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Sample records for partial body ionizing

  1. Physics of Partially Ionized Plasmas

    NASA Astrophysics Data System (ADS)

    Krishan, Vinod

    2016-05-01

    Figures; Preface; 1. Partially ionized plasmas here and everywhere; 2. Multifluid description of partially ionized plasmas; 3. Equilibrium of partially ionized plasmas; 4. Waves in partially ionized plasmas; 5. Advanced topics in partially ionized plasmas; 6. Research problems in partially ionized plasmas; Supplementary matter; Index.

  2. Effects of dose and of partial body ionizing radiation on taste aversion learning in rats with lesions of the area postrema

    SciTech Connect

    Rabin, B.M.; Hunt, W.A.; Lee, J. )

    1984-01-01

    The effect of area postrema lesions on the acquisition of a conditioned taste aversion following partial body exposure to ionizing radiation was investigated in rats exposed to head-only irradiation at 100, 200 and 300 rad or to body-only irradiation at 100 and 200 rad. Following head-only irradiation area postrema lesions produced a significant attenuation of the radiation-induced taste aversion at all dose levels, although the rats still showed a significant reduction in sucrose preference. Following body-only exposure, area postrema lesions completely disrupted the acquisition of the conditioned taste aversion. The results are interpreted as indicating that: (a) the acquisition of a conditioned taste aversion following body-only exposure is mediated by the area postrema; and (b) taste aversion learning following radiation exposure to the head-only is mediated by both the area postrema and a mechanism which is independent of the area postrema.

  3. Ionization of xenon by electrons: Partial cross sections for single, double, and triple ionization

    SciTech Connect

    Mathur, D.; Badrinathan, C.

    1987-02-01

    High-sensitivity measurements of relative partial cross sections for single, double, and triple ionization of Xe by electron impact have been carried out in the energy region from threshold to 100 eV using a crossed-beam apparatus incorporating a quadrupole mass spectrometer. The weighted sum of the relative partial cross sections at 50 eV are normalized to the total ionization cross section of Rapp and Englander-Golden to yield absolute cross-section functions. Shapes of the partial cross sections for single and double ionization are difficult to account for within a single-particle picture. Comparison of the Xe/sup +/ data with 4d partial photoionization cross-section measurements indicates the important role played by many-body effects in describing electron-impact ionization of high-Z atoms.

  4. Thermal conductivity of partially ionized gas mixtures

    NASA Astrophysics Data System (ADS)

    Armaly, B. F.; Sutton, K.

    1981-06-01

    A method is proposed for predicting the translational component of the thermal conductivity of partially ionized gas mixtures. It is approximate but simple in form and offers a significant improvement over commonly utilized approximations. It does not require large computer run times nor storage, thus it is suitable for use with complex flow fields and heat transfer calculations. Results for gas mixtures which are representative of the atmosphere of Jupiter, Earth, and Venus are presented and they compare favorably with results from detailed kinetic theory analyses.

  5. Viscosity of multicomponent partially ionized gas mixtures

    NASA Astrophysics Data System (ADS)

    Armaly, B. F.; Sutton, K.

    1980-07-01

    An approximate method is proposed for predicting the viscosity of partially ionized gas mixtures. This technique expresses the viscosity of a mixture in terms of the viscosities of the individual pure components, is simple in form, and does not require large computer run times or storage. Thus, the technique is suitable for use with complex flowfields and heat-transfer calculations. Results for gas mixtures which are representative of the atmospheres of Jupiter, Earth, and Venus, are presented and it is shown that the results compare favorably with detailed kinetic-theory analyses.

  6. Partially ionized plasmas, including the Third Symposium on Uranium Plasmas

    NASA Technical Reports Server (NTRS)

    Krishnan, M.

    1976-01-01

    Fundamentals of both electrically and fission generated plasmas are discussed. Research in gaseous fuel reactors using uranium hexafluoride is described and other partially ionized plasma applications are discussed.

  7. Influence of renormalization shielding on the electron-impact ionization process in dense partially ionized plasmas

    SciTech Connect

    Song, Mi-Young; Yoon, Jung-Sik; Jung, Young-Dae

    2015-04-15

    The renormalization shielding effects on the electron-impact ionization of hydrogen atom are investigated in dense partially ionized plasmas. The effective projectile-target interaction Hamiltonian and the semiclassical trajectory method are employed to obtain the transition amplitude as well as the ionization probability as functions of the impact parameter, the collision energy, and the renormalization parameter. It is found that the renormalization shielding effect suppresses the transition amplitude for the electron-impact ionization process in dense partially ionized plasmas. It is also found that the renormalization effect suppresses the differential ionization cross section in the peak impact parameter region. In addition, it is found that the influence of renormalization shielding on the ionization cross section decreases with an increase of the relative collision energy. The variations of the renormalization shielding effects on the electron-impact ionization cross section are also discussed.

  8. ALFVEN WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA

    SciTech Connect

    Soler, R.; Ballester, J. L.; Terradas, J.; Carbonell, M. E-mail: joseluis.ballester@uib.es E-mail: marc.carbonell@uib.es

    2013-04-20

    Alfven waves are a particular class of magnetohydrodynamic waves relevant in many astrophysical and laboratory plasmas. In partially ionized plasmas the dynamics of Alfven waves is affected by the interaction between ionized and neutral species. Here we study Alfven waves in a partially ionized plasma from the theoretical point of view using the two-fluid description. We consider that the plasma is composed of an ion-electron fluid and a neutral fluid, which interact by means of particle collisions. To keep our investigation as general as possible, we take the neutral-ion collision frequency and the ionization degree as free parameters. First, we perform a normal mode analysis. We find the modification due to neutral-ion collisions of the wave frequencies and study the temporal and spatial attenuation of the waves. In addition, we discuss the presence of cutoff values of the wavelength that constrain the existence of oscillatory standing waves in weakly ionized plasmas. Later, we go beyond the normal mode approach and solve the initial-value problem in order to study the time-dependent evolution of the wave perturbations in the two fluids. An application to Alfven waves in the low solar atmospheric plasma is performed and the implication of partial ionization for the energy flux is discussed.

  9. ONSET OF FAST MAGNETIC RECONNECTION IN PARTIALLY IONIZED GASES

    SciTech Connect

    Malyshkin, Leonid M.; Zweibel, Ellen G. E-mail: zweibel@astro.wisc.edu

    2011-10-01

    We consider quasi-stationary two-dimensional magnetic reconnection in a partially ionized incompressible plasma. We find that when the plasma is weakly ionized and the collisions between the ions and the neutral particles are significant, the transition to fast collisionless reconnection due to the Hall effect in the generalized Ohm's law is expected to occur at much lower values of the Lundquist number, as compared to a fully ionized plasma case. We estimate that these conditions for fast reconnection are satisfied in molecular clouds and in protostellar disks.

  10. MAGNETOACOUSTIC WAVES IN A PARTIALLY IONIZED TWO-FLUID PLASMA

    SciTech Connect

    Soler, Roberto; Ballester, Jose Luis; Carbonell, Marc E-mail: joseluis.ballester@uib.es

    2013-11-01

    Compressible disturbances propagate in a plasma in the form of magnetoacoustic waves driven by both gas pressure and magnetic forces. In partially ionized plasmas the dynamics of ionized and neutral species are coupled due to ion-neutral collisions. As a consequence, magnetoacoustic waves propagating through a partially ionized medium are affected by ion-neutral coupling. The degree to which the behavior of the classic waves is modified depends on the physical properties of the various species and on the relative value of the wave frequency compared to the ion-neutral collision frequency. Here, we perform a comprehensive theoretical investigation of magnetoacoustic wave propagation in a partially ionized plasma using the two-fluid formalism. We consider an extensive range of values for the collision frequency, ionization ratio, and plasma β, so that the results are applicable to a wide variety of astrophysical plasmas. We determine the modification of the wave frequencies and study the frictional damping due to ion-neutral collisions. Approximate analytic expressions for the frequencies are given in the limit case of strongly coupled ions and neutrals, while numerically obtained dispersion diagrams are provided for arbitrary collision frequencies. In addition, we discuss the presence of cutoffs in the dispersion diagrams that constrain wave propagation for certain combinations of parameters. A specific application to propagation of compressible waves in the solar chromosphere is given.

  11. Shock-wave structure in a partially ionized gas

    NASA Technical Reports Server (NTRS)

    Lu, C. S.; Huang, A. B.

    1974-01-01

    The structure of a steady plane shock in a partially ionized gas has been investigated using the Boltzmann equation with a kinetic model as the governing equation and the discrete ordinate method as a tool. The effects of the electric field induced by the charge separation on the shock structure have also been studied. Although the three species of an ionized gas travel with approximately the same macroscopic velocity, the individual distribution functions are found to be very different. In a strong shock the atom distribution function may have double peaks, while the ion distribution function has only one peak. Electrons are heated up much earlier than ions and atoms in a partially ionized gas. Because the interactions of electrons with atoms and with ions are different, the ion temperature can be different from the atom temperature.

  12. Neutral Atom Diffusion in a Partially Ionized Prominence Plasma

    NASA Technical Reports Server (NTRS)

    Gilbert, Holly

    2010-01-01

    The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized. it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material,

  13. The role of partial ionization effects in the chromosphere.

    PubMed

    Martínez-Sykora, Juan; De Pontieu, Bart; Hansteen, Viggo; Carlsson, Mats

    2015-05-28

    The energy for the coronal heating must be provided from the convection zone. However, the amount and the method by which this energy is transferred into the corona depend on the properties of the lower atmosphere and the corona itself. We review: (i) how the energy could be built in the lower solar atmosphere, (ii) how this energy is transferred through the solar atmosphere, and (iii) how the energy is finally dissipated in the chromosphere and/or corona. Any mechanism of energy transport has to deal with the various physical processes in the lower atmosphere. We will focus on a physical process that seems to be highly important in the chromosphere and not deeply studied until recently: the ion-neutral interaction effects in the chromosphere. We review the relevance and the role of the partial ionization in the chromosphere and show that this process actually impacts considerably the outer solar atmosphere. We include analysis of our 2.5D radiative magnetohydrodynamic simulations with the Bifrost code (Gudiksen et al. 2011 Astron. Astrophys. 531, A154 (doi:10.1051/0004-6361/201116520)) including the partial ionization effects on the chromosphere and corona and thermal conduction along magnetic field lines. The photosphere, chromosphere and transition region are partially ionized and the interaction between ionized particles and neutral particles has important consequences on the magneto-thermodynamics of these layers. The partial ionization effects are treated using generalized Ohm's law, i.e. we consider the Hall term and the ambipolar diffusion (Pedersen dissipation) in the induction equation. The interaction between the different species affects the modelled atmosphere as follows: (i) the ambipolar diffusion dissipates magnetic energy and increases the minimum temperature in the chromosphere and (ii) the upper chromosphere may get heated and expanded over a greater range of heights. These processes reveal appreciable differences between the modelled atmospheres

  14. The role of partial ionization effects in the chromosphere

    PubMed Central

    Martínez-Sykora, Juan; De Pontieu, Bart; Hansteen, Viggo; Carlsson, Mats

    2015-01-01

    The energy for the coronal heating must be provided from the convection zone. However, the amount and the method by which this energy is transferred into the corona depend on the properties of the lower atmosphere and the corona itself. We review: (i) how the energy could be built in the lower solar atmosphere, (ii) how this energy is transferred through the solar atmosphere, and (iii) how the energy is finally dissipated in the chromosphere and/or corona. Any mechanism of energy transport has to deal with the various physical processes in the lower atmosphere. We will focus on a physical process that seems to be highly important in the chromosphere and not deeply studied until recently: the ion–neutral interaction effects in the chromosphere. We review the relevance and the role of the partial ionization in the chromosphere and show that this process actually impacts considerably the outer solar atmosphere. We include analysis of our 2.5D radiative magnetohydrodynamic simulations with the Bifrost code (Gudiksen et al. 2011 Astron. Astrophys. 531, A154 (doi:10.1051/0004-6361/201116520)) including the partial ionization effects on the chromosphere and corona and thermal conduction along magnetic field lines. The photosphere, chromosphere and transition region are partially ionized and the interaction between ionized particles and neutral particles has important consequences on the magneto-thermodynamics of these layers. The partial ionization effects are treated using generalized Ohm's law, i.e. we consider the Hall term and the ambipolar diffusion (Pedersen dissipation) in the induction equation. The interaction between the different species affects the modelled atmosphere as follows: (i) the ambipolar diffusion dissipates magnetic energy and increases the minimum temperature in the chromosphere and (ii) the upper chromosphere may get heated and expanded over a greater range of heights. These processes reveal appreciable differences between the modelled

  15. Approximate Thermodynamics State Relations in Partially Ionized Gas Mixtures

    SciTech Connect

    Ramshaw, J D

    2003-12-30

    In practical applications, the thermodynamic state relations of partially ionized gas mixtures are usually approximated in terms of the state relations of the pure partially ionized constituent gases or materials in isolation. Such approximations are ordinarily based on an artificial partitioning or separation of the mixture into its constituent materials, with material k regarded as being confined by itself within a compartment or subvolume with volume fraction {alpha}k and possessing a fraction {beta}k of the total internal energy of the mixture. In a mixture of N materials, the quantities {alpha}k and {beta}k constitute an additional 2N--2 independent variables. The most common procedure for determining these variables, and hence the state relations for the mixture, is to require that the subvolumes all have the same temperature and pressure. This intuitively reasonable procedure is easily shown to reproduce the correct thermal and caloric state equations for a mixture of neutral (non-ionized) ideal gases. Here we wish to point out that (a) this procedure leads to incorrect state equations for a mixture of partially ionized ideal gases, whereas (b) the alternative procedure of requiring that the subvolumes all have the same temperature and free electron density reproduces the correct thermal and caloric state equations for such a mixture. These results readily generalize to the case of partially degenerate and/or relativistic electrons, to a common approximation used to represent pressure ionization effects, and to two-temperature plasmas. This suggests that equating the subvolume electron number densities or chemical potentials instead of pressures is likely to provide a more accurate approximation even in nonideal plasma mixtures.

  16. The role of partial ionization effects in the chromosphere

    NASA Astrophysics Data System (ADS)

    Martínez-Sykora, Juan; De Pontieu, Bart; Hansteen, Viggo; Carlsson, Mats

    2015-04-01

    The energy for the coronal heating must be provided from the convection zone. However, the amount and the method by which this energy is transferred into the corona depend on the properties of the lower atmosphere and the corona itself. We review: (i) how the energy could be built in the lower solar atmosphere, (ii) how this energy is transferred through the solar atmosphere, and (iii) how the energy is finally dissipated in the chromosphere and/or corona. Any mechanism of energy transport has to deal with the various physical processes in the lower atmosphere. We will focus on a physical process that seems to be highly important in the chromosphere and not deeply studied until recently: the ion-neutral interaction effects in the chromosphere. We review the relevance and the role of the partial ionization in the chromosphere and show that this process actually impacts considerably the outer solar atmosphere. We include analysis of our 2.5D radiative magnetohydrodynamic simulations with the Bifrost code (Gudiksen et al. 2011 Astron. Astrophys. 531, A154 (doi:10.1051/0004-6361/201116520)) including the partial ionization effects on the chromosphere and corona and thermal conduction along magnetic field lines. The photosphere, chromosphere and transition region are partially ionized and the interaction between ionized particles and neutral particles has important consequences on the magneto-thermodynamics of these layers. The partial ionization effects are treated using generalized Ohm's law, i.e. we consider the Hall term and the ambipolar diffusion (Pedersen dissipation) in the induction equation. The interaction between the different species affects the modelled atmosphere as follows: (i) the ambipolar diffusion dissipates magnetic energy and increases the minimum temperature in the chromosphere and (ii) the upper chromosphere may get heated and expanded over a greater range of heights. These processes reveal appreciable differences between the modelled atmospheres

  17. Equation of state of partially-ionized dense plasmas

    SciTech Connect

    Rogers, F.J.

    1989-09-28

    This paper describes methods for calculating the equation of state of partially-ionized dense plasmas. The term dense plasma is used rather than strongly coupled plasma, since it is possible that at plasma conditions such that only a few levels can be observed spectroscopically the plasma coupling parameters are not large. Due mainly to their importance in theoretical astrophysics, the properties of partially ionized plasmas have been of interest for a long while. More recently, this interest has intensified due to the development of methods for producing partially ionized plasmas in the laboratory. This has opened up large programs of experimental investigation and of practical application. In this paper we consider detailed statistical mechanical methods that explicitly treat the distribution over ionic species and their energy level structure. These detailed approaches are generally characterized as being in the chemical picture'' when a free energy expression is minimized or in the physical picture'' when the starting point is the grand canonical ensemble. 52 refs., 2 tabs.

  18. Quantum statistical mechanics of dense partially ionized hydrogen

    NASA Technical Reports Server (NTRS)

    Dewitt, H. E.; Rogers, F. J.

    1972-01-01

    The theory of dense hydrogen plasmas beginning with the two component quantum grand partition function is reviewed. It is shown that ionization equilibrium and molecular dissociation equilibrium can be treated in the same manner with proper consideration of all two-body states. A quantum perturbation expansion is used to give an accurate calculation of the equation of state of the gas for any degree of dissociation and ionization. The statistical mechanical calculation of the plasma equation of state is intended for stellar interiors. The general approach is extended to the calculation of the equation of state of the outer layers of large planets.

  19. Molecular Dynamics Description of Partially Ionized Dense Plasmas

    NASA Astrophysics Data System (ADS)

    Lagattuta, Ken

    2004-11-01

    A report on work in progress: the approach to steady-state of partially ionized dense plasmas, containing more than one atomic element, is being simulated with the quasi-classical method known as Fermi Molecular Dynamics (FMD). We recap the FMD method, recalling its several advantages and disadvantages, and present an overview of past work. we have continued to develop the FMD method as a tool for simulating the behaviors of a variety of inhomogeneous, partially ionized, dense plasma systems, in cases for which more rigorous methods are still unavailable. Predictions of the average ionization state Z* of atoms, in a plasma containing more than one atomic element, is complicated by many factors, especially under conditions of high density, and not too high temperature. Average atom models become problematic when two or more atomic elements are present together. In order to address this problem, we have applied the FMD method to plasmas containing selected mixtures of atomic elements, determining Z* for each element over a range of temperatures and densities. LANL archived abstract: LA-UR-04-2186

  20. Self-consistent chemical model of partially ionized plasmas

    SciTech Connect

    Arkhipov, Yu. V.; Baimbetov, F. B.; Davletov, A. E.

    2011-01-15

    A simple renormalization theory of plasma particle interactions is proposed. It primarily stems from generic properties of equilibrium distribution functions and allows one to obtain the so-called generalized Poisson-Boltzmann equation for an effective interaction potential of two chosen particles in the presence of a third one. The same equation is then strictly derived from the Bogolyubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy for equilibrium distribution functions in the pair correlation approximation. This enables one to construct a self-consistent chemical model of partially ionized plasmas, correctly accounting for the close interrelation of charged and neutral components thereof. Minimization of the system free energy provides ionization equilibrium and, thus, permits one to study the plasma composition in a wide range of its parameters. Unlike standard chemical models, the proposed one allows one to study the system correlation functions and thereby to obtain an equation of state which agrees well with exact results of quantum-mechanical activity expansions. It is shown that the plasma and neutral components are strongly interrelated, which results in the short-range order formation in the corresponding subsystem. The mathematical form of the results obtained enables one to both firmly establish this fact and to determine a characteristic length of the structure formation. Since the cornerstone of the proposed self-consistent chemical model of partially ionized plasmas is an effective pairwise interaction potential, it immediately provides quite an efficient calculation scheme not only for thermodynamical functions but for transport coefficients as well.

  1. Fluid description of multi-component solar partially ionized plasma

    SciTech Connect

    Khomenko, E. Collados, M.; Vitas, N.; Díaz, A.

    2014-09-15

    We derive self-consistent formalism for the description of multi-component partially ionized solar plasma, by means of the coupled equations for the charged and neutral components for an arbitrary number of chemical species, and the radiation field. All approximations and assumptions are carefully considered. Generalized Ohm's law is derived for the single-fluid and two-fluid formalism. Our approach is analytical with some order-of-magnitude support calculations. After general equations are developed, we particularize to some frequently considered cases as for the interaction of matter and radiation.

  2. Transport equations for partially ionized reactive plasma in magnetic field

    NASA Astrophysics Data System (ADS)

    Zhdanov, V. M.; Stepanenko, A. A.

    2016-06-01

    Transport equations for partially ionized reactive plasma in magnetic field taking into account the internal degrees of freedom and electronic excitation of plasma particles are derived. As a starting point of analysis the kinetic equation with a binary collision operator written in the Wang-Chang and Uhlenbeck form and with a reactive collision integral allowing for arbitrary chemical reactions is used. The linearized variant of Grad's moment method is applied to deduce the systems of moment equations for plasma and also full and reduced transport equations for plasma species nonequilibrium parameters.

  3. Quantum statistical mechanics of dense partially ionized hydrogen.

    NASA Technical Reports Server (NTRS)

    Dewitt, H. E.; Rogers, F. J.

    1972-01-01

    The theory of dense hydrogenic plasmas beginning with the two component quantum grand partition function is reviewed. It is shown that ionization equilibrium and molecular dissociation equilibrium can be treated in the same manner with proper consideration of all two-body states. A quantum perturbation expansion is used to give an accurate calculation of the equation of state of the gas for any degree of dissociation and ionization. In this theory, the effective interaction between any two charges is the dynamic screened potential obtained from the plasma dielectric function. We make the static approximation; and we carry out detailed numerical calculations with the bound and scattering states of the Debye potential, using the Beth-Uhlenbeck form of the quantum second virial coefficient. We compare our results with calculations from the Saha equation.

  4. The Effects of Partial Ionization on Prominence Mass Formation

    NASA Astrophysics Data System (ADS)

    Karpen, J. T.; Olson, K.; DeVore, C. R.; Martinez Gomez, D.; Sokolov, I.

    2015-12-01

    The origin of the prominence mass has been an open question since this cool plasma suspended in the hot corona was first discovered. We have known for a long time that the mass must come from the chromosphere, but it is unclear whether this mass is lifted bodily through magnetic levitation, injected by reconnection-driven upflows, or driven from the chromosphere by evaporation and then condensed. One evaporation-condensation scenario, the thermal nonequilibrium (TNE) model, is the most fully developed, quantitative model for the prominence plasma to date. In the TNE scenario, localized heating concentrated at the coronal loop footpoints produces chromospheric evaporation, filling the flux tube with hot, dense plasma that subsequently collapses radiatively to form cool condensations. Thus far this model has been successful in explaining the key properties of the long, persistent threads and small, highly dynamic, transient blobs in prominences, the damping of large-amplitude field-aligned prominence oscillations, the appearance of horn-shaped features above the cool prominence in EUV images of coronal cavities, and coronal rain in the ambient corona. To date, all studies of TNE have assumed that the plasma is fully ionized, which is appropriate for the hot coronal gas but unrealistic for the cool plasma below ~30,000 K. The energetics, dynamics, and evolutionary time scales of the TNE process are expected to be altered when the effects of ionization and recombination are considered. We have modified ARGOS, our 1D hydrodynamic code with adaptive mesh refinement, to include an equation of state that accounts for the effects of partial ionization of the plasma over a wide range of temperatures and densities. We will discuss the results of these simulations and their comparison with our previous studies of TNE in typical filament-supporting flux tubes. This work was partially supported by NASA's LWS Strategic Capability program.

  5. Equilibrium structures in partially ionized rotating plasmas within Hall magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Krishan, V.; Yoshida, Z.

    2006-09-01

    The formation of equilibrium structures in partially ionized rotating plasmas, consisting of electrons, ions, and neutral molecules, including the Hall effect, is studied in order to diagnose the possible velocity and the magnetic field configurations in a self-consistent manner. A few simple examples show that the linear and the nonlinear force-free magnetic configurations along with essentially nonlinear Beltrami flow field seem to be the general features of plasmas in the special case of the Keplerian rotation relevant for astrophysical plasmas. Thus rotation along with axial bipolar flows emerges as a natural pattern in gravitationally controlled magnetohydrodynamic systems. However, the equilibrium conditions permit more general flow and the magnetic field profiles that can perhaps be fully explored numerically. A special class of equilibria with unit magnetic Prandtl number and equal values of the fractional ion mass density α =ρi/ρn and the Hall parameter ɛ =λi/L exists where ρ's are the uniform mass densities, λi is the ion inertial scale, and L is the scale of the equilibrium structure. An approximate scaling law between the ionization fraction and the scale of the structure is found. Further by expressing the not so well known ionization fraction in terms of the temperature of the system, assuming thermal equilibrium, relationships among the extensive parameters such as the scale, the neutral particle density, the flow velocity, the temperature, and the magnetic field of the equilibrium structure can be determined. There seems to be a good overlap between the Hall and the thermal equilibria. The validity of the neglect of the ion dynamics is discussed.

  6. Collisionless Shocks in a Partially Ionized Medium. II. Balmer Emission

    NASA Astrophysics Data System (ADS)

    Morlino, G.; Bandiera, R.; Blasi, P.; Amato, E.

    2012-12-01

    Strong shocks propagating into a partially ionized medium are often associated with optical Balmer lines. This emission is due to impact excitation of neutral hydrogen by hot protons and electrons in the shocked gas. The structure of such Balmer-dominated shocks has been computed in a previous paper, where the distribution function of neutral particles was derived from the appropriate Boltzmann equation including coupling with ions and electrons through charge exchange and ionization. This calculation showed how the presence of neutrals can significantly modify the shock structure through the formation of a neutral-induced precursor ahead of the shock. Here we follow up on our previous work and investigate the properties of the resulting Balmer emission, with the aim of using the observed radiation as a diagnostic tool for shock parameters. Our main focus is on supernova remnant shocks, and we find that, for typical parameters, the Hα emission typically has a three-component spectral profile, where (1) a narrow component originates from upstream cold hydrogen atoms, (2) a broad component comes from hydrogen atoms that have undergone charge exchange with shocked protons downstream of the shock, and (3) an intermediate component is due to hydrogen atoms that have undergone charge exchange with warm protons in the neutral-induced precursor. The relative importance of these three components depends on the shock velocity, on the original degree of ionization, and on the electron-ion temperature equilibration level. The intermediate component, which is the main signature of the presence of a neutral-induced precursor, becomes negligible for shock velocities <~ 1500 km s-1. The width of the intermediate line reflects the temperature in the precursor, while the width of the narrow one is left unaltered by the precursor. In addition, we show that the profiles of both the intermediate and broad components generally depart from a thermal distribution, as a consequence of the

  7. Transport properties of partially ionized and unmagnetized plasmas

    NASA Astrophysics Data System (ADS)

    Magin, Thierry E.; Degrez, Gérard

    2004-10-01

    This work is a comprehensive and theoretical study of transport phenomena in partially ionized and unmagnetized plasmas by means of kinetic theory. The pros and cons of different models encountered in the literature are presented. A dimensional analysis of the Boltzmann equation deals with the disparity of mass between electrons and heavy particles and yields the epochal relaxation concept. First, electrons and heavy particles exhibit distinct kinetic time scales and may have different translational temperatures. The hydrodynamic velocity is assumed to be identical for both types of species. Second, at the hydrodynamic time scale the energy exchanged between electrons and heavy particles tends to equalize both temperatures. Global and species macroscopic fluid conservation equations are given. New constrained integral equations are derived from a modified Chapman-Enskog perturbative method. Adequate bracket integrals are introduced to treat thermal nonequilibrium. A symmetric mathematical formalism is preferred for physical and numerical standpoints. A Laguerre-Sonine polynomial expansion allows for systems of transport to be derived. Momentum, mass, and energy fluxes are associated to shear viscosity, diffusion coefficients, thermal diffusion coefficients, and thermal conductivities. A Goldstein expansion of the perturbation function provides explicit expressions of the thermal diffusion ratios and measurable thermal conductivities. Thermal diffusion terms already found in the Russian literature ensure the exact mass conservation. A generalized Stefan-Maxwell equation is derived following the method of Kolesnikov and Tirskiy. The bracket integral reduction in terms of transport collision integrals is presented in Appendix for the thermal nonequilibrium case. A simple Eucken correction is proposed to deal with the internal degrees of freedom of atoms and polyatomic molecules, neglecting inelastic collisions. The authors believe that the final expressions are

  8. Fluid Dynamical Instabilities in a Partially Ionized Flow

    NASA Astrophysics Data System (ADS)

    Kamaya, Hideyuki; Nishi, Ryoichi

    2000-05-01

    In this paper, we reveal that there are two fluid dynamical instabilities for a partially ionized flow with quasi-static contraction: the instability of the Alfvén wave and the two-fluid instability. We find them by means of linear perturbation analysis, adopting the following unperturbed state; the magnetic field has a gradient against the terminal flow of neutrals, which are accelerated because of gravity. The terminal velocity is determined by the balance between the gravity and the friction force, which originates from the ion-neutral collisions. The instability of the Alfvén wave occurs because of the imbalance of the restoring force, which is generated by the unperturbed background magnetic field if a wavelength is longer than a critical wavelength. Indeed, this critical wavelength is obtained from the comparison between the local restoring efficiency and that of the background unperturbed field. It is estimated as of the order of ~0.01 pc when the grains are the dominant charged particles. Thus, we speculate that this instability is responsible for the formation of the observed small-scale structure in the molecular clouds. If the relative speed between the ions and the neutrals is larger than the thermal speed of the neutrals, there is another instability, i.e., the so-called two-fluid instability. Fortunately, although the two-fluid instability coexists with the instability of the Alfvén wave, structure formation via the instability of the Alfvén wave is possible since its growth rate is larger than that of the two-fluid instability.

  9. Diagnosis of partial body radiation exposure in mice using peripheral blood gene expression profiles.

    PubMed

    Meadows, Sarah K; Dressman, Holly K; Daher, Pamela; Himburg, Heather; Russell, J Lauren; Doan, Phuong; Chao, Nelson J; Lucas, Joseph; Nevins, Joseph R; Chute, John P

    2010-01-01

    In the event of a terrorist-mediated attack in the United States using radiological or improvised nuclear weapons, it is expected that hundreds of thousands of people could be exposed to life-threatening levels of ionizing radiation. We have recently shown that genome-wide expression analysis of the peripheral blood (PB) can generate gene expression profiles that can predict radiation exposure and distinguish the dose level of exposure following total body irradiation (TBI). However, in the event a radiation-mass casualty scenario, many victims will have heterogeneous exposure due to partial shielding and it is unknown whether PB gene expression profiles would be useful in predicting the status of partially irradiated individuals. Here, we identified gene expression profiles in the PB that were characteristic of anterior hemibody-, posterior hemibody- and single limb-irradiation at 0.5 Gy, 2 Gy and 10 Gy in C57Bl6 mice. These PB signatures predicted the radiation status of partially irradiated mice with a high level of accuracy (range 79-100%) compared to non-irradiated mice. Interestingly, PB signatures of partial body irradiation were poorly predictive of radiation status by site of injury (range 16-43%), suggesting that the PB molecular response to partial body irradiation was anatomic site specific. Importantly, PB gene signatures generated from TBI-treated mice failed completely to predict the radiation status of partially irradiated animals or non-irradiated controls. These data demonstrate that partial body irradiation, even to a single limb, generates a characteristic PB signature of radiation injury and thus may necessitate the use of multiple signatures, both partial body and total body, to accurately assess the status of an individual exposed to radiation. PMID:20634956

  10. TRIAGE DOSE ASSESSMENT FOR PARTIAL-BODY EXPOSURE: DICENTRIC ANALYSIS

    PubMed Central

    Moroni, Maria; Pellmar, Terry C.

    2009-01-01

    Partial-body biodosimetry is likely to be required after a radiological or nuclear exposure. Clinical signs and symptoms, distribution of dicentrics in circulating blood cells, organ-specific biomarkers, physical signals in teeth and nails all can provide indications of non-homogeneous exposures. Organ specific biomarkers may provide early warning regarding physiological systems at risk after radiation injury. Use of a combination of markers and symptoms will be needed for clinical insights for therapeutic approaches. Analysis of dicentrics, a marker specific for radiation injury, is the “Gold standard” of biodosimetry and can reveal partial-body exposures. Automation of sample processing for dicentric analysis can increase throughput with customization of off-the-shelf technologies for cytogenetic sample processing and information management. Automated analysis of the metaphase spreads is currently limited but improvements are in development. Our efforts bridge the technological gaps to allow the use of dicentric chromosome assay (DCA) for risk-based stratification of mass casualties. This article summarizes current knowledge on partial-body cytogenetic dose assessment synthesizing information leading to the proposal of an approach to triage dose prediction in radiation mass casualties, based on equivalent whole-body doses under partial-body exposure conditions and assesses the validity of using this model. An initial screening using only 20 metaphase spreads per subject can confirm irradiation above 2-Gy. A subsequent increase to 50 metaphases improves dose determination to allow risk stratification for clinical triage. Metaphases evaluated for inhomogeneous distribution of dicentrics can reveal partial-body exposures. We tested the validity of this approach in an in vitro model that simulates partial-body irradiation by mixing irradiated and un-irradiated lymphocytes in various proportions. Our preliminary results support the notion that this approach will

  11. Influence of resonant charge exchange on the viscosity of partially ionized plasma in a magnetic field

    SciTech Connect

    Zhdanov, V. M. Stepanenko, A. A.

    2013-12-15

    The influence of resonant charge exchange for ion-atom interaction on the viscosity of partially ionized plasma embedded in the magnetic field is investigated. The general system of equations used to derive the viscosity coefficients for an arbitrary plasma component in the 21-moment approximation of Grad’s method is presented. The expressions for the coefficients of total and partial viscosities of a multicomponent partially ionized plasma in the magnetic field are obtained. As an example, the coefficients of the parallel and transverse viscosities for the ionic and neutral components of the partially ionized hydrogen plasma are calculated. It is shown that the account for resonant charge exchange can lead to a substantial change of the parallel and transverse viscosity of the plasma components in the region of low degrees of ionization on the order of 0.1.

  12. Kinetic theory of partially ionized complex (dusty) plasmas

    SciTech Connect

    Tsytovich, V.N.; De Angelis, U.; Ivlev, A.V.; Morfill, G.E.

    2005-08-15

    The general approach to the kinetic theory of complex (dusty) plasmas [Tsytovich and de Angelis, Phys. Plasmas 6, 1093 (1999)], which was formulated with the assumption of a regular (nonfluctuating) source of plasma particles, is reformulated to include ionization by electron impact on neutrals as the plasma source and the effects of collisions of ions and dust particles with neutrals.

  13. Perpendicular currents and electric fields in fully and partially ionized magnetized plasma

    SciTech Connect

    Rozhansky, V.

    2013-10-15

    Perpendicular currents and self-consistent electric fields in fully and partially ionized plasma in strong magnetic field are analyzed. In fully ionized plasma, the analyses are concentrated on closing of viscosity driven currents. For partially ionized plasma, it is demonstrated that the perpendicular currents could be expressed through the total pressure gradient (including the pressure gradient of neutral particles) and viscosity of neutrals. The self-consistent electric fields and corresponding E(vector sign)×B(vector sign) could be quite large, which is important for various applications, in particular, for the divertor plasma of a tokamak in the detached regime.

  14. Taste aversions conditioned with partial body radiation exposures

    SciTech Connect

    Smith, J.C.; Hollander, G.R.; Spector, A.C. . Dept. of Psychology)

    1981-11-01

    Radiation-induced taste aversion was compared in rats which received partial body exposure to the head or abdomen with rats receiving whole body irradiation. Exposure levels ranged from 25 to 300 roentgens (R). In additional groups, saccharin aversion to partial body gamma ray exposures of the abdomen were conditioned in animals which had prior experience with the saccharin solution. Aversion was measured with a single-bottle short-term test, a 23-hour preference test and by the number of days taken to recover from the aversion. Whole-body exposure was most effective in conditioning the aversion, and exposure of the abdominal area was more effective than exposure to the head. Also, the higher the exposure, the stronger the aversion. Rats receiving prior experience with the saccharin did not condition as well as control rats with no prior saccharin experience. The possible role of radiation-induced taste aversion in human radiotherapy patients was discussed.

  15. HEATING OF THE MAGNETIZED SOLAR CHROMOSPHERE BY PARTIAL IONIZATION EFFECTS

    SciTech Connect

    Khomenko, E.; Collados, M.

    2012-03-10

    In this paper, we study the heating of the magnetized solar chromosphere induced by the large fraction of neutral atoms present in this layer. The presence of neutrals, together with the decrease with height of the collisional coupling, leads to deviations from the classical magnetohydrodynamic behavior of the chromospheric plasma. A relative net motion appears between the neutral and ionized components, usually referred to as ambipolar diffusion. The dissipation of currents in the chromosphere is enhanced by orders of magnitude due to the action of ambipolar diffusion, as compared with the standard ohmic diffusion. We propose that a significant amount of magnetic energy can be released to the chromosphere just by existing force-free 10-40 G magnetic fields there. As a consequence, we conclude that ambipolar diffusion is an important process that should be included in chromospheric heating models, as it has the potential to rapidly heat the chromosphere. We perform analytical estimations and numerical simulations to prove this idea.

  16. Heating of ions by low-frequency Alfven waves in partially ionized plasmas

    SciTech Connect

    Dong Chuanfei; Paty, Carol S.

    2011-03-15

    In the solar atmosphere, the chromospheric and coronal plasmas are much hotter than the visible photosphere. The heating of the solar atmosphere, including the partially ionized chromosphere and corona, remains largely unknown. In this letter, we demonstrate that the ions can be substantially heated by Alfven waves with very low frequencies in partially ionized low-beta plasmas. This differs from other Alfven wave related heating mechanisms such as ion-neutral collisional damping of Alfven waves and heating described by previous work on resonant Alfven wave heating. We find that the nonresonant Alfven wave heating is less efficient in partially ionized plasmas than when there are no ion-neutral collisions, and the heating efficiency depends on the ratio of the ion-neutral collision frequency to the ion gyrofrequency.

  17. The effect of recombination radiation on the temperature and ionization state of partially ionized gas

    NASA Astrophysics Data System (ADS)

    Raičević, Milan; Pawlik, Andreas H.; Schaye, Joop; Rahmati, Alireza

    2014-01-01

    A substantial fraction of all ionizing photons originate from radiative recombinations. However, in radiative transfer calculations this recombination radiation is often assumed to be absorbed `on-the-spot' because for most methods the computational cost associated with the inclusion of gas elements as sources is prohibitive. We present a new, CPU and memory efficient implementation for the transport of ionizing recombination radiation in the TRAPHIC radiative transfer scheme. TRAPHIC solves the radiative transfer equation by tracing photon packets at the speed of light and in a photon-conserving manner in spatially adaptive smoothed particle hydrodynamics simulations. Our new implementation uses existing features of the TRAPHIC scheme to add recombination radiation at no additional cost in the limit in which the fraction of the simulation box filled with radiation approaches 1. We test the implementation by simulating an H II region in photoionization equilibrium and comparing to reference solutions presented in the literature, finding excellent agreement. We apply our implementation to discuss the evolution of the H II region to equilibrium. We show that the widely used case A and B approximations yield accurate ionization profiles only near the source and near the ionization front, respectively. We also discuss the impact of recombination radiation on the geometry of shadows behind optically thick absorbers. We demonstrate that the shadow region may be completely ionized by the diffuse recombination radiation field and discuss the important role of heating by recombination radiation in the shadow region.

  18. Application of the partial-Fourier-transform approach for tunnel ionization of molecules

    NASA Astrophysics Data System (ADS)

    Liu, Mingming; Liu, Yunquan

    2016-04-01

    Combining the partial-Fourier-transform approach with Wenzel-Kramers-Brillouin approximation, we theoretically study the strong-field tunneling ionization of diatomic and polyatomic molecules. First we obtain the analytical expression of momentum distribution at the tunnel exit of diatomic molecules, and then we calculate the alignment-dependent ionization rate at different laser intensities and internuclear distances. We show that the internuclear distance has a significant effect on the alignment dependence of the ionization rate. Using this approach, we can also separate the contributions of each atomic center and show the interference effect between them. Finally, we extend this method to a polyatomic molecule, benzene, as an example.

  19. Chromosome aberrations in relation to radiation dose following partial-body exposures in three populations

    SciTech Connect

    Kleinerman, R.A.; Littlefield, L.G.; Tarone, R.E.; Sayer, A.M.; Hildreth, N.G.; Pottern, L.M.; Machado, S.G.; Boice, J.D. Jr. )

    1990-07-01

    Structural chromosome aberrations were evaluated in peripheral blood samples obtained from three populations exposed to partial-body irradiation. These included 143 persons who received radiotherapy for enlarged thymus glands during infancy and 50 sibling controls; 79 persons irradiated for enlarged tonsils and 81 persons surgically treated for the same condition during childhood; and 77 women frequently exposed as young adults to fluoroscopic chest X rays during lung collapse treatment for tuberculosis (TB) and 66 women of similar ages treated for TB with other therapies. Radiation exposures occurred 30 and more years before blood was drawn. Doses to active bone marrow averaged over the entire body were 21, 6, and 14 cGy for the exposed thymic, tonsil, and TB subjects, respectively. Two hundred metaphases were scored for each subject, and the frequencies of symmetrical (stable) and asymmetrical (unstable) chromosome aberrations were quantified in 97,200 metaphases. Cells with stable aberrations were detected with greater frequency in the irradiated subjects compared with nonirradiated subjects in all three populations, and an overall test for an association between stable aberrations and partial-body ionizing radiation was highly significant (P less than 0.001). We found no evidence that radiation-induced aberrations varied by age at exposure. These data show that exposure of children or young adults to partial-body fractionated radiation can result in detectable increased frequencies of stable chromosome aberrations in circulating lymphocytes 30 years later, and that these aberrations appear to be informative as biological markers of population exposure.

  20. nMHDust: A 4-Fluid Partially Ionized Dusty Plasma Code

    NASA Astrophysics Data System (ADS)

    Lazerson, Samuel

    2008-11-01

    nMHDust is a next generation 4-fluid partially ionized magnetized dusty plasma code, treating the inertial dynamics of dust, ion and neutral components. Coded in ANSI C, the numerical method is based on the MHDust 3-fluid fully ionized dusty plasma code. This code expands the features of the MHDust code to include ionization/recombination effects and the netCDF data format. Tests of this code include: ionization instabilities, wave mode propagation (electromagnetic and acoustic), shear-flow instabilities, and magnetic reconnection. Relevant parameters for the space environment are considered, allowing a comparison to be made with previous dusty plasma codes (MHDust and DENISIS). The utility of the code is expanded through the possibility of a small dust mass. This allows nMHDust to be used as a 2-ion plasma code. nMHDust completes the array of fluid dusty plasma codes available for numerical investigations into nonlinear phenomena in the field of astrophysical dusty plasmas.

  1. Magnetic evidence for a partially differentiated carbonaceous chondrite parent body

    PubMed Central

    Carporzen, Laurent; Weiss, Benjamin P.; Elkins-Tanton, Linda T.; Shuster, David L.; Ebel, Denton; Gattacceca, Jérôme

    2011-01-01

    The textures of chondritic meteorites demonstrate that they are not the products of planetary melting processes. This has long been interpreted as evidence that chondrite parent bodies never experienced large-scale melting. As a result, the paleomagnetism of the CV carbonaceous chondrite Allende, most of which was acquired after accretion of the parent body, has been a long-standing mystery. The possibility of a core dynamo like that known for achondrite parent bodies has been discounted because chondrite parent bodies are assumed to be undifferentiated. Resolution of this conundrum requires a determination of the age and timescale over which Allende acquired its magnetization. Here, we report that Allende’s magnetization was acquired over several million years (Ma) during metasomatism on the parent planetesimal in a >  ∼ 20 μT field up to approximately 9—10 Ma after solar system formation. This field was present too recently and directionally stable for too long to have been generated by the protoplanetary disk or young Sun. The field intensity is in the range expected for planetesimal core dynamos, suggesting that CV chondrites are derived from the outer, unmelted layer of a partially differentiated body with a convecting metallic core.

  2. Equation of state for partially ionized carbon and oxygen mixtures at high temperatures

    SciTech Connect

    Massacrier, Gerard; Potekhin, Alexander Y.; Chabrier, Gilles

    2011-11-15

    The equation of state (EOS) for partially ionized carbon, oxygen, and carbon-oxygen mixtures at temperatures 3x10{sup 5} K < or approx. T < or approx. 3x10{sup 6} K is calculated over a wide range of densities, using the method of free energy minimization in the framework of the chemical picture of plasmas. The free energy model is an improved extension of our model previously developed for pure carbon [Potekhin, Massacrier, and Chabrier, Phys. Rev. E 72, 046402 (2005)]. The internal partition functions of bound species are calculated by a self-consistent treatment of each ionization stage in the plasma environment taking into account pressure ionization. The long-range Coulomb interactions between ions and screening of the ions by free electrons are included using our previously published analytical model, recently improved, in particular for the case of mixtures. We also propose a simple but accurate method of calculation of the EOS of partially ionized binary mixtures based on detailed ionization balance calculations for pure substances.

  3. Equation of state for partially ionized carbon and oxygen mixtures at high temperatures

    NASA Astrophysics Data System (ADS)

    Massacrier, Gérard; Potekhin, Alexander Y.; Chabrier, Gilles

    2011-11-01

    The equation of state (EOS) for partially ionized carbon, oxygen, and carbon-oxygen mixtures at temperatures 3×105K≲T≲3×106 K is calculated over a wide range of densities, using the method of free energy minimization in the framework of the chemical picture of plasmas. The free energy model is an improved extension of our model previously developed for pure carbon [Potekhin, Massacrier, and Chabrier, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.72.046402 72, 046402 (2005)]. The internal partition functions of bound species are calculated by a self-consistent treatment of each ionization stage in the plasma environment taking into account pressure ionization. The long-range Coulomb interactions between ions and screening of the ions by free electrons are included using our previously published analytical model, recently improved, in particular for the case of mixtures. We also propose a simple but accurate method of calculation of the EOS of partially ionized binary mixtures based on detailed ionization balance calculations for pure substances.

  4. Kinetic theory of transport processes in partially ionized reactive plasma, I: General transport equations

    NASA Astrophysics Data System (ADS)

    Zhdanov, V. M.; Stepanenko, A. A.

    2016-03-01

    In this paper we derive the set of general transport equations for multicomponent partially ionized reactive plasma in the presence of electric and magnetic fields taking into account the internal degrees of freedom and electronic excitation of plasma particles. Our starting point is a generalized Boltzmann equation with the collision integral in the Wang-Chang and Uhlenbeck form and a reactive collision integral. We obtain a set of conservation equations for such plasma and employ a linearized variant of Grad's moment method to derive the system of moment (or transport) equations for the plasma species nonequilibrium parameters. Full and reduced transport equations, resulting from the linearized system of moment equations, are presented, which can be used to obtain transport relations and expressions for transport coefficients of electrons and heavy plasma particles (molecules, atoms and ions) in partially ionized reactive plasma.

  5. The electromagnetic interchange mode in a partially ionized collisional plasma. [spread F region

    NASA Technical Reports Server (NTRS)

    Hudson, M. K.; Kennel, C. F.

    1974-01-01

    A collisional electromagnetic dispersion relation is derived from two-fluid theory for the interchange mode coupled to the Alfven, acoustic, drift and entropy modes in a partially ionized plasma. The fundamental electromagnetic nature of the interchange model is noted; coupling to the intermediate Alfven mode is strongly stabilizing for finite k sub z. Both ion viscous and ion-neutral stabilization are included, and it was found that collisions destroy the ion finite Larmor radius cutoff at short perpendicular wavelengths.

  6. Screening of ionic cores in partially ionized plasmas within linear response

    SciTech Connect

    Gericke, D. O.; Vorberger, J.; Wuensch, K.; Gregori, G.

    2010-06-15

    We employ a pseudopotential approach to investigate the screening of ionic cores in partially ionized plasmas. Here, the effect of the tightly bound electrons is condensed into an effective potential between the (free) valence electrons and the ionic cores. Even for weak electron-ion coupling, the corresponding screening clouds show strong modifications from the Debye result for elements heavier than helium. Modifications of the theoretically predicted x-ray scattering signal and implications on measurements are discussed.

  7. Basic results on the equations of magnetohydrodynamics of partially ionized inviscid plasmas

    SciTech Connect

    Nunez, Manuel

    2009-10-15

    The equations of evolution of partially ionized plasmas have been far more studied in one of their many simplifications than in its original form. They present a relation between the velocity of each species, plus the magnetic and electric fields, which yield as an analog of Ohm's law a certain elliptic equation. Therefore, the equations represent a functional evolution system, not a classical one. Nonetheless, a priori estimates and theorems of existence may be obtained in appropriate Sobolev spaces.

  8. Diamagnetic Effect in a Partially-Ionized High-Beta Plasma

    NASA Astrophysics Data System (ADS)

    Fruchtman, Amnon; Shinohara, Shunjiro

    2015-11-01

    Balance between magnetic pressure and plasma pressure is expected in fully ionized plasmas confined by a magnetic field. The magnetic force on the plasma is due to a current carried by the plasma which is diamagnetic. The magnetic field inside the plasma is then lowered by that current. In a partially-ionized plasma, however, the plasma pressure is balanced not only by the magnetic field pressure but also by neural-gas pressure. In that case the diamagnetic effect of the plasma, even if high beta, is expected to be lower. We calculate the steady-state of a cylindrical low temperature magnetized partially-ionized plasma (such as rf plasma source). We solve for the radial dependencies of the plasma density, the neutral density, and the magnetic field profile. Neutral pressure gradient is established by neutral depletion under the plasma pressure. We demonstrate how neutral depletion affects the diamagnetic effect of a high beta plasma. This work was partially supported by JSPS, Japan, and by ISF, Israel.

  9. Damping of Magnetohydrodynamic Turbulence in Partially Ionized Plasma: Implications for Cosmic Ray Propagation

    NASA Astrophysics Data System (ADS)

    Xu, Siyao; Yan, Huirong; Lazarian, A.

    2016-08-01

    We study the damping processes of both incompressible and compressible magnetohydrodynamic (MHD) turbulence in a partially ionized medium. We start from the linear analysis of MHD waves, applying both single-fluid and two-fluid treatments. The damping rates derived from the linear analysis are then used in determining the damping scales of MHD turbulence. The physical connection between the damping scale of MHD turbulence and the cutoff boundary of linear MHD waves is investigated. We find two branches of slow modes propagating in ions and neutrals, respectively, below the damping scale of slow MHD turbulence, and offer a thorough discussion of their propagation and dissipation behavior. Our analytical results are shown to be applicable in a variety of partially ionized interstellar medium (ISM) phases and the solar chromosphere. The importance of neutral viscosity in damping the Alfvenic turbulence in the interstellar warm neutral medium and the solar chromosphere is demonstrated. As a significant astrophysical utility, we introduce damping effects to the propagation of cosmic rays in partially ionized ISM. The important role of turbulence damping in both transit-time damping and gyroresonance is identified.

  10. DNA Damage Focus Analysis in Blood Samples of Minipigs Reveals Acute Partial Body Irradiation

    PubMed Central

    Lamkowski, Andreas; Forcheron, Fabien; Agay, Diane; Ahmed, Emad A.; Drouet, Michel; Meineke, Viktor; Scherthan, Harry

    2014-01-01

    Radiation accidents frequently involve acute high dose partial body irradiation leading to victims with radiation sickness and cutaneous radiation syndrome that implements radiation-induced cell death. Cells that are not lethally hit seek to repair ionizing radiation (IR) induced damage, albeit at the expense of an increased risk of mutation and tumor formation due to misrepair of IR-induced DNA double strand breaks (DSBs). The response to DNA damage includes phosphorylation of histone H2AX in the vicinity of DSBs, creating foci in the nucleus whose enumeration can serve as a radiation biodosimeter. Here, we investigated γH2AX and DNA repair foci in peripheral blood lymphocytes of Göttingen minipigs that experienced acute partial body irradiation (PBI) with 49 Gy (±6%) Co-60 γ-rays of the upper lumbar region. Blood samples taken 4, 24 and 168 hours post PBI were subjected to γ-H2AX, 53BP1 and MRE11 focus enumeration. Peripheral blood lymphocytes (PBL) of 49 Gy partial body irradiated minipigs were found to display 1–8 DNA damage foci/cell. These PBL values significantly deceed the high foci numbers observed in keratinocyte nuclei of the directly γ-irradiated minipig skin regions, indicating a limited resident time of PBL in the exposed tissue volume. Nonetheless, PBL samples obtained 4 h post IR in average contained 2.2% of cells displaying a pan-γH2AX signal, suggesting that these received a higher IR dose. Moreover, dispersion analysis indicated partial body irradiation for all 13 minipigs at 4 h post IR. While dose reconstruction using γH2AX DNA repair foci in lymphocytes after in vivo PBI represents a challenge, the DNA damage focus assay may serve as a rapid, first line indicator of radiation exposure. The occurrence of PBLs with pan-γH2AX staining and of cells with relatively high foci numbers that skew a Poisson distribution may be taken as indicator of acute high dose partial body irradiation, particularly when samples are available early after

  11. DNA damage focus analysis in blood samples of minipigs reveals acute partial body irradiation.

    PubMed

    Lamkowski, Andreas; Forcheron, Fabien; Agay, Diane; Ahmed, Emad A; Drouet, Michel; Meineke, Viktor; Scherthan, Harry

    2014-01-01

    Radiation accidents frequently involve acute high dose partial body irradiation leading to victims with radiation sickness and cutaneous radiation syndrome that implements radiation-induced cell death. Cells that are not lethally hit seek to repair ionizing radiation (IR) induced damage, albeit at the expense of an increased risk of mutation and tumor formation due to misrepair of IR-induced DNA double strand breaks (DSBs). The response to DNA damage includes phosphorylation of histone H2AX in the vicinity of DSBs, creating foci in the nucleus whose enumeration can serve as a radiation biodosimeter. Here, we investigated γH2AX and DNA repair foci in peripheral blood lymphocytes of Göttingen minipigs that experienced acute partial body irradiation (PBI) with 49 Gy (± 6%) Co-60 γ-rays of the upper lumbar region. Blood samples taken 4, 24 and 168 hours post PBI were subjected to γ-H2AX, 53BP1 and MRE11 focus enumeration. Peripheral blood lymphocytes (PBL) of 49 Gy partial body irradiated minipigs were found to display 1-8 DNA damage foci/cell. These PBL values significantly deceed the high foci numbers observed in keratinocyte nuclei of the directly γ-irradiated minipig skin regions, indicating a limited resident time of PBL in the exposed tissue volume. Nonetheless, PBL samples obtained 4 h post IR in average contained 2.2% of cells displaying a pan-γH2AX signal, suggesting that these received a higher IR dose. Moreover, dispersion analysis indicated partial body irradiation for all 13 minipigs at 4 h post IR. While dose reconstruction using γH2AX DNA repair foci in lymphocytes after in vivo PBI represents a challenge, the DNA damage focus assay may serve as a rapid, first line indicator of radiation exposure. The occurrence of PBLs with pan-γH2AX staining and of cells with relatively high foci numbers that skew a Poisson distribution may be taken as indicator of acute high dose partial body irradiation, particularly when samples are available early after IR

  12. Multifluid Modeling of the Partially Ionized Chromosphere with Effects of Impact Ionization, Radiative Recombination and Charge Exchange

    NASA Astrophysics Data System (ADS)

    Maneva, Y. G.; Poedts, D. S.; Alvarez Laguna, A.; Lani, A.

    2015-12-01

    driver to simulate the propagation of MHD waves in the partially ionized gravitationally stratified system.

  13. The plasmoid instability during magnetic reconnection in partially ionized chromospheric plasmas

    NASA Astrophysics Data System (ADS)

    Murphy, Nicholas A.; Lukin, Vyacheslav S.

    2015-04-01

    Magnetic reconnection is a ubiquitous process in the partially ionized solar chromosphere. Recent 2D simulations have shown that the plasmoid instability onsets during partially ionized reconnection [1-3]. We use the plasma-neutral module of the HiFi framework to simulate the nonlinear evolution of the plasmoid instability during symmetric and asymmetric reconnection. These simulations model the plasma and neutrals as separate fluids and include ionization, recombination, the Hall effect, charge exchange, thermal conduction, and optically thin radiative cooling. As in previous simulations [1,2], an enhancement of plasma density in the current sheet and plasmoids leads to recombination being an important loss term in the plasma continuity equation. The Hall term leads to the development of significant out-of-plane magnetic fields in the current sheet region, but we do not observe shortening of the current sheet or acceleration of the reconnection rate as a result. Secondary merging of magnetic islands is modified by inflow asymmetry and often results in an enhancement of the core field in the resulting islands. [1] Leake et al. 2012, ApJ, 760, 109 [2] Leake et al. 2013, PhPl, 20, 062102 [3] Ni et al. 2015, ApJ, 799, 79

  14. Dynamics of Coronal Rain and Descending Plasma Blobs in Solar Prominences. II. Partially Ionized Case

    NASA Astrophysics Data System (ADS)

    Oliver, R.; Soler, R.; Terradas, J.; Zaqarashvili, T. V.

    2016-02-01

    Coronal rain clumps and prominence knots are dense condensations with chromospheric to transition region temperatures that fall down in the much hotter corona. Their typical speeds are in the range 30-150 km s-1 and of the order of 10-30 km s-1, respectively, i.e., they are considerably smaller than free-fall velocities. These cold blobs contain a mixture of ionized and neutral material that must be dynamically coupled in order to fall together, as observed. We investigate this coupling by means of hydrodynamic simulations in which the coupling arises from the friction between ions and neutrals. The numerical simulations presented here are an extension of those of Oliver et al. to the partially ionized case. We find that, although the relative drift speed between the two species is smaller than 1 m s-1 at the blob center, it is sufficient to produce the forces required to strongly couple charged particles and neutrals. The ionization degree has no discernible effect on the main results of our previous work for a fully ionized plasma: the condensation has an initial acceleration phase followed by a period with roughly constant velocity, and, in addition, the maximum descending speed is clearly correlated with the ratio of initial blob to environment density.

  15. Advanced carbon-based material C60 modification using partially ionized cluster and energetic beams

    NASA Astrophysics Data System (ADS)

    Yuancheng, Du; Zhongmin, Ren; Zhifeng, Ying; Ning, Xu; Fuming, Li

    1997-06-01

    Two processes have been undertaken using Partially ionized cluster deposition (PICBD) and energetic ion bombardment beams deposition (IBD) respectively. C60 films deposited by PICBD at V=0 and 65 V, which result in highly textured close-packed structure in orientation (110) and being more polycrystalline respectively, the resistance of C60 films to oxygen diffusion contamination will be improved. In the case of PICBD, the ionized C60 soccer-balls molecules in the evaporation beams will be fragmented in collision with the substrate under the elevated accelerating fields Va. As a new synthetic IBD processing, two low energy (400 and 1000 eV) nitrogen ion beams have been used to bombard C60 films to synthesize the carbon nitride films.

  16. Equation of state of dense neon and krypton plasmas in the partial ionization regime

    SciTech Connect

    Chen, Q. F. Zheng, J.; Gu, Y. J.; Li, Z. G.

    2015-12-15

    The compression behaviors of dense neon and krypton plasmas over a wide pressure-temperature range are investigated by self-consistent fluid variational theory. The ionization degree and equation of state of dense neon and krypton are calculated in the density-temperature range of 0.01–10 g/cm{sup 3} and 4–50 kK. A region of thermodynamic instability is found which is related to the plasma phase transition. The calculated shock adiabat and principal Hugoniot of liquid krypton are in good agreement with available experimental data. The predicted results of shock-compressed liquid neon are presented, which provide a guide for dynamical experiments or numerical first-principle calculations aimed at studying the compression properties of liquid neon in the partial ionization regime.

  17. The collisional drift mode in a partially ionized plasma. [in the F region

    NASA Technical Reports Server (NTRS)

    Hudson, M. K.; Kennel, C. F.

    1974-01-01

    The structure of the drift instability was examined in several density regimes. Let sub e be the total electron mean free path, k sub z the wave-vector component along the magnetic field, and the ratio of perpendicular ion diffusion to parallel electron streaming rates. At low densities (k sub z lambda 1) the drift mode is isothermal and should be treated kineticly. In the finite heat conduction regime square root of m/M k sub z Lambda sub 1) the drift instability threshold is reduced at low densities and increased at high densities as compared to the isothermal threshold. Finally, in the energy transfer limit (k sub z kambda sub e square root of m/M) the drift instability behaves adiabatically in a fully ionized plasma and isothermally in a partially ionized plasma for an ion-neutral to Coulomb collision frequency ratio.

