzed neutron interaction with 56Fe from 1 keV up to 65 MeV, and investigated physical origin of the minima.We discuss their potential importance for practical applications as well as the implications for the uncertainties in total and absorption cross sections.

  15. Effect of a vortex in the triply differential cross section for electron-impact K -shell ionization of carbon

    NASA Astrophysics Data System (ADS)

    Ward, S. J.; Macek, J. H.

    2014-12-01

    Vortices are an inherent property of the velocity fields of complex, time-dependent, Schrödinger wave functions ψ occurring where both the real and the imaginary parts of ψ vanish. They have been known since the early work of Dirac on magnetic monopoles and have frequently been studied theoretically. The possibility of observing them by exploiting an "imaging theorem" that relates atomic wave functions to measured electron momentum distributions has recently been proposed. Using the Coulomb-Born approximation, we examine ionization of a K -shell electron of a model carbon atom by fast electron impact. For an incident electron energy of 1801.2 eV and a scattering angle of 4∘, we find a vortex in the velocity field associated with a zero in the ionization T -matrix element and hence in the triply differential cross section, and we obtain a segment of the vortex line. Angular momentum transfer is essential to produce the vortex in the velocity field and the corresponding zero in the ionization T -matrix element and in the triply differential cross section.

  16. On the effects of improved cross-section representation in one-dimensional flow routing models applied to ephemeral rivers

    NASA Astrophysics Data System (ADS)

    Hutton, Christopher J.; Brazier, Richard E.; Nicholas, Andrew P.; Nearing, Mark

    2012-04-01

    Flash floods are an important component of the semiarid hydrological cycle, and provide the potential for groundwater recharge as well as posing a dangerous natural hazard. A number of catchment models have been applied to flash flood prediction; however, in general they perform poorly. This study has investigated whether the incorporation of light detection and ranging (lidar) derived data into the structure of a 1-D flow routing model can improve the prediction of flash floods in ephemeral channels. Two versions of this model, one based on an existing trapezoidal representation of cross-section morphology (K-Tr), and one that uses lidar data (K-Li) were applied to 5 discrete runoff events measured at two locations on the main channel of The Walnut Gulch Experimental Watershed, United States. In general, K-Li showed improved performance in comparison to K-Tr, both when each model was calibrated to individual events and during an evaluation phase when the models (and parameter sets) were applied across events. Sensitivity analysis identified that the K-Li model also had more consistency in behavioral parameter sets across runoff events. In contrast, parameter interaction within K-Tr resulted in poorly constrained behavioral parameter sets across the multidimensional parameter space. These results, revealed with a modeling focus on the structure of a particular element of a distributed catchment model, suggest that lidar derived cross-section morphology can lead to improved, and more robust flash flood prediction.

  17. Nucleon-nucleon cross sections in nuclear matter

    SciTech Connect

    Schulze, H.; Schnell, A.; Roepke, G.; Lombardo, U.

    1997-06-01

    We provide a microscopic calculation of neutron-proton and neutron-neutron cross sections in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Paris potential. We investigate separately the medium effects on the effective mass and on the scattering amplitude. We determine average cross sections suitable for application in the dynamical simulation of heavy ion collisions, including a parametrization of their energy and density dependence. {copyright} {ital 1997} {ital The American Physical Society}

  18. Cross-sectional schooling-health associations misrepresented causal schooling effects on adult health and health-related behaviors: evidence from the Chinese Adults Twins Survey.

    PubMed

    Behrman, Jere R; Xiong, Yanyan; Zhang, Junsen

    2015-02-01

    Adult health outcomes and health behaviors are often associated with schooling. However, such associations do not necessarily imply that schooling has causal effects on health with the signs or magnitudes found in the cross-sectional associations. Schooling may be proxying for unobserved factors related to genetics and family background that directly affect both health and schooling. Recently several studies have used within-monozygotic (MZ) twins methods to control for unobserved factors shared by identical twins. Within-MZ estimates for developed countries are generally smaller than suggested by cross-sectional associations, consistent with positive correlations between unobserved factors that determine schooling and those that determine health. This study contributes new estimates of cross-sectional associations and within-MZ causal effects using the Chinese Adults Twins Survey, the first study of its type for developing countries. The cross-sectional estimates suggest that schooling is significantly associated with adult health-related behaviors (smoking, drinking, exercising) but not with own or spouse health outcomes (general health, mental health, overweight, chronic diseases). However, within-MZ-twins estimators change the estimates for approximately half of these health indicators, in one case declining in absolute magnitudes and becoming insignificant and in the other cases increasing in absolute magnitudes. Within-MZ estimates indicate significant pro-health effects for at least one of the indicators for own health (better mental health), own health-related behaviors (less smoking) and spouse health (less overweight). PMID:25464872

  19. Cross sections relevant to gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Dyer, P.; Bodansky, D.; Maxson, D. R.

    1978-01-01

    Gamma-ray production cross sections were measured for protons and alpha particles incident on targets consisting of nuclei of high cosmic abundance: C-12, N-14, O-16, Ne-20, Mg-24, Si-28 and Fe-56. Solid or gaseous targets were bombarded by monoenergetic beams of protons and alpha particles, and gamma rays were detected by two Ge(Li) detectors. The proton energy for each target was varied from threshold to about 24 MeV (lab); for alphas the range was from threshold to about 27 MeV. For most transitions, it was possible to measure the total cross section by placing the detectors at 30.5 deg and 109.9 deg where the fourth-order Legendre polynomial is zero. For the case of the 16O (E sub gamma = 6.13 MeV, multipolarity E3) cross sections, yields were measured at four angles. Absolute cross sections were obtained by integrating the beam current and by measuring target thicknesses and detector efficiencies. The Ge(Li) detector resolution was a few keV (although the peak widths were greater, due to Doppler broadening).

  20. Photoelectric absorption cross sections with variable abundances

    NASA Technical Reports Server (NTRS)

    Balucinska-Church, Monika; Mccammon, Dan

    1992-01-01

    Polynomial fit coefficients have been obtained for the energy dependences of the photoelectric absorption cross sections of 17 astrophysically important elements. These results allow the calculation of X-ray absorption in the energy range 0.03-10 keV in material with noncosmic abundances.

  1. Testing (Validating?) Cross Sections with ICSBEP Benchmarks

    SciTech Connect

    Kahler, Albert C. III

    2012-06-28

    We discuss how to use critical benchmarks from the International Handbook of Evaluated Criticality Safety Benchmark Experiments to determine the applicability of specific cross sections to the end-user's problem of interest. Particular attention is paid to making sure the selected suite of benchmarks includes the user's range of applicability (ROA).

  2. Cross-sectional structural parameters from densitometry

    NASA Technical Reports Server (NTRS)

    Cleek, Tammy M.; Whalen, Robert T.

    2002-01-01

    Bone densitometry has previously been used to obtain cross-sectional properties of bone from a single X-ray projection across the bone width. Using three unique projections, we have extended the method to obtain the principal area moments of inertia and orientations of the principal axes at each scan cross-section along the length of the scan. Various aluminum phantoms were used to examine scanner characteristics to develop the highest accuracy possible for in vitro non-invasive analysis of cross-sectional properties. Factors considered included X-ray photon energy, initial scan orientation, the angle spanned by the three scans (included angle), and I(min)/I(max) ratios. Principal moments of inertia were accurate to within +/-3.1% and principal angles were within +/-1 degrees of the expected value for phantoms scanned with included angles of 60 degrees and 90 degrees at the higher X-ray photon energy (140 kVp). Low standard deviations in the error (0.68-1.84%) also indicate high precision of calculated measurements with these included angles. Accuracy and precision decreased slightly when the included angle was reduced to 30 degrees. The method was then successfully applied to a pair of excised cadaveric tibiae. The accuracy and insensitivity of the algorithms to cross-sectional shape and changing isotropy (I(min)/I(max)) values when various included angles are used make this technique viable for future in vivo studies.

