Special issue on transient plasmas
NASA Astrophysics Data System (ADS)
Bailey, James; Hoarty, David; Mancini, Roberto; Yoneda, Hitoki
2015-11-01
This special issue of Journal of Physics B: Atomic, Molecular and Optical Physics is dedicated to the "spectroscopy of transient plasmas" covering plasma conditions produced by a range of pulsed laboratory sources including short and long pulse lasers, pulsed power devices, and free electron lasers (FELs). The full range of plasma spectroscopy up to high energy bremsstrahlung radiation, including line broadening analysis for application to data recorded with the ChemCam instrument on the Mars Science Laboratory rover Curiosity, is covered. This issue is timely as advances in optical lasers and x-ray FELs (XFEL) are enabling transient plasma to be probed at higher energies and shorter durations than ever before. New XFEL facilities being commissioned in Europe and Asia are adding to those operating in the US and Japan and the ELI high power laser project in Europe, due to open this year, will provide short pulse lasers of unprecedented power. This special issue represents a snapshot of the theoretical and experimental research in dense plasmas, electron kinetics, laser-induced breakdown spectroscopy of low temperature plasmas, inertial confinement fusion and non-equilibrium atomic physics using spectroscopy to diagnose plasmas produced by optical lasers, XFELs and pulsed-power machines.
Special topics in plasma confinement
NASA Astrophysics Data System (ADS)
Taylor, J. B.; Newton, S. L.
2015-10-01
> These notes are based on lectures given by one of us (J.B.T.) at the University of Texas in Austin in 1991. Part I concerns some basic features of plasma confinement by magnetic fields as an introduction to an account of plasma relaxation in Part II. Part III discusses confinement by magnetic mirrors, especially minimum- systems. It also includes a general discussion of adiabatic invariants and of the principle of maximal ordering in perturbation theory. Part IV is devoted to the analysis of perturbations in toroidal plasmas and the stability of ballooning modes.
Specialized minimal PDFs for optimized LHC calculations.
Carrazza, Stefano; Forte, Stefano; Kassabov, Zahari; Rojo, Juan
2016-01-01
We present a methodology for the construction of parton distribution functions (PDFs) designed to provide an accurate representation of PDF uncertainties for specific processes or classes of processes with a minimal number of PDF error sets: specialized minimal PDF sets, or SM-PDFs. We construct these SM-PDFs in such a way that sets corresponding to different input processes can be combined without losing information, specifically as regards their correlations, and that they are robust upon smooth variations of the kinematic cuts. The proposed strategy never discards information, so that the SM-PDF sets can be enlarged by the addition of new processes, until the prior PDF set is eventually recovered for a large enough set of processes. We illustrate the method by producing SM-PDFs tailored to Higgs, top-quark pair, and electroweak gauge boson physics, and we determine that, when the PDF4LHC15 combined set is used as the prior, around 11, 4, and 11 Hessian eigenvectors, respectively, are enough to fully describe the corresponding processes.
Plasma Physics Calculations on a Parallel Macintosh Cluster
NASA Astrophysics Data System (ADS)
Decyk, Viktor K.; Dauger, Dean E.; Kokelaar, Pieter R.
We have constructed a parallel cluster consisting of 16 Apple Macintosh G3 computers running the MacOS, and achieved very good performance on numerically intensive, parallel plasma particle-in-cell simulations. A subset of the MPI message-passing library was implemented in Fortran77 and C. This library enabled us to port code, without modification, from other parallel processors to the Macintosh cluster. For large problems where message packets are large and relatively few in number, performance of 50-150 Mflops/node is possible, depending on the problem. This is fast enough that 3D calculations can be routinely done. Unlike Unix-based clusters, no special expertise in operating systems is required to build and run the cluster. Full details are available on our web site: http://exodus.physics.ucla.edu/appleseed/.
Plasma Physics Calculations on a Parallel Macintosh Cluster
NASA Astrophysics Data System (ADS)
Decyk, Viktor; Dauger, Dean; Kokelaar, Pieter
2000-03-01
We have constructed a parallel cluster consisting of 16 Apple Macintosh G3 computers running the MacOS, and achieved very good performance on numerically intensive, parallel plasma particle-in-cell simulations. A subset of the MPI message-passing library was implemented in Fortran77 and C. This library enabled us to port code, without modification, from other parallel processors to the Macintosh cluster. For large problems where message packets are large and relatively few in number, performance of 50-150 MFlops/node is possible, depending on the problem. This is fast enough that 3D calculations can be routinely done. Unlike Unix-based clusters, no special expertise in operating systems is required to build and run the cluster. Full details are available on our web site: http://exodus.physics.ucla.edu/appleseed/.
The calculation of thermophysical properties of nickel plasma
Apfelbaum, E. M.
2015-09-15
The thermophysical properties of Nickel plasma have been calculated for the temperatures 10–60 kK and densities less than 1 g/cm{sup 3}. These properties are the pressure, internal energy, heat capacity, and the electronic transport coefficients (electrical conductivity, thermal conductivity, and thermal power). The thermodynamic values have been calculated by means of the chemical model, which also allows one to obtain the ionic composition of considered plasma. The composition has been used to calculate the electronic transport coefficients within the relaxation time approximation. The results of the present investigation have been compared with the calculations of other researchers and available data of measurements.
Calculation of tin atomic data and plasma properties.
Morozov, V.; Tolkach, V.; Hassanein, A.
2005-08-26
This report reviews the major methods and techniques we use in generating basic atomic and plasma properties relevant to extreme ultraviolet (EUV) lithography applications. The basis of the work is the calculation of the atomic energy levels, transitions probabilities, and other atomic data by various methods, which differ in accuracy, completeness, and complication. Later on, we calculate the populations of atomic levels and ion states in plasmas by means of the collision-radiation equilibrium (CRE) model. The results of the CRE model are used as input to the thermodynamic functions, such as pressure and temperature from the internal energy and density (equation of state), electric resistance, thermal conduction, and other plasma properties. In addition, optical coefficients, such as emission and absorption coefficients, are generated to resolve a radiation transport equation (RTE). The capabilities of our approach are demonstrated by generating the required atomic and plasma properties for tin ions and plasma within the EUV region near 13.5 nm.
Simplified method for calculation of equilibrium plasma composition
NASA Astrophysics Data System (ADS)
Rydalevskaya, Maria A.
2017-06-01
In this work, a simplified method for the evaluation of equilibrium composition of plasmas consisted of monoatomic species is proposed. Multicomponent gas systems resulting from thermal ionization of spatially uniform mixtures are assumed enough rarefied to be treated as ideal gases even after multiple ionization steps. The method developed for the calculation of equilibrium composition of these mixtures makes use of the fundamental principles of statistical physics. Equilibrium concentrations of mixture components are determined by integration of distribution functions over the space of momentum and summation over electronic energy levels. These functions correspond to the entropy maximum. To determine unknown parameters, the systems of equations corresponding to the normalization conditions are derived. It is shown that the systems may be reduced to one algebraic equation if the equilibrium temperature is known. Numeral method to solve this equation is proposed. Special attention is given to the ionized mixtures, generated from the atoms of a single chemical species and the situations, when in the gas only the first- or the first- and second-order ionization are possible.
Calculation of electronic transport coefficients of Ag and Au plasma
Apfelbaum, E. M.
2011-12-15
The thermoelectric transport coefficients of silver and gold plasma have been calculated within the relaxation-time approximation. We considered temperatures of 10-100 kK and densities of {rho} < or approx. 1 g/cm{sup 3}. The plasma composition was calculated using a corresponding system of coupled mass action laws, including the atom ionization up to +4. For momentum cross sections of electron-atom scattering we used the most accurate expressions available. The results of our modeling have been compared with other researchers' data whenever possible.
Special issue on the spectroscopy of transient plasmas
NASA Astrophysics Data System (ADS)
Bailey, James; Hoarty, David; Mancini, Roberto; Yoneda, Hitoki
2015-01-01
Experimental and theoretical papers are invited for a special issue of Journal of Physics B: Atomic, Molecular and Optical Physics on Spectroscopy of Transient Plasmas, covering plasma conditions produced by pulsed laboratory sources including for example, short and long pulse lasers; pulsed power devices; FELs; XFELs and ion beams. The full range of plasma spectroscopy from the optical range up to high energy bremsstrahlung radiation will be covered. The deadline for submitting to this special issue is 1 March 2015. (Expected web publication: autumn 2015). Late submissions will be considered for the journal, but may not be included in the special issue. All submitted articles will be fully refereed to the journal's usual high standards. Upon publication, the issue will be widely promoted to the atomic, molecular and optical physics community, ensuring that your work receives maximum visibility. Articles should be submitted at http://mc04.manuscriptcentral.com/jphysb-iop. Should you have any questions regarding the preparation of manuscripts or the suitability of your work for this Issue, please do not hesitate to contact the J. Phys. B: At. Mol. Opt. Editorial team (jphysb@iop.org). We look forward to hearing from you and hope that we can welcome you as a contributing author.
Representation of the Geosynchronous Plasma Environment in Spacecraft Charging Calculations
NASA Technical Reports Server (NTRS)
Davis, V. A.; Mandell, M. J.; Thomsen, M. F.
2006-01-01
Historically, our ability to predict and postdict spacecraft surface charging has been limited by the characterization of the plasma environment. One difficulty lies in the common practice of fitting the plasma data to a Maxwellian or Double Maxwellian distribution function, which may not represent the data well for charging purposes. We use electron and ion flux spectra measured by the Los Alamos National Laboratory (LANL) Magnetospheric Plasma Analyzer (MPA) to examine how the use of different spectral representations of the charged particle environment in computations of spacecraft potentials during magnetospheric substorms affects the accuracy of the results. We calculate the spacecraft potential using both the measured fluxes and several different fits to these fluxes. These measured fluxes have been corrected for the difference between the measured and calculated potential. The potential computed using the measured fluxes and the best available material properties of graphite carbon, with a secondary electron escape fraction of 81%, is within a factor of three of the measured potential for 87% of the data. Potentials calculated using a Kappa function fit to the incident electron flux distribution function and a Maxwellian function fit to the incident ion flux distribution function agree with measured potentials nearly as well as do potentials calculated using the measured fluxes. Alternative spectral representations gave less accurate estimates of potential. The use of all the components of the net flux, along with spacecraft specific average material properties, gives a better estimate of the spacecraft potential than the high energy flux alone.
Calculation and application of combined diffusion coefficients in thermal plasmas
NASA Astrophysics Data System (ADS)
Murphy, Anthony B.
2014-03-01
The combined diffusion coefficient method is widely used to treat the mixing and demixing of different plasma gases and vapours in thermal plasmas, such as welding arcs and plasma jets. It greatly simplifies the treatment of diffusion for many gas mixtures without sacrificing accuracy. Here, three subjects that are important in the implementation of the combined diffusion coefficient method are considered. First, it is shown that different expressions for the combined diffusion coefficients, arising from different definitions for the stoichiometric coefficients that assign the electrons to the two gases, are equivalent. Second, an approach is presented for calculating certain partial differential terms in the combined temperature and pressure diffusion coefficients that can cause difficulties. Finally, a method for applying the combined diffusion coefficients in computational models, which typically require diffusion to be expressed in terms of mass fraction gradients, is given.
Calculation and application of combined diffusion coefficients in thermal plasmas.
Murphy, Anthony B
2014-03-07
The combined diffusion coefficient method is widely used to treat the mixing and demixing of different plasma gases and vapours in thermal plasmas, such as welding arcs and plasma jets. It greatly simplifies the treatment of diffusion for many gas mixtures without sacrificing accuracy. Here, three subjects that are important in the implementation of the combined diffusion coefficient method are considered. First, it is shown that different expressions for the combined diffusion coefficients, arising from different definitions for the stoichiometric coefficients that assign the electrons to the two gases, are equivalent. Second, an approach is presented for calculating certain partial differential terms in the combined temperature and pressure diffusion coefficients that can cause difficulties. Finally, a method for applying the combined diffusion coefficients in computational models, which typically require diffusion to be expressed in terms of mass fraction gradients, is given.
High-voltage plasma interactions calculations using NASCAP/LEO
NASA Technical Reports Server (NTRS)
Mandell, M. J.; Katz, I.
1990-01-01
This paper reviews four previous simulations (two laboratory and two space-flight) of interactions of a high-voltage spacecraft with a plasma under low-earth orbit conditions, performed using a three-dimensional computer code NASCAP/LEO. Results show that NASCAP/LEO can perform meaningful simulations of high-voltage plasma interactions taking into account three-dimensional effects of geometry, spacecraft motion, and magnetic field. Two new calculations are presented: (1) for current collection by 1-mm pinholes in wires (showing that a pinhole in a wire can collect far more current than a similar pinhole in a flat plate); and (2) current collection by Charge-2 mother vehicle launched in December 1985. It is shown that the Charge-2 calculations predicted successfully ion collection at negative bias, the floating potential of a probe outside or inside the sheath under negative bias conditions, and magnetically limited electron collection under electron beam operation at high altitude.
High-voltage plasma interactions calculations using NASCAP/LEO
NASA Technical Reports Server (NTRS)
Mandell, M. J.; Katz, I.
1990-01-01
This paper reviews four previous simulations (two laboratory and two space-flight) of interactions of a high-voltage spacecraft with a plasma under low-earth orbit conditions, performed using a three-dimensional computer code NASCAP/LEO. Results show that NASCAP/LEO can perform meaningful simulations of high-voltage plasma interactions taking into account three-dimensional effects of geometry, spacecraft motion, and magnetic field. Two new calculations are presented: (1) for current collection by 1-mm pinholes in wires (showing that a pinhole in a wire can collect far more current than a similar pinhole in a flat plate); and (2) current collection by Charge-2 mother vehicle launched in December 1985. It is shown that the Charge-2 calculations predicted successfully ion collection at negative bias, the floating potential of a probe outside or inside the sheath under negative bias conditions, and magnetically limited electron collection under electron beam operation at high altitude.
Efficient calculation of atomic rate coefficients in dense plasmas
NASA Astrophysics Data System (ADS)
Aslanyan, Valentin; Tallents, Greg J.
2017-03-01
Modelling electron statistics in a cold, dense plasma by the Fermi-Dirac distribution leads to complications in the calculations of atomic rate coefficients. The Pauli exclusion principle slows down the rate of collisions as electrons must find unoccupied quantum states and adds a further computational cost. Methods to calculate these coefficients by direct numerical integration with a high degree of parallelism are presented. This degree of optimization allows the effects of degeneracy to be incorporated into a time-dependent collisional-radiative model. Example results from such a model are presented.
The calculations of thermophysical properties of molybdenum plasma
NASA Astrophysics Data System (ADS)
Apfelbaum, E. M.
2017-05-01
The thermophysical properties (pressure, internal energy, conductivity, thermal conductivity, and thermal power) of molybdenum plasma at temperatures 10-60 kK and densities less than 2 g/cm3 have been calculated. The corresponding model has been developed on the basis of the chemical approach and relaxation time approximation. The approximations used in our model are valid under these conditions. A comparison with available experimental data on conductivity has shown good agreement in this area.
Numerical calculation of charge exchange cross sections for plasma diagnostics
NASA Astrophysics Data System (ADS)
Mendez, Luis
2016-09-01
The diagnostics of impurity density and temperature in the plasma core in tokamak plasmas is carried out by applying the charge exchange recombination spectroscopy (CXRS) technique, where a fast beam of H atoms collides with the plasma particles leading to electron capture reactions with the impurity ions. The diagnostics is based on the emission of the excited ions formed in the electron capture. The application of the CXRS requires the knowledge of accurate state-selective cross sections, which in general are not accessible experimentally, and the calculation of cross sections for the high n capture levels, required for the diagnostics in the intermediate energy domain of the probe beam, is particularly difficult. In this work, we present a lattice numerical method to solve the time dependent Schrödinger equation. The method is based on the GridTDSE package, it is applicable in the wide energy range 1 - 500 keV/u and can be used to assess the accuracy of previous calculations. The application of the method will be illustrated with calculations for collisions of multiply charged ions with H. Work partially supported by project ENE2014-52432-R (Secretaria de Estado de I+D+i, Spain).
Representation of the Geosynchronous Plasma Environment for Spacecraft Charging Calculations
NASA Technical Reports Server (NTRS)
Davis, V. A.; Mandell, M. J.; Thomsen, M. F.
2004-01-01
Historically, our ability to predict and postdict surface charging has suffered from both a lack of reliable secondary emission and backscattered electron yields and poor characterization of the plasma environment. One difficulty lies in the common practice of fitting the plasma data to a Maxwellian or Double Maxwellian distribution function, which may not represent the data well for charging purposes. For 13 years Los Alamos National Laboratory (LANL) has been accumulating measurements of electron and proton spectra from Magnetospheric Plasma Analyzer (MPA) instruments aboard a series of geosynchronous satellites. These data provide both a plasma characterization and the potential of the instrument ground. We use electron and ion flux spectra measured by the LANL MPA to examine how the use of different spectral representations of the charged particle environment in computations of spacecraft potentials during magnetospheric substorms affects the accuracy of the results. We calculate the spacecraft potential using both the measured fluxes and several different fits to these fluxes. These flux measurements and fits have been corrected for the difference between the measured and calculated potential. The potentials computed using the measured fluxes, the best available material properties of graphite carbon, and a secondary electron escape fraction of 81%, are within a factor of three of the measured potential for nearly all the data. Using a Kappa fit to the electron distribution function and a Maxwellian fit to the ion distribution function gives agreement similar to the calculations using the actual data. Alternative spectral representations, including Maxwellian and double Maxwellian for both species, lead to less satisfactory agreement between predicted and measured potentials.
Representation of the Geosynchronous Plasma Environment for Spacecraft Charging Calculations
NASA Astrophysics Data System (ADS)
Davis, V. A.; Mandell, M. J.; Thomsen, M. F.
2002-12-01
We are using the Los Alamos National Laboratory (LANL) Magnetospheric Plasma Analyzer (MPA) dataset to determine the best spectral representation of the charged particle environment for calculating spacecraft potential during magnetospheric substorms. For 12 years LANL has been accumulating measurements of electron and proton spectra from MPA instruments aboard a series of geosynchronous satellites. These data provide both a plasma characterization and the potential of the instrument ground. Here we focus on data during eclipse periods in Sept. 2001, containing 970 measurements of charging to potentials ranging from 3 V to nearly 10 kV. Our ability to predict and "postdict" charging has suffered from both a lack of reliable secondary emission and backscattered electron yields and poor characterization of the plasma environment. One difficulty lies in the common practice of fitting the plasma data to a Maxwellian or Double Maxwellian distribution function, which may not represent the data well for charging purposes. The net current to the spacecraft is the sum of the incident electron and ion fluxes, secondary and backscattered electron fluxes, and photoelectron flux. The integral of the incident spectrum against the yield functions gives the secondary and backscattered fluxes. At equilibrium, the net current is zero. We calculate the spacecraft potential using the measured fluxes, either directly or through a fit, with appropriate correction for the difference between the measured and postulated potential. The ratio of the calculated to the measured potential tests the accuracy of the net flux calculation. The potential computed using the measured fluxes and the best available material properties of graphite carbon, with a secondary electron escape fraction of 81%, is within a factor of three of the measured potential for nearly all the data. Using a Kappa function fit to the electron distribution and a Maxwellian function fit to the ion distribution gives similar
Radio Frequency Field Calculations for Plasma Heating Simulations in VASIMR
NASA Astrophysics Data System (ADS)
Ilin, A. V.; Díaz, F. R. Chang; Squire, J. P.; Carter, M. D.
2002-01-01
(VASIMR)1 is plasma heating by ion-cyclotron RF heating (ICRF). Mathematical simulation helps to design an ICRF antenna, i.e. make maximal absorption of RF power into the plasma in the resonance area. Another goal of a particle simulation is design of a magnetic nozzle and optimize the performance of VASIMR2. field in the plasma, 2) ion density and velocity, 3) ion-cyclotron radio-frequency electromagnetic field. The assumptions of quasineutral and collisionless plasma are based on the range of operating VASIMR parameters. Carlo simulations for systems of million of particles in a reasonable time and without the need for a powerful supercomputer. The particle to grid weighting method is used for calculating the ion density, which is used for recalculation of the electric potential and RF field. dimensional problem to a weighted sum over two-dimensional solutions. Absorption is introduced in the cold plasma model by adding an imaginary collision frequency to the RF driven frequency, which is equivalent to adding an imaginary particle mass in the dielectric tensor elements. static and RF fields using the VASIMR code2. The VASIMR and EMIR codes are then iterated to estimate the ICRF effects on the plasma density. The iteration is performed by calculating the RF fields with the EMIR code, and using these fields to follow nonlinear ion trajectories with the VASIMR code on the gyro-frequency time scale. The ion trajectories are used to generate RF power absorption values and a density input for the next EMIR calculation. The codes are iterated until the density profile becomes reasonably stable, then the collisional absorption parameter in the EMIR code is adjusted and the iteration is continued until the power deposited by the RF system matches the power absorbed by the ion trajectories in a global sense. electric field. The solved algebraic system of equations is represented by ill-conditioned 18-diagonal matrix with complex elements. Since early development of the
Calculation of atomic structures and radiative properties of fusion plasmas
NASA Astrophysics Data System (ADS)
Jarrah, Walid; Pain, Jean-Christophe; Benredjem, Djamel
2017-03-01
The opacity is an important issue in the knowledge of the radiative properties of Inertial Confinement Fusion (ICF) and astrophysical plasmas. In this work we present the opacity of the mixture C+Si, composing the ablator of some ICF capsules. We have used Cowan's code to calculate the atomic structure of carbon and silicon. We also have developed a collisional-radiative model in order to obtain the opacity of the mixture. Line broadening, line shift and ionization potential depression are taken into account in the opacity profile. Comparisons to other calculations are carried out. NLTE and LTE opacity calculations show discrepancies mainly in the range 1900-2000 eV for the bound-bound contribution to the total opacity and in the range 50-350 eV for the bound-free contribution. We have also accounted for photoexcitation and photoionization processes. The corresponding rates are obtained by modeling the Hohlraum radiation by a Planckian distribution at a radiative temperature of 300 eV.
40 CFR 75.75 - Additional ozone season calculation procedures for special circumstances.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 17 2014-07-01 2014-07-01 false Additional ozone season calculation... § 75.75 Additional ozone season calculation procedures for special circumstances. (a) The owner or operator of a unit that is required to calculate ozone season heat input for purposes of providing...
40 CFR 75.75 - Additional ozone season calculation procedures for special circumstances.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 17 2012-07-01 2012-07-01 false Additional ozone season calculation... § 75.75 Additional ozone season calculation procedures for special circumstances. (a) The owner or operator of a unit that is required to calculate ozone season heat input for purposes of providing...
40 CFR 75.75 - Additional ozone season calculation procedures for special circumstances.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 16 2011-07-01 2011-07-01 false Additional ozone season calculation... § 75.75 Additional ozone season calculation procedures for special circumstances. (a) The owner or operator of a unit that is required to calculate ozone season heat input for purposes of providing...
40 CFR 75.75 - Additional ozone season calculation procedures for special circumstances.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Additional ozone season calculation... § 75.75 Additional ozone season calculation procedures for special circumstances. (a) The owner or operator of a unit that is required to calculate ozone season heat input for purposes of providing...
40 CFR 75.75 - Additional ozone season calculation procedures for special circumstances.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 17 2013-07-01 2013-07-01 false Additional ozone season calculation... § 75.75 Additional ozone season calculation procedures for special circumstances. (a) The owner or operator of a unit that is required to calculate ozone season heat input for purposes of providing...
Equilibrium calculations for plasma control in CIT (Compact Ignition Tokamak)
Strickler, D.J.; Peng, Y-K.M. . Fusion Engineering Design Center); Pomphrey, N.; Jardin, S.C. . Plasma Physics Lab.)
1990-01-01
The free-boundary equilibrium code VEQ provides equilibrium data that are used by the Tokamak Simulation Code (TSC) in design and analysis of the poloidal field (PF) system for the Compact Ignition Tokamak (CIT). VEQ serves as an important design tool for locating the PF coils and defining coil current trajectories and control systems for TSC. In this report, VEQ and its role in the TSC analysis of the CIT PF system are described. Equilibrium and coil current calculations are discussed, an overview of the CIT PF system is presented, a set of reference equilibria for modeling a complete discharge in CIT is described, and the concept of a plasma shape control matrix is introduced. 9 refs., 8 figs., 7 tabs.
Calculation of Threshold Conditions for Materials Charging in Maxwellian Plasmas.
2014-09-26
Conditions for Materials Charging in Maxwellian Plasmas 1. BACKGROUND DeForest I found that the ATS-5 spacecraft, in geosynchronous orbit, charged up...kilovolts in sunlight. DeForest showed that the theory of the Langmuir probe in a plasma provides an explanation of the observed surface potentials. In...contrast to labora- tory plasma, geosynchronous orbit plasmas have temperatures of many kilovolts. DeForest found that the secondary electron emission
Preface to Special Topic: Plasmas for Medical Applications
NASA Astrophysics Data System (ADS)
Keidar, Michael; Robert, Eric
2015-12-01
Intense research effort over last few decades in low-temperature (or cold) atmospheric plasma application in bioengineering led to the foundation of a new scientific field, plasma medicine. Cold atmospheric plasmas (CAP) produce various chemically reactive species including reactive oxygen species (ROS) and reactive nitrogen species (RNS). It has been found that these reactive species play an important role in the interaction of CAP with prokaryotic and eukaryotic cells triggering various signaling pathways in cells.