  18. Measuring partial body potassium in the arm versus total body potassium.

    PubMed

    Wielopolski, L; Ramirez, L M; Gallagher, D; Sarkar, S R; Zhu, F; Kaysen, G A; Levin, N W; Heymsfield, S B; Wang, Z M

    2006-09-01

    Skeletal muscle (SM), the body's main structural support, has been implicated in metabolic, physiological, and disease processes in humans. Despite being the largest tissue in the human body, its assessment remains difficult and indirect. However, being metabolically active it contains over 50% of the total body potassium (TBK) pool. We present our preliminary results from a new system for measuring partial body K (PBK) that presently are limited to the arm yet provide a direct and specific measure of the SM. This uniquely specific quantification of the SM mass in the arm, which is shielded from the body during measurement, allows us to simplify the assumptions used in deriving the total SM, thereby possibly improving the modeling of the human body compartments. Preliminary results show that PBK measurements are consistent with those from the TBK previously obtained from the same subjects, thus offering a simpler alternative to computed tomography and magnetic resonance imaging used for the same purposes. The PBK system, which can be set up in a physician's office or bedside in a hospital, is completely passive, safe, and inexpensive; it can be used on immobilized patients, children, pregnant women, or other at-risk populations. PMID:16741259

  19. Finite-temperature exchange-correlation theory for dense, partially ionized matter

    SciTech Connect

    Ritchie, A B

    2006-12-21

    The importance of exchange-correlation in dense, partially-ionized matter at elevated temperatures is demonstrated using ab initio theoretical methods. Good agreement with the Kohn-Sham exchange model, as extended to finite temperatures by Gupta and Rajagopal, is obtained for the Be Hugoniot at maximum compression. Exchange correlation is achieved by calculating the quantum average of the electron-electron interaction using the spectral solution of the time-dependent Schrodinger equation, which is a superposition of eigenfunctions. The quantum average of the electron-electron interaction has strong temporal fluctuations about a stationary time average. The eigenfunctions calculated in the temporally fluctuating potential are sensibly stationary.

  20. Spatially Resolved Thermodynamics of the Partially Ionized Exciton Gas in GaAs.

    PubMed

    Bieker, S; Henn, T; Kiessling, T; Ossau, W; Molenkamp, L W

    2015-06-01

    We report on the observation of macroscopic free exciton photoluminescence (PL) rings that appear in spatially resolved PL images obtained on a high purity GaAs sample. We demonstrate that a spatial temperature gradient in the photocarrier system, which is due to nonresonant optical excitation, locally modifies the population balance between free excitons and the uncorrelated electron-hole plasma described by the Saha equation and accounts for the experimentally observed nontrivial PL profiles. The exciton ring formation is a particularly instructive manifestation of the spatially dependent thermodynamics of a partially ionized exciton gas in a bulk semiconductor. PMID:26196644

  1. Spatially Resolved Thermodynamics of the Partially Ionized Exciton Gas in GaAs

    NASA Astrophysics Data System (ADS)

    Bieker, S.; Henn, T.; Kiessling, T.; Ossau, W.; Molenkamp, L. W.

    2015-06-01

    We report on the observation of macroscopic free exciton photoluminescence (PL) rings that appear in spatially resolved PL images obtained on a high purity GaAs sample. We demonstrate that a spatial temperature gradient in the photocarrier system, which is due to nonresonant optical excitation, locally modifies the population balance between free excitons and the uncorrelated electron-hole plasma described by the Saha equation and accounts for the experimentally observed nontrivial PL profiles. The exciton ring formation is a particularly instructive manifestation of the spatially dependent thermodynamics of a partially ionized exciton gas in a bulk semiconductor.

  2. Effects of viscosity in a partially ionized channel flow with thermionic emission

    SciTech Connect

    Mikellides, Ioannis G.

    2009-01-15

    The flow of the partially ionized gas inside thermionic hollow cathodes spans a diverse range of theoretical disciplines in plasma physics and fluid mechanics. Understanding and predicting the evolution of such flows has many practical implications because hollow cathodes are critical components of electric propulsion systems used onboard scientific and commercial spacecraft presently in space or in the mission planning stages. As space missions become more demanding of the propulsion system in terms of throughput, understanding and predicting failure mechanisms of the system becomes imperative. Two-dimensional numerical simulations of the partially ionized gas generated by a thermionic hollow cathode have been performed to quantify the effects of viscosity inside the cylindrical channel of the device. A comparison of the inviscid and fully viscous flow fields shows that viscosity has a significant impact on the atomic species and a lesser effect on the ions. The internal pressure is determined to be more than 40% higher compared to the inviscid solution and the Reynolds number for the flow of atoms is found to be less than 20 inside the channel. Although the Mach number is computed to be <0.1 for approximately 95% of the channel, the solution for the velocity flow field begins to deviate from the Poiseuille (parabolic) solution at about 50% of the channel due mainly to collisional drag with ions.

  3. An equation of state for partially ionized plasmas: The Coulomb contribution to the free energy

    SciTech Connect

    Kilcrease, D. P.; Colgan, J.; Hakel, P.; Fontes, C. J.; Sherrill, M. E.

    2015-06-20

    We have previously developed an equation of state (EOS) model called ChemEOS (Hakel and Kilcrease, Atomic Processes in Plasmas, Eds., J. Cohen et al., AIP, 2004) for a plasma of interacting ions, atoms and electrons. It is based on a chemical picture of the plasma and is derived from an expression for the Helmholtz free energy of the interacting species. All other equilibrium thermodynamic quantities are then obtained by minimizing this free energy subject to constraints, thus leading to a thermodynamically consistent EOS. The contribution to this free energy from the Coulomb interactions among the particles is treated using the method of Chabrier and Potekhin (Phys. Rev. E 58, 4941 (1998)) which we have adapted for partially ionized plasmas. This treatment is further examined and is found to give rise to unphysical behavior for various elements at certain values of the density and temperature where the Coulomb coupling begins to become significant and the atoms are partially ionized. We examine the source of this unphysical behavior and suggest corrections that produce acceptable results. The sensitivity of the thermodynamic properties and frequency-dependent opacity of iron is examined with and without these corrections. Lastly, the corrected EOS is used to determine the fractional ion populations and level populations for a new generation of OPLIB low-Z opacity tables currently being prepared at Los Alamos National Laboratory with the ATOMIC code.

  4. Cluster virial expansion for the equation of state of partially ionized hydrogen plasma

    SciTech Connect

    Omarbakiyeva, Y. A.; Fortmann, C.; Ramazanov, T. S.; Roepke, G.

    2010-08-15

    We study the contribution of electron-atom interaction to the equation of state for partially ionized hydrogen plasma using the cluster-virial expansion. We use the Beth-Uhlenbeck approach to calculate the second virial coefficient for the electron-atom (bound cluster) pair from the corresponding scattering phase shifts and binding energies. Experimental scattering cross-sections as well as phase shifts calculated on the basis of different pseudopotential models are used as an input for the Beth-Uhlenbeck formula. By including Pauli blocking and screening in the phase shift calculation, we generalize the cluster-virial expansion in order to cover also near solid density plasmas. We present results for the electron-atom contribution to the virial expansion and the corresponding equation of state, i.e. pressure, composition, and chemical potential as a function of density and temperature. These results are compared with semiempirical approaches to the thermodynamics of partially ionized plasmas. Avoiding any ill-founded input quantities, the Beth-Uhlenbeck second virial coefficient for the electron-atom interaction represents a benchmark for other, semiempirical approaches.

  5. An equation of state for partially ionized plasmas: The Coulomb contribution to the free energy

    NASA Astrophysics Data System (ADS)

    Kilcrease, D. P.; Colgan, J.; Hakel, P.; Fontes, C. J.; Sherrill, M. E.

    2015-09-01

    We have previously developed an equation of state (EOS) model called ChemEOS (Hakel and Kilcrease, Atomic Processes in Plasmas, Eds., J. Cohen et al., AIP, 2004) for a plasma of interacting ions, atoms and electrons. It is based on a chemical picture of the plasma and is derived from an expression for the Helmholtz free energy of the interacting species. All other equilibrium thermodynamic quantities are then obtained by minimizing this free energy subject to constraints, thus leading to a thermodynamically consistent EOS. The contribution to this free energy from the Coulomb interactions among the particles is treated using the method of Chabrier and Potekhin (Phys. Rev. E 58, 4941 (1998)) which we have adapted for partially ionized plasmas. This treatment is further examined and is found to give rise to unphysical behavior for various elements at certain values of the density and temperature where the Coulomb coupling begins to become significant and the atoms are partially ionized. We examine the source of this unphysical behavior and suggest corrections that produce acceptable results. The sensitivity of the thermodynamic properties and frequency-dependent opacity of iron is examined with and without these corrections. The corrected EOS is used to determine the fractional ion populations and level populations for a new generation of OPLIB low-Z opacity tables currently being prepared at Los Alamos National Laboratory with the ATOMIC code.

  6. Cluster virial expansion for the equation of state of partially ionized hydrogen plasma.

    PubMed

    Omarbakiyeva, Y A; Fortmann, C; Ramazanov, T S; Röpke, G

    2010-08-01

    We study the contribution of electron-atom interaction to the equation of state for partially ionized hydrogen plasma using the cluster-virial expansion. We use the Beth-Uhlenbeck approach to calculate the second virial coefficient for the electron-atom (bound cluster) pair from the corresponding scattering phase shifts and binding energies. Experimental scattering cross-sections as well as phase shifts calculated on the basis of different pseudopotential models are used as an input for the Beth-Uhlenbeck formula. By including Pauli blocking and screening in the phase shift calculation, we generalize the cluster-virial expansion in order to cover also near solid density plasmas. We present results for the electron-atom contribution to the virial expansion and the corresponding equation of state, i.e. pressure, composition, and chemical potential as a function of density and temperature. These results are compared with semiempirical approaches to the thermodynamics of partially ionized plasmas. Avoiding any ill-founded input quantities, the Beth-Uhlenbeck second virial coefficient for the electron-atom interaction represents a benchmark for other, semiempirical approaches. PMID:20866926

  7. An equation of state for partially ionized plasmas: The Coulomb contribution to the free energy

    DOE PAGESBeta

    Kilcrease, D. P.; Colgan, J.; Hakel, P.; Fontes, C. J.; Sherrill, M. E.

    2015-06-20

    We have previously developed an equation of state (EOS) model called ChemEOS (Hakel and Kilcrease, Atomic Processes in Plasmas, Eds., J. Cohen et al., AIP, 2004) for a plasma of interacting ions, atoms and electrons. It is based on a chemical picture of the plasma and is derived from an expression for the Helmholtz free energy of the interacting species. All other equilibrium thermodynamic quantities are then obtained by minimizing this free energy subject to constraints, thus leading to a thermodynamically consistent EOS. The contribution to this free energy from the Coulomb interactions among the particles is treated using themore » method of Chabrier and Potekhin (Phys. Rev. E 58, 4941 (1998)) which we have adapted for partially ionized plasmas. This treatment is further examined and is found to give rise to unphysical behavior for various elements at certain values of the density and temperature where the Coulomb coupling begins to become significant and the atoms are partially ionized. We examine the source of this unphysical behavior and suggest corrections that produce acceptable results. The sensitivity of the thermodynamic properties and frequency-dependent opacity of iron is examined with and without these corrections. Lastly, the corrected EOS is used to determine the fractional ion populations and level populations for a new generation of OPLIB low-Z opacity tables currently being prepared at Los Alamos National Laboratory with the ATOMIC code.« less

  8. Partial cross sections of doubly excited helium below the ionization threshold I{sub 7}

    SciTech Connect

    Jiang, Y.H.; Puettner, R.; Poiguine, M.; Kaindl, G.; Hentges, R.; Viefhaus, J.; Becker, U.; Rost, J.M.

    2004-04-01

    Partial photoionization cross sections (PCSs), {sigma}{sub n}, leading to final ionic states of helium, He{sup +}(n), were measured at BESSY II in the region of doubly excited helium up to the ionization threshold I{sub 7} of He{sup +}. The experiments were performed with a time-of-flight (TOF) electron spectrometer and high photon resolution, {delta}E congruent with 6 meV. The results of these measurements are a most critical assessment of the decay dynamics of double-excitation resonances and agree well with those of recent eigenchannel R-matrix calculations. They also confirm the propensity rules set up for the autoionization of doubly excitated states. The mirroring behavior in the PCSs predicted recently by Liu and Starace is only partially observed. By discussing the formulas given by these authors in a more general context, the specific behavior of the PCSs of helium with respect to mirroring can be understood. The mirroring compensation properties between the 'fractional partial cross sections' {gamma}{sub P}={sigma}{sub P}/{sigma}{sub T} and {gamma}{sub Q}={sigma}{sub Q}/{sigma}{sub T}, with {sigma}{sub T}={sigma}{sub P}+{sigma}{sub Q}, are introduced and discussed.

  9. Heating of the Partially Ionized Solar Chromosphere by Waves in Magnetic Structures

    NASA Astrophysics Data System (ADS)

    Shelyag, S.; Khomenko, E.; de Vicente, A.; Przybylski, D.

    2016-03-01

    In this paper, we show a “proof of concept” of the heating mechanism of the solar chromosphere due to wave dissipation caused by the effects of partial ionization. Numerical modeling of non-linear wave propagation in a magnetic flux tube, embedded in the solar atmosphere, is performed by solving a system of single-fluid quasi-MHD equations, which take into account the ambipolar term from the generalized Ohm’s law. It is shown that perturbations caused by magnetic waves can be effectively dissipated due to ambipolar diffusion. The energy input by this mechanism is continuous and shown to be more efficient than dissipation of static currents, ultimately leading to chromospheric temperature increase in magnetic structures.

  10. Study on the electromagnetic waves propagation characteristics in partially ionized plasma slabs

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Bin; Li, Bo-Wen; Nie, Qiu-Yue; Wang, Xiao-Gang; Kong, Fan-Rong

    2016-05-01

    Propagation characteristics of electromagnetic (EM) waves in partially ionized plasma slabs are studied in this paper. Such features are significant to applications in plasma antennas, blackout of re-entry flying vehicles, wave energy injection to plasmas, and etc. We in this paper developed a theoretical model of EM wave propagation perpendicular to a plasma slab with a one-dimensional density inhomogeneity along propagation direction to investigate essential characteristics of EM wave propagation in nonuniform plasmas. Particularly, the EM wave propagation in sub-wavelength plasma slabs, where the geometric optics approximation fails, is studied and in comparison with thicker slabs where the geometric optics approximation applies. The influences of both plasma and collisional frequencies, as well as the width of the plasma slab, on the EM wave propagation characteristics are discussed. The results can help the further understanding of propagation behaviours of EM waves in nonuniform plasma, and applications of the interactions between EM waves and plasmas.

  11. Shear flow instability in a partially-ionized plasma sheath around a fast-moving vehicle

    SciTech Connect

    Sotnikov, V. I.; Mudaliar, S.; Genoni, T. C.; Rose, D. V.; Oliver, B. V.; Mehlhorn, T. A.

    2011-06-15

    The stability of ion acoustic waves in a sheared-flow, partially-ionized compressible plasma sheath around a fast-moving vehicle in the upper atmosphere, is described and evaluated for different flow profiles. In a compressible plasma with shear flow, instability occurs for any velocity profile, not just for profiles with an inflection point. A second-order differential equation for the electrostatic potential of excited ion acoustic waves in the presence of electron and ion collisions with neutrals is derived and solved numerically using a shooting method with boundary conditions appropriate for a finite thickness sheath in contact with the vehicle. We consider three different velocity flow profiles and find that in all cases that neutral collisions can completely suppress the instability.

  12. Injection to Rapid Diffusive Shock Acceleration at Perpendicular Shocks in Partially Ionized Plasmas

    NASA Astrophysics Data System (ADS)

    Ohira, Yutaka

    2016-08-01

    We present a three-dimensional hybrid simulation of a collisionless perpendicular shock in a partially ionized plasma for the first time. In this simulation, the shock velocity and upstream ionization fraction are v sh ≈ 1333 km s‑1 and f i ˜ 0.5, which are typical values for isolated young supernova remnants (SNRs) in the interstellar medium. We confirm previous two-dimensional simulation results showing that downstream hydrogen atoms leak into the upstream region and are accelerated by the pickup process in the upstream region, and large magnetic field fluctuations are generated both in the upstream and downstream regions. In addition, we find that the magnetic field fluctuations have three-dimensional structures and the leaking hydrogen atoms are injected into the diffusive shock acceleration (DSA) at the perpendicular shock after the pickup process. The observed DSA can be interpreted as shock drift acceleration with scattering. In this simulation, particles are accelerated to v ˜ 100 v sh ˜ 0.3 c within ˜100 gyroperiods. The acceleration timescale is faster than that of DSA in parallel shocks. Our simulation results suggest that SNRs can accelerate cosmic rays to 1015.5 eV (the knee) during the Sedov phase.

  13. Partial ionization in dense plasmas: comparisons among average-atom density functional models.

    PubMed

    Murillo, Michael S; Weisheit, Jon; Hansen, Stephanie B; Dharma-wardana, M W C

    2013-06-01

    Nuclei interacting with electrons in dense plasmas acquire electronic bound states, modify continuum states, generate resonances and hopping electron states, and generate short-range ionic order. The mean ionization state (MIS), i.e, the mean charge Z of an average ion in such plasmas, is a valuable concept: Pseudopotentials, pair-distribution functions, equations of state, transport properties, energy-relaxation rates, opacity, radiative processes, etc., can all be formulated using the MIS of the plasma more concisely than with an all-electron description. However, the MIS does not have a unique definition and is used and defined differently in different statistical models of plasmas. Here, using the MIS formulations of several average-atom models based on density functional theory, we compare numerical results for Be, Al, and Cu plasmas for conditions inclusive of incomplete atomic ionization and partial electron degeneracy. By contrasting modern orbital-based models with orbital-free Thomas-Fermi models, we quantify the effects of shell structure, continuum resonances, the role of exchange and correlation, and the effects of different choices of the fundamental cell and boundary conditions. Finally, the role of the MIS in plasma applications is illustrated in the context of x-ray Thomson scattering in warm dense matter. PMID:23848795

  14. Injection to Rapid Diffusive Shock Acceleration at Perpendicular Shocks in Partially Ionized Plasmas

    NASA Astrophysics Data System (ADS)

    Ohira, Yutaka

    2016-08-01

    We present a three-dimensional hybrid simulation of a collisionless perpendicular shock in a partially ionized plasma for the first time. In this simulation, the shock velocity and upstream ionization fraction are v sh ≈ 1333 km s‑1 and f i ∼ 0.5, which are typical values for isolated young supernova remnants (SNRs) in the interstellar medium. We confirm previous two-dimensional simulation results showing that downstream hydrogen atoms leak into the upstream region and are accelerated by the pickup process in the upstream region, and large magnetic field fluctuations are generated both in the upstream and downstream regions. In addition, we find that the magnetic field fluctuations have three-dimensional structures and the leaking hydrogen atoms are injected into the diffusive shock acceleration (DSA) at the perpendicular shock after the pickup process. The observed DSA can be interpreted as shock drift acceleration with scattering. In this simulation, particles are accelerated to v ∼ 100 v sh ∼ 0.3 c within ∼100 gyroperiods. The acceleration timescale is faster than that of DSA in parallel shocks. Our simulation results suggest that SNRs can accelerate cosmic rays to 1015.5 eV (the knee) during the Sedov phase.

  15. Feasibility study of in vivo partial body potassium determination in the human body using gamma-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Ramirez, Lisa Marie

    This work investigates partial body potassium determination in the human body using gamma-ray spectroscopy. Potassium is an essential element in the human body that controls many of the enzyme systems and intra- and extra-cellular water flow. Potassium is symptomatic to several disease cases and has gender and ethnic variability. This work assesses the feasibility to measure partial body potassium in three specific regions: brain, arm, and leg, that are of interest to multiple sclerosis, chronic renal failure, and spinal cord injury, respectively. Three detector systems were constructed and their capabilities assessed. System characterization and analytical procedure for potassium evaluation and determination are presented together with experimental and initial clinical results. The results indicate that partial body potassium measurement is viable, statistically reproducible, and has potential clinical significance.

  16. SLAC three-body partial wave analysis system

    SciTech Connect

    Aston, D.; Lasinski, T.A.; Sinervo, P.K.

    1985-10-01

    We present a heuristic description of the SLAC-LBL three-meson partial wave model, and describe how we have implemented it at SLAC. The discussion details the assumptions of the model and the analysis, and emphasizes the methods we have used to prepare and fit the data. 28 refs., 12 figs., 1 tab.

  17. Impact of the Partial Ionization in the solar atmosphere using 2.5D Radiative MHD Simulations

    NASA Astrophysics Data System (ADS)

    Martinez-Sykora, Juan; De Pontieu, Bart; Hansteen, Viggo; Carlsson, Mats

    The chromosphere/transition region constitute the interface between the solar surface and the corona and modulate the flow of mass and energy into the upper atmosphere. IRIS was launched in 2013 to study the chromosphere and transition region. The complexity of the chromosphere is due to various regime changes that take place across it, like: Hydrogen goes from predominantly neutral to predominantly ionized; the plasma behavior changes from collisional to collision-less; it goes from gas-pressure dominated to magnetically driven, etc. Consequently, the interpretation of chromospheric observations in general and those from IRIS, in particular, is a challenging task. It is thus crucial to combine IRIS observations with advanced radiative-MHD numerical modeling. Because the photosphere, chromosphere and transition region are partially ionized, the interaction between ionized and neutral particles has important consequences on the magneto-thermodynamics of these regions. We implemented the effects of partial ionization using generalized Ohm's law in the Bifrost code (Gudiksen et al. 2011) which includes full MHD equations with non-grey and non-LTE radiative transfer and thermal conduction along magnetic field lines. I will describe the importance and impact of taking into account partial ionization effects in the modeled radiative-MHD atmosphere, such as chromospheric heating, photospheric magnetic field diffused into the upper-chromosphere which expands into the upper atmosphere filling the corona with mass, magnetic flux, energy and current, etc.

  18. Two-fluid modeling of magnetosonic wave propagation in the partially ionized solar chromosphere

    NASA Astrophysics Data System (ADS)

    Maneva, Yana; Alvarez Laguna, Alejandro; Lani, Andrea; Poedts, Stefaan

    2016-04-01

    We perform 2D two-fluid simulations to study the effects of ion-neutral interactions on the propagation of magnetosonic waves in the partially ionized solar chromosphere, where the number density of neutrals significantly exceeds the number density of protons at low heights. Thus modeling the neutral-ion interactions and studying the effect of neutrals on the ambient plasma properties becomes important for better understanding the observed emission lines and the propagation of disturbances from the photosphere to the transition region and the corona. The role of charged particles (electrons and ions) is combined within resistive MHD approach with Coulomb collisions and anisotropic heat flux determined by Braginskii's transport coefficients. The electromagnetic fields are evolved according to the full Maxwell equations, allowing for propagation of higher frequency waves neglected by the standard MHD approximation. Separate mass, momentum and energy conservation equations are considered for the neutrals and the interaction between the different fluids is determined by the chemical reactions, such as impact ionization, radiative recombination and charge exchange, provided as additional source terms. To initialize the system we consider an ideal gas equation of state with equal initial temperatures for the electrons, ions and the neutrals and different density profiles. The initial temperature and density profiles are height-dependent and follow VAL C atmospheric model for the solar chromosphere. We have searched for a chemical and collisional equilibrium between the ions and the neutrals to minimize any unphysical outflows and artificial heating induced by initial pressure imbalances. Including different magnetic field profiles brings new source of plasma heating through Ohmic dissipation. The excitation and propagation of the magnetosonic waves depends on the type of the external velocity driver. As the waves propagate through the gravitationally stratified media

  19. Partially Ionized Plasma Three-Fluid Modeling of Magnetic Reconnection in the Sun Chromosphere

    NASA Astrophysics Data System (ADS)

    Alvarez Laguna, A.; Lani, A.; Mansour, N. N.; Kosovichev, A. G.; Poedts, D. S.

    2015-12-01

    Magnetic reconnection is present in most of the unsteady and eruptive phenomena in the Sun atmosphere, including Coronal Mass Ejections (CMEs) and solar flares. Also, it occurs in the chromosphere, bringing about chromospheric jets and spicules and being considered a likely mechanism to play an important role in heating up the corona. In this work, we present a computational model that simulates magnetic reconnection in the Sun chromosphere using a three-fluid model (electrons + ions + neutrals). The model treats separately ions, electrons and neutrals, considering mass, momentum and energy conservation for each fluid. The fluids interact among each other by means of collisions and chemical reactions. The charged particles heat fluxes are anisotropic with the magnetic field, following Braginskii's description. This model also considers non-equilibrium partial ionization effects including electron impact ionization, radiative recombination reactions and charge exchange. The electromagnetic field evolution is represented by the full Maxwell's equations, allowing for high frequency waves disregarded by the MHD approximation. Previous two-fluid simulations showed that the dynamics of ions and neutrals are decoupled during the reconnection process when the width of the current sheet becomes comparable to the ion scales. Also, the effect of the chemical non-equilibrium in the reconnection region plays a crucial role, yielding faster reconnection rates. We extended these simulations with a three-fluid model that considers separately the dynamics of electrons. This new model provides a better description of the complex dynamics taking place during the reconnection, both in Sweet-Parker reconnections and during the tearing instability. The results are compared with the two-fluid simulations.

  20. TWO-DIMENSIONAL RADIATIVE MAGNETOHYDRODYNAMIC SIMULATIONS OF THE IMPORTANCE OF PARTIAL IONIZATION IN THE CHROMOSPHERE

    SciTech Connect

    Martinez-Sykora, Juan; De Pontieu, Bart; Hansteen, Viggo

    2012-07-10

    The bulk of the solar chromosphere is weakly ionized and interactions between ionized particles and neutral particles likely have significant consequences for the thermodynamics of the chromospheric plasma. We investigate the importance of introducing neutral particles into the MHD equations using numerical 2.5D radiative MHD simulations obtained with the Bifrost code. The models span the solar atmosphere from the upper layers of the convection zone to the low corona, and solve the full MHD equations with non-gray and non-LTE radiative transfer, and thermal conduction along the magnetic field. The effects of partial ionization are implemented using the generalized Ohm's law, i.e., we consider the effects of the Hall term and ambipolar diffusion in the induction equation. The approximations required in going from three fluids to the generalized Ohm's law are tested in our simulations. The Ohmic diffusion, Hall term, and ambipolar diffusion show strong variations in the chromosphere. These strong variations of the various magnetic diffusivities are absent or significantly underestimated when, as has been common for these types of studies, using the semi-empirical VAL-C model as a basis for estimates. In addition, we find that differences in estimating the magnitude of ambipolar diffusion arise depending on which method is used to calculate the ion-neutral collision frequency. These differences cause uncertainties in the different magnetic diffusivity terms. In the chromosphere, we find that the ambipolar diffusion is of the same order of magnitude or even larger than the numerical diffusion used to stabilize our code. As a consequence, ambipolar diffusion produces a strong impact on the modeled atmosphere. Perhaps more importantly, it suggests that at least in the chromospheric domain, self-consistent simulations of the solar atmosphere driven by magnetoconvection can accurately describe the impact of the dominant form of resistivity, i.e., ambipolar diffusion. This

  1. Radiative condensation instability in partially ionized dusty plasma with polarization force

    NASA Astrophysics Data System (ADS)

    Sharma, Prerana; Jain, Shweta

    2016-01-01

    This paper studies the effect of polarization force on the radiative condensation (RC) instability of a partially ionized dusty medium both in the presence and absence of self-gravitation. The temperature and density dependent heat loss function is considered in the process of heating and radiative cooling. The linear-perturbation analysis is used to derive general dispersion relation and criteria for both the Jeans and RC instability. The condition of Jeans instability is modified due to the RC, polarization force, magnetic field and dust thermal speed, whereas in the case of RC instability the instability criterion is modified due to the presence of dust thermal speed, magnetic field and polarization force. The effects of various parameters have been numerically estimated on RC instability. It is clear from figure that the presence of polarization parameter and density dependent heat-loss function destabilize the system while the presence of temperature dependent heat-loss function, dust neutral collision frequency and ratio of neutral dust density stabilize the system. These findings are relevant for many areas of space and laboratory plasma research prime examples being the formation of dense molecular clouds in interstellar and intergalactic medium, condensations in planetary nebulae and in laboratory plasmas like tokamak edge plasma.

  2. Inactivation of human immunodeficiency virus (HIV) by ionizing radiation in body fluids and serological evidence

    SciTech Connect

    Bigbee, P.D.; Sarin, P.S.; Humphreys, J.C.; Eubanks, W.G.; Sun, D.; Hocken, D.G.; Thornton, A.; Adams, D.E.; Simic, M.G. )

    1989-11-01

    A method to use ionizing radiation to inactivate HIV (Human Immunodeficiency Virus) in human body fluids was studied in an effort to reduce the risk of accidental infection to forensic science laboratory workers. Experiments conducted indicate that an X-ray absorbed dose of 25 krad was required to completely inactivate HIV. This does not alter forensically important constituents such as enzymes and proteins in body fluids. This method of inactivation of HIV cannot be used on body fluids which will be subjected to deoxyribonucleic acid (DNA) typing.

  3. Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere

    NASA Astrophysics Data System (ADS)

    Singh, K. A. P.; Shibata, K.; Nishizuka, N.; Isobe, H.

    2011-11-01

    The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfvén speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona (λi > δSP), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.

  4. Grain growth in thin Al films during deposition from partially ionized vapor

    NASA Astrophysics Data System (ADS)

    Gusev, I. V.; Mokhniuk, A. A.

    2016-07-01

    Grain growth in thin Al films during deposition from partially ionized vapor flux with simultaneous self-ion bombardment was studied in this work. The films were deposited at constant ion energy of 940 eV and total specific power of 0.4 W/cm2 while the deposition time t of 6 s to 246 s and the resulting substrate temperature (Ts/Tm of 0.35-0.96) were varied. Thin continuous Al films exhibited normal grain growth through the entire experimental range of deposition time without limitation of grain growth by the film thickness effect. Three kinetic stages of the grain growth were observed within 100 s of deposition time: the first one exhibits very slow grain growth, accelerated grain growth occurs in the second stage and then it rapidly changes to a retardation and stagnation mode in the third stage. Large average grain sizes Dg up to 11.3 μm at film thickness of 1.4 μm and integral grain growth rates up to 0.16 μm/s were observed in this study. The experimental results were evaluated against various mechanisms of inhibition of grain growth. An estimate of the effective activation energy of the grain growth yields a value of 0.27 eV which is lower than that of the bulk Al and much higher than the activation energy of surface self-diffusion on (1 1 1)Al monocrystal. The power law Dg = (k t)0.5 gives good match with experimental results in the initial deposition phase preceding the grain growth retardation, while another model that is based on the grain size dependent pinning force adequately explains the entire grain size dependence on time. It is deemed both ion enhanced film/surface interaction and impurities on one side and thermal grooves on another side contribute to the rapid retardation of the grain grooves commencing the second growth stage.

  5. Chromospheric anemone jets and magnetic reconnection in partially ionized solar atmosphere

    SciTech Connect

    Singh, K. A. P.; Shibata, K.; Nishizuka, N.; Isobe, H.

    2011-11-15

    The solar optical telescope onboard Hinode with temporal resolution of less than 5 s and spatial resolution of 150 km has observed the lower solar atmosphere with an unprecedented detail. This has led to many important findings, one of them is the discovery of chromospheric anemone jets in the solar chromosphere. The chromospheric anemone jets are ubiquitous in solar chromosphere and statistical studies show that the typical length, life time and energy of the chromospheric anemone jets are much smaller than the coronal events (e.g., jets/flares/CMEs). Among various observational parameters, the apparent length and maximum velocity shows good correlation. The velocity of chromospheric anemone jets is comparable to the local Alfven speed in the lower solar chromosphere. Since the discovery of chromospheric anemone jets by Hinode, several evidences of magnetic reconnection in chromospheric anemone jets have been found and these observations are summarized in this paper. These observations clearly suggest that reconnection occurs quite rapidly as well as intermittently in the solar chromosphere. In the solar corona ({lambda}{sub i} > {delta}{sub SP}), anomalous resistivity arises due to various collisionless processes. Previous MHD simulations show that reconnection becomes fast as well as strongly time-dependent due to anomalous resistivity. Such processes would not arise in the solar chromosphere which is fully collisional and partially-ionized. So, it is unclear how the rapid and strongly time-dependent reconnection would occur in the solar chromosphere. It is quite likely that the Hall and ambipolar diffusion are present in the solar chromosphere and they could play an important role in driving such rapid, strongly time-dependent reconnection in the solar chromosphere.

  6. KINEMATICS IN PARTIALLY IONIZED MOLECULAR CLOUDS: IMPLICATIONS FOR THE TRANSITION TO COHERENCE

    SciTech Connect

    Bailey, Nicole D.; Caselli, Paola; Basu, Shantanu E-mail: caselli@mpe.mpg.de

    2015-01-10

    A previous paper by Bailey and Basu shows analysis of density and mass-to-flux ratio maps for simulations with either an ionization profile which takes into account photoionization (step-like profile) or a cosmic ray only ionization profile. We extend this study to analyze the effect of these ionization profiles on velocity structures, kinematics, and synthetic spectra. Clump regions are found to occur at the convergence of two flows with a low velocity region and velocity direction transition occurring at the junction. Models with evident substructure show that core formation occurs on the periphery of these velocity valleys. Analysis of synthetic spectra reveals the presence of large non-thermal components within low-density gas, especially for models with the step-like ionization profile. All cores show small, sub-thermal relative motions compared to background gas. Large deviations within this analysis are due to the line of sight intersecting low- and high-density regions across the velocity switch transition. Positive deviations correspond to a foreground core moving away from the observer while negative deviations correspond to a background core moving toward the observer. Comparison of velocities resulting from different ionization profiles suggest that high ionization fractions yield supersonic velocities, up to two times the sound speed, while regions with low ionization fractions tend to be subsonic or mildly supersonic. This suggests that the transition to coherence within cores could be a transition between high and low ionization fractions within the gas.

  7. Atom-atom inelastic collisions and three-body atomic recombination in weakly ionized argon plasmas

    NASA Technical Reports Server (NTRS)

    Braun, C. G.; Kunc, J. A.

    1989-01-01

    A stationary collisional-radiative model including both inelastic electron-atom and atom-atom collisions is used to examine nonequilibrium weakly ionized argon plasmas with atomic densities 10 to the 16th to 10 to the 20th/cu cm, temperatures below 6000 K, and with different degrees of radiation trapping. It is shown that three-body atomic recombination becomes important at high particle densities. Comparison is made between the present approach and Thomson's theory for atomic recombination.

  8. Exploring point-cloud features from partial body views for gender classification

    NASA Astrophysics Data System (ADS)

    Fouts, Aaron; McCoppin, Ryan; Rizki, Mateen; Tamburino, Louis; Mendoza-Schrock, Olga

    2012-06-01

    In this paper we extend a previous exploration of histogram features extracted from 3D point cloud images of human subjects for gender discrimination. Feature extraction used a collection of concentric cylinders to define volumes for counting 3D points. The histogram features are characterized by a rotational axis and a selected set of volumes derived from the concentric cylinders. The point cloud images are drawn from the CAESAR anthropometric database provided by the Air Force Research Laboratory (AFRL) Human Effectiveness Directorate and SAE International. This database contains approximately 4400 high resolution LIDAR whole body scans of carefully posed human subjects. Success from our previous investigation was based on extracting features from full body coverage which required integration of multiple camera images. With the full body coverage, the central vertical body axis and orientation are readily obtainable; however, this is not the case with a one camera view providing less than one half body coverage. Assuming that the subjects are upright, we need to determine or estimate the position of the vertical axis and the orientation of the body about this axis relative to the camera. In past experiments the vertical axis was located through the center of mass of torso points projected on the ground plane and the body orientation derived using principle component analysis. In a natural extension of our previous work to partial body views, the absence of rotational invariance about the cylindrical axis greatly increases the difficulty for gender classification. Even the problem of estimating the axis is no longer simple. We describe some simple feasibility experiments that use partial image histograms. Here, the cylindrical axis is assumed to be known. We also discuss experiments with full body images that explore the sensitivity of classification accuracy relative to displacements of the cylindrical axis. Our initial results provide the basis for further

  9. Treadmill Training with Partial Body-Weight Support in Children with Cerebral Palsy: A Systematic Review

    ERIC Educational Resources Information Center

    Mutlu, Akmer; Krosschell, Kristin; Spira, Deborah Gaebler

    2009-01-01

    OKAim: The aim of this systematic review was to examine the literature on the effects of partial body-weight support treadmill training (PBWSTT) in children with cerebral palsy (CP) on functional outcomes and attainment of ambulation. Method: We searched the relevant literature from 1950 to July 2007. We found eight studies on the use of PWSBTT on…

  10. Hyperspherical partial-wave theory applied to electron-hydrogen-atom ionization calculation for equal-energy-sharing kinematics

    SciTech Connect

    Das, J.N.; Paul, S.; Chakrabarti, K.

    2003-04-01

    Hyperspherical partial-wave theory has been applied here in a new way in the calculation of the triple differential cross sections for the ionization of hydrogen atoms by electron impact at low energies for various equal-energy-sharing kinematic conditions. The agreement of the cross section results with the recent absolute measurements of [J. Roeder, M. Baertschy, and I. Bray, Phys. Rev. A 45, 2951 (2002)] and with the latest theoretical results of the ECS and CCC calculations [J. Roeder, M. Baertschy, and I. Bray, Phys. Rev. A (to be published)] for different kinematic conditions at 17.6 eV is very encouraging. The other calculated results, for relatively higher energies, are also generally satisfactory, particularly for large {theta}{sub ab} geometries. In view of the present results, together with the fact that it is capable of describing unequal-energy-sharing kinematics [J. N. Das, J. Phys. B 35, 1165 (2002)], it may be said that the hyperspherical partial-wave theory is quite appropriate for the description of ionization events of electron-hydrogen-type systems. It is also clear that the present approach in the implementation of the hyperspherical partial-wave theory is very appropriate.

  11. Advanced carbon-based material C{sub 60} modification using partially ionized cluster and energetic beams

    SciTech Connect

    Du Yuancheng; Ren Zhongmin; Ning Zhifeng; Xu Ning; Li Fuming

    1997-06-20

    Two processes have been undertaken using Partially ionized cluster deposition (PICBD) and energetic ion bombardment beams deposition (IBD) respectively. C{sub 60} films deposited by PICBD at V=0 and 65 V, which result in highly textured close-packed structure in orientation (110) and being more polycrystalline respectively, the resistance of C{sub 60} films to oxygen diffusion contamination will be improved. In the case of PICBD, the ionized C{sub 60} soccer-balls molecules in the evaporation beams will be fragmented in collision with the substrate under the elevated accelerating fields Va. As a new synthetic IBD processing, two low energy (400 and 1000 eV) nitrogen ion beams have been used to bombard C{sub 60} films to synthesize the carbon nitride films.

  12. Assessment of simulated high-dose partial-body irradiation by PCC-R assay

    PubMed Central

    Romero, Ivonne; García, Omar; Lamadrid, Ana I.; Gregoire, Eric; González, Jorge E.; Morales, Wilfredo; Martin, Cécile; Barquinero, Joan-Francesc; Voisin, Philippe

    2013-01-01

    The estimation of the dose and the irradiated fraction of the body is important information in the primary medical response in case of a radiological accident. The PCC-R assay has been developed for high-dose estimations, but little attention has been given to its applicability for partial-body irradiations. In the present work we estimated the doses and the percentage of the irradiated fraction in simulated partial-body radiation exposures at high doses using the PCC-R assay. Peripheral whole blood of three healthy donors was exposed to doses from 0–20 Gy, with 60Co gamma radiation. To simulate partial body irradiations, irradiated and non-irradiated blood was mixed to obtain proportions of irradiated blood from 10–90%. Lymphocyte cultures were treated with Colcemid and Calyculin-A before harvest. Conventional and triage scores were performed for each dose, proportion of irradiated blood and donor. The Papworth's u test was used to evaluate the PCC-R distribution per cell. A dose-response relationship was fitted according to the maximum likelihood method using the frequencies of PCC-R obtained from 100% irradiated blood. The dose to the partially irradiated blood was estimated using the Contaminated Poisson method. A new D0 value of 10.9 Gy was calculated and used to estimate the initial fraction of irradiated cells. The results presented here indicate that by PCC-R it is possible to distinguish between simulated partial- and whole-body irradiations by the u-test, and to accurately estimate the dose from 10–20 Gy, and the initial fraction of irradiated cells in the interval from 10–90%. PMID:23596200

  13. The ionization potential of aqueous hydroxide computed using many-body perturbation theory

    SciTech Connect

    Opalka, Daniel Sprik, Michiel; Pham, Tuan Anh; Galli, Giulia

    2014-07-21

    The ionization potentials of electrolyte solutions provide important information about the electronic structure of liquids and solute-solvent interactions. We analyzed the positions of solute and solvent bands of aqueous hydroxide and the influence of the solvent environment on the ionization potential of hydroxide ions. We used the concept of a computational hydrogen electrode to define absolute band positions with respect to vacuum. We found that many-body perturbation theory in the G{sub 0} W{sub 0} approximation substantially improves the relative and absolute positions of the band edges of solute and solvent with respect to those obtained within Density Functional Theory, using semi-local functionals, yielding results in satisfactory agreement with recent experiments.

  14. Effects of dust-charge fluctuations on the potential of an array of projectiles in a partially ionized dusty plasma

    NASA Astrophysics Data System (ADS)

    Ali, S.; Nasim, M. H.; Murtaza, G.

    2003-11-01

    The expressions for the Debye and the wake potential are derived by incorporating dust-charge fluctuations of a single projectile, as well as of an array of dust grain projectiles, propagating through a partially ionized dusty plasma with a constant velocity. Numerically, the effects of the dust-charge fluctuations and the dust-neutral collisions on the electrostatic potential for a single, three, six and ten projectiles are examined. The dust-charge relaxation rate modifies the shape of the Debye as well as the wake potential. For smaller values of the relaxation rates a potential well is formed instead of Debye potential.

  15. Demystifying Introductory Chemistry. Part 3: Ionization Energies, Electronegativity, Polar Bonds, and Partial Charges.

    ERIC Educational Resources Information Center

    Spencer, James; And Others

    1996-01-01

    Shows how ionization energies provide a convenient method for obtaining electronegativity values that is simpler than the conventional methods. Demonstrates how approximate atomic charges can be calculated for polar molecules and how this method of determining electronegativities may lead to deeper insights than are typically possible for the…

  16. Coulomb three-body effects in low-energy impact ionization of H(1{ital s})

    SciTech Connect

    Roeder, J.; Rasch, J.; Jung, K.; Whelan, C.T.; Ehrhardt, H.; Allan, R.J.; Walters, H.R. |||

    1996-01-01

    The different kinematical and geometrical arrangements that may be used in ({ital e},2{ital e}) studies are briefly reviewed. The ionization of H(1{ital s}) is considered, and within the confines of a relatively simple theoretical model, it is shown how to define experimental setups where one may extract information on the role of Coulomb three-body effects in the incident and final channels. Theoretical and experimental results are presented for coplanar constant geometry where the focus is primarily on incident channel effects. {copyright} {ital 1996 The American Physical Society.}

  17. Chromosome aberrations induced in human lymphocytes after partial-body irradiation

    SciTech Connect

    Fong, L.; Lai-Lei Ting; Po-Ming Wang

    1995-10-01

    Chromosomal aberrations in peripheral blood lymphocytes obtained from two patients before and after they received one fraction of partial-body irradiation for palliative treatment were analyzed. Blood samples were taken 30 min and 24 h after radiation treatment. The yield of dicentrics obtained from case A 30 min after a partial-body (about 21%) treatment with 8 Gy was 0.066/cell, while the yield obtained 24 h radiation treatment was 0.071/cell. The fraction of irradiated lymphocytes that reached metaphase at 52 h was 0.08 as evaluated by mixing cultures of in vitro irradiated and unirradiated blood. The yield of dicentrics for blood from case B 30 min after 6 Gy partial-body (about 24%) irradiation was 0.655/cell, while the yield 24 h after irradiation was 0.605/cell. The fraction of irradiated cells was 0.29. Estimation of doses and irradiated fractions for the two cases using the method proposed by Dolphin and the Qdr method is discussed. Although there was no significant difference between the mean yields of dicentrics per cell obtained 30 min and 24 h after radiation treatment, the data obtained at 24 h seemed more useful for the purpose of dose estimation. When a higher dose (8 Gy) was delivered to a smaller percentage of the body, underestimation of the dose was encountered. 18 refs., 4 tabs.

  18. Time- and dose-dependent effects of total-body ionizing radiation on muscle stem cells.

    PubMed

    Masuda, Shinya; Hisamatsu, Tsubasa; Seko, Daiki; Urata, Yoshishige; Goto, Shinji; Li, Tao-Sheng; Ono, Yusuke

    2015-04-01

    Exposure to high levels of genotoxic stress, such as high-dose ionizing radiation, increases both cancer and noncancer risks. However, it remains debatable whether low-dose ionizing radiation reduces cellular function, or rather induces hormetic health benefits. Here, we investigated the effects of total-body γ-ray radiation on muscle stem cells, called satellite cells. Adult C57BL/6 mice were exposed to γ-radiation at low- to high-dose rates (low, 2 or 10 mGy/day; moderate, 50 mGy/day; high, 250 mGy/day) for 30 days. No hormetic responses in proliferation, differentiation, or self-renewal of satellite cells were observed in low-dose radiation-exposed mice at the acute phase. However, at the chronic phase, population expansion of satellite cell-derived progeny was slightly decreased in mice exposed to low-dose radiation. Taken together, low-dose ionizing irradiation may suppress satellite cell function, rather than induce hormetic health benefits, in skeletal muscle in adult mice. PMID:25869487

  19. Partial and full own-body illusions of epileptic origin in a child with right temporoparietal epilepsy.

    PubMed

    Heydrich, Lukas; Lopez, Christophe; Seeck, Margitta; Blanke, Olaf

    2011-03-01

    Partial and full own-body illusions of neurological origin have been claimed crucial to understand the contribution of bodily experience and perception to self-consciousness. Whereas partial body illusions are relatively common and well defined, much less is known about full own-body illusions, and even less is known about these illusions in children. Here we describe a 10-year-old patient with the association of partial and full own-body illusions (somatoparaphrenia and out-of-body experience) that occurred sequentially during an epileptic seizure caused by right temporoparietal epilepsy. This report shows that partial and full own-body illusions share functional and neuroanatomical properties and highlights the importance of the right temporoparietal junction for bodily self-consciousness. This is the first report of out-of-body experiences in a child with focal epilepsy. PMID:21334265

  20. Utilizing a shallow trench isolation parasitic transistor to characterize the total ionizing dose effect of partially-depleted silicon-on-insulator input/output n-MOSFETs

    NASA Astrophysics Data System (ADS)

    Peng, Chao; Hu, Zhi-Yuan; Ning, Bing-Xu; Huang, Hui-Xiang; Fan, Shuang; Zhang, Zheng-Xuan; Bi, Da-Wei; En, Yun-Fei

    2014-09-01

    We investigate the effects of 60Co γ-ray irradiation on the 130 nm partially-depleted silicon-on-isolator (PDSOI) input/output (I/O) n-MOSFETs. A shallow trench isolation (STI) parasitic transistor is responsible for the observed hump in the back-gate transfer characteristic curve. The STI parasitic transistor, in which the trench oxide acts as the gate oxide, is sensitive to the radiation, and it introduces a new way to characterize the total ionizing dose (TID) responses in the STI oxide. A radiation enhanced drain induced barrier lower (DIBL) effect is observed in the STI parasitic transistor. It is manifested as the drain bias dependence of the radiation-induced off-state leakage and the increase of the DIBL parameter in the STI parasitic transistor after irradiation. Increasing the doping concentration in the whole body region or just near the STI sidewall can increase the threshold voltage of the STI parasitic transistor, and further reduce the radiation-induced off-state leakage. Moreover, we find that the radiation-induced trapped charge in the buried oxide leads to an obvious front-gate threshold voltage shift through the coupling effect. The high doping concentration in the body can effectively suppress the radiation-induced coupling effect.

  1. COLLISIONLESS SHOCKS IN A PARTIALLY IONIZED MEDIUM. III. EFFICIENT COSMIC RAY ACCELERATION

    SciTech Connect

    Morlino, G.; Blasi, P.; Bandiera, R.; Amato, E.; Caprioli, D.

    2013-05-10

    In this paper, we present the first formulation of the theory of nonlinear particle acceleration in collisionless shocks in the presence of neutral hydrogen in the acceleration region. The dynamical reaction of the accelerated particles, the magnetic field amplification, and the magnetic dynamical effects on the shock are also included. The main new aspect of this study, however, consists of accounting for charge exchange and the ionization of a neutral hydrogen, which profoundly change the structure of the shock, as discussed in our previous work. This important dynamical effect of neutrals is mainly associated with the so-called neutral return flux, namely the return of hot neutrals from the downstream region to upstream, where they deposit energy and momentum through charge exchange and ionization. We also present the self-consistent calculation of Balmer line emission from the shock region and discuss how to use measurements of the anomalous width of the different components of the Balmer line to infer cosmic ray acceleration efficiency in supernova remnants showing Balmer emission: the broad Balmer line, which is due to charge exchange of hydrogen atoms with hot ions downstream of the shock, is shown to become narrower as a result of the energy drainage into cosmic rays, while the narrow Balmer line, due to charge exchange in the cosmic-ray-induced precursor, is shown to become broader. In addition to these two well-known components, the neutral return flux leads to the formation of a third component with an intermediate width: this too contains information on ongoing processes at the shock.

  2. Parasympathetic activity and blood catecholamine responses following a single partial-body cryostimulation and a whole-body cryostimulation.

    PubMed

    Hausswirth, Christophe; Schaal, Karine; Le Meur, Yann; Bieuzen, François; Filliard, Jean-Robert; Volondat, Marielle; Louis, Julien

    2013-01-01

    The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a

  3. Parasympathetic Activity and Blood Catecholamine Responses Following a Single Partial-Body Cryostimulation and a Whole-Body Cryostimulation

    PubMed Central

    Hausswirth, Christophe; Schaal, Karine; Le Meur, Yann; Bieuzen, François; Filliard, Jean-Robert; Volondat, Marielle; Louis, Julien

    2013-01-01

    The aim of this study was to compare the effects of a single whole-body cryostimulation (WBC) and a partial-body cryostimulation (PBC) (i.e., not exposing the head to cold) on indices of parasympathetic activity and blood catecholamines. Two groups of 15 participants were assigned either to a 3-min WBC or PBC session, while 10 participants constituted a control group (CON) not receiving any cryostimulation. Changes in thermal, physiological and subjective variables were recorded before and during the 20-min after each cryostimulation. According to a qualitative statistical analysis, an almost certain decrease in skin temperature was reported for all body regions immediately after the WBC (mean decrease±90% CL, -13.7±0.7°C) and PBC (-8.3±0.3°C), which persisted up to 20-min after the session. The tympanic temperature almost certainly decreased only after the WBC session (-0.32±0.04°C). Systolic and diastolic blood pressures were very likely increased after the WBC session, whereas these changes were trivial in the other groups. In addition, heart rate almost certainly decreased after PBC (-10.9%) and WBC (-15.2%) sessions, in a likely greater proportion for WBC compared to PBC. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal R-R intervals, RMSSD, and high frequency band, HF) were very likely increased after PBC (RMSSD: +54.4%, HF: +138%) and WBC (RMSSD: +85.2%, HF: +632%) sessions without any marked difference between groups. Plasma norepinephrine concentrations were likely to very likely increased after PBC (+57.4%) and WBC (+76.2%), respectively. Finally, cold and comfort sensations were almost certainly altered after WBC and PBC, sensation of discomfort being likely more pronounced after WBC than PBC. Both acute cryostimulation techniques effectively stimulated the autonomic nervous system (ANS), with a predominance of parasympathetic tone activation. The results of this study also suggest that a

  4. Investigation of unique total ionizing dose effects in 0.2 µm partially-depleted silicon-on-insulator technology

    NASA Astrophysics Data System (ADS)

    Zhang, YanWei; Huang, HuiXiang; Bi, DaWei; Tang, MingHua; Zhang, ZhengXuan

    2014-05-01

    The total ionizing dose (TID) radiation effects of partially-depleted (PD) silicon-on-insulator (SOI) devices fabricated in a commercial 0.2 μm SOI process were investigated. The experimental results show an original phenomenon: the "ON" irradiation bias configuration is the worst-case bias for both front-gate and back-gate transistors. To understand the mechanism, a charge distribution model is proposed. We consider that the performance degradation of the devices is due to the radiation-induced positive charge trapped in the bottom corner of Shallow Trench Isolation (STI) oxide. In addition, by comparing the irradiation responses of short and long channel devices under different drain biases, the short channel transistors show a larger degeneration of leakage current and threshold voltage. The dipole theory is introduced to explain the TID enhanced short channel effect.

  5. Calculations on charge state and energy loss of argon ions in partially and fully ionized carbon plasmas.

    PubMed

    Barriga-Carrasco, Manuel D; Casas, David; Morales, Roberto

    2016-03-01

    The energy loss of argon ions in a target depends on their velocity and charge density. At the energies studied in this work, it depends mostly on the free and bound electrons in the target. Here the random-phase approximation is used for analyzing free electrons at any degeneracy. For the plasma-bound electrons, an interpolation between approximations for low and high energies is applied. The Brandt-Kitagawa (BK) model is employed to depict the projectile charge space distribution, and the stripping criterion of Kreussler et al. is used to determine its equilibrium charge state Q(eq). This latter criterion implies that the equilibrium charge state depends slightly on the electron density and temperature of the plasma. On the other hand, the effective charge Q(eff) is obtained as the ratio between the energy loss of the argon ion and that of the proton for the same plasma conditions. This effective charge Q(eff) is larger than the equilibrium charge state Q(eq) due to the incorporation of the BK charge distribution. Though our charge-state estimations are not exactly the same as the experimental values, our energy loss agrees quite well with the experiments. It is noticed that the energy loss in plasmas is higher than that in the same cold target of about, ∼42-62.5% and increases with carbon plasma ionization. This confirms the well-known enhanced plasma stopping. It is also observed that only a small part of this energy loss enhancement is due to an increase of the argon charge state, namely only ∼2.2 and 5.1%, for the partially and the fully ionized plasma, respectively. The other contribution is connected with a better energy transfer to the free electrons at plasma state than to the bound electrons at solid state of about, ∼38.8-57.4%, where higher values correspond to a fully ionized carbon plasma. PMID:27078472

  6. Calculations on charge state and energy loss of argon ions in partially and fully ionized carbon plasmas

    NASA Astrophysics Data System (ADS)

    Barriga-Carrasco, Manuel D.; Casas, David; Morales, Roberto

    2016-03-01

    The energy loss of argon ions in a target depends on their velocity and charge density. At the energies studied in this work, it depends mostly on the free and bound electrons in the target. Here the random-phase approximation is used for analyzing free electrons at any degeneracy. For the plasma-bound electrons, an interpolation between approximations for low and high energies is applied. The Brandt-Kitagawa (BK) model is employed to depict the projectile charge space distribution, and the stripping criterion of Kreussler et al. is used to determine its equilibrium charge state Qeq. This latter criterion implies that the equilibrium charge state depends slightly on the electron density and temperature of the plasma. On the other hand, the effective charge Qeff is obtained as the ratio between the energy loss of the argon ion and that of the proton for the same plasma conditions. This effective charge Qeff is larger than the equilibrium charge state Qeq due to the incorporation of the BK charge distribution. Though our charge-state estimations are not exactly the same as the experimental values, our energy loss agrees quite well with the experiments. It is noticed that the energy loss in plasmas is higher than that in the same cold target of about, ˜42 -62.5 % and increases with carbon plasma ionization. This confirms the well-known enhanced plasma stopping. It is also observed that only a small part of this energy loss enhancement is due to an increase of the argon charge state, namely only ˜2.2 and 5.1 % , for the partially and the fully ionized plasma, respectively. The other contribution is connected with a better energy transfer to the free electrons at plasma state than to the bound electrons at solid state of about, ˜38.8 -57.4 % , where higher values correspond to a fully ionized carbon plasma.

  7. Risks of exposure to ionizing and millimeter-wave radiation from airport whole-body scanners.

    PubMed

    Moulder, John E

    2012-06-01

    Considerable public concern has been expressed around the world about the radiation risks posed by the backscatter (ionizing radiation) and millimeter-wave (nonionizing radiation) whole-body scanners that have been deployed at many airports. The backscatter and millimeter-wave scanners currently deployed in the U.S. almost certainly pose negligible radiation risks if used as intended, but their safety is difficult-to-impossible to prove using publicly accessible data. The scanners are widely disliked and often feared, which is a problem made worse by what appears to be a veil of secrecy that covers their specifications and dosimetry. Therefore, for these and future similar technologies to gain wide acceptance, more openness is needed, as is independent review and regulation. Publicly accessible, and preferably peer-reviewed evidence is needed that the deployed units (not just the prototypes) meet widely-accepted safety standards. It is also critical that risk-perception issues be handled more competently. PMID:22494369

  8. Two-centre partial-wave calculations for the multiply differential cross section of the simple ionization of diatomic lithium Li2 by fast electron impact

    NASA Astrophysics Data System (ADS)

    Elboudali, F.; Joulakian, B.

    2001-12-01

    The (e, 2e) ionization of diatomic lithium Li2 by fast electrons is studied by applying, for the slow ejected electron, an asymptotically exact partial-wave description, which takes into account the diatomic nature of the problem. The ionization is considered as a vertical transition from the lowest vibrational and rotational level of the fundamental electronic state 1Σg+ of Li2 to the fundamental 2Σg+ state of Li2+. After verification of the procedure on the (e, 2e) ionization of diatomic hydrogen H2 for which experimental and theoretical results exist we present the particularities and favourable directions for Li2 targets.

  9. Prevalence and Characteristics of Body Dysmorphic Disorder Among Patients in a Partial Hospital Program.

    PubMed

    Bjornsson, Andri; Magnusdottir, Soffia; Wessman, Inga; Beard, Courtney; Lee, Josephine; Hearon, Bridget A; Björgvinsson, Thröstur

    2016-07-01

    Body dysmorphic disorder (BDD) is a common disorder that is usually associated with impaired functioning and high levels of suicidality. The current study is the first to assess prevalence of BDD among patients in a partial hospital program and compare patients with and without BDD on demographic and clinical variables. Participants were 207 patients with a variety of Axis I diagnoses. Prevalence of current BDD was 7.2%, and a diagnosis of BDD did not predict worse treatment outcome in the program. Patients with current BDD were more likely to be female and younger and have more comorbid diagnoses than patients without current BDD. No other significant differences were found at baseline between patients with and without current BDD. Results indicate that BDD is relatively common among patients in partial hospital programs and that such programs may be as beneficial to patients with BDD as to other patients. PMID:27362701

  10. Electron impact fragmentation of adenine: partial ionization cross sections for positive fragments

    NASA Astrophysics Data System (ADS)

    van der Burgt, Peter J. M.; Finnegan, Sinead; Eden, Samuel

    2015-07-01

    Using computer-controlled data acquisition we have measured mass spectra of positive ions for electron impact on adenine, with electron energies up to 100 eV. Ion yield curves for 50 ions have been obtained and normalized by comparing their sum to the average of calculated total ionization cross sections. Appearance energies have been determined for 37 ions; for 20 ions for the first time. All appearance energies are consistent with the fragmentation pathways identified in the literature. Second onset energies have been determined for 12 fragment ions (for 11 ions for the first time), indicating the occurrence of more than one fragmentation process e.g. for 39 u (C2HN+) and 70 u (C2H4N3+). Matching ion yield shapes (118-120 u, 107-108 u, 91-92 u, and 54-56 u) provide new evidence supporting closely related fragmentation pathways and are attributed to hydrogen rearrangement immediately preceding the fragmentation. We present the first measurement of the ion yield curve of the doubly charged parent ion (67.5 u), with an appearance energy of 23.5 ± 1.0 eV. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey Solov'yov, Nigel Mason, Gustavo García, Eugene Surdutovich.