  3. Neutron Capture Cross Sections for Radioactive Nuclei

    NASA Astrophysics Data System (ADS)

    Tonchev, Anton; Bedrossian, Peter; Escher, Jutta; Scielzo, Nicholas

    2015-10-01

    Accurate neutron-capture cross sections for radioactive nuclei near or far away from the line of beta stability are crucial for understanding the nucleosynthesis of heavy elements. However, neutron-capture cross sections for short-lived radionuclides are difficult to measure due to the fact that the measurements require both highly radioactive samples and intense neutron sources. Essential ingredients for describing the γ decays following neutron capture are the γ-ray strength function and level densities. We will compare different indirect approaches for obtaining observables that can constrain Hauser-Feshbach statistical model calculations of capture cross sections. Specifically, we will consider photon scattering, transfer reactions, and beta-delayed neutron emission. Challenges that exist on the path to obtaining neutron-capture cross sections for reactions on isotopes far from stability will be discussed. This work was performed under the auspices of US DOE by LLNL under contract DE-AC52-07NA27344. Funding was provided via the LDRD-ERD-069 project.

  4. Electron impact excitation cross sections for carbon

    NASA Astrophysics Data System (ADS)

    Ganas, P. S.

    1981-04-01

    A realistic analytic atomic independent particle model is used to generate wave functions for the valence and excited states of carbon. Using these wave functions in conjunction with the Born approximation and the Russell-Saunders LS-coupling scheme, we calculate generalized oscillator strengths and integrated cross sections for various excitations from the 2p 2( 3P O) valence state.

  5. Cross sections for electron scattering by atomic potassium

    SciTech Connect

    Msezane, A.Z.; Awuah, P.; Hiamang, S. Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, Georgia 30314 ); Allotey, F.K.A. )

    1992-12-01

    Electron elastic and collisional excitation cross sections from the ground state of potassium are calculated using the noniterative integral-equation method of Henry, Rountree, and Smith (Comput. Phys. Commun. 23, 233 (1981)) in the electron energy range 4{le}{ital E}{le}200 eV. Configuration-interaction target wave functions that take account of correlation and polarization effects are used to represent the ground state and the six lowest excited states 4{ital p} {sup 2}{ital P}{degree}, 5{ital s} {sup 2}{ital S}, 3{ital d} {sup 2}{ital D}, 5{ital p} {sup 2}{ital P}{degree}, 4{ital d} {sup 2}{ital D}, and 6{ital s} {sup 2}{ital S}. Elastic and discrete excitation cross sections are obtained in a seven-state close-coupling (7CC) approximation. The 7CC elastic and excitation cross sections are compared and contrasted. Near threshold the elastic cross section dominates the resonance, 4{ital s} {sup 2}{ital S}{r arrow}4{ital p} {sup 2}{ital P}{degree}, and the sum of the other remaining excitation cross sections. Comparison of our total cross sections with some available experimental and theoretical data is also effected. The discrepancy between the recent measurement of the total cross section by Kwan {ital et} {ital al}. (Phys. Rev. A 44, 1620 (1991)) on the one hand and other measurements near threshold on the other hand is explained.

  6. Postmastectomy Pain: A Cross-sectional Study of Prevalence, Pain Characteristics, and Effects on Quality of Life

    PubMed Central

    Beyaz, Serbülent Gökhan; Ergönenç, Jalan Şerbetçigil; Ergönenç, Tolga; Sönmez, Özlem Uysal; Erkorkmaz, Ünal; Altintoprak, Fatih

    2016-01-01

    Background: Postmastectomy pain syndrome (PMPS) is defined as a chronic (continuing for 3 or more months) neuropathic pain affecting the axilla, medial arm, breast, and chest wall after breast cancer surgery. The prevalence of PMPS has been reported to range from 20% to 68%. In this study, we aimed to determine the prevalence of PMPS among mastectomy patients, the severity of neuropathic pain in these patients, risk factors that contribute to pain becoming chronic, and the effect of PMPS on life quality. Methods: This cross-sectional study was approved by the Sakarya University, Medical Faculty Ethical Council and included 146 patients ranging in age from 18 to 85 years who visited the pain clinic, general surgery clinic, and oncology clinic and had breast surgery between 2012 and 2014. Patients were divided into two groups according to whether they met PMPS criteria: pain at axilla, arm, shoulder, chest wall, scar tissue, or breast at least 3 months after breast surgery. All patients gave informed consent prior to entry into the study. Patient medical records were collected, and pain and quality of life were evaluated by the visual analog scale (VAS) for pain, a short form of the McGill Pain Questionnaire (SF-MPQ), douleur neuropathique-4 (DN-4), and SF-36. Results: Patient mean age was 55.2 ± 11.8 years (33.0–83.0 years). PMPS prevalence was 36%. Mean scores on the VAS, SF-MPQ, and DN-4 in PMPS patients were 1.76 ± 2.38 (0–10), 1.73 ± 1.54 (0–5), and 1.64 ± 2.31 (0–8), respectively. Of these patients, 31 (23.7%) had neuropathic pain characteristics, and 12 (9.2%) had phantom pain according to the DN-4 survey. Patients who had modified radical mastectomy were significantly more likely to develop PMPS than patients who had breast-protective surgery (P = 0.028). Only 2 (2.4%) of PMPS patients had received proper treatment (anticonvulsants or opioids). Conclusions: PMPS seriously impacts patients’ emotional situation, daily activities, and social

  7. The possible absence of a healthy-worker effect: a cross-sectional survey among educated Japanese women

    PubMed Central

    Nishikitani, Mariko; Nakao, Mutsuhiro; Tsurugano, Shinobu; Yano, Eiji

    2012-01-01

    Objectives Despite being highly educated in comparison with women in other member countries of the Organisation for Economic Cooperation and Development, Japanese women are expected to assume traditional gender roles, and many dedicate themselves to full-time housewifery. Women working outside the home do so under poor conditions, and their health may not be better than that of housewives. This study compared the self-rated health status and health behaviours of housewives and working women in Japan. Design Cross-sectional survey. Setting A national university in Tokyo with 9864 alumnae. Participants A total 1344 women who graduated since 1985 and completed questionnaires in an anonymous mail-based survey. Primary and secondary outcome measures Health anxiety and satisfaction, receipt of health check-ups, eating breakfast, smoking, and sleep problems according to job status and family demands: housewives (n=247) and working women with (n=624) and without (n=436) family demands. ORs were used for risk assessment, with housewives as a reference. Results After adjustment for satisfaction with present employment status and other confounding factors, working women were more likely than housewives to feel health anxiety (with family demands, OR: 1.68, 95% CI1.10 to 2.57; without family demands, OR: 3.57, 95% CI 2.19 to 4.50) and health dissatisfaction (without family demands, OR: 3.50, 95% CI 2.35 to 5.21); they were also more likely than housewives to eat an insufficient breakfast (with family demands, OR: 1.91, 95% CI 1.22 to 3.00; without family demands, OR: 4.02, 95% CI 2.47 to 6.57) and to have sleep problems (ORs: 2.08 to 4.03). Conclusions No healthy-worker effect was found among Japanese women. Housewives, at least those who are well educated, appear to have better health status and health-related behaviours than do working women with the same level of education. PMID:22964114

  8. Molecular orientation effect on the differential cross sections for the electron-impact double ionization of oriented water molecules

    SciTech Connect

    Champion, C.; Dal Cappello, C.; Oubaziz, D.; Aouchiche, H.; Popov, Yu. V.