Preface to Special Topic: Plasmas for Medical Applications
Keidar, Michael; Robert, Eric
2015-12-15
Intense research effort over last few decades in low-temperature (or cold) atmospheric plasma application in bioengineering led to the foundation of a new scientific field, plasma medicine. Cold atmospheric plasmas (CAP) produce various chemically reactive species including reactive oxygen species (ROS) and reactive nitrogen species (RNS). It has been found that these reactive species play an important role in the interaction of CAP with prokaryotic and eukaryotic cells triggering various signaling pathways in cells.
ERIC Educational Resources Information Center
Rumiati, Rumi; Wright, Robert J.
2014-01-01
Pat was a 19-year-old attending a Special School for the Intellectually Disabled in Indonesia. She was interviewed by the first author regarding her mental calculation strategies when solving 1- and 2-digit addition and subtraction problems. Results indicate that she was able to see ten as a unit composed of ten ones and was facile in using…
Infrared Radiometery and Heat Flux Calculation for a Helicon Plasma
NASA Astrophysics Data System (ADS)
Berisford, Daniel; Lee, Charles A.; Raja, L. L.; Bengtson, Roger D.
2006-10-01
Using an infrared camera, we measured the external temperature of a quartz tube containing a 1 kW helicon Argon plasma. An Inframetrics model 600 IR camera connected to a computer DAQ system records the temperature evolution of the quartz tube surface in the vicinity of the antenna during and after the pulse. Using these measurements, we estimated the heat flux profile from the plasma into the quartz tube walls. A MATLAB code uses pre- and post- pulse snapshot images from the video to estimate the heat flux into the quartz from the plasma. Initial results have shown a broad heating profile with localized power input into the quartz under the helical antenna. We find approximately 30% of the total RF power deposited into the tube as heat, and heating directly under the antenna accounts for about 30% of this heat input.
Variational calculations for resonance oscillations of inhomogeneous plasmas
NASA Technical Reports Server (NTRS)
Peng, Y. K. M.; Crawford, F. W.
1973-01-01
The electrostatic resonance properties of an inhomogeneous plasma column are reported by application of the Rayleigh-Ritz method. A description of the rf equation of motion and pressure term that expresses the system of equations in Euler-Lagrange form is presented. The Rayleigh-Ritz procedure is applied to the corresponding Lagrangian to obtain approximate resonance frequencies and eigenfunctions. An appropriate set of trial coordinate functions is defined, which leads to frequency and eigenfunction estimates.
Atomic physics calculations in support of studies for high energy density plasmas
Wang, P.; MacFarlane, J.J.; Moses, G.A.; Mehlhorn, T.A.
1995-12-31
The studies of high energy density plasmas require basic atomic data, equations of state, opacities, and stopping power. Unfortunately, the related experimental data are very limited. To obtain these data for a wide domain of plasma conditions, one must rely on theoretical calculations. The authors have developed an atomic physics calculation package which can provide high quality atomic data for numerical simulations of high energy density plasmas. In this paper, they give detailed descriptions of physics models used in the package. Particular emphasis will be on a hybrid model for equations of state, a self-consistent field model for ion stopping power, and opacity calculations.
Plasma confinement calculations for TIBER-II: Final report
Ibrahim, E.
1987-10-14
This paper compares the empirically based TIBER II design parameters against the reactor parameters of a tokamak based on a theoretical model of heat transport. The motivation behind this project is the following. The present TIBER-II design is based on an empirical scaling of confinement time tau/sub E/ known as Kaye-Goldston scaling. This empirical scaling is based on data from tokamak plasmas whose temperatures did not exceed a few keV, while the TIBER-II requires electron temperatures of 25 keV. The question, then, is whether the Kaye Goldston scaling is valid at temperatures above the range of empirical data. For this we must turn to theory. If a theoretical transport model is available that shows favorable correlation with the Kaye-Goldston scaling in the range of a few keV, then this scaling could be extrapolated to the 25 keV range required for TIBER-II. The project is divided into two parts. Part one of the project concerns the development of a transport model from plasma theory that has empirical support. Part two of the project consists of applying the transport model to the TIBER-II design. 8 refs., 3 tabs.
Analytic calculation of physiological acid-base parameters in plasma.
Wooten, E W
1999-01-01
Analytic expressions for plasma total titratable base, base excess (DeltaCB), strong-ion difference, change in strong-ion difference (DeltaSID), change in Van Slyke standard bicarbonate (DeltaVSSB), anion gap, and change in anion gap are derived as a function of pH, total buffer ion concentration, and conditional molar equilibrium constants. The behavior of these various parameters under respiratory and metabolic acid-base disturbances for constant and variable buffer ion concentrations is considered. For constant noncarbonate buffer concentrations, DeltaSID = DeltaCB = DeltaVSSB, whereas these equalities no longer hold under changes in noncarbonate buffer concentration. The equivalence is restored if the reference state is changed to include the new buffer concentrations.
Plasma-equilibrium calculations by line successive over relaxation
Redi, M.H.; Larrabee, D.A.
1983-05-01
Line successive over relaxation (LSOR) is an iterative method for solving elliptic differential equations. LSOR takes advantage of the CRAY vector capabilities as compared to the point successive over relaxation (SOR) method, which does not vectorize. The substantial advantages of LSOR on a vectorizing machine are not well-known, except in the field of aerodynamics. By minor modification of the traditional SOR elliptic equation solver, we find that in certain coordinates an increase of a factor of two or greater in convergence time can be realized. As a model problem for comparison of SOR and LSOR, the numerical solution of Poisson's equation will be reviewed in Sec. II. In Sec. III, we discuss the decreased computation time on the National Fusion Energy Computer Center (NMFECC) CRAY computers found with LSOR applied to the iterative solution of plasma equilibria. In Sec. IV, the conditions for which LSOR is most useful are summarized.
An Exact Calculation of Electron-Ion Energy Splitting in a Hot Plasma
Singleton, Robert L
2012-09-10
In this brief report, I summarize the rather involved recent work of Brown, Preston, and Singleton (BPS). In Refs. [2] and [3], BPS calculate the energy partition into ions and electrons as a charged particle traverses a non-equilibrium two-temperature plasma. These results are exact to leading and next-to-leading order in the plasma coupling g, and are therefore extremely accurate in a weakly coupled plasma. The new BPS calculations are compared with the more standard work of Fraley et al. [12]. The results differ substantially at higher temperature when T{sub I} {ne} T{sub e}.
NASA Astrophysics Data System (ADS)
Howling, A. A.; Guittienne, Ph; Jacquier, R.; Furno, I.
2015-12-01
The coupling between an inductive source and the plasma determines the power transfer efficiency and the reflected impedance in the primary circuit. Usually, the plasma coupling is analysed by means of a transformer equivalent circuit, where the plasma inductance and resistance are estimated using a global plasma model. This paper shows that, for planar RF antennas, the mutual inductance between the plasma and the primary circuit can be calculated using partial inductances and the complex image method, where the plasma coupling is determined in terms of the plasma skin depth and the distance to the plasma. To introduce the basic concepts, the mutual inductance is calculated here for a linear conductor parallel to the plasma surface. In the accompanying paper part II Guittienne et al (2015 Plasma Sources Sci. Technol. 24 065015), impedance measurements on a RF resonant planar plasma source are modeled using an impedance matrix where the plasma-antenna mutual impedances are calculated using the complex image method presented here.
Comparison of Calculated Plasma Mode Frequencies with Experiment
NASA Astrophysics Data System (ADS)
Tobler, Samuel; Peterson, Bryan G.; Hart, Grant W.
2004-11-01
We have measured the diocotron and Trivelpiece-Gould mode frequencies, radial density profile and central temperature in a long (0.6 m), cylindrical Malmberg-Penning electron trap at four different magnetic field strengths. The total particle count varied by a factor of 10 and the magnetic field varied by a factor of 3.5. The temperatures were fairly constant. Using an equilibrium code (EQUILSOR), a 2-D particle-in-cell code (RATTLE), and a 3-D particle-in-cell code (INFERNO) we have calculated the frequencies corresponding to the experimental conditions. We will discuss the limitations of the codes and the conditions in which they agree with experimental results.
Comparison of Non-Neutral Plasma Normal Modes with Calculation
NASA Astrophysics Data System (ADS)
Tobler, Samuel K.; Peterson, Bryan G.; Hart, Grant W.; Spencer, Ross L.
2004-10-01
We have measured the diocotron and Trivelpiece-Gould mode frequencies, radial density profile and central temperature in a long (0.6 m), cylindrical Malmberg-Penning electron trap at four different magnetic field strengths. The total particle count varied by a factor of 10 and the magnetic field varied by a factor of 3.5. The temperatures were fairly constant. Using an equilibrium code (EQUILSOR), a 2-D particle-in-cell code (RATTLE), and a 3-D particle-in-cell code (INFERNO) we have calculated the frequencies corresponding to the experimental conditions. We will discuss the limitations of the codes and the conditions in which they agree with experimental results.
NASA Astrophysics Data System (ADS)
de Jong, Maarten; Qi, Liang; Olmsted, David L.; van de Walle, Axel; Asta, Mark
2016-03-01
A method is described for calculating the energetics of planar defects in alloys based on the special-quasirandom-structure (SQS) approach. We examine the accuracy of the approach employing atomistic calculations based on a classical embedded-atom-method (EAM) interatomic potential for hexagonal close packed (hcp) alloys, for which benchmark results can be obtained by direct configurational averaging. The results of these calculations demonstrate that the SQS-based approach can be employed to derive the concentration dependence of the energies of twin boundaries, unstable stacking faults, and surfaces to within an accuracy of approximately 10%. The SQS considered in this study contain up to 72 atoms and hence are small enough to be considered in first-principles density-functional-theory (DFT) based calculations. The application of the SQS-based approach in direct DFT-based calculations is demonstrated in a study of the concentration dependence of interfacial energies for {11 2 ¯1 } twins in hcp Ti-Al alloys.
Li, W. P.; Liu, Y.; Long, Q.; Chen, D. H.; Chen, Y. M.
2008-10-15
The electromagnetic field (both E and B fields) is calculated for a solenoidal inductively coupled plasma (ICP) discharge. The model is based on two-dimensional cylindrical coordinates, and the finite difference method is used for solving Maxwell equations in both the radial and axial directions. Through one-turn coil measurements, assuming that the electrical conductivity has a constant value in each cross section of the discharge tube, the calculated E and B fields rise sharply near the tube wall. The nonuniform radial distributions imply that the skin effect plays a significant role in the energy balance of the stable ICP. Damped distributions in the axial direction show that the magnetic flux gradually dissipates into the surrounding space. A finite difference calculation allows prediction of the electrical conductivity and plasma permeability, and the induction coil voltage and plasma current can be calculated, which are verified for correctness.
High resolution equilibrium calculations of pedestal and SOL plasma in tokamaks
NASA Astrophysics Data System (ADS)
Medvedev, S. Yu; Martynov, A. A.; Drozdov, V. V.; Ivanov, A. A.; Poshekhonov, Yu Yu
2017-02-01
For integrated modeling of equilibrium, stability and dynamics of the divertor tokamak plasma with scrape-off layer (SOL) high resolution equilibrium calculations are needed. A new version of the CAXE equilibrium code computes the tokamak equilibrium on a numerical grid adaptive to magnetic surfaces both in the plasma region with closed flux surfaces and in the SOL region with open magnetic lines. The plasma profiles can be prescribed independently in each region with nested flux surfaces, and realistic SOL profiles with very short pressure drop off length can be accurately treated. The influence of the finite current density in SOL on the connection length is studied. From the point of view of the MHD equilibrium and stability modeling, self-consistent calculations of diverted tokamak configurations with finite current density at the separatrix require taking into account plasma outside the separatrix. Calculated high resolution equilibria provide an input to new versions of the ideal MHD stability codes treating tokamak plasma with SOL. The study of the influence of the pressure gradient profile in the pedestal plasma inside and outside the separatrix on the pedestal height limit set by external kink-ballooning mode stability is presented. Another possible application of the high resolution pedestal and SOL equilibrium code is a coupling to the SOLPS code with a purpose to increase equilibrium accuracy and support self-consistent plasma flow/equilibrium modeling.
NASA Technical Reports Server (NTRS)
Anderson, D. N.; Heelis, R. A.; Mcclure, J. P.
1987-01-01
After calculating ambient electron densities as a function of altitude, latitude and local time, a simplified expression is used to calculate F-region eastward plasma drifts given a zonal neutral wind model. The derived eastward plasma drift on a magnetic flux tube is examined as a function of the flux tube apex height. If the neutral wind is assumed to be independent of latitude the plasma drift maximizes along the flux tube which intercepts the F-region peak concentration at the Appleton anomaly. Above this altitude the velocity decreases to reflect a decrease in the flux tube integrated F-region Pedersen conductivity. For a latitude dependent wind the plasma drift tends to maximize along the flux tube which intercepts the F-peak at the dip equator. Above this altitude the drift decreases to reflect the latitude distribution of the wind.
Programmable calculator software for computation of the plasma binding of ligands.
Conner, D P; Rocci, M L; Larijani, G E
1986-01-01
The computation of the extent of plasma binding of a ligand to plasma constituents using radiolabeled ligand and equilibrium dialysis is complex and tedious. A computer program for the HP-41C Handheld Computer Series (Hewlett-Packard) was developed to perform these calculations. The first segment of the program constructs a standard curve for quench correction of post-dialysis plasma and buffer samples, using either external standard ratio (ESR) or sample channels ratio (SCR) techniques. The remainder of the program uses the counts per minute, SCR or ESR, and post-dialysis volume of paired plasma and buffer samples generated from the dialysis procedure to compute the extent of binding after correction for background radiation, counting efficiency, and intradialytic shifts of fluid between plasma and buffer compartments during dialysis. This program greatly simplifies the analysis of equilibrium dialysis data and has been employed in the analysis of dexamethasone binding in normal and uremic sera.
Nonrelativistic structure calculations of two-electron ions in a strongly coupled plasma environment
Bhattacharyya, S.; Saha, J. K.; Mukherjee, T. K.
2015-04-01
In this work, the controversy between the interpretations of recent measurements on dense aluminum plasma created with the Linac coherent light source (LCLS) x-ray free electron laser (FEL) and the Orion laser has been addressed. In both kinds of experiments, heliumlike and hydrogenlike spectral lines are used for plasma diagnostics. However, there exist no precise theoretical calculations for He-like ions within a dense plasma environment. The strong need for an accurate theoretical estimate for spectral properties of He-like ions in a strongly coupled plasma environment leads us to perform ab initio calculations in the framework of the Rayleigh-Ritz variation principle in Hylleraas coordinates where an ion-sphere potential is used. An approach to resolve the long-drawn problem of numerical instability for evaluating two-electron integrals with an extended basis inside a finite domain is presented here. The present values of electron densities corresponding to the disappearance of different spectral lines obtained within the framework of an ion-sphere potential show excellent agreement with Orion laser experiments in Al plasma and with recent theories. Moreover, this method is extended to predict the critical plasma densities at which the spectral lines of H-like and He-like carbon and argon ions disappear. Incidental degeneracy and level-crossing phenomena are being reported for two-electron ions embedded in strongly coupled plasma. Thermodynamic pressure experienced by the ions in their respective ground states inside the ion spheres is also reported.
NASA Astrophysics Data System (ADS)
Lockard, T. E.; Mayes, D. C.; Durmaz, T.; Mancini, R. C.; Loisel, G.; Bailey, J. E.; Rochau, G. A.; Liedahl, D. A.; Heeter, R. F.
2013-10-01
Creating a photoionized plasma in a controlled laboratory environment is difficult due to the intense x-ray flux needed to drive the plasma. This is overcome by the intense flux of x-ray photons produced by the pulsed power Z-machine at Sandia National Laboratories. We discuss improvements to a gascell experiment at Z including new ultrathin windows and window plates, and lower filling pressures that permit producing photoionized plasmas of larger ionization parameters. To understand the radiation environment, constrained view-factor calculations have been performed to model the x-ray flux at the gascell. Radiation-hydrodynamic simulations were also done to provide information on the overall evolution of the plasma and, in particular, the radiation heating of the plasma including non-equilibrium effects. We will also discuss a series of collisional-radiative atomic kinetics calculations that were done using a collection of laboratory and astrophysics codes. These results are useful to understand the relative importance of photon- and particle-driven atomic processes in the plasma. This work is sponsored in part by the National Nuclear Security Administration under the High Energy Density Laboratory Plasmas grant program through DOE Grant DE-FG52-09NA29551, and the Z Facility Fundamental Science Program of SNL.
CHEMEOS: a new chemical-picture-based model for plasma equation-of-state calculations
Hakel, P.; Kilcrease, D. P.
2004-01-01
We present the results of a new plasma equation-of-state (EOS) model currently under development at the Atomic and Optical Theory Group (T-4) in Los Alamos. This model is based on the chemical picture of the plasma and uses the free-energy-minimization technique and the occupation-probability formalism. The model is constructed as a combination of ideal and non-ideal contributions to the total Helmholtz free energy of the plasma including the effects of plasma microfields, strong coupling, and the hard-sphere description of the finite sizes of atomic species with bound electrons. These types of models have been recognized as a convenient and computationally inexpensive tool for modeling of local-thermal-equilibrium (LIE) plasmas for a broad range of temperatures and densities. We calculate the thermodynamic characteristics of the plasma (such as pressure and internal energy), and populations and occupation probabilities of atomic bound states. In addition to a smooth truncation of partition functions necessary for extracting ion populations from the system of Saha-type equations, the occupation probabilities can also be used for the merging of Rydberg line series into their associated bound-free edges. In the low-density, high-temperature regimes the plasma effects are adequately described by the Debye-Huckel model and its corresponding contribution to the total Helmholtz free energy of the plasma. In strongly-coupled plasmas, however, the Debye-Huckel approximation is no longer appropriate. In order to extend the validity of our EOS model to strongly-coupled plasmas while maintaining the analytic nature of our model, we adopt fits to the plasma free energy based on hypernetted-chain and Monte Carlo simulations. Our results for hydrogen are compared to other theoretical models. Hydrogen has been selected as a test-case on which improvements in EOS physics are benchmarked before analogous upgrades are included for any element in the EOS part of the new Los Alamos
Quantum-Mechanical Calculation of Ionization-Potential Lowering in Dense Plasmas
NASA Astrophysics Data System (ADS)
Son, Sang-Kil; Thiele, Robert; Jurek, Zoltan; Ziaja, Beata; Santra, Robin
2014-07-01
The charged environment within a dense plasma leads to the phenomenon of ionization-potential depression (IPD) for ions embedded in the plasma. Accurate predictions of the IPD effect are of crucial importance for modeling atomic processes occurring within dense plasmas. Several theoretical models have been developed to describe the IPD effect, with frequently discrepant predictions. Only recently, first experiments on IPD in Al plasma have been performed with an x-ray free-electron laser, where their results were found to be in disagreement with the widely used IPD model by Stewart and Pyatt. Another experiment on Al, at the Orion laser, showed disagreement with the model by Ecker and Kröll. This controversy shows a strong need for a rigorous and consistent theoretical approach to calculate the IPD effect. Here, we propose such an approach: a two-step Hartree-Fock-Slater model. With this parameter-free model, we can accurately and efficiently describe the experimental Al data and validate the accuracy of standard IPD models. Our model can be a useful tool for calculating atomic properties within dense plasmas with wide-ranging applications to studies on warm dense matter, shock experiments, planetary science, inertial confinement fusion, and nonequilibrium plasmas created with x-ray free-electron lasers.
NASA Astrophysics Data System (ADS)
Ni, Qionglin; Fan, Tieshuan; Zhang, Xing; Zhang, Cheng; Ren, Qilong; Hu, Chundong
2010-12-01
A predictive calculation is carried out for neutral beam heating of fusion plasmas in EAST by using NUBEAM code under certain plasma conditions. Results calculated are analyzed for different plasma parameters. Relations between major plasma parameters, such as density and temperature, are obtained and key physical processes in the neutral beam heating, including beam power deposition, trapped fraction, heating efficiency, and power loss, are simulated. Other physical processes, such as current-drive, toroidal rotation and neutron emission, are also discussed.
NASA Astrophysics Data System (ADS)
Kawamura, T.; Ono, T.; Yamamura, Y.
1995-04-01
Physical sputtering yields from the carbon surface irradiated by the boundary plasma are obtained with the use of the Monte Carlo simulation code ACAT. The yields are calculated for many random initial energy and angle values of incident protons or deuterons with a Maxwellian velocity distribution, and then averaged. Here the temperature of the boundary plasma, the sheath potential and the angle δ between the magnetic field line and the surface normal are taken into account. A new fitting formula for an arrangement of the numerical data of sputtering yield is introduced, in which six fitting parameters are determined from the numerical results and listed. These results provide a way to estimate the erosion of carbon materials irradiated by the boundary plasma. The particle reflection coefficients for deuterons and their neutrals from a carbon surface are also calculated by the same code and presented together with, for comparison, that for the case of monoenergetic normal incidence.
A calculational approach to electron impact excitation of ions in hot solar plasmas
NASA Technical Reports Server (NTRS)
Temkin, A.
1974-01-01
The cross section requirements are presented for studying UV and X-ray emission spectra associated with active and flare-produced plasmas in the sun's corona. The general approach to the calculation of the distorted wave approximation problem is also given.
High density plasma calculation of J-PARC RF negative ion source
NASA Astrophysics Data System (ADS)
Shibata, T.; Asano, H.; Ikegami, K.; Naito, F.; Nanmo, K.; Oguri, H.; Ohkoshi, K.; Shinto, K.; Takagi, A.; Ueno, A.
2017-08-01
Ignition and steady state phases of Radio Frequency (RF) plasma in J-PARC ion source has been investigated by numerical modeling. The model takes into account the transport of plasma particles (electrons, protons, hydrogen molecular ions and cesium ions) in electromagnetic (EM) field with collision processes. Inductively coupled and capacitive EM fields are simultaneously solved in the model with plasma transport. Applying KEK parallel computation system A (64 cores, 56 nodes with 256 GB memory per node), behavior of high density plasma up to 1019 - 1020 m-3 in the steady state is calculated. In the simulation, it has been clarified that inductively coupled electric field in azimuthal direction and magnetic field in axial direction play a key role to maintain high density plasma which oscillates with frequency up to doubled value of applied RF frequency. The spatial distribution plot of plasma density and EM field at each phase may lead to understandings on how RF plasma is kept stable inside the source chamber.
Gyrokinetic Calculations of the Neoclassical Radial Electric Field in Stellarator Plasmas
Lewandowski, J.L.V.; Williams, J.; Boozer, A.H.; Lin, Z.
2001-04-09
A novel method to calculate the neoclassical radial electric field in stellarator plasmas is described. The method, which does not have the inconvenience of large statistical fluctuations (noise) of standard Monte Carlo technique, is based on the variation of the combined parallel and perpendicular pressures on a magnetic surface. Using a three-dimensional gyrokinetic delta f code, the calculation of the radial electric field in the National Compact Stellarator Experiment has been carried out. It is shown that a direct evaluation of radial electric field based on a direct calculation of the radial particle flux is not tractable due to the considerable noise.
NASA Astrophysics Data System (ADS)
Evstatiev, Evstati; Svidzinski, Vladimir; Spencer, Andy; Galkin, Sergei
2014-10-01
Full wave 3-D modeling of RF fields in hot magnetized nonuniform plasma requires calculation of nonlocal conductivity kernel describing the dielectric response of such plasma to the RF field. In many cases, the conductivity kernel is a localized function near the test point which significantly simplifies numerical solution of the full wave 3-D problem. Preliminary results of feasibility analysis of numerical calculation of the conductivity kernel in a 3-D hot nonuniform magnetized plasma in the electron cyclotron frequency range will be reported. This case is relevant to modeling of ECRH in ITER. The kernel is calculated by integrating the linearized Vlasov equation along the unperturbed particle's orbits. Particle's orbits in the nonuniform equilibrium magnetic field are calculated numerically by one of the Runge-Kutta methods. RF electric field is interpolated on a specified grid on which the conductivity kernel is discretized. The resulting integrals in the particle's initial velocity and time are then calculated numerically. Different optimization approaches of the integration are tested in this feasibility analysis. Work is supported by the U.S. DOE SBIR program.
Calculation of the surface tension of liquid metals using a one-component-plasma reference system
NASA Technical Reports Server (NTRS)
Zeng, X. C.; Stroud, D.
1987-01-01
The one-component-plasma (OCP) model is used as a reference system instead of the traditional hard-sphere fluid to calculate the liquid-vapor interfacial surface tension of liquid metals within the density functional formalism. The calculated surface tensions of the alkali metals are in excellent agreement with experiment. For the polyvalent metal Al, the result obtained is larger than experimental measurements. It is concluded that the OCP system is not suitable to describe the liquid-vapor phase transition in simple metals which have a nominal plasma parameter larger than the usual freezing value of about 178. The calculated interfacial widths in all cases are narrower than the expected experimental values.
Proper Orthogonal Decomposition methods for particle-based transport calculations in plasmas
NASA Astrophysics Data System (ADS)
Del-Castillo-Negrete, Diego; Spong, D.; Hirshman, S.