  11. Revisiting Biomarkers of Total-Body and Partial-Body Exposure in a Baboon Model of Irradiation

    PubMed Central

    Valente, Marco; Denis, Josiane; Grenier, Nancy; Arvers, Philippe; Foucher, Barbara; Desangles, François; Martigne, Patrick; Chaussard, Hervé; Drouet, Michel; Abend, Michael; Hérodin, Francis

    2015-01-01

    In case of a mass casualty radiation event, there is a need to distinguish total-body irradiation (TBI) and partial-body irradiation (PBI) to concentrate overwhelmed medical resources to the individuals that would develop an acute radiation syndrome (ARS) and need hematologic support (i.e., mostly TBI victims). To improve the identification and medical care of TBI versus PBI individuals, reliable biomarkers of exposure could be very useful. To investigate this issue, pairs of baboons (n = 18) were exposed to different situations of TBI and PBI corresponding to an equivalent of either 5 Gy 60Co gamma irradiation (5 Gy TBI; 7.5 Gy left hemibody/2.5 right hemibody TBI; 5.55 Gy 90% PBI; 6.25 Gy 80% PBI; 10 Gy 50% PBI, 15 Gy 30% PBI) or 2.5 Gy (2.5 Gy TBI; 5 Gy 50% PBI). More than fifty parameters were evaluated before and after irradiation at several time points up to 200 days. A partial least square discriminant analysis showed a good distinction of TBI from PBI situations that were equivalent to 5 Gy. Furthermore, all the animals were pooled in two groups, TBI (n = 6) and PBI (n = 12), for comparison using a logistic regression and a non parametric statistical test. Nine plasmatic biochemical markers and most of hematological parameters turned out to discriminate between TBI and PBI animals during the prodromal phase and the manifest illness phase. The most significant biomarkers were aspartate aminotransferase, creatine kinase, lactico dehydrogenase, urea, Flt3-ligand, iron, C-reactive protein, absolute neutrophil count and neutrophil-to-lymphocyte ratio for the early period, and Flt3-ligand, iron, platelet count, hemoglobin, monocyte count, absolute neutrophil count and neutrophil-to-lymphocyte ratio for the ARS phase. These results suggest that heterogeneity could be distinguished within a range of 2.5 to 5 Gy TBI. PMID:26177207

  12. Anelastic and thermal properties of ethylene/acrylic acid copolymers partially ionized with transition metals

    SciTech Connect

    Hoffman, D.M.; Matthews, F.M.; Riley, M.O.; Walkup, C.M.

    1988-01-01

    Ionomers of five 3d series transition metals (Mn, Fe, Co, Ni, and Cu), two Lanthanide series transition metals (Ce, Sm) and the IV and V series metals (Pb, Bi) were prepared by reaction with 25% solids dispersion of poly (ethylene-co-acrylic acid), EAA, in aqueous ammonia. The unreacted copolymer showed two mechanical relaxations, the glass transition at about 5C and a low temperature secondary relaxation at about -140C with 230 +- 10 kJ/mol and 50+-8 kJ/mol apparent activation energies, respectively. Typically three weight percent of the metal nitrate or acetate was reacted with the copolymer dispersion. After precipitation, drying and molding, the ionomers showed three mechanical relaxations. The low temperature ..gamma..-relaxation was quite strong and shifted about 5C higher compared to the EAA copolymer. The ..beta..-relaxation was extremely weak occurring at -62+-5C in the loss tangent at 1.0 Hz. The ..cap alpha..-relaxation or glass transition for 3% transition metal ionomers occurred at about 26+-3C for +3 oxidation states and Cu/sup +2/, but significantly higher for other +2 oxidation states (48 +- 2C for Co, Ni and 35C for Mn) based on G'' maxima at 1.0 Hz and the apparent activation energy was 220+-30kJ/mol. The two group IV and V metal ionomers were much higher loadings and had a much broader and stronger (..beta..') relaxation occurring at -6 +- 4C with 130+-10 kJ/mol activation energies. The lead ionomers were clear but the bismuth ionomer showed macroscopic phase separation. The 3d transition metal ionomers were clear and nicely colored characteristic of their ionization state except for iron which was somewhat cloudy. The Lanthanide ionomers were clear (Ce) or pale yellow (Sm) and also reasonably transparent. (16 refs., 12 figs., 5 tabs.)

  13. Coulomb three-body effects in ([ital e],2[ital e]) collisions: The ionization of H in coplanar symmetric geometry

    SciTech Connect

    Whelan, C.T.; Allan, R.J.; Rasch, J.; Walters, H.R.J.; Zhang, X.; Roeder, J.; Jung, K.; Ehrhardt, H. Daresbury Laboratory, Warrington WA4 4AD Department of Applied Mathematics and Theoretical Physics, The Queen's University of Belfast, BT7 1NN Belfast, Northern Ireland Fachbereich Physik, Universitaet Kaiserslautern, Erwin Schroedinger Strasse, D6750, Kaiserslautern )

    1994-11-01

    The role of postcollisional and polarization-correlation effects in energy-sharing ([ital e],2[ital e]) collisions is considered. Theoretical and experimental results are presented for the ionization of hydrogen in a symmetric coplanar geometry. A kinematical regime is identified where the triple-differential cross section is sensitive to three-body effects in both the incident and final channels.

  14. Calculation of total electron excitation cross-sections and partial electron ionization cross-sections for the elements. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Green, T. J.

    1973-01-01

    Computer programs were used to calculate the total electron excitation cross-section for atoms and the partial ionization cross-section. The approximations to the scattering amplitude used are as follows: (1) Born, Bethe, and Modified Bethe for non-exchange excitation; (2) Ochkur for exchange excitation; and (3) Coulomb-Born of non-exchange ionization. The amplitudes are related to the differential cross-sections which are integrated to give the total excitation (or partial ionization) cross-section for the collision. The atomic wave functions used are Hartree-Fock-Slater functions for bound states and the coulomb wave function for the continuum. The programs are presented and the results are examined.

  15. Improvements in the equation of state for the partially ionized plasmas of the solar interior

    NASA Astrophysics Data System (ADS)

    Liang, Aihua

    2005-11-01

    The three major material properties relevant for solar and stellar modeling are the equation of state (EOS), opacity and the nuclear reaction rate. Due to the nature of the equations of stellar structure and evolution, in most parts of a stars interior, the three material properties are entangled, and it is difficult to use astrophysics to constrain a single one. Luckily, thanks to the adiabatic stratification of the convection zone, there the structure only depends on the EOS, which is therefore largely disentangled from the other quantities. Our research, which aims at constraining the EOS using information from the Sun, is therefore most successful when data from the convection zone are used. Among the many solar equations of state that are being currently used there are two popular ones: Mihalas-Däppen-Hummer (MHD) EOS and OPAL EOS. Helioseismic inversion procedures, which have become standard to evaluate the accuracy of different solar models with respect to the real Sun, have revealed that except for the top 2%, the OPAL EOS matches the solar observations better than the MHD EOS. For this reason we have set our research goal to find a modification of the MHD EOS that can, in a first step, simulate the OPAL EOS, and ultimately, the real Sun. This goal has been attained. By construction, the OPAL EOS contains higher order correlation terms which are missing in the MHD EOS. Through an inversion procedure from the activity series expansion (ACTEX), upon which the OPAL EOS is based to the free energy expression of the MHD EOS, we have found out that the free particle assumption, used in the original version of the MHD EOS has indeed to be abandoned. We show that the two-body scattering terms of the Coulomb interaction, as well as electron degeneracy play a significant role in the difference between the original version of the MHD and OPAL EOS. During our interdisciplinary investigation, aiming at seeking an improved MHD EOS under the guidance of the OPAL EOS, we

  16. Jeans instability of partially-ionized self-gravitating viscous plasma with Hall effect FLR corrections and porosity

    NASA Astrophysics Data System (ADS)

    Kaothekar, Sachin; Soni, Ghanshyam D.; Prajapati, R. P.; Chhajlani, Rajendra K.

    2016-06-01

    The problem of Jeans gravitational instability and radiative instability is investigated for partially ionized self-gravitating plasma which has connection in astrophysical condensations and formation of objects. A general dispersion relation has been derived with the help of relevant linearized perturbation equations, using the normal mode analysis method. Effects of FLR corrections, radiative heat-loss function and collisions with neutrals on the Jeans criterion of self-gravitational instability of the system are discussed. The conditions of instability are derived for a temperature-dependent and density-dependent heat-loss function with thermal conductivity and FLR corrections for some special case. The stability of the system is discussed by using Routh-Hurwitz's criterion. Numerical calculations have been performed to discuss the dependence of the growth rate of the Jeans gravitational instability on the various physical parameters. The FLR corrections, viscosity, porosity, magnetic field, and neutral collision have stabilizing influence while finite electrical resistivity and permeability have a destabilizing influence on the growth rate of the gravitational instability. Our results are helpful for understanding the formation of dense molecular clouds.

  17. An experimental study of partial melting and fractional crystallization on the HED parent body

    NASA Astrophysics Data System (ADS)

    Ashcroft, Helen O.; Wood, Bernard J.

    2015-11-01

    We have performed an experimental and modeling study of the partial melting behavior of the HED parent body and of the fractional crystallization of liquids derived from its mantle. We estimated the mantle composition by assuming chondritic ratios of refractory lithophile elements, adjusting the Mg# and core size to match the density and moment of inertia of Vesta, and the compositions of Mg-rich olivines found in diogenites. The liquidus of a mantle with Mg# (=100*[Mg/(Mg+Fe)]) 80 is ~1625 °C and, under equilibrium conditions, the melt crystallizes olivine alone until it is joined by orthopyroxene at 1350 °C. We synthesized the melt from our 1350 °C experiment and simulated its fractional crystallization path. Orthopyroxene crystallizes until it is replaced by pigeonite at 1200 °C. Liquids become eucritic and crystal assemblages resemble diogenites below 1250 °C. MELTS correctly predicts the olivine liquidus but overestimates the orthopyroxene liquidus by ~70 °C. Predicted melt compositions are in reasonable agreement with those generated experimentally. We used MELTS to determine that the range of mantle compositions that can produce eucritic liquids and diogenitic solids in a magma ocean model is Mg# 75-80 (with chondritic ratios of refractory elements). A mantle with Mg# ~ 70 can produce eucrites and diogenites through sequential partial melting.

  18. Electron collisional detachment processes for a 250 keV D/sup -/ ion beam in a partially ionized hydrogen target

    SciTech Connect

    Savas, S.E.

    1980-09-01

    Neutral atom beams with energies above 200 keV may be required for various purposes in magnetic fusion devices following TFTR, JET and MFTF-B. These beams can be produced much more efficiently by electron detachment from negative ion beams than by electron capture by positive ions. We have investigated the efficiency with which such neutral atoms can be produced by electron detachment in partially ionized hydrogen plasma neutralizers.

  19. Free electron degeneracy effects on collisional excitation, ionization, de-excitation and three-body recombination

    NASA Astrophysics Data System (ADS)

    Tallents, G. J.

    2016-09-01

    Collisional-radiative models enable average ionization and ionization populations, plus the rates of absorption and emission of radiation to be calculated for plasmas not in thermal equilbrium. At high densities and low temperatures, electrons may have a high occupancy of the free electron quantum states and evaluations of rate coefficients need to take into account the free electron degeneracy. We demonstrate that electron degeneracy can reduce collisional rate coefficients by orders-of-magnitude from values calculated neglecting degeneracy. We show that assumptions regarding the collisional differential cross-section can alter collisional ionization and recombination rate coefficients by a further factor two under conditions relevant to inertial fusion.

  20. Magnetic Evidence for a Partially Differentiated Carbonaceous Chondrite Parent Body and Possible Implications for Asteroid 21 Lutetia

    NASA Astrophysics Data System (ADS)

    Weiss, Benjamin; Carporzen, L.; Elkins-Tanton, L.; Shuster, D. L.; Ebel, D. S.; Gattacceca, J.; Binzel, R. P.

    2010-10-01

    The origin of remanent magnetization in the CV carbonaceous chondrite Allende has been a longstanding mystery. The possibility of a core dynamo like that known for achondrite parent bodies has been discounted because chondrite parent bodies are assumed to be undifferentiated. Here we report that Allende's magnetization was acquired over several million years (Ma) during metasomatism on the parent planetesimal in a > 20 microtesla field 8-9 Ma after solar system formation. This field was present too recently and directionally stable for too long to have been the generated by the protoplanetary disk or young Sun. The field intensity is in the range expected for planetesimal core dynamos (Weiss et al. 2010), suggesting that CV chondrites are derived from the outer, unmelted layer of a partially differentiated body with a convecting metallic core (Elkins-Tanton et al. 2010). This suggests that asteroids with differentiated interiors could be present today but masked under chondritic surfaces. In fact, CV chondrites are spectrally similar to many members of the Eos asteroid family whose spectral diversity has been interpreted as evidence for a partially differentiated parent asteroid (Mothe-Diniz et al. 2008). CV chondrite spectral and polarimetric data also resemble those of asteroid 21 Lutetia (e.g., Belskaya et al. 2010), recently encountered by the Rosetta spacecraft. Ground-based measurements of Lutetia indicate a high density of 2.4-5.1 g cm-3 (Drummond et al. 2010), while radar data seem to rule out a metallic surface composition (Shepard et al. 2008). If Rosetta spacecraft measurements confirm a high density and a CV-like surface composition for Lutetia, then we propose Lutetia may be an example of a partially differentiated carbonaceous chondrite parent body. Regardless, the very existence of primitive achondrites, which contain evidence of both relict chondrules and partial melting, are prima facie evidence for the formation of partially differentiated bodies.

  1. Whole-body Mass Spectrometry Imaging by Infrared Matrix-assisted Laser Desorption Electrospray Ionization (IR-MALDESI).

    PubMed

    Nazari, Milad; Bokhart, Mark T; Muddiman, David C

    2016-01-01

    Ambient ionization sources for mass spectrometry (MS) have been the subject of much interest in the past decade. Matrix-assisted laser desorption electrospray ionization (MALDESI) is an example of such methods, where features of matrix-assisted laser desorption/ionization (MALDI) (e.g., pulsed nature of desorption) and electrospray ionization (ESI) (e.g., soft-ionization) are combined. One of the major advantages of MALDESI is its inherent versatility. In MALDESI experiments, an ultraviolet (UV) or infrared (IR) laser can be used to resonantly excite an endogenous or exogenous matrix. The choice of matrix is not analyte dependent, and depends solely on the laser wavelength used for excitation. In IR-MALDESI experiments, a thin layer of ice is deposited on the sample surface as an energy-absorbing matrix. The IR-MALDESI source geometry has been optimized using statistical design of experiments (DOE) for analysis of liquid samples as well as biological tissue specimens. Furthermore, a robust IR-MALDESI imaging source has been developed, where a tunable mid-IR laser is synchronized with a computer controlled XY translational stage and a high resolving power mass spectrometer. A custom graphical user interface (GUI) allows user selection of the repetition rate of the laser, number of shots per voxel, step-size of the sample stage, and the delay between the desorption and scan events for the source. IR-MALDESI has been used in variety of applications such as forensic analysis of fibers and dyes and MSI of biological tissue sections. Distribution of different analytes ranging from endogenous metabolites to exogenous xenobiotics within tissue sections can be measured and quantified using this technique. The protocol presented in this manuscript describes major steps necessary for IR-MALDESI MSI of whole-body tissue sections. PMID:27077488

  2. Partial-ionization cross sections of a CO{sub 2} molecule due to impact of 10-26-keV electrons

    SciTech Connect

    Bhatt, Pragya; Singh, Raj; Yadav, Namita; Shanker, R.

    2010-10-15

    Experimental data on total- and partial-ionization cross sections of ionic fragments of CO{sub 2} molecule produced by impact of 10-26-keV electrons are obtained on a crossed-beam apparatus in our laboratory. An ejected electron-produced ion-coincidence technique is employed together with a time-of-flight mass spectrometer for analysis of the ions. The six ionic fragments, CO{sub 2}{sup +}, CO{sup +}, CO{sub 2}{sup 2+}, O{sup +}, C{sup +}, and C{sup 2+}, resulting from dissociative ionization of the CO{sub 2} molecule are observed and identified; their relative ionization cross sections and branching ratios are determined as a function of impact energy. The binary-encounter Bethe model is found to overestimate the experimental data for total-ionization cross sections of the observed ions. No other experimental or theoretical data exist in the investigated energy range to make a direct comparison with the present results.

  3. Use of partial body-weight support for aggressive return to running after lumbar disk herniation: a case report.

    PubMed

    Moore, Melita N; Vandenakker-Albanese, Carol; Hoffman, Martin D

    2010-05-01

    This case report demonstrates the application of partial body-weight supported treadmill running in an aggressive rehabilitation program of an ultramarathon runner who had sustained a lumbar disk herniation. Body-weight supported exercise has recognized value during rehabilitation of lower-extremity injuries. In this case we found that the reductions in vertical loading forces achieved through partial body-weight support can also be valuable in the rehabilitation of an injury above the level of support. This motivated runner successfully used weight-supported treadmill training within 1 week of an acute lumbar disk herniation when he was experiencing considerable pain with unsupported walking and lower-extremity weakness. He continued its use until he adequately improved to allow return to his regular overground running program. This case demonstrates how partial body-weight support can allow aggressive running training early after a lumbar disk injury when normal impact forces cannot be tolerated and when leg weakness is a limitation. PMID:20434621

  4. Neutron and gamma detector using an ionization chamber with an integrated body and moderator

    DOEpatents

    Ianakiev, Kiril D.; Swinhoe, Martyn T.; Lestone, John Paul

    2006-07-18

    A detector for detecting neutrons and gamma radiation includes a cathode that defines an interior surface and an interior volume. A conductive neutron-capturing layer is disposed on the interior surface of the cathode and a plastic housing surrounds the cathode. A plastic lid is attached to the housing and encloses the interior volume of the cathode forming an ionization chamber, into the center of which an anode extends from the plastic lid. A working gas is disposed within the ionization chamber and a high biasing voltage is connected to the cathode. Processing electronics are coupled to the anode and process current pulses which are converted into Gaussian pulses, which are either counted as neutrons or integrated as gammas, in response to whether pulse amplitude crosses a neutron threshold. The detector according to the invention may be readily fabricated into single or multilayer detector arrays.

  5. Body fat distribution in women with familial partial lipodystrophy caused by mutation in the lamin A/C gene

    PubMed Central

    Monteiro, Luciana Z.; Foss-Freitas, Maria C.; Júnior Montenegro, Renan M.; Foss, Milton C.

    2012-01-01

    Familial partial lipodystrophy (FPLD), Dunnigan variety, is an autosomal dominant disorder caused due to missense mutations in the lamin A/C (LMNA) gene encoding nuclear lamina proteins. Patients with FPLD are predisposed to metabolic complications of insulin resistance such as diabetes. We sought to evaluate and compare body fat distribution with dual-emission X-ray absorptiometry in women with and without FPLD and identify densitometric, clinical and metabolic features. PMID:22276265

  6. Extraction and analysis of body-induced partials of guitar tones.

    PubMed

    Fréour, Vincent; Gautier, François; David, Bertrand; Curtit, Marthe

    2015-12-01

    Guitar plucked sounds arise from a rapid input of energy applied to the string coupled to the instrument body at the bridge. For the radiated pressure, this results in quasi-harmonic contributions, reflecting the string modes coupled to the body, as well as some transient and quickly decaying components reflecting the excitation of the body modes of the instrument. In order to evaluate the relevance of this transient body sound, a high resolution analysis-synthesis method is described for the extraction of the body-mode contribution from the radiated pressure measured in the near field of the guitar top plate. This analysis scheme is first tested on synthesized signals. Some body-sound emergence indicators are then proposed and computed over a pool of instruments. The influence of the conditions of excitation on the body-sound emergence is investigated, and the instruments categorized according to these objective descriptors. Results show a larger range of body-sound emergence with variations of the plucking position in hand-made guitars compared to industrial instruments. This suggests that these particular hand-made instruments are more sensitive to variations in the control from the player and hence allow a wider range of timbres with respect to the transient coloration of the body modes. PMID:26723347

  7. PIG (partially ionized globule) anatomy - Density and temperature structure of the bright-rimmed globule IC 1396E

    NASA Technical Reports Server (NTRS)

    Serabyn, E.; Guesten, R.; Mundy, L.

    1993-01-01

    The density and temperature structure of the bright-rimmed cometary globule IC 1396E is estimated, and the possibility that recent internal star formation was triggered by the ionization front in its southern surface is assessed. On the basis of NH3 data, gas temperatures in the globule are found to increase outward from the center, from a minimum of 17 K in its tail to a maximum of 26 K on the surface most directly facing the stars ionizing IC 1396. On the basis of a microturbulent radiative transfer code to model the radial dependence of the CS line intensities, and also the intensities of the optically thin 2-1 and 5-4 lines toward the cloud center, a radial density dependence of r exp -1.55 to r exp -1.75 is found.

  8. The aerodynamics of bodies in a rarefied ionized gas with applications to spacecraft environmental dynamics

    NASA Technical Reports Server (NTRS)

    Stone, N. H.

    1981-01-01

    The objectives are to provide a parametric description of the electrostatic interaction of a mesosonic, collisionless plasma with conducting bodies on the order of 1 to 10 Debye lengths in size, and to extend this description to the satellite-ionospheric interaction, where possible. Experimental findings include: the wake of the geometrically complex body appears to be a linear superposition of the wakes of its simple geometric components; and vector ion flux measurements show converging ion streams at the wake axis and direct evidence of ion streams deflected from the wake axis by the positive space charge potential associated with the axial ion peak. The extension to the satellite-ionospheric interaction utilizes qualitative scaling and indicates that similar, but smaller amplitude, wake structures may be expected for small or highly charged bodies. However, for large bodies at small potentials, the structure may be diffused by the thermal ion motion and the dispersion resulting for space charge potentials.

  9. COLLISIONLESS SHOCKS IN A PARTIALLY IONIZED MEDIUM. I. NEUTRAL RETURN FLUX AND ITS EFFECTS ON ACCELERATION OF TEST PARTICLES

    SciTech Connect

    Blasi, P.; Morlino, G.; Bandiera, R.; Amato, E.; Caprioli, D.

    2012-08-20

    A collisionless shock may be strongly modified by the presence of neutral atoms through the processes of charge exchange between ions and neutrals and ionization of the latter. These two processes lead to exchange of energy and momentum between charged and neutral particles both upstream and downstream of the shock. In particular, neutrals that suffer a charge exchange downstream with shock-heated ions generate high-velocity neutrals that have a finite probability of returning upstream. These neutrals might then deposit heat in the upstream plasma through ionization and charge exchange, thereby reducing the fluid Mach number. A consequence of this phenomenon, which we refer to as the neutral return flux, is a reduction of the shock compression factor and the formation of a shock precursor upstream. The scale length of the precursor is determined by the ionization and charge-exchange interaction lengths of fast neutrals moving toward upstream infinity. In the case of a shock propagating in the interstellar medium, the effects of ion-neutral interactions are especially important for shock velocities <3000 km s{sup -1}. Such propagation velocities are common among shocks associated with supernova remnants, the primary candidate sources for the acceleration of Galactic cosmic rays. We then investigate the effects of the return flux of neutrals on the spectrum of test particles accelerated at the shock. We find that, for shocks slower than {approx}3000 km s{sup -1}, the particle energy spectrum steepens appreciably with respect to the naive expectation for a strong shock, namely, {proportional_to}E{sup -2}.

  10. Generation of three-dimensional body-fitted grids by solving hyperbolic partial differential equations

    NASA Technical Reports Server (NTRS)

    Steger, Joseph L.

    1989-01-01

    Hyperbolic grid generation procedures are described which have been used in external flow simulations about complex configurations. For many practical applications a single well-ordered (i.e., structured) grid can be used to mesh an entire configuration, in other problems, composite or unstructured grid procedures are needed. Although the hyperbolic partial differential equation grid generation procedure has mainly been utilized to generate structured grids, an extension of the procedure to semiunstructured grids is briefly described. Extensions of the methodology are also described using two-dimensional equations.

  11. Diagnostic signature of low-energy secondary electron emission at the boundary of a partially-ionized plasma

    NASA Astrophysics Data System (ADS)

    Demidov, V. I.; Adams, S. F.; Kaganovich, I. D.; Koepke, M. E.; Kurlyandskaya, I. P.

    2015-09-01

    Effects of secondary electron emission (SEE) from a solid surface in contact with plasma are important for conducting and interpreting plasma experiments and modeling. Those effects are especially strong for contaminated surfaces. Measurements of SEE reported here are conducted in a plasma having a nearly mono-energetic population of electrons that is energetically well resolved and separated from a broader-energy-range electron population. By performing the SEE measurement in an afterglow or afterglow-like plasma, we take advantage of the nearly mono-energetic electron population that arises in ionizing plasma-chemical reactions, such as binary like-particle collisions of metastable atoms. We demonstrate a diagnostic method for measuring the low-energy electron absorption coefficient across the broader energy range and the effects of contamination on the swept-bias probe characteristic trace. A part of this research was performed while VID held a National Research Council Research Associateship Award at AFRL.

  12. Partially ionized gas flow and heat transfer in the separation, reattachment, and redevelopment regions downstream of an abrupt circular channel expansion.

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Massier, P. F.; Roschke, E. J.

    1972-01-01

    Heat transfer and pressure measurements obtained in the separation, reattachment, and redevelopment regions along a tube and nozzle located downstream of an abrupt channel expansion are presented for a very high enthalpy flow of argon. The ionization energy fraction extended up to 0.6 at the tube inlet just downstream of the arc heater. Reattachment resulted from the growth of an instability in the vortex sheet-like shear layer between the central jet that discharged into the tube and the reverse flow along the wall at the lower Reynolds numbers, as indicated by water flow visualization studies which were found to dynamically model the high-temperature gas flow. A reasonably good prediction of the heat transfer in the reattachment region where the highest heat transfer occurred and in the redevelopment region downstream can be made by using existing laminar boundary layer theory for a partially ionized gas. In the experiments as much as 90 per cent of the inlet energy was lost by heat transfer to the tube and the nozzle wall.

  13. More evidence for a partially differentiated CV chondrite parent body from paleomagnetic studies of ALH 84028 and ALH 85006

    NASA Astrophysics Data System (ADS)

    Klein, B. Z.; Weiss, B. P.; Carporzen, L.

    2014-12-01

    Recent paleomagnetic studies of the CV carbonaceous chondrites Allende and Kaba and numerical modeling studies have suggested that the CV chondrite parent body may have been partially differentiated, with a molten metallic core, dynamo magnetic field, and an unmelted chondritic lid. To further evaluate this hypothesis, here we present new paleomagnetic analyses of two previously unstudied CV3 chondrites: the unshocked, Allende-type oxidized chondrite ALH 84028 and the weakly shocked, Bali-type oxidized chondrite ALH 85006. We preformed alternating field (AF) and thermal demagnetization experiments, AF-based paleointensity experiments, and rock magnetic experiments on mutually oriented subsamples of each meteorite. Both meteorites pass fusion crust baked contact tests, indicating that their interiors retain a magnetization predating atmospheric entry. In the interior of ALH 84028, we identified a unidirectional medium temperature (blocked to 300°C), high coercivity (blocked to >420 mT) component. In the interior of ALH 85006, we identified MT components blocked up to 400-475°C. The unblocking temperatures and unidirectional nature of the MT components in both meteorites indicates their origin as a partial thermoremanence or thermochemical remanence acquired during metamorphism following accretion of the CV chondrite parent body. Our paleointensity experiments indicate paleofield intensities of 32-73 μT for ALH 84028 and 14-45 μT for ALH 85006 . When combined with similar recent results for Allende and Kaba, there is now consistent evidence for dynamo fields from four CV chondrites with collectively diverse lithologies and shock states. Therefore, the magnetic field on the CV parent body was not a localized event like that expected for a field generated by meteoroid impact plasmas and instead likely had a wide spatial extent. Further, given the younger I-Xe ages for Kaba compared to Allende (9-10 Ma and 2-3 Ma after Stillwater respectively), CV parent body

  14. [Modification of the body's resistance to acute ionizing radiation by synthetic beta-carotene].

    PubMed

    Beliaev, I K; Zaraĭskiĭ, A V; Limberg, V K; Vakulova, L A

    1992-01-01

    Radiomodifying efficiency of short-term and chronic medicinal and treatment-prophylactic enrichment of rations with artificial beta-carotene, administered at single doses of 0.1-10.0 mg, were studied after acute external gamma-irradiation of adult nonlinear and Wistar rats (0.029 Gy/s) or female SBA mice (0.0037 Gy/s), where the absorbed dose was equal to 8-3 Gy or 9.9-9.5 Gy, respectively. Suspension of beta-carotene paste in olive oil accelerated death of rats irradiated at doses of 8 and 7 Gy (P = 0.04), and shortened their lifespan. At a dose of 6 Gy single and long-term enrichment of rations with beta-carotene decreased the rate of rat death within 30 days from 33.3% to 16.7% (P = 0.14) and 3.3% (P = 0.01), while their life time was increased from 48 days to 67 days (P = 0.05) and 508 days (P = 0.01). beta-Carotene was found to affect favourably the radiation-induced (5 Gy) leukocytopenia, and decreased thymus mass (6 Gy) and body weight (8 Gy). In treatment-prophylactic enrichment with beta-carotene of mice (9.9 Gy) ration their survival was increased from 15% to 30% and lifespan from 14.4 days to 28.9 days (P = 0.05). During medicinal or treatment-prophylactic courses of beta-carotene death of mice (9.7 Gy) was decreased from 75% to 35% (P = 0.01) or 60% and life time was increased from 16.7 days to 22.17 days or 39.9 days (P = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1298128

  15. Food Reinforcement Partially Mediates the Effect of Socioeconomic Status on Body Mass Index

    PubMed Central

    Lin, Henry; Carr, Katelyn A.; Fletcher, Kelly D.; Epstein, Leonard H.

    2012-01-01

    Low socioeconomic status (low SES), as defined by income or educational attainment, has been associated with obesity in industrialized nations. Low SES persons have limited resources and may experience food insecurity that increases food reinforcement. Food reinforcement has been positively related to energy intake and weight status, and increased food reinforcement may explain the higher prevalence of obesity among low SES individuals who have restricted access to low-energy-dense foods and non-food reinforcers. We measured annual household income, highest education level completed and food reinforcement in 166 adults of varying body mass index (BMI, kg/m2). Multivariate linear regression analyses controlling for age, sex, minority status, session hunger and the reinforcing value of non-food alternatives showed that household income was related to food reinforcement (p = 0.048) and BMI (p = 0.019), and that food reinforcement was related to BMI (p = 0.0017). Path analyses revealed a significant indirect effect of household income on BMI through food reinforcement, suggesting that the relationship between lower household income and greater BMI was mediated in part by increased food reinforcement. A similar pattern of results was observed when education level was used as the proxy for SES. These findings support the hypothesis that deprivation and restricted food choice associated with low SES enhance food reinforcement, increasing the risk for obesity. PMID:23754824

  16. Resonance behaviour and partial averaging in a three-body system with gravitational radiation damping

    NASA Astrophysics Data System (ADS)

    Wardell, Zachary E.

    2003-05-01

    In a previous investigation, a model of three-body motion was developed which included the effects of gravitational radiation reaction. The aim was to describe the motion of a relativistic binary pulsar that is perturbed by a third mass and look for resonances between the binary and third-mass orbits. Numerical integration of an equation of relative motion that approximates the binary gives evidence of such resonances. These (m:n) resonances are defined for the present purposes by the resonance condition, mω= 2nΩ, where m and n are relatively prime integers and ω and Ω are the angular frequencies of the binary orbit and third-mass orbit (around the centre of mass of the binary), respectively. The resonance condition consequently fixes a value for the semimajor axis a of the binary orbit for the duration of the resonance because of the Kepler relationship ω=a-3/2. This paper outlines a method of averaging developed by Chicone, Mashhoon and Retzloff, which renders a non-linear system that undergoes resonance capture into a mathematically amenable form. This method is applied to the present system and one arrives at an analytical solution that describes the average motion during resonance. Furthermore, prominent features of the full non-linear system, such as the frequency of oscillation and antidamping, accord with their analytically derived formulae.

  17. Kidney and lung injury in irradiated rats protected from acute death by partial-body shielding

    SciTech Connect

    Geraci, J.P.; Jackson, K.L.; Mariano, M.S.; Michieli, B.M. )

    1990-04-01

    Ninety-six CD-1 male rats were exposed to gamma-ray doses (0-25 Gy) in increments of 5 Gy. One femur, the surgically exteriorized GI tract, and the oral cavity were shielded during irradiation to protect against acute mortality from injury to the hematopoietic system, small intestine, and oral cavity. In addition, the thoraxes of half of the animals from each dose group were shielded. At approximately monthly intervals from 2 to 10 months after irradiation the hematocrit, plasma urea nitrogen (PUN), and {sup 51}Cr-EDTA clearance were measured. During the study 20 thorax-shielded and 19 thorax-irradiated animals died. All rats whose thoraxes received 25 Gy irradiation and three out of seven rats whose thoraxes received 20 Gy died 1 to 3 months postirradiation with massive pleural fluid accumulation. Shielding the thoraxes prevented this mode of death at these doses. Kidney injury was judged to be the primary cause of death of all thorax-shielded animals and 15- and 20-Gy thorax-irradiated animals. Animals with kidney damage had elevated PUN and reduced {sup 51}Cr-EDTA clearance and hematocrits. The relative merits of each of these end points in assessing radiation-induced kidney injury after total-body exposure are discussed.

  18. Characterization of partially transesterified poly(beta-hydroxyalkanoate)s using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Saeed; Ayorinde; Eribo; Gordon; Collier

    1999-10-15

    Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used for the characterization of a partially transesterified poly(beta-hydroxyalkanoate), PHA, polymer produced by the bacterial strain Alcaligenes eutrophus using saponified vegetable oils as the sole carbon sources. The transesterification was carried out separately under acidic and basic conditions to obtain PHA oligomers weighing less than 10 kDa. The intact oligomers were detected in their cationized [M + Na](+) and [M + K](+) forms by MALDI-TOFMS. A composition analysis, using the MALDI-TOF spectra, indicate that the oligomers obtained via acid catalysis were terminated with a methyl 3-hydroxybutyrate end group, and those obtained by base catalysis had a methyl crotonate (olefinic) termination. In addition to HB (hydroxy butyrate), the oligomers were found to contain a small percentage of HV (hydroxy valerate). This was independently confirmed using gas chromatography/mass spectrometry (GC/MS). In comparison, the analysis of a commercial PHA polymer, transesterified under identical conditions, only showed the presence of HB, i.e. a pure PHB homopolymer. Copyright 1999 John Wiley & Sons, Ltd. PMID:10487942

  19. Use of a partial filling technique and reverse migrating micelles in the study of N-methylcarbamate pesticides by micellar electrokinetic chromatography-electrospray ionization mass spectrometry.

    PubMed

    Molina, M; Wiedmer, S K; Jussila, M; Silva, M; Riekkola, M L

    2001-08-24

    This study describes three ways to couple micellar electrokinetic chromatography (MEKC) on-line with electrospray ionization mass spectrometry (ESI-MS) for the analysis of N-methylcarbamate pesticides. The methods involved the use of a partial filling (PF) technique under basic conditions and the use of reverse migrating micelles (RMMs) under acidic and basic conditions. The use of RMMs in basic electrolyte solutions required coated capillaries with low electroosmotic flows, and capillaries coated with anionic poly(sodium 2-acrylamide-2-methylpropanesulfonate) were selected for the purpose. Before the on-line MEKC-ESI-MS coupling, the MEKC and MS conditions were separately optimized under off-line conditions. The methods were compared in terms of detection limits and the stability of the electrospray process. The PF method offered good separation but poorer stability of the electrospray relative to the other methods. A more stable electrospray performance was obtained with use of RMMs in acidic electrolyte solutions, but some of the analytes were protonated and could not be detected due to the increase in their retention factors. However, with the use of anionic polymer-coated capillaries and RMMs at pH 8.5, all analytes were successfully separated. The high-salt stacking method was applied to improve the sensitivity of MEKC-ESI-MS and the detection limits were in the range of 0.04-2.0 microg/ml. PMID:11572389

  20. Effect of neutral collision and radiative heat-loss function on self-gravitational instability of viscous thermally conducting partially-ionized plasma

    SciTech Connect

    Kaothekar, Sachin; Soni, Ghanshyam D.; Chhajlani, Rajendra K.

    2012-12-15

    The problem of thermal instability and gravitational instability is investigated for a partially ionized self-gravitating plasma which has connection in astrophysical condensations. We use normal mode analysis method in this problem. The general dispersion relation is derived using linearized perturbation equations of the problem. Effects of collisions with neutrals, radiative heat-loss function, viscosity, thermal conductivity and magnetic field strength, on the instability of the system are discussed. The conditions of instability are derived for a temperature-dependent and density-dependent heat-loss function with thermal conductivity. Numerical calculations have been performed to discuss the effect of various physical parameters on the growth rate of the gravitational instability. The temperature-dependent heat-loss function, thermal conductivity, viscosity, magnetic field and neutral collision have stabilizing effect, while density-dependent heat-loss function has a destabilizing effect on the growth rate of the gravitational instability. With the help of Routh-Hurwitz's criterion, the stability of the system is discussed.

  1. Changes in partial pressures of respiratory gases during submerged voluntary breath hold across odontocetes: is body mass important?

    PubMed

    Noren, S R; Williams, T M; Ramirez, K; Boehm, J; Glenn, M; Cornell, L

    2012-02-01

    Odontocetes have an exceptional range in body mass spanning 10(3) kg across species. Because, size influences oxygen utilization and carbon dioxide production rates in mammals, this lineage likely displays an extraordinary variation in oxygen store management compared to other marine mammal groups. To examine this, we measured changes in the partial pressures of respiratory gases ([Formula: see text], [Formula: see text]), pH, and lactate in the blood during voluntary, quiescent, submerged breath holds in Pacific white-sided dolphins (Lagenorhynchus obliquidens), bottlenose dolphins (Tursiops truncatus), and a killer whale (Orcinus orca) representing a mass range of 96-3,850 kg. These measurements provided an empirical determination of the effect of body size on the variability in blood biochemistry during breath hold and experimentally determined aerobic dive limits (ADL) within one taxonomic group (odontocetes). For the species in this study, maximum voluntary breath-hold duration was positively correlated with body mass, ranging from 3.5 min in white-sided dolphins to 13.3 min for the killer whale. Variation in breath-hold duration was associated with differences in the rate of change for [Formula: see text] throughout breath hold; [Formula: see text] decreased twice as fast for the two smaller species (-0.6 mmHg O(2) min(-1)) compared to the largest species (-0.3 mmHg O(2) min(-1)). In contrast, the rate of increase in [Formula: see text] during breath hold was similar across species. These results demonstrate that large body size in odontocetes facilitates increased aerobic breath-hold capacity as mediated by decreased mass-specific metabolic rates (rates of change in [Formula: see text] served as a proxy for oxygen utilization). Indeed the experimentally determined 5 min ADL for bottlenose dolphins was surpassed by the 13.3 min maximum breath hold of the killer whale, which did not end in a rise in lactate. Rather, breath hold ended voluntarily as respiratory

  2. Large area neutron detector based on Li6 ionization chamber with integrated body-moderator of high density polyethylene

    SciTech Connect

    Ianakiev, Kiril D.; Swinhoe, Martyn T.; Chung, Kiwhan; Makela, Mark F.

    2009-06-30

    A detector was developed and funded by DHS to be a lower cost alternative to 3He detectors. A 6Li foil-lined ionization chamber was prepared with fill gas at one atmosphere and pulse mode operation. The high-density polyethylene (HOPE) body serves also as a neutron moderator. All electrodes, including high voltage bias supply, are hermetically sealed within the plastic slabs.

  3. Antioxidant Approaches to Management of Ionizing Irradiation Injury

    PubMed Central

    Greenberger, Joel; Kagan, Valerian; Bayir, Hulya; Wipf, Peter; Epperly, Michael

    2015-01-01

    Ionizing irradiation induces acute and chronic injury to tissues and organs. Applications of antioxidant therapies for the management of ionizing irradiation injury fall into three categories: (1) radiation counter measures against total or partial body irradiation; (2) normal tissue protection against acute organ specific ionizing irradiation injury; and (3) prevention of chronic/late radiation tissue and organ injury. The development of antioxidant therapies to ameliorate ionizing irradiation injury began with initial studies on gene therapy using Manganese Superoxide Dismutase (MnSOD) transgene approaches and evolved into applications of small molecule radiation protectors and mitigators. The understanding of the multiple steps in ionizing radiation-induced cellular, tissue, and organ injury, as well as total body effects is required to optimize the use of antioxidant therapies, and to sequence such approaches with targeted therapies for the multiple steps in the irradiation damage response. PMID:26785339

  4. Antioxidant Approaches to Management of Ionizing Irradiation Injury.

    PubMed

    Greenberger, Joel; Kagan, Valerian; Bayir, Hulya; Wipf, Peter; Epperly, Michael

    2015-01-01

    Ionizing irradiation induces acute and chronic injury to tissues and organs. Applications of antioxidant therapies for the management of ionizing irradiation injury fall into three categories: (1) radiation counter measures against total or partial body irradiation; (2) normal tissue protection against acute organ specific ionizing irradiation injury; and (3) prevention of chronic/late radiation tissue and organ injury. The development of antioxidant therapies to ameliorate ionizing irradiation injury began with initial studies on gene therapy using Manganese Superoxide Dismutase (MnSOD) transgene approaches and evolved into applications of small molecule radiation protectors and mitigators. The understanding of the multiple steps in ionizing radiation-induced cellular, tissue, and organ injury, as well as total body effects is required to optimize the use of antioxidant therapies, and to sequence such approaches with targeted therapies for the multiple steps in the irradiation damage response. PMID:26785339

  5. Partial least squares analysis of rocket propulsion fuel data using diaphragm valve-based comprehensive two-dimensional gas chromatography coupled with flame ionization detection.

    PubMed

    Freye, Chris E; Fitz, Brian D; Billingsley, Matthew C; Synovec, Robert E

    2016-06-01

    The chemical composition and several physical properties of RP-1 fuels were studied using comprehensive two-dimensional (2D) gas chromatography (GC×GC) coupled with flame ionization detection (FID). A "reversed column" GC×GC configuration was implemented with a RTX-wax column on the first dimension ((1)D), and a RTX-1 as the second dimension ((2)D). Modulation was achieved using a high temperature diaphragm valve mounted directly in the oven. Using leave-one-out cross-validation (LOOCV), the summed GC×GC-FID signal of three compound-class selective 2D regions (alkanes, cycloalkanes, and aromatics) was regressed against previously measured ASTM derived values for these compound classes, yielding root mean square errors of cross validation (RMSECV) of 0.855, 0.734, and 0.530mass%, respectively. For comparison, using partial least squares (PLS) analysis with LOOCV, the GC×GC-FID signal of the entire 2D separations was regressed against the same ASTM values, yielding a linear trend for the three compound classes (alkanes, cycloalkanes, and aromatics), yielding RMSECV values of 1.52, 2.76, and 0.945 mass%, respectively. Additionally, a more detailed PLS analysis was undertaken of the compounds classes (n-alkanes, iso-alkanes, mono-, di-, and tri-cycloalkanes, and aromatics), and of physical properties previously determined by ASTM methods (such as net heat of combustion, hydrogen content, density, kinematic viscosity, sustained boiling temperature and vapor rise temperature). Results from these PLS studies using the relatively simple to use and inexpensive GC×GC-FID instrumental platform are compared to previously reported results using the GC×GC-TOFMS instrumental platform. PMID:27130110

  6. Kinetic-Hydrodynamic Models of the Solar Wind Interaction with the Partially Ionized Supersonic Flow of the Local Interstellar Gas: Predictions and Interpretations of the Experimental Data

    NASA Astrophysics Data System (ADS)

    Baranov, Vladimir B.

    2009-02-01

    At present there is no doubt that the local interstellar medium (LISM) is mainly partially ionized hydrogen gas moving with a supersonic flow relative to the solar system. The bulk velocity of this flow is approximately equal ˜26 km/s. Although the interaction of the solar wind with the charged component (below plasma component) of the LISM can be described in the framework of hydrodynamic approach, the interaction of H atoms with the plasma component can be correctly described only in the framework of kinetic theory because the mean free path of H atoms in the main process of the resonance charge exchange is comparable with a characteristic length of the problem considered. Results of self-consistent, kinetic-hydrodynamic models are considered in this review paper. First, such the model was constructed by Baranov and Malama (J. Geophys. Res. 98(A9):15,157-15,163, 1993). Up to now it is mainly developed by Moscow group taking into account new experimental data obtained onboard spacecraft studying outer regions of the solar system (Voyager 1 and 2, Pioneer 10 and 11, Hubble Space Telescope, Ulysses, SOHO and so on). Predictions and interpretations of experimental data obtained on the basis of these models are presented. Kinetic models for describing H atom motion were later suggested by Fahr et al. (Astron. Astrophys 298:587-600, 1995) and Lipatov et al. (J. Geophys. Res. 103(A9):20,631-20,642, 1998). However they were not self-consistent and did not incorporate sources to the plasma component. A self-consistent kinetic-hydrodynamic model suggested by Heerikhuisen et al. (J. Geophys. Res. 111:A06110, 2006, Astrophys. J. 655:L53-L56, 2007) was not tested on the results by Baranov and Malama (J. Geophys. Res. 111:A06110, 1993) although it was suggested much later. Besides authors did not describe in details their Monte Carlo method for a solution of the H atom Boltzmann equation and did not inform about an accuracy of this method. Therefore the results of

  7. Enhanced Total Ionizing Dose Hardness of Deep Sub-Micron Partially Depleted Silicon-on-Insulator n-Type Metal-Oxide-Semiconductor Field Effect Transistors by Applying Larger Back-Gate Voltage Stress

    NASA Astrophysics Data System (ADS)

    Zheng, Qi-Wen; Cui, Jiang-Wei; Yu, Xue-Feng; Guo, Qi; Zhou, Hang; Ren, Di-Yuan

    2014-12-01

    The larger back-gate voltage stress is applied on 130 nm partially depleted silicon-on-insulator n-type metal-oxide-semiconductor field-effect transistors isolated by shallow trench isolation. The experimental results show that the back-gate sub-threshold hump of the device is eliminated by stress. This observed behavior is caused by the high electric field in the oxide near the bottom corner of the silicon island. The total ionizing dose hardness of devices with pre back-gate stress is enhanced by the interface states induced by stress.

  8. Boundary-fitted curvilinear coordinate systems for solution of partial differential equations on fields containing any number of arbitrary two-dimensional bodies

    NASA Technical Reports Server (NTRS)

    Thompson, J. F.; Thames, F. C.; Mastin, C. W.

    1977-01-01

    A method is presented for automatic numerical generation of a general curvilinear coordinate system with coordinate lines coincident with all boundaries of a general multi-connected two-dimensional region containing any number of arbitrarily shaped bodies. No restrictions are placed on the shape of the boundaries, which may even be time-dependent, and the approach is not restricted in principle to two dimensions. With this procedure the numerical solution of a partial differential system may be done on a fixed rectangular field with a square mesh with no interpolation required regardless of the shape of the physical boundaries, regardless of the spacing of the curvilinear coordinate lines in the physical field, and regardless of the movement of the coordinate system in the physical plane. A number of examples of coordinate systems and application thereof to the solution of partial differential equations are given. The FORTRAN computer program and instructions for use are included.

  9. Comparison of two equation-of-state models for partially ionized aluminum: Zel'dovich and Raizer's model versus the activity expansion code

    NASA Astrophysics Data System (ADS)

    Harrach, Robert J.; Rogers, Forest J.

    1981-09-01

    Two equation-of-state (EOS) models for multipy ionized matter are evaluated for the case of an aluminum plasma in the temperature range from about one eV to several hundred eV, spanning conditions of weak to strong ionization. Specifically, the simple analytical mode of Zel'dovich and Raizer and the more comprehensive model comprised by Rogers' plasma physics avtivity expansion code (ACTEX) are used to calculate the specific internal energy ɛ and average degree of ionization Z¯*, as functons of temperature T and density ρ. In the absence of experimental data, these results are compared against each other, covering almost five orders-of-magnitude variation in ɛ and the full range of Z¯* We find generally good agreement between the two sets of results, especially for low densities and for temperatures near the upper end of the rage. Calculated values of ɛ(T) agree to within ±30% over nearly the full range in T for densities below about 1 g/cm3. Similarly, the two models predict values of Z¯*(T) which track each other fairly well; above 20 eV the discrepancy is less than ±20% fpr ρ≲1 g/cm3. Where the calculations disagree, we expect the ACTEX code to be more accurate than Zel'dovich and Raizer's model, by virtue of its more detailed physics content.

  10. Comparison of the effects of partial-or-whole-body exposures to 16O particles on cognitive performance in rats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Studies using a ground-based system (NASA Space Radiation Laboratory) to study the effects of exposure to particles of high energy and charge (HZE particles) on cognitive performance have interchangeably used whole-body exposures or exposures restricted to the head of the subject. It is possible th...

  11. Generation of three-dimensional body-fitted grids by solving hyperbolic and parabolic partial differential equations

    NASA Technical Reports Server (NTRS)

    Steger, Joseph L.

    1989-01-01

    Hyperbolic grid generation procedures are described which have been used in external flow simulations about complex configurations. For many practical applications a single well-ordered (i.e., structured) grid can be used to mesh an entire configuration, in other problems, composite or unstructured grid procedures are needed. Although the hyperbolic partial differential equation grid generation procedure has mainly been utilized to generate structured grids, extension of the procedure to semiunstructured grids is briefly described. Extensions of the methodology are also described using two-dimensional equations.

  12. Comparison of Drug Distribution Images from Thin Tissue Sections Obtained Using Desorption Electrospray Ionization Tandem Mass Spectrometry and Whole-Body Autoradiography

    SciTech Connect

    Kertesz, Vilmos; Van Berkel, Gary J; Vavek, Marissa; Koeplinger, Kenneth A.; Schneider, Bradley B; Covey, Thomas R.

    2008-01-01

    Desorption electrospray ionization tandem mass spectrometry (DESI-MS/MS) and whole-body autoradiography (WBA) were used for chemical imaging of whole-body thin tissue sections of mice intravenously dosed with propranolol (7.5 mg/kg). DESI-MS/MS imaging utilized selected reaction monitoring detection performed on an AB/MDS SCIEX 4000 QTRAP mass spectrometer equipped with a prototype extended length particle discriminator interface. Propranolol images of the tissue sections using DESI-MS/MS were obtained at surface scan rates of 0.1, 0.5, 2 and 7 mm/s. Although signal decreased with increasing scan rate, useful whole-body images for propranolol were obtained from the tissues even at 7 mm/s, which required just 79 min of analysis time. Attempts to detect and image the distribution of the known propranolol metabolites were unsuccessful. Regions of the tissue sections showing the most radioactivity from WBA sections were excised and analyzed by HPLC with radiochemical detection to determine relative levels of propranolol and metabolites present. Comparison of the DESI-MS/MS signal for propranolol and the radioactivity attributed to propranolol from WBA sections indicated nominal agreement between the two techniques for the amount of propranolol in the brain, lung, and liver. Data from the kidney showed an unexplained disparity between the two techniques. The results of this study show the feasibility of using DESI-MS/MS to obtain useful chemical images of a drug in whole-body thin tissue sections following drug administration at a pharmacologically relevant level. Further optimization to improve sensitivity and enable detection of the drug metabolites will be among the requirements necessary to move DESI-MS/MS chemical imaging forward as a practical tool in drug discovery.

  13. Whole-Body Vibration Partially Reverses Aging-Induced Increases in Visceral Adiposity and Hepatic Lipid Storage in Mice

    PubMed Central

    van Dijk, Theo H.; Havinga, Rick; van der Zee, Eddy A.; Groen, Albert K.; Reijngoud, Dirk-Jan; Bakker, Barbara M.; van Dijk, Gertjan

    2016-01-01

    At old age, humans generally have declining muscle mass and increased fat deposition, which can increase the risk of developing cardiometabolic diseases. While regular physical activity postpones these age-related derangements, this is not always possible in the elderly because of disabilities or risk of injury. Whole-body vibration (WBV) training may be considered as an alternative to physical activity particularly in the frail population. To explore this possibility, we characterized whole-body and organ-specific metabolic processes in 6-month and 25-month old mice, over a period of 14 weeks of WBV versus sham training. WBV training tended to increase blood glucose turnover rates and stimulated hepatic glycogen utilization during fasting irrespective of age. WBV was effective in reducing white fat mass and hepatic triglyceride content only in old but not in young mice and these reductions were related to upregulation of hepatic mitochondrial uncoupling of metabolism (assessed by high-resolution respirometry) and increased expression of uncoupling protein 2. Because these changes occurred independent of changes in food intake and whole-body metabolic rate (assessed by indirect calorimetry), the liver-specific effects of WBV may be a primary mechanism to improve metabolic health during aging, rather than that it is a consequence of alterations in energy balance. PMID:26886917

  14. Whole-Body Vibration Partially Reverses Aging-Induced Increases in Visceral Adiposity and Hepatic Lipid Storage in Mice.

    PubMed

    Reijne, Aaffien C; Ciapaite, Jolita; van Dijk, Theo H; Havinga, Rick; van der Zee, Eddy A; Groen, Albert K; Reijngoud, Dirk-Jan; Bakker, Barbara M; van Dijk, Gertjan

    2016-01-01

    At old age, humans generally have declining muscle mass and increased fat deposition, which can increase the risk of developing cardiometabolic diseases. While regular physical activity postpones these age-related derangements, this is not always possible in the elderly because of disabilities or risk of injury. Whole-body vibration (WBV) training may be considered as an alternative to physical activity particularly in the frail population. To explore this possibility, we characterized whole-body and organ-specific metabolic processes in 6-month and 25-month old mice, over a period of 14 weeks of WBV versus sham training. WBV training tended to increase blood glucose turnover rates and stimulated hepatic glycogen utilization during fasting irrespective of age. WBV was effective in reducing white fat mass and hepatic triglyceride content only in old but not in young mice and these reductions were related to upregulation of hepatic mitochondrial uncoupling of metabolism (assessed by high-resolution respirometry) and increased expression of uncoupling protein 2. Because these changes occurred independent of changes in food intake and whole-body metabolic rate (assessed by indirect calorimetry), the liver-specific effects of WBV may be a primary mechanism to improve metabolic health during aging, rather than that it is a consequence of alterations in energy balance. PMID:26886917

  15. Neonatal exposure to whole body ionizing radiation induces adult neurobehavioural defects: Critical period, dose--response effects and strain and sex comparison.

    PubMed

    Eriksson, Per; Buratovic, Sonja; Fredriksson, Anders; Stenerlöw, Bo; Sundell-Bergman, Synnöve

    2016-05-01

    Development of the brain includes periods which can be critical for its normal maturation. The present study investigates specifically vulnerable peri-/postnatal periods in mice which are essential for understanding the etiology behind radiation induced neurotoxicity and functional defects, including evaluation of neurotoxicity between sexes or commonly used laboratory mouse strains following low/moderate doses of ionizing radiation (IR). Male Naval Medical Research Institute (NMRI) mice, whole body irradiated to a single 500 mGy IR dose, on postnatal day (PND) 3 or PND 10 showed an altered adult spontaneous behaviour and impaired habituation capacity, whereas irradiation on PND 19 did not have any impact on the studied variables. Both NMRI and C57bl/6 male and female mice showed an altered adult spontaneous behaviour and impaired habituation following a single whole body irradiation of 500 or 1000 mGy, but not after 20 or 100 mGy, on PND 10. The present study shows that exposure to low/moderate doses of IR during critical life stages might be involved in the induction of neurological/neurodegenerative disorder/disease. A specifically vulnerable period for radiation induced neurotoxicity seems to be around PND 3-10 in mice. Further studies are needed to investigate mechanisms involved in induction of developmental neurotoxicity following low-dose irradiation. PMID:26876140

  16. Pegylated G-CSF Inhibits Blood Cell Depletion, Increases Platelets, Blocks Splenomegaly, and Improves Survival after Whole-Body Ionizing Irradiation but Not after Irradiation Combined with Burn

    PubMed Central

    Kiang, Juliann G.; Zhai, Min; Liao, Pei-Jyun; Bolduc, David L.; Elliott, Thomas B.; Gorbunov, Nikolai V.

    2014-01-01

    Exposure to ionizing radiation alone (radiation injury, RI) or combined with traumatic tissue injury (radiation combined injury, CI) is a crucial life-threatening factor in nuclear and radiological accidents. As demonstrated in animal models, CI results in greater mortality than RI. In our laboratory, we found that B6D2F1/J female mice exposed to 60Co-γ-photon radiation followed by 15% total-body-surface-area skin burns experienced an increment of 18% higher mortality over a 30-day observation period compared to irradiation alone; that was accompanied by severe cytopenia, thrombopenia, erythropenia, and anemia. At the 30th day after injury, neutrophils, lymphocytes, and platelets still remained very low in surviving RI and CI mice. In contrast, their RBC, hemoglobin, and hematocrit were similar to basal levels. Comparing CI and RI mice, only RI induced splenomegaly. Both RI and CI resulted in bone marrow cell depletion. It was observed that only the RI mice treated with pegylated G-CSF after RI resulted in 100% survival over the 30-day period, and pegylated G-CSF mitigated RI-induced body-weight loss and depletion of WBC and platelets. Peg-G-CSF treatment sustained RBC balance, hemoglobin levels, and hematocrits and inhibited splenomegaly after RI. The results suggest that pegylated G-CSF effectively sustained animal survival by mitigating radiation-induced cytopenia, thrombopenia, erythropenia, and anemia. PMID:24738019

  17. Pegylated G-CSF inhibits blood cell depletion, increases platelets, blocks splenomegaly, and improves survival after whole-body ionizing irradiation but not after irradiation combined with burn.

    PubMed

    Kiang, Juliann G; Zhai, Min; Liao, Pei-Jyun; Bolduc, David L; Elliott, Thomas B; Gorbunov, Nikolai V

    2014-01-01

    Exposure to ionizing radiation alone (radiation injury, RI) or combined with traumatic tissue injury (radiation combined injury, CI) is a crucial life-threatening factor in nuclear and radiological accidents. As demonstrated in animal models, CI results in greater mortality than RI. In our laboratory, we found that B6D2F1/J female mice exposed to (60)Co-γ-photon radiation followed by 15% total-body-surface-area skin burns experienced an increment of 18% higher mortality over a 30-day observation period compared to irradiation alone; that was accompanied by severe cytopenia, thrombopenia, erythropenia, and anemia. At the 30th day after injury, neutrophils, lymphocytes, and platelets still remained very low in surviving RI and CI mice. In contrast, their RBC, hemoglobin, and hematocrit were similar to basal levels. Comparing CI and RI mice, only RI induced splenomegaly. Both RI and CI resulted in bone marrow cell depletion. It was observed that only the RI mice treated with pegylated G-CSF after RI resulted in 100% survival over the 30-day period, and pegylated G-CSF mitigated RI-induced body-weight loss and depletion of WBC and platelets. Peg-G-CSF treatment sustained RBC balance, hemoglobin levels, and hematocrits and inhibited splenomegaly after RI. The results suggest that pegylated G-CSF effectively sustained animal survival by mitigating radiation-induced cytopenia, thrombopenia, erythropenia, and anemia. PMID:24738019

  18. Ghrelin Therapy Improves Survival after Whole-Body Ionizing Irradiation or Combined with Burn or Wound: Amelioration of Leukocytopenia, Thrombocytopenia, Splenomegaly, and Bone Marrow Injury

    PubMed Central

    Kiang, Juliann G.; Zhai, Min; Liao, Pei-Jyun; Elliott, Thomas B.; Gorbunov, Nikolai V.

    2014-01-01

    Exposure to ionizing radiation alone (RI) or combined with traumatic tissue injury (CI) is a crucial life-threatening factor in nuclear and radiological events. In our laboratory, mice exposed to 60Co-γ-photon radiation (9.5 Gy, 0.4 Gy/min, bilateral) followed by 15% total-body-surface-area skin wounds (R-W CI) or burns (R-B CI) experienced an increment of ≥18% higher mortality over a 30-day observation period compared to RI alone. CI was accompanied by severe leukocytopenia, thrombocytopenia, erythropenia, and anemia. At the 30th day after injury, numbers of WBC and platelets still remained very low in surviving RI and CI mice. In contrast, their RBC, hemoglobin, and hematocrit were recovered towards preirradiation levels. Only RI induced splenomegaly. RI and CI resulted in bone-marrow cell depletion. In R-W CI mice, ghrelin (a hunger-stimulating peptide) therapy increased survival, mitigated body-weight loss, accelerated wound healing, and increased hematocrit. In R-B CI mice, ghrelin therapy increased survival and numbers of neutrophils, lymphocytes, and platelets and ameliorated bone-marrow cell depletion. In RI mice, this treatment increased survival, hemoglobin, and hematocrit and inhibited splenomegaly. Our novel results are the first to suggest that ghrelin therapy effectively improved survival by mitigating CI-induced leukocytopenia, thrombocytopenia, and bone-marrow injury or the RI-induced decreased hemoglobin and hematocrit. PMID:25374650

  19. Effects of Surface Recombination on Heat Transfer to Bodies in a High Enthalpy Stream of Partially Dissociated Nitrogen

    NASA Technical Reports Server (NTRS)

    Winkler, Ernest L..; Griffin, Roy N., Jr.