    2010-03-15

    Double ionization of isolated water molecules fixed in space is here investigated in a theoretical approach based on the first Born approximation. Secondary electron angular distributions are reported for particular (e,3e) kinematical conditions and compared in terms of shape and magnitude. Strong dependence of the fivefold differential cross sections on the molecular target orientation is clearly observed in (e,3-1e) as well as (e,3e) channels. Furthermore, for the major part of the kinematics considered, we identified the different mechanisms involved in the double ionization of water molecule, namely, the direct shake-off process as well as the two-step1 process. They are both discussed and analyzed with respect to the molecular target orientation.

  9. Effect of the variable cross-section channel on performance of a cusped field thruster at low power

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Chen, Pengbo; Mao, Wei; Yu, Daren; Wang, Chunsheng

    2015-09-01

    The cusped field thruster has drawn much attention from many institutions due to its wide thrust range, high impulse, and long lifetime. However, lots of experimental results reveal that the cusped field thruster at low power has a poor performance. A cusped field thruster with a variable cross-section channel by putting a ceramic spacer in the channel is introduced in this paper, aimed at improving the thruster performance at low power. The DSMC results validate that the upstream atom density can be increased by a spacer, especially near the wall. Based on simulated results, spacers are put into different positions of the channel. The experimental results show that a suitable spacer can enhance thruster performance at low power, which can be confirmed by the results that the anode efficiency can achieve 40% at 400 V anode voltage and 20 sccm gas flow rate by contrast to 35% without a spacer under the same condition.

  10. Modeling elastic momentum transfer cross-sections from mobility data

    NASA Astrophysics Data System (ADS)

    Nikitović, Ž. D.; Stojanović, V. D.; Raspopović, Z. M.

    2016-04-01

    In this letter we present a new method to simply obtain the elastic momentum transfer cross-section which predicts a maximum of reduced mobility and its sensitivity to the temperature variation at low energies. We first determined the transport cross-section which resembles mobility data for similar closed-shell systems by using the Monte Carlo method. Second, we selected the most probable reactive processes and compiled cross-sections from experimental and theoretical data. At the end, an elastic momentum transfer cross-section is obtained by subtracting the compiled cross-sections from the momentum transfer cross-section, taking into account the effects of the angular scattering distributions. Finally, the cross-section set determined in such a way is used as an input in a final Monte Carlo code run, to calculate the flux and bulk reduced mobility for Ne+ + CF4 which were discussed as functions of the reduced electric field E/N (N is the gas density) for the temperature T = 300 K.

  11. Differential double capture cross sections in p+He collisions

    SciTech Connect

    Schulz, M.; Brand, J. A.; Vajnai, T.

    2007-02-15

    We have measured differential double capture cross sections for 15 to 150 keV p+He collisions. We also analyzed differential double to single capture ratios, where we find pronounced peak structures. An explanation of these structures probably requires a quantum-mechanical description of elastic scattering between the projectile and the target nucleus. Strong final-state correlations have a large effect on the magnitude of the double capture cross sections.

  12. An Effective Field Theory Calculation of n(p, d)gamma Cross-section for Big Bang Nucleo-synthesis

    NASA Astrophysics Data System (ADS)

    Kamand, Rasha Adnan

    Studying the nuclear reaction n(p, d)gamma and calculating its cross-section is not only a matter of interest from theoretical particle physics point of view but also from the viewpoint of cosmology. We now know that the universe is made up of only ≈ 5% baryonic matter. So, computing the density of baryons is of particular importance to physicists in general and cosmologists in particular. Deuterium production during Big Bang Nucleo-synthesis (BBN) is very sensitive to the density of baryons, thus baryon density can be inferred from the abundance of deuterium. In order to calculate deuterium abundance one needs to use the cross-section of np --> dgamma reaction as one of the inputs; hence the importance of this cross-section calculation. In this document, a leading-order (LO) calculation of n( p, d)gamma cross-section is presented using the framework of pion-less effective field theory with dibaryon fields. The computation yielded a numerical value of sigmaLO = 494 mb which is then compared to the experimental value.

  13. Aspects of the momentum dependence of the equation of state and of the residual N N cross section, and their effects on nuclear stopping

    NASA Astrophysics Data System (ADS)

    Basrak, Z.; Eudes, P.; de la Mota, V.

    2016-05-01

    With the semiclassical Landau-Vlasov transport model we studied the stopping observable RE, the energy-based isotropy ratio, for the 129Xe+120Sn reaction at beam energies spanning 12 A to 100 A MeV. We investigated the impacts of the nonlocality of the nuclear mean field, of the in-medium modified nucleon-nucleon (N N ) cross section, and of the reaction centrality. A fixed set of model parameters yields RE values that favorably compare with the experimental ones, but only for energies below the Fermi energy EF. Above EF agreement is readily possible, but by a smooth evolution with energy of the parameter that controls the in-medium modification of N N cross section. By comparing the simulation correction factor F applied to the free N N cross section with the one deduced from experimental data [Phys. Rev. C 90, 064602 (2014), 10.1103/PhysRevC.90.064602], we infer that the zero-range mean field almost entirely reproduces it. Also, in accordance with what has been deduced from experimental data, around EF a strong reduction of the free N N cross section is found. In order to test the impact of sampling central collisions by multiplicity, an event generator (hipse) was used. We obtain that high multiplicity events are spread over a broad impact parameter range, but it turns out that this has a small effect on the observable RE and, thus, on F as well.

  14. Cross sections for actinide burner reactors

    SciTech Connect

    Difilippo, F.C.

    1991-01-01

    Recent studies have shown the feasibility of burning higher actinides (i.e., transuranium (TRU) elements excluding plutonium) in ad hoc designed reactors (Actinide Burner Reactors: ABR) which, because of their hard neutron spectra, enhance the fission of TRU. The transmutation of long-lived radionuclides into stable or short-lived isotopes reduces considerably the burden of handling high-level waste from either LWR or Fast Breeder Reactors (FBR) fuels. Because of the large concentrations of higher actinides in these novel reactor designs the Doppler effect due to TRU materials is the most important temperature coefficient from the point of view of reactor safety. Here we report calculations of energy group-averaged capture and fission cross sections as function of temperature and dilution for higher actinides in the resolved and unresolved resonance regions. The calculations were done with the codes SAMMY in the resolved region and URR in the unresolved regions and compared with an independent calculation. 4 refs., 2 figs., 2 tabs.

  15. Tables of nuclear cross sections for galactic cosmic rays: Absorption cross sections

    NASA Technical Reports Server (NTRS)

    Townsend, L. W.; Wilson, J. W.

    1985-01-01

    A simple but comprehensive theory of nuclear reactions is presented. Extensive tables of nucleon, deuteron, and heavy-ion absorption cross sections over a broad range of energies are generated for use in cosmic ray shielding studies. Numerous comparisons of the calculated values with available experimental data show agreement to within 3 percent for energies above 80 MeV/nucleon and within approximately 10 percent for energies as low as 30 MeV/nucleon. These tables represent the culmination of the development of the absorption cross section formalism and supersede the preliminary absorption cross sections published previously in NASA TN D-8107, NASA TP-2138, and NASA TM-84636.