2009-05-01
The Proper Orthogonal Decomposition (POD) is a powerful technique to analyze large data sets by projecting the data into an optimal set of low-order modes that capture the main features of the data. POD methods have been widely used in image and signal processing and also in the study of coherent structures in neutral fluids. However, the use of these techniques in plasma physics is a relatively new area of research. Here we discuss recent novel applications of POD methods to particle-based transport calculations in plasmas. We show that POD techniques provide an efficient method to filter noise in the reconstruction of the particle distribution function. As a specific application we consider Monte Carlo simulations of plasma collisional relaxation and guiding-center transport in magnetically confined plasma in toroidal geometry [1]. We also discuss recent results on the application of POD methods to PIC-codes in the context of the Vlasov-Poisson system, and the use of POD methods in projective integration. In particular, we show how POD modes can be used as effective macroscopic variables to accelerate Monte-Carlo calculations. [1] D. del-Castillo-Negrete, et al. Phys. of Plasmas 15, 092308 (2008).
ICRF Plasma Loading Comparison of Calculations to Measurements in VX-10
NASA Astrophysics Data System (ADS)
Squire, J. P.; Chang-Diaz, F. R.; Ilin, A. V.; Jacobson, V. T.; Glover, T. W.; McCaskill, G. E.; Baity, F. W.; Carter, M. D.; Goulding, R. H.
2003-10-01
The VASIMR propulsion concept accelerates ions using ion cyclotron resonance. ICRF power is applied to an antenna on the high field side of the fundamental resonance. The antenna is designed to launch the Ion Cyclotron Wave (ICW) primarily downstream to the resonance in the flowing plasma. Such an antenna has been installed in the VX-10 experiment for low power testing on a flowing helicon discharge with a high degree of ionization. Plasma loading measurements at about 2 MHz are made with a tuned resonant high Q circuit and an HP network analyzer. Measurements with up to 1.5 kW of applied power are also made. Plasma conditions are held constant from shot-to-shot while the tuned frequency is scanned. This scan is repeated for several different parameters, e.g. magnetic field strength, magnetic polarity, discharge species (D2, He and Ar), and plasma density. Results from a reduced order calculation agree well with experiment and illustrate the significance of the Doppler shift. Measured plasma loading as compared to calculation will be presented and discussed.
NASA Astrophysics Data System (ADS)
Tsigaras, Giannis; Spiliopoulos, Nikolaos; Amanatides, Eleftherios; Mataras, Dimitrios; Plasma Technology Laboratory-Department of Chemical Engineering-University of Patras Team
2016-09-01
Despite the steps forward in the plasma processing of materials, there are still open issues concerning the design of plasma systems and the effective control of plasma parameters. In this work, a comparison between different methods for the measurement and calculation of discharge electrical characteristics is presented. The measurements were accomplished in a laboratory scale cylindrical 13.56 MHz CCP reactor and three different methods were tested: (a) A two port network based technique (b) A distributed element model method and (c) A method based on the solution of the wave equation. The differences between the results of these techniques are discussed in terms of the assumptions that are adopted in each of them. Moreover, the effect of electrode geometry on plasma electrical and microscopic properties was investigated. Two different electrodes were used and changes on the power transfer, plasma current and impedance were monitored together with variations of spatiotemporal emission in 13.56 MHz Ar discharges. Finally, the calculated delivered power error as a function of small measured errors for each method is presented.
Plasma and liquid-metal resistivity calculations using the Ziman theory
NASA Astrophysics Data System (ADS)
Nardi, Eran
1996-08-01
Liquid-metal and dense plasma resistivities are calculated for some transition metals and for Al using the Ziman theory together with the self-consistent average atom INFERNO code. The hypernetted-chain equation is used for calculating the structure factors when no experimental data are available. Attempts are made to improve upon previous calculations by including more accurate electron densities of states as well as the second and third order terms in the multiple scattering expansion of the T matrix. Calculated resistivities with the exception of low density Cu plasma are up to a factor of 4 higher than the experiment for transition metals and between three to four times smaller for Al liquid metal and plasma. The results of the model used in this paper do not seem to agree with the recent experimental data for Cu at a density of the order of a gram and temperatures of several eV as recently obtained by DeSilva and Kunze [Phys. Rev. E 49, 4448 (1994)].
Transport timescale calculations of sawteeth and helical structures in non-circular tokamak plasmas
NASA Astrophysics Data System (ADS)
Jardin, Stephen; Ferraro, Nate; Breslau, Josh; Chen, Jin
2012-10-01
We present results of using the implicit 3D MHD code M3D-C^1 [1,2] to perform 3D nonlinear magnetohydrodynamics calculations of the internal dynamics of a shaped cross-section tokamak plasma that span the timescales associated with ideal and resistive stability as well as parallel and perpendicular transport. We specify the transport coefficients and apply a ``current controller'' that adjusts the boundary loop-voltage to keep the total plasma current fixed. The 3D 2-fluid plasma model advances the magnetic field, velocities, electron and ion temperatures, and plasma density. We find that the plasma either reaches a stationary quasi-helical state in which the central safety factor is approximately unity, or it periodically undergoes either simple or compound sawtooth oscillations [3] with a period that approaches a constant value. By comparing a dee-shaped cross section with an elliptical shaped cross section, it is shown that the plasma shape has a large effect on determining the sawtooth behavior and the associated mode activity. Application to ITER shaped tokamak plasmas predict the magnitude of the 3D boundary deformation as a result of a stationary quasi-helical state forming in the interior. [4pt] [1] J. Breslau, N. Ferraro, S.C. Jardin, Physics of Plasmas 16 092503 (2009) [0pt] [2] S. C. Jardin, N. Ferraro, J. Breslau, J. Chen, Computational Science and Discovery 5 014002 (2012) [0pt] [3] X. von Goeler, W. Stodiek, and N. Sauthoff, Phys. Rev. Lett. 33, 1201 (1974)
A project based on multi-configuration Dirac-Fock calculations for plasma spectroscopy
NASA Astrophysics Data System (ADS)
Comet, M.; Pain, J.-C.; Gilleron, F.; Piron, R.
2017-09-01
We present a project dedicated to hot plasma spectroscopy based on a Multi-Configuration Dirac-Fock (MCDF) code, initially developed by J. Bruneau. The code is briefly described and the use of the transition state method for plasma spectroscopy is detailed. Then an opacity code for local-thermodynamic-equilibrium plasmas using MCDF data, named OPAMCDF, is presented. Transition arrays for which the number of lines is too large to be handled in a Detailed Line Accounting (DLA) calculation can be modeled within the Partially Resolved Transition Array method or using the Unresolved Transition Arrays formalism in jj-coupling. An improvement of the original Partially Resolved Transition Array method is presented which gives a better agreement with DLA computations. Comparisons with some absorption and emission experimental spectra are shown. Finally, the capability of the MCDF code to compute atomic data required for collisional-radiative modeling of plasma at non local thermodynamic equilibrium is illustrated. In addition to photoexcitation, this code can be used to calculate photoionization, electron impact excitation and ionization cross-sections as well as autoionization rates in the Distorted-Wave or Close Coupling approximations. Comparisons with cross-sections and rates available in the literature are discussed.
Multi-CPU plasma fluid turbulence calculations on a CRAY Y-MP C90
Lynch, V.E.; Carreras, B.A.; Leboeuf, J.N.; Curtis, B.C.; Troutman, R.L.
1993-06-01
Significant improvements in real-time efficiency have been obtained for plasma fluid turbulence calculations by microtasking the nonlinear fluid code KITE in which they are implemented on the CRAY Y-MP C90 at the National Energy Research Supercomputer Center (NERSC). The number of processors accessed concurrently scales linearly with problem size. Close to six concurrent processors have so far been obtained with a three-dimensional nonlinear production calculation at the currently allowed memory size of 80 Mword. With a calculation size corresponding to the maximum allowed memory of 200 Mword in the next system configuration, we expect to be able to access close to nine processors of the C90 concurrently with a commensurate improvement in real-time efficiency. These improvements in performance are comparable to those expected from a massively parallel implementation of the same calculations on the Intel Paragon.
Calculation of a plasma HgDyI3 transport coefficients
NASA Astrophysics Data System (ADS)
Hajji, S.; HadjSalah, S.; Benhalima, A.; Charrada, K.; Zissis, G.
2015-05-01
This work is devoted to the calculation of the chemical composition and transport coefficients of HgDyI3 plasmas in thermal equilibrium. These calculations are performed for pressures equal to 2MP and for temperatures varying from 1000 to 10 000 K. The thermal and electrical conductivity as well as viscosity have been computed as a function of temperature at different atomic ratios. The computational method proposed by Devoto from the classical formalism described by Hirschfelder et al. [Molecular Theory of Gases and Liquids (John Wiley and Sons, New York, 1954)] is used.
Atomic Data and Their Application in Calculation of Plasma Radiative Properties
Han Xiaoying; Zhang Hong; Liu Chunlei; Zeng Siliang; Li Dafang; Zhang Yu; Li Yueming; Wu Zeqing; Bao Lihua; Yan Jun
2011-05-11
The Atomic and Molecular Data Research Center in the Institute of Applied Physics and Computational Mathematics has developed systemic code suites to calculate the atomic data including energy levels, cross sections and/or rate coefficients for radiative transition and electron collision with ion. Based on the data, codes were developed to calculate the radiative properties of both local-thermodynamic-equilibrium (LTE) and non-LTE plasmas in the framework of detailed configuration accounting model and detailed level accounting model. The recent work of above aspects, as well as the recent activities of Chinese Research Association of Atomic and Molecular Data will be introduced.
Calculation and observation of thermal electrostatic noise in solar wind plasma
NASA Technical Reports Server (NTRS)
Kellogg, P. J.
1981-01-01
Calculations, both approximate algebraic and numerical, have been carried out for the noise due to electrostatic waves incident on a dipole antenna. The noise is calculated both for a thermal equilibrium plasma, and one having several components at different temperatures. The results are compared with measurements from the IMP-6 satellite. In various frequency ranges, the noise power is dominated by Langmuir oscillations, by electron acoustic waves and by ion acoustic waves. The measurements are consistent with all of these, although the ion waves are not definitely observed, due to interference from shot noise.
Multi-Center Electronic Structure Calculations for Plasma Equation of State
Wilson, B G; Johnson, D D; Alam, A
2010-12-14
We report on an approach for computing electronic structure utilizing solid-state multi-center scattering techniques, but generalized to finite temperatures to model plasmas. This approach has the advantage of handling mixtures at a fundamental level without the imposition of ad hoc continuum lowering models, and incorporates bonding and charge exchange, as well as multi-center effects in the calculation of the continuum density of states.
Study of plasma equilibrium in toroidal fusion devices using mesh-free numerical calculation method
NASA Astrophysics Data System (ADS)
Rasouli, C.; Abbasi Davani, F.; Rokrok, B.
2016-08-01
Plasma confinement using external magnetic field is one of the successful ways leading to the controlled nuclear fusion. Development and validation of the solution process for plasma equilibrium in the experimental toroidal fusion devices is the main subject of this work. Solution of the nonlinear 2D stationary problem as posed by the Grad-Shafranov equation gives quantitative information about plasma equilibrium inside the vacuum chamber of hot fusion devices. This study suggests solving plasma equilibrium equation which is essential in toroidal nuclear fusion devices, using a mesh-free method in a condition that the plasma boundary is unknown. The Grad-Shafranov equation has been solved numerically by the point interpolation collocation mesh-free method. Important features of this approach include truly mesh free, simple mathematical relationships between points and acceptable precision in comparison with the parametric results. The calculation process has been done by using the regular and irregular nodal distribution and support domains with different points. The relative error between numerical and analytical solution is discussed for several test examples such as small size Damavand tokamak, ITER-like equilibrium, NSTX-like equilibrium, and typical Spheromak.
Study of plasma equilibrium in toroidal fusion devices using mesh-free numerical calculation method
Rasouli, C.; Abbasi Davani, F.; Rokrok, B.
2016-08-15
Plasma confinement using external magnetic field is one of the successful ways leading to the controlled nuclear fusion. Development and validation of the solution process for plasma equilibrium in the experimental toroidal fusion devices is the main subject of this work. Solution of the nonlinear 2D stationary problem as posed by the Grad-Shafranov equation gives quantitative information about plasma equilibrium inside the vacuum chamber of hot fusion devices. This study suggests solving plasma equilibrium equation which is essential in toroidal nuclear fusion devices, using a mesh-free method in a condition that the plasma boundary is unknown. The Grad-Shafranov equation has been solved numerically by the point interpolation collocation mesh-free method. Important features of this approach include truly mesh free, simple mathematical relationships between points and acceptable precision in comparison with the parametric results. The calculation process has been done by using the regular and irregular nodal distribution and support domains with different points. The relative error between numerical and analytical solution is discussed for several test examples such as small size Damavand tokamak, ITER-like equilibrium, NSTX-like equilibrium, and typical Spheromak.
Calculations of axisymmetric stability of tokamak plasmas with active and passive feedback
Ward, D.J.; Jardin, S.C.; Cheng, C.Z.
1991-07-01
A new linear MHD stability code, NOVA-W, has been developed in order to study feedback stabilization of the axisymmetric mode in deformable tokamak plasmas. The NOVA-W code is a modification of the non-variational MHD stability code NOVA that includes the effects of resistive passive conductors and active feedback circuits. The vacuum calculation has been reformulated in terms of the perturbed poloidal flux to allow the inclusion of perturbed toroidal currents outside the plasma. The boundary condition at the plasma-vacuum interface relates the instability displacement to the perturbed poloidal flux. This allows a solution of the linear MHD stability equations with the feedback effects included. The passive stability predictions of the code have been tested both against a simplified analytic model and against a different numerical calculation for a realistic tokamak configuration. The comparisons demonstrate the accuracy of the NOVA-W results. Active feedback calculations are performed for the CIT tokamak design demonstrating the effect of varying the position of the flux loops that provide the measurements of vertical displacement. The results compare well with those computed earlier using a less efficient nonlinear code. 37 refs., 13 figs.
Morel, P.; Meot, V.; Gosselin, G.; Faussurier, G.; Blancard, C.
2010-03-15
The nuclear excitation by electron capture (NEET) process may occur when the energy differences between two nuclear levels and between two electronic states are nearly equal, provided the quantum selection rules are fulfilled. These resonant conditions drastically limit the number of possible candidates, even though thermodynamic conditions encountered in hot dense plasmas do modify the orbital electronic binding energy and the resonance conditions. {sup 201}Hg, with a low-lying isomeric state located at 1.565 keV, can be excited by NEET process in a laser-created plasma. However, its correct calculation requires nonlocal thermodynamic equilibrium (non-LTE) atomic physics treatment because current laser-created plasmas do not reach high-enough temperature in the area at LTE. In this article, we describe the calculation leading to an estimated excitation rate and discuss the influence of LTE/non-LTE physics with an average-atom model and the use of a Gaussian variance calculation to estimate the broadening around the mean energy mismatch.
Preface to Special Topic: Advances in Radio Frequency Physics in Fusion Plasmas
NASA Astrophysics Data System (ADS)
Tuccillo, Angelo A.; Phillips, Cynthia K.; Ceccuzzi, Silvio
2014-06-01
It has long been recognized that auxiliary plasma heating will be required to achieve the high temperature, high density conditions within a magnetically confined plasma in which a fusion "burn" may be sustained by copious fusion reactions. Consequently, the application of radio and microwave frequency electromagnetic waves to magnetically confined plasma, commonly referred to as RF, has been a major part of the program almost since its inception in the 1950s. These RF waves provide heating, current drive, plasma profile control, and Magnetohydrodynamics (MHD) stabilization. Fusion experiments employ electromagnetic radiation in a wide range of frequencies, from tens of MHz to hundreds of GHz. The fusion devices containing the plasma are typically tori, axisymmetric or non, in which the equilibrium magnetic fields are composed of a strong toroidal magnetic field generated by external coils, and a poloidal field created, at least in the symmetric configurations, by currents flowing in the plasma. The waves are excited in the peripheral regions of the plasma, by specially designed launching structures, and subsequently propagate into the core regions, where resonant wave-plasma interactions produce localized heating or other modification of the local equilibrium profiles. Experimental studies coupled with the development of theoretical models and advanced simulation codes over the past 40+ years have led to an unprecedented understanding of the physics of RF heating and current drive in the core of magnetic fusion devices. Nevertheless, there are serious gaps in our knowledge base that continue to have a negative impact on the success of ongoing experiments and that must be resolved as the program progresses to the next generation devices and ultimately to "demo" and "fusion power plant." A serious gap, at least in the ion cyclotron (IC) range of frequencies and partially in the lower hybrid frequency ranges, is the difficulty in coupling large amount of power to the
Preface to Special Topic: Advances in Radio Frequency Physics in Fusion Plasmas
Tuccillo, Angelo A.; Ceccuzzi, Silvio; Phillips, Cynthia K.
2014-06-15
It has long been recognized that auxiliary plasma heating will be required to achieve the high temperature, high density conditions within a magnetically confined plasma in which a fusion “burn” may be sustained by copious fusion reactions. Consequently, the application of radio and microwave frequency electromagnetic waves to magnetically confined plasma, commonly referred to as RF, has been a major part of the program almost since its inception in the 1950s. These RF waves provide heating, current drive, plasma profile control, and Magnetohydrodynamics (MHD) stabilization. Fusion experiments employ electromagnetic radiation in a wide range of frequencies, from tens of MHz to hundreds of GHz. The fusion devices containing the plasma are typically tori, axisymmetric or non, in which the equilibrium magnetic fields are composed of a strong toroidal magnetic field generated by external coils, and a poloidal field created, at least in the symmetric configurations, by currents flowing in the plasma. The waves are excited in the peripheral regions of the plasma, by specially designed launching structures, and subsequently propagate into the core regions, where resonant wave-plasma interactions produce localized heating or other modification of the local equilibrium profiles. Experimental studies coupled with the development of theoretical models and advanced simulation codes over the past 40+ years have led to an unprecedented understanding of the physics of RF heating and current drive in the core of magnetic fusion devices. Nevertheless, there are serious gaps in our knowledge base that continue to have a negative impact on the success of ongoing experiments and that must be resolved as the program progresses to the next generation devices and ultimately to “demo” and “fusion power plant.” A serious gap, at least in the ion cyclotron (IC) range of frequencies and partially in the lower hybrid frequency ranges, is the difficulty in coupling large amount of
Nonlinear scattering from a plasma column. I - Theory. II Special cases
NASA Technical Reports Server (NTRS)
Crawford, F. W.; Harker, K. J.
1983-01-01
The scattered signal excited by nonlinear mixing of two plane waves normally incident on an infinitely long column of plasma is investigated. A general solution is obtained for the polarization in which the electric field vectors of the waves are perpendicular to the column axis and the column is assumed to be radically inhomogeneous. This general theory is then applied to the special cases of the inhomogeneous column in the long-wavelength limit, and the homogeneous column both for the general case and in the long-wavelength limit. It is determined that dipole and quadrupole components should predominate in the polar radiation pattern for the long-wavelength case. The special case of second harmonic generation due to a single incident wave is analyzed in detail. Nonlinear scattering coefficients are computed, and the corresponding polar radiation patterns are determined. The findings of this study are employed to evaluate the feasibility of observing nonlinear scattering from meteor trails.
Liu, Li; Xiao, Ping-ping
2016-02-01
Temperature is one of the most important parameters in studying of laser-induced plasma characteristics. To reduce the impact of continuous background on the calculation of temperatures using Boltzmann plots, the wavelet transform was used to decompose the spectrums, and the low-frequency signals represented the spectral baseline were deducted by using soft-threshold method. Selecting the appropriate wavelet decomposition level L and threshold coefficient a can increase the linear regression coefficient R2 of Boltzmann plots, and the calculation accuracy of plasma temperature was improved. The LIBS spectra of low alloy steel sample region from 417 to 445 nm were decomposed by using db4 wavelet, and then baseline subtraction and signal reconstruction were carried out, respectively. Twelve Fe atomic lines were chosen to establish Boltzmann plots, and the temperatures were calculated from the slope of the fitted lines in the plots. The value L and a were optimized according R², the results showed that the 8-layer db4 wavelet decomposition can gain the high R², while the value of a associated with the delay time td, e. g. , the optimum a corresponding to maximum values of R² is 0.3 when td ≤ 4.0 µs, and then decrease with the increasing of td, and reduced to 0 when td ≥ 6. 0 µs. The interference due to baseline on the spectral characteristic lines gradually reduced with the increasing of td, and therefore a decreased with td increase. After the baseline was deducted, the temperature calculated by Boltzmann plot decrease of about 2 000 to 3 000 K. The temperature gradually decreased with the increasing of the td, and the temperature fluctuation is reduced after baseline subtraction, these results are consistent with the physical process of plasma expansion.
Global, Gyrokinetic Eigenvalue Calculations of ITG-Related Microinstabilities in Tokamak Plasmas
NASA Astrophysics Data System (ADS)
Brunner, S.; Fivaz, M.; Tran, T. M.; Vaclavik, J.
1998-11-01
Methods previously developed for a cylindrical system(S.Brunner and J.Vaclavik, Phys.Plasmas 5), 365 (1998) have been generalized to a tokamak plasma for solving the full 2-dimensional eigenvalue problem of electrostatic microinstabilities using a gyrokinetik model(S.Brunner, Ph.D thesis, Ecole Polytechnique Fédérale de Lausanne, Switzerland, thesis 1701 (1978)). By solving the spectral problem in a special Fourier space adapted to the curved geometry, orbit width as well as Larmor radius can be kept to all orders. For a first numerical implementation, a large aspect ratio plasma with circular concentric magnetic surfaces has been considered. A higher order Nyquist method(B.Davies, Jour.Comp.Phys. 66), 36 (1986), applied for identifying the eigenfrequencies in the complex plane, has been improved and enables straightforward implementation on a parallel computer. Illustrative results of ITG (ion temperature gradient) -related instabilities are presented. These include scaling studies of the radial width, toroidicity and magnetic shear scans, as well as the effects of non-adiabatic trapped electron dynamics.
NASA Astrophysics Data System (ADS)
Sisev, A. A.; Paderin, S. N.; Troyanov, K. V.
2015-06-01
The thermodynamic calculations of the equilibrium activities of oxygen with deoxidizers Al, Ca, Mg, Ti, La, and Ce are performed from the compositions of metal samples taken during melting of special alloys in a vacuum induction furnace. The emf was measured simultaneously with sampling during the immersion of an oxygen sensor into a liquid metal. The results of calculations of the equilibrium oxygen activities with each deoxidizer are compared to the oxygen activities calculated by the measured values of emf and the temperature metal.
Core Physics and Kinetics Calculations for the Fissioning Plasma Core Reactor
NASA Technical Reports Server (NTRS)
Butler, C.; Albright, D.
2007-01-01
Highly efficient, compact nuclear reactors would provide high specific impulse spacecraft propulsion. This analysis and numerical simulation effort has focused on the technical feasibility issues related to the nuclear design characteristics of a novel reactor design. The Fissioning Plasma Core Reactor (FPCR) is a shockwave-driven gaseous-core nuclear reactor, which uses Magneto Hydrodynamic effects to generate electric power to be used for propulsion. The nuclear design of the system depends on two major calculations: core physics calculations and kinetics calculations. Presently, core physics calculations have concentrated on the use of the MCNP4C code. However, initial results from other codes such as COMBINE/VENTURE and SCALE4a. are also shown. Several significant modifications were made to the ISR-developed QCALC1 kinetics analysis code. These modifications include testing the state of the core materials, an improvement to the calculation of the material properties of the core, the addition of an adiabatic core temperature model and improvement of the first order reactivity correction model. The accuracy of these modifications has been verified, and the accuracy of the point-core kinetics model used by the QCALC1 code has also been validated. Previously calculated kinetics results for the FPCR were described in the ISR report, "QCALC1: A code for FPCR Kinetics Model Feasibility Analysis" dated June 1, 2002.
Zheng, Kai; Li, Huan; Yang, Li-Jun; Gu, Xiao-Yan; Gao, Ying
2013-04-01
The plasma radiation of laser-double wire hybrid welding was collected by using fiber spectrometer, the coupling mechanism of arc with laser was studied through high-speed photography during welding process, and the temperature of hybrid plasma was calculated by using the method of Boltzmann plot. The results indicated that with laser hybrid, luminance was enhanced; radiation intensity became stronger; arc was attracted to the laser point; cross section contracted and arc was more stable. The laser power, welding current and arc-arc distance are important factors that have great influence on electron temperature. Increase in the laser power, amplification of welding current and reduction of arc-arc distance can all result in the rise of temperature.
MCDHF calculations and study of plasma parameters for Li-like ions
NASA Astrophysics Data System (ADS)
Khatri, Indu; Goyal, Arun; Aggarwal, Sunny; Singh, A. K.; Man Mohan
2016-06-01
Extensive configuration interaction calculations for several Li-like ions (Z=32, 36, 42, 46, 50, 54 and 56) are performed using the code GRASP2K based on the multiconfiguration Dirac-Hartree-Fock (MCDHF) method. Breit interaction and leading quantum electrodynamical (QED) effects are also included by applying active-space techniques to enlarge the configuration set. Results for fine-structure energy levels for 1s22p, 1s23s, 1s23p and 1s23d configurations with relative to ground states 1s22s are presented. The wavelengths, transition rates and oscillator strengths for the 1s22s 2S1/2-1s22p 1/2,3/2,0 2P, 1s22p 1/2,3/2,0,2P - -1s23s 2S1/2, 1s22p calculated results are in good agreement with previous theoretical results and compiled values of the National Institute for Standards and Technology (NIST). We have also provided the line intensity ratios and plasma parameters for optically thin plasma. Our calculated data may be useful for experimentalists in identifying the fine-structure levels, for plasma modeling, astrophysical research applications.