    1961-01-01

    Heat-transfer rates to two surfaces having widely different catalytic effectiveness are compared at a Mach number of 6 in a low-density stream of partially dissociated nitrogen. The heat-transfer rate to a polished copper cylinder is twice as great as the heat-transfer rate to a silicon-monoxide-coated cylinder when the stream total energy content is 9000 Btu/lb. Various methods for determining the stream energy content, the stream velocity, and the stream Mach number have been developed and compared. It is shown that methods for estimating the stream energy content by means of purely aerodynamic concepts may neglect the sizable fraction of the stream energy contained in molecular dissociation.

  20. Angular momentum and orientation effects in excitation-ionization collisions

    NASA Astrophysics Data System (ADS)

    Harris, A. L.; Esposito, T. P.

    2016-08-01

    We present theoretical fully differential cross sections (FDCS) for electron-impact excitation-ionization of helium in which the final state He+ ion is oriented in a particular direction. Specifically, we study the process for He+ ions in the 2p0 state. Using our 4-body distorted wave model, we show a strong dependence of the FDCS on the ion’s orientation and trace some unexpected structures in the FDCS to the L = 2 term in the partial wave expansion for the ionized electron. A comparison is drawn to the ionization of oriented Mg (3p0) atoms, and unlike that process, we find that for excitation-ionization angular momentum must be transferred from either the projectile or the target atom.

  1. Desorption electrospray ionization mass spectrometry analysis of lipids after two-dimensional high-performance thin-layer chromatography partial separation

    PubMed Central

    Paglia, Giuseppe; Ifa, Demian R.; Wu, Chunping; Corso, Gaetano; Cooks, R. Graham

    2010-01-01

    Molecular imaging of separate but still incompletely resolved spots on high-performance thin-layer chromatography (HPTLC) plates is used for the direct analysis of porcine brain lipids by desorption electrospray ionization mass spectrometry (DESI-MS). Seven class-specific spots were imaged in the negative ion mode and shown to contain more than fifty lipids. A low lateral resolution of 400 × 400 μm allowed simple, rapid and incomplete separation to be combined with DESI imaging for the identification of many components of these extremely complex mixtures. In this work, tandem mass spectrometry (MS/MS) was also employed to confirm the identity of particular lipids directly on HPTLC plates. PMID:20128616

  2. Purification and partial genome characterization of the bacterial endosymbiont Blattabacterium cuenoti from the fat bodies of cockroaches

    PubMed Central

    Tokuda, Gaku; Lo, Nathan; Takase, Aya; Yamada, Akinori; Hayashi, Yoshinobu; Watanabe, Hirofumi

    2008-01-01

    Background Symbiotic relationships between intracellular bacteria and eukaryotes are widespread in nature. Genome sequencing of the bacterial partner has provided a number of key insights into the basis of these symbioses. A challenging aspect of sequencing symbiont genomes is separating the bacteria from the host tissues. In the present study, we describe a simple method of endosymbiont purification from complex environment, using Blattabacterium cuenoti inhabiting in cockroaches as a model system. Findings B. cuenoti cells were successfully purified from the fat bodies of the cockroach Panesthia angustipennis by a combination of slow- and fast-speed centrifugal fractionations, nylon-membrane filtration, and centrifugation with Percoll solutions. We performed pulse-field electrophoresis, diagnostic PCR and random sequencing of the shoutgun library. These experiments confirmed minimal contamination of host and mitochondrial DNA. The genome size and the G+C content of B. cuenoti were inferred to be 650 kb and 32.1 ± 7.6%, respectively. Conclusion The present study showed successful purification and characterization of the genome of B. cuenoti. Our methodology should be applicable for future symbiont genome sequencing projects. An advantage of the present purification method is that each step is easily performed with ordinary microtubes and a microcentrifuge, and without DNase treatment. PMID:19025664

  3. Energy of the ground and 2{sup +} excited states of {sub {lambda}}{sub {lambda}}{sup 10}Be: A partial ten-body model

    SciTech Connect

    Shoeb, Mohammad; Sonika

    2009-08-15

    The energies of the ground and excited 2{sup +} states of {sub {lambda}}{sub {lambda}}{sup 10}Be have been calculated variationally in the Monte Carlo framework. The hypernucleus is treated as a partial ten-body problem in the {lambda}{lambda}+{alpha}{alpha} model where nucleonic degrees of freedom of {alpha}'s are taken into consideration ignoring the antisymmetrization between two {alpha}'s. The central two-body {lambda}N and {lambda}{lambda} and the three-body dispersive and two-pion exchange {lambda}NN forces, constrained by the {lambda}p scattering data and the observed ground state energies of {sub {lambda}}{sup 5}He and {sub {lambda}}{sub {lambda}}{sup 6}He, are employed. The product-type trial wave function predicts binding energy for the ground state considerably less than for the event reported by Danysz et al.; however, it is consistent with the value deduced assuming a {gamma} ray of 3.04 MeV must have escaped undetected in the decay of the product {sub {lambda}}{sup 9}Be* {yields} {sub {lambda}}{sup 9}Be+{gamma} of the emulsion event {sub {lambda}}{sub {lambda}}{sup 10}Be{yields} {pi}{sup -}+p+{sub {lambda}}{sup 9}Be* and for the excited 2{sup +} state closer to the value measured in the Demachi-Yanagi event. The hypernucleus {sub {lambda}}{sub {lambda}}{sup 10}Be has an oblate shape in the excited state. These results are consistent with the earlier four-body {alpha} cluster model approach where {alpha}'s are assumed to be structureless entities.

  4. Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke

    PubMed Central

    Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

    2015-01-01

    [Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke. PMID:26157272

  5. Captopril Increases Survival after Whole-Body Ionizing Irradiation but Decreases Survival when Combined with Skin-Burn Trauma in Mice.

    PubMed

    Islam, Aminul; Bolduc, David L; Zhai, Min; Kiang, Juliann G; Swift, Joshua M

    2015-09-01

    Past and recent radiation events have involved a high incidence of radiation combined injury where victims often succumb to serious infections as a consequence of bacterial translocation and subsequent sepsis. The risk of infection is exacerbated in radiation combined skin-burn injury (RCI), which increase vulnerability. Furthermore, no suitable countermeasures for radiation combined skin-burn injury have been established. In this study, we evaluated captopril as a potential countermeasure to radiation combined skin-burn injury. Captopril is an FDA-approved angiotensin-converting enzyme inhibitor that was previously reported to stimulate hematopoietic recovery after exposure to ionizing radiation. Female B6D2F1/J mice were whole-body bilateral (60)Co gamma-photon irradiated (dose rate of 0.4 Gy/min) with 9.5 Gy (LD70/30 for RCI), followed by nonlethal dorsal skin-burn injury under anesthesia (approximately 15% total-body surface-area burn). Mice were provided with acidified drinking water with or without dissolved captopril (0.55 g/l) for 30 days immediately after injury and were administered topical gentamicin (0.1% cream; day 1-10) and oral levofloxacin (90-100 mg/kg; day 3-16). Surviving mice were euthanized on day 30 after analyses of water consumption, body weight and survival. Our data demonstrate that, while treatment with captopril did mitigate mortality induced by radiation injury (RI) alone (55% captopril vs. 80% vehicle; n = 20, P < 0.05), it also resulted in decreased survival after radiation combined skin-burn injury (22% captopril vs. 41% vehicle; n = 22, P < 0.05). Moreover, captopril administration via drinking water produced an uneven dosage pattern among the different injury groups ranging from 74 ± 5.4 to 115 ± 2.2 mg/kg/day. Captopril treatment also did not counteract the negative alterations in hematology, splenocytes or bone marrow cellularity after either radiation injury or radiation combined skin-burn injury. These data suggest that

  6. THE PROLONGED GASTROINTESTINAL SYNDROME IN RHESUS MACAQUES: THE RELATIONSHIP BETWEEN GASTROINTESTINAL, HEMATOPOIETIC, AND DELAYED MULTI-ORGAN SEQUELAE FOLLOWING ACUTE, POTENTIALLY LETHAL, PARTIAL-BODY IRRADIATION

    PubMed Central

    MacVittie, Thomas J.; Bennett, Alexander; Booth, Catherine; Garofalo, Michael; Tudor, Gregory; Ward, Amanda; Shea-Donohue, Terez; Gelfond, Daniel; McFarland, Emylee; Jackson, William; Lu, Wei; Farese, Ann M.

    2014-01-01

    The dose response relationship for the acute gastrointestinal syndrome following total-body irradiation prevents analysis of the full recovery and damage to the gastrointestinal system, since all animals succumb to the subsequent 100% lethal hematopoietic syndrome. A partial-body irradiation model with 5% bone marrow sparing was established to investigate the prolonged effects of high-dose radiation on the gastrointestinal system, as well as the concomitant hematopoietic syndrome and other multi-organ injury including the lung. Herein, cellular and clinical parameters link acute and delayed coincident sequelae to radiation dose and time course post-exposure. Male rhesus Macaca mulatta were exposed to partial-body irradiation with 5% bone marrow (tibiae, ankles, feet) sparing using 6 MV linear accelerator photons at a dose rate of 0.80 Gy min−1 to midline tissue (thorax) doses in the exposure range of 9.0 to 12.5 Gy. Following irradiation, all animals were monitored for multiple organ-specific parameters for 180 d. Animals were administered medical management including administration of intravenous fluids, antiemetics, prophylactic antibiotics, blood transfusions, antidiarrheals, supplemental nutrition, and analgesics. The primary endpoint was survival at 15, 60, or 180 d post-exposure. Secondary endpoints included evaluation of dehydration, diarrhea, hematologic parameters, respiratory distress, histology of small and large intestine, lung radiographs, and mean survival time of decedents. Dose- and time-dependent mortality defined several organ-specific sequelae, with LD50/15 of 11.95 Gy, LD50/60 of 11.01 Gy, and LD50/180 of 9.73 Gy for respective acute gastrointestinal, combined hematopoietic and gastrointestinal, and multi-organ delayed injury to include the lung. This model allows analysis of concomitant multi-organ sequelae, thus providing a link between acute and delayed radiation effects. Specific and multi-organ medical countermeasures can be assessed for

  7. Origin of felsic achondrites Graves Nunataks 06128 and 06129, and ultramafic brachinites and brachinite-like achondrites by partial melting of volatile-rich primitive parent bodies

    NASA Astrophysics Data System (ADS)

    Day, James M. D.; Walker, Richard J.; Ash, Richard D.; Liu, Yang; Rumble, Douglas; Irving, Anthony J.; Goodrich, Cyrena A.; Tait, Kimberly; McDonough, William F.; Taylor, Lawrence A.

    2012-03-01

    New major- and trace-element abundances, highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re) abundances, and oxygen and rhenium-osmium isotope data are reported for oligoclase-rich meteorites Graves Nunataks 06128 and 06129 (GRA 06128/9), six brachinites (Brachina; Elephant Morraine 99402/7; Northwest Africa (NWA) 1500; NWA 3151; NWA 4872; NWA 4882) and three olivine-rich achondrites, which are referred to here as brachinite-like achondrites (NWA 5400; NWA 6077; Zag (b)). GRA 06128/9 represent examples of felsic and highly-sodic melt products from an asteroid that may provide a differentiation complement to brachinites and/or brachinite-like achondrites. The new data, together with our petrological observations, are consistent with derivation of GRA 06128/9, brachinites and the three brachinite-like achondrites from nominally volatile-rich and oxidised 'chondritic' precursor sources within their respective parent bodies. Furthermore, the range of Δ17O values (˜0‰ to -0.3‰) among the meteorites indicates generation from isotopically heterogeneous sources that never completely melted, or isotopically homogenised. It is possible to generate major- and trace-element compositions similar to brachinites and the three studied brachinite-like achondrites as residues of moderate degrees (13-30%) of partial melting of primitive chondritic sources. This process was coupled with inefficient removal of silica-saturated, high Fe/Mg felsic melts with compositions similar to GRA 06128/9. Melting of the parent bodies of GRA 06128/9, brachinites and brachinite-like achondrites halted well before extensive differentiation, possibly due to the exhaustion of the short-lived radionuclide 26Al by felsic melt segregation. This mechanism provides a potential explanation for the cessation of run-away melting in asteroids to preserve achondrites such as GRA 06128/9, brachinites, brachinite-like achondrites, acapulcoite-lodranites, ureilites and aubrites. Moderate degrees of

  8. Calcium - ionized

    MedlinePlus

    ... at both ionized calcium and calcium attached to proteins. You may need to have a separate ionized calcium test if you have factors that increase or decrease total calcium levels. These may include abnormal blood levels ...

  9. Analytical instruments, ionization sources, and ionization methods

    DOEpatents

    Atkinson, David A.; Mottishaw, Paul

    2006-04-11

    Methods and apparatus for simultaneous vaporization and ionization of a sample in a spectrometer prior to introducing the sample into the drift tube of the analyzer are disclosed. The apparatus includes a vaporization/ionization source having an electrically conductive conduit configured to receive sample particulate which is conveyed to a discharge end of the conduit. Positioned proximate to the discharge end of the conduit is an electrically conductive reference device. The conduit and the reference device act as electrodes and have an electrical potential maintained between them sufficient to cause a corona effect, which will cause at least partial simultaneous ionization and vaporization of the sample particulate. The electrical potential can be maintained to establish a continuous corona, or can be held slightly below the breakdown potential such that arrival of particulate at the point of proximity of the electrodes disrupts the potential, causing arcing and the corona effect. The electrical potential can also be varied to cause periodic arcing between the electrodes such that particulate passing through the arc is simultaneously vaporized and ionized. The invention further includes a spectrometer containing the source. The invention is particularly useful for ion mobility spectrometers and atmospheric pressure ionization mass spectrometers.

  10. Partially Hydrolyzed Guar Gum in the Treatment of Irritable Bowel Syndrome with Constipation: Effects of Gender, Age, and Body Mass Index

    PubMed Central

    Russo, Luigi; Andreozzi, Paolo; Zito, Francesco P.; Vozzella, Letizia; Savino, Ivana G.; Sarnelli, Giovanni; Cuomo, Rosario

    2015-01-01

    Background/Aims: Partially hydrolyzed guar gum (PHGG) relieves symptoms in constipation-predominant irritable bowel syndrome (IBS) and may have prebiotic properties. However, the correlation between the effectiveness of PHGG and patient characteristics has not been examined. We aimed to investigate the effect of PHGG in symptom relief on constipation-predominant IBS according to gender, age, and body mass index (BMI). Patients and Methods: Sixty-eight patients with IBS entered a 2-week run-in period, followed by a 4-week study period with PHGG. Patients completed a daily questionnaire to assess the presence of abdominal pain/discomfort, swelling, and the sensation of incomplete evacuation. The number of evacuations/day, the daily need for laxatives/enemas and stool consistency-form were also evaluated. All patients also underwent a colonic transit time (CTT) evaluation. Results: PHGG administration was associated with a significant improvement in symptom scores, use of laxatives/enemas, stool form/consistency and CTT. At the end of the study period and compared with baseline, the number of evacuations improved in women, patients aged ≥ 45 years and those with BMI ≥ 25 (P < 0.05 for all comparisons); abdominal bloating improved in males (P < 0.05), patients < 45 years (P < 0.01) and those with BMI < 25 (P < 0.05). A decrease in the number of perceived incomplete evacuations/day was reported in patients with a BMI ≥ 25 (P < 0.05). Reductions in laxative/enema use were recorded in females (P < 0.05), patients < 45 years (P < 0.01), and patients with BMI < 25 (P < 0.05). Conclusions: Gender, age, and BMI seem to influence the effect of PHGG supplementation in constipated IBS patients. Further studies are needed to clarify the interaction of such parameters with a fiber-enriched diet. PMID:25843197

  11. Improvement of registration accuracy in accelerated partial breast irradiation using the point-based rigid-body registration algorithm for patients with implanted fiducial markers

    SciTech Connect

    Inoue, Minoru; Yoshimura, Michio Sato, Sayaka; Nakamura, Mitsuhiro; Yamada, Masahiro; Hirata, Kimiko; Ogura, Masakazu; Hiraoka, Masahiro; Sasaki, Makoto; Fujimoto, Takahiro

    2015-04-15

    Purpose: To investigate image-registration errors when using fiducial markers with a manual method and the point-based rigid-body registration (PRBR) algorithm in accelerated partial breast irradiation (APBI) patients, with accompanying fiducial deviations. Methods: Twenty-two consecutive patients were enrolled in a prospective trial examining 10-fraction APBI. Titanium clips were implanted intraoperatively around the seroma in all patients. For image-registration, the positions of the clips in daily kV x-ray images were matched to those in the planning digitally reconstructed radiographs. Fiducial and gravity registration errors (FREs and GREs, respectively), representing resulting misalignments of the edge and center of the target, respectively, were compared between the manual and algorithm-based methods. Results: In total, 218 fractions were evaluated. Although the mean FRE/GRE values for the manual and algorithm-based methods were within 3 mm (2.3/1.7 and 1.3/0.4 mm, respectively), the percentages of fractions where FRE/GRE exceeded 3 mm using the manual and algorithm-based methods were 18.8%/7.3% and 0%/0%, respectively. Manual registration resulted in 18.6% of patients with fractions of FRE/GRE exceeding 5 mm. The patients with larger clip deviation had significantly more fractions showing large FRE/GRE using manual registration. Conclusions: For image-registration using fiducial markers in APBI, the manual registration results in more fractions with considerable registration error due to loss of fiducial objectivity resulting from their deviation. The authors recommend the PRBR algorithm as a safe and effective strategy for accurate, image-guided registration and PTV margin reduction.

  12. Ionizing radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter gives a comprehensive review on ionizing irradiation of fresh fruits and vegetables. Topics include principles of ionizing radiation, its effects on pathogenic and spoilage microorganisms, shelf-life, sensory quality, nutritional and phytochemical composition, as well as physiologic and...

  13. Ambient ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Lebedev, A. T.

    2015-07-01

    Ambient ionization mass spectrometry emerged as a new scientific discipline only about ten years ago. A considerable body of information has been reported since that time. Keeping the sensitivity, performance and informativity of classical mass spectrometry methods, the new approach made it possible to eliminate laborious sample preparation procedures and triggered the development of miniaturized instruments to work directly in the field. The review concerns the theoretical foundations and design of ambient ionization methods. Their advantages and drawbacks, as well as prospects for application in chemistry, biology, medicine, environmetal analysis, etc., are discussed. The bibliography includes 194 references.

  14. Magnetic solid phase extraction coupled with desorption corona beam ionization-mass spectrometry for rapid analysis of antidepressants in human body fluids.

    PubMed

    Chen, Di; Zheng, Hao-Bo; Huang, Yun-Qing; Hu, Yu-Ning; Yu, Qiong-Wei; Yuan, Bi-Feng; Feng, Yu-Qi

    2015-08-21

    Ambient ionization techniques show good potential in rapid analysis of target compounds. However, a direct application of these ambient ionization techniques for the determination of analytes in a complex matrix is difficult due to the matrix interference and ion suppression. To resolve this problem, here we developed a strategy by coupling magnetic solid phase extraction (MSPE) with desorption corona beam ionization (DCBI)-mass spectrometry (MS). As a proof of concept, the pyrrole-coated Fe3O4 magnetic nanoparticles (Fe3O4@Ppy) were prepared and used for the extraction of antidepressants. After extraction, the Fe3O4@Ppy with trapped antidepressants was then directly subjected to DCBI-MS analysis with the aid of a homemade magnetic glass capillary. As the MSPE process is rapid and the direct DCBI-MS analysis does not need solvent desorption or chromatographic separation processes, the overall analysis can be completed within 3 min. The proposed MSPE-DCBI-MS method was then successfully used to determine antidepressants in human urine and plasma. The calibration curves were obtained in the range of 0.005-0.5 μg mL(-1) for urine and 0.02-1 μg mL(-1) for plasma with reasonable linearity (R(2) > 0.951). The limits of detection of three antidepressants were in the range of 0.2-1 ng mL(-1) for urine and 2-5 ng mL(-1) for plasma. Acceptable reproducibility for rapid analysis was achieved with relative standard deviations less than 19.1% and the relative recoveries were 85.2-118.7%. Taken together, the developed MSPE-DCBI-MS strategy offers a powerful capacity for rapid analysis of target compounds in a complex matrix, which would greatly expand the applications of ambient ionization techniques with plentiful magnetic sorbents. PMID:26145704

  15. Dynamical orientation effects in atomic ionization by impact of protons and positrons

    NASA Astrophysics Data System (ADS)

    Fregenal, Daniel; Barrachina, Raúl; Bernardi, Guillermo; Suárez, Sergio; Fiol, Juan

    2011-10-01

    Recent results in ionization collisions with positrons and protons showed that just above the two-body threshold, for electron velocities close to the final projectile's velocity, the electron-projectile continuum dipole is narrowly oriented along the direction of motion of its centre-of-mass, with the negative charge pointing towards the residual target. Although a forward-backward asymmetry in the vicinity of the two-body threshold has been studied many year ago in ion impact ionization collisions, that was by far a much milder effect that left no fingerprint on the cusp position. Our results show that the phenomena is present for ionization by impact of both protons and positrons. In this communication, through measurements on H+ + He and calculations we analyze in detail this effect that can be linked to a dynamical alignment of the two-body subsystem in the continuum. Recent results in ionization collisions with positrons and protons showed that just above the two-body threshold, for electron velocities close to the final projectile's velocity, the electron-projectile continuum dipole is narrowly oriented along the direction of motion of its centre-of-mass, with the negative charge pointing towards the residual target. Although a forward-backward asymmetry in the vicinity of the two-body threshold has been studied many year ago in ion impact ionization collisions, that was by far a much milder effect that left no fingerprint on the cusp position. Our results show that the phenomena is present for ionization by impact of both protons and positrons. In this communication, through measurements on H+ + He and calculations we analyze in detail this effect that can be linked to a dynamical alignment of the two-body subsystem in the continuum. This work was partially supported by the Consejo Nacional de Investigaciones Cientificas y Tecnicas, Universidad Nacional de Cuyo and Fundacion Balseiro.

  16. Nuclear actin is partially associated with Cajal bodies in human cells in culture and relocates to the nuclear periphery after infection of cells by adenovirus 5

    SciTech Connect

    Gedge, L.J.E.; Morrison, E.E.; Blair, G.E.; Walker, J.H. . E-mail: J.H.Walker@leeds.ac.uk

    2005-02-15

    Cajal bodies are intra-nuclear structures enriched in proteins involved in transcription and mRNA processing. In this study, immunofluorescence microscopy experiments using a highly specific antibody to actin revealed nuclear actin spots that colocalized in part with p80 coilin-positive Cajal bodies. Actin remained associated with Cajal bodies in cells extracted to reveal the nuclear matrix. Adenovirus infection, which is known to disassemble Cajal bodies, resulted in loss of actin from these structures late in infection. In infected cells, nuclear actin was observed to relocate to structures at the periphery of the nucleus, inside the nuclear envelope. Based on these findings, it is suggested that actin may play an important role in the organization or function of the Cajal body.

  17. The role of hemoglobin heme loss in Heinz body formation: studies with a partially heme-deficient hemoglobin and with genetically unstable hemoglobins

    PubMed Central

    Jacob, Harry S.; Winterhalter, Kaspar H.

    1970-01-01

    A number of mutant hemoglobins are inordinately unstable, denaturing in circulating red cells into Heinz bodies, resulting in congenital Heinz body hemolytic anemia (CHBHA). We have emphasized that most such hemoglobins involve amino acid substitutions at sites neighboring the heme group of the β-polypeptide chain, and have shown that heme binding to globin is diminished thereby. Thus, hemes were progressively lost from four unstable hemoglobins (Köln, Hammersmith, San Francisco, and Zürich) as they precipitated into Heinz bodies at 50°C. The role of heme loss, especially from beta chains, in Heinz body formation was supported by studies with a hemoglobin synthesized to contain hemes only on its alpha chains (α2hemeβ20). The behavior of this compound, postulated to be an intermediary in the formation of Heinz bodies, mimicked that of the genetically unstable hemoglobins in several ways: (a) it precipitated at 50°C into typical coccoid Heinz bodies; (b) as also observed with CHBHA hemoglobins this denaturation was virtually prevented by the heme ligands, cyanide or carbon monoxide, which inhibit further heme loss; it was potentiated by oxidation of hemes to the ferri- state, which accentuates heme loss; (c) the thiol groups of α2hemeβ20 were hyperreactive, forming mixed disulfides with glutathione and membrane sulfhydryls at rates similar to those of CHBHA hemoglobins and 10 or more times that of normal hemoglobin A; (d) heme repletion of the protein molecules by the addition of crystalline hemin to either α2hemeβ20 or to the genetically unstable hemoglobins, prevented their precipitation into Heinz bodies and normalized their aberrant electrophoretic behaviors; and (e) during Heinz body formation at 50°C both α2hemeβ20 and the genetically unstable hemoglobins released free αheme-chains into solution, suggesting that the bulk of the whitish, Heinz body precipitate is naked β8-chains. We conclude that heme loss from mutant beta chains is an early step

  18. Identification of cysteinylated transthyretin, a predictive biomarker of treatment response to partially hydrolyzed guar gum in type 2 diabetes rats, by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry.

    PubMed

    Naito, Yuji; Ichikawa, Hiroshi; Akagiri, Satomi; Uchiyama, Kazuhiko; Takagi, Tomohisa; Handa, Osamu; Yasukawa, Zenta; Tokunaga, Makoto; Ishihara, Noriyuki; Okubo, Tsutomu; Mukai, Jun; Ohki, Makoto; Uchida, Kagehiro; Yoshikawa, Toshikazu

    2016-01-01

    Recent evidence has indicated that total fiber intake is inversely related to type 2 diabetes risk. The present study aimed to investigate the effects of chronic administration of partially hydrolyzed guar gum (PHGG), a water-soluble dietary fiber, on the occurrence of diabetes and its complications, fatty liver and nephropathy. We also identified predictive serum biomarkers of treatment response to PHGG by mass spectroscopy-based proteomic analysis using Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a good model of human non-insulin-dependent diabetes mellitus. In this study, at 5 weeks of age, OLETF rats and control strain Long-Evans Tokushima Otsuka (LETO) rats were fed a control diet or a high-fiber diet (5% PHGG) for 57 weeks. Body weight, food intake, oral glucose tolerance test, plasma insulin levels, and urine glucose and protein levels were regularly measured. Oral glucose tolerance tests (OGTT) and storage of serum in a deep freezer were conducted at the beginning of the experiment and every 4 weeks after overnight fasting during the experiments. PHGG treatment affected neither meal patterns nor the body weight of OLETF and LETO rats. Repeated measure analysis of variance revealed significant differences in fasting plasma glucose and plasma glucose at 2 h after OGTT between control OLETF (OLETF-C) rats and OLETF rats treated with PHGG (OLETF-F). The glucose response determined by the area under the curve of OGTT was significantly greater in OLETF-C rats than that in OLETF-F rats at 25 weeks of age. HOMA-IR, an index of insulin resistance, increased at 25 weeks of age in OLETF-C rats, while this increase was significantly inhibited in OLETF-F rats. At 62 weeks of age, PHGG treatment significantly improved hepatic steatosis as well as renal mesangial matrix accumulation in OLETF rats. To identify the risk marker for diabetes mellitus by SELDI-TOF MS, we collected sera from 21-week-old individuals. Among the 12 specific peaks that were risk marker

  19. Identification of cysteinylated transthyretin, a predictive biomarker of treatment response to partially hydrolyzed guar gum in type 2 diabetes rats, by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry

    PubMed Central

    Naito, Yuji; Ichikawa, Hiroshi; Akagiri, Satomi; Uchiyama, Kazuhiko; Takagi, Tomohisa; Handa, Osamu; Yasukawa, Zenta; Tokunaga, Makoto; Ishihara, Noriyuki; Okubo, Tsutomu; Mukai, Jun; Ohki, Makoto; Uchida, Kagehiro; Yoshikawa, Toshikazu

    2016-01-01

    Recent evidence has indicated that total fiber intake is inversely related to type 2 diabetes risk. The present study aimed to investigate the effects of chronic administration of partially hydrolyzed guar gum (PHGG), a water-soluble dietary fiber, on the occurrence of diabetes and its complications, fatty liver and nephropathy. We also identified predictive serum biomarkers of treatment response to PHGG by mass spectroscopy-based proteomic analysis using Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a good model of human non-insulin-dependent diabetes mellitus. In this study, at 5 weeks of age, OLETF rats and control strain Long-Evans Tokushima Otsuka (LETO) rats were fed a control diet or a high-fiber diet (5% PHGG) for 57 weeks. Body weight, food intake, oral glucose tolerance test, plasma insulin levels, and urine glucose and protein levels were regularly measured. Oral glucose tolerance tests (OGTT) and storage of serum in a deep freezer were conducted at the beginning of the experiment and every 4 weeks after overnight fasting during the experiments. PHGG treatment affected neither meal patterns nor the body weight of OLETF and LETO rats. Repeated measure analysis of variance revealed significant differences in fasting plasma glucose and plasma glucose at 2 h after OGTT between control OLETF (OLETF-C) rats and OLETF rats treated with PHGG (OLETF-F). The glucose response determined by the area under the curve of OGTT was significantly greater in OLETF-C rats than that in OLETF-F rats at 25 weeks of age. HOMA-IR, an index of insulin resistance, increased at 25 weeks of age in OLETF-C rats, while this increase was significantly inhibited in OLETF-F rats. At 62 weeks of age, PHGG treatment significantly improved hepatic steatosis as well as renal mesangial matrix accumulation in OLETF rats. To identify the risk marker for diabetes mellitus by SELDI-TOF MS, we collected sera from 21-week-old individuals. Among the 12 specific peaks that were risk marker

  20. Laser induced avalanche ionization in gases or gas mixtures with resonantly enhanced multiphoton ionization or femtosecond laser pulse pre-ionization

    SciTech Connect

    Shneider, Mikhail N.; Miles, Richard B.

    2012-08-15

    The paper discusses the requirements for avalanche ionization in gas or gas mixtures initiated by REMPI or femtosecond-laser pre-ionization. Numerical examples of dependencies on partial composition for Ar:Xe gas mixture with REMPI of argon and subsequent classic avalanche ionization of Xe are presented.

  1. Ionization chamber

    DOEpatents

    Walenta, Albert H.

    1981-01-01

    An ionization chamber has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionize the gas.

  2. Ionization chamber

    DOEpatents

    Walenta, A.H.

    An ionization chamber is described which has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionizes the gas.

  3. IONIZATION CHAMBER

    DOEpatents

    Redman, W.C.; Shonka, F.R.

    1958-02-18

    This patent describes a novel ionization chamber which is well suited to measuring the radioactivity of the various portions of a wire as the wire is moved at a uniform speed, in order to produce the neutron flux traverse pattern of a reactor in which the wire was previously exposed to neutron radiation. The ionization chamber of the present invention is characterized by the construction wherein the wire is passed through a tubular, straight electrode and radiation shielding material is disposed along the wire except at an intermediate, narrow area where the second electrode of the chamber is located.

  4. Understanding Ti intermediate-band formation in partially inverse thiospinel MgIn2S4 through many-body approaches

    NASA Astrophysics Data System (ADS)

    Aguilera, I.; Palacios, Pablo; Wahnón, P.

    2011-09-01

    Indium atoms in octahedral sites are substituted by Ti atoms in spinel MgIn2S4, where d states of Ti form an intermediate band. However, the complex spinel structure of the host semiconductor requires a supercell study of the intermediate-band compound. Self-consistent many-body approaches are applied to the smaller cell of this material, starting from the static Coulomb-hole and screened-exchange approximation to the GW approach and then carrying out a perturbative GW calculation. We discuss the influence of many-body effects on the formation of the intermediate band through a comparison with density functional theory (DFT) and DFT+U. We find that both the self-consistent parameter-free many-body and DFT+U+G0W0 calculations indicate that only a totally occupied intermediate band can be formed by Ti in inverse MgIn2S4. This justifies the use of DFT+U+G0W0 to treat the supercells, when the self-consistent GW is not affordable.

  5. Simultaneous resonant enhanced multiphoton ionization and electron avalanche ionization in gas mixtures

    SciTech Connect

    Shneider, Mikhail N.; Zhang Zhili; Miles, Richard B.

    2008-07-15

    Resonant enhanced multiphoton ionization (REMPI) and electron avalanche ionization (EAI) are measured simultaneously in Ar:Xe mixtures at different partial pressures of mixture components. A simple theory for combined REMPI+EAI in gas mixture is developed. It is shown that the REMPI electrons seed the avalanche process, and thus the avalanche process amplifies the REMPI signal. Possible applications are discussed.

  6. Fluid hydrogen at high density - Pressure ionization

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1992-01-01

    The Helmholtz-free-energy model for nonideal mixtures of hydrogen atoms and molecules by Saumon and Chabrier (1991) is extended to describe dissociation and ionization in similar mixtures in chemical equilibrium. A free-energy model is given that describes partial ionization in the pressure and temperature ionization region. The plasma-phase transition predicted by the model is described for hydrogen mixtures including such components as H2, H, H(+), and e(-). The plasma-phase transition has a critical point at Tc = 15,300 K and Pc = 0.614 Mbar, and thermodynamic instability is noted in the pressure-ionization regime. The pressure dissociation and ionization of fluid hydrogen are described well with the model yielding information on the nature of the plasma-phase transition. The model is shown to be valuable for studying dissociation and ionization in astrophysical objects and in high-pressure studies where pressure and temperature effects are significant.

  7. Hand and shoe monitor using air ionization probes

    DOEpatents

    Fergus, Richard W.

    1981-01-01

    A hand and shoe radiation monitor is provided which includes a probe support body defining a plurality of cells, within each cell there being an ionization probe. The support body provides structural strength for protecting the ionization probes from force applied to the support body during a radiation monitoring event. There is also provided a fast response time amplifier circuit for the output from the ionization probes.

  8. Inhibition of gastric secretion in guinea pig by relatively low dose ionizing radiation

    SciTech Connect

    Batzri, S.; Catravas, G.

    1988-11-01

    We evaluated the effect of a single dose of ionizing radiation on gastric secretion in awake guinea pigs equipped with a permanent gastric cannula. Changes in gastric secretion were measured using a dye dilution technique. Infusion of histamine increased acid and fluid output and there was a positive correlation (r = 0.93) between the two. Total body irradiation with 400 cGy, like cimetidine, suppressed acid and fluid secretion under basal conditions and during histamine stimulation by 50-90%. Recovery from the radiation damage was only partial after one week. Irradiation inhibited the rise in gastric juice volume during histamine stimulation and also reduced the normal gain in body weight of the guinea pig. These results demonstrate that ionizing radiations have an immediate and long lasting effects on the gastric mucosal function of the guinea pig.

  9. Quality of life, reproduction and sexuality after stem cell transplantation with partially T-cell-depleted grafts and after conditioning with a regimen including total body irradiation.

    PubMed

    Claessens, J J M; Beerendonk, C C M; Schattenberg, A V M B

    2006-05-01

    Thirty-four men and 36 women (median age 43 and 45 years, respectively) underwent stem cell transplantation (SCT) for acute leukaemia in first complete remission or chronic myelogenous leukaemia in first chronic phase between 1981 and 2001 from HLA-identical siblings. The conditioning regimen included TBI and all grafts were partially depleted of T cells. Changes in quality of life (QOL), reproduction and sexuality were studied using a questionnaire, and the previously given information related to these problems was assessed. In addition, endocrine status was assessed and semen analysis was performed. After SCT, patients reported less energy (n=50) and a deterioration in the job situation (n=31). Patients experienced a negative change in sexual relations (n=41). Important problems of sexual dysfunction were vaginal dryness in women (n=19) and erectile dysfunction in men (n=16). None of the patients was fertile based on their gonadotrophin levels, sperm concentrations and reproductive outcomes. Women experienced climacteric symptoms (n=24). Quality of life was negatively influenced by these changes. One-fifth of the patients were not satisfied with the information given with regard to reproduction, premature menopause and sexual problems. PMID:16547485

  10. Liquid Microjunction Surface Sampling Coupled with High-Pressure Liquid Chromatography-Electrospray Ionization-Mass Spectrometry for Analysis of Drugs and Metabolites in Whole-Body Thin Tissue Sections

    SciTech Connect

    Kertesz, Vilmos; Van Berkel, Gary J

    2010-01-01

    In this work, a commercially available autosampler was adapted to perform direct liquid microjunction (LMJ) surface sampling followed by a high-pressure liquid chromatography (HPLC) separation of the extract components and detection with electrospray ionization mass spectrometry (ESI-MS). To illustrate the utility of coupling a separation with this direct liquid extraction based surface sampling approach, four different organs (brain, lung, kidney, and liver) from whole-body thin tissue sections of propranolol dosed and control mice were examined. The parent drug was observed in the chromatograms of the surface sampling extracts from all the organs of the dosed mouse examined. In addition, two isomeric phase II metabolites of propranolol (an aliphatic and an aromatic hydroxypropranolol glucuronide) were observed in the chromatograms of the extracts from lung, kidney, and liver. Confirming the presence of one or the other or both of these glucuronides in the extract from the various organs was not possible without the separation. These drug and metabolite data obtained using the LMJ surface sampling/HPLC-MS method and the results achieved by analyzing similar samples by conventional extraction of the tissues and subsequent HPLC-MS analysis were consistent.

  11. Partial Return Yoke for MICE

    SciTech Connect

    Witte H.; Plate, S

    2013-05-03

    The international Muon Ionization Cooling Experiment (MICE) is a large scale experiment which is presently assembled at the Rutherford Appleton Laboratory in Didcot, UK. The purpose of MICE is to demonstrate the concept of ionization cooling experimentally. Ionization cooling is an important accelerator concept which will be essential for future HEP experiments such as a potential Muon Collider or a Neutrino Factory. The MICE experiment will house up to 18 superconducting solenoids, all of which produce a substantial amount of magnetic flux. Recently it was realized that this magnetic flux leads to a considerable stray magnetic field in the MICE hall. This is a concern as technical equipment in the MICE hall may may be compromised by this. In July 2012 a concept called partial return yoke was presented to the MICE community, which reduces the stray field in the MICE hall to a safe level. This report summarizes the general concept, engineering considerations and the expected shielding performance.

  12. The Enhanced Role of Shallow-Trench Isolation in Ionizing Radiation Damage of Narrow Width Devices in 0.2 μm Partially-Depleted Silicon-on-Insulator Technology

    NASA Astrophysics Data System (ADS)

    Huang, Hui-Xiang; Bi, Da-Wei; Peng, Chao; Zhang, Yan-Wei; Zhang, Zheng-Xuan

    2013-08-01

    An anomalous total dose effect is observed in narrow-width devices fabricated in a 0.2 μm partially-depleted silicon-on-insulator (SOI) technology. The previous radiation-induced narrow channel effect manifests itself with obvious threshold voltage shift after the transistors are subjected to total dose radiation in bulk technology. Nevertheless, a sharply increasing off-state leakage current dominates the total dose effects in narrow devices of this partially-depleted SOI technology instead of threshold voltage shifts. A radiation-induced positive charge trapping model is introduced to understand this phenomenon. The enhanced role of shallow-trench oxide induced by compressive mechanical stress in narrow devices is discussed in detail in terms of modification of the edge impurity density and charge trapping characteristics, which affect the total dose sensitivity.

  13. Epilepsy (partial)

    PubMed Central

    2011-01-01

    Introduction About 3% of people will be diagnosed with epilepsy during their lifetime, but about 70% of people with epilepsy eventually go into remission. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of starting antiepileptic drug treatment following a single seizure? What are the effects of drug monotherapy in people with partial epilepsy? What are the effects of additional drug treatments in people with drug-resistant partial epilepsy? What is the risk of relapse in people in remission when withdrawing antiepileptic drugs? What are the effects of behavioural and psychological treatments for people with epilepsy? What are the effects of surgery in people with drug-resistant temporal lobe epilepsy? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 83 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiepileptic drugs after a single seizure; monotherapy for partial epilepsy using carbamazepine, gabapentin, lamotrigine, levetiracetam, phenobarbital, phenytoin, sodium valproate, or topiramate; addition of second-line drugs for drug-resistant partial epilepsy (allopurinol, eslicarbazepine, gabapentin, lacosamide, lamotrigine, levetiracetam, losigamone, oxcarbazepine, retigabine, tiagabine, topiramate, vigabatrin, or zonisamide); antiepileptic drug withdrawal for people with partial or

  14. Multiphoton ionization of Uracil

    NASA Astrophysics Data System (ADS)

    Prieto, Eladio; Martinez, Denhi; Guerrero, Alfonso; Alvarez, Ignacio; Cisneros, Carmen

    2016-05-01

    Multiphoton ionization and dissociation of Uracil using a Reflectron time of flight spectrometer was performed along with radiation from the second harmonic of a Nd:YAG laser. Uracil is one of the four nitrogen bases that belong to RNA. The last years special interest has been concentrated on the study of the effects under UV radiation in nucleic acids1 and also in the role that this molecule could have played in the origin and development of life on our planet.2 The MPI mass spectra show that the presence and intensity of the resulting ions strongly depend on the density power. The identification of the ions in the mass spectra is presented. The results are compared with those obtained in other laboratories under different experimental conditions and some of them show partial agreement.3 The present work was supported by CONACYT-Mexico Grant 165410 and DGAPA UNAM Grant IN101215 and IN102613.

  15. Weakly ionized cosmic gas: Ionization and characterization

    NASA Technical Reports Server (NTRS)

    Rosenberg, M.; Mendis, D. A.; Chow, V. W.

    1994-01-01

    Since collective plasma behavior may determine important transport processes (e.g., plasma diffusion across a magnetic field) in certain cosmic environments, it is important to delineate the parameter space in which weakly ionized cosmic gases may be characterized as plasmas. In this short note, we do so. First, we use values for the ionization fraction given in the literature, wherein the ionization is generally assumed to be due primarily to ionization by cosmic rays. We also discuss an additional mechanism for ionization in such environments, namely, the photoelectric emission of electrons from cosmic dust grains in an interstellar Far Ultra Violet (FUV) radiation field. Simple estimates suggest that under certain conditions this mechanism may dominate cosmic ray ionization, and possibly also the photoionization of metal atoms by the interstellar FUV field, and thereby lead to an enhanced ionization level.

  16. Phospholipid Topography of Whole-Body Sections of the Anopheles stephensi Mosquito, Characterized by High-Resolution Atmospheric-Pressure Scanning Microprobe Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging.

    PubMed

    Khalil, Saleh M; Römpp, Andreas; Pretzel, Jette; Becker, Katja; Spengler, Bernhard

    2015-11-17

    High-resolution atmospheric-pressure scanning microprobe matrix-assisted laser desorption/ionization mass spectrometry imaging (AP-SMALDI MSI) has been employed to study the molecular anatomical structure of rodent malaria vector Anopheles stephensi mosquitoes. A dedicated sample preparation method was developed which suits both, the special tissue properties of the sample and the requirements of high-resolution MALDI imaging. Embedding in 5% carboxymethylcellulose (CMC) was used to maintain the tissue integrity of the whole mosquitoes, being very soft, fragile, and difficult to handle. Individual lipid compounds, specifically representing certain cell types, tissue areas, or organs, were detected and imaged in 20 μm-thick whole-body tissue sections at a spatial resolution of 12 μm per image pixel. Mass spectrometric data and information quality were based on a mass resolution of 70,000 (at m/z 200) and a mass accuracy of better than 2 ppm in positive-ion mode on an orbital trapping mass spectrometer. A total of 67 imaged lipids were assigned by database search and, in a number of cases, identified via additional MS/MS fragmentation studies directly from tissue. This is the first MSI study at 12 μm spatial resolution of the malaria vector Anopheles. The study provides insights into the molecular anatomy of Anopheles stephensi and the distribution and localization of major classes of glycerophospholipids and sphingolipids. These data can be a basis for future experiments, investigating, e.g., the metabolism of Plasmodium-infected and -uninfected Anopheles mosquitoes. PMID:26491885

  17. Communication: Electron ionization of DNA bases.

    PubMed

    Rahman, M A; Krishnakumar, E

    2016-04-28

    No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space. PMID:27131520

  18. Communication: Electron ionization of DNA bases

    NASA Astrophysics Data System (ADS)

    Rahman, M. A.; Krishnakumar, E.

    2016-04-01

    No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space.

  19. Dissociative-ionization cross sections for 12-keV-electron impact on CO{sub 2}

    SciTech Connect

    Bhatt, Pragya; Singh, Raj; Yadav, Namita; Shanker, R.

    2011-10-15

    The dissociative ionization of a CO{sub 2} molecule is studied at an electron energy of 12 keV using the multiple ion coincidence imaging technique. The absolute partial ionization cross sections and the precursor-specific absolute partial ionization cross sections of resulting fragment ions are obtained and reported. It is found that {approx}75% of single ionization, 22% of double ionization, and {approx}2% of triple ionization of the parent molecule contribute to the total fragment ion yield; quadruple ionization of CO{sub 2} is found to make a negligibly small contribution. Furthermore, the absolute partial ionization cross sections for ion-pair and ion-triple formation are measured for nine dissociative ionization channels of up to a quadruply ionized CO{sub 2} molecule. In addition, the branching ratios for single-ion, ion-pair, and ion-triple formation are also determined.

  20. Ionization potentials of seaborgium

    SciTech Connect

    Johnson, E.; Pershina, V.; Fricke, B.

    1999-10-21

    Multiconfiguration relativistic Dirac-Fock values were calculated for the first six ionization potentials of seaborgium and of the other group 6 elements. No experimental ionization potentials are available for seaborgium. Accurate experimental values are not available for all of the other ionization potentials. Ionic radii for the 4+ through 6+ ions of seaborgium are also presented. The ionization potentials and ionic radii obtained will be used to predict some physiochemical properties of seaborgium and its compounds.

  1. Ionization Energies of Lanthanides

    ERIC Educational Resources Information Center

    Lang, Peter F.; Smith, Barry C.

    2010-01-01

    This article describes how data are used to analyze the pattern of ionization energies of the lanthanide elements. Different observed pathways of ionization between different ground states are discussed, and the effects of pairing, exchange, and orbital interactions on ionization energies of the lanthanides are evaluated. When all the above…

  2. Nanotip Ambient Ionization Mass Spectrometry.

    PubMed

    Zhou, Zhenpeng; Lee, Jae Kyoo; Kim, Samuel C; Zare, Richard N

    2016-05-17

    A method called nanotip ambient ionization mass spectrometry (NAIMS) is described, which applies high voltage between a tungsten nanotip and a metal plate to generate a plasma in which ionized analytes on the surface of the metal plate are directed to the inlet and analyzed by a mass spectrometer. The dependence of signal intensity is investigated as a function of the tip-to-plate distance, the tip size, the voltage applied at the tip, and the current. These parameters are separately optimized to achieve sensitivity or high spatial resolution. A partially observable Markov decision process is used to achieve a stabilized plasma as well as high ionization efficiency. As a proof of concept, the NAIMS technique has been applied to phenanthrene and caffeine samples for which the limits of detection were determined to be 0.14 fmol for phenanthrene and 4 amol for caffeine and to a printed caffeine pattern for which a spatial resolution of 8 ± 2 μm, and the best resolution of 5 μm, was demonstrated. The limitations of NAIMS are also discussed. PMID:27087600

  3. Ambient Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Huang, Min-Zong; Yuan, Cheng-Hui; Cheng, Sy-Chyi; Cho, Yi-Tzu; Shiea, Jentaie

    2010-07-01

    Mass spectrometric ionization methods that operate under ambient conditions and require minimal or no sample pretreatment have attracted much attention in such fields as biomedicine, food safety, antiterrorism, pharmaceuticals, and environmental pollution. These technologies usually involve separate ionization and sample-introduction events, allowing independent control over each set of conditions. Ionization is typically performed under ambient conditions through use of existing electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) techniques. Rapid analyses of gas, liquid, and solid samples are possible with the adoption of various sample-introduction methods. This review sorts different ambient ionization techniques into two main subcategories, primarily on the basis of the ionization processes, that are further differentiated in terms of the approach used for sampling.

  4. Above-threshold ionization of negative hydrogen

    NASA Astrophysics Data System (ADS)

    Nikolopoulos, L. A. A.; Lambropoulos, P.

    1997-10-01

    We present detailed calculations for two-and three-photon above-threshold ionization of the negative hydrogen ion. In addition to calculated values for partial wave amplitudes and phase shifts pertaining to recent experimental results [Xin Miao Zhao et al., Phys. Rev. Lett. 78, 1656 (1997)], we also address the question of the asymmetry of photoelectron angular distributions in ionization under elliptically polarized radiation, which has been studied experimentally in other negative ions [C. Blondel and C. Delsart, Laser Phys. 3, 3 (1993); Nucl. Instrum. Methods Phys. Res. B 79, 156 (1993); F. Dulieu, C. Blondel, and C. Delsart, J. Phys. B 28, 3861 (1995)].

  5. Radiation injury and acute death in Armadillidium vulgare (terrestrial isopod, Crustacea) subjected to ionizing radiation. [/sup 137/Cs

    SciTech Connect

    Nakatsuchi, Y.; Egami, N.

    1981-01-01

    From whole- and partial-body irradiation experiments with adult Armadillidium vulgare, the following conclusions were drawn: the LD/sub 50/-30 days for this animal when subjected to ..gamma.. radiation at 25 +- 2/sup 0/C was about 30 kR. Radiosensitivity of the animal changed during the molt cycle. Ionizing radiation increased mortality at ecdysis and during intermolt stages. Anatomical and histological observations indicated that (1) gastrointestinal injury as the major cause of acute death does not apply to this animal because the intestine is not a cell-proliferative organ: (2) the epidermis may be the critical target organ.

  6. Partial Return Yoke for MICE Step IV and Final Step

    SciTech Connect

    Witte, Holger; Plate, Stephen; Berg, J.Scott; Tarrant, Jason; Bross, Alan

    2015-06-01

    This paper reports on the progress of the design and construction of a retro-fitted return yoke for the international Muon Ionization Cooling Experiment (MICE). MICE is a proof-of-principle experiment aiming to demonstrate ionization cooling experimentally. In earlier studies we outlined how a partial return yoke can be used to mitigate stray magnetic field in the experimental hall; we report on the progress of the construction of the partial return yoke for MICE Step IV. We also discuss an extension of the Partial Return Yoke for the final step of MICE; we show simulation results of the expected performance.

  7. Partial return yoke for MICE step IV and final step

    SciTech Connect

    Witte, H.; Plate, S.; Berg, J. S.; Tarrant, J.; Bross, A.

    2015-05-03

    This paper reports on the progress of the design and construction of a retro-fitted return yoke for the international Muon Ionization Cooling Experiment (MICE). MICE is a proof-of-principle experiment aiming to demonstrate ionization cooling experimentally. In earlier studies we outlined how a partial return yoke can be used to mitigate stray magnetic field in the experimental hall; we report on the progress of the construction of the partial return yoke for MICE Step IV. We also discuss an extension of the Partial Return Yoke for the final step of MICE; we show simulation results of the expected performance.

  8. Silurian/Ordovician asymmetrical sill-like bodies from La Codosera syncline, W Spain: A case of tholeiitic partial melts emplaced in a single magma pulse and derived from a metasomatized mantle source

    NASA Astrophysics Data System (ADS)

    López-Moro, F. J.; Murciego, A.; López-Plaza, M.

    2007-07-01

    A Silurian/Ordovician extensional event in the southernmost sectors of the Central Iberian Zone is inferred from the Sm/Nd isochron obtained (436 ± 17 Ma) after the diabase sills from the La Codosera syncline. From the geochemical and mineralogical points of view, the diabase sills are subalkaline and range between high-Mg tholeiite diabases to tholeiite andesites. LREE enrichment, an Nb negative anomaly, the absence of a Ta trough and a high Nd isotope signature ( ɛNd t = + 6) are the most relevant geochemical features. The diabase bodies are up to 330 m in thickness and were sampled from bottom to top along several different sections, permitting the definition of an accumulation of clinopyroxene, olivine and plagioclase close to chilled margins at the bottom, and abundant pegmatoid layers at the top. Chemical profiles and mass-balance modelling suggest that the bulk rock and chilled margin compositions are not dissimilar, defining an unusual S-type vertical compositional profile for large (> 50 m thick) sills, which in turn strongly suggests a single magma pulse and a probable gravitational settling. Assuming chilled margin samples as the parental magma, as well as Cr-enriched samples as cumulate layers, a two-stage liquid line of descent has been established, the first one consisting of a clinopyroxene-plagioclase-olivine cumulate assemblage. A second stage in relation to the depletion in Ti, Fe and V is accounted for by ilmenite fractionation, along with that of clinopyroxene, plagioclase and olivine fractionation. Thermobarometric estimations reveal that the clinopyroxene (around 1100 °C and 197 MPa) was a late mineral phase, whereas the plagioclase (around 1200 °C) was pre- to syn-emplacement, in agreement with the presence only of plagioclase phenocrysts in the chilled margins and the very abundant positive Eu anomaly. The energy constraint modelling is consistent with the lack of a significant assimilation process owing to the high temperature contrast

  9. Reinforced polyquinoxaline gasket and method of preparing the same. [resistant to ionizing radiation and liquid hydrogen temperatures

    NASA Technical Reports Server (NTRS)

    Vanauken, R. (Inventor)

    1974-01-01

    A gasket or seal resistant to ionizing radiation and liquid hydrogen temperatures is made up of a laminated polyquinoxaline resin-fiberglass cloth body portion and a molded polyquinoxaline encapsulating film. The laminated body is prepared by stacking thin sheets of the resin alternately with fiberglass cloth and heating the assembly under pressure with the temperature, pressure and resin film thickness being controlled so that only partial impregnation of the fiberglass cloth is produced. The encapsulating resin film is preheated at about 300 f and applied to the laminate body by molding at a temperature of about 625 F. The molded gasket is then deflashed and post-cured by heating at 675 to 700 F.

  10. Hydraulic effects in a radiative atmosphere with ionization

    NASA Astrophysics Data System (ADS)

    Bhat, P.; Brandenburg, A.

    2016-03-01

    Context. In his 1978 paper, Eugene Parker postulated the need for hydraulic downward motion to explain magnetic flux concentrations at the solar surface. A similar process has also recently been seen in simplified (e.g., isothermal) models of flux concentrations from the negative effective magnetic pressure instability (NEMPI). Aims: We study the effects of partial ionization near the radiative surface on the formation of these magnetic flux concentrations. Methods: We first obtain one-dimensional (1D) equilibrium solutions using either a Kramers-like opacity or the H- opacity. The resulting atmospheres are then used as initial conditions in two-dimensional (2D) models where flows are driven by an imposed gradient force that resembles a localized negative pressure in the form of a blob. To isolate the effects of partial ionization and radiation, we ignore turbulence and convection. Results: Because of partial ionization, an unstable stratification always forms near the surface. We show that the extrema in the specific entropy profiles correspond to the extrema in the degree of ionization. In the 2D models without partial ionization, strong flux concentrations form just above the height where the blob is placed. Interestingly, in models with partial ionization, such flux concentrations always form at the surface well above the blob. This is due to the corresponding negative gradient in specific entropy. Owing to the absence of turbulence, the downflows reach transonic speeds. Conclusions: We demonstrate that, together with density stratification, the imposed source of negative pressure drives the formation of flux concentrations. We find that the inclusion of partial ionization affects the entropy profile dramatically, causing strong flux concentrations to form closer to the surface. We speculate that turbulence effects are needed to limit the strength of flux concentrations and homogenize the specific entropy to a stratification that is close to marginal.

  11. Ionization of water by (20-150)-keV protons: Separation of direct-ionization and electron-capture processes

    SciTech Connect

    Gobet, F.; Eden, S.; Coupier, B.; Tabet, J.; Farizon, B.; Farizon, M.; Gaillard, M.J.; Carre, M.; Ouaskit, S.; Maerk, T. D.; Scheier, P.

    2004-12-01

    Mass analyzed product ions have been detected in coincidence with the projectile following the ionization of water by proton impact. Measurement of the projectile charge state postcollision enables the different ionization processes to be identified: direct ionization, single electron capture, and double electron capture. A complete set of partial and total absolute cross sections is reported for the direct ionization and electron capture processes initiated by proton collisions at 20-150 keV. The cross sections for the direct ionization of H{sub 2}O by proton impact are compared with previous electron impact results [Straub et al., J. Chem. Phys. 108, 109 (1998)].

  12. Biological Effects of Ionizing Radiation

    DOE R&D Accomplishments Database

    Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

    1952-04-07

    This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

  13. Ionization of water molecules by fast charged projectiles

    SciTech Connect

    Dubois, A.; Carniato, S.; Fainstein, P. D.; Hansen, J. P.

    2011-07-15

    Single-ionization cross sections of water molecules colliding with fast protons are calculated from lowest-order perturbation theory by taking all electrons and molecular orientations consistently into account. Explicit analytical formulas based on the peaking approximation are obtained for differential ionization cross sections with the partial contribution from the various electron orbitals accounted for. The results, which are in very good agreement with total and partial cross sections at high electron and projectile energies, display a strong variation on molecular orientation and molecular orbitals.

  14. Partial (focal) seizure

    MedlinePlus

    ... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff RB, ... 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 67. ...

  15. Partial (focal) seizure

    MedlinePlus

    ... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff ... Practice . 7th ed. Philadelphia, PA: Elsevier; 2016:chap 101. ...

  16. Partial tooth gear bearings

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  17. "Magic" Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The "magic" that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers.

  18. "Magic" Ionization Mass Spectrometry.

    PubMed

    Trimpin, Sarah

    2016-01-01

    The systematic study of the temperature and pressure dependence of matrix-assisted ionization (MAI) led us to the discovery of the seemingly impossible, initially explained by some reviewers as either sleight of hand or the misinterpretation by an overzealous young scientist of results reported many years before and having little utility. The “magic” that we were attempting to report was that with matrix assistance, molecules, at least as large as bovine serum albumin (66 kDa), are lifted into the gas phase as multiply charged ions simply by exposure of the matrix:analyte sample to the vacuum of a mass spectrometer. Applied heat, a laser, or voltages are not necessary to achieve charge states and ion abundances only previously observed with electrospray ionization (ESI). The fundamentals of how solid phase volatile or nonvolatile compounds are converted to gas-phase ions without added energy currently involves speculation providing a great opportunity to rethink mechanistic understanding of ionization processes used in mass spectrometry. Improved understanding of the mechanism(s) of these processes and their connection to ESI and matrix-assisted laser desorption/ionization may provide opportunities to further develop new ionization strategies for traditional and yet unforeseen applications of mass spectrometry. This Critical Insights article covers developments leading to the discovery of a seemingly magic ionization process that is simple to use, fast, sensitive, robust, and can be directly applied to surface characterization using portable or high performance mass spectrometers. PMID:26486514

  19. Alkali metal ionization detector

    DOEpatents

    Bauerle, James E.; Reed, William H.; Berkey, Edgar

    1978-01-01

    Variations in the conventional filament and collector electrodes of an alkali metal ionization detector, including the substitution of helical electrode configurations for either the conventional wire filament or flat plate collector; or, the substitution of a plurality of discrete filament electrodes providing an in situ capability for transferring from an operationally defective filament electrode to a previously unused filament electrode without removing the alkali metal ionization detector from the monitored environment. In particular, the helical collector arrangement which is coaxially disposed about the filament electrode, i.e. the thermal ionizer, provides an improved collection of positive ions developed by the filament electrode. The helical filament design, on the other hand, provides the advantage of an increased surface area for ionization of alkali metal-bearing species in a monitored gas environment as well as providing a relatively strong electric field for collecting the ions at the collector electrode about which the helical filament electrode is coaxially positioned. Alternatively, both the filament and collector electrodes can be helical. Furthermore, the operation of the conventional alkali metal ionization detector as a leak detector can be simplified as to cost and complexity, by operating the detector at a reduced collector potential while maintaining the sensitivity of the alkali metal ionization detector adequate for the relatively low concentration of alkali vapor and aerosol typically encountered in leak detection applications.