  16. Absolute np and pp cross section determinations aimed at improving the standard for cross section measurements

    SciTech Connect

    Laptev, Alexander B; Haight, Robert C; Tovesson, Fredrik; Arndt, Richard A; Briscoe, William J; Paris, Mark W; Strakovsky, Igor I; Workman, Ron L

    2010-01-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1000 MeV are determined based on partial-wave analyses (PW As) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-V11.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  17. Absolute np and pp Cross Section Determinations Aimed At Improving The Standard For Cross Section Measurements

    SciTech Connect

    Laptev, A. B.; Haight, R. C.; Tovesson, F.; Arndt, R. A.; Briscoe, W. J.; Paris, M. W.; Strakovsky, I. I.; Workman, R. L.

    2011-06-01

    Purpose of present research is a keeping improvement of the standard for cross section measurements of neutron-induced reactions. The cross sections for np and pp scattering below 1 GeV are determined based on partial-wave analyses (PWAs) of nucleon-nucleon scattering data. These cross sections are compared with the most recent ENDF/B-VII.0 and JENDL-4.0 data files, and the Nijmegen PWA. Also a comparison of evaluated data with recent experimental data was made to check a quality of evaluation. Excellent agreement was found between the new experimental data and our PWA predictions.

  18. Calculation of improved spallation cross sections

    NASA Technical Reports Server (NTRS)

    Tsao, C. H.; Silberberg, R.; Letaw, J. R.

    1985-01-01

    Several research groups have recently carried out highly precise measurements (to about 10 percent) of high-energy nuclear spallation cross sections. These measurements, above 5 GeV, cover a broad range of elements: V, Fe, Cu, Ag, Ta and Au. Even the small cross sections far off the peak of the isotopic distribution curves have been measured. The semiempirical calculations are compared with the measured values. Preliminary comparisons indicate that the parameters of our spallation relations (Silberberg and Tsao, 1973) for atomic numbers 20 to 83 need modifications, e.g. a reduced slope of the mass yield distribution, broader isotopic distributions, and a shift of the isotopic distribution toward the neutron-deficient side. The required modifications are negligible near Fe and Cu, but increase with increasing target mass.

  19. Inclusive jet cross section measurement at CDF

    SciTech Connect

    Pagliarone, C.

    1996-08-01

    The CDF Collaboration has measured the inclusive jet cross section using 1992-93 collider data at 1.8 TeV. The CDF measurement is in very good agreement with NLO QCD predictions for transverse energies (E{sub T}) below 200 GeV. However, it is systematically higher than NLO QCD predictions for E{sub T} above 200 GeV.

  20. {sup 231}Pa photofission cross section

    SciTech Connect

    Soldatov, A.S.; Rudnikov, V.E.; Smirenkin, G.N.

    1995-12-01

    The measurements of the {sup 231}Pa yield and cross section photofission in the energy range 7-9 MeV are presented. These measurements are a continuation of similar measurements performed for the {gamma}-ray energy range 4.8-7 MeV. The entire collection of experimental data which combine the results obtained in the present work and in Ref. 1 was analyzed.

  1. Neutron cross section standards and instrumentation

    NASA Astrophysics Data System (ADS)

    1992-09-01

    This report from the National Institute of Standards and Technology contains a summary of the accomplishments of the Neutron Cross Section Standards and Instrumentation Project during the second year of a three-year interagency agreement. This program includes a broad range of data measurements and evaluations. An emphasis has been focused on the (sup 10)B cross sections where serious discrepancies in the nuclear data base remain. In particular, there are important problems with the interpretation of the helium gas production associated with diagnostic measurements of interest in nuclear technology. The enhanced use of this isotope for medical treatment is also of significance. New measurements of neutron reaction cross sections for (sup 10)B are in progress in collaboration with scientists at the Oak Ridge National Laboratory. New experiments are in progress on the important dosimetry standards (sup 237)Np(n,f) and (sup 239)Pu(n,f) below 1 MeV neutron energy. In addition, new measurements of charged-particle production in basic biological elements for medical applications are underway. Further measurements are planned or in progress in collaborations which include fission fragment energy and angular distributions, and neutron energy spectra and angular distributions from neutron-induced fission. Also measurements of angular distributions of neutrons from scattering on protons, and determinations of capture cross section of gold are planned for a later time. Data evaluation will shift to include a unified international effort to motivate new measurements and evaluations. In response to the requests of the measurement community, NIST is beginning the formation of a national depository for fissionable isotope mass standards. This action will preserve for future measurements the valuable and irreplaceable critical samples whose masses and composition have been carefully determined and documented over the past 30 years of the nuclear program.

  2. Inclusive jet cross section at D0

    SciTech Connect

    Bhattacharjee, M.

    1996-09-01

    Preliminary measurement of the central ({vert_bar}{eta}{vert_bar} {<=} 0.5) inclusive jet cross sections for jet cone sizes of 1.0, 0.7, and 0.5 at D{null} based on the 1992-1993 (13.7 {ital pb}{sup -1}) and 1994-1995 (90 {ital pb}{sup -1}) data samples are presented. Comparisons to Next-to-Leading Order (NLO) Quantum Chromodynamics (QCD) calculations are made.

  3. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1985-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

  4. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1982-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

  5. Fusion cross sections measurements with MUSIC

    NASA Astrophysics Data System (ADS)

    Carnelli, P. F. F.; Fernández Niello, J. O.; Almaraz-Calderon, S.; Rehm, K. E.; Albers, M.; Digiovine, B.; Esbensen, H.; Henderson, D.; Jiang, C. L.; Nusair, O.; Palchan-Hazan, T.; Pardo, R. C.; Ugalde, C.; Paul, M.; Alcorta, M.; Bertone, P. F.; Lai, J.; Marley, S. T.

    2014-09-01

    The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. The interaction between exotic nuclei plays an important role for understanding the reaction mechanism of the fusion processes as well as for the energy production in stars. With the advent of radioactive beams new frontiers for fusion reaction studies have become accessible. We have performed the first measurements of the total fusion cross sections in the systems 10 , 14 , 15C + 12C using a newly developed active target-detector system (MUSIC). Comparison of the obtained cross sections with theoretical predictions show a good agreement in the energy region accessible with existing radioactive beams. This type of comparison allows us to calibrate the calculations for cases that cannot be studied in the laboratory with the current experimental capabilities. The high efficiency of this active detector system will allow future measurements with even more neutron-rich isotopes. This work is supported by the U.S. DOE Office of Nuclear Physics under Contract No. DE-AC02-06CH11357 and the Universidad Nacional de San Martin, Argentina, Grant SJ10/39.

  6. How to Calculate Colourful Cross Sections Efficiently

    SciTech Connect

    Gleisberg, Tanju; Hoeche, Stefan; Krauss, Frank

    2008-09-03

    Different methods for the calculation of cross sections with many QCD particles are compared. To this end, CSW vertex rules, Berends-Giele recursion and Feynman-diagram based techniques are implemented as well as various methods for the treatment of colours and phase space integration. We find that typically there is only a small window of jet multiplicities, where the CSW technique has efficiencies comparable or better than both of the other two methods.

  7. Quality Quantification of Evaluated Cross Section Covariances

    SciTech Connect

    Varet, S.; Dossantos-Uzarralde, P.

    2015-01-15

    Presently, several methods are used to estimate the covariance matrix of evaluated nuclear cross sections. Because the resulting covariance matrices can be different according to the method used and according to the assumptions of the method, we propose a general and objective approach to quantify the quality of the covariance estimation for evaluated cross sections. The first step consists in defining an objective criterion. The second step is computation of the criterion. In this paper the Kullback-Leibler distance is proposed for the quality quantification of a covariance matrix estimation and its inverse. It is based on the distance to the true covariance matrix. A method based on the bootstrap is presented for the estimation of this criterion, which can be applied with most methods for covariance matrix estimation and without the knowledge of the true covariance matrix. The full approach is illustrated on the {sup 85}Rb nucleus evaluations and the results are then used for a discussion on scoring and Monte Carlo approaches for covariance matrix estimation of the cross section evaluations.