Hamiltonian guiding center drift orbit calculation for toroidal plasmas of arbitrary cross section
White, R.B.; Chance, M.S.
1984-02-01
A Hamiltonian guiding center drift orbit formalism is developed which permits the efficient calculation of particle trajectories in toroidal devices of arbitrary cross section with arbitrary plasma ..beta... The magnetic field is assumed to be a small perturbation from a zero order toroidal equilibrium field possessing either axial or helical symmetry. The equilibrium field can be modelled analytically or obtained numerically from equilibrium codes. A numerical code based on the formalism is used to study particle orbits in circular and bean-shaped tokamak configurations.
Plasma drift-kinetic equation calculations in three-dimensional magnetic geometries
Reynolds, J. M.; Lopez-Bruna, D.
2010-07-15
A new code to simulate three-dimensional plasmas in complex toroidal geometries is presented. It solves drift-kinetic equations for the one-particle distribution function f based on their projection onto a functional basis consisting of an arbitrary number of Legendre-Laguerre polynomials. In this paper, these theoretical aspects of the code are exposed together with their relation with the standard formalism. Comparisons with neoclassical theory for the large aspect ratio case and first calculations in the geometry of the TJ-II Heliac are also presented.
Calculation of thermodynamic functions of aluminum plasma for high-energy-density systems
Shumaev, V. V.
2016-12-15
The results of calculating the degree of ionization, the pressure, and the specific internal energy of aluminum plasma in a wide temperature range are presented. The TERMAG computational code based on the Thomas–Fermi model was used at temperatures T > 105 K, and the ionization equilibrium model (Saha model) was applied at lower temperatures. Quantitatively similar results were obtained in the temperature range where both models are applicable. This suggests that the obtained data may be joined to produce a wide-range equation of state.
Beta electron fluxes inside a magnetic plasma cavern: Calculation and comparison with experiment
NASA Astrophysics Data System (ADS)
Stupitskii, E. L.; Smirnov, E. V.; Kulikova, N. A.
2010-12-01
We study the possibility of electrostatic blanking of beta electrons in the expanding spherical blob of a radioactive plasma in a rarefied ionosphere. From numerical studies on the dynamics of beta electrons departing a cavern, we obtain the form of a function that determines the portion of departing electrons and calculate the flux density of beta electrons inside the cavern in relation to the Starfish Prime nuclear blast. We show that the flux density of electrons in geomagnetic flux tubes and inside the cavern depend on a correct allowance for the quantity of beta electrons returning to the cavern. On the basis of a physical analysis, we determine the approximate criterion for the return of electrons from a geomagnetic flux tube to the cavern. We compare calculation results in terms of the flux density of beta electrons inside the cavern with the recently published experimental results from operation Starfish Prime.
Thomas, Johannes Pronold, Jari; Pukhov, Alexander; Kostyukov, Igor Yu.; Golovanov, Anton
2016-05-15
We introduce a complete semi-analytical model for a cavitated electron wake driven by an electron beam in a radially inhomogeneous plasma. The electron response to the driver, dynamics of electrons in a thin sheath surrounding the cavity, as well as accelerating and focusing fields inside the cavity are calculated in the quasistatic approximation. Our theory holds for arbitrary radial density profiles and reduces to known models in the limit of a homogeneous plasma. A free-propagating blow-out in an evacuated channel experiences longitudinal squeezing, qualitatively the same as observed in particle-in-cell simulations for the laser pulse-driven case [Pukhov et al., Phys. Rev. Lett. 113, 245003 (2014)]. Our model also permits qualitative interpretation of the earlier observed cancellation of the focusing gradient in the cavity [Pukhov et al., Phys. Rev. Lett. 113, 245003 (2014)]. In this work, we show the underlying mechanism that causes the radial fields in the vacuum part of a channel to become defocussing.
NASA Astrophysics Data System (ADS)
Shahzad, Aamir; He, Mao-Gang
2015-09-01
The heat conductivity of three-dimensional Yukawa dusty plasma liquids (YDPLs) has been investigated by employing a homogenous nonequilibrium molecular dynamics (HNEMD) technique at a low normalized force field strength (F*). The obtained results for plasma heat conductivity with suitable normalizations are measured over a wide range of various plasma states of the Coulomb coupling (Γ) and screening length (κ) in a canonical ensemble (NVT). The calculations for lattice correlations (Ψ) show that our YDPLs system remains in a nonideal strongly coupled regime for a complete range of Γ. It has been shown that the presented Yukawa system obeys a simple analytical temperature demonstration of λ0 with a normalized Einstein frequency. The employed HNEMD algorithm is found to have a more efficient method than that of different earlier numerical methods and it gives more satisfactory results for lower to intermediate Γ with small system sizes at low F*. The obtained simulation results at nearly equilibrium F* (= 0.002) are in reasonable agreement with different earlier numerical results and with the present reference set of data showed deviations within less than ±15% for most of the present data points and generally underpredicted the λ0 by 2-22%, depending on (Γ, κ).
NASA Technical Reports Server (NTRS)
Mcintyre, R. G.; Bruce, R. E.
1974-01-01
The effect of the calculation of the cluster integrals on three particles is analyzed and evaluated for a hydrogen plasma where a pairwise-additive hard sphere-Coulomb potential is assumed. The Mayer cluster integral method was used to calculate the Helmholtz free energy which was then applied to the calculation of the electron number density through an iterative technique using a corrected Saha equation. It is seen that the three particle integrals provide a substantial correction to the calculations in the low energy-high density region of the hydrogen plasma.
NASA Technical Reports Server (NTRS)
Mcintyre, R. G.; Bruce, R. E.
1974-01-01
The effect of the calculation of the cluster integrals on three particles is analyzed and evaluated for a hydrogen plasma where a pairwise-additive hard sphere-Coulomb potential is assumed. The Mayer cluster integral method was used to calculate the Helmholtz free energy which was then applied to the calculation of the electron number density through an iterative technique using a corrected Saha equation. It is seen that the three particle integrals provide a substantial correction to the calculations in the low energy-high density region of the hydrogen plasma.
Refined Calculations of Secondary Nuclear Reactions in Magneto-Inertial Fusion Plasmas
NASA Astrophysics Data System (ADS)
Schmit, Paul; Knapp, Patrick; Hansen, Stephanie; Gomez, Matthew; Hahn, Kelly; Sinars, Daniel; Peterson, Kyle; Slutz, Stephen; Sefkow, Adam; Awe, Thomas; Harding, Eric; Jennings, Christopher
2014-10-01
Diagnosing the degree of magnetic flux compression at stagnation in magneto-inertial fusion (MIF) is critical for charting the performance of any MIF concept. In pure deuterium plasma, the transport of high-energy tritons produced by the aneutronic DD fusion reaction depends strongly on the magnetic field. The tritons probe and occasionally react with the fuel, emitting secondary DT neutrons. We show that the DT/DD neutron yield ratio and the secondary DT neutron spectra can be used to infer the magnetic field-radius product (BR), the critical confinement parameter for MIF. The amount of fuel-pusher mix also can be constrained by secondary reactions. We discuss the sensitivity to plasma inhomogeneities of the calculations and outline methods to relate secondary yields to alpha particle energy deposition in ignition-relevant experiments employing DT fuel. We compare our calculations to recent tests of the Magnetized Liner Inertial Fusion (MagLIF) concept on the Z Pulsed Power Facility. Supported in part by the SNL Truman Fellowship, which is part of the LDRD Program, and sponsored by Sandia Corporation (a wholly owned subsidiary of Lockheed Martin Corporation) as Operator of SNL under its U.S. DoE Contract No. DE-AC04-94AL85000.
Venous and fingertip blood to calculate plasma volume shift following exercise.
Knowlton, R G; Brown, D D; Hetzler, R K; Sikora, L M
1990-12-01
This study determined whether fingertip blood samples used to calculate percentage change in calculated plasma volume following exercise were in agreement with values obtained from venous blood samples. Twenty-five subjects engaged in two cycle ergometer exercises at 100 and 200 W, with percentage plasma volume shift (% PVS) determined after each from venous (VB) and fingertip (FT) blood. Values for % PVS were FT -6.25% compared with VB -8.04% (P less than 0.05), with the correlation between the two methods at r = 0.88. The following equation was established: corrected FT % PVS = (0.8662 * FT) - 2.625; SEE = 2.60%. In order to cross-validate this equation, fifteen additional subjects submitted to VB and FT. Corrected FT % PVS using the established equation resulted in a mean value of 9.53 compared with 10.53% for actual VB % PVS. Although these means were not significantly different, there was approximately a 25% chance that the corrected FT % PVS would be more than one standard error of estimate from the regression line. It was concluded that FT underestimates VB % PVS. However, when limited to group data, FT can be corrected to favorably represent VB % PVS following moderate to heavy cycle ergometer exercise.
Yamamoto, K.; Mizuno, Y.; Hibino, S.; Inuzuka, H.; Cao, Y.; Liu, Y.; Yazawa, K.
2006-01-15
Simulations of dusty plasmas were performed using GRAPE-6, a special-purpose computer designed for gravitational N-body problems. The collective behavior of dust particles, which are injected into the plasma, was studied by means of three-dimensional computer simulations. As an example of a dusty plasma simulation, experiments on Coulomb crystals in plasmas are simulated. Formation of a quasi-two-dimensional Coulomb crystal has been observed under typical laboratory conditions. Another example was to simulate movement of dust particles in plasmas under microgravity conditions. Fully three-dimensional spherical structures of dust clouds have been observed. For the simulation of a dusty plasma in microgravity with 3x10{sup 4} particles, GRAPE-6 can perform the whole operation 1000 times faster than by using a Pentium 4 1.6 GHz processor.
Kokkoris, George; Boudouvis, Andreas G.; Gogolides, Evangelos
2006-11-15
An integrated framework for the neutral flux calculation inside trenches and holes during plasma etching is described, and a comparison between the two types of structure in a number of applications is presented. First, a detailed and functional set of equations for the neutral and ion flux calculations inside long trenches and holes with cylindrical symmetry is explicitly formulated. This set is based on early works [T. S. Cale and G. B. Raupp, J. Vac. Sci. Technol. B 8, 1242 (1990); V. K. Singh et al., J. Vac. Sci. Technol. B 10, 1091 (1992)], and includes new equations for the case of holes with cylindrical symmetry. Second, a method for the solution of the respective numerical task, i.e., one or a set of linear or nonlinear integral equations, is described. This method includes a coupling algorithm with a surface chemistry model and resolves the singularity problem of the integral equations. Third, the fluxes inside trenches and holes are compared. The flux from reemission is the major portion of the local flux at the bottom of both types of structure. The framework is applied in SiO{sub 2} etching by fluorocarbon plasmas to predict the increased intensity of reactive ion etching lag in SiO{sub 2} holes compared to trenches. It is also applied in deep Si etching: By calculating the flux of F atoms at the bottom of very high aspect ratio (up to 150) Si trenches and holes during the gas chopping process, the aspect ratio at which the flux of F atoms is eliminated and etching practically stops is estimated.
Special methods for aerodynamic-moment calculations from parachute FSI modeling
NASA Astrophysics Data System (ADS)
Takizawa, Kenji; Tezduyar, Tayfun E.; Boswell, Cody; Tsutsui, Yuki; Montel, Kenneth
2015-06-01
The space-time fluid-structure interaction (STFSI) methods for 3D parachute modeling are now at a level where they can bring reliable, practical analysis to some of the most complex parachute systems, such as spacecraft parachutes. The methods include the Deforming-Spatial-Domain/Stabilized ST method as the core computational technology, and a good number of special FSI methods targeting parachutes. Evaluating the stability characteristics of a parachute based on how the aerodynamic moment varies as a function of the angle of attack is one of the practical analyses that reliable parachute FSI modeling can deliver. We describe the special FSI methods we developed for this specific purpose and present the aerodynamic-moment data obtained from FSI modeling of NASA Orion spacecraft parachutes and Japan Aerospace Exploration Agency (JAXA) subscale parachutes.
ERIC Educational Resources Information Center
Luna, Pat
Designed for middle school students, this award winning, six-day teaching unit helped students learn about the concepts of specialization, interdependence, efficiency, and profit. At the onset of the lesson the students were already familiar with the concepts of scarcity, goods, services, profits, supply, demand, and opportunity costs. The unit's…
Ligot, S; Guillaume, M; Gerbaux, P; Thiry, D; Renaux, F; Cornil, J; Dubois, P; Snyders, R
2014-04-17
The focus of this work is on the growth mechanism of ethyl lactate-based plasma polymer film (ELPPF) that could be used as barrier coatings. In such an application, the ester density of the plasma polymer has to be controlled to tune the degradation rate of the material. Our strategy consists of correlating the plasma chemistry evaluated by RGA mass spectrometry and understanding, via DFT calculations, the chemistry of the synthesized thin films. The theoretical calculations helped us to understand the plasma chemistry in plasma ON and OFF conditions. From these data it is unambiguously shown that the signal m/z 75 can directly be correlated with the precursor density in the plasma phase. The combination of XPS and chemical derivatization experiments reveal that the ester content in the ELPFF can be tailored from 2 to 18 at. % by decreasing the RF power, which is perfectly correlated with the evolution of the plasma chemistry. Our results also highlight that the ELPPF chemistry, especially the ester content, is affected by the plasma mode of operation (continuous or pulsed discharge, at similar injected mean power) for similar ester content in the plasma. This could be related to different energy conditions at the interface of the growing films that could affect the sticking coefficient of the ester-bearing fragments.
Otani, Makoto; Ise, Shiro
2006-05-01
Recently, development of a numerical calculation of the head-related transfer function (HRTF) has been conducted using a computer model of a human head and the boundary element method. The reciprocity theorem is incorporated into the computational process in order to shorten the computational time, which is otherwise very long. On the other hand, another fast HRTF calculation method for any source position, which is realized by calculating factors independent of the source position in advance, has been suggested by the authors. Using this algorithm, the HRTF for any source position can be obtained in a few seconds with a common PC. The resulting HRTFs are more precise and are calculated faster than those by using the reciprocity theorem. However, speeding the process up even further is required in order to respond to a head movement and rotation or to moving sources during binaural sound reproduction. In this paper, a faster calculation method by incorporating a time domain operation into the authors' previous algorithm is proposed. Additionally, the new formulation, which eliminates the extra computational time in the preprocess, is proposed. This method is shown to be faster than the previous ones, but there are some discrepancies at higher frequencies.
R-matrix calculations of electron molecule collision data for plasma models
NASA Astrophysics Data System (ADS)
Tennyson, Jonathan
2016-09-01
Models of low-pressure plasma require electron collision cross sections for many processes. For transient molecular species, almost none of these data are available from laboratory measurements so theory has to be the chosen means of providing the necessary information. The R-matrix method is a well-established fully quantal procedure for computing low-energy electron-collision cross sections. The R-matrix calculations using the UK Molecular R-matrix codes (UKRMol), which are run by the Quantemol-N expert system, are being employed to provide a wide range of collision cross sections. These are augmented by use of suitable high-energy approximations, such as BEB for ionisation, and a novel procedure to give branching ratios for the fragmentation pattern following electron impact ionisation and electron impact dissociation. Examples, such as recently generated complete cross section sets for the molecules NF, NF and NF, will be given at the meeting.
NASA Astrophysics Data System (ADS)
Garcia-Lechuga, M.; Fuentes, L. M.; Grützmacher, K.; Pérez, C.; de la Rosa, M. I.
2014-10-01
We report a detailed characterization of the spatial resolution provided by two-photon absorption spectroscopy suited for plasma diagnosis via the 1S-2S transition of atomic hydrogen for optogalvanic detection and laser induced fluorescence (LIF). A precise knowledge of the spatial resolution is crucial for a correct interpretation of measurements, if the plasma parameters to be analysed undergo strong spatial variations. The present study is based on a novel approach which provides a reliable and realistic determination of the spatial resolution. Measured irradiance distribution of laser beam waists in the overlap volume, provided by a high resolution UV camera, are employed to resolve coupled rate equations accounting for two-photon excitation, fluorescence decay and ionization. The resulting three-dimensional yield distributions reveal in detail the spatial resolution for optogalvanic and LIF detection and related saturation due to depletion. Two-photon absorption profiles broader than the Fourier transform-limited laser bandwidth are also incorporated in the calculations. The approach allows an accurate analysis of the spatial resolution present in recent and future measurements.
Wochyński, Zbigniew; Sobiech, Krzysztof
2017-06-19
This study has aimed at investigating the impact of the Special Aviation Gymnastics Instruments (SAGI) training scheme on the blood serum cortisol, testosterone, insulin, and plasma adrenaline, noradrenaline, and dopamine in comparison with a control group. Fifty-five cadets, aged 20 years old, participated in the study. Cadets were divided into 2 groups: A (N = 41) - the SAGI-trained, and B (N = 14) - the control group. In both groups, blood was the examined material, sampled twice: before the training session (BT) and after the training session (AT), at the beginning (training session I), during (training session II), and after completion of the SAGI training session (training session III). Commercially available kits were used for assaying serum cortisol, testosterone, and insulin as well as plasma adrenaline, noradrenaline, and dopamine. Cadets' physical fitness was assessed by means of Aero-Synthetic Efficiency Tests. In group A, a significant decrease in serum cortisol (training session III) and insulin in three training sessions AT in comparison with the values BT was seen. A statistically significant increase in testosterone and catecholamines was noted in all 3 training sessions AT in comparison with the values BT. In group B, a statistically significant increase in cortisol (training session II), testosterone, and catecholamines was observed in all 3 training sessions AT vs. the values in training session BT. In group B, serum levels of all assayed hormones were higher in training session III than those in group A. In the examined group, the SAGI training produced fewer hormonal changes dependent on the intensity and exercise type and physical efficiency improvement than in the control group. Int J Occup Med Environ Health 2017;30(4):655-664.
NASA Astrophysics Data System (ADS)
Bienkowska, B.; Scholz, M.; Wincel, K.; Zaręba, B.
2008-03-01
In this paper Plasma-Focus (PF) neutron emission properties have been studied using Monte Carlo calculations for neutron and photon transport. A Thermal Neutron Scaling Factor as a function of angular position of silver activation detectors placed around MJ Plasma Focus (PF-1000) device has been calculated. Detector responses calculated for 2.5 MeV neutrons and neutrons produced by Am-Be calibration source have been obtained .The results have shown the detector response dependence on the kind of calibration neutron source and on local geometrical/structural characteristics of the PF-1000 devices. Thus the proper calibration procedure ought to be performed for correct measurement of neutron yield within Plasma-Focus devices.
Special features of design and calculation for structures made of anisotropic fiberglass
NASA Astrophysics Data System (ADS)
Shambina, S. L.; Virchenko, G. A.
2017-07-01
In recent years composite materials find wide application in various fields of engineering, because they have a number of advantages over other structural materials. A variety of composites’ physical and mechanical properties (especially anisotropy) requires an improvement of existing calculation methods and creation of new ones for structural elements made of these materials. This is an important task which will contribute to their wider use. In this paper some famous criteria of anisotropic materials are examined, and their advantages and disadvan-tages are discussed. The authors of the paper suggest new variants of strength criteria for anisotropic materials. These new criteria are based on new mechanical characteristics which are more convenient for experimental obtaining. Also new criteria use separate form of writing for each quadrant of the stress plain.
NASA Astrophysics Data System (ADS)
Han, D.; Wang, J.
2015-12-01
The moon-plasma interactions and the resulting surface charging have been subjects of extensive recent investigations. While many particle-in-cell (PIC) based simulation models have been developed, all existing PIC simulation models treat the surface of the Moon as a boundary condition to the plasma flow. In such models, the surface of the Moon is typically limited to simple geometry configurations, the surface floating potential is calculated from a simplified current balance condition, and the electric field inside the regolith layer cannot be resolved. This paper presents a new full particle PIC model to simulate local scale plasma flow and surface charging. A major feature of this new model is that the surface is treated as an "interface" between two mediums rather than a boundary, and the simulation domain includes not only the plasma but also the regolith layer and the bedrock underneath it. There are no limitations on the surface shape. An immersed-finite-element field solver is applied which calculates the regolith surface floating potential and the electric field inside the regolith layer directly from local charge deposition. The material property of the regolith layer is also explicitly included in simulation. This new model is capable of providing a self-consistent solution to the plasma flow field, lunar surface charging, the electric field inside the regolith layer and the bedrock for realistic surface terrain. This new model is applied to simulate lunar surface-plasma interactions and surface charging under various ambient plasma conditions. The focus is on the lunar terminator region, where the combined effects from the low sun elevation angle and the localized plasma wake generated by plasma flow over a rugged terrain can generate strongly differentially charged surfaces and complex dust dynamics. We discuss the effects of the regolith properties and regolith layer charging on the plasma flow field, dust levitation, and dust transport.
Sauvan, P; Dalimier, E
2009-03-01
The formalism for the calculation of Stark line profiles in hot dense plasmas submitted to a strong oscillating field is extensively developed. The Liouville space, usually used to deal with the calculation of Stark profiles in dense plasmas, and the Floquet theory, developed to solve time-periodic problems, have been joined together to solve the time-dependent Liouville equation in the so-called Floquet-Liouville formalism. The strong-oscillating-field spectroscopic signatures and their error estimations are discussed for hydrogen- and heliumlike aluminum lines.
Calculation of the non-inductive current profile in high-performance NSTX plasmas
NASA Astrophysics Data System (ADS)
Gerhardt, S. P.; Fredrickson, E.; Gates, D.; Kaye, S.; Menard, J.; Bell, M. G.; Bell, R. E.; Le Blanc, B. P.; Kugel, H.; Sabbagh, S. A.; Yuh, H.
2011-03-01
The constituents of the current profile have been computed for a wide range of high-performance plasmas in NSTX (Ono et al 2000 Nucl. Fusion 40 557); these include cases designed to maximize the non-inductive fraction, pulse length, toroidal-β or stored energy. In the absence of low-frequency MHD activity, good agreement is found between the reconstructed current profile and that predicted by summing the independently calculated inductive, pressure-driven and neutral beam currents, without the need to invoke any anomalous beam ion diffusion. Exceptions occur, for instance, when there are toroidal Alfvén eigenmode avalanches or coupled m/n = 1/1 + 2/1 kink-tearing modes. In these cases, the addition of a spatially and temporally dependent fast-ion diffusivity can reduce the core beam current drive, restoring agreement between the reconstructed profile and the summed constituents, as well as bringing better agreement between the simulated and measured neutron emission rate. An upper bound on the fast-ion diffusivity of ~0.5-1 m2 s-1 is found in 'MHD-free' discharges, based on the neutron emission, the time rate of change in the neutron signal when a neutral beam is stepped and reconstructed on-axis current density.
Calculation of the Non-Inductive Current Profile in High-Performance NSTX Plasmas
Gerhardt, S P; Gates, D; Kaye, S; Menard, J; Bell, M G; Bell, R E; Le Blanc, B P; Kugel, H; Sabbagh, S A
2011-02-09
The constituents of the current profile have been computed for a wide range of high-performance plasmas in NSTX [M. Ono, et al., Nuclear Fusion 40, 557 (2000)]; these include cases designed to maximize the non-inductive fraction, pulse length, toroidal-β, or stored energy. In the absence of low-frequency MHD activity, good agreement is found between the reconstructed current profile and that predicted by summing the independently calculated inductive, pressure-driven, and neutral beam currents, without the need to invoke any anomalous beam ion diffusion. Exceptions occur, for instance, when there are toroidal Alfven eigenmode avalanches or coupled m/n=1/1+2/1 kink-tearing modes. In these cases, the addition of a spatially and temporally dependent fast ion diffusivity can reduce the core beam current drive, restoring agreement between the reconstructed profile and the summed constituents, as well as bringing better agreement between the simulated and measured neutron emission rate. An upper bound on the fast ion diffusivity of ~0.5-1 m2/sec is found in “MHD-free” discharges, based on the neutron emission, time rate of change of the neutron signal when a neutral beam is stepped, and reconstructed on-axis current density.
Plasma sources for spacecraft neutralization
NASA Technical Reports Server (NTRS)
Davis, V. A.; Katz, I.; Mandell, M. J.
1990-01-01
The principles of the operation of plasma sources for the neutralization of the surface of a spacecraft traveling in the presence of hot plasma are discussed with special attention given to the hollow-cathode-based plasma contactors. Techiques are developed that allow the calculation of the potentials and particle densities in the near environment of a hollow cathode plasma contactor in both the test tank and the LEO environment. The techniques and codes were validated by comparison of calculated and measured results.