  20. Electron impact ionization of glycolaldehyde

    NASA Astrophysics Data System (ADS)

    Ptasinska, Sylwia; Denifl, Stephan; Scheier, Paul; Märk, Tilmann D.

    2005-05-01

    Positive ion formation upon electron impact ionization of the monomeric and dimeric form of glycolaldehyde is studied with high electron energy resolution. In the effusive neutral beam of evaporated monomeric glycolaldehyde some ions with a mass larger than the monomer indicate the presence of weakly bound neutral dimers. The yield of all ions that originate from the electron impact ionization of these neutral dimers exhibit a strong temperature dependence that can be interpreted as being due to the formation of dimers via three body collisions and thermal decomposition of the dimeric form back into monomers at higher temperatures. Ion efficiency curves are measured and analyzed for the 10 most abundant product cations of monomeric glycolaldehyde. The appearance energies of the parent ion signals of the monomer and dimer of glycolaldehyde (10.2 and 9.51 eV, respectively) are lower than the appearance energy of the parent cation of the more complex sugar deoxyribose that was recently determined to be 10.51 eV.

  1. Partially molten magma ocean model

    SciTech Connect

    Shirley, D.N.

    1983-02-15

    The properties of the lunar crust and upper mantle can be explained if the outer 300-400 km of the moon was initially only partially molten rather than fully molten. The top of the partially molten region contained about 20% melt and decreased to 0% at 300-400 km depth. Nuclei of anorthositic crust formed over localized bodies of magma segregated from the partial melt, then grew peripherally until they coverd the moon. Throughout most of its growth period the anorthosite crust floated on a layer of magma a few km thick. The thickness of this layer is regulated by the opposing forces of loss of material by fractional crystallization and addition of magma from the partial melt below. Concentrations of Sr, Eu, and Sm in pristine ferroan anorthosites are found to be consistent with this model, as are trends for the ferroan anorthosites and Mg-rich suites on a diagram of An in plagioclase vs. mg in mafics. Clustering of Eu, Sr, and mg values found among pristine ferroan anorthosites are predicted by this model.

  2. Alfvén ionization in an MHD-gas interactions code

    NASA Astrophysics Data System (ADS)

    Wilson, A. D.; Diver, D. A.

    2016-07-01

    A numerical model of partially ionized plasmas is developed in order to capture their evolving ionization fractions as a result of Alfvén ionization (AI). The mechanism of, and the parameter regime necessary for, AI is discussed and an expression for the AI rate based on fluid parameters, from a gas-MHD model, is derived. This AI term is added to an existing MHD-gas interactions' code, and the result is a linear, 2D, two-fluid model that includes momentum transfer between charged and neutral species as well as an ionization rate that depends on the velocity fields of both fluids. The dynamics of waves propagating through such a partially ionized plasma are investigated, and it is found that AI has a significant influence on the fluid dynamics as well as both the local and global ionization fraction.

  3. Fuel cell with ionization membrane

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T. (Inventor)

    2007-01-01

    A fuel cell is disclosed comprising an ionization membrane having at least one area through which gas is passed, and which ionizes the gas passing therethrough, and a cathode for receiving the ions generated by the ionization membrane. The ionization membrane may include one or more openings in the membrane with electrodes that are located closer than a mean free path of molecules within the gas to be ionized. Methods of manufacture are also provided.

  4. Body Hair

    MedlinePlus

    ... girlshealth.gov/ Home Body Puberty Body hair Body hair Even before you get your first period , you ... removing pubic hair Ways to get rid of hair top Removing body hair can cause skin irritation, ...

  5. Dissociative Ionization of Benzene by Electron Impact

    NASA Technical Reports Server (NTRS)

    Huo, Winifred; Dateo, Christopher; Kwak, Dochan (Technical Monitor)

    2002-01-01

    We report a theoretical study of the dissociative ionization (DI) of benzene from the low-lying ionization channels. Our approach makes use of the fact that electron motion is much faster than nuclear motion and DI is treated as a two-step process. The first step is electron-impact ionization resulting in an ion with the same nuclear geometry as the neutral molecule. In the second step the nuclei relax from the initial geometry and undergo unimolecular dissociation. For the ionization process we use the improved binary-encounter dipole (iBED) model. For the unimolecular dissociation step, we study the steepest descent reaction path to the minimum of the ion potential energy surface. The path is used to analyze the probability of unimolecular dissociation and to determine the product distributions. Our analysis of the dissociation products and the thresholds of the productions are compared with the result dissociative photoionization measurements of Feng et al. The partial oscillator strengths from Feng et al. are then used in the iBED cross section calculations.

  6. Surface ionization of terpene hydrocarbons

    SciTech Connect

    Zandberg, E.Y.; Nezdyurov, A.L.; Paleev, V.I.; Ponomarev, D.A.

    1986-09-01

    By means of a surface ionization indicator for traces of materials in the atmosphere it has been established that many natural materials containing terpenes and their derivatives are ionized on the surface of heated molybdenum oxide at atmospheric air pressure. A mass-spectrometer method has been used to explain the mechanism of ionization of individual terpene hydrocarbons and to establish its principles. The ionization of ..cap alpha..-pinene, alloocimene, camphene, and also adamantane on oxidized tungsten under vacuum conditions has been investigated. The ..cap alpha..-pinene and alloocimene are ionized by surface ionization but camphene and adamantane are not ionized under vacuum conditions. The surface ionization mass spectra of ..cap alpha..-pinene and alloocimene are of low line brightness in comparison with electron ionization mass spectra and differ between themselves. The temperature relations for currents of the same compositions of ions during ionization of ..cap alpha..-pinene and alloocimene are also different, which leads to the possibility of surface ionization analysis of mixtures of terpenes being ionized. The ionization coefficients of alloocimene and ..cap alpha..-pinene on oxidized tungsten under temperatures optimum for ionization and the ionization potentials of alloocimene molecules and of radicals (M-H) of both compounds have been evaluated.

  7. Atmospheric Ionization Measurements

    NASA Astrophysics Data System (ADS)

    Slack, Thomas; Mayes, Riley

    2015-04-01

    The measurement of atmospheric ionization is a largely unexplored science that potentially holds the key to better understanding many different geophysical phenomena through this new and valuable source of data. Through the LaACES program, which is funded by NASA through the Louisiana Space Consortium, students at Loyola University New Orleans have pursued the goal of measuring high altitude ionization for nearly three years, and were the first to successfully collect ionization data at altitudes over 30,000 feet using a scientific weather balloon flown from the NASA Columbia Scientific Ballooning Facility in Palestine, TX. In order to measure atmospheric ionization, the science team uses a lightweight and highly customized sensor known as a Gerdien condenser. Among other branches of science the data is already being used for, such as the study of aerosol pollution levels in the atmosphere, the data may also be useful in meteorology and seismology. Ionization data might provide another variable with which to predict weather or seismic activity more accurately and further in advance. Thomas Slack and Riley Mayes have served as project managers for the experiment, and have extensive knowledge of the experiment from the ground up. LaSPACE Louisiana Space Consortium.

  8. Electron Impact Ionization Cross Sections and Rate Coefficients for Single Carbon Freon Molecules

    NASA Astrophysics Data System (ADS)

    Pal, Satyendra; Kumar, Neeraj

    2015-09-01

    Single carbon Freon molecules or chlorofluorocarbons (CFCs) are important industrial material with wide-ranging applications as refrigerant, aerosol propellant and semiconductor etchant, etc. The large-scale industrial consumption is of particular environmental concern because of its potential for ozone destruction in the stratosphere. In the present work, we have extended and generalized the modified Jain-Khare (JK) semi-empirical formalism for the evaluation of the total ionization cross sections corresponding to the formation of the cations in the electron impact ionization of molecules to the electron impact ionization of single carbon freon molecules, viz. CFCl3, CF2Cl2 and CF3Cl. The integral partial and the total ionization cross sections as function of incident electron energy are evaluated in the energy range varying from ionization threshold to 1000 eV. In absence of available differential cross sections, the corresponding derived partial and total ionization cross sections revealed a reasonably good agreement with the experimental and theoretical data, wherever available. In addition to the differential and integral ionization cross sections, we have also calculated the ionization rate coefficients using the evaluated partial ionization cross sections and the Maxwell-Boltzmann distribution as a function of electron temperature/energy. The work is supported by DST, New Delhi, India.

  9. The Electrical Conductivity Of Partly Ionized Helium Plasma

    SciTech Connect

    Sreckovic, Vladimir A.; Ignjatovic, Ljubinko; Mihajlov, A. A.

    2007-04-23

    In this paper we analyzed atoms influence on electro conductivity, partially ionized helium plasma, in temperature region 5 000 K - 40 000 K and pressure 0.1 - 10 atm. Electro conductivity was calculated using 'Frost like' formula and Random Phase Approximation method and Semi-Classical (SC) approximation.

  10. A numerical scheme for ionizing shock waves

    SciTech Connect

    Aslan, Necdet . E-mail: naslan@yeditepe.edu.tr; Mond, Michael

    2005-12-10

    A two-dimensional (2D) visual computer code to solve the steady state (SS) or transient shock problems including partially ionizing plasma is presented. Since the flows considered are hypersonic and the resulting temperatures are high, the plasma is partially ionized. Hence the plasma constituents are electrons, ions and neutral atoms. It is assumed that all the above species are in thermal equilibrium, namely, that they all have the same temperature. The ionization degree is calculated from Saha equation as a function of electron density and pressure by means of a nonlinear Newton type root finding algorithms. The code utilizes a wave model and numerical fluctuation distribution (FD) scheme that runs on structured or unstructured triangular meshes. This scheme is based on evaluating the mesh averaged fluctuations arising from a number of waves and distributing them to the nodes of these meshes in an upwind manner. The physical properties (directions, strengths, etc.) of these wave patterns are obtained by a new wave model: ION-A developed from the eigen-system of the flux Jacobian matrices. Since the equation of state (EOS) which is used to close up the conservation laws includes electronic effects, it is a nonlinear function and it must be inverted by iterations to determine the ionization degree as a function of density and temperature. For the time advancement, the scheme utilizes a multi-stage Runge-Kutta (RK) algorithm with time steps carefully evaluated from the maximum possible propagation speed in the solution domain. The code runs interactively with the user and allows to create different meshes to use different initial and boundary conditions and to see changes of desired physical quantities in the form of color and vector graphics. The details of the visual properties of the code has been published before (see [N. Aslan, A visual fluctuation splitting scheme for magneto-hydrodynamics with a new sonic fix and Euler limit, J. Comput. Phys. 197 (2004) 1

  11. Alkali ionization detector

    DOEpatents

    Hrizo, John; Bauerle, James E.; Witkowski, Robert E.

    1982-01-01

    A calibration filament containing a sodium-bearing compound is included in combination with the sensing filament and ion collector plate of a sodium ionization detector to permit periodic generation of sodium atoms for the in-situ calibration of the detector.

  12. Positive ionization of hyperthermal sodium atoms on metal surfaces

    NASA Astrophysics Data System (ADS)

    Overbosch, E. G.; Los, J.

    1981-06-01

    The efficiency for positive ionization of Na atoms, reflected from a metallic surface at room temperature, has been measured in the incident energy range Ein = 25-400 eV at an angle of incidence θi = 60°. The surface is W(110) partially covered with sodium atoms. The ionization is almost complete on clean tungsten for all incident energies, and decreases to zero as a function of coverage. Fifty per cent of a 100 eV primary beam is ionized at a surface coverage of 0.8 × 10 14{atoms}/{cm2} (˜0.1 monolayer). Faster projectiles demand larger coverages to be ionized for fifty per cent. The steepness of the ionization curves as a function of coverage decreases as a function of energy. In general it is found, that the ionization probability of backscattered atoms is larger at increasing incident energy. Comparison of the measured data with the theory of resonance ionization/neutralization confirms the model, and shows that the calculated shift of the valence level of the Na atom near the surface is in agreement with the experimental results.

  13. Integrated atom detector based on field ionization near carbon nanotubes

    SciTech Connect

    Gruener, B.; Jag, M.; Stibor, A.; Visanescu, G.; Haeffner, M.; Kern, D.; Guenther, A.; Fortagh, J.

    2009-12-15

    We demonstrate an atom detector based on field ionization and subsequent ion counting. We make use of field enhancement near tips of carbon nanotubes to reach extreme electrostatic field values of up to 9x10{sup 9} V/m, which ionize ground-state rubidium atoms. The detector is based on a carpet of multiwall carbon nanotubes grown on a substrate and used for field ionization, and a channel electron multiplier used for ion counting. We measure the field enhancement at the tips of carbon nanotubes by field emission of electrons. We demonstrate the operation of the field ionization detector by counting atoms from a thermal beam of a rubidium dispenser source. By measuring the ionization rate of rubidium as a function of the applied detector voltage we identify the field ionization distance, which is below a few tens of nanometers in front of nanotube tips. We deduce from the experimental data that field ionization of rubidium near nanotube tips takes place on a time scale faster than 10{sup -10} s. This property is particularly interesting for the development of fast atom detectors suitable for measuring correlations in ultracold quantum gases. We also describe an application of the detector as partial pressure gauge.

  14. Ionization Driven Chemistry in Protoplanetary Disks and Observational Signatures of Ionization Suppression

    NASA Astrophysics Data System (ADS)

    Cleeves, Lauren Ilsedore; Bergin, Edwin A.

    2015-01-01

    Circumstellar disks around young stars set the stage for the formation of planetary systems. The ionization fraction of the disk fundamentally regulates turbulence, which drives accretion onto the star and plays a role in the formation of planetesimals. Ionization is also central to the chemistry of the coldest disk gas, where comets and other icy bodies are assembled. During my PhD I studied the expected levels --- including possible severe suppression --- of the primary ionizing agents in disks, including cosmic rays, X-rays and the decay of short-lived radionuclides. Within this framework, I examined how each of these sources impacts turbulence-free "dead zones," and I identified submillimeter molecular emission tracers that can be used to spatially map-out ionization in disks with ALMA. I applied these theoretical results to SMA and ALMA observations of the extensively studied TW Hya protoplanetary disk, and I measured a disk-averaged upper limit to the cosmic ray ionization rate ~100 times below the canonical rate of 10-17 s-1 per H2. These results point to extensive CR deflection by either natal winds or twisted magnetic fields from the background environment or within the disk itself. One of the important implications of this work is that cold disk chemistry is inefficient without sufficient ionization, and as a direct result, deuterated water (HDO) is not significantly produced in disks. Given the elevated levels of HDO/H2O present throughout Solar System bodies, these results point to a substantial interstellar inheritance of deuterium-enriched ices during the formation of our own planetary system.

  15. Modulated voltage metastable ionization detector

    NASA Technical Reports Server (NTRS)

    Carle, G. C.; Kojiro, D. R.; Humphrey, D. E. (Inventor)

    1985-01-01

    The output current from a metastable ionization detector (MID) is applied to a modulation voltage circuit. An adjustment is made to balance out the background current, and an output current, above background, is applied to an input of a strip chart recorder. For low level concentrations, i.e., low detected output current, the ionization potential will be at a maximum and the metastable ionization detector will operate at its most sensitive level. When the detected current from the metastable ionization detector increases above a predetermined threshold level, a voltage control circuit is activated which turns on a high voltage transistor which acts to reduce the ionization potential. The ionization potential applied to the metastable ionization detector is then varied so as to maintain the detected signal level constant. The variation in ionization potential is now related to the concentration of the constituent and a representative amplitude is applied to another input of said strip chart recorder.

  16. Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    DOE PAGESBeta

    Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J.; Gan, Jinping; Kertesz, Vilmos

    2015-11-03

    Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites was studied. Major organs (brain, lung, liver, kidney, muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed themore » same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. Furthermore, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement.« less

  17. Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

    SciTech Connect

    Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J.; Gan, Jinping; Kertesz, Vilmos

    2015-11-03

    Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites was studied. Major organs (brain, lung, liver, kidney, muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed the same patterns for post-dose time points (0.25, 0.5, 1 and 2 h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. Furthermore, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement.

  18. Quantitation of repaglinide and metabolites in mouse whole-body thin tissue sections using droplet-based liquid microjunction surface sampling-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry.

    PubMed

    Chen, Weiqi; Wang, Lifei; Van Berkel, Gary J; Kertesz, Vilmos; Gan, Jinping

    2016-03-25

    Herein, quantitation aspects of a fully automated autosampler/HPLC-MS/MS system applied for unattended droplet-based surface sampling of repaglinide dosed thin tissue sections with subsequent HPLC separation and mass spectrometric analysis of parent drug and various drug metabolites were studied. Major organs (brain, lung, liver, kidney and muscle) from whole-body thin tissue sections and corresponding organ homogenates prepared from repaglinide dosed mice were sampled by surface sampling and by bulk extraction, respectively, and analyzed by HPLC-MS/MS. A semi-quantitative agreement between data obtained by surface sampling and that by employing organ homogenate extraction was observed. Drug concentrations obtained by the two methods followed the same patterns for post-dose time points (0.25, 0.5, 1 and 2h). Drug amounts determined in the specific tissues was typically higher when analyzing extracts from the organ homogenates. In addition, relative comparison of the levels of individual metabolites between the two analytical methods also revealed good semi-quantitative agreement. PMID:26589943

  19. Ultrahigh vacuum measuring ionization gauge

    NASA Technical Reports Server (NTRS)

    Brock, F. J. (Inventor)

    1968-01-01

    The ionization gage described consists of separate ionization and collector regions connected at an exit area with a modulator electrode. In addition to the standard modulation function, the modulator in this location yields a suprising increase in collector current, apparently due to improved focussing and extraction of ions from the ionization region.

  20. First-Principles Investigation to Ionization of Argon Under Conditions Close to Typical Sonoluminescence Experiments

    PubMed Central

    Kang, Wei; Zhao, Shijun; Zhang, Shen; Zhang, Ping; Chen, Q. F.; He, Xian-Tu

    2016-01-01

    Mott effect, featured by a sharp increase of ionization, is one of the unique properties of partially ionized plasmas, and thus of great interest to astrophysics and inertial confinement fusion. Recent experiments of single bubble sonoluminescence (SBSL) revealed that strong ionization took place at a density two orders lower than usual theoretical expectation. We show from the perspective of electronic structures that the strong ionization is unlikely the result of Mott effect in a pure argon plasma. Instead, first-principles calculations suggest that other ion species from aqueous environments can energetically fit in the gap between the continuum and the top of occupied states of argon, making the Mott effect possible. These results would help to clarify the relationship between SBSL and Mott effect, and further to gain an better understanding of partially ionized plasmas. PMID:26853107

  1. First-Principles Investigation to Ionization of Argon Under Conditions Close to Typical Sonoluminescence Experiments

    NASA Astrophysics Data System (ADS)

    Kang, Wei; Zhao, Shijun; Zhang, Shen; Zhang, Ping; Chen, Q. F.; He, Xian-Tu

    2016-02-01

    Mott effect, featured by a sharp increase of ionization, is one of the unique properties of partially ionized plasmas, and thus of great interest to astrophysics and inertial confinement fusion. Recent experiments of single bubble sonoluminescence (SBSL) revealed that strong ionization took place at a density two orders lower than usual theoretical expectation. We show from the perspective of electronic structures that the strong ionization is unlikely the result of Mott effect in a pure argon plasma. Instead, first-principles calculations suggest that other ion species from aqueous environments can energetically fit in the gap between the continuum and the top of occupied states of argon, making the Mott effect possible. These results would help to clarify the relationship between SBSL and Mott effect, and further to gain an better understanding of partially ionized plasmas.

  2. First-Principles Investigation to Ionization of Argon Under Conditions Close to Typical Sonoluminescence Experiments.

    PubMed

    Kang, Wei; Zhao, Shijun; Zhang, Shen; Zhang, Ping; Chen, Q F; He, Xian-Tu

    2016-01-01

    Mott effect, featured by a sharp increase of ionization, is one of the unique properties of partially ionized plasmas, and thus of great interest to astrophysics and inertial confinement fusion. Recent experiments of single bubble sonoluminescence (SBSL) revealed that strong ionization took place at a density two orders lower than usual theoretical expectation. We show from the perspective of electronic structures that the strong ionization is unlikely the result of Mott effect in a pure argon plasma. Instead, first-principles calculations suggest that other ion species from aqueous environments can energetically fit in the gap between the continuum and the top of occupied states of argon, making the Mott effect possible. These results would help to clarify the relationship between SBSL and Mott effect, and further to gain an better understanding of partially ionized plasmas. PMID:26853107

  3. Inviscid Partial Coalescence from Bubbles to Drops

    NASA Astrophysics Data System (ADS)

    Zhang, F. H.; Taborek, P.; Burton, J.; Khoo, B. C.; Lim, K. M.; Thoroddsen, S. T.

    2010-11-01

    Coalescence of bubbles (drops) not only coarse the bubble (drop) sizes, but sometimes produces satellite bubbles (droplets), known as partial coalescence. To explore links between the drop and bubble cases, we experimentally study the partial coalescence of pressurized xenon gas bubbles in nano de-ionized water using high-speed video imaging. The size of these satellites relative to their mother bubbles is found to increase with the density ratio of the gas to the liquid. Moreover, sub-satellite bubbles are sometimes observed, whose size is also found to increase with the density ratio, while keeps about one quarter of the primary satellite. The time duration from start of the coalescence to formation of the satellites, scaled by the capillary time, increases with the density ratio too. In addition, as the size ratio of the father bubble to the mother bubble increases moderately, their coalescence proceeds faster and the sub-satellite is prone to form and relatively larger.

  4. Why arthroscopic partial meniscectomy?

    PubMed

    Lyu, Shaw-Ruey

    2015-09-01

    "Arthroscopic Partial Meniscectomy versus Sham Surgery for a Degenerative Meniscal Tear" published in the New England Journal of Medicine on December 26, 2013 draws the conclusion that arthroscopic partial medial meniscectomy provides no significant benefit over sham surgery in patients with a degenerative meniscal tear and no knee osteoarthritis. This result argues against the current practice of performing arthroscopic partial meniscectomy (APM) in patients with a degenerative meniscal tear. Since the number of APM performed has been increasing, the information provided by this study should lead to a change in clinical care of patients with a degenerative meniscus tear. PMID:26488013

  5. Electron Impact Ionization of C_2F_6

    NASA Astrophysics Data System (ADS)

    Iga, Ione; Pereira Sanches, Ivana; Srivastava, Santosh Kumar

    2001-10-01

    Besides CF_4, perfluoroethane, C_2F_6, is also one of the fluorocarbon compounds most frequently used in plasma processing applications. Consequently, the knowledge of the ionization properties of C_2F6 is clearly of interest in order to model the plasma-chemical reactions. Nevertheless, only few partial ionization-cross-section measurements [1,2] for this molecule were reported in the literature. Also, the energy range covered in these studies was very limited (below 120 eV). Recently, we have studied these properties. More specifically, partial ionization cross sections (PICS) for the fragments: C^+, F^+, CF^+, CF_2^+, CF_3^+ and C_2F_5^+, produced by electron impact on C_2F_6, were measured in a single-collision condition from near ionization threshold to 1000 eV. In addition, total ionization cross sections (TICS) are also obtained by summing up the PICS's. The comparison of our measured PICS and derived TICS with available data [1-4] will be presented during the Conference. [1] H. U. Poll, J. Meischner, Contrib. Plasma Phys. 27 (1987) 359. [2] C. Q. Jiao, A Garscadden, P. D. Haaland, Chem. Phys. Lett. 310 (1999) 52. [3] H. Nishimura, W. M. Huo, M. A Ali and Y -K. Kim, J. Chem. Phys. 110 (1999) 3811. [4] L. G. Christophorou and J. K. Olthoff, J. Phys. Chem. Ref. Data 27 (1998) 1 and references therein.

  6. Gridded electron reversal ionizer

    NASA Technical Reports Server (NTRS)

    Chutjian, Ara (Inventor)

    1993-01-01

    A gridded electron reversal ionizer forms a three dimensional cloud of zero or near-zero energy electrons in a cavity within a filament structure surrounding a central electrode having holes through which the sample gas, at reduced pressure, enters an elongated reversal volume. The resultant negative ion stream is applied to a mass analyzer. The reduced electron and ion space-charge limitations of this configuration enhances detection sensitivity for material to be detected by electron attachment, such as narcotic and explosive vapors. Positive ions may be generated by generating electrons having a higher energy, sufficient to ionize the target gas and pulsing the grid negative to stop the electron flow and pulsing the extraction aperture positive to draw out the positive ions.

  7. Electrospray Ionization Mass Spectrometry

    SciTech Connect

    Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

    2014-06-13

    Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

  8. Correlation in double ionization of He by ultrashort pulses

    NASA Astrophysics Data System (ADS)

    Feist, Johannes

    2008-05-01

    Double ionization of helium has long been of considerable interest in atomic physics since it provides insight into the role of electronic correlation in the full three-body Coulomb break-up process, which is of fundamental importance for the understanding of the dynamics in more complex atoms. The recent availability of attosecond XUV pulses allows to directly probe and possibly control the temporal structure of the ionization process. We have implemented an ab initio simulation of the interaction of ultrashort laser pulses with a helium atom. The wave function is represented in a time-dependent close- coupling (TDCC) scheme and time integration is performed utilizing the Arnoldi-Lanczos method. The spatial discretization employs an FEDVR basis, which lends itself to effective parallelization. We will present results on two-photon double ionization of He by ultrashort pulses over a wide range of photon energies. At low energies only non-sequential double ionization is possible (where both electrons share the energy of the photons, and consequently have to be ionized within a short period). For photon energies above 54.4,V (the ionization potential of the He^+ ground state), sequential double ionization is allowed. This process proceeds in two steps -- single ionization of He followed by ionization of the remaining He^+ ion. By using attosecond XUV pulses, these two separated stages of the sequential process are confined to within a short time interval of each other. We show that the angular distributions of the emitted electrons reveal the signature of a non-sequential process under the condition that sufficiently short pulses are used, while for longer pulses the sequential process completely dominates. The correlation time for double ionization can thus be directly observed using attosecond XUV pulses. This work was performed in collaboration with S. Nagele, R. Pazourek, E. Persson, B. I. Schneider, L. A. Collins, and J. Burgd"orfer.

  9. Electron-Atom Ionization Calculations using Propagating Exterior Complex Scaling

    NASA Astrophysics Data System (ADS)

    Bartlett, Philip

    2007-10-01

    The exterior complex scaling method (Science 286 (1999) 2474), pioneered by Rescigno, McCurdy and coworkers, provided highly accurate ab initio solutions for electron-hydrogen collisions by directly solving the time-independent Schr"odinger equation in coordinate space. An extension of this method, propagating exterior complex scaling (PECS), was developed by Bartlett and Stelbovics (J. Phys. B 37 (2004) L69, J. Phys. B 39 (2006) R379) and has been demonstrated to provide computationally efficient and accurate calculations of ionization and scattering cross sections over a large range of energies below, above and near the ionization threshold. An overview of the PECS method for three-body collisions and the computational advantages of its propagation and iterative coupling techniques will be presented along with results of: (1) near-threshold ionization of electron-hydrogen collisions and the Wannier threshold laws, (2) scattering cross section resonances below the ionization threshold, and (3) total and differential cross sections for electron collisions with excited targets and hydrogenic ions from low through to high energies. Recently, the PECS method has been extended to solve four-body collisions using time-independent methods in coordinate space and has initially been applied to the s-wave model for electron-helium collisions. A description of the extensions made to the PECS method to facilitate these significantly more computationally demanding calculations will be given, and results will be presented for elastic, single-excitation, double-excitation, single-ionization and double-ionization collisions.

  10. CT -- Body

    MedlinePlus

    ... News Physician Resources Professions Site Index A-Z Computed Tomography (CT) - Body Computed tomography (CT) of the body uses special x-ray ... Body? What is CT Scanning of the Body? Computed tomography, more commonly known as a CT or CAT ...

  11. Partial knee replacement - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series To use the sharing features on ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  12. Partial knee replacement

    MedlinePlus

    Most people recover quickly and have much less pain than they did before surgery. People who have a partial knee replacement recover faster than those who have a total knee replacement. Many people are able to walk ...

  13. Twisted partially pure spinors

    NASA Astrophysics Data System (ADS)

    Herrera, Rafael; Tellez, Ivan

    2016-08-01

    Motivated by the relationship between orthogonal complex structures and pure spinors, we define twisted partially pure spinors in order to characterize spinorially subspaces of Euclidean space endowed with a complex structure.

  14. Direct analysis of large living organism by megavolt electrostatic ionization mass spectrometry.

    PubMed

    Ng, Kwan-Ming; Tang, Ho-Wai; Man, Sin-Heng; Mak, Pui-Yuk; Choi, Yi-Ching; Wong, Melody Yee-Man

    2014-09-01

    A new ambient ionization method allowing the direct chemical analysis of living human body by mass spectrometry (MS) was developed. This MS method, namely Megavolt Electrostatic Ionization Mass Spectrometry, is based on electrostatic charging of a living individual to megavolt (MV) potential, illicit drugs, and explosives on skin/glove, flammable solvent on cloth/tissue paper, and volatile food substances in breath were readily ionized and detected by a mass spectrometer. PMID:24924518

  15. Direct Analysis of Large Living Organism by Megavolt Electrostatic Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ng, Kwan-Ming; Tang, Ho-Wai; Man, Sin-Heng; Mak, Pui-Yuk; Choi, Yi-Ching; Wong, Melody Yee-Man

    2014-09-01

    A new ambient ionization method allowing the direct chemical analysis of living human body by mass spectrometry (MS) was developed. This MS method, namely Megavolt Electrostatic Ionization Mass Spectrometry, is based on electrostatic charging of a living individual to megavolt (MV) potential, illicit drugs, and explosives on skin/glove, flammable solvent on cloth/tissue paper, and volatile food substances in breath were readily ionized and detected by a mass spectrometer.

  16. Continuous flow-extractive desorption electrospray ionization: analysis from "non-electrospray ionization-friendly" solvents and related mechanism.

    PubMed

    Li, Li; Yang, Samuel H; Lemr, Karel; Havlicek, Vladimir; Schug, Kevin A

    2013-03-26

    Due to their low polarities and dielectric constants, analytes in solvents such as hexane, chloroform, and ethyl acetate exhibit poor electrospray ionization (ESI) efficiency. These are deemed to be "non-ESI-friendly" solvents. Continuous flow extractive desorption electrospray ionization (CF-EDESI) is a novel ambient ionization technique that was recently developed in our group to manipulate protein charge distributions. Here we demonstrate its potential for ionizing analytes from non-ESI-friendly solvents. This feature makes CF-EDESI attractive to the general analytical community due to its apparent potential in lipidomics, normal phase separations, and hyphenation of mass spectrometry with HPLC-NMR systems. In this context, interest was subsequently initiated to discern mechanistic aspects of CF-EDESI. To achieve this, mechanistic experiments associated with a seemingly similar ambient ionization technique, extractive electrospray ionization (EESI), were emulated to compare CF-EDESI and EESI. Analysis of a series of fatty acids in multiple solvents in the negative ionization mode revealed differences between the two techniques. Whereas EESI has been previously shown to operate via extraction of analytes into the spray solvent, data presented here for CF-EDESI point toward a liquid-liquid mixing process to facilitate ionization. Further, a partial factorial design experiment was performed to evaluate the effects of different experimental variables on signal intensity. Sample flow rate was confirmed to be among the most significant factors to affect sensitivity. As a whole, the work presented provides greater insight into a new ambient ionization process, which exhibits expanded capabilities over conventional ESI; in this case, for direct analysis from non-ESI-friendly solvents. PMID:23498125

  17. PARTIAL TORUS INSTABILITY

    SciTech Connect

    Olmedo, Oscar; Zhang Jie

    2010-07-20

    Flux ropes are now generally accepted to be the magnetic configuration of coronal mass ejections (CMEs), which may be formed prior to or during solar eruptions. In this study, we model the flux rope as a current-carrying partial torus loop with its two footpoints anchored in the photosphere, and investigate its stability in the context of the torus instability (TI). Previous studies on TI have focused on the configuration of a circular torus and revealed the existence of a critical decay index of the overlying constraining magnetic field. Our study reveals that the critical index is a function of the fractional number of the partial torus, defined by the ratio between the arc length of the partial torus above the photosphere and the circumference of a circular torus of equal radius. We refer to this finding as the partial torus instability (PTI). It is found that a partial torus with a smaller fractional number has a smaller critical index, thus requiring a more gradually decreasing magnetic field to stabilize the flux rope. On the other hand, a partial torus with a larger fractional number has a larger critical index. In the limit of a circular torus when the fractional number approaches 1, the critical index goes to a maximum value. We demonstrate that the PTI helps us to understand the confinement, growth, and eventual eruption of a flux-rope CME.

  18. A device for determining the intensity of partial sweating

    NASA Technical Reports Server (NTRS)

    Rayskiy, V. A.; Vinogradov, Y. A.; Safonov, O. A.

    1979-01-01

    An invention which can measure partial perspiration is disclosed. The partial perspiration is measured with a specially shaped device tightly fastened to the body but not touching the skin area being studied. A special grid is used to keep the moisture-absorbing agent from touching the skin.

  19. Partial thromboplastin time (PTT)

    MedlinePlus

    ... which there is a problem with the body's blood clotting process Disorder in which the proteins that control blood clotting become over active ( disseminated intravascular coagulation ) Liver disease ...

  20. THE ESCAPE FRACTION OF IONIZING RADIATION FROM GALAXIES

    SciTech Connect

    Benson, Andrew; Venkatesan, Aparna; Shull, J. Michael E-mail: avenkatesan@usfca.edu

    2013-06-10

    The escape of ionizing radiation from galaxies plays a critical role in the evolution of gas in galaxies, and the heating and ionization history of the intergalactic medium. We present semi-analytic calculations of the escape fraction of ionizing radiation for both hydrogen and helium from galaxies ranging from primordial systems to disk-type galaxies that are not heavily dust-obscured. We consider variations in the galaxy density profile, source type, location, and spectrum, and gas overdensity/distribution factors. For sufficiently hard first-light sources, the helium ionization fronts closely track or advance beyond that of hydrogen. Key new results in this work include calculations of the escape fractions for He I and He II ionizing radiation, and the impact of partial ionization from X-rays from early active galactic nuclei or stellar clusters on the escape fractions from galaxy halos. When factoring in frequency-dependent effects, we find that X-rays play an important role in boosting the escape fractions for both hydrogen and helium, but especially for He II. We briefly discuss the implications of these results for recent observations of the He II reionization epoch at low redshifts, as well as the UV data and emission-line signatures from early galaxies anticipated from future satellite missions.

  1. Measurement of partial pressures in vacuum technology and vacuum physics

    NASA Technical Reports Server (NTRS)

    Huber, W. K.

    1986-01-01

    It is pointed out that the measurement of gaseous pressures of less than 0.0001 torr is based on the ionization of gas atoms and molecules due to collisions with electrons. The particle density is determined in place of the pressure. The ionization cross sections for molecules of various gases are discussed. It is found that the true pressure in a vacuum system cannot be determined with certainty if it is unknown which gas is present. Effects of partial pressure determination on the condition of the vacuum system are discussed together with ion sources, systems of separation, and ion detection.

  2. Partial gravity - Human impacts on facility design

    NASA Technical Reports Server (NTRS)

    Capps, Stephen; Moore, Nathan

    1990-01-01

    Partial gravity affects the body differently than earth gravity and microgravity environments. The main difference from earth gravity is human locomotion; while the main dfference from microgravity is the specific updown orientation and reach envelopes which increase volume requirements. Much data are available on earth gravity and microgravity design; however, very little information is available on human reactions to reduced gravity levels in IVA situations (without pressure suits). Therefore, if humans commit to permanent lunar habitation, much research should be conducted in the area of partial gravity effects on habitat design.

  3. Ionization of polarized hydrogen atoms

    SciTech Connect

    Alessi, J.G.

    1983-01-01

    Methods are discussed for the production of polarized H/sup -/ ions from polarized atoms produced in ground state atomic beam sources. Present day sources use ionizers of two basic types - electron ionizers for H/sup +/ Vector production followed by double charge exchange in a vapor, or direct H/sup -/ Vector production by charge exchange of H/sup 0/ with Cs/sup 0/. Both methods have ionization efficiencies of less than 0.5%. Ionization efficiencies in excess of 10% may be obtained in the future by the use of a plasma ionizer plus charge exchange in Cs or Sr vapor, or ionization by resonant charge exchange with a self-extracted D/sup -/ beam from a ring magnetron or HCD source. 36 references, 4 figures.

  4. Plasma Production via Field Ionization

    SciTech Connect

    O'Connell, C.L.; Barnes, C.D.; Decker, F.; Hogan, M.J.; Iverson, R.; Krejcik, P.; Siemann, R.; Walz, D.R.; Clayton, C.E.; Huang, C.; Johnson, D.K.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Zhou, M.; Deng, S.; Katsouleas, T.; Muggli, P.; Oz, E.; /Southern California U.

    2007-01-02

    Plasma production via field ionization occurs when an incoming particle beam is sufficiently dense that the electric field associated with the beam ionizes a neutral vapor or gas. Experiments conducted at the Stanford Linear Accelerator Center explore the threshold conditions necessary to induce field ionization by an electron beam in a neutral lithium vapor. By independently varying the transverse beam size, number of electrons per bunch or bunch length, the radial component of the electric field is controlled to be above or below the threshold for field ionization. Additional experiments ionized neutral xenon and neutral nitric oxide by varying the incoming beam's bunch length. A self-ionized plasma is an essential step for the viability of plasma-based accelerators for future high-energy experiments.

  5. Partial spread OFDM

    NASA Astrophysics Data System (ADS)

    Elghariani, Ali; Zoltowski, Michael D.

    2012-05-01

    In this paper, partial spread OFDM system has been presented and its performance has been studied when different detection techniques are employed, such as minimum mean square error (MMSE), grouped Maximum Likelihood (ML) and approximated integer quadratic programming (IQP) techniques . The performance study also includes applying two different spreading matrices, Hadamard and Vandermonde. Extensive computer simulation have been implemented and important results show that partial spread OFDM system improves the BER performance and the frequency diversity of OFDM compared to both non spread and full spread systems. The results from this paper also show that partial spreading technique combined with suboptimal detector could be a better solution for applications that require low receiver complexity and high information detectability.

  6. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-17

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  7. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    1999-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  8. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, Shabbir; Kumar, Romesh; Krumpelt, Michael

    2001-01-01

    A partial oxidation reformer comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell.

  9. Methanol partial oxidation reformer

    DOEpatents

    Ahmed, S.; Kumar, R.; Krumpelt, M.

    1999-08-24

    A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

  10. Oxygen partial pressure sensor

    DOEpatents

    Dees, D.W.

    1994-09-06

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.

  11. Oxygen partial pressure sensor

    DOEpatents

    Dees, Dennis W.

    1994-01-01

    A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.

  12. Body Measurement.

    ERIC Educational Resources Information Center

    Neufeld, K. Allen

    1989-01-01

    Described are activities for measuring the human body. The activities include measurements and calculations, calculating volume and density, problems related to body measurement, and using a nomogram. Several charts, illustrations, and a nomogram are provided. (YP)

  13. Radiation-enhanced gate-induced-drain-leakage current in the 130 nm partially-depleted SOI pMOSFET

    NASA Astrophysics Data System (ADS)

    Peng, Chao; Hu, Zhiyuan; Ning, Bingxu; Dai, Lihua; Bi, Dawei; Zhang, Zhengxuan

    2015-04-01

    The total ionizing dose (TID) effect of the pMOSFET from 130 nm partially-depleted silicon-on-insulator (PDSOI) is investigated. The data obtained from 60Co γ-ray irradiation experiments indicate that input/output (I/O) device is more susceptible to TID effect than the core device. An anomalous off-state leakage increase is observed for I/O pMOSFET when drain is biased at a high voltage after irradiation. It is proved that this radiation-induced leakage relates to the enhanced gate-induce-drain-leakage (GIDL). Both the radiation-induced interface traps at the gate-oxide/body interface and the oxide trapped charges in the buried oxide (BOX) are responsible for the growth of the leakage current. These conclusions are also verified by the TCAD simulations. The isothermal annealing can recover the leakage current to the pre-irradiation level.

  14. The Phobos neutral and ionized torus

    NASA Astrophysics Data System (ADS)

    Poppe, A. R.; Curry, S. M.; Fatemi, S.

    2016-05-01

    Charged particle sputtering, micrometeoroid impact vaporization, and photon-stimulated desorption are fundamental processes operating at airless surfaces throughout the solar system. At larger bodies, such as Earth's Moon and several of the outer planet moons, these processes generate tenuous surface-bound exospheres that have been observed by a variety of methods. Phobos and Deimos, in contrast, are too gravitationally weak to keep ejected neutrals bound and, thus, are suspected to generate neutral tori in orbit around Mars. While these tori have not yet been detected, the distribution and density of both the neutral and ionized components are of fundamental interest. We combine a neutral Monte Carlo model and a hybrid plasma model to investigate both the neutral and ionized components of the Phobos torus. We show that the spatial distribution of the neutral torus is highly dependent on each individual species (due to ionization rates that span nearly 4 orders of magnitude) and on the location of Phobos with respect to Mars. Additionally, we present the flux distribution of torus pickup ions throughout the Martian system and estimate typical pickup ion fluxes. We find that the predicted pickup ion fluxes are too low to perturb the ambient plasma, consistent with previous null detections by spacecraft around Mars.

  15. Nonsequential double ionization of molecules

    SciTech Connect

    Prauzner-Bechcicki, Jakub S.; Sacha, Krzysztof; Zakrzewski, Jakub; Eckhardt, Bruno

    2005-03-01

    Double ionization of diatomic molecules by short linearly polarized laser pulses is analyzed. We consider the final stage of the ionization process, that is the decay of a highly excited two electron molecule, which is formed after rescattering. The saddles of the effective adiabatic potential energy close to which simultaneous escape of electrons takes place are identified. Numerical simulations of the ionization of molecules show that the process can be dominated by either sequential or nonsequential events. In order to increase the ratio of nonsequential to sequential ionizations very short laser pulses should be applied.

  16. Ionization Processes in the Atmosphere of Titan (Research Note). III. Ionization by High-Z Nuclei Cosmic Rays

    NASA Technical Reports Server (NTRS)

    Gronoff, G.; Mertens, C.; Lilensten, J.; Desorgher, L.; Fluckiger, E.; Velinov, P.

    2011-01-01

    Context. The Cassini-Huygens mission has revealed the importance of particle precipitation in the atmosphere of Titan thanks to in-situ measurements. These ionizing particles (electrons, protons, and cosmic rays) have a strong impact on the chemistry, hence must be modeled. Aims. We revisit our computation of ionization in the atmosphere of Titan by cosmic rays. The high-energy high-mass ions are taken into account to improve the precision of the calculation of the ion production profile. Methods. The Badhwahr and O Neill model for cosmic ray spectrum was adapted for the Titan model. We used the TransTitan model coupled with the Planetocosmics model to compute the ion production by cosmic rays. We compared the results with the NAIRAS/HZETRN ionization model used for the first time for a body that differs from the Earth. Results. The cosmic ray ionization is computed for five groups of cosmic rays, depending on their charge and mass: protons, alpha, Z = 8 (oxygen), Z = 14 (silicon), and Z = 26 (iron) nucleus. Protons and alpha particles ionize mainly at 65 km altitude, while the higher mass nucleons ionize at higher altitudes. Nevertheless, the ionization at higher altitude is insufficient to obscure the impact of Saturn s magnetosphere protons at a 500 km altitude. The ionization rate at the peak (altitude: 65 km, for all the different conditions) lies between 30 and 40/cu cm/s. Conclusions. These new computations show for the first time the importance of high Z cosmic rays on the ionization of the Titan atmosphere. The updated full ionization profile shape does not differ significantly from that found in our previous calculations (Paper I: Gronoff et al. 2009, 506, 955) but undergoes a strong increase in intensity below an altitude of 400 km, especially between 200 and 400 km altitude where alpha and heavier particles (in the cosmic ray spectrum) are responsible for 40% of the ionization. The comparison of several models of ionization and cosmic ray spectra (in

  17. Associative ionization reactions involving excited atoms in nitrogen plasma

    SciTech Connect

    Popov, N. A.

    2009-05-15

    A model of kinetic processes in gas-discharge plasmas of pure nitrogen and its mixtures with nitrogen oxide and oxygen is presented. A distinctive feature of the model is that it includes associative ionization reactions involving N({sup 2}P) electronically excited atoms. Taking into account these processes allows one to explain both the anomalously slow decay of gas-discharge nitrogen plasma and the increase in the electron density in the region of the so-called pink afterglow in nitrogen. The possibility of substantially accelerating secondary ionization by adding NO molecules to a partially dissociated nitrogen is demonstrated. It is shown that such acceleration is caused by the associative ionization reaction N({sup 2}P) + O({sup 3}P) {yields} e + NO{sup +}. The calculated results agree well with available experimental data.

  18. Theoretical studies of photoexcitation and ionization in H2O

    NASA Technical Reports Server (NTRS)

    Diercksen, G. H. F.; Kraemer, W. P.; Rescigno, T. N.; Bender, C. F.; Mckoy, B. V.; Langhoff, S. R.; Langhoff, P. W.

    1982-01-01

    Theoretical studies using Franck-Condon and static-exchange approximations are reported for the complete dipole excitation and ionization spectrum in H2O, where (1) large Cartesian Gaussian basis sets are used to represent the required discrete and continuum electronic eigenfunctions at the ground state equilibrium geometry, and (2) previously devised moment-theory techniques are employed in constructing the continuum oscillator-strength densities from the calculated spectra. Comparisons are made of the calculated excitation and ionization profiles with recent experimental photoabsorption studies and corresponding spectral assignments, electron impact-excitation cross sections, and dipole and synchrotron-radiation studies of partial-channel photoionization cross sections. The calculated partial-channel cross sections are found to be atomic-like, and dominated by 2p-kd components. It is suggested that the latter transition couples with the underlying 1b(1)-kb(1) channel, accounting for a prominent feature in recent synchrotron-radiation measurements.

  19. Virtual environment application with partial gravity simulation

    NASA Technical Reports Server (NTRS)

    Ray, David M.; Vanchau, Michael N.

    1994-01-01

    To support manned missions to the surface of Mars and missions requiring manipulation of payloads and locomotion in space, a training facility is required to simulate the conditions of both partial and microgravity. A partial gravity simulator (Pogo) which uses pneumatic suspension is being studied for use in virtual reality training. Pogo maintains a constant partial gravity simulation with a variation of simulated body force between 2.2 and 10 percent, depending on the type of locomotion inputs. this paper is based on the concept and application of a virtual environment system with Pogo including a head-mounted display and glove. The reality engine consists of a high end SGI workstation and PC's which drive Pogo's sensors and data acquisition hardware used for tracking and control. The tracking system is a hybrid of magnetic and optical trackers integrated for this application.

  20. Partial Participation Revisited.

    ERIC Educational Resources Information Center

    Ferguson, Dianne L.; Baumgart, Diane

    1991-01-01

    This article reanalyzes the principle of partial participation in integrated educational programing for students with severe or profound disabilities. The article presents four "error patterns" in how the concept has been used, some reasons why such error patterns have occurred, and strategies for avoiding these errors. (Author/JDD)

  1. Partial gravity habitat study

    NASA Technical Reports Server (NTRS)

    Capps, Stephen; Lorandos, Jason; Akhidime, Eval; Bunch, Michael; Lund, Denise; Moore, Nathan; Murakawa, Kiosuke

    1989-01-01

    The purpose of this study is to investigate comprehensive design requirements associated with designing habitats for humans in a partial gravity environment, then to apply them to a lunar base design. Other potential sites for application include planetary surfaces such as Mars, variable-gravity research facilities, and a rotating spacecraft. Design requirements for partial gravity environments include locomotion changes in less than normal earth gravity; facility design issues, such as interior configuration, module diameter, and geometry; and volumetric requirements based on the previous as well as psychological issues involved in prolonged isolation. For application to a lunar base, it is necessary to study the exterior architecture and configuration to insure optimum circulation patterns while providing dual egress; radiation protection issues are addressed to provide a safe and healthy environment for the crew; and finally, the overall site is studied to locate all associated facilities in context with the habitat. Mission planning is not the purpose of this study; therefore, a Lockheed scenario is used as an outline for the lunar base application, which is then modified to meet the project needs. The goal of this report is to formulate facts on human reactions to partial gravity environments, derive design requirements based on these facts, and apply the requirements to a partial gravity situation which, for this study, was a lunar base.

  2. [Effect of ionizing radiation on the living body].

    PubMed

    Kojima, Shuji

    2014-01-01

    Since the Fukushima nuclear plant accident following the great East Japan earthquake on March 11, 2011, we have been warned to be careful about possible radiation exposure almost every day in newspapers and on TV. Radioactive iodine ((131)I) and cesium ((134)Cs, (137)Cs) produced by nuclear reactions were released into the air during and after the accident, and have been scattered by the winds in Tohoku and in the Kanto district. Even today, 2 years after the accident, there is great public concern about possible pollution of foodstuffs and fishery products with radioactive cesium, not only in Japan, but also in other countries. On the other hand, decontamination work has been proceeding, including removal of contaminated soil near the accident site. Since the accident, many media reports have continued to tell us only that current dose levels of radiation are not dangerous to human health. But, many people are not satisfied with such vague statements, and want to understand the situation in more detail. So, it is important to provide basic education about the effects of radiation to the general public. I am a professor of the Department of Radiation Biosciences at Tokyo University of Science, and so I am very familiar with radiation and its dangers. So, in my lecture today, we would like to explain the effects of radiation and put the present situation into perspective, so that people will better understand the risks, and not be unnecessarily afraid. PMID:24492216

  3. Ionizing radiation detector

    DOEpatents

    Thacker, Louis H.

    1990-01-01

    An ionizing radiation detector is provided which is based on the principle of analog electronic integration of radiation sensor currents in the sub-pico to nano ampere range between fixed voltage switching thresholds with automatic voltage reversal each time the appropriate threshold is reached. The thresholds are provided by a first NAND gate Schmitt trigger which is coupled with a second NAND gate Schmitt trigger operating in an alternate switching state from the first gate to turn either a visible or audible indicating device on and off in response to the gate switching rate which is indicative of the level of radiation being sensed. The detector can be configured as a small, personal radiation dosimeter which is simple to operate and responsive over a dynamic range of at least 0.01 to 1000 R/hr.

  4. Ionized cluster beam deposition

    NASA Technical Reports Server (NTRS)

    Kirkpatrick, A. R.

    1983-01-01

    Ionized Cluster Beam (ICB) deposition, a new technique originated by Takagi of Kyoto University in Japan, offers a number of unique capabilities for thin film metallization as well as for deposition of active semiconductor materials. ICB allows average energy per deposited atom to be controlled and involves impact kinetics which result in high diffusion energies of atoms on the growth surface. To a greater degree than in other techniques, ICB involves quantitative process parameters which can be utilized to strongly control the characteristics of films being deposited. In the ICB deposition process, material to be deposited is vaporized into a vacuum chamber from a confinement crucible at high temperature. Crucible nozzle configuration and operating temperature are such that emerging vapor undergoes supercondensation following adiabatic expansion through the nozzle.

  5. Amorphous silicon ionizing particle detectors

    DOEpatents

    Street, R.A.; Mendez, V.P.; Kaplan, S.N.

    1988-11-15

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation. 15 figs.

  6. Amorphous silicon ionizing particle detectors

    DOEpatents

    Street, Robert A.; Mendez, Victor P.; Kaplan, Selig N.

    1988-01-01

    Amorphous silicon ionizing particle detectors having a hydrogenated amorphous silicon (a--Si:H) thin film deposited via plasma assisted chemical vapor deposition techniques are utilized to detect the presence, position and counting of high energy ionizing particles, such as electrons, x-rays, alpha particles, beta particles and gamma radiation.

  7. Performance deficit produced by partial body exposures to space radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    On exploratory class missions to other planets, astronauts will be exposed to types of radiation (particles of high energy and charge [HZE particles]) that are not experienced in low earth orbit, where the space shuttle operates. Previous research has shown that exposure to HZE particles can affect...

  8. Ionization detection system for aerosols

    DOEpatents

    Jacobs, Martin E.

    1977-01-01

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system utilizes a measuring ionization chamber which is modified to minimize false alarms and reductions in sensitivity resulting from changes in ambient temperature. In the preferred form of the modification, an annular radiation shield is mounted about the usual radiation source provided to effect ionization in the measuring chamber. The shield is supported by a bimetallic strip which flexes in response to changes in ambient temperature, moving the shield relative to the source so as to vary the radiative area of the source in a manner offsetting temperature-induced variations in the sensitivity of the chamber.

  9. Partially coherent ultrafast spectrography

    NASA Astrophysics Data System (ADS)

    Bourassin-Bouchet, C.; Couprie, M.-E.

    2015-03-01

    Modern ultrafast metrology relies on the postulate that the pulse to be measured is fully coherent, that is, that it can be completely described by its spectrum and spectral phase. However, synthesizing fully coherent pulses is not always possible in practice, especially in the domain of emerging ultrashort X-ray sources where temporal metrology is strongly needed. Here we demonstrate how frequency-resolved optical gating (FROG), the first and one of the most widespread techniques for pulse characterization, can be adapted to measure partially coherent pulses even down to the attosecond timescale. No modification of experimental apparatuses is required; only the processing of the measurement changes. To do so, we take our inspiration from other branches of physics where partial coherence is routinely dealt with, such as quantum optics and coherent diffractive imaging. This will have important and immediate applications, such as enabling the measurement of X-ray free-electron laser pulses despite timing jitter.

  10. Partially integrated exhaust manifold

    DOEpatents

    Hayman, Alan W; Baker, Rodney E

    2015-01-20

    A partially integrated manifold assembly is disclosed which improves performance, reduces cost and provides efficient packaging of engine components. The partially integrated manifold assembly includes a first leg extending from a first port and terminating at a mounting flange for an exhaust gas control valve. Multiple additional legs (depending on the total number of cylinders) are integrally formed with the cylinder head assembly and extend from the ports of the associated cylinder and terminate at an exit port flange. These additional legs are longer than the first leg such that the exit port flange is spaced apart from the mounting flange. This configuration provides increased packaging space adjacent the first leg for any valving that may be required to control the direction and destination of exhaust flow in recirculation to an EGR valve or downstream to a catalytic converter.

  11. Partially coherent ultrafast spectrography

    PubMed Central

    Bourassin-Bouchet, C.; Couprie, M.-E.

    2015-01-01

    Modern ultrafast metrology relies on the postulate that the pulse to be measured is fully coherent, that is, that it can be completely described by its spectrum and spectral phase. However, synthesizing fully coherent pulses is not always possible in practice, especially in the domain of emerging ultrashort X-ray sources where temporal metrology is strongly needed. Here we demonstrate how frequency-resolved optical gating (FROG), the first and one of the most widespread techniques for pulse characterization, can be adapted to measure partially coherent pulses even down to the attosecond timescale. No modification of experimental apparatuses is required; only the processing of the measurement changes. To do so, we take our inspiration from other branches of physics where partial coherence is routinely dealt with, such as quantum optics and coherent diffractive imaging. This will have important and immediate applications, such as enabling the measurement of X-ray free-electron laser pulses despite timing jitter. PMID:25744080

  12. Partial quantum logics revisited

    NASA Astrophysics Data System (ADS)

    Vetterlein, Thomas

    2011-01-01

    Partial Boolean algebras (PBAs) were introduced by Kochen and Specker as an algebraic model reflecting the mutual relationships among quantum-physical yes-no tests. The fact that not all pairs of tests are compatible was taken into special account. In this paper, we review PBAs from two sides. First, we generalise the concept, taking into account also those yes-no tests which are based on unsharp measurements. Namely, we introduce partial MV-algebras, and we define a corresponding logic. Second, we turn to the representation theory of PBAs. In analogy to the case of orthomodular lattices, we give conditions for a PBA to be isomorphic to the PBA of closed subspaces of a complex Hilbert space. Hereby, we do not restrict ourselves to purely algebraic statements; we rather give preference to conditions involving automorphisms of a PBA. We conclude by outlining a critical view on the logico-algebraic approach to the foundational problem of quantum physics.

  13. Invariant criteria for bound states, degree of ionization, and plasma phase transition

    NASA Technical Reports Server (NTRS)

    Girardeau, M. D.

    1990-01-01

    Basis invariant characterizations of bound states and bound fraction of a partially ionized hydrogen plasma are given in terms of properties of the spectrum of eigenvalues and eigenfunctions of the equilibrium quantum statistical one-proton-one-electron reduced density matrix. It is suggested that these can be used to place theories of a proposed plasma-ionization phase transition on a firm foundation. This general approach may be relevant to cosmological questions such as the quark deconfinement-confinement transition.

  14. Body Piercing

    PubMed Central

    Koenig, Laura M; Carnes, Molly

    1999-01-01

    OBJECTIVE To review the current information on medical complications, psychological implications, and legislative issues related to body piercing, a largely unregulated industry in the United States. METHODS We conducted a MEDLINE search of English language articles from 1966 until May 1998 using the search terms “body piercing” and “ear piercing.” Bibliographies of these references were reviewed for additional citations. We also conducted an Internet search for “body piercing” on the World Wide Web. MAIN RESULTS: In this manuscript, we review the available body piercing literature. We conclude that body piercing is an increasingly common practice in the United States, that this practice carries substantial risk of morbidity, and that most body piercing in the United States is being performed by unlicensed, unregulated individuals. Primary care physicians are seeing growing numbers of patients with body pierces. Practitioners must be able to recognize, treat, and counsel patients on body piercing complications and be alert to associated psychological conditions in patients who undergo body piercing. PMID:10354260

  15. IEHI: Ionization Equilibrium for Heavy Ions

    NASA Astrophysics Data System (ADS)

    Cranmer, Steven R.

    2015-07-01

    IEHI, written in Fortran, outputs a simple "coronal" ionization equilibrium (i.e., collisional ionization and auto-ionization balanced by radiative and dielectronic recombination) for a plasma at a given electron temperature.

  16. Magnetic reconnection in a weakly ionized plasma

    SciTech Connect

    Leake, James E.; Lukin, Vyacheslav S.; Linton, Mark G.

    2013-06-15

    Magnetic reconnection in partially ionized plasmas is a ubiquitous phenomenon spanning the range from laboratory to intergalactic scales, yet it remains poorly understood and relatively little studied. Here, we present results from a self-consistent multi-fluid simulation of magnetic reconnection in a weakly ionized reacting plasma with a particular focus on the parameter regime of the solar chromosphere. The numerical model includes collisional transport, interaction and reactions between the species, and optically thin radiative losses. This model improves upon our previous work in Leake et al.[“Multi-fluid simulations of chromospheric magnetic reconnection in a weakly ionized reacting plasma,” Astrophys. J. 760, 109 (2012)] by considering realistic chromospheric transport coefficients, and by solving a generalized Ohm's law that accounts for finite ion-inertia and electron-neutral drag. We find that during the two dimensional reconnection of a Harris current sheet with an initial width larger than the neutral-ion collisional coupling scale, the current sheet thins until its width becomes less than this coupling scale, and the neutral and ion fluids decouple upstream from the reconnection site. During this process of decoupling, we observe reconnection faster than the single-fluid Sweet-Parker prediction, with recombination and plasma outflow both playing a role in determining the reconnection rate. As the current sheet thins further and elongates, it becomes unstable to the secondary tearing instability, and plasmoids are seen. The reconnection rate, outflows, and plasmoids observed in this simulation provide evidence that magnetic reconnection in the chromosphere could be responsible for jet-like transient phenomena such as spicules and chromospheric jets.

  17. High pressure xenon ionization detector

    DOEpatents

    Markey, John K.

    1989-01-01

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0.degree. to 30.degree. C.

  18. High pressure xenon ionization detector

    DOEpatents

    Markey, J.K.

    1989-11-14

    A method is provided for detecting ionization comprising allowing particles that cause ionization to contact high pressure xenon maintained at or near its critical point and measuring the amount of ionization. An apparatus is provided for detecting ionization, the apparatus comprising a vessel containing a ionizable medium, the vessel having an inlet to allow high pressure ionizable medium to enter the vessel, a means to permit particles that cause ionization of the medium to enter the vessel, an anode, a cathode, a grid and a plurality of annular field shaping rings, the field shaping rings being electrically isolated from one another, the anode, cathode, grid and field shaping rings being electrically isolated from one another in order to form an electric field between the cathode and the anode, the electric field originating at the anode and terminating at the cathode, the grid being disposed between the cathode and the anode, the field shaping rings being disposed between the cathode and the grid, the improvement comprising the medium being xenon and the vessel being maintained at a pressure of 50 to 70 atmospheres and a temperature of 0 to 30 C. 2 figs.