  8. Differential cross sections of positron–hydrogen collisions

    NASA Astrophysics Data System (ADS)

    Rong-Mei, Yu; Chun-Ying, Pu; Xiao-Yu, Huang; Fu-Rong, Yin; Xu-Yan, Liu; Li-Guang, Jiao; Ya-Jun, Zhou

    2016-07-01

    We make a detailed study on the angular differential cross sections of positron–hydrogen collisions by using the momentum-space coupled-channels optical (CCO) method for incident energies below the H ionization threshold. The target continuum and the positronium (Ps) formation channels are included in the coupled-channels calculations via a complex equivalent-local optical potential. The critical points, which show minima in the differential cross sections, as a function of the scattering angle and the incident energy are investigated. The resonances in the angular differential cross sections are reported for the first time in this energy range. The effects of the target continuum and the Ps formation channels on the different cross sections are discussed. Project supported by the Nanyang Normal University Science Foundation of China (Grant No. ZX2013017) and the National Natural Science Foundation of China (Grant Nos. 11174066, 61306007, and U1304114).

  9. Longitudinal and Cross-Sectional Analyses of Age Effects on Retinal Nerve Fiber Layer and Ganglion Cell Complex Thickness by Fourier-Domain OCT

    PubMed Central

    Zhang, Xinbo; Francis, Brian A.; Dastiridou, Anna; Chopra, Vikas; Tan, Ou; Varma, Rohit; Greenfield, David S.; Schuman, Joel S.; Huang, David

    2016-01-01

    Purpose We studied the effects of age and intraocular pressure (IOP) on retinal nerve fiber layer (NFL) and macular ganglion cell complex (GCC) thickness in normal eyes. Methods Data from subjects from the multicenter Advanced Imaging for Glaucoma Study (AIGS) were analyzed. The data included yearly visits from the normal subjects in the AIGS study. Fourier-domain optical coherence tomography (FD-OCT) was used to measure retinal NFL and macular GCC on each visit. Mixed effect models were used to evaluate the longitudinal effect of age and IOP on the NFL and GCC thickness. The measurements at baseline were used to examine the cross-sectional effects. Results The analysis included 192 eyes (92 participants) from AIGS between 2009 and 2013. The longitudinal analyses showed overall GCC thickness decreased 0.25 ± 0.05 μm per year (P < 0.001) while the overall NFL thickness decreased 0.14 ± 0.07 μm per year (P = 0.04). The cross-sectional analyses showed the GCC thickness was 0.17 ± 0.05 μm thinner per year of baseline age (P < 0.001), while the NFL was 0.21 ± 0.06 μm thinner (P < 0.001). There was no significant IOP effect on either GCC or NFL from either the longitudinal or cross-sectional analysis. Conclusions Longitudinal and cross-sectional analyses provided consistent rates of approximately 0.2% per year of age-related thinning in NFL and GCC thicknesses. This is relevant in establishing criteria to detect glaucoma-related thinning (disease progression) in excess of normal aging. IOP does not seem to be a significant confounder for progression analysis. Translational Relevance This study demonstrated the relevance of advanced imaging technology in diagnosing and monitoring glaucoma disease. PMID:26966637

  10. Mental visualization of objects from cross-sectional images

    PubMed Central

    Wu, Bing; Klatzky, Roberta L.; Stetten, George D.

    2011-01-01

    We extended the classic anorthoscopic viewing procedure to test a model of visualization of 3D structures from 2D cross-sections. Four experiments were conducted to examine key processes described in the model, localizing cross-sections within a common frame of reference and spatiotemporal integration of cross sections into a hierarchical object representation. Participants used a hand-held device to reveal a hidden object as a sequence of cross-sectional images. The process of localization was manipulated by contrasting two displays, in-situ vs. ex-situ, which differed in whether cross sections were presented at their source locations or displaced to a remote screen. The process of integration was manipulated by varying the structural complexity of target objects and their components. Experiments 1 and 2 demonstrated visualization of 2D and 3D line-segment objects and verified predictions about display and complexity effects. In Experiments 3 and 4, the visualized forms were familiar letters and numbers. Errors and orientation effects showed that displacing cross-sectional images to a remote display (ex-situ viewing) impeded the ability to determine spatial relationships among pattern components, a failure of integration at the object level. PMID:22217386

  11. Bias in cross-sectional analyses of longitudinal mediation.

    PubMed

    Maxwell, Scott E; Cole, David A

    2007-03-01

    Most empirical tests of mediation utilize cross-sectional data despite the fact that mediation consists of causal processes that unfold over time. The authors considered the possibility that longitudinal mediation might occur under either of two different models of change: (a) an autoregressive model or (b) a random effects model. For both models, the authors demonstrated that cross-sectional approaches to mediation typically generate substantially biased estimates of longitudinal parameters even under the ideal conditions when mediation is complete. In longitudinal models where variable M completely mediates the effect of X on Y, cross-sectional estimates of the direct effect of X on Y, the indirect effect of X on Y through M, and the proportion of the total effect mediated by M are often highly misleading. PMID:17402810

  12. Mass transfer through laminar boundary layer in 2-d microchannels with nonuniform cross section: the effect of wall curvature

    NASA Astrophysics Data System (ADS)

    Pedacchia, Augusta; Adrover, Alessandra

    2012-11-01

    We provide an analytical solution for the combined diffusive and convective 2-d mass transport from a surface film (of arbitrary shape at a given uniform concentration) to a pure solvent flowing in creeping flow conditions into a microchannel, delimited by a flat no-slip surface and by the releasing film itself. Such a problem arises in the study of swelling and dissolution of polimeric thin films under the action of a solvent tangential flow simulating the oral thin film dissolution for drug relase towards the buccal mucosa or oral cavity. We present a similarity solution for laminar forced convection mass (or heat) transfer that generalizes the classical boundary layer solution of the Graetz-Nusselt problem (valid for straight channels or pipes) to a solvent flowing in creeping flow conditions into a 2-d channel with cross-section continuously varying along the axial coordinate x. Close to the releasing boundary, parametrized by a curvilinear abscissa s, both tangential and normal velocity components play a role and their scaling behavior, as a function of wall distance r, should be taken into account in order to have an accurate description of the concentration profile in the boundary layer and of the dependence of the Sherwood number on the curvilinear abscissa s.

  13. Effect of time of exposure to environmental risk on the lung function of foundry workers: a cross-sectional study

    PubMed Central

    Vasconcelos de Moraes, Mônica; Padula, Rosimeire Simprini; Bernardes, Rosane Andrea Bretas; Negreiros, Alexandher; Chiavegato, Luciana Dias

    2016-01-01

    [Purpose] This cross-sectional study aimed to compare foundry workers of the metallurgical industry with high and low exposure time and with a control group. [Subject and Methods] The workers were evaluated for pulmonary function and peak expiratory flow (PEF), respiratory symptoms, smoking habits, and physical activity level. Descriptive statistical analysis and ANOVA one-way test were used. [Results] The mean age was 33.9 ± 8.25 years (18–59), pulmonary function: FVC: 95 ± 18% of predicted, FEV1: 95.0 ± 15.8% of predicted, FEV1/FVC ratio of 0.82 ± 0.09, and PEF = 499.7 ± 118.5 l/min. Overall, 85.1% of workers were classified that physically active, 7.93% of workers reported respiratory symptoms, and 14.28% reported being smokers. There was no statistically significant difference between groups for the variables of lung function. [Conclusion] The pulmonary function is preserved in foundry workers independently of exposure time. PMID:27064981

  14. Cross-sectional nanoindentation (CSN) studies on the effect of thickness on adhesion strength of thin films

    NASA Astrophysics Data System (ADS)

    Roshanghias, A.; Khatibi, G.; Pelzer, R.; Steinbrenner, J.; Bernardi, J.