NASA Astrophysics Data System (ADS)
Bruggeman, Peter; Degrez, Gérard; Delplancke, Marie-Paule; Gleizes, Alain
2011-05-01
The 11th High-Tech Plasma Processes Conference (HTPP) was held in Brussels, Belgium, 27 June-2 July, 2010. HTPP started as a thermal plasma conference and gradually expanded to include low-temperature plasmas. The conference was founded by Jacques Amouroux and Pierre Fauchais, and aims to bring together different scientific communities to facilitate contacts between science, technology and industry, providing a platform for the exploration of elementary processes and applications in and by plasmas. The first HTPP was held in Odeillo, France, in 1990. Since then it has been held every other year in different European cities: Paris, Aachen, Athens, Strasbourg, Saint-Petersburg, Patras and Brussels. The 11th HTPP conference was attended by 125 participants from 19 countries. The program involved 14 invited talks, 34 contributed talks, 72 posters and a software demonstration and hands-on session for plasma modelling. The 12th HTPP conference will be held 24-28 June 2012, in Bologna, Italy. A larger part of the contributions to the 11th HTPP has been published in the Journal of Physics: Conference Series (JPCS) volume 275, 2011. All invited speakers and other contributors, as selected by the Steering, Scientific and Organizing Committee, were invited to submit a paper based on their contributions for this special issue which is peer reviewed by the journal. Both this special issue and the JPCS volume aim to bring the 11th HTPP to a wider audience. The publications are a nice example of the broad topic range of the conference. The JPCS volume contains papers covering fundamental aspects on radiative processes of thermal plasmas, modelling of thermal arcs and non-thermal RF plasma jets, plasma diagnostics including flow and heat flux measurements of thermal plasmas, radical density measurements and laser-induced breakdown spectroscopy. The applications-oriented contributions of the JPCS volume include plasma spraying, synthesis of (nano-sized) materials, surface
Ralchenko, Yu.; Abdallah, J. Jr.; Colgan, J.; Fontes, C. J.; Foster, M.; Zhang, H. L.; Bar-Shalom, A.; Oreg, J.; Bauche, J.; Bauche-Arnoult, C.; Bowen, C.; Faussurier, G.; Chung, H.-K.; Hansen, S. B.; Lee, R. W.; Scott, H.; Gaufridy de Dortan, F. de; Poirier, M.; Golovkin, I.; Novikov, V.
2009-09-10
We present calculations of ionization balance and radiative power losses for tungsten in magnetic fusion plasmas. The simulations were performed within the framework of Non-Local Thermodynamic Equilibrium (NLTE) Code Comparison Workshops utilizing several independent collisional-radiative models. The calculations generally agree with each other; however, a clear disagreement with experimental ionization distributions at low temperatures 2 keV
NASA Astrophysics Data System (ADS)
Ghorbanzadeh, Atamalek; Pakmanesh, Nahid; Rastegari, Ali; Abdolghader, Pedram; Feizollah, Peyman; Siadati, Neda
2016-04-01
The performance of an atmospheric pressure pulsed carbon dioxide laser employing surface plasma preionization, produced on a specially patterned printed circuit board (PCB), is reported. The surface plasma is formed due to many tiny plasma channels produced in millimeter sized open circular gaps, made by lithography on one side of PCB. The preionizing plasma is mostly consisted of corona or glow stage and transition to spark one hardly occurs. This type of preionization allows a maximum of 220 J/l energy deposition into the main plasma, while up scaling is yet possible by more optimization of PCB and the pattern. The laser output energy of 1.2 J per pulse with overall efficiency of 7% has been obtained with gas mixture of He:CO2:N2=3:1:1. This type of surface plasma preionization is specifically appropriate for very large volumes and high pressures, where the conventional UV emitting preionizations like spark arrays or corona are not effective.
NASA Astrophysics Data System (ADS)
Adineh, V. R.; Coufal, O.; Bartlova, M.
2015-10-01
This work reports theoretical calculations of electrical discharge machining (EDM) radiative properties for mixture systems of N2-C, N2-Cu and N2-W arc plasmas, in the temperature range of 3000-10 000 K, and at 1 and 10 bar pressures. Radiative properties are computed for various plasma sizes as well as vapour proportions. Calculations consider line overlapping with spectrum coverage from 30 to 10 000 nm. Doppler, Natural, Van-der-Waals, Resonance and Stark broadening are taken into account as the line broadening mechanisms. Besides, continuum calculations consider bound-free and free-free emissions along with molecular bands radiation for selected molecular systems. Results show that contamination vapours of EDM electrode have strong influence on the amount of EDM plasma radiation to the surrounding environment. However, comparison of impurities from workpiece with electrode one indicates that Fe vapour has stronger impact on modifying the EDM arc plasma radiative properties, compared to the C, Cu and W species studied in this research.
NASA Astrophysics Data System (ADS)
Wu, Yi; Chen, Zhexin; Rong, Mingzhe; Cressault, Yann; Yang, Fei; Niu, Chunping; Sun, Hao
2016-10-01
As the first part of this series of papers, a new calculation method for composition and thermodynamic properties of 2-temperature plasma considering condensed species under local chemical equilibrium (LCE) and local phase equilibrium assumption is presented. The 2-T mass action law and chemical potential are used to determine the composition of multiphase system. The thermo-physical properties of CO2-CH4 mixture, which may be a possible substitution for SF6, are calculated by this method as an example. The influence of condensed graphite, non-LTE effect, mixture ratio and pressure on the thermo-physical properties has been discussed. The results will serve as reliable reference data for computational simulation of CO2-CH4 plasmas.
NASA Astrophysics Data System (ADS)
Niu, Chunping; Chen, Zhexin; Rong, Mingzhe; Wang, Chunlin; Wu, Yi; Yang, Fei; Wang, Xiaohua; Pang, Qingping
2016-10-01
The transport coefficients, namely thermal conductivity, viscosity and electrical conductivity, of CO2-CH4 mixture in and out of LTE are calculated in this paper. The calculation was based on local chemical equilibrium (LCE) and local phase equilibrium assumption. The 2-temperature composition results obtained with consideration of condensed phase in the previous paper (Part I) of this series were used in this calculation. The transport coefficients were calculated by classical Chapman-Enskog method simplified by Devoto. The results are presented for different temperatures (300-30 000 K), pressures (0.1-10 atm), non-equilibrium degrees (1-5), and CH4 molar proportions (0-100%). The influence of condensed graphite, non-LTE effect, mixture ratio and pressure on the composition and thermodynamic properties has been discussed. The results will serve as reliable reference data for computational simulation of CO2-CH4 plasmas.
NASA Astrophysics Data System (ADS)
Posuvailo, V. M.; Klapkiv, M. D.; Student, M. M.; Sirak, Y. Y.; Pokhmurska, H. V.
2017-03-01
The oxide ceramic coating with copper inclusions was synthesized by the method of plasma electrolytic oxidation (PEO). Calculations of the Gibbs energies of reactions between the plasma channel elements with inclusions of copper and copper oxide were carried out. Two methods of forming the oxide-ceramic coatings on aluminum base in electrolytic plasma with copper inclusions were established. The first method – consist in the introduction of copper into the aluminum matrix, the second - copper oxide. During the synthesis of oxide ceramic coatings plasma channel does not react with copper and copper oxide-ceramic included in the coating. In the second case is reduction of copper oxide in interaction with elements of the plasma channel. The content of oxide-ceramic layer was investigated by X-ray and X-ray microelement analysis. The inclusions of copper, CuAl2, Cu9Al4 in the oxide-ceramic coatings were found. It was established that in the spark plasma channels alongside with the oxidation reaction occurs also the reaction aluminothermic reduction of the metal that allows us to dope the oxide-ceramic coating by metal the isobaric-isothermal potential oxidation of which is less negative than the potential of the aluminum oxide.
NASA Astrophysics Data System (ADS)
Tanaka, M.; Yamamoto, K.; Tashiro, S.; Nakata, K.; Yamamoto, E.; Yamazaki, K.; Suzuki, K.; Murphy, A. B.; Lowke, J. J.
2010-11-01
A gas tungsten arc (GTA) was modelled taking into account the contamination of the plasma by metal vapour from the molten anode. The whole region of GTA atmosphere including the tungsten cathode, the arc plasma and the anode was treated using a unified numerical model. A viscosity approximation was used to express the diffusion coefficient in terms of viscosity of the shielding gas and metal vapour. The transient two-dimensional distributions of temperature, velocity of plasma flow and iron vapour concentration were predicted, together with the molten pool as a function of time for a 150 A arc current at atmospheric pressure, both for helium and argon gases. It was shown that the thermal plasma in the GTA was influenced by iron vapour from the molten pool surface and that the concentration of iron vapour in the plasma was dependent on the temperature of the molten pool. GTA on high sulfur stainless steel was calculated to discuss the differences between a low sulfur and a high sulfur stainless steel anode. Helium was selected as the shielding gas because a helium GTA produces more metal vapour than an argon GTA. In the GTA on a high sulfur stainless steel anode, iron vapour and current path were constricted. Radiative emission density in the GTA on high sulfur stainless steel was also concentrated in the centre area of the arc plasma together with the iron vapour although the temperature distributions were almost the same as that in the case of a low sulfur stainless steel anode.
NASA Astrophysics Data System (ADS)
Green, D. L.; Berry, L. A.; Jaeger, E. F.; Choi, M.
2008-11-01
In burning plasma experiments, the combination of neutral beam injection, high power electromagnetic heating and fusion products give rise to significant non-thermal ion populations. The resulting non-Maxwellian plasma affects ICRF wave propagation and heating. Self-consistent simulation of these effects has been achieved by an iterative coupling of a full-wave electromagnetic solver with a bounce-averaged Fokker-Planck (F-P) code under the zero banana width approximation. Investigating the effects of finite width particle orbits is possible by iterating with a Monte-Carlo calculation of the ion distribution function in place of the F-P code. Here we present progress towards coupling the all-orders global wave solver AORSA with the ORBIT-RF Monte-Carlo code. ORBIT-RF solves the Hamiltonian guiding center equations under coulomb collisions and ICRF quasi-linear (QL) heating taking the QL diffusion coefficients calculated from the AORSA wave fields as inputs. However, completing the self-consistent, time dependent calculation requires adapting the resulting Monte-Carlo particle list to a distribution function suitable for input to AORSA. Issues associated with calculating the differentiable bounce-averaged distribution function from discrete particle data will be discussed. E. F. Jaeger, et al., Phys. of Plasmas, 13, 056101-1, 2006
Goldenbaum, G.C.; Granneman, E.H.A.; Hartman, C.W.; Prono, D.S.; Taska, J.; Turner, W.C.
1982-08-10
Several types of radiation measurements were performed on the Beta II compact forms experiment. Among these are time integrated spectra ranging in wavelength from the vuv to the uv, time resolved bolometer measurements of radiation from the x-ray to the infrared, and time and wavelength resolved measurements of certain spectral lines. It is difficult to relate any one of these measurements to plasma parameters of interest such as temperature, density, or impurity content. In this report we compare the results of these, and other measurements with two simple models of the power balance in the plasma in order to estimate the effect of carbon and oxygen impurities on plasma lifetime.
NASA Astrophysics Data System (ADS)
Perlick, Volker; Tsupko, Oleg Yu.
2017-05-01
We consider light propagation in a nonmagnetized pressureless plasma around a Kerr black hole. We find the necessary and sufficient condition the plasma electron density has to satisfy to guarantee that the Hamilton-Jacobi equation for the light rays is separable, i.e., that a generalized Carter constant exists. For all cases where this condition is satisfied we determine the photon region; i.e., the region in the spacetime where spherical light rays exist. A spherical light ray is a light ray that stays on a sphere r =constant (in Boyer-Lindquist coordinates). Based on these results, we calculate the shadow of a Kerr black hole under the influence of a plasma that satisfies the separability condition. More precisely, we derive an analytical formula for the boundary curve of the shadow on the sky of an observer that is located anywhere in the domain of outer communication. Several examples are worked out.
NASA Astrophysics Data System (ADS)
Vinko, Sam
2014-10-01
An accurate description of the ionization potential depression (IPD) of ions in plasmas due to their interaction with the environment is a fundamental problem in plasma physics, playing a key role in determining the ionization balance, charge state distribution, opacity and plasma equation of state. Here I present the first experimental investigation of the IPD as a function of ionic charge state in a range of dense Mg, Al and Si plasmas, using the Linac Coherent Light Source X-ray free-electron laser. The measurements show significantly larger IPDs than are predicted by the most commonly used models, such as that of Stewart-Pyatt, or the ion-sphere model of Zimmerman-More. Instead, plasma simulations using finite-temperature density functional theory with excited-state projector augmented-wave potentials show excellent agreement with the experimental results and explain the stronger-than-expected continuum lowering through the electronic structure of the valence states in these strong-coupling conditions, which retain much of their atomic characteristics close to the ion core regions. These results have a profound impact on the understanding and modelling of plasmas over a wide range of warm- and hot-dense matter conditions.
Patacchini, Leonardo; Hutchinson, Ian H.
2008-07-11
The ion drag force on a spherical dust particle immersed in a flowing plasma with an external electric field is self-consistently calculated using the particle-in-cell code SCEPTIC in the entire range of charge-exchange collisionality. Our results, not based on questionable approximations, extend prior analytic calculations valid only in a few limiting regimes. Particular attention is given to the force direction, shown never to be directed opposite to the flow except in the continuum limit, where other forces are of a much stronger magnitude.
Stambulchik, E; Maron, Y
2013-05-01
We present an analytical method for the calculation of shapes of Stark-broadened spectral lines in plasmas, applicable to hydrogen and hydrogenlike transitions (including Rydberg ones) with Δn>1. The method is based on the recently suggested quasicontiguous approximation of the static Stark line shapes, while the dynamical effects are accounted for using the frequency-fluctuation-model approach. Comparisons with accurate computer simulations show excellent agreement.
Ristanović, D; Ristanović, D; Malesević, J; Milutinović, B
1983-01-01
Plasma kinetics of bromsulphalein (BSP) after a single injection into the bloodstream of the rat with total obstruction of the common bile duct was examined. The concentrations of BSP were determined colorimetrically. A monoexponential plus a general first-degree function in time with four unknown parameters was fitted. Two programs were developed for the Texas Instruments 59 programmable calculator to estimate the values of all the parameters by an iteration procedure. The programs executed at about twice normal speed.
2013-01-01
Point-of-injury use of reconstituted freeze dried plasma as a resuscitative fluid : A special report for prehospital trauma care Elon Glassberg, MD...Ramat Gan, Israel This special report describes the broader implications ofprehospital fluid resuscitation in the context of what is the first reported...case of point-of-injury use of reconstituted, lyophilized single-donor freeze dried plasma (FDP) as a re- suscitative fluid . The Israeli Defense Force
Potential and electron density calculated for freely expanding plasma by an electron beam
Ho, C. Y.; Tsai, Y. H.; Ma, C.; Wen, M. Y.
2011-07-01
This paper investigates the radial distributions of potential and electron density in free expansion plasma induced by an electron beam irradiating on the plate. The region of plasma production is assumed to be cylindrical, and the plasma expansion is assumed to be from a cylindrical source. Therefore, the one-dimensional model in cylindrical coordinates is employed in order to analyze the radial distributions of the potential and electron density. The Runge-Kutta method and the perturbation method are utilized in order to obtain the numerical and approximate solutions, respectively. The results reveal that the decrease in the initial ion energy makes most of the ions gather near the plasma production region and reduces the distribution of the average positive potential, electron, and ion density along the radial direction. The oscillation of steady-state plasma along the radial direction is also presented in this paper. The ions induce a larger amplitude of oscillation along the radial direction than do electrons because the electrons oscillate around slowly moving ions due to a far smaller electron mass than ion mass. The radial distributions of the positive potential and electron density predicted from this study are compared with the available experimental data.
Cucuianu, M; Rus, H G; Cristea, A; Niculescu, F; Bedeleanu, D; Poruţiu, D; Roman, S
1985-04-30
When compared to age-matched normal weight normolipidemic control subjects, plasma factor XIII, plasma fibronectin and serum cholinesterase levels were found to be markedly decreased in patients with decompensated cirrhosis of the liver, not significantly changed in hyperlipoproteinemia type IIa (heterozygous subjects) and increased in hypertriglyceridemic subjects (type IIb and IV) as well as in hyperlipidemic nephrotic patients. A possible accelerated hepatic synthesis of certain plasma proteins including factor XIII and fibronectin in patients with the nephrotic syndrome as well as in endogenous hypertriglyceridemia is envisaged. It is also considered that mural thrombi, richer in factor XIII and fibronectin, would be more resistant to fibrinolysis and more readily attached to subendothelial structures.
Transport calculations of chemically sputtered carbon near a plasma divertor surface
Brooks, J.N.
1992-01-01
The transport of chemically sputtered carbon near a tokamak divertor surface has been analyzed with the Monte Carlo code WBC. The code follows the motion of sputtered methane atoms and the resulting carbon and hydrocarbon derivatives. Ion transport due to the magnetic field, sheath electric field, and collisions with the plasma is computed. Redeposition fractions, impinging species type, charge state, and velocity have been analyzed. For plasma temperatures {ge} 10 eV, and for typical divertor plasma densities, local redeposition of chemically sputtered carbon approaches 100%. Redeposition fractions are lower ({approximately}80%) for lower temperatures and/or lower density. Physical sputtering of carbon due to redeposition of chemically sputtered material is low but a hydrocarbon reflection cascade due to redeposition may be high.
Radiation cooling and gain calculation for C VI 182 A line in C/Se plasma
Nam, C.H.; Valeo, E.; Suckewer, S.; Feldman, U.
1986-04-01
A model is developed which is capable of describing the evolution of gain resulting from both rapid radiative and expansion cooling of a recombining, freely expanding plasma. It is demonstrated for the particular case of a carbon/selenium plasma that the cooling rate which leads to optimal gain can be achieved by adjusting the admixture of an efficiently radiating material (selenium) in the gain medium (carbon). Comparison is made to a recent observation of gain in a recent NRL/Rochester experiment with carbon/selenium plasma for the n = 3 ..-->.. 2 transition in C VI occurring at 182 A. The predicted maximum gain is approx.10 cm/sup -1/, as compared to observation of 2 to 3 cm/sup -1/.
Calculating the radiation characteristics of accelerated electrons in laser-plasma interactions
Li, X. F.; Yu, Q.; Qu, J. F.; Kong, Q.; Gu, Y. J.; Ma, Y. Y.; Kawata, S.
2016-03-15
In this paper, we studied the characteristics of radiation emitted by electrons accelerated in a laser–plasma interaction by using the Lienard–Wiechert field. In the interaction of a laser pulse with a underdense plasma, electrons are accelerated by two mechanisms: direct laser acceleration (DLA) and laser wakefield acceleration (LWFA). At the beginning of the process, the DLA electrons emit most of the radiation, and the DLA electrons emit a much higher peak photon energy than the LWFA electrons. As the laser–plasma interaction progresses, the LWFA electrons become the major radiation emitter; however, even at this stage, the contribution from DLA electrons is significant, especially to the peak photon energy.
NASA Astrophysics Data System (ADS)
Jaeger, E. F.
2005-10-01
High-performance burning plasma devices such as ITER will contain significant concentrations of non-thermal plasma particles arising from fusion reactions, neutral beam injection, and wave-driven diffusion in velocity space. Initial studies in 1-D [1] and experimental results [2] show that non-thermal energetic ions can significantly alter wave propagation and absorption in the ion cyclotron range of frequencies. In addition, these ions can absorb power at high harmonics of the cyclotron frequency where conventional 2-D global-wave models are not valid. In this work, the all-orders, full-wave solver AORSA [3] is generalized to treat non-Maxwellian velocity distributions. Quasi-linear diffusion coefficients are derived directly from the global wave fields and used to calculate the energetic ion velocity distribution with the CQL3D Fokker-Planck code [4]. Alternately, the quasi-linear coefficients can be calculated numerically by integrating the Lorentz force equations along particle orbits. Self-consistency between the wave electric field and resonant ion distribution function is achieved by iterating between the full-wave and Fokker-Planck solutions.[1] R. J. Dumont, C. K. Phillips and D. N. Smithe, Phys. Plasmas 12, 042508 (2005).[2] A. L. Rosenberg, J. E. Menard, J. R. Wilson, et al., Phys. Plasmas 11, 2441(2004).[3] E. F. Jaeger, L. A. Berry, J. R. Myra, et al., Phys. Rev. Lett. 90, 195001-1 (2003).[4] R. W. Harvey and M. G. McCoy, in Proceedings of the IAEA Technical Committee Meeting on Advances in Simulation and Modeling of Thermonuclear Plasmas (IAEA, Montreal, 1992).
Acierno, Mark J; Mitchell, Mark A; Freeman, Diana M; Schuster, Patricia J; Guzman, David Sanchez-Migallon; Tully, Thomas N
2009-09-01
To determine plasma osmolality in healthy adult Hispaniolan Amazon parrots (Amazona ventralis) and validate osmolality equations in these parrots. 20 healthy adult Hispaniolan Amazon parrots. A blood sample (0.5 mL) was collected from the right jugular vein of each parrot and placed into a lithium heparin microtainer tube. Samples were centrifuged, and plasma was harvested and frozen at -30 degrees C. Samples were thawed, and plasma osmolality was measured in duplicate with a freezing-point depression osmometer. The mean value was calculated for the 2 osmolality measurements. Plasma osmolality values were normally distributed, with a mean +/- SD of 326.0 +/- 6.878 mOsm/kg. The equations (2 x [Na(+) + K(+)]) + (glucose/18), which resulted in bias of 2.3333 mOsm/kg and limits of agreement of -7.0940 to 11.7606 mOsm/kg, and (2 x [Na(+) + K(+)]) + (uric acid concentration/16.8) + (glucose concentration/18), which resulted in bias of 5.8117 mOsm/kg and limits of agreement of -14.6640 to 3.0406 mOsm/kg, yielded calculated values that were in good agreement with the measured osmolality. IV administration of large amounts of hypotonic fluids can have catastrophic consequences. Osmolality of the plasma from parrots in this study was significantly higher than that of commercially available prepackaged fluids. Therefore, such fluids should be used with caution in Hispaniolan Amazon parrots as well as other psittacines. Additional studies are needed to determine whether the estimation of osmolality has the same clinical value in psittacines as it does in other animals.
NASA Astrophysics Data System (ADS)
Dalimier, E.; Oks, E.
2017-01-01
Transport phenomena in plasmas, such as, e.g., resistivity, can be affected by electrostatic turbulence that frequently occurs in various kinds of laboratory and astrophysical plasmas. Transport phenomena are affected most significantly by a low-frequency electrostatic turbulence—such as, e.g., ion acoustic waves, also known as ionic sound—causing anomalous resistivity. In this case, for computing profiles of spectral lines, emitted by plasma ions, by any appropriate code for diagnostic purposes, it is necessary to calculate the distribution of the total quasistatic field. For a practically important situation, where the average turbulent field is much greater than the characteristic ion microfield, we develop a robust computational method valid for any appropriate distribution of the ion microfield at a charged point. We show that the correction to the Rayleigh distribution of the turbulent field is controlled by the behavior of the ion microfield distribution at large fields—in distinction to the opposite (and therefore, erroneous) result in the literature. We also obtain a universal analytical expression for the correction to the Rayleigh distribution based on the asymptotic of the ion microfield distribution at large fields at a charged point. By comparison with various known distributions of the ion microfield, we show that our asymptotic formula has a sufficiently high accuracy. Also exact computations are used to verify the high accuracy of the method. This robust approximate, but accurate method yields faster computational results than the exact calculations and therefore should be important for practical situations requiring simultaneous computations of a large number of spectral lineshapes (e.g., for calculating opacities)—especially for laser-produced plasmas.
NASA Astrophysics Data System (ADS)
Kim, Deok-Kyu; Kim, Inho
2004-10-01
We explain that the classical integral expression of the average electron-ion momentum transfer cross section is of limited applicability to dense plasmas without correcting the cutoff screening radius approximation, and that the Zollweg-Liebermann model appears practically useful to reproduce the experimental data with mathematical simplicity.
Kim, Deok-Kyu; Kim, Inho
2004-10-01
We explain that the classical integral expression of the average electron-ion momentum transfer cross section is of limited applicability to dense plasmas without correcting the cutoff screening radius approximation, and that the Zollweg-Liebermann model appears practically useful to reproduce the experimental data with mathematical simplicity.
UAH mathematical model of the variable polarity plasma ARC welding system calculation
NASA Technical Reports Server (NTRS)
Hung, R. J.
1994-01-01
Significant advantages of Variable Polarity Plasma Arc (VPPA) welding process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. A mathematical model is presented to analyze the VPPA welding process. Results of the mathematical model were compared with the experimental observation accomplished by the GDI team.
NASA Astrophysics Data System (ADS)
Karavaev, G. F.; Uspenskii, B. A.; Chuprikov, N. L.
1980-04-01
A numerical analysis is made of the threshold characteristics of the helical instability of a semiconductor plasma which fills a half-space; these are the threshold electric field, the threshold frequency of the oscillations, the optimal wave vector, and the optimal angle of propagation of a wave. The characteristic dependences for these quantities are presented and explained qualitatively.
NASA Technical Reports Server (NTRS)
Nonnast, J. H.; Chaky, R. C.; Armstrong, T. P.; Enoch, J.; Wiseman, G.
1980-01-01
A computer program is being developed to simulate the interaction of a plasma with a conducting disk partially covered by an insulator. Initial runs consider only charge sticking to the dielectric. Results indicate that the current density drawn by the hole in the dielectric increases approximately linearly with voltage for conductor voltages between 5 volts and 250 volts.
NASA Astrophysics Data System (ADS)
Benedict, Lorin X.; Surh, Michael P.; Khairallah, Saad A.; Castor, John I.; Whitley, Heather D.; Richards, David F.; Glosli, James N.; Murillo, Michael S.; Graziani, Frank R.