  19. Body Basics

    MedlinePlus

    ... more about how the body works, what basic human anatomy is, and what happens when parts of the body don't function properly. Blood Bones, Muscles, and Joints Brain and Nervous System Digestive System Endocrine System Eyes Female Reproductive System ...

  20. Iron ionization and recombination rates and ionization equilibrium

    NASA Technical Reports Server (NTRS)

    Arnaud, M.; Raymond, J.

    1992-01-01

    In the past few years important progress has been made on the knowledge of ionization and recombination rates of iron, an astrophysically abundant heavy element and a major impurity in laboratory fusion devices. We make a critical review of the existing data on ionization and dielectronic recombination and present new computations of radiative recombination rate coefficients of Fe(+14) through Fe(+25) using the photoionization cross sections of Clark et al. (1986). We provide analytical fits to the recommended data (direct ionization and excitation-autoionization cross sections; radiative and dielectronic recombination rate coefficients). Finally we determine the iron ionic fractions at ionization equilibrium and compare them with previous computations as well as with observational data.

  1. The time-dependent generalized active space configuration interaction approach to correlated ionization dynamics of diatomic molecules

    NASA Astrophysics Data System (ADS)

    Bauch, S.; Larsson, H. R.; Hinz, C.; Bonitz, M.

    2016-03-01

    In this contribution, we review the time-dependent generalized-active-space configuration interaction (TD-GAS-CI) approach to the photoionization dynamics of atoms and molecules including electron correlation effects. It is based on the configuration interaction (CI) expansion of the many-body wave function and the restriction of the determinantal space to a reduced subspace. For its numerically efficient application to photoionization, a partially-rotated basis set is used which adopts features of a localized basis with a good reference description and a grid representation for escaping wave packets. After reviewing earlier applications of the theory, we address the strong-field ionization of a one-dimensional model of the four-electron LiH molecule using TD-GAS-CI and demonstrate the importance of electron-electron correlations in the ionization yield for different orientations of the molecule w.r.t the peak of the linearly polarized laser field. A pronounced orientation-dependent variation of the yield with the pulse duration and the level of considered electron-electron correlations is observed.

  2. Microwave reflectometer ionization sensor

    NASA Technical Reports Server (NTRS)

    Seals, Joseph; Fordham, Jeffrey A.; Pauley, Robert G.; Simonutti, Mario D.

    1993-01-01

    The development of the Microwave Reflectometer Ionization Sensor (MRIS) Instrument for use on the Aeroassist Flight Experiment (AFE) spacecraft is described. The instrument contract was terminated, due to cancellation of the AFE program, subsequent to testing of an engineering development model. The MRIS, a four-frequency reflectometer, was designed for the detection and location of critical electron density levels in spacecraft reentry plasmas. The instrument would sample the relative magnitude and phase of reflected signals at discrete frequency steps across 4 GHz bandwidths centered at four frequencies: 20, 44, 95, and 140 GHz. The sampled data would be stored for later processing to calculate the distance from the spacecraft surface to the critical electron densities versus time. Four stepped PM CW transmitter receivers were located behind the thermal protection system of the spacecraft with horn antennas radiating and receiving through an insulating tile. Techniques were developed to deal with interference, including multiple reflections and resonance effects, resulting from the antenna configuration and operating environment.

  3. Optical ionization detector

    DOEpatents

    Wuest, Craig R.; Lowry, Mark E.

    1994-01-01

    An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium.

  4. Optical ionization detector

    DOEpatents

    Wuest, C.R.; Lowry, M.E.

    1994-03-29

    An optical ionization detector wherein a beam of light is split so that one arm passes through a fiber optics and the other arm passes through a gas-filled region, and uses interferometry to detect density changes in a gas when charged particles pass through it. The gas-filled region of the detector is subjected to a high electric field and as a charged particle traverses this gas region electrons are freed from the cathode and accelerated so as to generate an electron avalanche which is collected on the anode. The gas density is effected by the electron avalanche formation and if the index or refraction is proportional to the gas density the index will change accordingly. The detector uses this index change by modulating the one arm of the split light beam passing through the gas, with respect to the other arm that is passed through the fiber optic. Upon recombining of the beams, interference fringe changes as a function of the index change indicates the passage of charged particles through the gaseous medium. 3 figures.

  5. Martian Meteor Ionization Layers

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Pesnell, W. D.

    1999-01-01

    Small interplanetary grains bombard Mars, like all the solar system planets, and, like all the planets with atmospheres, meteoric ion and atom layers form in the upper atmosphere. We have developed a comprehensive one-dimensional model of the Martian meteoric ionization layer including a full chemical scheme. A persistent layer of magnesium ions should exist around an altitude of 70 km. Unlike the terrestrial case, where the metallic ions are formed via charge-exchange with the ambient ions, Mg(+) in the Martian atmosphere is produced by photoionization. Nevertheless, the predicted metal layer peak densities for Earth and Mars are similar. Diffusion solutions, such as those presented here, should be a good approximation of the metallic ions in regions where the magnetic field is negligible and may provide a significant contribution to the nightside ionosphere. The low ultraviolet absorption of the Martian atmosphere may make Mars an excellent laboratory in which to study meteoric ablation. Resonance lines not seen in the spectra of terrestrial meteors may be visible to a surface observatory in the Martian highlands.

  6. Pulsed helium ionization detection system

    DOEpatents

    Ramsey, Roswitha S.; Todd, Richard A.

    1987-01-01

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  7. Pulsed helium ionization detection system

    DOEpatents

    Ramsey, R.S.; Todd, R.A.

    1985-04-09

    A helium ionization detection system is provided which produces stable operation of a conventional helium ionization detector while providing improved sensitivity and linearity. Stability is improved by applying pulsed dc supply voltage across the ionization detector, thereby modifying the sampling of the detectors output current. A unique pulse generator is used to supply pulsed dc to the detector which has variable width and interval adjust features that allows up to 500 V to be applied in pulse widths ranging from about 150 nsec to about dc conditions.

  8. Ionizing radiation promotes protozoan reproduction

    SciTech Connect

    Luckey, T.D.

    1986-11-01

    This experiment was performed to determine whether ionizing radiation is essential for maximum growth rate in a ciliated protozoan. When extraneous ionizing radiation was reduced to 0.15 mrad/day, the reproduction rate of Tetrahymena pyriformis was significantly less (P less than 0.01) than it was at near ambient levels, 0.5 or 1.8 mrad/day. Significantly higher growth rates (P less than 0.01) were obtained when chronic radiation was increased. The data suggest that ionizing radiation is essential for optimum reproduction rate in this organism.

  9. Ionization cross sections and rate coefficients for CFCl3 molecule by electron impact

    NASA Astrophysics Data System (ADS)

    Pal, Satyendra; Kumar, Neeraj

    2013-09-01

    Chlorofluorocarbons (CFCs) or freons are important industrial material with wide-ranging applications as refrigerant, aerosol propellant and semiconductor etchant, etc. The large-scale industrial consumption is of particular environmental concern because of its potential for ozone destruction in the stratosphere. The present work reports the calculations for differential cross sections as a function of secondary/ ejected electron energy and the scattering angle in the ionization of CFCl3 by electron collision leading to the production of various cations viz. CCl3+,CFCl2+,CCl2+,CFCl+, CCl+, Cl+, CF+, F+, and C+ through direct and dissociative ionization processes at a fixed incident electron energy of 200 eV. A modified Jain-Khare semi-empirical formalism based on oscillator strength has been employed. To the best of our knowledge, no experimental and/or theoretical data is available for comparison of the present results for differential cross sections. The corresponding derived integral cross sections in terms of the partial ionization cross sections corresponding to these cations, in the energy range varying from ionization threshold to 1000 eV, revealed a reasonably good agreement with the experimental and theoretical data, wherever available. In addition to the differential and integral ionization cross sections, we have also calculated the ionization rate coefficients using the evaluated partial ionization cross sections and the Maxwell-Boltzmann distribution as a function of electron energy.

  10. Ionization states of low-energy cosmic rays - Results from Spacelab 3 cosmic-ray experiment

    NASA Technical Reports Server (NTRS)

    Dutta, A.; Goswami, J. N.; Biswas, S.; Durgaprasad, N.; Mitra, B.; Singh, R. K.

    1993-01-01

    The Indian cosmic ray experiment Anuradha, conducted onboard Spacelab 3 during April 29-May 6, 1985 was designed to obtain information on the ionization states of low-energy cosmic rays, using the geomagnetic field as a rigidity filter to place an upper limit on the ionization state of individual cosmic ray particles. This paper presents data confirming the presence of three distinct groups of energetic particles in the near-earth space: (1) low-energy (15-25 MeV/nucleon) anomalous cosmic rays that are either singly ionized or consistent with their being in singly ionized state, (2) fully ionized galactic cosmic ray ions, and (3) partially ionized iron and sub-iron group ions (which account for about 20 percent of all the iron and sub-iron group ions detected at the Spacelab 3 orbit within the magnetosphere in the energy interval 25-125 MeV/nucleon). It is argued that these partially ionized heavy ions are indeed a part of the low-energy galactic cosmic rays present in the interplanetary space.

  11. Spatially resolved thermal desorption/ionization coupled with mass spectrometry

    SciTech Connect

    Jesse, Stephen; Van Berkel, Gary J; Ovchinnikova, Olga S

    2013-02-26

    A system and method for sub-micron analysis of a chemical composition of a specimen are described. The method includes providing a specimen for evaluation and a thermal desorption probe, thermally desorbing an analyte from a target site of said specimen using the thermally active tip to form a gaseous analyte, ionizing the gaseous analyte to form an ionized analyte, and analyzing a chemical composition of the ionized analyte. The thermally desorbing step can include heating said thermally active tip to above 200.degree. C., and positioning the target site and the thermally active tip such that the heating step forms the gaseous analyte. The thermal desorption probe can include a thermally active tip extending from a cantilever body and an apex of the thermally active tip can have a radius of 250 nm or less.

  12. Ionization-based detectors for gas chromatography.

    PubMed

    Poole, Colin F

    2015-11-20

    The gas phase ionization detectors are the most widely used detectors for gas chromatography. The column and makeup gases commonly used in gas chromatography are near perfect insulators. This facilitates the detection of a minute number of charge carriers facilitating the use of ionization mechanisms of low efficiency while providing high sensitivity. The main ionization mechanism discussed in this report are combustion in a hydrogen diffusion flame (flame ionization detector), surface ionization in a plasma (thermionic ionization detector), photon ionization (photoionization detector and pulsed discharge helium ionization detector), attachment of thermal electrons (electron-capture detector), and ionization by collision with metastable helium species (helium ionization detector). The design, response characteristics, response mechanism, and suitability for fast gas chromatography are the main features summarized in this report. Mass spectrometric detection and atomic emission detection, which could be considered as ionization detectors of a more sophisticated and complex design, are not discussed in this report. PMID:25757823

  13. General classification of partially polarized partially coherent beams

    NASA Astrophysics Data System (ADS)

    Martinez-Herrero, Rosario; Piquero, Gemma; Mejias, Pedro M.

    2003-05-01

    The behavior of the so-called generalized degree of polarization of partially coherent partially polarized beams upon free propagation is investigated. On the basis of this parameter a general classification scheme of partially polarized beams is proposed. The results are applied to certain classes of fields of special interest.

  14. Experts' Understanding of Partial Derivatives Using the Partial Derivative Machine

    ERIC Educational Resources Information Center

    Roundy, David; Weber, Eric; Dray, Tevian; Bajracharya, Rabindra R.; Dorko, Allison; Smith, Emily M.; Manogue, Corinne A.

    2015-01-01

    Partial derivatives are used in a variety of different ways within physics. Thermodynamics, in particular, uses partial derivatives in ways that students often find especially confusing. We are at the beginning of a study of the teaching of partial derivatives, with a goal of better aligning the teaching of multivariable calculus with the needs of…

  15. Measuring Ionization at Extreme Densities

    NASA Astrophysics Data System (ADS)

    Kraus, Dominik; Doeppner, Tilo; Kritcher, Andrea; Bachmann, Benjamin; Fletcher, Luke; Falcone, Roger; Gericke, Dirk; Glenzer, Siegfried; Masters, Nathan; Nora, Ryan; Boehm, Kurt; Divol, Laurent; Landen, Otto; Yi, Austin; Kline, John; Redmer, Ronald; Neumayer, Paul

    2015-11-01

    A precise knowledge of ionization at given temperature and density is crucial in order to properly model compressibility and heat capacity of ICF ablator materials for efficient implosions producing energy gain. Here, we present a new experimental platform to perform spectrally resolved x-ray scattering measurements of ionization, density and temperature in imploding CH or beryllium capsules on the National Ignition Facility. Recording scattered x-rays at 9 keV from a zinc He-alpha plasma source at a scattering angle of 120 degrees, first experiments show strong sensitivity to k-shell ionization, while at the same time constraining density and temperature. This platform will allow for x-ray Thomson scattering studies of dense plasmas with free electron densities up to 1025 cm-3, giving the possibility to investigate effects of continuum lowering and Pauli blocking on the ablator ionization state right before stagnation of the implosion.

  16. Double ionization of atomic cadmium

    SciTech Connect

    Linusson, P.; Fritzsche, S.; Eland, J. H. D.; Hedin, L.; Karlsson, L.; Feifel, R.

    2011-02-15

    We have recorded the double photoionization spectrum of atomic Cd at four different photon energies in the range 40-200 eV. The main channel is single ionization and subsequent decay of excited Cd{sup +} states, some involving Coster-Kronig processes, whereas direct double ionization is found to be weak. The decay of the excited Cd{sup +} states shows a strong selectivity, related to the configuration of the final state. Double ionization leading to the Cd{sup 2+} ground state is investigated in some detail and is found to proceed mainly through ionization and decay of 4d correlation satellites. The most prominent autoionization peaks have been identified with the aid of quantum-mechanical calculations.

  17. Salts Are Mostly NOT Ionized.

    ERIC Educational Resources Information Center

    Hawkes, Stephen J.

    1996-01-01

    Discusses the misconception that salts are completely ionizing in solution, the presence of this error in textbooks, probable origins of the error, covalent bonding and ion pairs, and how to tell students the truth. (MKR)

  18. Calculation of multiphoton ionization processes

    NASA Technical Reports Server (NTRS)

    Chang, T. N.; Poe, R. T.

    1976-01-01

    We propose an accurate and efficient procedure in the calculation of multiphoton ionization processes. In addition to the calculational advantage, this procedure also enables us to study the relative contributions of the resonant and nonresonant intermediate states.

  19. Ionization oscillations in Hall accelerators

    NASA Astrophysics Data System (ADS)

    Barral, S.; Peradzyński, Z.

    2010-01-01

    The underlying mechanism of low-frequency oscillations in Hall accelerators is investigated theoretically. It is shown that relaxation oscillations arise from a competition between avalanche ionization and the advective transport of the working gas. The model derived recovers the slow progression and fast recession of the ionization front. Analytical approximations of the shape of current pulses and of the oscillation frequency are provided for the case of large amplitude oscillations.

  20. Resonance ionization for analytical spectroscopy

    DOEpatents

    Hurst, George S.; Payne, Marvin G.; Wagner, Edward B.

    1976-01-01

    This invention relates to a method for the sensitive and selective analysis of an atomic or molecular component of a gas. According to this method, the desired neutral component is ionized by one or more resonance photon absorptions, and the resultant ions are measured in a sensitive counter. Numerous energy pathways are described for accomplishing the ionization including the use of one or two tunable pulsed dye lasers.

  1. The evolution of partially differentiated planetesimals Evidence from iron meteorite groups IAB and IIICD

    NASA Technical Reports Server (NTRS)

    Kracher, A.

    1985-01-01

    Some of the properties of IAB and IIICD iron meteorites thought to be derived from partially differentiated planetesimals are summarized, and the physical aspects that may have controlled parent body differentiation and affected the composition of the sulfide melt are outlined. The chemical evolution of the parent body is then discussed, and observations supporting the partial differentiation model are examined. Finally, an attempt is made to reinterpret barometric and chronometric data in light of the partial differentiation model, and tentative conclusions are presented.

  2. Laser ionization mass spectroscopy

    NASA Astrophysics Data System (ADS)

    Bernardez, Luis J., III; Siekhaus, W. J.

    1989-10-01

    Laser Ionization Mass Spectroscopy (LIMS) is a simple technique with several advantages and disadvantages over standard mass spectroscopy techniques. The LIMS technique uses a laser to vaporize a small portion of a sample. The vapor from the sample consists of a mixture of charged and neutral atoms or fragments. Using electrostatic grids, the ions (positive or negative) are given a known amount of kinetic energy and sent down a time-of-flight tube. The time it takes the ions to travel down the flight tube is recorded. Knowing the ions' energy, the length of the flight tube, and the time it takes the ions to travel that distance, the masses of the ions can be calculated. The instrument used is a LIMA 3 made by Cambridge Mass Spectrometry. It has a Quanta Ray DCR-11 Nd:YAG laser, which was frequency-quadrupled to 266 nm. The laser spot size is typically between 2 and 5 microns in diameter and the pulse width is between 5 and 10 nanoseconds. The energy of the laser is continually variable between 0.1 and 3.0 millijoules. The detector is a 17-stage venetian-blind multiplier made by Thorn EMI. The analysis is carried out under vacuum, usually between 10(exp -8) and 10(exp -9) Torr. The LIMA 3 has several useful features such as: a He-Ne pilot laser used to target the Nd:YAG laser; a microscope (which is used to view the sample through the laser optics); and a precision sample stage for accurate sample alignment.

  3. Laser ionization mass spectroscopy

    SciTech Connect

    Bernardez, L.J. III; Siekhaus, W.J. )

    1989-10-01

    Laser Ionization Mass Spectroscopy (LIMS) is a simple technique with several advantages and disadvantages over standard mass spectroscopy techniques. The LIMS technique uses a laser to vaporize a small portion of a sample. The vapor from the sample consists of a mixture of charged and neutral atoms or fragments. Using electrostatic grids, the ions (positive or negative) are given a known amount of kinetic energy and sent down a time-of-flight tube. The time it takes the ions to travel down the flight tube is recorded. Knowing the ions' energy, the length of the flight tube, and the time it takes the ions to travel that distance, the masses of the ions can be calculated. The instrument we use is a LIMA 3 made by Cambridge Mass Spectrometry. It has a Quanta Ray DCR-11 Nd:YAG laser, which we frequency-quadruple to 266 nm. The laser spot size is typically between 2 and 5 microns in diameter and the pulse width is between 5 and 10 nanoseconds. The energy of the laser is continually variable between 0.1 and 3.0 millijoules. The detector is a 17-stage venetian-blind multiplier made by Thorn EMI. The analysis is carried out under vacuum, usually between 10{sup {minus}8} and 10{sup {minus}9} Torr. The LIMA 3 has several useful features such as: a He-Ne pilot laser used to target the Nd:YAG laser; a microscope (which is used to view the sample through the laser optics); and a precision sample stage for accurate sample alignment. 6 figs., 1 tab.

  4. Body lice

    MedlinePlus

    ... off the body. Your provider may prescribe a skin cream or a wash that contains permethrin, malathione, or benzyl alcohol. If your case is severe, the provider may prescribe medicine that you take by mouth.

  5. Body Image

    MedlinePlus

    ... spider veins Body dysmorphic disorder (BDD) Eating disorders Anorexia nervosa Binge eating disorder Bulimia nervosa Over-exercising ... conditions? Visit our Mental health section. Fact sheets Anorexia nervosa Binge eating disorder Bulimia nervosa Cosmetics and ...

  6. Body Signals.

    ERIC Educational Resources Information Center

    Gurley-Dilger, 'Laine

    1986-01-01

    Describes an activity in which students observe pairs of students engaged in conversation. Observations of "body language" are made, shifts in stance, and duration of stance. Discusses the application of this type of study to other species. (TW)

  7. Body lice

    MedlinePlus

    ... also get lice from infected clothing, towels, or bedding. Body lice are bigger than other types of ... last if you: Bathe regularly Wash clothes and bedding at least once a week Placing clothes in ...

  8. Bog bodies.

    PubMed

    Lynnerup, Niels

    2015-06-01

    In northern Europe during the Iron Age, many corpses were deposited in bogs. The cold, wet and anaerobic environment leads in many cases to the preservation of soft tissues, so that the bodies, when found and excavated several thousand years later, are remarkably intact. Since the 19th century the bog bodies have been studied using medical and natural scientific methods, and recently many bog bodies have been re-examined using especially modern, medical imaging techniques. Because of the preservation of soft tissue, especially the skin, it has been possible to determine lesions and trauma. Conversely, the preservation of bones is less good, as the mineral component has been leached out by the acidic bog. Together with water-logging of collagenous tissue, this means that if the bog body is simply left to dry out when found, as was the case pre-19th century, the bones may literally warp and shrink, leading to potential pitfalls in paleopathological diagnostics. Bog bodies have in several instances been crucial in determining the last meal, as gut contents may be preserved, and thus augment our knowledge on pre-historic diet by adding to, for example, stable isotope analyses. This article presents an overview of our knowledge about the taphomic processes as well as the methods used in bog body research. PMID:25998635

  9. Partially segmented deformable mirror

    DOEpatents

    Bliss, Erlan S.; Smith, James R.; Salmon, J. Thaddeus; Monjes, Julio A.

    1991-01-01

    A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp.

  10. Partially segmented deformable mirror

    DOEpatents

    Bliss, E.S.; Smith, J.R.; Salmon, J.T.; Monjes, J.A.

    1991-05-21

    A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp. 5 figures.

  11. Partial oxidation catalyst

    DOEpatents

    Krumpelt, Michael; Ahmed, Shabbir; Kumar, Romesh; Doshi, Rajiv

    2000-01-01

    A two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion. The dehydrogenation portion is a group VIII metal and the oxide-ion conducting portion is selected from a ceramic oxide crystallizing in the fluorite or perovskite structure. There is also disclosed a method of forming a hydrogen rich gas from a source of hydrocarbon fuel in which the hydrocarbon fuel contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion at a temperature not less than about 400.degree. C. for a time sufficient to generate the hydrogen rich gas while maintaining CO content less than about 5 volume percent. There is also disclosed a method of forming partially oxidized hydrocarbons from ethanes in which ethane gas contacts a two-part catalyst comprising a dehydrogenation portion and an oxide-ion conducting portion for a time and at a temperature sufficient to form an oxide.

  12. Composite electron propagator methods for calculating ionization energies

    NASA Astrophysics Data System (ADS)

    Díaz-Tinoco, Manuel; Dolgounitcheva, O.; Zakrzewski, V. G.; Ortiz, J. V.

    2016-06-01

    Accurate ionization energies of molecules may be determined efficiently with composite electron-propagator (CEP) techniques. These methods estimate the results of a calculation with an advanced correlation method and a large basis set by performing a series of more tractable calculations in which large basis sets are used with simpler approximations and small basis sets are paired with more demanding correlation techniques. The performance of several CEP methods, in which diagonal, second-order electron propagator results with large basis sets are combined with higher-order results obtained with smaller basis sets, has been tested for the ionization energies of closed-shell molecules from the G2 set. Useful compromises of accuracy and computational efficiency employ complete-basis-set extrapolation for second-order results and small basis sets in third-order, partial third-order, renormalized partial-third order, or outer valence Green's function calculations. Analysis of results for vertical as well as adiabatic ionization energies leads to specific recommendations on the best use of regular and composite methods. Results for 22 organic molecules of interest in the design of photovoltaic devices, benzo[a]pyrene, Mg-octaethylporphyrin, and C60 illustrate the capabilities of CEP methods for calculations on large molecules.

  13. Composite electron propagator methods for calculating ionization energies.

    PubMed

    Díaz-Tinoco, Manuel; Dolgounitcheva, O; Zakrzewski, V G; Ortiz, J V

    2016-06-14

    Accurate ionization energies of molecules may be determined efficiently with composite electron-propagator (CEP) techniques. These methods estimate the results of a calculation with an advanced correlation method and a large basis set by performing a series of more tractable calculations in which large basis sets are used with simpler approximations and small basis sets are paired with more demanding correlation techniques. The performance of several CEP methods, in which diagonal, second-order electron propagator results with large basis sets are combined with higher-order results obtained with smaller basis sets, has been tested for the ionization energies of closed-shell molecules from the G2 set. Useful compromises of accuracy and computational efficiency employ complete-basis-set extrapolation for second-order results and small basis sets in third-order, partial third-order, renormalized partial-third order, or outer valence Green's function calculations. Analysis of results for vertical as well as adiabatic ionization energies leads to specific recommendations on the best use of regular and composite methods. Results for 22 organic molecules of interest in the design of photovoltaic devices, benzo[a]pyrene, Mg-octaethylporphyrin, and C60 illustrate the capabilities of CEP methods for calculations on large molecules. PMID:27305999

  14. Thermal ionization of Cs Rydberg states

    NASA Astrophysics Data System (ADS)

    Glukhov, I. L.; Ovsiannikov, V. D.

    2009-01-01

    Rates Pnl of photoionization from Rydberg ns-, np-, nd-states of a valence electron in Cs, induced by black-body radiation, were calculated on the basis of the modified Fues model potential method. The numerical data were approximated with a three-term expression which reproduces in a simple analytical form the dependence of Pnl on the ambient temperature T and on the principal quantum number n. The comparison between approximate and exactly calculated values of the thermal ionization rate demonstrates the applicability of the proposed approximation for highly excited states with n from 20 to 100 in a wide temperature range of T from 100 to 10,000 K. We present coefficients of this approximation for the s-, p- and d-series of Rydberg states.

  15. Yttrium oxide ceramic body

    SciTech Connect

    Greskovich, C.D.; O'Clair, C.R.

    1988-07-05

    This patent describes a process for producing a sintered yttrium oxide body which is at least optically translucent having an in-line spectral transmission greater than 1% taken at a wavelength of 590 nanometers on a thickness of 0.85 millimeter of the sintered body and having an average grain size ranging from about 5 microns to about 50 microns which consists essentially of producing an yttrium oxide powder having an average particle size of less than about 5 microns and being free of particles greater than about 5 microns and having a specific surface area ranging from about 4 square meters per gram to about 25 square meters per gram, forming the powder into a compact having a density of at least about 45% of the density for yttrium oxide, firing the compact at a temperature ranging from about 1625C, to about 1900C, for a time sufficient to produce the sintered body, and reducing the firing temperature at a rate which has no significant deleterious effect on the sintered body. The firing being carried out in an atmosphere of hydrogen, the hydrogen atmosphere containing at least a sufficient partial pressure of oxygen at least after the compact becomes a closed pore body to produce the optically translucent sintered body. The yttrium oxide powder being produced by providing an aqueous yttrium nitrate solution of at least about 0.1 mole of yttrium per liter of solution, providing an aqueous oxalic acid solution having a concentration of at least about 10% excess of that required for complete reaction with the yttrium nitrate, admixing the solutions thereby precipitating yttrium oxalate hydrate, recovering the yttrium oxalate hydrate precipitate.

  16. Gasification and Ionization of Chemically Complex Liquids for FRC Injection

    NASA Astrophysics Data System (ADS)

    Holmes, Michael; Hill, Carrie

    2014-10-01

    Ion thrusters provide reliable and efficient spacecraft propulsion but are limited to noble gas propellants to limit chemical attack of components. However, thrusters based on Field Reversed Configuration (FRC) plasmas are becoming a reality. High beta compact-toroids are generated within an FRC thruster and then expelled to provide thrust. The closed field lines restrict the plasma from attacking thruster components. More convenient propellants such as water are therefore possible. The FRC thruster would generate a series of compact-toroids (plasmoids) to develop continuous spacecraft thrust. Each plasmoid ejection would empty the discharge region. The feed system would then refill the discharge region with partially ionized gas for the next discharge. The ionization part of this feed system is the subject of this paper. The question is how to produce a uniform, chemically complex, ionized gas within the discharge region that optimizes compact-toroid formation? We will be measuring chemical state, ionization state, and uniformity as the propellant enters the discharge region.

  17. Body Imaging

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The high-tech art of digital signal processing (DSP) was pioneered at NASA's Jet Propulsion Laboratory (JPL) in the mid-1960s for use in the Apollo Lunar Landing Program. Designed to computer enhance pictures of the Moon, this technology became the basis for the Landsat Earth resources satellites and subsequently has been incorporated into a broad range of Earthbound medical and diagnostic tools. DSP is employed in advanced body imaging techniques including Computer-Aided Tomography, also known as CT and CATScan, and Magnetic Resonance Imaging (MRI). CT images are collected by irradiating a thin slice of the body with a fan-shaped x-ray beam from a number of directions around the body's perimeter. A tomographic (slice-like) picture is reconstructed from these multiple views by a computer. MRI employs a magnetic field and radio waves, rather than x-rays, to create images. In this photograph, a patient undergoes an open MRI.

  18. Body Imaging

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The high-tech art of digital signal processing (DSP) was pioneered at NASA's Jet Propulsion Laboratory (JPL) in the mid-1960s for use in the Apollo Lunar Landing Program. Designed to computer enhance pictures of the Moon, this technology became the basis for the Landsat Earth resources satellites and subsequently has been incorporated into a broad range of Earthbound medical and diagnostic tools. DSP is employed in advanced body imaging techniques including Computer-Aided Tomography, also known as CT and CATScan, and Magnetic Resonance Imaging (MRI). CT images are collected by irradiating a thin slice of the body with a fan-shaped x-ray beam from a number of directions around the body's perimeter. A tomographic (slice-like) picture is reconstructed from these multiple views by a computer. MRI employs a magnetic field and radio waves, rather than x-rays, to create images.

  19. Prediction of Shock Wave Structure in Weakly Ionized Gas Flow by Solving MGD Equation

    NASA Technical Reports Server (NTRS)

    Deng, Z. T.; Oviedo-Rojas, Ruben; Chow, Alan; Litchford, Ron J.; Cook, Stephen (Technical Monitor)

    2002-01-01

    This paper reports the recent research results of shockwave structure predictions using a new developed code. The modified Rankine-Hugoniot relations across a standing normal shock wave are discussed and adopted to obtain jump conditions. Coupling a electrostatic body force to the Burnett equations, the weakly ionized flow field across the shock wave was solved. Results indicated that the Modified Rankine-Hugoniot equations for shock wave are valid for a wide range of ionization fraction. However, this model breaks down with small free stream Mach number and with large ionization fraction. The jump conditions also depend on the value of free stream pressure, temperature and density. The computed shock wave structure with ionization provides results, which indicated that shock wave strength may be reduced by existence of weakly ionized gas.

  20. Investigation of electric field distribution on FAC-IR-300 ionization chamber

    NASA Astrophysics Data System (ADS)

    Mohammadi, S. M.; Tavakoli-Anbaran, H.; Zeinali, H. Z.

    2016-07-01

    One of the important parameters for establishing charge particle equilibrium (CPE) conditions of free-air ionization chamber is an electric field distribution. In this paper, electric field distribution inside the ionization chamber was investigated by finite element method. For this purpose, the effects of adding guard plate and guard strips on the electric field distribution in the ionization chamber were studied. it is necessary to apply a lead box around the ionization chamber body to avoid of scattered radiation effects on the ionization chamber operation, but the lead box changes the electric field distribution. In the following, the effect of lead box on the electric field distribution was studied. Finally, electric field distribution factor (kfield) was calculated by the simulation. The results of the simulation showed that presence of the guard plate and guard strips, and applying a suitable potential to lead box, a convergence of kfield to 1 was achieved.

  1. Partially supervised speaker clustering.

    PubMed

    Tang, Hao; Chu, Stephen Mingyu; Hasegawa-Johnson, Mark; Huang, Thomas S

    2012-05-01

    Content-based multimedia indexing, retrieval, and processing as well as multimedia databases demand the structuring of the media content (image, audio, video, text, etc.), one significant goal being to associate the identity of the content to the individual segments of the signals. In this paper, we specifically address the problem of speaker clustering, the task of assigning every speech utterance in an audio stream to its speaker. We offer a complete treatment to the idea of partially supervised speaker clustering, which refers to the use of our prior knowledge of speakers in general to assist the unsupervised speaker clustering process. By means of an independent training data set, we encode the prior knowledge at the various stages of the speaker clustering pipeline via 1) learning a speaker-discriminative acoustic feature transformation, 2) learning a universal speaker prior model, and 3) learning a discriminative speaker subspace, or equivalently, a speaker-discriminative distance metric. We study the directional scattering property of the Gaussian mixture model (GMM) mean supervector representation of utterances in the high-dimensional space, and advocate exploiting this property by using the cosine distance metric instead of the euclidean distance metric for speaker clustering in the GMM mean supervector space. We propose to perform discriminant analysis based on the cosine distance metric, which leads to a novel distance metric learning algorithm—linear spherical discriminant analysis (LSDA). We show that the proposed LSDA formulation can be systematically solved within the elegant graph embedding general dimensionality reduction framework. Our speaker clustering experiments on the GALE database clearly indicate that 1) our speaker clustering methods based on the GMM mean supervector representation and vector-based distance metrics outperform traditional speaker clustering methods based on the “bag of acoustic features” representation and statistical

  2. Body Imaging

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Magnetic Resonance Imaging (MRI) and Computer-aided Tomography (CT) images are often complementary. In most cases, MRI is good for viewing soft tissue but not bone, while CT images are good for bone but not always good for soft tissue discrimination. Physicians and engineers in the Department of Radiology at the University of Michigan Hospitals are developing a technique for combining the best features of MRI and CT scans to increase the accuracy of discriminating one type of body tissue from another. One of their research tools is a computer program called HICAP. The program can be used to distinguish between healthy and diseased tissue in body images.

  3. A Combined Desorption Ionization by Charge Exchange (DICE) and Desorption Electrospray Ionization (DESI) Source for Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Chan, Chang-Ching; Bolgar, Mark S.; Miller, Scott A.; Attygalle, Athula B.

    2011-01-01

    A source that couples the desorption ionization by charge exchange (DICE) and desorption electrospray ionization (DESI) techniques together was demonstrated to broaden the range of compounds that can be analyzed in a single mass spectrometric experiment under ambient conditions. A tee union was used to mix the spray reagents into a partially immiscible blend before this mixture was passed through a conventional electrospray (ES) probe capillary. Using this technique, compounds that are ionized more efficiently by the DICE method and those that are ionized better with the DESI procedure could be analyzed simultaneously. For example, hydroquinone, which is not detected when subjected to DESI-MS in the positive-ion generation mode, or the sodium adduct of guaifenesin, which is not detected when examined by DICE-MS, could both be detected in one experiment when the two techniques were combined. The combined technique was able to generate the molecular ion, proton and metal adduct from the same compound. When coupled to a tandem mass spectrometer, the combined source enabled the generation of product ion spectra from the molecular ion and the [M + H]+ or [M + metal]+ ions of the same compound without the need to physically change the source from DICE to DESI. The ability to record CID spectra of both the molecular ion and adduct ions in a single mass spectrometric experiment adds a new dimension to the array of mass spectrometric methods available for structural studies.

  4. A combined desorption ionization by charge exchange (DICE) and desorption electrospray ionization (DESI) source for mass spectrometry.

    PubMed

    Chan, Chang-Ching; Bolgar, Mark S; Miller, Scott A; Attygalle, Athula B

    2011-01-01

    A source that couples the desorption ionization by charge exchange (DICE) and desorption electrospray ionization (DESI) techniques together was demonstrated to broaden the range of compounds that can be analyzed in a single mass spectrometric experiment under ambient conditions. A tee union was used to mix the spray reagents into a partially immiscible blend before this mixture was passed through a conventional electrospray (ES) probe capillary. Using this technique, compounds that are ionized more efficiently by the DICE method and those that are ionized better with the DESI procedure could be analyzed simultaneously. For example, hydroquinone, which is not detected when subjected to DESI-MS in the positive-ion generation mode, or the sodium adduct of guaifenesin, which is not detected when examined by DICE-MS, could both be detected in one experiment when the two techniques were combined. The combined technique was able to generate the molecular ion, proton and metal adduct from the same compound. When coupled to a tandem mass spectrometer, the combined source enabled the generation of product ion spectra from the molecular ion and the [M + H](+) or [M + metal](+) ions of the same compound without the need to physically change the source from DICE to DESI. The ability to record CID spectra of both the molecular ion and adduct ions in a single mass spectrometric experiment adds a new dimension to the array of mass spectrometric methods available for structural studies. PMID:21472555

  5. Partial cross sections of helium satellites at medium photon energies

    SciTech Connect

    Wehlitz, R.; Sellin, I.A.; Hemmers, O.

    1997-04-01

    Still of current interest is the important role of single ionization with excitation compared to single ionization alone. The coupling between the electrons and the incoming photon is a single-particle operator. Thus, an excitation in addition to an ionization, leading to a so-called satellite line in a photoelectron spectrum, is entirely due to electron-electron interaction and probes the electron correlation in the ground and final state. Therefore the authors have undertaken the study of the intensity of helium satellites He{sup +}nl (n = 2 - 6) relative to the main photoline (n = 1) as a function of photon energy at photon energies well above threshold up to 900 eV. From these results they could calculate the partial cross-sections of the helium satellites. In order to test the consistency of their satellite-to-1s ratios with published double-to-single photoionization ratios, the authors calculated the double-to-single photoionization ratio from their measured ratios using the theoretical energy-distribution curves of Chang and Poe and Le Rouzo and Dal Cappello which proved to be valid for photon energies below 120 eV. These calculated double-to-single ionization ratios agree fairly well with recent ion measurements. In the lower photon energy range the authors ratios agree better with the ratios of Doerner et al. while for higher photon energies the agreement is better with the values of Levin et al.

  6. Plasma Bragg density gratings produced by optical-field ionization

    SciTech Connect

    Yu Lule; Sheng Zhengming; Zhang Jie

    2009-11-15

    Plasma Bragg density gratings produced by optical-field ionization in underdense gas under the irradiation of two counterpropagating laser pulses at laser intensities around 10{sup 13} W/cm{sup 2} are investigated by particle-in-cell simulation. The grating is composed of interlacing layers of neutral gas and plasma (or partially ionized gas) with its density and period controlled by the initial gas density, laser wavelengths, and intersecting angles of the two laser pulses. The study shows that such gratings have a longer lifetime, about nanoseconds, as compared with those driven by the laser ponderomotive force at higher laser intensities around 10{sup 15} W/cm{sup 2}. They may be used for phase-matched high-harmonic generation, laser self-guiding, laser pulse compression and stretching, etc.

  7. UNEXPECTED IONIZATION STRUCTURE IN ETA CARINAE'S ''WEIGELT KNOTS''

    SciTech Connect

    Remmen, Grant N.; Davidson, Kris; Mehner, Andrea

    2013-08-10

    The Weigelt knots, dense slow-moving ejecta near {eta} Carinae, are mysterious in structure as well as in origin. Using spatially dithered spectrograms obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS), we have partially resolved the ionization zones of one knot. Contrary to simple models, higher ionization levels occur on the outer side, i.e., farther from the star. They cannot represent a bow shock, and no satisfying explanation is yet available-though we sketch one qualitative possibility. STIS spectrograms provide far more reliable spatial measurements of the Weigelt knots than HST images do, and this technique can also be applied to the knots' proper motion problem. Our spatial measurement accuracy is about 10 mas, corresponding to a projected linear scale of the order of 30 AU, which is appreciably smaller than the size of each Weigelt knot.

  8. Partial hepatectomy in mice.

    PubMed

    Nevzorova, Y A; Tolba, R; Trautwein, C; Liedtke, C

    2015-04-01

    The surgical procedure of two-thirds partial hepatectomy (PH) in rodents was first described more than 80 years ago by Higgins and Anderson. Nevertheless, this technique is still a state-of-the-art method for the community of liver researchers as it allows the in-depth analysis of signalling pathways involved in liver regeneration and hepatocarcinogenesis. The importance of PH as a key method in experimental hepatology has even increased in the last decade due to the increasing availability of genetically-modified mouse strains. Here, we propose a standard operating procedure (SOP) for the implementation of PH in mice, which is based on our experience of more than 10 years. In particular, the SOP offers all relevant background information on the PH model and provides comprehensive guidelines for planning and performing PH experiments. We provide established recommendations regarding optimal age and gender of animals, use of appropriate anaesthesia and biometric calculation of the experiments. We finally present an easy-to-follow step-by-step description of the complete surgical procedure including required materials, critical steps and postoperative management. This SOP especially takes into account the latest changes in animal welfare rules in the European Union but is still in agreement with current international regulations. In summary, this article provides comprehensive information for the legal application, design and implementation of PH experiments. PMID:25835741

  9. Partial covariate adjusted regression

    PubMed Central

    Şentürk, Damla; Nguyen, Danh V.

    2008-01-01

    Covariate adjusted regression (CAR) is a recently proposed adjustment method for regression analysis where both the response and predictors are not directly observed (Şentürk and Müller, 2005). The available data has been distorted by unknown functions of an observable confounding covariate. CAR provides consistent estimators for the coefficients of the regression between the variables of interest, adjusted for the confounder. We develop a broader class of partial covariate adjusted regression (PCAR) models to accommodate both distorted and undistorted (adjusted/unadjusted) predictors. The PCAR model allows for unadjusted predictors, such as age, gender and demographic variables, which are common in the analysis of biomedical and epidemiological data. The available estimation and inference procedures for CAR are shown to be invalid for the proposed PCAR model. We propose new estimators and develop new inference tools for the more general PCAR setting. In particular, we establish the asymptotic normality of the proposed estimators and propose consistent estimators of their asymptotic variances. Finite sample properties of the proposed estimators are investigated using simulation studies and the method is also illustrated with a Pima Indians diabetes data set. PMID:20126296

  10. Body Levers.

    ERIC Educational Resources Information Center

    Chiappetta, Eugene L.

    1987-01-01

    Explains how the muscle and bone arrangement of the human body can be used in teaching the principles of simple machines. Presents an activity that investigates the lever system of the forearm. Includes background information on levers and suggests questions for classroom discussion. (ML)

  11. Microwave ionization of Rydberg atoms

    SciTech Connect

    Gallagher, T.F.

    1996-12-31

    An atom can be ionized by a static field if the field depresses the potential below the binding energy W, leading to the requirement E = W{sup 2}/4 in atomic units. The atomic units of field and energy are 5.14 {times} 10{sup 9} V/cm and 27.2 eV. The ionization field is often expressed in terms of the principal quantum number n of the state in question as E = 1/16n{sup 4}. In a microwave field with frequency far less than the separation {Delta}W = 1/n{sup 3} between adjacent n states, atoms other than H ionize at the much lower microwave field amplitude of E = 1/3n{sup 5}. This field corresponds to the Inglis-Teller limit, where it is impossible to resolve spectrally adjacent n states due to Stark broadening in a plasma. In H ionization occurs as it does in a static field. The difference exists because the finite sized ionic core of a non hydrogenic atom breaks one of the symmetries found in H. In non hydrogenic atoms the microwave field drives a series of transitions through successively higher n states culminating in ionization. These transitions can be understood in terms of a Landau-Zener picture based on the variation of the energies of the atoms produced by the time varying field or as the resonant multiphoton absorption of the microwave photons. In either case, the atoms make transitions through real intermediate states en route to ionization. With short, four cycle, microwave pulses complete ionization does not occur with fields of E = 1/3n{sup 5}, and population is left in intermediate states. The transition from ionization at fields near E = 1/3n{sup 5} to fields of E = 1/16n{sup 4} occurs when the frequency becomes low enough that the energies of the states vary adiabatically in the temporally varying field.

  12. Partial lipodystrophy in coeliac disease.

    PubMed Central

    O'Mahony, D; O'Mahony, S; Whelton, M J; McKiernan, J

    1990-01-01

    The association of coeliac disease and partial lipodystrophy is described. The patient also had deficiencies of serum IgA and C3 complement (the latter associated with partial lipodystrophy). In addition, there was subclinical dermatitis herpetiformis confirmed by skin biopsy. The facial wasting of fully developed partial lipodystrophy may be misinterpreted as a sign of malabsorption but the facial, upper limb, and truncal lipodystrophy contrasts with normal pelvic and lower limb appearances. Images Figure 1 Figure 2 PMID:2379878

  13. Characteristics of low-temperature plasma ionization for ambient mass spectrometry compared to electrospray ionization and atmospheric pressure chemical ionization.

    PubMed

    Albert, Anastasia; Engelhard, Carsten

    2012-12-18

    Ambient desorption/ionization mass spectrometry (ADI-MS) is an attractive method for direct analysis with applications in homeland security, forensics, and human health. For example, low-temperature plasma probe (LTP) ionization was successfully used to detect, e.g., explosives, drugs, and pesticides directly on the target. Despite the fact that the field is gaining significant attention, few attempts have been made to classify ambient ionization techniques based on their ionization characteristics and performance compared to conventional ionization sources used in mass spectrometry. In the present study, relative ionization efficiencies (RIEs) for a large group of compound families were determined with LTP-Orbitrap-MS and compared to those obtained with electrospray ionization mass spectrometry (ESI-MS) and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). RIEs were normalized against one reference compound used across all methods to ensure comparability of the results. Typically, LTP analyte ionization through protonation/deprotonation (e.g., 4-acetamidophenol) was observed; in some cases (e.g., acenaphthene) radicals were formed. Amines, amides, and aldehydes were ionized successfully with LTP. A benefit of LTP over conventional methods is the possibility to successfully ionize PAHs and imides. Here, the studied model compounds could be detected by neither APCI nor ESI. LTP is a relatively soft ionization method because little fragmentation of model compounds was observed. It is considered to be an attractive method for the ionization of low molecular weight compounds over a relatively wide polarity range. PMID:23134531

  14. Trigonometric Integrals via Partial Fractions

    ERIC Educational Resources Information Center

    Chen, H.; Fulford, M.

    2005-01-01

    Parametric differentiation is used to derive the partial fractions decompositions of certain rational functions. Those decompositions enable us to integrate some new combinations of trigonometric functions.

  15. Low partial discharge vacuum feedthrough

    NASA Technical Reports Server (NTRS)

    Benham, J. W.; Peck, S. R.

    1979-01-01

    Relatively discharge free vacuum feedthrough uses silver-plated copper conductor jacketed by carbon filled silicon semiconductor to reduce concentrated electric fields and minimize occurrence of partial discharge.

  16. In Defense of Body CT

    PubMed Central

    McCollough, Cynthia H.; Guimarães, Luís; Fletcher, Joel G.

    2009-01-01

    Rapid technical developments, and an expanding list of applications that have supplanted less accurate or more invasive diagnostic tests, have led to a dramatic increase in the use of body CT imaging in medical practice since its introduction in 1975. Our purpose here is to discuss medical justification of the small risk associated with the ionizing radiation used in CT and to provide perspectives on practice-specific decisions that can maximize overall patient benefit. In addition, we review available dose management and optimization technique. PMID:19542392

  17. Experts' understanding of partial derivatives using the partial derivative machine

    NASA Astrophysics Data System (ADS)

    Roundy, David; Weber, Eric; Dray, Tevian; Bajracharya, Rabindra R.; Dorko, Allison; Smith, Emily M.; Manogue, Corinne A.

    2015-12-01

    [This paper is part of the Focused Collection on Upper Division Physics Courses.] Partial derivatives are used in a variety of different ways within physics. Thermodynamics, in particular, uses partial derivatives in ways that students often find especially confusing. We are at the beginning of a study of the teaching of partial derivatives, with a goal of better aligning the teaching of multivariable calculus with the needs of students in STEM disciplines. In this paper, we report on an initial study of expert understanding of partial derivatives across three disciplines: physics, engineering, and mathematics. We report on the central research question of how disciplinary experts understand partial derivatives, and how their concept images of partial derivatives differ, with a focus on experimentally measured quantities. Using the partial derivative machine (PDM), we probed expert understanding of partial derivatives in an experimental context without a known functional form. In particular, we investigated which representations were cued by the experts' interactions with the PDM. Whereas the physicists and engineers were quick to use measurements to find a numeric approximation for a derivative, the mathematicians repeatedly returned to speculation as to the functional form; although they were comfortable drawing qualitative conclusions about the system from measurements, they were reluctant to approximate the derivative through measurement. On a theoretical front, we found ways in which existing frameworks for the concept of derivative could be expanded to include numerical approximation.

  18. Low-Pressure, Field-Ionizing Mass Spectrometer

    NASA Technical Reports Server (NTRS)

    Hartley, Frank; Smith, Steven

    2009-01-01

    A small mass spectrometer utilizing a miniature field ionization source is now undergoing development. It is designed for use in a variety of applications in which there are requirements for a lightweight, low-power-consumption instrument that can analyze the masses of a wide variety of molecules and ions. The device can operate without need for a high-vacuum, carrier-gas feed radioactive ionizing source, or thermal ionizer. This mass spectrometer can operate either in the natural vacuum of outer space or on Earth at any ambient pressure below 50 torr (below about 6.7 kPa) - a partial vacuum that can easily be reached by use of a small sampling pump. This mass spectrometer also has a large dynamic range - from singly charged small gas ions to deoxyribonucleic acid (DNA) fragments larger than 104 atomic mass units - with sensitivity adequate for detecting some molecules and ions at relative abundances of less than one part per billion. This instrument (see figure) includes a field ionizer integrated with a rotating-field mass spectrometer (RFMS). The field ionizer effects ionization of a type characterized as "soft" in the art because it does not fragment molecules or initiate avalanche arcing. What makes the "soft" ionization mode possible is that the distance between the ionizing electrodes is less than mean free path for ions at the maximum anticipated operating pressure, so that the ionizer always operates on the non-breakdown side of the applicable Paschen curve (a standard plot of breakdown potential on the ordinate and pressure electrode separation on the abscissa). The field ionizer in this instrument is fabricated by micromachining a submicron-thick membrane out of an electrically nonconductive substrate, coating the membrane on both sides to form electrodes, then micromachining small holes through the electrodes and membrane. Because of the submicron electrode separation, even a potential of only 1 V applied between the electrodes gives rise to an electric

  19. Ionization yield and isotopic selectivity of three-step photoionization of atoms by pulsed lasers

    NASA Astrophysics Data System (ADS)

    Gupta, G. P.; Suri, B. M.

    2002-06-01

    Estimate of ionization yield and selectivity in multi-step photoionization is of interest in studies related to trace analysis and laser isotope separation. Analytical expressions of ionization yield for the desired and interfering isotopes have been derived by solving rate equations for three-step photoionization. The partial overlap of absorption lines of the isotopes and the charge exchange of the ions of the desired isotope with the atoms of the interfering isotope have been considered. The ionization yield and the isotopic selectivity of the photoionization process are calculated for ytterbium isotopes, considering various atomic and laser parameters. Numerical results have been discussed, showing the effect of both factors on the ionization yield and the isotopic selectivity of the process.

  20. Integral-equation approach to the weak-field asymptotic theory of tunneling ionization

    NASA Astrophysics Data System (ADS)

    Dnestryan, Andrey I.; Tolstikhin, Oleg I.

    2016-03-01

    An integral equation approach to the weak-field asymptotic theory (WFAT) of tunneling ionization is developed. An integral representation for the exact partial amplitudes of ionization into parabolic channels is derived. The WFAT expansion for the ionization rate follows immediately from this relation. Integral representations for the coefficients in the expansion are obtained. The integrals accumulate where the ionizing orbital has large amplitude and are not sensitive to its behavior in the asymptotic region. Hence, these formulas enable one to reliably calculate the WFAT coefficients even if the orbital is represented by an expansion in Gaussian basis, as is usually the case in standard software packages for electronic structure calculations. This development is expected to greatly simplify the implementation of the WFAT for polyatomic molecules, and thus facilitate its growing applications in strong-field physics.

  1. [Body contouring].

    PubMed

    Krüger, N; Lübberding, S; Sattler, G

    2015-10-01

    In our contemporary postmodern society, a modified perception of the human body is accompanied by an increasing demand for body shaping procedures. The treatment needs to be effective but it is just as important that they are safe and can be easily integrated into the daily working and routine schedule. While the options for minimally invasive volume addition are largely limited to injectable implants based on hyaluronic acid or autologous fat, a multitude of options are available for volume reduction. Before deciding on the method of choice, the following needs to be considered: which indications need to be treated, the extent of the reduction in volume and how much pain and possible undesired reactions the patient is prepared to accept. PMID:26349684

  2. Numerical studies of ablation and ionization of railgun materials

    SciTech Connect

    Schnurr, N.M.; Kerrisk, J.F.

    1985-01-01

    The intense radiation from the arc in a railgun may cause vaporization and partial ionization of rail and insulator material. The mass of material added to the arc can have a significant adverse effect on projectile velocity. A numerical model has been developed to predict the change in mass of the arc as a function of several parameters. That model has been incorporated in the Los Alamos Railgun Estimator (LARGE) code and simulations have been run to assess the accuracy of the model. Analytical predictions were found to be in good agreement with experimental data for railgun tests run at Los Alamos. Ablation appears to have a significant effect on railgun performance.

  3. Multifluid magnetohydrodynamics of weakly ionized plasmas

    NASA Astrophysics Data System (ADS)

    Menzel, Raymond

    The process of star formation is an integral part of the new field of astrobiology, which studies the origins of life. Since the gas that collapses to form stars and their resulting protoplanetary disks is known to be weakly ionized and contain magnetic fields, star formation is governed by multifluid magnetohydrodynamics. In this thesis we consider two important problems involved in the process of star formation that may have strongly affected the origins of life, with the goal of determining the thermal effects of these flows and modeling the physical conditions of these environments. We first considered the outstanding problem of how primitive bodies, specifically asteroids, were heated in protoplanetary disks early in their lifetime. Reexamining asteroid heating due to the classic unipolar induction heating mechanism described by Sonett et al. (1970), we find that this mechanism contains a subtle conceptual error. As original conceived, heating due to this mechanism is driven by a uniform, supersonic, fully-ionized, magnetized, T Tauri solar wind, which sweeps past an asteroid and causes the asteroid to experience a motional electric field in its rest frame. We point out that this mechanism ignores the interaction between the body surface and the flow, and thus only correctly describes the electric field far away from the asteroid where the plasma streams freely. In a realistic protoplanetary disk environment, we show that the interaction due to friction between the asteroid surface and the flow causes a shear layer to form close to the body, wherein the motional electric field predicted by Sonett et al. decreases and tends to zero at the asteroid surface. We correct this error by using the equations of multifluid magnetohydrodynamics to explicitly treat the shear layer. We calculate the velocity field in the plasma, and the magnetic and electric fields everywhere for two flows over an idealized infinite asteroid with varying magnetic field orientations. We

  4. Similarity of ionized gas nebulae around unobscured and obscured quasars

    NASA Astrophysics Data System (ADS)

    Liu, Guilin; Zakamska, Nadia L.; Greene, Jenny E.

    2014-08-01

    Quasar feedback is suspected to play a key role in the evolution of massive galaxies, by removing or reheating gas in quasar host galaxies and thus limiting the amount of star formation. In this paper, we continue our investigation of quasar-driven winds on galaxy-wide scales. We conduct Gemini Integral Field Unit spectroscopy of a sample of luminous unobscured (type 1) quasars, to determine the morphology and kinematics of ionized gas around these objects, predominantly via observations of the [O III] λ5007 Å emission line. We find that ionized gas nebulae extend out to ˜13 kpc from the quasar, that they are smooth and round, and that their kinematics are inconsistent with gas in dynamical equilibrium with the host galaxy. The observed morphological and kinematic properties are strikingly similar to those of ionized gas around obscured (type 2) quasars with matched [O III] luminosity, with marginal evidence that nebulae around unobscured quasars are slightly more compact. Therefore, in samples of obscured and unobscured quasars carefully matched in [O III] luminosity, we find support for the standard geometry-based unification model of active galactic nuclei, in that the intrinsic properties of the quasars, of their hosts and of their ionized gas appear to be very similar. Given the apparent ubiquity of extended ionized regions, we are forced to conclude that either the quasar is at least partially illuminating pre-existing gas or that both samples of quasars are seen during advanced stages of quasar feedback. In the latter case, we may be biased by our [O III]-based selection against quasars in the early `blow-out' phase, for example due to dust obscuration.

  5. Ionization and pulse lethargy effects in inverse Cherenkov accelerators

    SciTech Connect

    Sprangle, P.; Hubbard, R.F.,; Hafizi, B.,

    1997-05-01

    Ionization processes limit the accelerating gradient and place an upper limit on the pulse duration of the electromagnetic driver in the inverse Cherenkov accelerator (ICA). Group velocity slippage, i.e., pulse lethargy, on the other hand, imposes a lower limit on the pulse duration. These limits are obtained for two ICA configurations in which the electromagnetic driver (e.g., laser or millimeter wave source) is propagated in a waveguide that is (i) lined with a dielectric material or (ii) filled with a neutral gas. In either configuration the electromagnetic driving field is guided and has an axial electric field with phase velocity equal to the speed of light in vacuum, c. The intensity of the driver in the ICA, and therefore the acceleration gradient, is limited by tunneling and collisional ionization effects. Partial ionization of the dielectric liner or gas can lead to significant modification of the dispersive properties of the waveguide, altering the phase velocity of the accelerating field and causing particle slippage, thus disrupting the acceleration process. An additional limitation on the pulse duration is imposed since the group velocity of the driving pulse is less than c and the pulse slips behind the accelerated electrons. Hence for sufficiently short pulses the electrons outrun the pulse, terminating the acceleration. Limitations on the driver pulse duration and accelerating gradient, due to ionization and pulse lethargy, are estimated for the two ICA configurations. Maximum accelerating gradients and pulse durations are presented for a 10 {mu}m, 1 mm, and 1 cm wavelength electromagnetic driver. The combination of ionization and pulse lethargy effects impose severe limitations on the maximum energy gain in inverse Cherenkov accelerators. {copyright} {ital 1997} {ital The American Physical Society}

  6. Autosomal Trisomies and Partial Trisomy Syndromes

    PubMed Central

    Zaleski, W. A.

    1963-01-01

    The establishing of 46 chromosomes as the normal complement in man and the report of the sex chromatin bodies in buccal smears were followed by reports of trisomies and other abnormal patterns of the X and Y chromosomes in Klinefelter's and Turner's syndromes. Abnormal autosomal complements were described in mongolism, in the E-trisomy syndrome, the D-trisomy syndrome, in the Sturge-Weber syndrome, Waldenstrom's macroglobulinemia, benign congenital hypotonia, atrial septal defect and in the schizoid personality. Certain of these conditions, as well as the “oral-facial-digital” syndrome, were also found to exist as partial trisomies. The mechanism of a trisomy is one of non-disjunction and of partial trisomy translocation or insertion. Two cases of the partial trisomy in the E group are described; these are of especial interest because of the familial incidence, longer survival and male sex occurrence, features which are rarely seen in the full E-trisomy syndrome. ImagesFig. 4Fig. 5Fig. 6 PMID:20327419

  7. The body fades away: investigating the effects of transparency of an embodied virtual body on pain threshold and body ownership

    PubMed Central

    Martini, Matteo; Kilteni, Konstantina; Maselli, Antonella; Sanchez-Vives, Maria V.

    2015-01-01

    The feeling of “ownership” over an external dummy/virtual body (or body part) has been proven to have both physiological and behavioural consequences. For instance, the vision of an “embodied” dummy or virtual body can modulate pain perception. However, the impact of partial or total invisibility of the body on physiology and behaviour has been hardly explored since it presents obvious difficulties in the real world. In this study we explored how body transparency affects both body ownership and pain threshold. By means of virtual reality, we presented healthy participants with a virtual co-located body with four different levels of transparency, while participants were tested for pain threshold by increasing ramps of heat stimulation. We found that the strength of the body ownership illusion decreases when the body gets more transparent. Nevertheless, in the conditions where the body was semi-transparent, higher levels of ownership over a see-through body resulted in an increased pain sensitivity. Virtual body ownership can be used for the development of pain management interventions. However, we demonstrate that providing invisibility of the body does not increase pain threshold. Therefore, body transparency is not a good strategy to decrease pain in clinical contexts, yet this remains to be tested. PMID:26415748

  8. The body fades away: investigating the effects of transparency of an embodied virtual body on pain threshold and body ownership.