    2015-01-01

    In this study the cross-sectional nanoindentation (CSN) technique has been employed to investigate the adhesion behavior of Titanium-Tungsten (TiW) thin films in various thicknesses on silicon substrate. Furthermore, the nanoindentation-induced blister (NIB) technique has been implemented on the same samples to evaluate the adhesion energy of the films with a different approach. The adhesion energy release rate of these thin films, derived by these two techniques, revealed a good agreement. Accordingly, the results show that as the thickness of the TiW layer increases, the adhesion toughness of the film decreases. It was suggested that three factors might be responsible for the superior adhesion strength of thin films with lower thicknesses: higher surface energy due to the smaller mean grain size; higher constraint from the substrate, which causes inferior fracture toughness of the coating and facilitates crack deflection from interface to surface; and, energy dissipation due to decohesion. The thickness dependency of the transition between delamination and decohesion mechanism in thin films has also been discussed and modelled.

  15. Effect of time of exposure to environmental risk on the lung function of foundry workers: a cross-sectional study.

    PubMed

    Vasconcelos de Moraes, Mônica; Padula, Rosimeire Simprini; Bernardes, Rosane Andrea Bretas; Negreiros, Alexandher; Chiavegato, Luciana Dias

    2016-01-01

    [Purpose] This cross-sectional study aimed to compare foundry workers of the metallurgical industry with high and low exposure time and with a control group. [Subject and Methods] The workers were evaluated for pulmonary function and peak expiratory flow (PEF), respiratory symptoms, smoking habits, and physical activity level. Descriptive statistical analysis and ANOVA one-way test were used. [Results] The mean age was 33.9 ± 8.25 years (18-59), pulmonary function: FVC: 95 ± 18% of predicted, FEV1: 95.0 ± 15.8% of predicted, FEV1/FVC ratio of 0.82 ± 0.09, and PEF = 499.7 ± 118.5 l/min. Overall, 85.1% of workers were classified that physically active, 7.93% of workers reported respiratory symptoms, and 14.28% reported being smokers. There was no statistically significant difference between groups for the variables of lung function. [Conclusion] The pulmonary function is preserved in foundry workers independently of exposure time. PMID:27064981

  16. Effective cross sections for production of single-strand breaks in plasmid DNA by 0.1 to 4.7 eV electrons.

    PubMed

    Panajotovic, Radmila; Martin, Frédéric; Cloutier, Pierre; Hunting, Darel; Sanche, Léon

    2006-04-01

    We determined effective cross sections for production of single-strand breaks (SSBs) in plasmid DNA [pGEM 3Zf(-)] by electrons of 10 eV and energies between 0.1 and 4.7 eV. After purification and lyophilization on a chemically clean tantalum foil, dry plasmid DNA samples were transferred into a high-vacuum chamber and bombarded by a monoenergetic electron beam. The amount of the circular relaxed DNA in the samples was separated from undamaged molecules and quantified using agarose gel electrophoresis. The effective cross sections were derived from the slope of the yield as a function of exposure and had values in the range of 10(-15)- 10(-14) cm2, giving an effective cross section of the order of 10(-18) cm2 per nucleotide. Their strong variation with incident electron energy and the resonant enhancement at 1 eV suggest that considerable damage is inflicted by very low-energy electrons to DNA, and it indicates the important role of pi* shape resonances in the bond-breaking process. Furthermore, the fact that the energy threshold for SSB production is practically zero implies that the sensitivity of DNA to electron impact is universal and is not limited to any particular energy range. PMID:16579658

  17. Updating the IST-LISBON electron cross sections for nitrogen

    NASA Astrophysics Data System (ADS)

    Alves, L. L.; Sombreireiro, L.; Viegas, P.; Guerra, V.

    2013-09-01

    In this work we update the complete and consistent set of nitrogen (N2) electron-impact cross-section with the IST-LISBON database, available on the LXCat website. The update has extended, in energy scale up to 1 keV, the cross sections for effective momentum-transfer, excitation to electronic states and ionization. The set further accounts for excitation to rotational and vibrational excited states. Calculations using BOLSIG + with the new cross sections give swarm parameters in very good agreement with available experimental data for the reduced mobility, the characteristic energy and the reduced ionization coefficient, for a very extended E / N range up to 1000 Td. The influence of rotational excitations/de-excitations at low E / N and different rotational temperatures is discussed. A critical evaluation of similarities and differences with sets of N2 cross sections from other databases is carried out. Moreover, the procedure to de-convolute global cross sections into state-to-state vibrational level dependent cross sections is outlined and discussed. Work partially supported by FCT (Pest-OE/SADG/LA0010/2011).

  18. Single electron capture cross sections for protons colliding with neon and methane targets: effects of the initial vibrational state of CH4

    NASA Astrophysics Data System (ADS)

    Cabrera-Trujillo, R.; Hernández, L.; Hernández, E. M.; Hinojosa, G.

    2016-02-01

    The process of neutralization of ions induced by collisions is crucial to understanding the chemical evolution of interstellar gas. However, the role of the initial vibrational state of the target molecule is not completely understood. In this work, we carry out a combined experimental and theoretical study of the vibrational target effects on the single electron charge exchange cross sections for protons colliding with CH4 in the keV energy region. We complement our study by analyzing the single electron capture from the iso-electronic neon atom to discern similarities and differences. For our experimental study, we use the growth-rate method for the determination of the single electron capture cross section on both systems. For the theoretical study, we use an electron-nuclear dynamics approach for the time evolution of the system wave function to find out the final projectile charge state. We report charge exchange probabilities and cross sections for H+ projectiles when colliding on both targets. We find that these ten-electron systems would have an asymptotically similar charge exchange cross section at high collision energies and would differentiate in the intermediate to low collision energies due to the energetics of the valence electrons and initial vibrational state. In the case of the protons colliding with CH4, we find that it is easier to capture an electron from a CH4 target than from the Ne. Furthermore, we find that low vibrational states have a higher contribution to the electron capture cross section as the collision energy is reduced. We stress the importance of taking into account the initial bending and stretching vibrational modes in the study of the electron capture process. For the neon target, the high ionization potential of the valence electrons produces a smaller charge exchange cross section for low proton collision energies when compared to the CH4 target. We report good comparison to available experimental data. We expect our findings

  19. Preliminary cross section of Englebright Lake sediments

    USGS Publications Warehouse

    Snyder, Noah P.; Hampton, Margaret A.