2011-10-01
We present classical molecular dynamics (MD) calculations of temperature relaxation in hydrogen, Ar-doped hydrogen, and SF6 plasmas in which the two-particle interactions are represented by statistical potentials of the Dunn-Broyles and modified Kelbg forms. Using a multi-species generalized Lenard-Balescu theory in which the full frequency and wave-vector dependent dielectric response is included, we show that deviations of our hydrogen MD results from the weak-coupling theories such as Landau-Spitzer are due in large part to the use of the statistical potentials which approximate, in a classical way, the effects of quantum diffraction. Classical MD with Kelbg potentials is shown to be better at reproducing intermediate-to-weak-coupling results of true quantum-Coulomb plasmas, but it is also shown that MD with both types of statistical potential yield the correct quantum result in the limit of infinitesimal plasma coupling. Effects of dynamical screening in multi-component plasmas are also discussed.
Numerical and Analytical Calculation of Bernstein Resonances in a Non-Uniform Cylindrical Plasma
NASA Astrophysics Data System (ADS)
Walsh, D. K.; Dubin, D. H. E.
2016-10-01
This poster presents theory and numerical predictions of electrostatic Bernstein modes in a cylindrical non-neutral plasma column with multiple ion species. These modes propagate radially across the column until they are reflected when their frequency matches the local upper hybrid frequency, setting up an internal normal mode on the column, and also mode-coupling to the electrostatic surface cyclotron wave (which allows the normal mode to be excited and observed using external electrodes). Using our linear Vlasov code discussed last year, we present several numerical results at various magnetic fields, eilθ-dependencies, and plasma profiles in order to make quantitative predictions of future cyclotron wave experiments. These results are compared to the semi-analytic WKB theory in order to determine under what conditions Bernstein waves are measurable at the wall. Supported by NSF Grant PHY-1414570, and DOE Grants DE-SC0002451.
Model calculations for the explosive generator-driven dense plasma focus
Brownell, J.; Landshoff, R.
1982-02-01
A models was developed to aid in the design and interpretation of explosive generator-driven dense plasma focus experiments. Several models were investigated, but the one presented here employs a plane sheath propagating along the barrel of a Mather-type gun, entraining a constant fraction of the swept-up gas and carrying the return current between the electrodes. The motion of the sheath is determined from the momentum equation using the integrated magnetic force on the sheath. The solutions are obtained both numerically and by an approximate analytic procedure, and the performance of the system has been determined as a funtion of the switching time when the generator is connected to the dense plasma focus.
Garanin, S. F. Kravets, E. M.
2012-11-15
The semiclassical approach to determine the Fourier components of the electron dipole moment disregarding polarization (noninteracting electron model) is used for analyzing ion oscillator strengths and determining the radiation properties of plasmas consisting of multiply charged ions of heavy elements. The oscillator strength distribution df/d{omega} (proportional to the photoabsorption cross section) is calculated as a function of the degree of ionization and self-similar frequency {Omega} = {omega}/Z. It is found that for low degrees of ionization, function df/d{omega} for an ion is close to function df/d{omega} for a neutral atom; upon an increase in the degree of ionization, regions are formed in which df/d{omega} = 0 (transparency windows) and the photoabsorption cross section for high degrees of ionization differs from zero only in small frequency ranges. The resultant distribution of the ion oscillator strengths is used for calculating the polarizability of ions as a function of frequency and the cross section of radiation scattering on ions. For a gold plasma, the absorbance and opacity (both spectral and averaged according to Rosseland and Planck) are calculated. The results of computing the paths and absorption coefficients coincide in order of magnitude with the available data. The effect of scattering on the Rosseland path is estimated.
NASA Astrophysics Data System (ADS)
Coates, A. J.; Wellbrock, A.; Yamauchi, M.
2015-12-01
Within our solar system, the planets, moons, comets and asteroids all have plasma interactions. The interaction depends on the nature of the object, particularly the presence of an atmosphere and a magnetic field. Even the size of the object matters through the finite gyroradius effect and the scale height of cold ions of exospheric origin. It also depends on the upstream conditions, including position within the solar wind or the presence within a planetary magnetosphere. Soon after ESA's Rosetta reached comet Churyumov-Gerasimenko, NASA's Maven and ISRO's Mars Orbiter Mission (MOM) reached Mars, and ESA's Venus Express mission was completed, this issue explores our understanding of plasma interactions with comets, Mars, Venus, and moons in the solar system. We explore the processes which characterise the interactions, such as ion pickup and field draping, and their effects such as plasma escape. Papers are based on data from current and recent space missions, modelling and theory, as we explore our local part of the 'plasma universe'.
NASA Astrophysics Data System (ADS)
Shukurov, Anvar; Sokoloff, Dmitry; Schekochihin, Alexander
2015-08-01
This issue commemorates an outstanding scientist of the twentieth century, Yakov Borisovich Zeldovich, in connection with the centenary of his birth (8 March 1914), with a collection of reviews and research articles broadly related to large-scale random phenomena in astrophysical plasmas.
Snoeys, Jan; Beumont, Maria; Monshouwer, Mario; Ouwerkerk-Mahadevan, Sivi
2016-11-29
The disposition of simeprevir (SMV) in humans is characterised by cytochrome P450 3A4 metabolism and hepatic uptake by organic anion transporting polypeptide 1B1/3 (OATP1B1/3). This study was designed to investigate SMV plasma and liver exposure upon oral administration in subjects infected with hepatitis C virus (HCV), in subjects of Japanese or Chinese origin, subjects with organ impairment and subjects with OATP genetic polymorphisms, using physiologically based pharmacokinetic modelling. Simulations showed that compared with healthy Caucasian subjects, SMV plasma exposure was 2.4-, 1.7-, 2.2- and 2.0-fold higher, respectively, in HCV-infected Caucasian subjects, in healthy Japanese, healthy Chinese and subjects with severe renal impairment. Further simulations showed that compared with HCV-infected Caucasian subjects, SMV plasma exposure was 1.6-fold higher in HCV-infected Japanese subjects. In subjects with OATP1B1 genetic polymorphisms, no noteworthy changes in SMV pharmacokinetics were observed. Simulations suggested that liver concentrations in Caucasians with HCV are 18 times higher than plasma concentrations.
R-matrix calculations for electron impact excitation and their application in astrophysical plasmas
NASA Astrophysics Data System (ADS)
Liang, G. Y.; Badnell, N. R.; Del Zanna, G.; Mason, H. E.; Storey, P. J.; Zhao, G.
2012-11-01
The large number of high-resolution spectra routinely recorded in the astrophysical and fusion communities leads to the need for an extensive set of accurate baseline atomic data. The advantages of the intermediate-coupling frame transformation (ICFT) R-matrix method make it feasible to provide excitation data along iso-electronic sequences (Z <= 36) at the high level of accuracy afforded by the R-matrix method. The resultant data helps to overcome the longstanding shortcomings in X-ray and EUV astronomy. This is one of the key goals of the UK Atomic Processes for Astrophysical Plasmas (APAP) network.
Hans, P; Brichant, J F; Dewandre, P Y; Born, J D; Lamy, M
1999-04-01
The effects of two calculated plasma sufentanil (SUF) concentrations on the hemodynamic and bispectral index (BIS) responses to Mayfield head holder (MH) application were studied in 20 patients scheduled for intracranial surgery. Premedication consisted of hydroxyzine, alprazolam, and atropine given orally 1 hour before surgery. Anesthesia was provided with propofol (PPF) and SUF using a target-controlled infusion device. Patients were randomly assigned to one of two groups according to calculated plasma concentrations: 3 microg/mL(-1) of PPF and 0.5 ng/mL(-1) of SUF in group I (GI) and 3 microg/mL(-1) of PPF and 1 ng/mL(-1) of SUF in group II (GII). The MH was fixed 33.0+/-6.6 minutes (mean +/- SD) after induction. Systolic (SAP), diastolic (DAP), and mean arterial pressure (MAP) as well as heart rate (HR) and BIS were recorded 1 minute before pinning (baseline) as well as 1 minute (P1), 2 minutes (P2), and 3 minutes (P3) after pinning. Multivariate repeat-measured analyses of variance were applied to the baseline-subtracted measurements of hemodynamic and BIS values. Groups were compared using the Student's t test, and P < .05 was considered to be statistically significant. Patients' characteristics, baseline hemodynamic values, and BIS values were similar in both groups. A significant overall time effect was observed for all variables, but no significant overall SUF effect was detected. Increases in SAP, MAP, DAP, and HR did not differ significantly between groups. The increase in hemodynamic variables did not exceed 20% of baseline value in either group. In contrast, at P1, the increase in BIS over the baseline value was significantly higher in GI (15.0+/-7.9) than in GII (6.7+/-6.5). In conclusion, MH application was associated with a significant, although not clinically relevant, increase in hemodynamic variables whatever the calculated plasma SUF concentration (0.5 or 1.0 ng/mL(-1)). In contrast, the increase in BIS observed at pinning was significantly
NASA Astrophysics Data System (ADS)
Frolova, A. A.; Khishchenko, K. V.; Charakhch'yan, A. A.
2016-03-01
Integral formulas for the three-dimensional case that give the plasma heating rate per unit volume are obtained using the track method and by integrating the well-known Cauchy problem for the steady-state homogeneous kinetic equation in the Fokker-Planck approximation in the absence of diffusion of the distribution function in the velocity space and under the condition that the velocity of the produced particles is independent on the direction of their escape. It is shown that both integral formulas are equivalent and, in the case of space homogeneous coefficients, turn into the model of local plasma heating away from the domain boundary. In addition to the known direct track method, the inverse method based on the approximation of the integral formula is developed. It is shown that the accuracy of the direct method is significantly decreased in the vicinity of the symmetry axis for not very fine angular grids. In the inverse method, the accuracy is not lost. It is shown that the computational cost of the inverse method can be significantly reduced without the considerable reduction of the computation accuracy.
Wu, D; He, X T; Yu, W; Fritzsche, S
2017-02-01
A physical model based on a Monte Carlo approach is proposed to calculate the ionization dynamics of hot-solid-density plasmas within particle-in-cell (PIC) simulations, and where the impact (collision) ionization (CI), electron-ion recombination (RE), and ionization potential depression (IPD) by surrounding plasmas are taken into consideration self-consistently. When compared with other models, which are applied in the literature for plasmas near thermal equilibrium, the temporal relaxation of ionization dynamics can also be simulated by the proposed model. Besides, this model is general and can be applied for both single elements and alloys with quite different compositions. The proposed model is implemented into a PIC code, with (final) ionization equilibriums sustained by competitions between CI and its inverse process (i.e., RE). Comparisons between the full model and model without IPD or RE are performed. Our results indicate that for bulk aluminium at temperature of 1 to 1000 eV, (i) the averaged ionization degree increases by including IPD; while (ii) the averaged ionization degree is significantly over estimated when the RE is neglected. A direct comparison from the PIC code is made with the existing models for the dependence of averaged ionization degree on thermal equilibrium temperatures and shows good agreements with that generated from Saha-Boltzmann model and/or FLYCHK code.
NASA Astrophysics Data System (ADS)
Wu, D.; He, X. T.; Yu, W.; Fritzsche, S.
2017-02-01
A physical model based on a Monte Carlo approach is proposed to calculate the ionization dynamics of hot-solid-density plasmas within particle-in-cell (PIC) simulations, and where the impact (collision) ionization (CI), electron-ion recombination (RE), and ionization potential depression (IPD) by surrounding plasmas are taken into consideration self-consistently. When compared with other models, which are applied in the literature for plasmas near thermal equilibrium, the temporal relaxation of ionization dynamics can also be simulated by the proposed model. Besides, this model is general and can be applied for both single elements and alloys with quite different compositions. The proposed model is implemented into a PIC code, with (final) ionization equilibriums sustained by competitions between CI and its inverse process (i.e., RE). Comparisons between the full model and model without IPD or RE are performed. Our results indicate that for bulk aluminium at temperature of 1 to 1000 eV, (i) the averaged ionization degree increases by including IPD; while (ii) the averaged ionization degree is significantly over estimated when the RE is neglected. A direct comparison from the PIC code is made with the existing models for the dependence of averaged ionization degree on thermal equilibrium temperatures and shows good agreements with that generated from Saha-Boltzmann model and/or FLYCHK code.
NASA Astrophysics Data System (ADS)
Benedict, Lorin X.; Surh, Michael P.; Castor, John I.; Khairallah, Saad A.; Whitley, Heather D.; Richards, David F.; Glosli, James N.; Murillo, Michael S.; Scullard, Christian R.; Grabowski, Paul E.; Michta, David; Graziani, Frank R.
2012-10-01
We study the problem of electron-ion temperature equilibration in plasmas. We consider pure H at various densities and temperatures and Ar-doped H at temperatures high enough so that the Ar is fully ionized. Two theoretical approaches are used: classical molecular dynamics (MD) with statistical two-body potentials and a generalized Lenard-Balescu (GLB) theory capable of treating multicomponent weakly coupled plasmas. The GLB is used in two modes: (1) with the quantum dielectric response in the random-phase approximation (RPA) together with the pure Coulomb interaction and (2) with the classical (ℏ→0) dielectric response (both with and without local-field corrections) together with the statistical potentials. We find that the MD results are described very well by classical GLB including the statistical potentials and without local-field corrections (RPA only); worse agreement is found when static local-field effects are included, in contradiction to the classical pure-Coulomb case with like charges. The results of the various approaches are all in excellent agreement with pure-Coulomb quantum GLB when the temperature is high enough. In addition, we show that classical calculations with statistical potentials derived from the exact quantum two-body density matrix produce results in far better agreement with pure-Coulomb quantum GLB than classical calculations performed with older existing statistical potentials.
Convergence of Chapman-Enskog calculation of transport coefficients of magnetized argon plasma
Bruno, D.; Catalfamo, C.; Laricchiuta, A.; Giordano, D.; Capitelli, M.
2006-07-15
Convergence properties of the Chapman-Enskog method in the presence of a magnetic field for the calculation of the transport properties of nonequilibrium partially ionized argon have been studied emphasizing the role of the different collision integrals. In particular, the Ramsauer minimum of electron-argon cross sections affects the convergence of the Chapman-Enskog method at low temperature, while Coulomb collisions affect the results at higher temperatures. The presence of an applied magnetic field mitigates the slow convergence for the components affected by the field.
Shi, Zongqian; Wang, Kun; Li, Yao; Shi, Yuanjie; Wu, Jian; Jia, Shenli
2014-03-15
The electron chemical potential and ion charge state (average ion charge and ion distribution) are important parameters in calculating plasma conductivity in electrical explosion of metal wire. In this paper, the calculating method of electron chemical potential and ion charge state is discussed at first. For the calculation of electron chemical potential, the ideal free electron gas model and Thomas-Fermi model are compared and analyzed in terms of the coupling constant of plasma. The Thomas-Fermi ionization model, which is used to calculate ion charge state, is compared with the method based on Saha equation. Furthermore, the influence of electron degenerated energy levels and ion excited states in Saha equation on the ion charge state is also analyzed. Then the influence of different calculating methods of electron chemical potential and ion charge state on plasma conductivity is discussed by applying them in the Lee-More conductivity model.
NASA Astrophysics Data System (ADS)
Dhamale, G. D.; Mathe, V. L.; Bhoraskar, S. V.; Sahasrabudhe, S. N.; Ghorui, S.
2015-10-01
Synthesis of yttrium oxide nanoparticles in a specially designed radio frequency thermal plasma reactor is reported. Good crystallinity, narrow size distribution, low defect state concentration, high purity, good production rate, single-step synthesis, and simultaneous formation of nanocrystalline monoclinic and cubic phases are some of the interesting features observed. Synthesized particles are characterized through X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, thermo-luminescence (TL), and Brunauer-Emmett-Teller surface area analysis. Polymorphism of the nanocrystalline yttria is addressed in detail. Synthesis mechanism is explored through in-situ emission spectroscopy. Post-synthesis environmental effects and possible methods to eliminate the undesired phases are probed. Defect states are investigated through the study of TL spectra.
Ab initio calculation of H+He{sup +} charge-transfer cross sections for plasma physics
Loreau, J.; Vaeck, N.; Lauvergnat, D.; Desouter-Lecomte, M.
2010-07-15
The charge-transfer in low-energy (0.25 to 150 eV/amu) H(nl)+He{sup +}(1s) collisions is investigated using a quasimolecular approach for the n=2,3 as well as the first two n=4 singlet states. The diabatic potential energy curves of the HeH{sup +} molecular ion are obtained from the adiabatic potential energy curves and the nonadiabatic radial coupling matrix elements using a two-by-two diabatization method, and a time-dependent wave-packet approach is used to calculate the state-to-state cross sections. We find a strong dependence of the charge-transfer cross section on the principal and orbital quantum numbers n and l of the initial or final state. We estimate the effect of the nonadiabatic rotational couplings, which is found to be important even at energies below 1 eV/amu. However, the effect is small on the total cross sections at energies below 10 eV/amu. We observe that to calculate charge-transfer cross sections in an n manifold, it is only necessary to include states with n{sup '{<=}}n, and we discuss the limitations of our approach as the number of states increases.
Allen, Steve L.; Davidson, Ronald C.
2011-05-15
We present in this Special Issue of Physics of Plasmas the review, tutorial, and invited papers of the 2010 Annual Meeting of the American Physical Society's (APS) Division of Plasma Physics. This was the 52nd year of this meeting, and it was held in Chicago, Illinois on 8-12 November 2010. The meeting program was made up of over 100 review, tutorial, and invited oral presentations, and a significant fraction of these speakers prepared manuscripts which were peer-reviewed and are contained in this Special Issue.
NASA Astrophysics Data System (ADS)
Rubinkovskiy, N. A.; Zholnin, A. G.; Grigoryev, E. G.
2017-07-01
The research provides modeling of spark-plasma sintering process of aluminum oxide, specifically the distribution of temperature fields over the sample volume and mold at various stages of heating. Calculation was based on the experimental data on the measurement of temperature on the surface of the mold, inside the mold cavity and in its various internal parts including punches (diameter of 15 mm), in the absence of insulation felt. Experiments established that the main source of heat emission at temperatures less than 1300°C to 1400 °C is contact resistance at the borders of the punches and the matrix molds. Then heat emission zone moves towards the punches. Based on the received data, the temperature and electric parameters were selected for the materials used for the press mold, providing a good agreement between the observed and calculated distribution patterns at different temperatures. Obtained parameters were used in calculations of temperature fields in the press molds with insulation felt and for the press molds with diameter of 15 mm and 10 mm for the production of tablets as well as glazing beads.
Pham, Huy P; Müller, Marcella C; Williams, Lance A; Juffermans, Nicole P
2016-04-01
Plasma transfusion is often used prophylactically in patients with coagulopathy. However, the doses transfused may not be adequate to normalize hemostatic tests, which are commonly used as surrogate markers in practice. Currently, there is no reliable way to predict the posttransfusion international normalized ratio (INR) after plasma transfusion. Therefore, our aim was to develop and validate a formula that can reliably estimate post-plasma transfusion INR. A compartmental model was developed using demographic (sex, height, weight) and laboratory variables (hematocrit [Hct], INRinitial , and plasma volume transfused). The formula was validated using a data set from a multicenter trial conducted between May 2010 and June 2013 in critically ill, nonbleeding patients with coagulopathy, receiving prophylactic plasma transfusions. INR was measured just before and immediately after plasma transfusion. Initial plasma volume is calculated using the patient's Hct and blood volume (derived from Nadler's formula). The estimated immediate posttransfusion INR is then calculated as [Formula: see text] There was a significant agreement between the model predictions and the actual INR measurements after transfusion. A total of 83% of the predictions were within the acceptable range of variation. Furthermore, there was no proportional difference or systemic bias between the predictions and the actual INR measurements. This mathematical formula estimates posttransfusion INR after a certain volume of plasma transfusion with a good predictive ability. This formula, which only requires basic demographic and laboratory variables, may help the physicians to determine the volume of plasma required for a specific target INR in stable, nonbleeding patients. © 2015 AABB.
Simulation calculation of ion-induced sputtering yields for plasma-irradiated solid surfaces
NASA Astrophysics Data System (ADS)
Yamamura, Y.; Kawamura, T.
1990-12-01
A computer code ACAT, is used to evaluate the self-sputtering of graphite by carbon ions, taking into account finite temperature effect, the boundary sheath potential and the angle δ between the magnetic field vector and the normal to the surface. These yields are calculated for many initial energies and angles — which obey the shifted Maxwellian distribution — using the Monte Carlo random number technique and then averaged. It is found that for the precise understandings of sputtering thresholds and sputtering yields we should use the distributed ion sources such as the shifted Maxwellian as the ion source, not the average angles and average energies of the distributed ion source, because both the energy dependences of the near threshold sputtering and the bombarding angle dependence of the grazing angle sputtering are very strong. The influences of Ti, of the temperature ratio Ti/ Te and δ are also discussed. The sputtering yield becomes larger than unity for Te > 100 eV, when Ti/ Te > 5. This is a very severe problem for erosion of divertor plates. It means that we need a more precise knowledge of ion temperature on the operating conditions.
Shurygin, R. V.
2012-02-15
A one-dimensional evolution equation for the angle-averaged poloidal momentum of the tokamak plasma is derived in the framework of reduced magnetohydrodynamics with allowance for density inhomogeneity and diamagnetic drift of ions. In addition to fluctuations of the E Multiplication-Sign B drift velocity, the resulting turbulent Reynolds stress tensor includes fluctuations of the ion density and ion pressure, as well as turbulent radial fluxes of particles and heat. It is demonstrated numerically by using a particular example that the poloidal velocity calculated using the refined one-dimensional evolution equation differs substantially from that provided by the simplified model. When passing to the new model, both the turbulent Reynolds force and the Stringer-Winsor force increase, which leads to an increase in the amplitude of the ion poloidal velocity. This, in turn, leads to a decrease in turbulent fluxes of particles and heat due to the effect of shear decorrelation.
NASA Astrophysics Data System (ADS)
Hamilton, James R.; Tennyson, Jonathan; Huang, Shuo; Kushner, Mark J.
2017-06-01
Electron impact cross sections sets are constructed for the nitrogen trifluoride, nitrogen difluoride and nitrogen monofluoride molecules. These cross sections are based on ab initio R-matrix calculations augmented by other procedures. Cross sections are presented for elastic collisions, momentum transfer, dissociative electron attachment, electron impact dissociation, ionisation and dissociative ionisation. For NF process occurring via the metastable a {}1{{Δ }} and b {}1{{{Σ }}}+ states are also considered. A semi-empirical method of estimating the products of electron impact ionisation is proposed and tested for ammonia. The cross sections are extended to high energy where appropriate. The cross section set constructed is tested in a global model simulation of a low pressure, inductively coupled plasma based on a Ar/NF3/O2 initial gas mixture.
B.C. Lyons, S.C. Jardin, and J.J. Ramos
2012-06-28
A new code, the Neoclassical Ion-Electron Solver (NIES), has been written to solve for stationary, axisymmetric distribution functions (f ) in the conventional banana regime for both ions and elec trons using a set of drift-kinetic equations (DKEs) with linearized Fokker-Planck-Landau collision operators. Solvability conditions on the DKEs determine the relevant non-adiabatic pieces of f (called h ). We work in a 4D phase space in which Ψ defines a flux surface, θ is the poloidal angle, v is the total velocity referenced to the mean flow velocity, and λ is the dimensionless magnetic moment parameter. We expand h in finite elements in both v and λ . The Rosenbluth potentials, φ and ψ, which define the integral part of the collision operator, are expanded in Legendre series in cos χ , where χ is the pitch angle, Fourier series in cos θ , and finite elements in v . At each ψ , we solve a block tridiagonal system for hi (independent of fe ), then solve another block tridiagonal system for he (dependent on fi ). We demonstrate that such a formulation can be accurately and efficiently solved. NIES is coupled to the MHD equilibrium code JSOLVER [J. DeLucia, et al., J. Comput. Phys. 37 , pp 183-204 (1980).] allowing us to work with realistic magnetic geometries. The bootstrap current is calculated as a simple moment of the distribution function. Results are benchmarked against the Sauter analytic formulas and can be used as a kinetic closure for an MHD code (e.g., M3D-C1 [S.C. Jardin, et al ., Computational Science & Discovery, 4 (2012).]).
Lyons, B. C.; Jardin, S. C.; Ramos, J. J.
2012-08-15
A new code, the Neoclassical Ion-Electron Solver (NIES), has been written to solve for stationary, axisymmetric distribution functions (f) in the conventional banana regime for both ions and electrons using a set of drift-kinetic equations (DKEs) with linearized Fokker-Planck-Landau collision operators. Solvability conditions on the DKEs determine the relevant non-adiabatic pieces of f (called h). We work in a 4D phase space in which {psi} defines a flux surface, {theta} is the poloidal angle, v is the magnitude of the velocity referenced to the mean flow velocity, and {lambda} is the dimensionless magnetic moment parameter. We expand h in finite elements in both v and {lambda}. The Rosenbluth potentials, {Phi} and {Psi}, which define the integral part of the collision operator, are expanded in Legendre series in cos{chi}, where {chi} is the pitch angle, Fourier series in cos{theta}, and finite elements in v. At each {psi}, we solve a block tridiagonal system for h{sub i} (independent of f{sub e}), then solve another block tridiagonal system for h{sub e} (dependent on f{sub i}). We demonstrate that such a formulation can be accurately and efficiently solved. NIES is coupled to the MHD equilibrium code JSOLVER [J. DeLucia et al., J. Comput. Phys. 37, 183-204 (1980)] allowing us to work with realistic magnetic geometries. The bootstrap current is calculated as a simple moment of the distribution function. Results are benchmarked against the Sauter analytic formulas and can be used as a kinetic closure for an MHD code (e.g., M3D-C{sup 1}[S. C. Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)]).