    PubMed

    Martini, Matteo; Kilteni, Konstantina; Maselli, Antonella; Sanchez-Vives, Maria V

    2015-01-01

    The feeling of "ownership" over an external dummy/virtual body (or body part) has been proven to have both physiological and behavioural consequences. For instance, the vision of an "embodied" dummy or virtual body can modulate pain perception. However, the impact of partial or total invisibility of the body on physiology and behaviour has been hardly explored since it presents obvious difficulties in the real world. In this study we explored how body transparency affects both body ownership and pain threshold. By means of virtual reality, we presented healthy participants with a virtual co-located body with four different levels of transparency, while participants were tested for pain threshold by increasing ramps of heat stimulation. We found that the strength of the body ownership illusion decreases when the body gets more transparent. Nevertheless, in the conditions where the body was semi-transparent, higher levels of ownership over a see-through body resulted in an increased pain sensitivity. Virtual body ownership can be used for the development of pain management interventions. However, we demonstrate that providing invisibility of the body does not increase pain threshold. Therefore, body transparency is not a good strategy to decrease pain in clinical contexts, yet this remains to be tested. PMID:26415748

  9. Chemical protection against ionizing radiation

    NASA Astrophysics Data System (ADS)

    Maisin, J. R.

    Some of the problems related to chemical protection against ionizing radiation are discussed with emphasis on : definition, classification, degree of protection, mechanisms of action and toxicity. Results on the biological response modifyers (BRMs) and on the combination of nontoxic (i.e. low) doses of sulphydryl radioprotectors and BRMs are presented.

  10. Ionization Potentials for Isoelectronic Series.

    ERIC Educational Resources Information Center

    Agmon, Noam

    1988-01-01

    Presents a quantitative treatment of ionization potentials of isoelectronic atoms. By looking at the single-electron view of calculating the total energy of an atom, trends in the screening and effective quantum number parameters are examined. Approaches the question of determining electron affinities. (CW)

  11. On the interweaving of partial cross sections of different parity

    NASA Technical Reports Server (NTRS)

    Devries, P. L.; George, T. F.

    1979-01-01

    Partial cross sections of definite parity, calculated for electronic-rotational energy transfer in the F +H2 collision system, interweave with increasing total angular momentum J. An explanation, in terms of diabatic curve crossings induced by the centrifugal potential in the body-fixed coordinate system, predicts the interweaving to occur only in systems having half-integer J.

  12. Are Electron Partial Waves Real

    NASA Astrophysics Data System (ADS)

    Yenen, O.; McLaughlin, K. W.

    2005-05-01

    Experiments determining the partial wave content of electrons are uncommon. The standard approach to partial wave expansion of the wavefunction of electrons often ignores their spin. In this non-relativistic approximation the partial waves are labeled by their orbital angular momentum quantum number, e.g. d-waves. As our previous work has shown, this non-relativistic approximation usually fails for photoelectrons. Partial waves should be further specified by their total angular momentum. With d-waves for example, one would need to distinguish between d3/2 and d5/2 partial waves. Although energetically degenerate, fully relativistic d3/2 and d5/2 partial waves of photoelectrons have fundamentally different angular distributions. Using experimental and theoretical methods we have developed, we obtain partial wave probabilities of photoelectrons from polarization measurements of ionic fluorescence. We found that for selected states of the residual ion, there are energy regions where the photoelectron is in a single partial wave with predictable angular distributions.

  13. Biostereometric analysis of body form

    NASA Technical Reports Server (NTRS)

    Whittle, M. W.; Herron, R. L.; Cuzzi, J. R.

    1977-01-01

    Four-camera stereophotogrammetry of Skylab crewmen, preflight and postflight, revealed a loss of volume of one to one and one-half liters from the legs, much of which was replaced during the first 4 postflight days. It is estimated that about one third of the loss represents partial atrophy due to relative disuse in zero-gravity, the remainder being due to a deficit in body fluid. Reduction in volume of the abdomen has also been noted.

  14. A new fifth parameter for transverse isotropy II: partial derivatives

    NASA Astrophysics Data System (ADS)

    Kawakatsu, Hitoshi

    2016-07-01

    Kawakatsu et al. and Kawakatsu introduced a new fifth parameter, ηκ, to describe transverse isotropy (TI). Considering that ηκ characterizes the incidence angle dependence of body wave phase velocities for TI models, its relevance for body wave seismology is obvious. Here, we derive expressions for partial derivatives (sensitivity kernels) of surface wave phase velocity and normal mode eigenfrequency for the new set of five parameters. The partial derivative for ηκ is about twice as large as that for the conventional η, indicating that ηκ should be more readily resolved. While partial derivatives for S velocities are not so changed, those for P velocities are significantly modified; the sensitivity for anisotropic P velocities is greatly reduced. In contrary to the suggestion by Dziewonski & Anderson and Anderson & Dziewonski, there is not much control on the anisotropic P velocities. On the other hand, the significance of ηκ for long-period seismology has become clear.

  15. Intense laser ionization of transiently aligned CO

    SciTech Connect

    Pinkham, D.; Jones, R.R.

    2005-08-15

    We have measured the ionization rate for CO molecules exposed to intense 30 fsec 780 nm laser pulses as a function of the angle between the molecular and laser polarization axes. Nonionizing, 70 fsec laser pulses are used to coherently prepare the molecules, preferentially aligning them for the strong-field ionization experiments. We find a 2:1 ionization-rate ratio for molecules aligned parallel or perpendicular to the ionizing field.

  16. Five-photon double ionization of helium

    NASA Astrophysics Data System (ADS)

    Li, Y.; Pindzola, M. S.; Colgan, J.

    2016-03-01

    A time-dependent close-coupling method is used to calculate the five-photon double ionization of He. It is found that the generalized cross section used in the past for two-photon double ionization of He cannot be extended to five-photon double ionization of He. Therefore only five-photon double ionization probabilities that depend on specific radiation field pulses can be calculated.

  17. Electron-impact ionization of the K-shells of Heavy Atoms

    NASA Astrophysics Data System (ADS)

    Pindzola, M. S.

    2016-05-01

    Fully-relativistic subconfiguration-average distorted-wave (SCADW) calculations are made for the electron-impact ionization of the K-shells of heavy atoms. One set of calculations only include the two-body electrostatic interaction, while the other set includes the full two-body retarded electromagnetic interaction. The SCADW retarded electromagnetic calculations are found to be in good agreement with recent measurements made at the Institute for Physics at the University of Sao Paulo, Brazil for Au and Bi atoms. Calculations and measurements will also be presented for the K-shell ionization of the Ta atom. Work supported in part by Grants from NSF and DOE.

  18. Planarian Immobilization, Partial Irradiation, and Tissue Transplantation

    PubMed Central

    Guedelhoefer IV, Otto C.; Sánchez Alvarado, Alejandro

    2012-01-01

    The planarian, a freshwater flatworm, has proven to be a powerful system for dissecting metazoan regeneration and stem cell biology1,2. Planarian regeneration of any missing or damaged tissues is made possible by adult stem cells termed neoblasts3. Although these stem cells have been definitively shown to be pluripotent and singularly capable of reconstituting an entire animal4, the heterogeneity within the stem cell population and the dynamics of their cellular behaviors remain largely unresolved. Due to the large number and wide distribution of stem cells throughout the planarian body plan, advanced methods for manipulating subpopulations of stem cells for molecular and functional study in vivo are needed. Tissue transplantation and partial irradiation are two methods by which a subpopulation of planarian stem cells can be isolated for further study. Each technique has distinct advantages. Tissue transplantation allows for the introduction of stem cells, into a naïve host, that are either inherently genetically distinct or have been previously treated pharmacologically. Alternatively, partial irradiation allows for the isolation of stem cells within a host, juxtaposed to tissue devoid of stem cells, without the introduction of a wound or any breech in tissue integrity. Using these two methods, one can investigate the cell autonomous and non-autonomous factors that control stem cell functions, such as proliferation, differentiation, and migration. Both tissue transplantation5,6 and partial irradiation7 have been used historically in defining many of the questions about planarian regeneration that remain under study today. However, these techniques have remained underused due to the laborious and inconsistent nature of previous methods. The protocols presented here represent a large step forward in decreasing the time and effort necessary to reproducibly generate large numbers of grafted or partially irradiated animals with efficacies approaching 100 percent. We

  19. Absolute total and partial dissociative cross sections of pyrimidine at electron and proton intermediate impact velocities

    SciTech Connect

    Wolff, Wania Luna, Hugo; Sigaud, Lucas; Montenegro, Eduardo C.; Tavares, Andre C.

    2014-02-14

    Absolute total non-dissociative and partial dissociative cross sections of pyrimidine were measured for electron impact energies ranging from 70 to 400 eV and for proton impact energies from 125 up to 2500 keV. MOs ionization induced by coulomb interaction were studied by measuring both ionization and partial dissociative cross sections through time of flight mass spectrometry and by obtaining the branching ratios for fragment formation via a model calculation based on the Born approximation. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation proved to be a useful tool to determine the vacancy population of the valence MOs from which several sets of fragment ions are produced. It was also a key point to distinguish the dissociation regimes induced by both particles. A comparison with previous experimental results is also presented.

  20. Electron-Impact Ionization and Dissociative Ionization of Biomolecules

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Chaban, Galina M.; Dateo, Christopher E.

    2006-01-01

    It is well recognized that secondary electrons play an important role in radiation damage to humans. Particularly important is the damage of DNA by electrons, potentially leading to mutagenesis. Molecular-level study of electron interaction with DNA provides information on the damage pathways and dominant mechanisms. Our study of electron-impact ionization of DNA fragments uses the improved binary-encounter dipole model and covers DNA bases, sugar phosphate backbone, and nucleotides. An additivity principle is observed. For example, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C3(sup prime)- and C5 (sup prime)-deoxyribose-phospate cross sections, differing by less than 5%. Investigation of tandem double lesion initiated by electron-impact dissociative ionization of guanine, followed by proton reaction with the cytosine in the Watson-Crick pair, is currently being studied to see if tandem double lesion can be initiated by electron impact. Up to now only OH-induced tandem double lesion has been studied.

  1. High Productivity Implantation ''PARTIAL IMPLANT''

    SciTech Connect

    Hino, Masayoshi; Miyamoto, Naoki; Sakai, Shigeki; Matsumoto, Takao

    2008-11-03

    The patterned ion implantation 'PARTIAL IMPLANT' has been developed as a productivity improvement tool. The Partial Implant can form several different ion dose areas on the wafer surface by controlling the speed of wafer moving and the stepwise rotation of twist axis. The Partial Implant system contains two implant methods. One method is 'DIVIDE PARTIAL IMPLANT', that is aimed at reducing the consumption of the wafer. The Divide Partial Implant evenly divides dose area on one wafer surface into two or three different dose part. Any dose can be selected in each area. So the consumption of the wafer for experimental implantation can be reduced. The second method is 'RING PARTIAL IMPLANT' that is aimed at improving yield by correcting electrical characteristic of devices. The Ring Partial Implant can form concentric ion dose areas. The dose of wafer external area can be selected to be within plus or minus 30% of dose of wafer central area. So the electrical characteristic of devices can be corrected by controlling dose at edge side on the wafer.

  2. Computer copings for partial coverage.

    PubMed

    Denissen, H; van der Zel, J; Reisig, J; Vlaar, S; de Ruiter, W; van Waas, R

    1999-04-01

    Partial coverage posterior tooth preparations are very complex surfaces for computer surface digitization, computer design, and manufacture of ceramic copings. The aim of this study was therefore to determine whether the Computer Integrated Crown Reconstruction (Cicero) system was compatible with a proposed partial coverage preparation design and capable of producing ceramic copings. Posterior teeth were prepared for partial coverage copings with deep gingival chamfers in the proximal boxes and around the functional cusps (buccal of mandibular and lingual of maxillary posterior teeth). The nonfunctional cusps (lingual of mandibular and buccal of maxillary posterior teeth) were prepared with broad bevels following the inclined occlusal plane pattern. Optical impressions were taken of stone dies by means of a fast laser-line scanning method that measured the three-dimensional geometry of the partial coverage preparation. Computers digitized the images, and designed and produced the ceramic copings. The Cicero system digitized the partial coverage preparation surfaces precisely with a minor coefficient of variance of 0.2%. The accuracy of the surface digitization, the design, and the computer aided milling showed that the system was capable of producing partial coverage copings with a mean marginal gap of 74 microns. This value was obtained before optimizing the marginal fit by means of porcelain veneering. In summary, Cicero computer technology, i.e., surface digitization, coping design, and manufacture, was compatible with the described partial coverage preparations for posterior teeth. PMID:11351490

  3. Coherent-mode decomposition of partially polarized, partially coherent sources

    NASA Astrophysics Data System (ADS)

    Gori, Franco; Santarsiero, Massimo; Simon, Raja; Piquero, Gemma; Borghi, Riccardo; Guattari, Giorgio

    2003-01-01

    It is shown that any partially polarized, partially coherent source can be expressed in terms of a suitable superposition of transverse coherent modes with orthogonal polarization states. Such modes are determined through the solution of a system of two coupled integral equations. An example, for which the modal decomposition is obtained in closed form in terms of fully linearly polarized Hermite Gaussian modes, is given.

  4. Coherent-mode decomposition of partially polarized, partially coherent sources.

    PubMed

    Gori, Franco; Santarsiero, Massimo; Simon, Raja; Piquero, Gemma; Borghi, Riccardo; Guattari, Giorgio

    2003-01-01

    It is shown that any partially polarized, partially coherent source can be expressed in terms of a suitable superposition of transverse coherent modes with orthogonal polarization states. Such modes are determined through the solution of a system of two coupled integral equations. An example, for which the modal decomposition is obtained in closed form in terms of fully linearly polarized Hermite Gaussian modes, is given. PMID:12542320

  5. Aerodynamic Effects in Weakly Ionized Gas: Phenomenology and Applications

    SciTech Connect

    Popovic, S.; Vuskovic, L.

    2006-12-01

    Aerodynamic effects in ionized gases, often neglected phenomena, have been subject of a renewed interest in recent years. After a brief historical account, we discuss a selected number of effects and unresolved problems that appear to be relevant in both aeronautic and propulsion applications in subsonic, supersonic, and hypersonic flow. Interaction between acoustic shock waves and weakly ionized gas is manifested either as plasma-induced shock wave dispersion and acceleration or as shock-wave induced double electric layer in the plasma, followed by the localized increase of the average electron energy and density, as well as enhancement of optical emission. We describe the phenomenology of these effects and discuss several experiments that still do not have an adequate interpretation. Critical for application of aerodynamic effects is the energy deposition into the flow. We classify and discuss some proposed wall-free generation schemes with respect to the efficiency of energy deposition and overall generation of the aerodynamic body force.

  6. Preparing attosecond coherences by strong-field ionization

    NASA Astrophysics Data System (ADS)

    Pabst, Stefan; Lein, Manfred; Wörner, Hans Jakob

    2016-02-01

    Strong-field ionization (SFI) has been shown to prepare wave packets with few-femtosecond periods. Here, we explore whether this technique can be extended to the attosecond time scale. We introduce an intuitive model, which is based on the Fourier transform of the subcycle SFI rate, for predicting the bandwidth of ionic states that can be coherently prepared by SFI. The coherent bandwidth decreases considerably with increasing central wavelength of the ionizing pulse but it is much less sensitive to its intensity. Many-body calculations based on time-dependent configuration-interaction singles support these results. The influence of channel interactions and laser-induced dynamics within the ion is discussed. Our results further predict that multicycle femtosecond pulses can coherently prepare subfemtosecond wave packets with higher selectivity and versatility compared to single-cycle pulses with an additional sensitivity to the mutual parity of the prepared states.

  7. Electron- and photon-impact ionization of furfural

    SciTech Connect

    Jones, D. B.; Ali, E.; Madison, D. H. E-mail: madison@mst.edu; Nixon, K. L.; Limão-Vieira, P. E-mail: madison@mst.edu; Hubin-Franskin, M.-J.; Delwiche, J.; Ning, C. G.; Colgan, J.; Murray, A. J.; and others

    2015-11-14

    The He(I) photoelectron spectrum of furfural has been investigated, with its vibrational structure assigned for the first time. The ground and excited ionized states are assigned through ab initio calculations performed at the outer-valence Green’s function level. Triple differential cross sections (TDCSs) for electron-impact ionization of the unresolved combination of the 4a″  +  21a′ highest and next-highest occupied molecular orbitals have also been obtained. Experimental TDCSs are recorded in a combination of asymmetric coplanar and doubly symmetric coplanar kinematics. The experimental TDCSs are compared to theoretical calculations, obtained within a molecular 3-body distorted wave framework that employed either an orientation average or proper TDCS average. The proper average calculations suggest that they may resolve some of the discrepancies regarding the angular distributions of the TDCS, when compared to calculations employing the orbital average.

  8. Electron- and photon-impact ionization of furfural

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; Ali, E.; Nixon, K. L.; Limão-Vieira, P.; Hubin-Franskin, M.-J.; Delwiche, J.; Ning, C. G.; Colgan, J.; Murray, A. J.; Madison, D. H.; Brunger, M. J.

    2015-11-01

    The He(i) photoelectron spectrum of furfural has been investigated, with its vibrational structure assigned for the first time. The ground and excited ionized states are assigned through ab initio calculations performed at the outer-valence Green's function level. Triple differential cross sections (TDCSs) for electron-impact ionization of the unresolved combination of the 4a″ + 21a' highest and next-highest occupied molecular orbitals have also been obtained. Experimental TDCSs are recorded in a combination of asymmetric coplanar and doubly symmetric coplanar kinematics. The experimental TDCSs are compared to theoretical calculations, obtained within a molecular 3-body distorted wave framework that employed either an orientation average or proper TDCS average. The proper average calculations suggest that they may resolve some of the discrepancies regarding the angular distributions of the TDCS, when compared to calculations employing the orbital average.

  9. Microwave remote sensing of ionized air.

    SciTech Connect

    Liao, S.; Gopalsami, N.; Heifetz, A.; Elmer, T.; Fiflis, P.; Koehl, E. R.; Chien, H. T.; Raptis, A. C.

    2011-07-01

    We present observations of microwave scattering from ambient room air ionized with a negative ion generator. The frequency dependence of the radar cross section of ionized air was measured from 26.5 to 40 GHz (Ka-band) in a bistatic mode with an Agilent PNA-X series (model N5245A) vector network analyzer. A detailed calibration scheme is provided to minimize the effect of the stray background field and system frequency response on the target reflection. The feasibility of detecting the microwave reflection from ionized air portends many potential applications such as remote sensing of atmospheric ionization and remote detection of radioactive ionization of air.

  10. Ultraviolet femtosecond laser ionization mass spectrometry.

    PubMed

    Imasaka, Totaro

    2008-01-01

    For this study, multiphoton ionization/mass spectrometry using an ultraviolet (UV) femtosecond laser was employed for the trace analysis of organic compounds. Some of the molecules, such as dioxins, contain several chlorine atoms and have short excited-state lifetimes due to a "heavy atom" effect. A UV femtosecond laser is, then, useful for efficient resonance excitation and subsequent ionization. A technique of multiphoton ionization using an extremely short laser pulse (e.g., <10 fs), referred to as "impulsive ionization," may have a potential for use in fragmentation-free ionization, thus providing information on molecular weight in mass spectrometry. PMID:18302290

  11. The Contribution of Ionizing Stars to the Far-Infrared and Radio Emission in the Galaxy

    NASA Technical Reports Server (NTRS)

    Terebey, S.; Fich, M.; Taylor, R.

    1999-01-01

    A summary of research activities carried out in this eighth and final progress report. The final report includes: this summary document, copies of three published research papers, plus a draft manuscript of a fourth research paper entitled "The Contribution of Ionizing Stars to the FarInfrared and Radio Emission in the Milky Way; Evidence for a Swept-up Shell and Diffuse Ionized Halo around the W4 Chimney/Supershell." The main activity during the final quarterly reporting period was research on W4, including analysis of the radio and far-infrared images, generation of shell models, a literature search, and preparation of a research manuscript. There will be additional consultation with co-authors prior to submission of the paper to the Astrophysical Journal. The results will be presented at the 4th Tetons Summer Conference on "Galactic Structure, Stars, and the ISM" in May 2000. In this fourth and last paper we show W4 has a swept-up partially ionized shell of gas and dust which is powered by the OCl 352 star cluster. Analysis shows there is dense interstellar material directly below the shell, evidence that that the lower W4 shell "ran into a brick wall" and stalled, whereas the upper W4 shell achieved "breakout" to form a Galactic chimney. An ionized halo is evidence of Lyman continuum leakage which ionizes the WIM (warm ionized medium). It has long been postulated that the strong winds and abundant ionizing photons from massive stars are responsible for much of the large scale structure in the interstellar medium (ISM), including the ISM in other galaxies. However standard HII region theory predicts few photons will escape the local HII region. The significance of W4 and this work is it provides a direct example of how stellar winds power a galactic chimney, which in turn leads to a low density cavity from which ionizing photons can escape to large distances to ionize the WIM.

  12. Highly ionized xenon and volumetric weighting in restricted focal geometries

    NASA Astrophysics Data System (ADS)

    Strohaber, J.; Kolomenskii, A. A.; Schuessler, H. A.

    2015-08-01

    The ionization of xenon atoms subjected to 42 fs, 800 nm pulses of radiation from a Ti:Sapphire laser was investigated. In our experiments, a maximum laser intensity of ˜ 2 × 10 15 W / cm 2 was used. Xenon ions were measured using a time-of-flight ion mass spectrometer having an entrance slit with dimensions of 12 μ m × 400 μ m . The observed yields Xe n + ( n = 1 - 7 ) were partially free of spatial averaging. The ion yields showed sequential and nonsequential multiple ionization and dip structures following saturation. To investigate the dip structures and to perform a comparison between experimental and simulated data, with the goal of clarifying the effects of residual spatial averaging, we derived a hybrid analytical-numerical solution for the integration kernel in restricted focal geometries. We simulated xenon ionization using Ammosov-Delone-Krainov and Perelomov-Popov-Terent'ev theories and obtained agreement with the results of observations. Since a large number of experiments suffer from spatial averaging, the results presented are important to correctly interpret experimental data by taking into account spatial averaging.

  13. Resonant- and avalanche-ionization amplification of laser-induced plasma in air

    SciTech Connect

    Wu, Yue; Zhang, Zhili; Jiang, Naibo; Roy, Sukesh; Gord, James R.

    2014-10-14

    Amplification of laser-induced plasma in air is demonstrated utilizing resonant laser ionization and avalanche ionization. Molecular oxygen in air is ionized by a low-energy laser pulse employing (2 + 1) resonance-enhanced multi-photon ionization (REMPI) to generate seed electrons. Subsequent avalanche ionization of molecular oxygen and nitrogen significantly amplifies the laser-induced plasma. In this plasma-amplification effect, three-body attachments to molecular oxygen dominate the electron-generation and -loss processes, while either nitrogen or argon acts as the third body with low electron affinity. Contour maps of the electron density within the plasma obtained in O₂/N₂ and O₂/Ar gas mixtures are provided to show relative degrees of plasma amplification with respect to gas pressure and to verify that the seed electrons generated by O₂ 2 + 1 REMPI are selectively amplified by avalanche ionization of molecular nitrogen in a relatively low-pressure condition (≤100 Torr). Such plasma amplification occurring in air could be useful in aerospace applications at high altitude.

  14. Low-density ionization behavior

    SciTech Connect

    Baker, G.A. Jr.

    1995-04-01

    As part of a continuing study of the physics of matter under extreme conditions, I give some results on matter at extremely low density. In particular I compare a quantum mechanical calculation of the pressure for atomic hydrogen with the corresponding pressure given by Thomas-Fermi theory. (This calculation differs from the ``confined atom`` approximation in a physically significant way.) Since Thomas-Fermi theory in some sense, represents the case of infinite nuclear charge, these cases should represent extremes. Comparison is also made with Saha theory, which considers ionization from a chemical point of view, but is weak on excited-state effects. In this theory, the pressure undergoes rapid variation as electron ionization levels are passed. This effect is in contrast to the smooth behavior of the Thomas-Fermi fixed temperature, complete ionization occurs in the low density limit, I study the case where the temperature goes appropriately to zero with the density. Although considerable modification is required, Saha theory is closer to the actual results for this case than is Thomas-Fermi theory.

  15. Theory of dissociative tunneling ionization

    NASA Astrophysics Data System (ADS)

    Svensmark, Jens; Tolstikhin, Oleg I.; Madsen, Lars Bojer

    2016-05-01

    We present a theoretical study of the dissociative tunneling ionization process. Analytic expressions for the nuclear kinetic energy distribution of the ionization rates are derived. A particularly simple expression for the spectrum is found by using the Born-Oppenheimer (BO) approximation in conjunction with the reflection principle. These spectra are compared to exact non-BO ab initio spectra obtained through model calculations with a quantum mechanical treatment of both the electronic and nuclear degrees of freedom. In the regime where the BO approximation is applicable, imaging of the BO nuclear wave function is demonstrated to be possible through reverse use of the reflection principle, when accounting appropriately for the electronic ionization rate. A qualitative difference between the exact and BO wave functions in the asymptotic region of large electronic distances is shown. Additionally, the behavior of the wave function across the turning line is seen to be reminiscent of light refraction. For weak fields, where the BO approximation does not apply, the weak-field asymptotic theory describes the spectrum accurately.

  16. Ionization coefficients in gas mixtures

    NASA Astrophysics Data System (ADS)

    Marić, D.; Šašić, O.; Jovanović, J.; Radmilović-Rađenović, M.; Petrović, Z. Lj.

    2007-03-01

    We have tested the application of the common E/N ( E—electric field, N—gas number density) or Wieland approximation [Van Brunt, R.J., 1987. Common parametrizations of electron transport, collision cross section, and dielectric strength data for binary gas mixtures. J. Appl. Phys. 61 (5), 1773-1787.] and the common mean energy (CME) combination of the data for pure gases to obtain ionization coefficients for mixtures. Test calculations were made for Ar-CH4, Ar-N2, He-Xe and CH4-N2 mixtures. Standard combination procedure gives poor results in general, due to the fact that the electron energy distribution is considerably different in mixtures and in individual gases at the same values of E/N. The CME method may be used for mixtures of gases with ionization coefficients that do not differ by more than two orders of magnitude which is better than any other technique that was proposed [Marić, D., Radmilović-Rađenović, M., Petrović, Z.Lj., 2005. On parametrization and mixture laws for electron ionization coefficients. Eur. Phys. J. D 35, 313-321.].

  17. Polarization phenomena in multiphoton ionization of atoms

    NASA Technical Reports Server (NTRS)

    Jacobs, V. L.

    1973-01-01

    The theory of multiphoton ionization for an atomic system of arbitrary complexity is developed using a density matrix formalism. An expression is obtained which determines the differential N-photon ionization cross section as a function of the polarization states of the target atom and the incident radiation. The parameters which characterize the photoelectron angular distribution are related to the general reduced matrix elements for the N-photon transition. Two-photon ionization of unpolarized atoms is treated as an illustration of the use of the theory. The dependence of the multiphoton ionization cross section on the polarization state of the incident radiation, which has been observed in two- and three-photon ionization of Cs, is accounted for by the theory. Finally, the photoelectron spin polarization produced by the multiphoton ionization of unpolarized atoms, like the analogous polarization resulting from single-photon ionization, is found to depend on the circular polarization of the incident radiation.

  18. Relativistic ionization fronts in gas jets

    NASA Astrophysics Data System (ADS)

    Lemos, Nuno; Dias, J. M.; Gallacher, J. G.; Issac, R. C.; Fonseca, R. A.; Lopes, N. C.; Silva, L. O.; Mendonça, J. T.; Jaroszynski, D. A.

    2006-10-01

    A high-power ultra-short laser pulse propagating through a gas jet, ionizes the gas by tunnelling ionization, creating a relativistic plasma-gas interface. The relativistic ionization front that is created can be used to frequency up-shift electromagnetic radiation either in co-propagation or in counter-propagation configurations. In the counter-propagation configuration, ionization fronts can act as relativistic mirrors for terahertz radiation, leading to relativistic double Doppler frequency up-shift to the visible range. In this work, we identified and explored, the parameters that optimize the key features of relativistic ionization fronts for terahertz radiation reflection. The relativistic ionization front generated by a high power laser (TOPS) propagating in a supersonic gas jet generated by a Laval nozzle has been fully characterized. We have also performed detailed two-dimensional relativistic particle-in-cell simulations with Osiris 2.0 to analyze the generation and propagation of the ionization fronts.

  19. Dissociation mechanisms of the Ar trimer induced by a third atom in high-energy electron-impact ionization

    NASA Astrophysics Data System (ADS)

    Yan, S.; Zhang, P.; Ma, X.; Xu, S.; Tian, S. X.; Li, B.; Zhu, X. L.; Feng, W. T.; Zhao, D. M.

    2014-06-01

    We experimentally studied the dissociation dynamics of a highly charged Ar3 cluster initiated by a high-energy electron. The dissociation patterns of the correlated ions from a two-body and a three-body Coulombic explosion (CE) of (Ar3)2+ suggest that predissociation alters the evolution of radiative charge transfer. The three-body CE in (Ar3)4+ and (Ar3)5+ is driven, after double ionization of one constituent Ar atom, by single ionization with a simultaneous interatomic Coulombic decay process.

  20. Shock Structure Analysis and Aerodynamics in a Weakly Ionized Gas Flow

    NASA Technical Reports Server (NTRS)

    Saeks, R.; Popovic, S.; Chow, A. S.

    2006-01-01

    The structure of a shock wave propagating through a weakly ionized gas is analyzed using an electrofluid dynamics model composed of classical conservation laws and Gauss Law. A viscosity model is included to correctly model the spatial scale of the shock structure, and quasi-neutrality is not assumed. A detailed analysis of the structure of a shock wave propagating in a weakly ionized gas is presented, together with a discussion of the physics underlying the key features of the shock structure. A model for the flow behind a shock wave propagating through a weakly ionized gas is developed and used to analyze the effect of the ionization on the aerodynamics and performance of a two-dimensional hypersonic lifting body.

  1. Valence ionized states of iron pentacarbonyl and eta5-cyclopentadienyl cobalt dicarbonyl studied by symmetry-adapted cluster-configuration interaction calculation and collision-energy resolved Penning ionization electron spectroscopy.

    PubMed

    Fukuda, Ryoichi; Ehara, Masahiro; Nakatsuji, Hiroshi; Kishimoto, Naoki; Ohno, Koichi

    2010-02-28

    Valence ionized states of iron pentacarbonyl Fe(CO)(5) and eta(5)-cyclopentadienyl cobalt dicarbonyl Co(eta(5)-C(5)H(5))(CO)(2) have been studied by ultraviolet photoelectron spectroscopy, two-dimensional Penning ionization electron spectroscopy (2D-PIES), and symmetry-adapted cluster-configuration interaction calculations. Theory provided reliable assignments for the complex ionization spectra of these molecules, which have metal-carbonyl bonds. Theoretical ionization energies agreed well with experimental observations and the calculated wave functions could explain the relative intensities of PIES spectra. The collision-energy dependence of partial ionization cross sections (CEDPICS) was obtained by 2D-PIES. To interpret these CEDPICS, the interaction potentials between the molecules and a Li atom were examined in several coordinates by calculations. The relation between the slope of the CEDPICS and the electronic structure of the ionized states, such as molecular symmetry and the spatial distribution of ionizing orbitals, was analyzed. In Fe(CO)(5), an attractive interaction was obtained for the equatorial CO, while the interaction for the axial CO direction was repulsive. For Co(eta(5)-C(5)H(5))(CO)(2), the interaction potential in the direction of both Co-C-O and Co-Cp ring was attractive. These anisotropic interactions and ionizing orbital distributions consistently explain the relative slopes of the CEDPICS. PMID:20192297

  2. Femtosecond Laser Ionization of Organic Amines with Very Low Ionization Potential.

    NASA Astrophysics Data System (ADS)

    Yatsuhashi, Tomoyuki; Obayashi, Takashi; Tanaka, Michinori; Murakami, Masanao; Nakashima, Nobuaki

    2006-03-01

    The interaction between high intensity femtosecond laser and molecules is one of the most attractive areas in laser chemistry and ionization is the most fundamental subject. Theoretical consideration successfully reproduced the ionization behavior of rare gases. However, the understanding of ionization mechanisms of large molecules is difficult more than those of rare gases due to their complexity. Generally speaking, molecules are harder to ionize than rare gases even if they have the same ionization potential. The suppressed ionization phenomena are one of the important features of molecular ionization. Hankin et al. examined 23 organic molecules with ionization potentials between 8.25 and 11.52 eV. We have examined ionization and/ or fragmentation of many organic molecules, including aromatic compounds, halogenated compounds, methane derivatives etc. at various wavelengths below 10^16 Wcm-2. In order to investigate the nature of molecular ionization, it is interesting to examine a variety of molecule in a wide range of ionization potential. In this study, we examined several organic amines because we can explore the uninvestigated ionization potential range down to 5.95 eV. In addition to the significant suppression of the ionization rates, stepwise ionization behavior, which was not observed in rare gases, was observed.

  3. Investigation of ionization mechanism of extended narrow line region.

    NASA Astrophysics Data System (ADS)

    Hashimoto, T. H.; Iye, M. I.; Aoki, K. A.

    2006-08-01

    The narrow line regions of active galaxies have the potential to provide key information about the nature of the central energy sources, the triggering and fueling of the activity, and the dynamical and/or chemical evolution of the narrow line region (NLR). However, if we are to use them in this way, it is crucial to understand the dominant physical mechanism of emission line region. Since Dopita et al.1995,1996 suggested that their radiative shock model is capable of explaining to some extent the spectrum of Seyfert 2 galaxies, detailed observations of individual NLR or extended narrow line region (ENLR) have been performed to clarify the actual ionization mechanism for individual object. It is probably fair to say that at present time, although individual studies may favor gas models photoionized by nonthermal power law photons or other ionization scenario, no clear-cut answer has yet emerged. For the purpose of investigating the importance of shock ionization around NLR we performed optical long-slit spectroscopic observation of Seyfert 2 galaxy, NGC7319, using Subaru telescope during guaranteed time of Faint Object Camera And Spectrograph (FOCAS). We confirmed that NGC7319 has the ENLR (~4kpc) with relatively good alignment with radio components and found the distribution of observed regions in the "diagnostic diagrams"(line ratio versus line ratio plot) are approximately consistent with radiative shock ionization models which assumed about shock front velocity of 500km/s. In addition we discovered the clear anti-corelation between the indicators of gas excitation ([OIII]5007/ Hbeta and [SII](6716+6731)/Halpha) and velocity dispersion over whole observed ENLR. Any other photoionization model could not explain gas kinematics-excitation relation and this anti-corelation is strong evidence of radiative shock ionization, which is probably induced by interaction between jet plasma and NLR clouds. The evidence of the importance of jet-induced shock ionization even

  4. Solving Partial Differential Equations on Overlapping Grids

    SciTech Connect

    Henshaw, W D

    2008-09-22

    We discuss the solution of partial differential equations (PDEs) on overlapping grids. This is a powerful technique for efficiently solving problems in complex, possibly moving, geometry. An overlapping grid consists of a set of structured grids that overlap and cover the computational domain. By allowing the grids to overlap, grids for complex geometries can be more easily constructed. The overlapping grid approach can also be used to remove coordinate singularities by, for example, covering a sphere with two or more patches. We describe the application of the overlapping grid approach to a variety of different problems. These include the solution of incompressible fluid flows with moving and deforming geometry, the solution of high-speed compressible reactive flow with rigid bodies using adaptive mesh refinement (AMR), and the solution of the time-domain Maxwell's equations of electromagnetism.

  5. A partial pelvis of Australopithecus sediba.

    PubMed

    Kibii, Job M; Churchill, Steven E; Schmid, Peter; Carlson, Kristian J; Reed, Nichelle D; de Ruiter, Darryl J; Berger, Lee R

    2011-09-01

    The fossil record of the hominin pelvis reflects important evolutionary changes in locomotion and parturition. The partial pelves of two individuals of Australopithecus sediba were reconstructed from previously reported finds and new material. These remains share some features with australopiths, such as large biacetabular diameter, small sacral and coxal joints, and long pubic rami. The specimens also share derived features with Homo, including more vertically oriented and sigmoid-shaped iliac blades, greater robusticity of the iliac body, sinusoidal anterior iliac borders, shortened ischia, and more superiorly oriented pubic rami. These derived features appear in a species with a small adult brain size, suggesting that the birthing of larger-brained babies was not driving the evolution of the pelvis at this time. PMID:21903805

  6. Laparoscopic total and partial nephrectomy.

    PubMed

    Lee, Benjamin R

    2002-01-01

    Laparoscopic radical nephrectomy has established its role as a standard of care for the management of renal neoplasms. Long term follow-up has demonstrated laparoscopic radical nephrectomy has shorter patient hospitalization and effective cancer control, with no significant difference in survival compared with open radical nephrectomy. For renal masses less than 4cm, partial nephrectomy is indicated for patients with a solitary kidney or who demonstrate impairment of contralateral renal function. The major technical issue for success of laparoscopic partial nephrectomy is bleeding control and several techniques have been developed to achieve better hemostatic control. Development of new laparoscopic techniques for partial nephrectomy can be divided into 2 categories: hilar control and warm ischemia vs. no hilar control. Development of a laparoscopic Satinsky clamp has achieved en bloc control of the renal hilum in order to allow cold knife excision of the mass, with laparoscopic repair of the collecting system, if needed. Combination of laparoscopic partial nephrectomy with ablative techniques has achieved successful excision of renal masses with adequate hemostasis without hilar clamping. Other techniques without hilar control have been investigated and included the use of a microwave tissue coagulator. In conclusion, laparoscopic radical nephrectomy for renal cell carcinoma has clearly demonstrated low morbidity and equivalent cancer control. The rates for local recurrences and metastatic spread are low and actuarial survival high. Furthermore, laparoscopic partial nephrectomy has demonstrated to be technically feasible, with low morbidity. With short term outcomes demonstrating laparoscopic partial nephrectomy as an efficacious procedure, the role of laparoscopic partial nephrectomy should continue to increase. PMID:15748397

  7. Complete characterization of partially coherent and partially polarized optical fields.

    PubMed

    Basso, Gabriel; Oliveira, Luimar; Vidal, Itamar

    2014-03-01

    We suggest a method to access the second-order, or two-point, Stokes parameters of a partially coherent and partially polarized Gaussian model optical field from an intensity interferometry experiment. Through a remarkably simple experimental arrangement, it is possible to measure the two-point and one-point Stokes parameters simultaneously, allowing the reconstruction of the coherence matrix and the polarization matrix, thus completely characterizing the optical field both statistically and locally on the observation plane. Developments, automation, and applications are pointed out. PMID:24690711

  8. Termination of the solar wind in the hot, partially ionized interstellar medium. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Lombard, C. K.

    1974-01-01

    Theoretical foundations for understanding the problem of the termination of the solar wind are reexamined in the light of most recent findings concerning the states of the solar wind and the local interstellar medium. The investigation suggests that a simple extention of Parker's (1961) analytical model provides a useful approximate description of the combined solar wind, interstellar wind plasma flowfield under conditions presently thought to occur. A linear perturbation solution exhibiting both the effects of photoionization and charge exchange is obtained for the supersonic solar wind. A numerical algorithm is described for computing moments of the non-equilibrium hydrogen distribution function and associated source terms for the MHD equations. Computed using the algorithm in conjunction with the extended Parker solution to approximate the plasma flowfield, profiles of hydrogen number density are given in the solar wind along the upstream and downstream axes of flow with respect to the direction of the interstellar wind. Predictions of solar Lyman-alpha backscatter intensities to be observed at 1 a.u. have been computed, in turn, from a set of such hydrogen number density profiles varied over assumed conditions of the interstellar wind.

  9. Elastic scattering of low energy electrons in partially ionized dense semiclassical plasma

    SciTech Connect

    Dzhumagulova, K. N. Shalenov, E. O.; Ramazanov, T. S.

    2015-08-15

    Elastic scattering of electrons by hydrogen atoms in a dense semiclassical hydrogen plasma for low impact energies has been studied. Differential scattering cross sections were calculated within the effective model of electron-atom interaction taking into account the effect of screening as well as the quantum mechanical effect of diffraction. The calculations were carried out on the basis of the phase-function method. The influence of the diffraction effect on the Ramsauer–Townsend effect was studied on the basis of a comparison with results made within the effective polarization model of the Buckingham type.

  10. First principles calculation of the effect of Coulomb collisions in partially ionized gases

    SciTech Connect

    Donkó, Z.

    2014-04-15

    Coulomb collisions, at appreciable ratios (η) of the electron to the neutral particle density, influence significantly the electron kinetics in particle swarms and in plasmas of gas discharges. This paper introduces a combination of Molecular Dynamics and Monte Carlo simulation techniques, to provide a novel, approximation-free, first principles calculation method for the velocity distribution function of electrons, and related swarm characteristics, at arbitrary η. Simulation results are presented for electrons in argon gas, for density ratios between zero and 10{sup −1}, representing the limits of a negligible electron density and an almost complete Maxwellization of the velocity distribution function, respectively.

  11. Ionizing Radiation and Its Risks

    PubMed Central

    Goldman, Marvin

    1982-01-01

    Penetrating ionizing radiation fairly uniformly puts all exposed molecules and cells at approximately equal risk for deleterious consequences. Thus, the original deposition of radiation energy (that is, the dose) is unaltered by metabolic characteristics of cells and tissue, unlike the situation for chemical agents. Intensely ionizing radiations, such as neutrons and alpha particles, are up to ten times more damaging than sparsely ionizing sources such as x-rays or gamma rays for equivalent doses. Furthermore, repair in cells and tissues can ameliorate the consequences of radiation doses delivered at lower rates by up to a factor of ten compared with comparable doses acutely delivered, especially for somatic (carcinogenic) and genetic effects from x- and gamma-irradiation exposure. Studies on irradiated laboratory animals or on people following occupational, medical or accidental exposures point to an average lifetime fatal cancer risk of about 1 × 10-4 per rem of dose (100 per 106 person-rem). Leukemia and lung, breast and thyroid cancer seem more likely than other types of cancer to be produced by radiation. Radiation exposures from natural sources (cosmic rays and terrestrial radioactivity) of about 0.1 rem per year yield a lifetime cancer risk about 0.1 percent of the normally occurring 20 percent risk of cancer death. An increase of about 1 percent per rem in fatal cancer risk, or 200 rem to double the “background” risk rate, is compared with an estimate of about 100 rem to double the genetic risk. Newer data suggest that the risks for low-level radiation are lower than risks estimated from data from high exposures and that the present 5 rem per year limit for workers is adequate. PMID:6761969

  12. XUV ionization of aligned molecules

    SciTech Connect

    Kelkensberg, F.; Siu, W.; Gademann, G.; Rouzee, A.; Vrakking, M. J. J.; Johnsson, P.; Lucchini, M.; Lucchese, R. R.

    2011-11-15

    New extreme-ultraviolet (XUV) light sources such as high-order-harmonic generation (HHG) and free-electron lasers (FELs), combined with laser-induced alignment techniques, enable novel methods for making molecular movies based on measuring molecular frame photoelectron angular distributions. Experiments are presented where CO{sub 2} molecules were impulsively aligned using a near-infrared laser and ionized using femtosecond XUV pulses obtained by HHG. Measured electron angular distributions reveal contributions from four orbitals and the onset of the influence of the molecular structure.

  13. The Tevatron Ionization Profile Monitors

    SciTech Connect

    Jansson, A.; Fitzpatrick, T.; Bowie, K.; Kwarciany, R.; Lundberg, C.; Slimmer, D.; Valerio, L.; Zagel, J.; /Fermilab

    2006-05-01

    In designing an ionization profile monitor system for the Tevatron some novel approaches were taken, in particular for the readout electronics. This was motivated by the desire to resolve the individual bunches in both beams simultaneously. For this purpose, custom made electronics originally developed for Particle Physics experiments was used to provide a fast charge integration with very low noise. The various parts of the read-out electronics have been borrowed or adapted from the KTev, CMS, MINOS and BTev experiments. The detector itself also had to be modified to provide clean signals with sufficient bandwidth. The system design will be described along with the initial results.

  14. Advanced Thin Ionization Calorimeter (ATIC)

    NASA Technical Reports Server (NTRS)

    Wefel, John P.

    1998-01-01

    This is the final report for NASA grant NAGW-4577, "Advanced Thin Ionization Calorimeter (ATIC)". This grant covered a joint project between LSU and the University of Maryland for a Concept Study of a new type of fully active calorimeter to be used to measure the energy spectra of very high energy cosmic rays, particularly Hydrogen and Helium, to beyond 1014 eV. This very high energy region has been studied with emulsion chamber techniques, but never investigated with electronic calorimeters. Technology had advanced to the point that a fully active calorimeter based upon Bismuth Germanate (BGO) scintillating crystals appeared feasible for balloon flight (and eventually space) experiments.

  15. Optical Detection of Tunneling Ionization

    SciTech Connect

    Verhoef, Aart J.; Mitrofanov, Alexander V.; Kartashov, Daniil V.; Baltuska, Andrius

    2010-04-23

    We have experimentally detected optical harmonics that are generated due to a tunneling-ionization-induced modulation of the electron density. The optical signature of electron tunneling can be isolated from concomitant optical responses by using a noncollinear pump-probe setup. Whereas previously demonstrated tools for attosecond metrology of gases, plasmas, and surfaces rely on direct detection of charged particles, detection of the background-free time-resolved optical signal, which uniquely originates from electron tunneling, offers an interesting alternative that is especially suited for systems in which free electrons cannot be directly measured.

  16. Sexual Function after Partial Penectomy: A Prospectively Study From China.

    PubMed

    Yu, Cui; Hequn, Chen; Longfei, Liu; Minfeng, Chen; Zhi, Chen; Feng, Zeng; Jinbo, Chen; Lin, Qi; Xiongbing, Zu

    2016-01-01

    The Purpose of this study was to evaluate the sexual function after partial penectomy for penile carcinoma patients. Between January 2010 and May 2013, patients treated with partial penectomy at our institution were prospectively enrolled in this study. Sexual function (IIEF-15), age, body mass index, penile length in the flaccid state after partial penectomy (PL), treatment, having a partner and psychological factors (SAS scores and SDS scores) were assessed. Univariate and multivariate linear regression analyses were performed. 43 patients were included in our study. The median age was 56 years, and the median PL was 4 cm. The preoperative IIEF-15, SAS, SDS scores were significantly different from the postoperative scores. There was no statistically significant difference between the patients treated with partial penectomy and partial penectomy+ lymphadenectomy on IIEF-15 scores. Age was negatively associated with erectile function, sexual desire, and overall satisfaction; PL was positively associated with intercourse satisfaction; SAS score was negatively associated with erectile function, orgasmic function, sexual desire, and intercourse satisfaction. Our preliminary findings suggest that the sexual function after partial penectomy was significantly reduced. The sexual function was negatively affected by age and anxiety but positively affected by PL. PMID:26902397

  17. Sexual Function after Partial Penectomy: A Prospectively Study From China

    PubMed Central

    Yu, Cui; Hequn, Chen; Longfei, Liu; Minfeng, Chen; Zhi, Chen; Feng, Zeng; Jinbo, Chen; Lin, Qi; Xiongbing, Zu

    2016-01-01

    The Purpose of this study was to evaluate the sexual function after partial penectomy for penile carcinoma patients. Between January 2010 and May 2013, patients treated with partial penectomy at our institution were prospectively enrolled in this study. Sexual function (IIEF-15), age, body mass index, penile length in the flaccid state after partial penectomy (PL), treatment, having a partner and psychological factors (SAS scores and SDS scores) were assessed. Univariate and multivariate linear regression analyses were performed. 43 patients were included in our study. The median age was 56 years, and the median PL was 4 cm. The preoperative IIEF-15, SAS, SDS scores were significantly different from the postoperative scores. There was no statistically significant difference between the patients treated with partial penectomy and partial penectomy+ lymphadenectomy on IIEF-15 scores. Age was negatively associated with erectile function, sexual desire, and overall satisfaction; PL was positively associated with intercourse satisfaction; SAS score was negatively associated with erectile function, orgasmic function, sexual desire, and intercourse satisfaction. Our preliminary findings suggest that the sexual function after partial penectomy was significantly reduced. The sexual function was negatively affected by age and anxiety but positively affected by PL. PMID:26902397

  18. Landsliding in partially saturated materials

    USGS Publications Warehouse

    Godt, J.W.; Baum, R.L.; Lu, N.

    2009-01-01

    [1] Rainfall-induced landslides are pervasive in hillslope environments around the world and among the most costly and deadly natural hazards. However, capturing their occurrence with scientific instrumentation in a natural setting is extremely rare. The prevailing thinking on landslide initiation, particularly for those landslides that occur under intense precipitation, is that the failure surface is saturated and has positive pore-water pressures acting on it. Most analytic methods used for landslide hazard assessment are based on the above perception and assume that the failure surface is located beneath a water table. By monitoring the pore water and soil suction response to rainfall, we observed shallow landslide occurrence under partially saturated conditions for the first time in a natural setting. We show that the partially saturated shallow landslide at this site is predictable using measured soil suction and water content and a novel unified effective stress concept for partially saturated earth materials. Copyright 2009 by the American Geophysical Union.

  19. Partial integration raises antitrust concerns.

    PubMed

    Brock, T H; Kamoie, B E

    2000-11-01

    Recently, providers have begun to explore a new model of integrated delivery system, the partially integrated IDS. Typically, a partially integrated IDS is a joint venture, owned by a core group of providers that maintains complete financial and operational independence outside the joint venture. The IDS contracts with other providers to furnish services that the part-owners do not furnish. A partially integrated IDS raises antitrust concerns because the participating providers may be seen as competitors banding together to set prices jointly for healthcare services. Therefore, to minimize their antitrust exposure, providers that are considering this model should be careful to structure the IDS in accordance with the relevant Federal antitrust laws (i.e., Section 1 of the Sherman Act), taking into account the Federal antitrust agencies' various guidelines and enforcement policies. PMID:11688054

  20. Partial Priapism Treated with Pentoxifylline

    PubMed Central

    Cooper, Meghan A.; Carrion, Rafael E.; Yang, Christopher

    2015-01-01

    ABSTRACT Main findings: A 26-year-old man suffering from partial priapism was successfully treated with a regimen including pentoxifylline, a nonspecific phosphodiesterase inhibitor that is often used to conservatively treat Peyronie's disease. Case hypothesis: Partial priapism is an extremely rare urological condition that is characterized by thrombosis within the proximal segment of a single corpus cavernosum. There have only been 36 reported cases to date. Although several factors have been associated with this unusual disorder, such as trauma or bicycle riding, the etiology is still not completely understood. Treatment is usually conservative and consists of a non-steroidal anti-inflammatory and anti-thrombotic. Promising future implications: This case report supports the utilization of pentoxifylline in patients with partial priapism due to its anti-fibrogenic and anti-thrombotic properties. PMID:26401875

  1. Atmospheric sampling glow discharge ionization source

    DOEpatents

    McLuckey, Scott A.; Glish, Gary L.

    1989-01-01

    An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above.

  2. Atmospheric sampling glow discharge ionization source

    DOEpatents

    McLuckey, S.A.; Glish, G.L.

    1989-07-18

    An atmospheric sampling glow discharge ionization source that can be used in combination with an analytical instrument which operates at high vacuum, such as a mass spectrometer. The atmospheric sampling glow discharge ionization source comprises a chamber with at least one pair of electrodes disposed therein, an inlet for a gaseous sample to be analyzed and an outlet communicating with an analyzer which operates at subatmospheric pressure. The ionization chamber is maintained at a pressure below atmospheric pressure, and a voltage difference is applied across the electrodes to induce a glow discharge between the electrodes, so that molecules passing through the inlet are ionized by the glow discharge and directed into the analyzer. The ionization source accepts the sample under atmospheric pressure conditions and processes it directly into the high vacuum instrument, bridging the pressure gap and drawing off unwanted atmospheric gases. The invention also includes a method for analyzing a gaseous sample using the glow discharge ionization source described above. 3 figs.

  3. Full and partial gauge fixing

    SciTech Connect

    Shirzad, A.

    2007-08-15

    Gauge fixing may be done in different ways. We show that using the chain structure to describe a constrained system enables us to use either a full gauge, in which all gauged degrees of freedom are determined, or a partial gauge, in which some first class constraints remain as subsidiary conditions to be imposed on the solutions of the equations of motion. We also show that the number of constants of motion depends on the level in a constraint chain in which the gauge fixing condition is imposed. The relativistic point particle, electromagnetism, and the Polyakov string are discussed as examples and full or partial gauges are distinguished.

  4. Partial pressure analysis of plasmas

    SciTech Connect

    Dylla, H.F.

    1984-11-01

    The application of partial pressure analysis for plasma diagnostic measurements is reviewed. A comparison is made between the techniques of plasma flux analysis and partial pressure analysis for mass spectrometry of plasmas. Emphasis is given to the application of quadrupole mass spectrometers (QMS). The interface problems associated with the coupling of a QMS to a plasma device are discussed including: differential-pumping requirements, electromagnetic interferences from the plasma environment, the detection of surface-active species, ion source interactions, and calibration procedures. Example measurements are presented from process monitoring of glow discharge plasmas which are useful for cleaning and conditioning vacuum vessels.

  5. Apparatus for generating partially coherent radiation

    DOEpatents

    Naulleau, Patrick P.

    2005-02-22

    Techniques for generating partially coherent radiation and particularly for converting effectively coherent radiation from a synchrotron to partially coherent EUV radiation suitable for projection lithography.

  6. Strong-Field Ionization of Laser Cooled Li Atoms

    NASA Astrophysics Data System (ADS)

    Sharma, Sachin; Romans, Kevin; Fischer, Daniel

    2016-05-01

    Recently, our understanding of few-body effects has been substantially boosted by the development of intense femto- and attosecond laser sources. Observing the momenta of the fragments of atoms and molecules ionized in these strong fields provided new and before inconceivable insights in molecular and electronic dynamics. Here, we report on a new experiment, where the target atoms (6 Li) are laser cooled and trapped using a magneto optical trap (MOT). Momentum vectors of the target fragments will be measured using a reaction microscope (ReMi). The exclusivity of this setup is a combination of MOT and ReMi, thus dubbed as MOTReMi. Here, the advantages over standard COLTRIMS systems are multifold: Firstly, an unprecedented recoil ion momentum resolution can be achieved, as the target can be prepared at significantly lower temperatures. Second, the atoms can be optically prepared in the ground or in polarized excited states. In a first experimental campaign, studies on single ionization of laser excited and polarized Lithium atoms will be performed with circularly polarized light. This experiment can provide insight into the helicity-dependence of the ionization dynamics as the differences among co- and counter rotating electron and laser field, if any, can be investigated.

  7. Ionizing radiation and orthopaedic prostheses

    NASA Astrophysics Data System (ADS)

    Rimnac, Clare M.; Kurtz, Steven M.

    2005-07-01

    Ultra high molecular weight polyethylene (UHMWPE) materials have been used successfully as one half of the bearing couple (against metallic alloys or ceramics) in total hip and total knee joint replacements for four decades. This review describes the impact of ionizing radiation (used for sterilization and for microstructural modification via crosslinking) on the performance of UHMWPE total joint replacement components. Gamma radiation sterilization in air leads to oxidative degradation of UHMWPE joint components that occurs during shelf-aging and also during in vivo use. Efforts to mitigate oxidative degradation of UHMWPE joint components include gamma radiation sterilization in inert barrier-packaging and processing treatments to reduce free radicals. Ionizing radiation (both gamma and electron-beam) has recently been used to form highly crosslinked UHMWPEs that have better adhesive and abrasive wear resistance than non-crosslinked UHMWPE, thereby potentially improving the long-term performance of total joint replacements. Along with increased wear resistance, however, there are deleterious changes to ductility and fracture resistance of UHMWPE, and an increased risk of fracture of these components remains a clinical concern.

  8. Tunneling Ionization Time Resolved by Backpropagation

    NASA Astrophysics Data System (ADS)

    Ni, Hongcheng; Saalmann, Ulf; Rost, Jan-Michael

    2016-07-01

    We determine the ionization time in tunneling ionization by an elliptically polarized light pulse relative to its maximum. This is achieved by a full quantum propagation of the electron wave function forward in time, followed by a classical backpropagation to identify tunneling parameters, in particular, the fraction of electrons that has tunneled out. We find that the ionization time is close to zero for single active electrons in helium and in hydrogen if the fraction of tunneled electrons is large. We expect our analysis to be essential to quantify ionization times for correlated electron motion.

  9. Tunneling Ionization Time Resolved by Backpropagation.

    PubMed

    Ni, Hongcheng; Saalmann, Ulf; Rost, Jan-Michael

    2016-07-01

    We determine the ionization time in tunneling ionization by an elliptically polarized light pulse relative to its maximum. This is achieved by a full quantum propagation of the electron wave function forward in time, followed by a classical backpropagation to identify tunneling parameters, in particular, the fraction of electrons that has tunneled out. We find that the ionization time is close to zero for single active electrons in helium and in hydrogen if the fraction of tunneled electrons is large. We expect our analysis to be essential to quantify ionization times for correlated electron motion. PMID:27447504

  10. Two-step single-ionization mechanisms

    SciTech Connect

    Boeyen, R. W. van; Doering, J. P.; Watanabe, N.; Cooper, J. W.; Coplan, M. A.; Moore, J. H.

    2006-03-15

    In a recent publication [Phys. Rev. Lett. 92, 233202 (2004)] two different electron impact double ionization (e,3e) mechanisms were identified and the way in which two-electron momentum distributions for atoms and molecules could be obtained by triple coincidence (e,3e) measurements was discussed. The apparatus used detected the two ejected electrons both in and out of the scattering plane at an angle of 45 deg. to the momentum transfer direction in triple coincidence with the scattered electron. Ejected electrons detected out of the scattering plane were shown to be a result of two-step double ionization processes. With the same apparatus we have made double coincidence (e,2e) measurements of electron impact single ionization cross sections for ionization of magnesium 3s (valence) and 2p and 2s (inner) shell electrons at incident energies from 400 to 3000 eV in order to obtain more information about two-step ionization. The experimental results were compared with distorted-wave and plane-wave Born approximations carried out to second order. For the experimental conditions, two-step ionization processes involving one ionizing collision and a second elastic collision with the atomic core are the dominant contribution to the measured cross sections. Calculations are in moderate agreement with the data. The angular distributions of the ionized electrons in these two-step ionizations reflect the initial momentum distributions of the target electrons, a result that is analogous with the earlier (e,3e) measurements.

  11. Ionization probes of molecular structure and chemistry

    SciTech Connect

    Johnson, P.M.

    1993-12-01

    Various photoionization processes provide very sensitive probes for the detection and understanding of the spectra of molecules relevant to combustion processes. The detection of ionization can be selective by using resonant multiphoton ionization or by exploiting the fact that different molecules have different sets of ionization potentials. Therefore, the structure and dynamics of individual molecules can be studied even in a mixed sample. The authors are continuing to develop methods for the selective spectroscopic detection of molecules by ionization, and to use these methods for the study of some molecules of combustion interest.

  12. On the ionization potential of molecular oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Gardner, J. L.

    1974-01-01

    The ionization potential of O2 was measured by the technique of high resolution photoelectron spectroscopy taking into account the influence of rotational structure on the shape of the vibrational bands. A value of 12.071 + or - .001 eV (1027.1 + or - 0.1 A) was found for the ionization potential. A lowering of the ionization potential caused by a branch-head when delta N = -2 gave an appearance potential for ionization of 12.068 + or - .001 eV (1027.4 + or - 0.1 A).

  13. Development of dielectric-barrier-discharge ionization.

    PubMed

    Guo, Cheng'an; Tang, Fei; Chen, Jin; Wang, Xiaohao; Zhang, Sichun; Zhang, Xinrong

    2015-03-01

    Dielectric-barrier-discharge ionization is an ambient-ionization technique. Since its first description in 2007, it has attracted much attention in such fields as biological analysis, food safety, mass-spectrometry imaging, forensic identification, and reaction monitoring for its advantages, e.g., low energy consumption, solvent-free method, and easy miniaturization. In this review a brief introduction to dielectric barrier discharge is provided, and then a detailed introduction to the dielectric-barrier-discharge-ionization technique is given, including instrumentation, applications, and mechanistic studies. Based on the summary of reported work, possible future uses of this type of ionization source are discussed at the end. PMID:25510973

  14. Tunneling ionization time-resolved by backpropagation

    NASA Astrophysics Data System (ADS)

    Ni, Hongcheng; Saalmann, Ulf; Rost, Jan M.; Max-Planck-Institut für Physik komplexer Systeme Team

    2016-05-01

    We determine the ionization time in tunneling ionization by an elliptically polarized light pulse relative to its maximum. This is achieved by a full quantum propagation of the electron wave function forward in time, followed by a classical backpropagation to identify tunneling parameters, in particular the fraction of electrons that has tunneled out. We find, that the ionization time is close to zero for single active electrons in helium and in hydrogen if the fraction of tunneled electrons is large. We expect our analysis to be essential to quantify ionization times for correlated electron motion. This work was supported by Alexander von Humboldt Foundation.