    2003-01-01

    Overview -- The Upper Yuba River Studies Program is a CALFED-funded, multidisciplinary investigation of the feasibility of introducing anadromous fish species to the Yuba River system upstream of Englebright Dam. Englebright Lake (Figure 1 on poster) is a narrow, 14-km-long reservoir located in the northern Sierra Nevada, northeast of Marysville, CA. The dam was completed in 1941 for the primary purpose of trapping sediment derived from mining operations in the Yuba River watershed. Possible management scenarios include lowering or removing Englebright Dam, which could cause the release of stored sediments and associated contaminants, such as mercury used extensively in 19th-century hydraulic gold mining. Transport of released sediment to downstream areas could increase existing problems including flooding and mercury bioaccumulation in sport fish. To characterize the extent, grain size, and chemistry of this sediment, a coring campaign was done in Englebright Lake in May and June 2002. More than twenty holes were drilled at 7 different locations along the longitudinal axis of the reservoir (Figure 4 on poster), recovering 6 complete sequences of post-reservoir deposition and progradation. Here, a longitudinal cross section of Englebright Lake is presented (Figure 5 on poster), including pre-dam and present-day topographic profiles, and sedimentologic sections for each coring site. This figure shows the deltaic form of the reservoir deposit, with a thick upper section consisting of sand and gravel overlying silt, a steep front, and a thinner lower section dominated by silt. The methodologies used to create the reservoir cross section are discussed in the lower part of this poster.

  20. Measured Absolute Cross Section of Charge Transfer in H + H2+ at Low Energy: Signature of vi = 2 and Trajectory Effects

    NASA Astrophysics Data System (ADS)

    Strom, R. A.; Bacani, K. G.; Chi, R. M.; Heczko, S. L.; Singh, B. N.; Tobar, J. A.; Vassantachart, A. K.; Andrianarijaona, V. M.; Seely, D. G.; Havener, C. C.

    2015-04-01

    Measurements of absolute cross sections of charge transfer (CT) in H + H2+--> H+ + H2 were conducted at the merged-beam apparatus at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, which can reliably create and access collision energies as low as 0.1 eV/u. The measured absolute cross section shows evidence of trajectory effects at low energy. Also, the comparison to state-to-state calculations (PRA 67 022708 (2003) suggests a strong contribution from vi = 2 of the H2+that are produced by the electron cyclotron resonance ion source. The data analysis will be presented here. Research supported by the NASA Solar & Heliospheric Physics Program NNH07ZDA001N, the Office of Fusion Energy Sciences and the Division of Chemical Sciences, Geosciences, and Biosciences, Office of Basic Energy Sciences of the U.S. Department of Energy, the National Science Foundation through Grant No. PHY-1068877.

  1. Exclusive breastfeeding and its effect on growth of Malawian infants: results from a cross-sectional study

    PubMed Central

    Kuchenbecker, J; Jordan, I; Reinbott, A; Herrmann, J; Jeremias, T; Kennedy, G; Muehlhoff, E; Mtimuni, B; Krawinkel, M B

    2015-01-01

    Background: For the optimal nutrition of children under 2 years of age, it is considered important that they be exclusively breastfed for the first 6 months before being given complementary food. Aims and Objectives: A cross-sectional nutritional baseline survey was undertaken in 2011 in the Kasungu and Mzimba Districts of Malawi to assess the nutritional status of children under 2 years of age and its determinants in order to prepare a nutrition education intervention programme. The intention of this study was to assess the nutritional status of infants aged 0–<6 months with regard to food intake. Methods: Interviews were conducted on randomly selected families with children under 2 years; anthropometric measurements were obtained from mothers and their children. Only infants between 0 and <6 months were selected for analysis (n  =  196). An ANCOVA test was performed on age of the infant with mothers’ height and weight as covariates. Results: Prevalence of stunting (infants’ length-for-age Z-score (LAZ) <−2SD) was 39%, wasting (WLZ <−2SD) 2%, and underweight (WAZ <−2SD) 13%. Of the infants under 6 months, 43% were exclusively breastfed. Predominant breastfeeding and mixed breastfeeding were less common (21% and 36%, respectively). The ANCOVA confirmed the association between exclusive breastfeeding and LAZ and WAZ: exclusively breastfed infants had a higher mean (SE) LAZ (−1·13, 0·12) and WAZ (−0·41, 0·13) than infants not being exclusively breastfed (−1·59, 0·11, and −0·97, 0·11, respectively). There was no overall significant association between breastfeeding practice and WLZ. Conclusion: Exclusive breastfeeding of infants under 6 months is associated with higher mean LAZ and WAZ. Promotion of exclusive breastfeeding in low-income countries is important in preventing growth retardation. PMID:25005815

  2. Effect of Pesticide Exposure on Immunological, Hematological and Biochemical Parameters in Thai Orchid Farmers—A Cross-Sectional Study

    PubMed Central

    Aroonvilairat, Soraya; Kespichayawattana, Wannapa; Sornprachum, Thiwaree; Chaisuriya, Papada; Siwadune, Taweeratana; Ratanabanangkoon, Kavi

    2015-01-01

    Various studies have found that many Thai orchid farmers used excessive amounts of pesticides without proper protective gear, but no toxicological study has been made. This cross-sectional study aimed to evaluate the immunological, hematological and biochemical statuses of these farmers. Sixty four orchid farmers and 60 controls were studied. Plasma cholinesterase activity, the percentage and absolute number of B lymphocytes (CD19+) were significantly lower in the farmers group (3966.32 ± 1165.48 U/L, 11.61 ± 4.09% and 312.26 ± 164.83 cells/mm3, respectively) as compared to those of controls (5048.85 ± 1139.40 U/L, 14.32 ± 4.23%, 420.34 ± 195.18 cells/mm3, respectively). There was a statistically significant higher level of serum IgE among the orchid farmers (0.031 ± 0.011 mg/dL vs. 0.018 ± 0.007 mg/dL) but not IgG, IgA and IgM, levels. Serum lysozyme level, lymphocyte proliferative responses to mitogens, hematological parameters and kidney function test, were not significantly different between the two groups. The liver function profiles showed significantly lower levels of albumin and serum protein in the farmer group. Thus frequent pesticide exposure resulted in subtle changes of some biological parameters. These changes, though may not be clinically significant, strongly indicated that caution in handing pesticides by these farmers is warranted. PMID:26024358

  3. Effect of restrictions on smoking at home, at school, and in public places on teenage smoking: cross sectional study

    PubMed Central

    Wakefield, Melanie A; Chaloupka, Frank J; Kaufman, Nancy J; Orleans, C Tracy; Barker, Dianne C; Ruel, Erin E

    2000-01-01

    Objective To determine the relation between extent of restrictions on smoking at home, at school, and in public places and smoking uptake and smoking prevalence among school students. Design Cross sectional survey with merged records of extent of restrictions on smoking in public places. Setting United States. Participants 17 287 high school students. Main outcome measures Five point scale of smoking uptake; 30 day smoking prevalence. Results More restrictive arrangements on smoking at home were associated with a greater likelihood of being in an earlier stage of smoking uptake (P<0.05) and a lower 30 day prevalence (odds ratio 0.79 (95% confidence interval 0.67 to 0.91), P<0.001). These findings applied even when parents were smokers. More pervasive restrictions on smoking in public places were associated with a higher probability of being in a earlier stage of smoking uptake (P<0.05) and lower 30 day prevalence (0.91 (0.83 to 0.99), P=0.03). School smoking bans were related to a greater likelihood of being in an earlier stage of smoking uptake (0.89 (0.85 to 0.99), P<0.05) and lower prevalence (0.86 (0.77 to 0.94), P<0.001) only when the ban was strongly enforced, as measured by instances when teenagers perceived that most or all students obeyed the rule. Conclusions These findings suggest that restrictions on smoking at home, more extensive bans on smoking in public places, and enforced bans on smoking at school may reduce teenage smoking. PMID:10926588