NASA Astrophysics Data System (ADS)
Lyons, B. C.; Jardin, S. C.; Ramos, J. J.
2012-08-01
A new code, the Neoclassical Ion-Electron Solver (NIES), has been written to solve for stationary, axisymmetric distribution functions (f) in the conventional banana regime for both ions and electrons using a set of drift-kinetic equations (DKEs) with linearized Fokker-Planck-Landau collision operators. Solvability conditions on the DKEs determine the relevant non-adiabatic pieces of f (called h). We work in a 4D phase space in which ψ defines a flux surface, θ is the poloidal angle, v is the magnitude of the velocity referenced to the mean flow velocity, and λ is the dimensionless magnetic moment parameter. We expand h in finite elements in both v and λ. The Rosenbluth potentials, Φ and Ψ, which define the integral part of the collision operator, are expanded in Legendre series in cosχ, where χ is the pitch angle, Fourier series in cosθ, and finite elements in v. At each ψ, we solve a block tridiagonal system for hi (independent of fe), then solve another block tridiagonal system for he (dependent on fi). We demonstrate that such a formulation can be accurately and efficiently solved. NIES is coupled to the MHD equilibrium code JSOLVER [J. DeLucia et al., J. Comput. Phys. 37, 183-204 (1980)] allowing us to work with realistic magnetic geometries. The bootstrap current is calculated as a simple moment of the distribution function. Results are benchmarked against the Sauter analytic formulas and can be used as a kinetic closure for an MHD code (e.g., M3D -C1 [S. C. Jardin et al., Comput. Sci. Discovery 5, 014002 (2012)]).
Gotow, T
1984-06-01
Astrocytic membranes contacting the basal lamina are found to be less affected by filipin than subjacent lateral membranes. An abrupt change in density of lesions induced by filipin creates a border between subpial and lateral membranes at the glia limitans. This means that orthogonal array-crowded membranes may contain relatively less cholesterol than other astrocytic membrane domains. Another possible explanation for filipin resistance is also considered in relation to aggregated intramembrane particles of orthogonal arrays and/or membrane-associated filamentous elements including the basal lamina. The polygonal particle junction between astrocytic processes located just below the subpial membrane is strongly resistant to the action of filipin. Both membrane-associated enzymes, i.e. alkaline phosphatase (AlkPase) and Na+,K+-ATPase are commonly detected only in perivascular astrocytic membranes, and not in subpial membranes, suggesting a regional differentiation in function of astrocytic membranes. There are variations in the reactive deposits particularly of those for Na+,K+-ATPase. It is apparent that the distribution polarity of orthogonal arrays is not connected with that of either AlkPase or Na+,K+-ATPase. Judging from the relative resistance to filipin, however, astrocytes throughout the C.N.S., having domains specialized with orthogonal arrays, may possess a unique stabilizing mechanism for their own membranes contacting the basal lamina.
NASA Astrophysics Data System (ADS)
Itoh, K.; Wilson, H. R.
2010-05-01
The 4th IAEA technical meeting (TM) on the Theory of Plasma Instabilities was held in Kyoto, May 18th--20th 2009, following the first (Seeon), second (Trieste) and third (York) meetings in this series. This IAEA-TM was motivated by the recent advances in theoretical methodology, the rapid progress in observations of laboratory and astrophysical plasmas and the evolution of fusion research as we approach the ITER era. The international advisory committee (IAC) and local organizing committee (LOC), the members of which are listed below, collaborated to define the scope and the content of the scientific programme. Young scientists were actively encouraged to participate in this TM to help stimulate their future research careers and raise their international profiles. Through these young scientists, the IAEA-TM planned to identify the future directions of research. About 90 researchers, from 13 countries and the IAEA, participated in this IAEA-TM, with 72 scientific presentations. The talks and posters generated enthusiastic discussions, contributing to the vibrancy of the meeting. This special issue of Nuclear Fusion consists of a cluster of papers, reporting some of the main contributions to the IAEA-TM. The articles in this cluster are representative of the scientific width of presentations at the meeting, spanning topics from micro-turbulence to large-scale MHD dynamics and from transport to detailed analysis of diagnostics. They demonstrate the quality and depth of the research presented at the conference. List of IAC (alphabetical order): B. Breizman (USA), S. Guenter (Germany), T. S. Hahm (USA), K. Itoh (Japan, Chair of 2009), Ya. I. Kolesnichenko (Ukraine), A. G. Peeters (UK), H. Wilson (UK) List of LOC (alphabetical order): A. Fukuyama, R. Horiuchi, S.-I. Itoh, N. Kasuya, Y. Kishimoto (co-chair), K. Kusano, J. Li, K. Mima, S. Murakami, H. Naitou, N. Nakajima, Y. Nakamura, H. Ohtani, S. Okamura, T. Ozeki, S. Sudo (co-chair), H. Sugama, Y. Todo, S. Tokuda, S
Wickham, Fred; Burniston, Maria T; Xirouchakis, Elias; Theocharidou, Eleni; Wesolowski, Carl A; Hilson, Andrew J W; Burroughs, Andrew K
2013-11-01
The aim of this study was to identify a practical sampling regimen and calculation method that could be used to measure the glomerular filtration rate in patients with ascites using plasma sampling. Thirteen potential liver transplant patients with cirrhosis and ascites were injected with Cr-51 ethylenediaminetetraacetic acid, and plasma samples were obtained at up to 16 time points for each patient. Reference clearance values were calculated using the area under the plasma clearance curve, which was calculated using all the available data points. Clearance calculations were then performed using three and four data points from each patient and three different calculation methods to identify a sampling regimen and calculation method that yielded good agreement with the reference values. The reference clearances ranged from 6 to 80 ml/min. Sampling at 2, 4, 8 and 24 h and calculation of the area under the plasma clearance curve using a log-linear trapezoidal rule with extrapolation to zero and infinity yielded a relative root mean square difference from the reference of less than 7%. This method for measuring glomerular filtration rate in patients with cirrhosis and ascites was found to be more accurate than the slope-intercept technique and is a practical alternative to urine collection.
NASA Astrophysics Data System (ADS)
Mandrekas, John
2004-08-01
GTNEUT is a two-dimensional code for the calculation of the transport of neutral particles in fusion plasmas. It is based on the Transmission and Escape Probabilities (TEP) method and can be considered a computationally efficient alternative to traditional Monte Carlo methods. The code has been benchmarked extensively against Monte Carlo and has been used to model the distribution of neutrals in fusion experiments. Program summaryTitle of program: GTNEUT Catalogue identifier: ADTX Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTX Computer for which the program is designed and others on which it has been tested: The program was developed on a SUN Ultra 10 workstation and has been tested on other Unix workstations and PCs. Operating systems or monitors under which the program has been tested: Solaris 8, 9, HP-UX 11i, Linux Red Hat v8.0, Windows NT/2000/XP. Programming language used: Fortran 77 Memory required to execute with typical data: 6 219 388 bytes No. of bits in a word: 32 No. of processors used: 1 Has the code been vectorized or parallelized?: No No. of bytes in distributed program, including test data, etc.: 300 709 No. of lines in distributed program, including test data, etc.: 17 365 Distribution format: compressed tar gzip file Keywords: Neutral transport in plasmas, Escape probability methods Nature of physical problem: This code calculates the transport of neutral particles in thermonuclear plasmas in two-dimensional geometric configurations. Method of solution: The code is based on the Transmission and Escape Probability (TEP) methodology [1], which is part of the family of integral transport methods for neutral particles and neutrons. The resulting linear system of equations is solved by standard direct linear system solvers (sparse and non-sparse versions are included). Restrictions on the complexity of the problem: The current version of the code can
NASA Astrophysics Data System (ADS)
Yurovskikh, A. S.; Demakov, S. L.; Kolosova, E. V.
2013-01-01
Special features of formation of the structure of a layered intermetallic material based on titanium aluminide obtained by the method of plasma-spark sintering of foils are studied. The dependence of the structure on the temperature-and-time treatment parameters is determined.
NASA Astrophysics Data System (ADS)
Glushkov, Alexander; Loboda, Andrey; Nikola, Ludmila
2011-10-01
We present the uniform energy approach, formally based on the gauge-invariant relativistic many-body perturbation theory for the calculation of the radiative and autoionization probabilities, electron collision strengths and rate coefficients in a multicharged ions (in a collisionally pumped plasma). An account for the plasma medium influence is carried out within a Debae shielding approach. The aim is to study, in a uniform manner, elementary processes responsible for emission-line formation in a plasma. The energy shift due to the collision is arisen at first in the second PT order in the form of integral on the scattered electron energy. The cross-section is linked with imaginary part of the scattering energy shift. The electron collision excitation cross-sections and rate coefficients for some plasma Ne-, Ar-like multicharged ions are calculated within relativistic energy approach. We present the results of calculation the autoionization resonances energies and widths in heavy He-like multicharged ions and rare-earth atoms of Gd and Tm. To test the results of calculations we compare the obtained data for some Ne-like ions with other authors' calculations and available experimental data for a wide range of plasma conditions.
NASA Astrophysics Data System (ADS)
Priti; Dipti; Gangwar, R. K.; Srivastava, R.
2017-01-01
Electron impact excitation cross-sections and rate coefficients have been calculated using fully relativistic distorted wave theory for several fine-structure transitions from the ground as well as excited states of cesium atom in the wide range of incident electron energy. These processes play dominant role in low pressure hydrogen-cesium plasma, which is relevant to the negative ion based neutral beam injectors for the ITER project. As an application, the calculated detailed cross-sections are used to construct a reliable collisional radiative (CR) model to characterize the hydrogen-cesium plasma. Other processes such as radiative population transfer, electron impact ionization and mutual neutralization of Cs+ ion with negative hydrogen ion along with their reverse processes are also taken into account. The calculated cross-sections and the extracted plasma parameters from the present model are compared with the available experimental and theoretical results.
NASA Astrophysics Data System (ADS)
Bareev, D. D.; Gavrilenko, V. G.; Grach, S. M.; Sergeev, E. N.
2016-02-01
It is shown experimentally that the relaxation time of the stimulated electromagnetic emission (SEE) after the pump wave turn off decreases when frequency of the electromagnetic wave, responsible for the SEE generation (pump wave f0 or diagnostic wave fdw) approaches 4th harmonic of the electron cyclotron frequency fce . Since the SEE relaxation is determined by the damping rate of plasma waves with the same frequency, responsible for the SEE generation, we calculated damping rates of plasma waves with ω ∼ωuh (ω is the plasma wave frequency, ωuh is the upper hybrid frequency) for frequencies close to and distant from the double resonance where ωuh ∼ 4ωce (ωce = 2 πfce). The calculations were performed numerically on the base of linear plasma wave dispersion relation at arbitrary ratio between | Δ | = ω - 4ωce and |k‖ |VTe (VTe is the electron thermal speed and k‖ is the projection of the wave vector onto the magnetic field direction. A comparison of calculation and experimental results has shown that obtained frequency dependence of the SEE decay rate is similar to the damping rate frequency dependence for plasma waves with wave vectors directed at the angles 60-70° to the magnetic field, and gives a strong hint that oblique upper hybrid plasma waves should be responsible for the SEE generation.
Hassanzadeh, Iman; Tabatabaei, Mohammad
2017-03-28
In this paper, controllability and observability matrices for pseudo upper or lower triangular multi-order fractional systems are derived. It is demonstrated that these systems are controllable and observable if and only if their controllability and observability matrices are full rank. In other words, the rank of these matrices should be equal to the inner dimension of their corresponding state space realizations. To reduce the computational complexities, these matrices are converted to simplified matrices with smaller dimensions. Numerical examples are provided to show the usefulness of the mentioned matrices for controllability and observability analysis of this case of multi-order fractional systems. These examples clarify that the duality concept is not necessarily true for these special systems. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.
Kaplan, D
2005-08-31
The purpose of this document is to provide a technically defensible list of distribution coefficients, or Kd values, for use in performance assessment (PA) and special analysis (SA) calculations on the SRS. Only Kd values for radionuclides that have new information related to them or that have recently been recognized as being important are discussed in this report. Some 150 Kd values are provided in this report for various waste-disposal or tank-closure environments: soil, corrosion in grout, oxidizing grout waste, gravel, clay, and reducing concrete environments. Documentation and justification for the selection of each Kd value is provided.
NASA Astrophysics Data System (ADS)
Nosenko, V. Yu.; Pivovarov, A. L.; Chenakin, S. P.; Cherepin, V. T.
1996-04-01
In recent years technological processes and methods of treatment that include the use of low-temperature gas-discharge plasma have become very popular. Ion-plasma technologies are used successfully for cleaning the surface of materials or creating thin-film structures and coatings and for chemicothermal treatment (nitriding, siliconizing, boronizing, carburizing, etc.) of various metals and alloys. The effect of the plasma of a gas glow discharge on a solid body can be manifested in a change in the chemical composition of its surface region. This is caused by the introduction of elements from the gas atmosphere into the specimen and by the redistribution of the matrix components in this region. The nature of such a redistribution of the components under the action of a gas-discharge plasma is not completely clear, which, among other reasons, is associated with the insufficiency of experimental and theoretical data on the problem. The present work concerns the causes and possible mechanism of the appearance of an oxygen-rich layer in the near-surface region of steel 10KhN2 after the action of a glow-discharge plasma in He, N2 + 25% H2, and Ar atmospheres. A correct explanation of this phenomenon can have a decisive role in understanding the special features of the diffusion processes occurring in a solid body under the effect of a gas-discharge plasma.
NASA Astrophysics Data System (ADS)
Kong, Yi; Liu, Baixin
2007-02-01
We investigate, in the present study, the structural properties, magnetic moments and charge distribution of the solid solution in an immiscible Co-Cu system at equilibrium by first-principles calculation using special quasirandom structures (SQS). In order to mimic the pair and multisite correlation functions of the randomly substitutional fcc solid solutions, the original SQS is developed to include five 16-atom SQS unit cells, i.e., 1/16, 2/16, 3/16, 4/16, and 8/16, enabling to mimic at nine specific alloys compositions. Correspondingly, a new error analysis method is proposed for comparing the situations of various alloy compositions within the SQS unit cells having a same number of atoms. The developed SQS are then applied in the first-principles calculation to study the CoxCu1-x solid solutions (x refers to the Co concentration). It turns out that the calculated results of the lattice constants and magnetic moments versus the Co concentration are in good agreement with the experimental data, and especially, the sharp drop in the magnetic moment near the composition x=0.1 is well reproduced. The heats of formation are also calculated and in good agreement with those obtained from Mediema’s thermodynamic theory and available experimental data. At the alloy compositions x=0.25 and 0.75, some hypothetical crystalline structures of the Co-Cu compounds are respectively calculated and their heats of formation are found to be higher than the solid solution counterparts. Finally, the electron distribution among the atoms in the CoxCu1-x solid solutions is studied and the obtained charge densities show that in the CoxCu1-x solid solutions, the charge distributes mostly between the Co-Co atoms, thus forming attractive covalent bonding.
Sakata, S; Enoki, Y; Nakatani, A; Kohzuki, H; Ohga, Y; Shimizu, S
1987-03-01
Methods for the elimination of an inhibitor(s) of erythroid colony formation from plasma were examined in an attempt to measure genuine plasma erythropoietin (Epo) activities with an erythroid colony-forming assay using fetal mouse liver cells. Acid-boiling-chloroform (ABC) treatment was concluded to be the best method because the plasma thus treated stimulated colony formation most and contained the least protein. The dose-response curve for the plasma was parallel to that for the standard Epo preparation. The "erythroid colony-stimulating activity" in the plasma was completely additive to that in the standard Epo, and appeared to be a relatively heat-stable and acid protein with an isoelectric point lower than 5.0. These results suggest that the activity in the plasma is identical to that in the standard Epo. Stability of the plasma Epo activity was dependent on storage temperature and enhanced by adding 1% bovine serum albumin (BSA). Average Epo titers for normal adult, full-term cord, and murine plasmas, all ABC-treated and with 1% BSA added, were 192.4, 184.5, and 150.6 mU/ml, respectively. These values were much higher than those measured by the in vivo standard polycythemic mouse assay.
McCullough, Sheila M; Constable, Peter D
2003-08-01
To determine values for the total concentration of nonvolatile weak acids (Atot) and effective dissociation constant of nonvolatile weak acids (Ka) in plasma of cats. Convenience plasma samples of 5 male and 5 female healthy adult cats. Cats were sedated, and 20 mL of blood was obtained from the jugular vein. Plasma was tonometered at 37 degrees C to systematically vary PCO2 from 8 to 156 mm Hg, thereby altering plasma pH from 6.90 to 7.97. Plasma pH, PCO2, and concentrations of quantitatively important strong cations (Na+, K+, and Ca2+), strong anions (Cl-, lactate), and buffer ions (total protein, albumin, and phosphate) were determined. Strong ion difference was estimated from the measured strong ion concentrations and nonlinear regression used to calculate Atot and Ka from the measured pH and PCO2 and estimated strong ion difference. Mean (+/- SD) values were as follows: Atot = 24.3 +/- 4.6 mmol/L (equivalent to 0.35 mmol/g of protein or 0.76 mmol/g of albumin); Ka = 0.67 +/- 0.40 x 10(-7); and the negative logarithm (base 10) of Ka (pKa) = 7.17. At 37 degrees C, pH of 7.35, and a partial pressure of CO2 (PCO2) of 30 mm Hg, the calculated venous strong ion difference was 30 mEq/L. These results indicate that at a plasma pH of 7.35, a 1 mEq/L decrease in strong ion difference will decrease pH by 0.020, a 1 mm Hg decrease in PCO2 will increase plasma pH by 0.011, and a 1 g/dL decrease in albumin concentration will increase plasma pH by 0.093.
Florido, R.; Rodriguez, R.; Gil, J. M.; Rubiano, J. G.; Martel, P.; Minguez, E.; Sauvan, R.; Mancini, R.
2008-10-22
This work describes ABAKO/RAPCAL, a flexible computational package for the study of population kinetics and radiative properties of non-equilibrium plasmas in a wide range of physical conditions. The code was developed looking for an optimal compromise between accuracy and computational cost. ABAKO/RAPCAL assembles a set of simple analytical models which yield substantial savings of computer resources, but yet still providing good comparisons with more elaborated codes and experimental data. Here we present some results to show the ABAKO/RAPCAL capabilities to calculate the charge distribution and radiative properties of both low- and high-Z plasmas. Finally, an application for K-shell spectroscopic determination of the electron temperature and density of laser-produced plasmas is also shown.
Constable, Peter D
2002-04-01
To calculate values for the total concentration of nonvolatile weak acids (Atot) and the effective dissociation constant for nonvolatile weak acids (Ka) of bovine plasma and to determine the best method for quantifying the unmeasured strong anion concentration in bovine plasma. Data sets from published and experimental studies. The simplified strong ion model was applied to published and experimentally determined values for pH, PCO2, and strong ion difference (SID+). Nonlinear regression was used to solve simultaneously for Atot and Ka. Four methods for quantifying the unmeasured strong anion concentration in plasma (anion gap, the Fencl base excess method [BEua], the Figge unmeasured anion method [XA], and the strong ion gap [SIG]) were compared in 35 cattle with abomasal volvulus. For bovine plasma at 37 C, Atot was 25 m M/L, equivalent to 76 times the albumin concentration or 3.6 times the total protein concentration; Ka was 0.87 x 10(-7), equivalent to pKa of 706. The Atot and Ka values were validated, using data sets from in vivo and in vitro studies. Plasma unmeasured strong anion concentration was most accurately predicted in critically ill cattle by calculating SIG from serum albumin (R2, 0.66) or total protein concentration (R2, 0.60), compared with BEua (R2, 0.56), [XA] (R2, 0.50), and the anion gap (R2, 0.41). Calculated values for Atot, Ka, and the SIG equation should facilitate application of the strong ion approach to acid-base disturbances in cattle.
Steinbach, Sarah M L; Sturgess, Christopher P; Dunning, Mark D; Neiger, Reto
2015-06-01
Assessment of renal function by means of plasma clearance of a suitable marker has become standard procedure for estimation of glomerular filtration rate (GFR). Sinistrin, a polyfructan solely cleared by the kidney, is often used for this purpose. Pharmacokinetic modeling using adequate software is necessary to calculate disappearance rate and half-life of sinistrin. The purpose of this study was to describe the use of a Microsoft excel based add-in program to calculate plasma sinistrin clearance, as well as additional pharmacokinetic parameters such as transfer rates (k), half-life (t1/2) and volume of distribution (Vss) for sinistrin in dogs with varying degrees of renal function. Copyright © 2015 Elsevier Ltd. All rights reserved.
Shinohara, Kouji; Kim, Junghee; Kim, Jun Young; Rhee, Tongnyeol
2016-11-01
The orbits of lost ions can be calculated from the information obtained by a fast ion loss detector (FILD). The orbits suggest a source of the lost fast ions in a phase space. However, it is not obvious whether an observable set of orbits, or phase space, of a FILD appropriately covers the region of interest to be investigated since the observable phase space can be affected by plasma facing components (PFCs) and a magnetic configuration. A tool has been developed to evaluate the observable phase space of FILD diagnostic by calculating particle orbits by taking the PFCs and 3D magnetic field into account.
NASA Astrophysics Data System (ADS)
Gulov, A. V.; Derzhiev, V. I.; Zhidkov, A. G.; Pritula, A. G.; Chekmezov, A. N.; Yakovlenko, Sergei I.
1990-08-01
Calculations are reported of the gain due to the 3-2 transition in the C VI ion in an expanding plasma cylinder or a cylindrical layer. Under the conditions in the experiments at the Rutherford Appleton Laboratory (Chilton, England) amplification was observed as a result of evaporation of a fairly thin (~ 0.1 μm) cylindrical layer. A peak of the gain was reached in a relatively short time (~ 0.1 ns).
NASA Astrophysics Data System (ADS)
Hey, J. D.
2015-09-01
On the basis of the original definition and analysis of the vector operator by Pauli (1926 Z. Phys. 36 336-63), and further developments by Flamand (1966 J. Math. Phys. 7 1924-31), and by Becker and Bleuler (1976 Z. Naturforsch. 31a 517-23), we consider the action of the operator on both spherical polar and parabolic basis state wave functions, both with and without direct use of Pauli’s identity (Valent 2003 Am. J. Phys. 71 171-75). Comparison of the results, with the aid of two earlier papers (Hey 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2641-64, Hey 2007 J. Phys. B: At. Mol. Opt. Phys. 40 4077-96), yields a convenient ladder technique in the form of a recurrence relation for calculating the transformation coefficients between the two sets of basis states, without explicit use of generalized hypergeometric functions. This result is therefore very useful for application to Stark effect and impact broadening calculations applied to high-n radio recombination lines from tenuous space plasmas. We also demonstrate the versatility of the Runge-Lenz-Pauli vector operator as a means of obtaining recurrence relations between expectation values of successive powers of quantum mechanical operators, by using it to provide, as an example, a derivation of the Kramers-Pasternack relation. It is suggested that this operator, whose potential use in Stark- and Zeeman-effect calculations for magnetically confined fusion edge plasmas (Rosato, Marandet and Stamm 2014 J. Phys. B: At. Mol. Opt. Phys. 47 105702) and tenuous space plasmas ( H II regions) has not been fully explored and exploited, may yet be found to yield a number of valuable results for applications to plasma diagnostic techniques based upon rate calculations of atomic processes.
NASA Astrophysics Data System (ADS)
Silin, I.; Toffoletto, F.; Wolf, R.; Sazykin, S. Y.
2013-12-01
We present a finite-volume MHD code for simulations of magnetospheric dynamics of the plasma sheet and the inner magnetosphere. The code uses staggered non-uniform Cartesian grids to preserve the divergence-free magnetic fields, along with various numerical approximations and flux limiters for the plasma variables. The code can be initialized with empirical magnetic field models, such as the Tsyganenko models along with pressure information from either the Tsyganenko-Mukai models, or observational data, such as DMSP pressure maps. Artificial "friction term" can be added to the momentum equation, which turns the MHD code into "magnetofriction" code which can be used to construct approximate equilibrium solutions. We demonstrate some applications for our code, in both the "magnetofriction" and MHD mode, including relaxation of the empirical models to equilibrium and the evolution of a plasma bubble in the near magnetotail. The latter MHD simulation results exhibit oscillations about their equilibrium position in agreement with recent observations.
Whitley, Heather D.; Scullard, Christian R.; Benedict, Lorin X.; ...
2014-12-04
Here, we present a discussion of kinetic theory treatments of linear electrical and thermal transport in hydrogen plasmas, for a regime of interest to inertial confinement fusion applications. In order to assess the accuracy of one of the more involved of these approaches, classical Lenard-Balescu theory, we perform classical molecular dynamics simulations of hydrogen plasmas using 2-body quantum statistical potentials and compute both electrical and thermal conductivity from out particle trajectories using the Kubo approach. Our classical Lenard-Balescu results employing the identical statistical potentials agree well with the simulations.
NASA Technical Reports Server (NTRS)
Bathke, C. G.