  15. Multiple ionization of xenon by proton impact

    SciTech Connect

    Manson, S.T.; DuBois, R.D.

    1987-12-01

    An experimental and theoretical study of multiple ionization of xenon for 0.2- to 2.0-MeV proton impact was made. Absolute cross sections for producing xenon ions with charges from +1 to +3 were measured, and calculations of subshell cross sections were performed. Experiment and theory are consistent and indicate that multiple ionization of xenon by fast protons occurs via inner-shell ionization. This is in contrast to the lighter noble gases where direct multiple outer shell ionization can be predominant.

  16. Democratic Participation and the Body Politic

    ERIC Educational Resources Information Center

    Standish, Paul

    2005-01-01

    Drawing partial contrasts with Deweyan and poststructuralist approaches, this essay develops an account of democratic participation based upon the work of Stanley Cavell. In particular it explores Cavell's reading of the celebrated treatment of the theme of the body politic in Shakespeare's Coriolanus. The discussion examines what it is that…

  17. Discerning the direct and indirect ionization processes in the photo-double-ionization of 1, 1-C2H2F2 near and above threshold

    NASA Astrophysics Data System (ADS)

    Gaire, B.; Bocharova, I.; Sturm, F. P.; Gehrken, N.; Rist, J.; Belkacem, A.; Weber, Th.; Berry, B.; Zohrabi, M.; Ben-Itzhak, I.; Keiling, M.; Moradmand, A.; Landers, A.; Jahnke, T.; Schoeffler, M.; Sann, H.; Kunitski, M.; Doerner, R.

    2014-05-01

    We have studied the photo-double-ionization of 1, 1-C2H2F2 near and above threshold using linearly polarized single photons (40 to 70eV). Kinematically complete experiments were achieved for the nondissociative ionization (NDI) and all ionic two body break up channels by measuring the electrons and recoil ions in coincidence with the COLd Target Recoil Ion Momentum Spectroscopy (COLTRIMS) method. Using electron-ion and electron-electron energy correlation maps as well as asymmetry parameters and relative angles between the emitted electrons, we were able to trace the electronic states involved and distinguish between the direct and indirect ionization mechanisms of the NDI and the fragmentation processes. Supported by the Director, Office of Science, Office of Basic Energy Sciences, and by the Division of Chemical Sciences, Geosciences, and Biosciences of the U.S. Department of Energy at LBNL under Contract No. DE-AC02-05CH11231.

  18. Investigation of Ionization and Dissociation Processes Produced by Electron Impact on Molecules.

    NASA Astrophysics Data System (ADS)

    Ma, Ce.

    1990-01-01

    Absolute electron impact partial ionization cross sections for Ar and CF_4 were measured by use of a newly built pulsed electron beam time-of-flight apparatus for incident electron energies from thresholds to 500 eV. The apparatus employed consisted of a low energy electron gun, 40 mm diameter ion extraction gold screens, time-of-flight drift tubes, micro-channel plate detectors and fast time to digital electronics. A pulsed electron beam was obtained by pulsing the control grid of the electron gun. Both beam - beam experiments and beam - constant gas target pressure experiments were carried out to determine the absolute partial ionization cross sections for Ar ^{+}, Ar^{2+ }, Ar^{3+} from an argon gas target, and for CF_sp {3}{+}, CF_sp {2}{+}, CF_sp {3}{2+}, CF^ {+}, CF_sp{2} {2+}, F^{+}, C^{+} from a CF _4 gas target. By charge weighted summing of the partial ionization cross sections, the total ionization cross sections of Ar and CF_4 were obtained. The total neutral dissociation cross section for CF_4 was inferred from the total ionization cross section and the total dissociation cross section. Also, a new method for determining absolute total electron scattering cross sections with corrections for forward scattering was developed. The electron beam current was measured as function of gas target pressure and the scattering path length. The total electron scattering cross section obtained from the new model is as much as 6% larger than the cross section derived from the traditional Beer's law for Ar at an incident electron energy of 300 eV. This method is capable of yielding reliable total cross section up to 10 keV. Finally, a study of the secondary electron emission as a function of ejection angle and ejection energy for CO, the doubly differential cross section (DDCS), is presented.

  19. Mitigation Effect of an FGF-2 Peptide on Acute Gastrointestinal Syndrome After High-Dose Ionizing Radiation

    SciTech Connect

    Zhang Lurong; Sun Weimin; Wang Jianjun; Zhang Mei; Yang Shanmin; Tian Yeping; Vidyasagar, Sadasivan; Pena, Louis A.; Zhang Kunzhong; Cao Yongbing; Yin Liangjie; Wang Wei; Zhang Lei; Schaefer, Katherine L.; Saubermann, Lawrence J.; Swarts, Steven G.; Fenton, Bruce M.; Keng, Peter C.; Okunieff, Paul

    2010-05-01

    Purpose: Acute gastrointestinal syndrome (AGS) resulting from ionizing radiation causes death within 7 days. Currently, no satisfactory agent exists for mitigation of AGS. A peptide derived from the receptor binding domain of fibroblast growth factor 2 (FGF-P) was synthesized and its mitigation effect on AGS was examined. Methods and Materials: A subtotal body irradiation (sub-TBI) model was created to induce gastrointestinal (GI) death while avoiding bone marrow death. After 10.5 to 16 Gy sub-TBI, mice received an intramuscular injection of FGF-P (10 mg/kg/day) or saline (0.2 ml/day) for 5 days; survival (frequency and duration) was measured. Crypt cells and their proliferation were assessed by hematoxylin, eosin, and BrdU staining. In addition, GI hemoccult score, stool formation, and plasma levels of endotoxin, insulin, amylase, interleukin (IL)-6, keratinocyte-derived chemokine (KC) monocyte chemoattractant protein 1 (MCP-1) and tumor necrosis factor (TNF)-alpha were evaluated. Results: Treatment with FGF-P rescued a significant fraction of four strains of mice (33-50%) exposed to a lethal dose of sub-TBI. Use of FGF-P improved crypt survival and repopulation and partially preserved or restored GI function. Furthermore, whereas sub-TBI increased plasma endotoxin levels and several pro-inflammation cytokines (IL-6, KC, MCP-1, and TNF-alpha), FGF-P reduced these adverse responses. Conclusions: The study data support pursuing FGF-P as a mitigator for AGS.

  20. Leadership in Partially Distributed Teams

    ERIC Educational Resources Information Center

    Plotnick, Linda

    2009-01-01

    Inter-organizational collaboration is becoming more common. When organizations collaborate they often do so in partially distributed teams (PDTs). A PDT is a hybrid team that has at least one collocated subteam and at least two subteams that are geographically distributed and communicate primarily through electronic media. While PDTs share many…

  1. Threshold for Thermal Ionization of an Aluminum Surface by Pulsed Megagauss Magnetic Field

    SciTech Connect

    Awe, T. J.; Bauer, B. S.; Fuelling, S.; Siemon, R. E.

    2010-01-22

    The first measurement of the threshold for thermal ionization of the surface of thick metal by pulsed magnetic field (B) is reported. Thick aluminum - with depth greater than the magnetic skin layer - was pulsed with partial derivB/partial derivt from 30-80 MG/mus. Novel loads avoided nonthermal plasma (from electron avalanche, or energetic particles or photons from arcs). Thermal plasma forms from 6061-alloy aluminum when the surface magnetic field reaches 2.2 MG, in qualitative agreement with numerical simulation results by Garanin et al.[J. Appl. Mech. Tech. Phys. 46, 153 (2005)].

  2. Ensemble Monte Carlo calculation of the hole initiated impact ionization rate in bulk GaAs and silicon using a k-dependent, numerical transition rate formulation

    NASA Technical Reports Server (NTRS)

    Oguzman, Ismail H.; Wang, Yang; Kolnik, Jan; Brennan, Kevin F.

    1995-01-01

    The hole initiated impact ionization rate in bulk silicon and GaAs is calculated using a numerical formulation of the impact ionization transition rate incorporated into an ensemble Monte Carlo simulation. The transition rate is calculated from Fermi's golden rule using a two-body screened Coulomb interaction including a wavevector dependent dielectric function. It is found that the effective threshold for hole initiated ionization is relatively soft in both materials, that the split-off band dominates the ionization process in GaAs. and that no clear dominance by any one band is observed in silicon, though the rate out of the light hole band is greatest.

  3. The partial-birth stratagem.

    PubMed

    1998-06-01

    In Wisconsin, physicians stopped performing abortions when a Federal District Court Judge refused to issue a temporary restraining order against the state's newly enacted "partial birth" abortion ban that was couched in such vague language it actually covered all abortions. While ostensibly attempting to ban late-term "intact dilation and extraction," the language of the law did not refer to that procedure or to late terms. Instead, it prohibited all abortions in which a physician "partially vaginally delivers a living child, causes the death of the partially delivered child with the intent to kill the child and then completes the delivery of the child." The law also defined "child" as "a human being from the time of fertilization" until birth. It is clear that this abortion ban is unconstitutional under Row v. Wade, and this unconstitutionality is compounded by the fact that the law allowed no exception to protect a woman's health, which is required by Roe for abortion bans after fetal viability. Wisconsin is only one of about 28 states that have enacted similar laws, and only two have restricted the ban to postviability abortions. Many of these laws have been struck down in court, and President Clinton has continued to veto the Federal partial-birth bill. The Wisconsin Judge acknowledged that opponents of the ban will likely prevail when the case is heard, but his action in denying the temporary injunction means that many women in Wisconsin will not receive timely medical care. The partial birth strategy is really only another anti-abortion strategy. PMID:12348556

  4. Multiphoton ionization of uranium hexafluoride

    NASA Astrophysics Data System (ADS)

    Armstrong, D. P.; Harkins, D. A.; Compton, R. N.; Ding, D.

    1994-01-01

    Multiphoton ionization (MPI) time-of-flight mass spectroscopy (TOFMS) and photoelectron spectroscopy (PES) studies of UF6 are reported using focused light from the Nd:YAG laser fundamental (λ=1064 nm) and its harmonics (λ=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF+x fragment ions, even at the lowest laser power densities at which signal could be detected. In general, the doubly charged uranium ion (U2+) intensity is much greater than that of the singly charged uranium ion (U+). For the case of the tunable dye laser experiments, the Un+ (n=1-4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The MPI-PES studies reveal only very slow electrons (≤0.5 eV) for all wavelengths investigated. The dominance of the U2+ ion, the absence or very small intensities of UF+x (x=1-3) fragments, the unstructured wavelength dependence, and the preponderance of slow electrons all indicate that mechanisms may exist other than ionization of bare U atoms following the stepwise photodissociation of F atoms from the parent molecule. The data also argue against stepwise photodissociation of UF+x (x=5,6) ions. Neither of the traditional MPI mechanisms (``neutral ladder'' or the ``ionic ladder'') are believed to adequately describe the ionization phenomena observed. We propose that the multiphoton excitation of UF6 under these experimental conditions results in a highly excited molecule, superexcited UF6**. The excitation of highly excited UF6** is proposed to be facilitated by the well known ``giant resonance,'' whose energy level lies in the range of 12-14 eV above that of ground state UF6. The highly excited molecule then primarily dissociates, via multiple channels, into Un+, UF+x, fluorine atoms, and ``slow'' electrons, although dissociation

  5. IONIZED NITROGEN AT HIGH REDSHIFT

    SciTech Connect

    Decarli, R.; Walter, F.; Neri, R.; Cox, P.; Bertoldi, F.; Carilli, C.; Kneib, J. P.; Lestrade, J. F.; Maiolino, R.; Omont, A.; Richard, J.; Riechers, D.; Thanjavur, K.; Weiss, A.

    2012-06-10

    We present secure [N II]{sub 205{mu}m} detections in two millimeter-bright, strongly lensed objects at high redshift, APM 08279+5255 (z = 3.911) and MM 18423+5938 (z = 3.930), using the IRAM Plateau de Bure Interferometer. Due to its ionization energy [N II]{sub 205{mu}m} is a good tracer of the ionized gas phase in the interstellar medium. The measured fluxes are S([N II]{sub 205{mu}m}) = (4.8 {+-} 0.8) Jy km s{sup -1} and (7.4 {+-} 0.5) Jy km s{sup -1}, respectively, yielding line luminosities of L([N II]{sub 205{mu}m}) = (1.8 {+-} 0.3) Multiplication-Sign 10{sup 9} {mu}{sup -1} L{sub Sun} for APM 08279+5255 and L([N II]{sub 205{mu}m}) = (2.8 {+-} 0.2) Multiplication-Sign 10{sup 9} {mu}{sup -1} L{sub Sun} for MM 18423+5938. Our high-resolution map of the [N II]{sub 205{mu}m} and 1 mm continuum emission in MM 18423+5938 clearly resolves an Einstein ring in this source and reveals a velocity gradient in the dynamics of the ionized gas. A comparison of these maps with high-resolution EVLA CO observations enables us to perform the first spatially resolved study of the dust continuum-to-molecular gas surface brightness ({Sigma}{sub FIR}{proportional_to}{Sigma}{sup N}{sub CO}, which can be interpreted as the star formation law) in a high-redshift object. We find a steep relation (N = 1.4 {+-} 0.2), consistent with a starbursting environment. We measure a [N II]{sub 205{mu}m}/FIR luminosity ratio in APM 08279+5255 and MM 18423+5938 of 9.0 Multiplication-Sign 10{sup -6} and 5.8 Multiplication-Sign 10{sup -6}, respectively. This is in agreement with the decrease of the [N II]{sub 205{mu}m}/FIR ratio at high FIR luminosities observed in local galaxies.

  6. Propagation of dust-acoustic waves in weakly ionized plasmas with dust-charge fluctuation

    NASA Astrophysics Data System (ADS)

    Mondal, K. K.

    2004-11-01

    For an unmagnetized partially ionized dusty plasma containing electrons, singly charged positive ions, micron-sized massive negatively charged dust grains and a fraction of neutral atoms, dispersion relations for both the dust-ion-acoustic and the dust- acoustic waves have been derived, incorporating dust charge fluctuation. The dispersion relations, under various conditions, have been exhaustively analysed. The explicit expres- sions for the growth rates have also been derived.

  7. Ionization in nearby interstellar gas

    NASA Technical Reports Server (NTRS)

    Frisch, P. C.; Welty, D. E.; York, D. G.; Fowler, J. R.

    1990-01-01

    Due to dielectric recombination, neutral magnesium represents an important tracer for the warm low-density gas around the solar system. New Mg I 2852 absorption-line data from IUE are presented, including detections in a few stars within 40 pc of the sun. The absence of detectable Mg I in Alpha CMa and other stars sets limits on the combined size and electron density of the interstellar cloud which gives rise to the local interstellar wind. For a cloud radius greater than 1 pc and density of 0.1/cu cm, the local cloud has a low fractional ionization, n(e)/n(tot) less than 0.05, if magnesium is undepleted, equilibrium conditions prevail, the cloud temperature is 11,750 K, and 80 percent of the magnesium in the sightline is Mg II.

  8. Ionization tube simmer current circuit

    DOEpatents

    Steinkraus, Jr., Robert F.

    1994-01-01

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

  9. Ionization tube simmer current circuit

    DOEpatents

    Steinkraus, R.F. Jr.

    1994-12-13

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current. 6 figures.

  10. Device for detecting ionizing radiation

    SciTech Connect

    Anatychuk, L.I.; Kharitonov, J.P.; Kusniruk, V.F.; Meir, V.A.; Melnik, A.P.; Ponomarev, V.S.; Skakodub, V.A.; Sokolov, A.D.; Subbotin, V.G.; Zhukovsky, A.N.

    1980-10-28

    The present invention relates to ionizing radiation sensors, and , more particularly, to semiconductor spectrometers with thermoelectric cooling, and can most advantageously be used in mineral raw material exploration and evaluation under field conditions. The spectrometer comprises a vacuum chamber with an entrance window for passing the radiation therethrough. The vacuum chamber accommodates a thermoelectric cooler formed by a set of peltier elements. A heat conducting plate is mounted on the cold side of the thermoelectric cooler, and its hot side is provided with a radiator. Mounted on the heat conducting plate are sets of peltier elements, integral with the thermoelectric cooler and independent of one another. The peltier elements of these sets are stacked so as to develop the minimum temperature conditions on one set carrying a semiconductor detector and to provide the maximum refrigeration capacity conditions on the other set provided with the field-effect transistor mounted thereon.

  11. Electrospray Ionization on Solid Substrates

    PubMed Central

    So, Pui-Kin; Hu, Bin; Yao, Zhong-Ping

    2014-01-01

    Development of electrospray ionization on solid substrates (solid-substrate ESI) avoids the clogging problem encountered in conventional capillary-based ESI, allows more convenient sampling and permits new applications. So far, solid-substrate ESI with various materials, e.g., metals, paper, wood, fibers and biological tissue, has been developed, and applications ranging from analysis of pure compounds to complex mixtures as well as in vivo study were demonstrated. Particularly, the capability of solid-substrate ESI in direct analysis of complex samples, e.g., biological fluids and foods, has significantly facilitated mass spectrometric analysis in real-life applications and led to increasingly important roles of these techniques nowadays. In this review, various solid-substrate ESI techniques and their applications are summarized and the prospects in this field are discussed. PMID:26819900

  12. Weakly ionized cerium plasma radiography

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Hayasi, Yasuomi; Germer, Rudolf; Koorikawa, Yoshitake; Murakami, Kazunori; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Ichimaru, Toshio; Obata, Fumiko; Takahashi, Kiyomi; Sato, Sigehiro; Takayama, Kazuyoshi; Ido, Hideaki

    2004-02-01

    In the plasma flash x-ray generator, high-voltage main condenser of about 200 nF is charged up to 55 kV by a power supply, and electric charges in the condenser are discharged to an x-ray tube after triggering the cathode electrode. The flash x-rays are then produced. The x-ray tube is of a demountable triode that is connected to a turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to a rod cerium target of 3.0 mm in diameter by electric field in the x-ray tube, the weakly ionized linear plasma, which consists of cerium ions and electrons, forms by target evaporating. At a charging voltage of 55 kV, the maximum tube voltage was almost equal to the charging voltage of the main condenser, and the peak current was about 20 kA. When the charging voltage was increased, weakly ionized cerium plasma formed, and the K-series characteristic x-ray intensities increased. The x-ray pulse widths were about 500 ns, and the time-integrated x-ray intensity had a value of about 40 μC/kg at 1.0 m from x-ray source with a charging voltage of 55 kV. In the angiography, we employed a film-less computed radiography (CR) system and iodine-based microspheres. Because K-series characteristic x-rays are absorbed easily by the microspheres, high-contrast angiography has been performed.

  13. 29 CFR 1926.53 - Ionizing radiation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Protection Against Radiation (10 CFR part 20), relating to protection against occupational radiation exposure... 29 Labor 8 2011-07-01 2011-07-01 false Ionizing radiation. 1926.53 Section 1926.53 Labor... § 1926.53 Ionizing radiation. (a) In construction and related activities involving the use of sources...

  14. Ultrafast ionization and fragmentation of molecular silane

    SciTech Connect

    Sayres, Scott G.; Ross, Matt W.; Castleman, A. W. Jr.

    2010-09-15

    The ionization and fragmentation of molecular silane is examined here with laser intensities ranging between 7x10{sup 12} and 1x10{sup 15} W/cm{sup 2} at 624 nm. The ionization potential of silane determined using both multiphoton ionization (MPI) and tunneling ionization (TI) models agrees with the vertical ionization potential of the molecule. In addition, the application of the tunneling ionization model is extended here to the fragments of silane to determine their appearance potentials. MPI values for SiH{sub 3}{sup +}, SiH{sub 2}{sup +}, SiH{sup +}, Si{sup +}, as well as H{sub 2}{sup +} and H{sup +} are consistent with vertical potentials, whereas the TI measurements are found to be in accord with adiabatic potentials. The tunneling appearance potentials observed for the fragments H{sub 2}{sup +} and H{sup +} are lower than reported for other techniques. In fact, the appearance potential measurements for these species resulting from silane are lower than their ionization potentials. The fragmentation rate of silane is determined to be nearly 20 times larger than the ionization rate. The main precursor for producing amorphous silicon (a-Si:H) thin films, SiH{sub 3}{sup +} is the dominant fragmentation product making up roughly a third of the total ion yield, a substantial increase from other techniques.

  15. 29 CFR 1926.53 - Ionizing radiation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Protection Against Radiation (10 CFR part 20), relating to protection against occupational radiation exposure... 29 Labor 8 2012-07-01 2012-07-01 false Ionizing radiation. 1926.53 Section 1926.53 Labor... § 1926.53 Ionizing radiation. (a) In construction and related activities involving the use of sources...

  16. Forensic applications of ambient ionization mass spectrometry.

    PubMed

    Ifa, Demian R; Jackson, Ayanna U; Paglia, Giuseppe; Cooks, R Graham

    2009-08-01

    This review highlights and critically assesses forensic applications in the developing field of ambient ionization mass spectrometry. Ambient ionization methods permit the ionization of samples outside the mass spectrometer in the ordinary atmosphere, with minimal sample preparation. Several ambient ionization methods have been created since 2004 and they utilize different mechanisms to create ions for mass-spectrometric analysis. Forensic applications of these techniques--to the analysis of toxic industrial compounds, chemical warfare agents, illicit drugs and formulations, explosives, foodstuff, inks, fingerprints, and skin--are reviewed. The minimal sample pretreatment needed is illustrated with examples of analysis from complex matrices (e.g., food) on various substrates (e.g., paper). The low limits of detection achieved by most of the ambient ionization methods for compounds of forensic interest readily offer qualitative confirmation of chemical identity; in some cases quantitative data are also available. The forensic applications of ambient ionization methods are a growing research field and there are still many types of applications which remain to be explored, particularly those involving on-site analysis. Aspects of ambient ionization currently undergoing rapid development include molecular imaging and increased detection specificity through simultaneous chemical reaction and ionization by addition of appropriate chemical reagents. PMID:19241065

  17. 29 CFR 1910.1096 - Ionizing radiation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 6 2014-07-01 2013-07-01 true Ionizing radiation. 1910.1096 Section 1910.1096 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED) Toxic and Hazardous Substances § 1910.1096 Ionizing radiation. (a)...

  18. MICE: The International Muon Ionization Cooling Experiment

    SciTech Connect

    Kaplan, Daniel M.

    2006-03-20

    Ionization cooling of a muon beam is a key technique for a Neutrino Factory or Muon Collider. An international collaboration is mounting an experiment to demonstrate muon ionization cooling at the Rutherford Appleton Laboratory. We aim to complete the experiment by 2010.

  19. Photoelectron angular distributions in infrared one-photon and two-photon ionization of FEL-pumped Rydberg states of helium

    NASA Astrophysics Data System (ADS)

    Mondal, S.; Fukuzawa, H.; Motomura, K.; Tachibana, T.; Nagaya, K.; Sakai, T.; Matsunami, K.; Yase, S.; Yao, M.; Wada, S.; Hayashita, H.; Saito, N.; Callegari, C.; Prince, K. C.; O'Keeffe, P.; Bolognesi, P.; Avaldi, L.; Miron, C.; Nagasono, M.; Togashi, T.; Yabashi, M.; Ishikawa, K. L.; Sazhina, I. P.; Kazansky, A. K.; Kabachnik, N. M.; Ueda, K.

    2013-10-01

    The photoelectron angular distributions (PADs) have been investigated for infrared (IR) ionization of He atoms excited to Rydberg states by extreme ultraviolet free-electron laser pulses. The experiment was carried out with two pulses which do not overlap in time. Depending on the intensity of the IR pulses, one IR photon ionization or additionally two-photon above-threshold ionization is observed. For low IR intensity, the PAD is well described by a contribution of s and d partial waves in accordance with early experiments. At high IR intensity, the PAD for two IR photon ionization clearly shows the contribution of higher partial waves. The experimental data are compared with the results of theoretical calculations based on solving the time-dependent Schrödinger equation.

  20. Photoionization of Synchrotron-Radiation-Excited Atoms: Separating Partial Cross Sections by Full Polarization Control

    SciTech Connect

    Aloiese, S.; Meyer, M.; Cubaynes, D.; Grum-Grzhimailo, A. N.

    2005-06-10

    Resonant atomic excitation by synchrotron radiation and subsequent ionization by a tunable dye laser is used to study the photoionization of short-lived Rydberg states in Xe. By combining circular and linear polarization of the synchrotron as well as of the laser photons the partial photoionization cross sections were separated in the region of overlapping autoionizing resonances of different symmetry and the parameters of the resonances were extracted.

  1. Introduction to total- and partial-pressure measurements in vacuum systems

    NASA Technical Reports Server (NTRS)

    Outlaw, R. A.; Kern, F. A.

    1989-01-01

    An introduction to the fundamentals of total and partial pressure measurement in the vacuum regime (760 x 10 to the -16th power Torr) is presented. The instrument most often used in scientific fields requiring vacuum measurement are discussed with special emphasis on ionization type gauges and quadrupole mass spectrometers. Some attention is also given to potential errors in measurement as well as calibration techniques.

  2. Ionization Scheme Development at the ISOLDE RILIS

    NASA Astrophysics Data System (ADS)

    Fedosseev, V. N.; Marsh, B. A.; Fedorov, D. V.; Köster, U.; Tengborn, E.

    2005-04-01

    The resonance ionization laser ion source (RILIS) of the ISOLDE on-line isotope separation facility is based on the method of laser step-wise resonance ionization of atoms in a hot metal cavity. The atomic selectivity of the RILIS complements the mass selection process of the ISOLDE separator magnets to provide beams of a chosen isotope with greatly reduced isobaric contamination. Using a system of dye lasers pumped by copper vapour lasers, ion beams of 24 elements have been generated at ISOLDE with ionization efficiencies in the range of 0.5-15%. As part of the ongoing RILIS development off-line resonance ionization spectroscopy studies carried out in 2003 and 2004 have determined the optimal three-step ionization schemes for scandium, antimony, dysprosium and yttrium.

  3. Inner-orbital ionization of iodine

    NASA Astrophysics Data System (ADS)

    Gibson, George; Smith, Dale; Tagliamonti, Vincent; Dragan, James

    2016-05-01

    Many coincidence techniques exist to study multiple ionization of molecules by strong laser fields. However, the first ionization step is critical in many experiments, although it is more difficult to obtain information about this initial step. We studied the single electron ionization of I2, as it presents interesting opportunities in that it is heavy and does not expand significantly during the laser pulse. Moreover, there are several distinct low-lying valence orbitals from which the electron may be removed. Most importantly, the kinetic energy release of the I+ + I dissociation channel can be measured and should correspond to well-known valence levels and separated atom limits. As it turns out, we must invoke deep valence orbits, built from the 5s electrons, to explain our data. Ionization from deep orbitals may be possible, as they have a smaller critical internuclear separation for enhanced ionization. We would like to acknowledge support from the NSF under Grant No. PHY-1306845.

  4. Astatine and Yttrium Resonant Ionization Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Teigelhoefer, Andrea

    Providing intense, contamination-free beams of rare isotopes to experiments is a challenging task. At isotope separator on-line facilities such as ISAC at TRIUMF, the choice of production target and ion source are key to the successful beam delivery. Due to their element-selectivity, high efficiency and versatility, resonant ionization laser ion sources (RILIS) gain increasingly in importance. The spectroscopic data available are typically incomplete in the region of excited- and autoionizing atomic states. In order to find the most efficient ionization scheme for a particular element, further spectroscopy is often required. The development of efficient laser resonant ionization schemes for yttrium and astatine is presented in this thesis. For yttrium, two ionization schemes with comparable relative intensities were found. Since for astatine, only two transitions were known, the focus was to provide data on atomic energy levels using resonance ionization spectroscopy. Altogether 41 previously unknown astatine energy levels were found.

  5. Extreme Ionizing-Radiation-Resistant Bacterium

    NASA Technical Reports Server (NTRS)

    Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

    2013-01-01

    There is a growing concern that desiccation and extreme radiation-resistant, non-spore-forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequent proliferation on another solar body. Such forward contamination would jeopardize future life detection or sample return technologies. The prime focus of NASA s planetary protection efforts is the development of strategies for inactivating resistance-bearing micro-organisms. Eradi cation techniques can be designed to target resistance-conferring microbial populations by first identifying and understanding their physiologic and biochemical capabilities that confers its elevated tolerance (as is being studied in Deinococcus phoenicis, as a result of this description). Furthermore, hospitals, food, and government agencies frequently use biological indicators to ensure the efficacy of a wide range of radiation-based sterilization processes. Due to their resistance to a variety of perturbations, the nonspore forming D. phoenicis may be a more appropriate biological indicator than those currently in use. The high flux of cosmic rays during space travel and onto the unshielded surface of Mars poses a significant hazard to the survival of microbial life. Thus, radiation-resistant microorganisms are of particular concern that can survive extreme radiation, desiccation, and low temperatures experienced during space travel. Spore-forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate these extreme conditions. Since the Viking era, spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Members of the non-sporeforming bacterial community such as Deinococcus radiodurans can survive acute exposures to ionizing radiation (5 kGy), ultraviolet light (1 kJ/m2), and desiccation (years). These resistive phenotypes of Deinococcus enhance the

  6. Extreme Ionizing-Radiation-Resistant Bacterium

    NASA Technical Reports Server (NTRS)

    Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

    2012-01-01

    There is a growing concern that desiccation and extreme radiation-resistant, non-spore-forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequent proliferation on another solar body. Such forward contamination would jeopardize future life detection or sample return technologies. The prime focus of NASA s planetary protection efforts is the development of strategies for inactivating resistance-bearing microorganisms. Eradification techniques can be designed to target resistance-conferring microbial populations by first identifying and understanding their physiologic and biochemical capabilities that confers its elevated tolerance (as is being studied in Deinococcus phoenicis, as a result of this description). Furthermore, hospitals, food, and government agencies frequently use biological indicators to ensure the efficacy of a wide range of radiation- based sterilization processes. Due to their resistance to a variety of perturbations, the non-spore forming D. phoenicis may be a more appropriate biological indicator than those currently in use. The high flux of cosmic rays during space travel and onto the unshielded surface of Mars poses a significant hazard to the survival of microbial life. Thus, radiation-resistant microorganisms are of particular concern that can survive extreme radiation, desiccation, and low temperatures experienced during space travel. Spore-forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate these extreme conditions. Since the Viking era, spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Members of the non-spore-forming bacterial community such as Deinococcus radiodurans can survive acute exposures to ionizing radiation (5 kGy), ultraviolet light (1 kJ/sq m), and desiccation (years). These resistive phenotypes of Deinococcus enhance the

  7. Ghost peaks observed after AP-MALDI experiment may disclose new ionization mechanism of matrix assisted hypersonic velocity impact ionization

    PubMed Central

    Moskovets, Eugene

    2015-01-01

    RATIONALE Understanding the mechanisms of MALDI promises improvements in the sensitivity and specificity of many established applications in the field of mass spectrometry. This paper reports a serendipitous observation of a significant ion yield in a post-ionization experiment conducted after the sample has been removed from a standard atmospheric pressure (AP)-MALDI source. This post-ionization is interpreted in terms of collisions of microparticles moving with a hypersonic velocity into a solid surface. Calculations show that the thermal energy released during such collisions is close to that absorbed by the top matrix layer in traditional MALDI. The microparticles, containing both the matrix and analytes, could be detached from a film produced inside the inlet capillary during the sample ablation and accelerated by the flow rushing through the capillary. These observations contribute some new perspective to ion formation in both laser and laserless matrix-assisted ionization. METHODS An AP-MALDI ion source hyphenated with a three-stage high-pressure ion funnel system was utilized for peptide mass analysis. After the laser was turned off and MALDI sample was removed, ions were detected during a gradual reduction of the background pressure in the first funnel. The constant-rate pressure reduction led to the reproducible appearance of different singly- and doubly-charged peptide peaks in mass spectra taken a few seconds after the end of the MALDI analysis of a dried-droplet spot. RESULTS The ion yield as well as the mass range of ions observed with a significant delay after a completion of the primary MALDI analysis depended primarily on the background pressure inside the first funnel. The production of ions in this post-ionization step was exclusively observed during the pressure drop. A lower matrix background and significant increase in relative yield of double-protonated ions are reported. CONCLUSIONS The observations were partially consistent with a model of

  8. Characterization tests of a homemade ionization chamber in mammography standard radiation beams

    NASA Astrophysics Data System (ADS)

    Silva, J. O.; Nonato, F. B. C.; Caldas, L. V. E.

    2014-02-01

    A mammography homemade ionization chamber was developed to be applied for mammography energy range dosimetry. This chamber has a sensitive volume of 6 cm3 and is made of a Lucite body and graphite coated collecting electrode. Characteristics such as saturation, ion collection efficiency, linearity of chamber response versus air kerma rate and energy dependence were determined. The results obtained with the mammography homemade ionization chamber are within the limits stated in international recommendations. This chamber can be used in quality control programs in the diagnostic radiology area. All measurements were carried out at the Calibration Laboratory of IPEN.

  9. Convergent close-coupling calculations of helium single ionization by antiproton impact

    SciTech Connect

    Abdurakhmanov, I. B.; Kadyrov, A. S.; Fursa, D. V.; Bray, I.; Stelbovics, A. T.

    2011-12-15

    We apply the fully quantum-mechanical convergent close-coupling method to the calculation of antiproton scattering on the ground state of helium. The helium target is treated as a three-body Coulomb system using frozen-core and multiconfiguration approximations. The electron-electron correlation of the target is fully treated in both cases. Though both calculations yield generally good agreement with experiment for the total ionization cross sections, the multiconfiguration results are substantially higher at the lower energies than the frozen-core ones. Calculated longitudinal ejected electron and recoil-ion momentum distributions for the single ionization of helium are in good agreement with the experiment.

  10. Lattice-Boltzmann simulation of laser interaction with weakly ionized helium plasmas

    SciTech Connect

    Li Huayu; Ki, Hyungson

    2010-07-15

    This paper presents a lattice Boltzmann method for laser interaction with weakly ionized plasmas considering electron impact ionization and three-body recombination. To simulate with physical properties of plasmas, the authors' previous work on the rescaling of variables is employed and the electromagnetic fields are calculated from the Maxwell equations by using the finite-difference time-domain method. To calculate temperature fields, energy equations are derived separately from the Boltzmann equations. In this way, we attempt to solve the full governing equations for plasma dynamics. With the developed model, the continuous-wave CO{sub 2} laser interaction with helium is simulated successfully.

  11. Wettability of partially suspended graphene.

    PubMed

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T; Checco, Antonio

    2016-01-01

    The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle. PMID:27072195

  12. Wettability of partially suspended graphene

    DOE PAGESBeta

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-04-13

    Dependence on the wettability of graphene on the nature of the underlying substrate remains only partially understood. We systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Moreover, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquidmore » interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.« less

  13. Wettability of partially suspended graphene

    PubMed Central

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-01-01

    The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle. PMID:27072195

  14. Partial hydatidiform mole: ultrasonographic features.

    PubMed

    Woo, J S; Hsu, C; Fung, L L; Ma, H K

    1983-05-01

    Four patients with partial hyatidiform mole managed at the Queen Mary Hospital, Hong Kong, are described. The diagnosis of blighted ovum or missed abortion was made on the sonographic findings prior to suction evacuation. The dominant features in these cases consisted of a relatively large central transonic area bearing the appearance of an empty gestational sac and surrounded by a thick rim of low-level placenta-like echoes; in contrast with the case of the blighted ovum, a well-defined echogenic sac wall is absent. In another 9 patients with molar pregnancy managed during the same period, the more typical 'snow-storm' vesicular appearance was present. It was concluded that the anembryonic appearance described should alert the sonologist and clinician to the possible diagnosis of partial hydatitiform mole. The evacuated material from the uterine cavity should be examined morphologically and if possible cytogenetically. PMID:6578773

  15. Wettability of partially suspended graphene

    NASA Astrophysics Data System (ADS)

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-04-01

    The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.

  16. Partial stabilization-based guidance.

    PubMed

    Shafiei, M H; Binazadeh, T

    2012-01-01

    A novel nonlinear missile guidance law against maneuvering targets is designed based on the principles of partial stability. It is demonstrated that in a real approach which is adopted with actual situations, each state of the guidance system must have a special behavior and asymptotic stability or exponential stability of all states is not realistic. Thus, a new guidance law is developed based on the partial stability theorem in such a way that the behaviors of states in the closed-loop system are in conformity with a real guidance scenario that leads to collision. The performance of the proposed guidance law in terms of interception time and control effort is compared with the sliding mode guidance law by means of numerical simulations. PMID:21963401

  17. The Inhibitory Effects of Low-Dose Ionizing Radiation in IgE-Mediated Allergic Responses

    PubMed Central

    Nam, Seon Young; Yang, Kwang Hee; Kim, Cha Soon; Lee, In Kyung; Kim, Ji Young

    2015-01-01

    Ionizing radiation has different biological effects according to dose and dose rate. In particular, the biological effect of low-dose radiation is unclear. Low-dose whole-body gamma irradiation activates immune responses in several ways. However, the effects and mechanism of low-dose radiation on allergic responses remain poorly understood. Previously, we reported that low-dose ionizing radiation inhibits mediator release in IgE-mediated RBL-2H3 mast cell activation. In this study, to have any physiological relevance, we investigated whether low-dose radiation inhibits allergic responses in activated human mast cells (HMC-1(5C6) and LAD2 cells), mouse models of passive cutaneous anaphylaxis and the late-phase cutaneous response. High-dose radiation induced cell death, but low-dose ionizing radiation of <0.5 Gy did not induce mast cell death. Low-dose ionizing radiation that did not induce cell death significantly suppressed mediator release from human mast cells (HMC-1(5C6) and LAD2 cells) that were activated by antigen-antibody reaction. To determine the inhibitory mechanism of mediator released by low-dose ionizing radiation, we examined the phosphorylation of intracellular signaling molecules such as Lyn, Syk, phospholipase Cγ, and protein kinase C, as well as the intracellular free Ca2+ concentration ([Ca2+]i). The phosphorylation of signaling molecules and [Ca2+]i following stimulation of FcεRI receptors was inhibited by low dose ionizing radiation. In agreement with its in vitro effect, ionizing radiation also significantly inhibited inflammatory cells infiltration, cytokine mRNA expression (TNF-α, IL-4, IL-13), and symptoms of passive cutaneous anaphylaxis reaction and the late-phase cutaneous response in anti-dinitrophenyl IgE-sensitized mice. These results indicate that ionizing radiation inhibits both mast cell-mediated immediate- and delayed-type allergic reactions in vivo and in vitro. PMID:26317642

  18. The Inhibitory Effects of Low-Dose Ionizing Radiation in IgE-Mediated Allergic Responses.

    PubMed

    Joo, Hae Mi; Kang, Su Jin; Nam, Seon Young; Yang, Kwang Hee; Kim, Cha Soon; Lee, In Kyung; Kim, Ji Young

    2015-01-01

    Ionizing radiation has different biological effects according to dose and dose rate. In particular, the biological effect of low-dose radiation is unclear. Low-dose whole-body gamma irradiation activates immune responses in several ways. However, the effects and mechanism of low-dose radiation on allergic responses remain poorly understood. Previously, we reported that low-dose ionizing radiation inhibits mediator release in IgE-mediated RBL-2H3 mast cell activation. In this study, to have any physiological relevance, we investigated whether low-dose radiation inhibits allergic responses in activated human mast cells (HMC-1(5C6) and LAD2 cells), mouse models of passive cutaneous anaphylaxis and the late-phase cutaneous response. High-dose radiation induced cell death, but low-dose ionizing radiation of <0.5 Gy did not induce mast cell death. Low-dose ionizing radiation that did not induce cell death significantly suppressed mediator release from human mast cells (HMC-1(5C6) and LAD2 cells) that were activated by antigen-antibody reaction. To determine the inhibitory mechanism of mediator released by low-dose ionizing radiation, we examined the phosphorylation of intracellular signaling molecules such as Lyn, Syk, phospholipase Cγ, and protein kinase C, as well as the intracellular free Ca2+ concentration ([Ca2+]i). The phosphorylation of signaling molecules and [Ca2+]i following stimulation of FcεRI receptors was inhibited by low dose ionizing radiation. In agreement with its in vitro effect, ionizing radiation also significantly inhibited inflammatory cells infiltration, cytokine mRNA expression (TNF-α, IL-4, IL-13), and symptoms of passive cutaneous anaphylaxis reaction and the late-phase cutaneous response in anti-dinitrophenyl IgE-sensitized mice. These results indicate that ionizing radiation inhibits both mast cell-mediated immediate- and delayed-type allergic reactions in vivo and in vitro. PMID:26317642

  19. Electron impact ionization and multiphoton ionization of doped superfluid helium droplets: A comparison

    NASA Astrophysics Data System (ADS)

    He, Yunteng; Zhang, Jie; Kong, Wei

    2016-02-01

    We compare characteristics of electron impact ionization (EI) and multiphoton ionization (MPI) of doped superfluid helium droplets using the same droplet source. Selected dopant ion fragments from the two ionization schemes demonstrate different dependence on the doping pressure, which could be attributed to the different ionization mechanisms. While EI directly ionizes helium atoms in a droplet therefore has higher yields for bigger droplets (within a limited size range), MPI is insensitive to the helium in a droplet and is only dependent on the number of dopant molecules. The optimal timing of the ionization pulse also varies with the doping pressure, implying a velocity slip among different sized droplets. Calculations of the doping statistics and ionization probabilities qualitatively agree with the experimental data. Our results offer a word of caution in interpreting the pressure and timing dependence of superfluid helium droplets, and we also devise a scheme in achieving a high degree of doping while limiting the contribution of dopant clusters.

  20. Electron impact ionization and multiphoton ionization of doped superfluid helium droplets: A comparison.

    PubMed

    He, Yunteng; Zhang, Jie; Kong, Wei

    2016-02-28

    We compare characteristics of electron impact ionization (EI) and multiphoton ionization (MPI) of doped superfluid helium droplets using the same droplet source. Selected dopant ion fragments from the two ionization schemes demonstrate different dependence on the doping pressure, which could be attributed to the different ionization mechanisms. While EI directly ionizes helium atoms in a droplet therefore has higher yields for bigger droplets (within a limited size range), MPI is insensitive to the helium in a droplet and is only dependent on the number of dopant molecules. The optimal timing of the ionization pulse also varies with the doping pressure, implying a velocity slip among different sized droplets. Calculations of the doping statistics and ionization probabilities qualitatively agree with the experimental data. Our results offer a word of caution in interpreting the pressure and timing dependence of superfluid helium droplets, and we also devise a scheme in achieving a high degree of doping while limiting the contribution of dopant clusters. PMID:26931697

  1. MULTI-FLUID SIMULATIONS OF CHROMOSPHERIC MAGNETIC RECONNECTION IN A WEAKLY IONIZED REACTING PLASMA

    SciTech Connect

    Leake, James E.; Lukin, Vyacheslav S.; Linton, Mark G.; Meier, Eric T.

    2012-12-01

    We present results from the first self-consistent multi-fluid simulations of chromospheric magnetic reconnection in a weakly ionized reacting plasma. We simulate two-dimensional magnetic reconnection in a Harris current sheet with a numerical model which includes ion-neutral scattering collisions, ionization, recombination, optically thin radiative loss, collisional heating, and thermal conduction. In the resulting tearing mode reconnection the neutral and ion fluids become decoupled upstream from the reconnection site, creating an excess of ions in the reconnection region and therefore an ionization imbalance. Ion recombination in the reconnection region, combined with Alfvenic outflows, quickly removes ions from the reconnection site, leading to a fast reconnection rate independent of Lundquist number. In addition to allowing fast reconnection, we find that these non-equilibria partial ionization effects lead to the onset of the nonlinear secondary tearing instability at lower values of the Lundquist number than has been found in fully ionized plasmas. These simulations provide evidence that magnetic reconnection in the chromosphere could be responsible for jet-like transient phenomena such as spicules and chromospheric jets.

  2. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Forgings, castings and machined bodies. 121.10... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as...

  3. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Forgings, castings and machined bodies. 121.10... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as...

  4. Directed Evolution of Ionizing Radiation Resistance in Escherichia coli▿ †

    PubMed Central

    Harris, Dennis R.; Pollock, Steve V.; Wood, Elizabeth A.; Goiffon, Reece J.; Klingele, Audrey J.; Cabot, Eric L.; Schackwitz, Wendy; Martin, Joel; Eggington, Julie; Durfee, Timothy J.; Middle, Christina M.; Norton, Jason E.; Popelars, Michael C.; Li, Hao; Klugman, Sarit A.; Hamilton, Lindsay L.; Bane, Lukas B.; Pennacchio, Len A.; Albert, Thomas J.; Perna, Nicole T.; Cox, Michael M.; Battista, John R.

    2009-01-01

    We have generated extreme ionizing radiation resistance in a relatively sensitive bacterial species, Escherichia coli, by directed evolution. Four populations of Escherichia coli K-12 were derived independently from strain MG1655, with each specifically adapted to survive exposure to high doses of ionizing radiation. D37 values for strains isolated from two of the populations approached that exhibited by Deinococcus radiodurans. Complete genomic sequencing was carried out on nine purified strains derived from these populations. Clear mutational patterns were observed that both pointed to key underlying mechanisms and guided further characterization of the strains. In these evolved populations, passive genomic protection is not in evidence. Instead, enhanced recombinational DNA repair makes a prominent but probably not exclusive contribution to genome reconstitution. Multiple genes, multiple alleles of some genes, multiple mechanisms, and multiple evolutionary pathways all play a role in the evolutionary acquisition of extreme radiation resistance. Several mutations in the recA gene and a deletion of the e14 prophage both demonstrably contribute to and partially explain the new phenotype. Mutations in additional components of the bacterial recombinational repair system and the replication restart primosome are also prominent, as are mutations in genes involved in cell division, protein turnover, and glutamate transport. At least some evolutionary pathways to extreme radiation resistance are constrained by the temporally ordered appearance of specific alleles. PMID:19502398

  5. Absolute electron-impact total ionization cross sections of chlorofluoromethanes

    NASA Astrophysics Data System (ADS)

    Martínez, Roberto; Sierra, Borja; Redondo, Carolina; Rayo, María N. Sánchez; Castaño, Fernando

    2004-12-01

    An experimental study is reported on the electron-impact total ionization cross sections (TICSs) of CCl4, CCl3F, CCl2F2, and CClF3 molecules. The kinetic energy of the colliding electrons was in the 10-85 eV range. TICSs were obtained as the sum of the partial ionization cross sections of all fragment ions, measured and identified in a linear double focusing time-of-flight mass spectrometer. The resulting TICS profiles—as a function of the electron-impact energy—have been compared both with those computed by ab initio and (semi)empirical methods and with the available experimental data. The computational methods used include the binary-encounter-Bethe (BEB) modified to include atoms with principal quantum numbers n⩾3, the Deutsch and Märk (DM) formalism, and the modified additivity rule (MAR). It is concluded that both modified BEB and DM methods fit the experimental TICS for (CF4), CClF3, CCl2F2, CCl3F, and CCl4 to a high accuracy, in contrast with the poor accord of the MAR method. A discussion on the factors influencing the discrepancies of the fittings is presented.

  6. High-Resolution Emission-Line Imaging of Seyfert Galaxies. II. Evidence for Anisotropic Ionizing Radiation

    NASA Astrophysics Data System (ADS)

    Wilson, Andrew S.; Ward, Martin J.; Haniff, Christopher A.

    1988-11-01

    In the preceding paper, we describe a direct imaging survey of Seyfert galaxies with "linear" radio structures and find that the major axes and spatial scales of the circumnuclear emission-line gas are very similar to those of the radio continuum sources. In the present paper, the nature of this close connection between thermal and relativistic gases is assessed in detail. Models in which the kinetic energy of the radio jets or plasmoids powers shock waves, which ionize the gas, seem energetically feasible but disagree with the off-nuclear line intensity ratios. Ionization by relativistic electrons is negligible, but they may contribute to the heating of the gas. We favor a scenario in which the radio jets and plasmoids shock, accelerate, and compress ambient and entrained gas, but the dominant source of ionization is the nonstellar nuclear ultraviolet continuum. This ultraviolet source appears to be partially beamed along the axis of the radio jet. Photoionization by ultraviolet synchrotron radiation generated via shocks in the ejecta may also contribute, especially in Seyfert 2 galaxies. A comparison between the number of ionizing photons, N_i_, inferred by extrapolation of the directly observed continuum, and the number of ionizing photons, N_Hβ_, required to generate the Hβ emission has been made for six galaxies in our sample. In at least two galaxies, we find N_i_ << N_Hβ_, suggesting that the gas is exposed to a higher ionizing flux than inferred from direct observations of the nucleus, and supporting the idea of partial beaming. Similarly, the energy in the continuum between 100 A and 1 micron, if emitted isotropically, is inadequate to fuel the thermal nuclear infrared sources, implying that the radiating dust is heated by a more luminous optical-ultraviolet source. We speculate that the nuclear infrared emission of Seyfert 2 galaxies arises from dust in molecular clouds exposed to the partially beamed radiation, and we predict that the 10 micron

  7. REVIEW: Development of methods for body composition studies

    NASA Astrophysics Data System (ADS)

    Mattsson, Sören; Thomas, Brian J.

    2006-07-01

    This review is focused on experimental methods for determination of the composition of the human body, its organs and tissues. It summarizes the development and current status of fat determinations from body density, total body water determinations through the dilution technique, whole and partial body potassium measurements for body cell mass estimates, in vivo neutron activation analysis for body protein measurements, dual-energy absorptiometry (DEXA), computed tomography (CT) and magnetic resonance imaging (MRI, fMRI) and spectroscopy (MRS) for body composition studies on tissue and organ levels, as well as single- and multiple-frequency bioimpedance (BIA) and anthropometry as simple easily available methods. Methods for trace element analysis in vivo are also described. Using this wide range of measurement methods, together with gradually improved body composition models, it is now possible to quantify a number of body components and follow their changes in health and disease.

  8. Lewy Body Disease

    MedlinePlus

    Lewy body disease is one of the most common causes of dementia in the elderly. Dementia is the loss of mental ... to affect normal activities and relationships. Lewy body disease happens when abnormal structures, called Lewy bodies, build ...

  9. Body Composition Tests

    MedlinePlus

    ... more bone and muscle will weigh more in water than a person with less bone and muscle. The volume of the body is calculated and body density and body fat percentage are calculated. This technique ...

  10. Wall temperature control of low-speed body drag

    NASA Technical Reports Server (NTRS)

    Lin, J. C.; Ash, R. L.

    1986-01-01

    The use of thermal means to control drag under turbulent boundary layer conditions is examined. Numerical calculations are presented for both skin friction and (unseparated) pressure drag for turbulent boundary-layer flows over a fuselage-like body with wall heat transfer. In addition, thermal control of separation on a bluff body is investigated. It is shown that a total drag reduction of up to 20 percent can be achieved for wall heating with a wall-to-total-freestream temperature ratio of 2. For streamlined slender bodies, partial wall heating of the forebody can produce almost the same order of total drag reduction as the full body heating case. For bluff bodies, the separation delay from partial wall cooling of the afterbody is approximately the same as for the fully cooled body.

  11. Ionization Cooling using Parametric Resonances

    SciTech Connect

    Johnson, Rolland P.

    2008-06-07

    Ionization Cooling using Parametric Resonances was an SBIR project begun in July 2004 and ended in January 2008 with Muons, Inc., (Dr. Rolland Johnson, PI), and Thomas Jefferson National Accelerator Facility (JLab) (Dr. Yaroslav Derbenev, Subcontract PI). The project was to develop the theory and simulations of Parametric-resonance Ionization Cooling (PIC) so that it could be used to provide the extra transverse cooling needed for muon colliders in order to relax the requirements on the proton driver, reduce the site boundary radiation, and provide a better environment for experiments. During the course of the project, the theoretical understanding of PIC was developed and a final exposition is ready for publication. Workshops were sponsored by Muons, Inc. in May and September of 2007 that were devoted to the PIC technique. One outcome of the workshops was the interesting and somewhat unexpected realization that the beam emittances using the PIC technique can get small enough that space charge forces can be important. A parallel effort to develop our G4beamline simulation program to include space charge effects was initiated to address this problem. A method of compensating for chromatic aberrations by employing synchrotron motion was developed and simulated. A method of compensating for spherical aberrations using beamline symmetry was also developed and simulated. Different optics designs have been developed using the OptiM program in preparation for applying our G4beamline simulation program, which contains all the power of the Geant4 toolkit. However, no PIC channel design that has been developed has had the desired cooling performance when subjected to the complete G4beamline simulation program. This is believed to be the consequence of the difficulties of correcting the aberrations associated with the naturally large beam angles and beam sizes of the PIC method that are exacerbated by the fringe fields of the rather complicated channel designs that have been

  12. Partial discharges and breakdown in C3F8

    NASA Astrophysics Data System (ADS)

    Koch, M.; Franck, C. M.

    2014-10-01

    Traditional search processes of gases or gas mixtures for replacing SF6 involve time consuming measurements of partial discharges and breakdown behaviour for several voltage waveforms and different field configurations. Recently a model for prediction of this behaviour for SF6 was described in literature. The model only requires basic properties of the gas such as the critical field strength and the effective ionization coefficient, which can be obtained by swarm parameter measurements, and thermodynamic properties, which can be calculated. In this paper, we show for the well-known and electronegative gas octafluoropropane (C3F8) that it is possible to transfer the model developed for SF6 to this gas to describe the breakdown behaviour of C3F8. Thus the model can be beneficial in the screening process of new insulation gases.

  13. Establishing Atmospheric Pressure Chemical Ionization Efficiency Scale.

    PubMed

    Rebane, Riin; Kruve, Anneli; Liigand, Piia; Liigand, Jaanus; Herodes, Koit; Leito, Ivo

    2016-04-01

    Recent evidence has shown that the atmospheric pressure chemical ionization (APCI) mechanism can be more complex than generally assumed. In order to better understand the processes in the APCI source, for the first time, an ionization efficiency scale for an APCI source has been created. The scale spans over 5 logIE (were IE is ionization efficiency) units and includes 40 compounds with a wide range of chemical and physical properties. The results of the experiments show that for most of the compounds the ionization efficiency order in the APCI source is surprisingly similar to that in the ESI source. Most of the compounds that are best ionized in the APCI source are not small volatile molecules. Large tetraalkylammonium cations are a prominent example. At the same time, low-polarity hydrocarbons pyrene and anthracene are ionized in the APCI source but not in the ESI source. These results strongly imply that in APCI several ionization mechanisms operate in parallel and a mechanism not relying on evaporation of neutral molecules from droplets has significantly higher influence than commonly assumed. PMID:26943482

  14. Helium Ionization in the Diffuse Ionized Gas surrounding Ultra-compact HII regions

    NASA Astrophysics Data System (ADS)

    Anish Roshi, D.; Churchwell, Edward B.

    2016-01-01

    We observed radio recombination lines (RRLs) from regions surrounding three Ultra-compact HII (UCHII) regions at frequencies near 5 GHz. The observations were made with the Green Bank Telescope (GBT). From existing observations we know that helium in the diffuse ionized gas (DIR), located far from the ionizing source, is not fully ionized. The objectives of our observations are to determine (a) the distance from the ionizing stars where helium is under ionized for a variety of physical conditions and (b) whether the helium ionization depends on the age of the ionizing star. With these objectives, we observed RRLs towards 16 positions in the envelops of UCHII regions G10.15-0.34, G23.46-0.20 and G29.96-0.02. Helium lines were detected toward 10 of the observed positions and hydrogen RRLs were detected toward all the observed positions. The observed ratio of ionized helium to ionized hydrogen (He^+/H^+) at the positions where helium lines are detected range between 0.03 and 0.09. At positions where helium lines are not detected the upper limit on the ratio is ~ 0.05. We discuss the dependence of He^+/H^+ ratio on the distance from and age of the ionizing star clusters in the observed sources.

  15. Non-equilibrium ionized blast wave

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    1974-01-01

    The structure of a cylindrical blast wave with ionization at non-LTE conditions was calculated using equations previously developed by Wu and Fu (1970). The degree of ionization was predicted by a modified Saha equation. Temperature profiles show that the temperature at non-LTE conditions is lower than at LTE near the shock front. This corresponds to a higher degree of ionization for the non-LTE limit, which indicates that the neutral gas absorption is much more efficient at non-LTE than at the LTE limit. The decaying velocity under non-LTE is approximately 15% less than under LTE.

  16. Thermochromic behaviors and ionization potentials of organopolysilanes

    NASA Astrophysics Data System (ADS)

    Yokoyama, Kenji; Yokoyama, Masaaki

    1989-04-01

    Ionization potentials of organopolysilanes with different kinds of substituents were evaluated from the low energy photo-electron emission measurements in air. An aryl-substituted organopolysilane capable of σ - π mixing between Si backbone σ and side-group π electrons gave smaller ionization potential by about 0.1˜0.15 eV compared with alkyl-substituted organopolysilanes. The value of ionization potentials in some alkyl-substituted organopolysilanes which showed thermochromic behaviors was found to vary substantially with thermally induced reversible changes in polymer backbone conformation, indicating that the effective conjugation length of σ electrons decreases above the thermochromic transition temperature.

  17. Probing Angular Correlations in Sequential Double Ionization

    SciTech Connect

    Fleischer, A.; Woerner, H. J.; Arissian, L.; Liu, L. R.; Meckel, M.; Rippert, A.; Doerner, R.; Villeneuve, D. M.; Corkum, P. B.; Staudte, A.

    2011-09-09

    We study electron correlation in sequential double ionization of noble gas atoms and HCl in intense, femtosecond laser pulses. We measure the photoelectron angular distributions of Ne{sup +} relative to the first electron in a pump-probe experiment with 8 fs, 800 nm, circularly polarized laser pulses at a peak intensity of a few 10{sup 15} W/cm{sup 2}. Using a linear-linear pump-probe setup, we further study He, Ar, and HCl. We find a clear angular correlation between the two ionization steps in the sequential double ionization intensity regime.

  18. Ionizing photon budget: constraints from galaxies

    NASA Astrophysics Data System (ADS)

    Östlin, Göran

    2015-08-01

    I will discuss the the production and propagation of ionizing photons in galaxies. Multi wavelength HST imaging and spectroscopy of local starbursts, including candidate Lyman continuum leakers, from the UV to the i-band plus Halpha and Hbeta are used to investigate where ionizing protons are produced and absorbed. We add IFU data, e.g. from MUSE, to further constrain the optical depth to Lyman continuum photons. I will further discuss rest frame UV observations of galaxies at higher redshifts, and their implications for the ionizing photon budget.

  19. Re-ionization and decaying dark matter

    NASA Technical Reports Server (NTRS)

    Dodelson, Scott; Jubas, Jay M.

    1991-01-01

    Gunn-Peterson tests suggest that the Universe was reionized after the standard recombination epoch. A systematic treatment is presented of the ionization process by deriving the Boltzmann equations appropriate to this regime. A compact solution for the photon spectrum is found in terms of the ionization ratio. These equations are then solved numerically for the Decaying Dark Matter scenario, wherein neutrinos with mass of order 30 eV radiatively decay producing photons which ionize the intergalactic medium. It was found that the neutrino mass and lifetime are severely constrained by Gunn-Peterson tests, observations of the diffuse photon spectrum in the ultraviolet regime, and the Hubble parameter.

  20. Epicyclic Twin-Helix Ionization Cooling Simulations

    SciTech Connect

    Vasiliy Morozov, Yaroslav Derbenev, A. Afanaciev, R.P. Johnson

    2011-04-01

    Parametric-resonance Ionization Cooling (PIC) is proposed as the final 6D cooling stage of a highluminosity muon collider. For the implementation of PIC, we earlier developed an epicyclic twin-helix channel with correlated behavior of the horizontal and vertical betatron motions and dispersion. We now insert absorber plates with short energy-recovering units located next to them at the appropriate locations in the twin-helix channel. We first demonstrate conventional ionization cooling in such a system with the optics uncorrelated. We then adjust the correlated optics state and induce a parametric resonance to study ionization cooling under the resonant condition.