  4. Menopausal symptoms and its effect on quality of life in urban versus rural women: A cross-sectional study

    PubMed Central

    Sharma, Sudhaa; Mahajan, Neha

    2015-01-01

    Aim and Objective: To analyze the menopause-related symptoms and its impact on quality of life in post-menopausal women from urban and rural area. Materials and Methods: A cross-sectional 1-year study was carried among women of urban (n = 490) and rural (n = 380) areas, attending the outpatient department in the urban area and a house-to-house survey in rural areas, by interviews with the help of a pretested semi-structured standard questionnaire. For assessment of the menopausal symptoms menopause rating scale (MRS) and for quality of life, World Health Organization Quality of Life Scale (WHO QOL-BREF) questionnaire was used. Results: There was a significant difference between the MRS total scores of the urban (14.67 ± 6.64) and rural (16.08 ± 7.65) group. The somatic, psychological, and urogenital symptoms were high in rural women than in urban women. The results were not significant for urogenital subscale. The mean raw scores of physical health, psychological, social relationships, and environmental domains was more in urban than in rural women. The mean transformed scores (4-20) of physical health, psychological, social relationships, and environmental domains was more in urban than in rural women. The mean transformed scores (0-100) including the physical health, psychological, social relationships, and environmental domains was more in urban than in rural women. The result was not significant for physical health. Conclusion: The high proportions and the scores of MRS were observed in both rural and the urban women. The severity of symptoms was found more distressing for rural women. The quality of life in urban society was average and better than in rural women. PMID:25861203

  5. Body composition in children with juvenile idiopathic arthritis: effect of dietary intake of macronutrient: results from a cross sectional study

    PubMed Central

    Hari, Asmae; Rostom, Samira; Hassani, Asmae; El Badri, Dalal; Bouaadi, Ilham; Barakat, Amina; Chkirat, Bouchra; Elkari, Khalid; Amine, Bouchra; Hajjaj-Hassouni, Najia

    2015-01-01

    Introduction The aim of this study was to evaluate the relationship between macronutrient intake, body composition (lean body mass and fat mass) and bone mineral content in Moroccan children with juvenile idiopathic arthritis (JIA). Methods A cross-sectional study, conducted between May 2010 and June 2011, covering out patient with JIA. The characteristics of patients were collected. The nutritional status was assessed by a food questionnaire including data of food intake during 7 consecutive days using 24-hour dietary recall. Food intake was quantified using the software Bilnut (Bilnut version 2.01, 1991). Dietary intake of macronutrients was expressed as percentage contribution to total energy. Body composition was evaluated with DXA total-body measurements (bone mineral content BMC expressed in g, lean body mass LBM and fat mass FM expressed in kg). Results 33 patients were included. The mean age was 10.4 ± 4.3 years. The median disease duration was 2 (1-4.5) years. The median of LBM, FM and BMC were 19 kg (13.82-33.14), 5 kg (3.38-9.14) and 1044.90 g (630.40-1808.90) respectively. We found a positive correlation between LBM and dietary intake of carbohydrate (r= 0.4; p = 0.03). There were no significant association between LBM and intake of lipids, or protein. Moreover, no association was found between FM, BMC and intake of carbohydrates, lipids and proteins. Conclusion This study suggests that there is a positive correlation between carbohydrates intake and LBM; however, dietary intake does not influence FM and BMC. Prospective studies with larger numbers of patients appear to be needed to confirm our findings. PMID:26161167

  6. Averaging cross section data so we can fit it

    SciTech Connect

    Brown, D.

    2014-10-23

    The 56Fe cross section we are interested in have a lot of fluctuations. We would like to fit the average of the cross section with cross sections calculated within EMPIRE. EMPIRE is a Hauser-Feshbach theory based nuclear reaction code, requires cross sections to be smoothed using a Lorentzian profile. The plan is to fit EMPIRE to these cross sections in the fast region (say above 500 keV).

  7. The calculation of radar cross sections

    NASA Astrophysics Data System (ADS)

    Pizer, R.

    1980-04-01

    The FORTRAN program CHAOS, used for calculating cross sections is described including the physical approximations used to simplify Maxwell's equations. The scattering bodies are extended to both open and closed surfaces. The numerical methods used are supplied. The problems of wire junctions, of finite conductivity and the attaching of lumped loads to the structure are considered. Techniques for dealing with bodies having rotational or left-right symmetries are examined as well as the sparse matrix approximation and the complex frequency version of CHAOS. The formula used to calculate the impedance matrix elements, and the conventions adopted concerning coordinate systems and polarization are included.

  8. Correlation cross sections along the international border

    SciTech Connect

    Martiniuk, C.D. ); Le Fever, J.A.; Anderson, S.B. )

    1991-06-01

    The Manitoba-North Dakota (Canada-US) stratigraphic correlation project is a joint study between the Petroleum Branch of Manitoba Energy and Mines and the North Dakota Geological Survey. It is an attempt to correlate the differing stratigraphic terminologies established in the two jurisdictions by providing a reference cross section across the international boundary. The study involves the subsurface correlation of logs of the Paleozoic and Mesozoic sequences in the Manitoba and North Dakota portions of the Williston basin. The Paleozoic and Mesozoic sequences are subdivided for presentation into the following stratigraphic intervals: (a) Cambrian-Ordovician-Silurian, (b) Devonian, (c) Mississippian, (d) Jurassic, and (e) Cretaceous. Wireline logs show the actual stratigraphic correlations. A nomenclature chart is also presented from each sequence. In addition, the sections include a generalized description of lithologies, thicknesses, environments of deposition, and petroleum potential for each geographic area.

  9. Windowed multipole for cross section Doppler broadening

    NASA Astrophysics Data System (ADS)

    Josey, C.; Ducru, P.; Forget, B.; Smith, K.

    2016-02-01

    This paper presents an in-depth analysis on the accuracy and performance of the windowed multipole Doppler broadening method. The basic theory behind cross section data is described, along with the basic multipole formalism followed by the approximations leading to windowed multipole method and the algorithm used to efficiently evaluate Doppler broadened cross sections. The method is tested by simulating the BEAVRS benchmark with a windowed multipole library composed of 70 nuclides. Accuracy of the method is demonstrated on a single assembly case where total neutron production rates and 238U capture rates compare within 0.1% to ACE format files at the same temperature. With regards to performance, clock cycle counts and cache misses were measured for single temperature ACE table lookup and for windowed multipole. The windowed multipole method was found to require 39.6% more clock cycles to evaluate, translating to a 7.9% performance loss overall. However, the algorithm has significantly better last-level cache performance, with 3 fewer misses per evaluation, or a 65% reduction in last-level misses. This is due to the small memory footprint of the windowed multipole method and better memory access pattern of the algorithm.

  10. Actinide Targets for Neutron Cross Section Measurements

    SciTech Connect

    John D. Baker; Christopher A. McGrath

    2006-10-01

    The Advanced Fuel Cycle Initiative (AFCI) and the Generation IV Reactor Initiative have demonstrated a lack of detailed neutron cross-sections for certain "minor" actinides, those other than the most common (235U, 238U, and 239Pu). For some closed-fuel-cycle reactor designs more than 50% of reactivity will, at some point, be derived from "minor" actinides that currently have poorly known or in some cases not measured (n,?) and (n,f) cross sections. A program of measurements under AFCI has begun to correct this. One of the initial hurdles has been to produce well-characterized, highly isotopically enriched, and chemically pure actinide targets on thin backings. Using a combination of resurrected techniques and new developments, we have made a series of targets including highly enriched 239Pu, 240Pu, and 242Pu. Thus far, we have electrodeposited these actinide targets. In the future, we plan to study reductive distillation to achieve homogeneous, adherent targets on thin metal foils and polymer backings. As we move forward, separated isotopes become scarcer, and safety concerns become greater. The chemical purification and electodeposition techniques will be described.