1976-01-01
Electron energy distribution functions were calculated in a U235 plasma at 1 atmosphere for various plasma temperatures and neutron fluxes. The distributions are assumed to be a summation of a high energy tail and a Maxwellian distribution. The sources of energetic electrons considered are the fission-fragment induced ionization of uranium and the electron induced ionization of uranium. The calculation of the high energy tail is reduced to an electron slowing down calculation, from the most energetic source to the energy where the electron is assumed to be incorporated into the Maxwellian distribution. The pertinent collisional processes are electron-electron scattering and electron induced ionization and excitation of uranium. Two distinct methods were employed in the calculation of the distributions. One method is based upon the assumption of continuous slowing and yields a distribution inversely proportional to the stopping power. An iteration scheme is utilized to include the secondary electron avalanche. In the other method, a governing equation is derived without assuming continuous electron slowing. This equation is solved by a Monte Carlo technique.
NASA Astrophysics Data System (ADS)
Noel, Jean
The feasibility of a two dimensional computation code for electric arc plasma is addressed. The nonstationary physics of a plasma arc can intervene at high gradients on all the variables, a high convection, as well as the considerable pressure variations (in space and time). Here the spatial finesse needed for the treatment of high gradient zones, is obtained by the use of a finite element method, improved by a mesh auto-adaptivity. The chosen time integration method is of the Runge-Kutta type with time step adjustment. This is presented, with the numerical methodology principles (multimesh, regularization, time step control). Results obtained in the study of classical partial differential equation systems, simplified versions of the Navier-Stokes equations (Burger equation, Dwyer-Sanders flame model), are presented. The numerical treatment of a confined arc plasma required the preliminary definition of a representative system of equations. This system is presented, with the thermal and dynamic modelings carried out. Different aspects of the models introduced are illustrated, and results obtained for an unstationary one dimensional arc plasma in industrial conditions are presented. Comparisons between these results and available experimental data are encouraging, but suggest that a better dynamic modeling is indispensable.
Berezhkovskiy, Leonid M
2016-08-01
An uncommon innovative consideration of the well-stirred linear physiologically based pharmacokinetic model and the drug plasma concentration-time profile, which is measured in routine intravenous bolus pharmacokinetic study, was applied for the calculation of the drug time course in human tissues. This cannot be obtained in the in vivo pharmacokinetic study. The physiological parameters of the organ such as organ tissue volume, organ blood flow rate, and its vascular volume were used in the calculation. The considered method was applied to calculate the time course of midazolam, alprazolam, quinidine, and diclofenac in human organs or tissues. The suggested method might be applied for the prediction of drug concentration-time profile in tissues and consequently the drug concentration level in the targeted tissue, as well as the possible undesirable toxic levels in other tissues. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.
Calculation of ρ R-parameter and Energy Gain for Aneutronic Fusion in Degenerate P-11 B Plasma
NASA Astrophysics Data System (ADS)
Hosseini Motlagh, S. N.; Mohamadi, Sh. S.; Shamsi, R.
2008-09-01
Aneutronic fusion reactions are more safe and clean than the other reactions. One of the important candidate for these reactions is P-11 B. This reaction in characteristic conditions creates degenerate plasma. In a Fermi-degenerate plasma, the electronic stopping of a slow ion is smaller than given by the classical formula, because some transitions between the electron states are forbidden. The bremsstrahlung losses are then smaller, so that the nuclear burning of an aneutronic fuel is more efficient. Practical obstacles in this regime that must be overcome before net energy can be realized include the compression of the fuel to an ultra dense state and the creation of a hot spot. In this paper, ρ R parameter (Lawson's criterion) and energy gain for P-11 B are given.
Swadling, G F; Ross, J S; Datte, P; Moody, J; Divol, L; Jones, O; Landen, O
2016-11-01
An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm(-2). This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 10(19) cm(-2) Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.
NASA Astrophysics Data System (ADS)
Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O.
2016-11-01
An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ˜8 J cm-2. This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 1019 cm-2 Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.
Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O.
2016-11-15
An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause “blanking” (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ∼8 J cm{sup −2}. This is significantly above the expected threshold for the onset of “blanking” effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate “blanking.” Estimates suggest that an areal density of 10{sup 19} cm{sup −2} Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.
Hannachi, R.; Cressault, Y.; Teulet, Ph.; Gleizes, A.; Ben Lakhdar, Z.; Taieeb, G.
2007-09-19
The resonance escape factors for the lines emitted by a neutral magnesium atom MgI at 285.2127 nm (3 {sup 1}S-3 {sup 1}P) and of ionic magnesium MgII at 279.5528 nm (3 {sup 2}S-3 {sup 2}P) are calculated assuming a Voigt profile and in the case of MgCl{sub 2}-water plasma. The dependence of the escape factor on the optical thickness {tau}{sub 0} from the line center which itself depends on the two main spectral line shape broadening mechanisms (pressure and Doppler effects) are considered. The variation of the resonance escape factors with the temperature and the MgCl{sub 2} molar proportion are also investigated. This calculation is useful for the application of laser induced breakdown spectroscopy in the quantitative analysis of elemental composition.
Anstey, Chris M
2005-06-01
Currently, three strong ion models exist for the determination of plasma pH. Mathematically, they vary in their treatment of weak acids, and this study was designed to determine whether any significant differences exist in the simulated performance of these models. The models were subjected to a "metabolic" stress either in the form of variable strong ion difference and fixed weak acid effect, or vice versa, and compared over the range 25 < or = Pco(2) < or = 135 Torr. The predictive equations for each model were iteratively solved for pH at each Pco(2) step, and the results were plotted as a series of log(Pco(2))-pH titration curves. The results were analyzed for linearity by using ordinary least squares regression and for collinearity by using correlation. In every case, the results revealed a linear relationship between log(Pco(2)) and pH over the range 6.8 < or = pH < or = 7.8, and no significant difference between the curve predictions under metabolic stress. The curves were statistically collinear. Ultimately, their clinical utility will be determined both by acceptance of the strong ion framework for describing acid-base physiology and by the ease of measurement of the independent model parameters.
Martinuzzo, M; Barrera, L; Rodriguez, M; D'Adamo, M A; López, M S; Otaso, J C
2015-12-01
Prothrombin time (PT) and activated partial thromboplastin time (APTT) sensitivity for detecting isolated factor deficiencies varies with different reagents and coagulometers. The Clinical and Laboratory Standards Institute (CLSI) H47A2 guideline proposed a method to calculate these sensitivities, but some inconsistency has been reported. This study aimed to calculate factor sensitivities using CLSI guideline and to compare them with those obtained from single factor-deficient patients' data. Different mixtures of normal pooled and deficient plasmas were prepared (<1IU/dL to 100 IU/dL) according to the CLSI H47A2 guideline. PT with rabbit brain (RB) and human recombinant (HR) thromboplastins, APTT and factors' activities were measured in an ACL TOP coagulometer. Sensitivities (maximum factor concentration that produces PT or APTT values out of the reference range) were calculated from mixtures and from patients with single-factor deficiencies: 17 factor FV, 36 FVII, 19 FX, 39 FVIII, 15 FIX 15 FXI and 24 FXII. PT sensitivity with RB was as follows: FV 38 and 59, FVII 35 and 58, FX 56 and 64 IU/dL; PT sensitivity with HR was as follows: FV 39 and 45, FVII 51 and 50, FX 33 and 61 IU/dL; and APTT sensitivity was as follows: FV 39 and 45, FX 32 and 38, FVIII 47 and 60, FIX 35 and 44, FXI 33 and 43, FXII 37 and 46 IU/dL, respectively. Reagent-coagulometer combination has adequate sensitivities to factor deficiencies according to guideline recommendations (>30 IU/dL). These should not be considered as actual sensitivities because those obtained by analysing patients' plasmas with single-factor deficiencies were higher for most factors and could induce misinterpretation of the basic coagulation test results. © 2015 John Wiley & Sons Ltd.
NASA Astrophysics Data System (ADS)
Roche, T.; Thompson, M. C.; Mendoza, R.; Allfrey, I.; Garate, E.; Romero, J.; Douglass, J.
2016-11-01
External flux conserving coils were installed onto the exterior of the C-2U [M. W. Binderbauer et al., Phys. Plasmas 22, 056110 (2015)] confinement vessel to increase the flux confinement time of the system. The 0.5 in. stainless steel vessel wall has a skin time of ˜5 ms. The addition of the external copper coils effectively increases this time to ˜7 ms. This led to better-confined/longer-lived field-reversed configuration (FRC) plasmas. The fringing fields generated by the external coils have the side effect of rendering external field measurements invalid. Such measurements were key to the previous method of excluded flux calculation [M. C. Thompson et al., Rev. Sci. Instrum. 83, 10D709 (2012)]. A new array of B-dot probes and Rogowski coils were installed to better determine the amount of flux leaked out of the system and ultimately provide a more robust measurement of plasma parameters related to pressure balance including the excluded flux radius. The B-dot probes are surface mountable chip inductors with inductance of 33 μH capable of measuring the DC magnetic field and transient field, due to resistive current decay in the wall/coils, when coupled with active integrators. The Rogowski coils measure the total change in current in each external coil (150 A/2 ms). Currents were also actively driven in the external coils. This renders the assumption of total flux conservation invalid which further complicates the analysis process. The ultimate solution to these issues and the record breaking resultant FRC lifetimes will be presented.
Roche, T. Thompson, M. C.; Mendoza, R.; Allfrey, I.; Garate, E.; Romero, J.; Douglass, J.
2016-11-15
External flux conserving coils were installed onto the exterior of the C-2U [M. W. Binderbauer et al., Phys. Plasmas 22, 056110 (2015)] confinement vessel to increase the flux confinement time of the system. The 0.5 in. stainless steel vessel wall has a skin time of ∼5 ms. The addition of the external copper coils effectively increases this time to ∼7 ms. This led to better-confined/longer-lived field-reversed configuration (FRC) plasmas. The fringing fields generated by the external coils have the side effect of rendering external field measurements invalid. Such measurements were key to the previous method of excluded flux calculation [M. C. Thompson et al., Rev. Sci. Instrum. 83, 10D709 (2012)]. A new array of B-dot probes and Rogowski coils were installed to better determine the amount of flux leaked out of the system and ultimately provide a more robust measurement of plasma parameters related to pressure balance including the excluded flux radius. The B-dot probes are surface mountable chip inductors with inductance of 33 μH capable of measuring the DC magnetic field and transient field, due to resistive current decay in the wall/coils, when coupled with active integrators. The Rogowski coils measure the total change in current in each external coil (150 A/2 ms). Currents were also actively driven in the external coils. This renders the assumption of total flux conservation invalid which further complicates the analysis process. The ultimate solution to these issues and the record breaking resultant FRC lifetimes will be presented.
NASA Astrophysics Data System (ADS)
Dongming, Zhang; Lianmeng, Zhang; Xiaofeng, Gu; Fei, Chen
2008-02-01
The high intensity of thermal stress was generated during fabrication of 6063 aluminum/60SiC-35Al-5Si double-layer material. In order to decrease the thermal stress, graded materials of Al/60SiC-35Al-5Si was fabricated by spark plasma sintering. The CTE in the graded layer was controlled by SiC fraction and particle sizes. The calculation results indicate that the net stress of more than 800 MPa was generated in the double-layer materials, but it decreased to 170 MPa or less in the graded materials. So the stability can be guaranteed in the graded composites. The graded layers also have the potential for high thermal conductivity, more than 180W/Mk for every layer, which satisfies the application.
Programmable calculator stress analysis
Van Gulick, L.A.
1983-01-01
Advanced programmable alphanumeric calculators are well suited for closed-form calculation of pressure-vessel stresses. They offer adequate computing power, portability, special programming features, and simple interactive execution procedures. Representative programs that demonstrate calculator capabilities are presented. Problems treated are stress and strength calculations in thick-walled pressure vessels and the computation of stresses near head/pressure-vessel junctures.
NASA Astrophysics Data System (ADS)
Denis-Petit, David; Gosselin, Gilbert; Hannachi, Fazia; Tarisien, Medhi; Bonnet, Thomas; Comet, Maxime; Gobet, Franck; Versteegen, Maud; Morel, Pascal; Méot, Vincent; Matea, Iolanda
2017-08-01
One promising candidate for the first detection of nuclear excitation in plasma is the 463-keV, 20.26-min-lifetime isomeric state in 84Rb, which can be excited via a 3.5-keV transition to a higher lying state. According to our preliminary calculations, under specific plasma conditions, nuclear excitation by electron transition (NEET) may be its strongest excitation process. Evaluating a reliable NEET rate requires, in particular, a thorough examination of all atomic transitions contributing to the rate under plasma conditions. We report the results of a detailed evaluation of the NEET rate based on multiconfiguration Dirac Fock (MCDF) atomic calculations, in a rubidium plasma at local thermodynamic equilibrium with a temperature of 400 eV and a density of 10-2g /cm3 and based on a more precise energy measurement of the nuclear transition involved in the excitation.
Ivanov, A. A. Martynov, A. A. Medvedev, S. Yu. Poshekhonov, Yu. Yu.
2015-03-15
In the MHD tokamak plasma theory, the plasma pressure is usually assumed to be isotropic. However, plasma heating by neutral beam injection and RF heating can lead to a strong anisotropy of plasma parameters and rotation of the plasma. The development of MHD equilibrium theory taking into account the plasma inertia and anisotropic pressure began a long time ago, but until now it has not been consistently applied in computational codes for engineering calculations of the plasma equilibrium and evolution in tokamak. This paper contains a detailed derivation of the axisymmetric plasma equilibrium equation in the most general form (with arbitrary rotation and anisotropic pressure) and description of the specialized version of the SPIDER code. The original method of calculation of the equilibrium with an anisotropic pressure and a prescribed rotational transform profile is proposed. Examples of calculations and discussion of the results are also presented.
NASA Technical Reports Server (NTRS)
Jones, Alun R.
1940-01-01
This report has been prepare in response to a request for information from an aircraft company. A typical example was selected for the presentation of an approximate method of calculation of the relative humidity required to prevent frosting on the inside of a plastic window in a pressure type cabin on a high speed airplane. The results of the study are reviewed.
Slater, C.O.
1992-01-01
The DRC2 code, which couples MASH or MASHX adjoint leakages with DORT 2-D discrete ordinates forward directional fluences, is described. The forward fluences are allowed to vary both axially and radially over the coupling surface, as opposed to the strictly axial variation allowed by the predecessor DRC code. Input instructions are presented along with descriptions and results from several sample problems. Results from the sample problems are used to compare DRC2 with DRC, DRC2 with DORT, and DRC2 with itself for the case of x-y dependence versus no x-y dependence of the forward fluence. The test problems demonstrate that for small systems DRC and DRC2 give essentially the same results. Some significant differences are noted for larger systems. Additionally, DRC2 results with no x-y dependence of the forward directional fluences are practically the same as those calculated by DRC.
NASA Astrophysics Data System (ADS)
Pollmann, D.; Leis, F.; Tölg, G.; Tschöpel, P.; Broekaert, J. A. C.
1994-12-01
The use of inductively coupled plasma mass spectrometry (ICP-MS) for the determination of trace elements in Al 2O 3 powders is reported. Special interest is given to a preconcentration of the trace elements by on-line coupling of chromatography to ICP-MS. This is based on the complexation of Co, Cu, Cr, Fe, Ga, Mn, Ni, V and Zn with hexamethylene-dithiocarbamate (HMDC), their preconcentration on a C18 RP column by reversed phase liquid chromatography and their elution with CH 3OH-H 2O mixtures. A direct coupling of the HPLC system to the ICP-MS has been realized by high pressure pneumatic nebulization using desolvation. With the Chromatographie method developed, removal of the AI by at least 99% was achieved. For the trace elements V, Fe, Ni, Co, Cu and Ga, high and reproducible recoveries (ranging from 96-99%) were reached. The method developed has been shown to considerably enhance the power of detection as compared with direct procedures, namely down to 0.02-0.16 ( μg/g for V and Fe, respectively. The possibilities of the method are shown by the determinations of V, Mn, Fe, Ni, Co, Cu, Zn and Ga at the μg/g level in A1 2O 3 powders. The accuracy of the method at the 0.06 to 9.0 μg/g level for Co and Fe, respectively, is demonstrated by a comparison with results of independent methods from the literature.
NASA Astrophysics Data System (ADS)
Joglekar, Archis; Thomas, Alec
2013-10-01
Here, we present 2D numerical modeling of near critical density plasma using a fully implicit Vlasov-Fokker-Planck code, IMPACTA, which includes self-consistent magnetic fields as well as anisotropic electron pressure terms in the expansion of the distribution function, as well as an implementation of the Boris CYLRAD algorithm through a ray tracing add-on package. This allows to model inverse brehmsstrahlung heating as a laser travels through a plasma by solving the ray tracing equations. Generated magnetic fields (eg. the Biermann battery effect) as well as field advection through heat fluxes from the laser heating is shown. Additionally, perturbations in the plasma density profile arise as a result of the high pressures and flows in the plasma. These perturbations in the plasma density affect the path of the laser traveling through the plasma and modify the heating profile accordingly. The interplay between these effects is discussed in this study.
Plasma gasification of carbonaceous wastes: thermodynamic analysis and experiment
NASA Astrophysics Data System (ADS)
Messerle, V. E.; Mosse, A. L.; Ustimenko, A. B.
2016-07-01
Thermodynamic calculations of the plasma gasification process of carbonaceous wastes in air and steam ambient were carried out. A maximum yield of synthesis gas in such processes is predicted to be achieved at a temperature of 1600 K. On a specially developed plasma facility, plasma gasification experiments were performed for carbonaceous wastes. From the organic mass of carbonaceous waste and from its mineral mass, respectively, a high-calorific syngas and a neutral slag consisting predominantly of ferric carbide, calcium monosilicate, silica and iron, were obtained. A comparison between the experiment and the calculations has shown a good consistency between the data.
Wave propagation in a moving cold magnetized plasma
NASA Astrophysics Data System (ADS)
Hebenstreit, H.
1980-03-01
Polarization relations and dispersion equations are derived for media that are electrically anisotropic in the comoving frame. Three-dimensional calculations for media at rest recover the known dispersion equations, i.e., Astrom's dispersion equation for magnetized cold plasmas and Fresnel's wave normal equation for uniaxial crystals. An analogous four-dimensional calculation yields the generalization to moving media. The dispersion equations so obtained for moving gyrotropic media are then discussed qualitatively for various special media and special directions of wave propagation. Finally, the polarization relations are specialized to media gyrotropic in the comoving frame.
NASA Astrophysics Data System (ADS)
Brualla, L.; Mayorga, P. A.; Flühs, A.; Lallena, A. M.; Sempau, J.; Sauerwein, W.
2012-11-01
Retinoblastoma is the most common eye tumour in childhood. According to the available long-term data, the best outcome regarding tumour control and visual function has been reached by external beam radiotherapy. The benefits of the treatment are, however, jeopardized by a high incidence of radiation-induced secondary malignancies and the fact that irradiated bones grow asymmetrically. In order to better exploit the advantages of external beam radiotherapy, it is necessary to improve current techniques by reducing the irradiated volume and minimizing the dose to the facial bones. To this end, dose measurements and simulated data in a water phantom are essential. A Varian Clinac 2100 C/D operating at 6 MV is used in conjunction with a dedicated collimator for the retinoblastoma treatment. This collimator conforms a ‘D’-shaped off-axis field whose irradiated area can be either 5.2 or 3.1 cm2. Depth dose distributions and lateral profiles were experimentally measured. Experimental results were compared with Monte Carlo simulations’ run with the penelope code and with calculations performed with the analytical anisotropic algorithm implemented in the Eclipse treatment planning system using the gamma test. penelope simulations agree reasonably well with the experimental data with discrepancies in the dose profiles less than 3 mm of distance to agreement and 3% of dose. Discrepancies between the results found with the analytical anisotropic algorithm and the experimental data reach 3 mm and 6%. Although the discrepancies between the results obtained with the analytical anisotropic algorithm and the experimental data are notable, it is possible to consider this algorithm for routine treatment planning of retinoblastoma patients, provided the limitations of the algorithm are known and taken into account by the medical physicist and the clinician. Monte Carlo simulation is essential for knowing these limitations. Monte Carlo simulation is required for optimizing the
NASA Astrophysics Data System (ADS)
Fairushin, I. I.; Dautov, I. G.; Kashapov, N. F.; Shamsutdinov, A. R.
2017-01-01
Self-consistent spatial distributions of the electron density in the entire volume of condensed-matter particles and the surrounding plasma, as well as distributions of the concentration of ions of easily ionized impurity atoms, are obtained using the jellium model to describe particles. It is established that electron emission from condensed particles in a thermal dusty plasma containing an impurity of an easily ionized element may weaken with an increase in temperature. The electron emission from particles is shown to increase with a decrease in their radius at a constant temperature. A plasma region with violated ionization equilibrium is found to form near the surface of condensed particles.
ERIC Educational Resources Information Center
Clarke, Jacqueline
2001-01-01
Presents unique ways to create special rituals that recognize individual students' achievements and milestones. Ideas include throwing a send-off party for a student who is moving; holding monthly birthday luncheons; choosing an ambassador to accompany new students around school; and making a lost tooth container that students can use to safely…
ERIC Educational Resources Information Center
Clarke, Jacqueline
2001-01-01
Presents unique ways to create special rituals that recognize individual students' achievements and milestones. Ideas include throwing a send-off party for a student who is moving; holding monthly birthday luncheons; choosing an ambassador to accompany new students around school; and making a lost tooth container that students can use to safely…
Zaghloul, Mofreh R.
2010-12-15
The problem of the calculation of equilibrium thermodynamic properties and the establishment of statistical-thermodynamically consistent finite bound-state partition functions in nonideal multicomponent plasma systems is revised within the chemical picture. The present exploration accompanied by the introduction of a generalized consistent formulation, in terms of the solution of the inverse problem, clears ambiguities and gives a better understanding of the problem on top of pointing out weaknesses and inaccuracies/inconsistencies buried in widely used models in literature.
Johnstone, I B; Martin, C A
2000-01-01
The commercial snake venom extract, Protac, is a specific activator of the anticoagulant zymogen, protein C (PC) in human plasma. This specific action has led to its use in developing coagulation-based and amidolytic-based assays for the diagnosis of quantitative and/or qualitative PC deficiency states in human beings. The purpose of the present study was to compare the effects of Protac on the activated partial thromboplastin times (APTT) of human, bovine, equine, and canine plasmas in order to determine the potential value of this venom extract as an activator in functional PC assays in these domestic animal species. As expected, Protac significantly prolonged the APTT of normal human plasma, but had no effect on plasma known to be devoid of PC. Clotting times were prolonged by 34%-214% with concentrations of venom activator ranging from 0.1-1.0 U/mL. Under identical conditions, Protac prolonged the APTT of equine plasma by 11%-98% over control times. Even more dramatic was the inhibitory effect of Protac on the clotting of bovine plasma, extending the APTT more than 3-fold at a venom concentration of 0.1 U/mL. At higher venom concentrations, most bovine plasmas remained unclotted after 300 s (control time 34.1 s). Under similar conditions, the canine APTT was unaffected by Protac, even when the venom concentration was increased to 3 U/mL. In order to determine the reason for the lack in response of canine plasma, the concentration of the APTT reagent was altered (decreased), exposure time of the plasma to the Protac was increased from 2 min to 9 min, and the plasma was diluted to assess for the potential existence of plasma PC inhibitors. Protac caused an unexpected shortening of the APTT when the contact activator reagent was diluted. Increasing the exposure time had no effect. Although a slight prolongation of the canine APTT was detected when the plasma was diluted, the presence of strong plasma PC inhibition was considered an unlikely cause of the lack of
Skiff, Fred; Davidson, Ronald C.
2013-05-15
Each year, the annual meeting of the APS Division of Plasma Physics (DPP) brings together a broad representation of the many active subfields of plasma physics and enjoys an audience that is equally diverse. The meeting was well attended and largely went as planned despite the interventions of hurricane Sandy which caused the city of Providence to shut-down during the first day of the conference. The meeting began on Monday morning with a review of the physics of cosmic rays, 2012 being the 100th year since their discovery, which illustrated the central importance of plasma physics to astrophysical problems. Subsequent reviews covered the importance of tokamak plasma boundaries, progress towards ignition on the National Ignition Facility (NIF), and magnetized plasma turbulence. The Maxwell prize address, by Professor Liu Chen, covered the field of nonlinear Alfvén wave physics. Tutorial lectures were presented on the verification of gyrokinetics, new capabilities in laboratory astrophysics, magnetic flux compression, and tokamak plasma start-up.
NASA Astrophysics Data System (ADS)
Skiff, Fred; Davidson, Ronald C.
2013-05-01
Each year, the annual meeting of the APS Division of Plasma Physics (DPP) brings together a broad representation of the many active subfields of plasma physics and enjoys an audience that is equally diverse. The meeting was well attended and largely went as planned despite the interventions of hurricane Sandy which caused the city of Providence to shut-down during the first day of the conference. The meeting began on Monday morning with a review of the physics of cosmic rays, 2012 being the 100th year since their discovery, which illustrated the central importance of plasma physics to astrophysical problems. Subsequent reviews covered the importance of tokamak plasma boundaries, progress towards ignition on the National Ignition Facility (NIF), and magnetized plasma turbulence. The Maxwell prize address, by Professor Liu Chen, covered the field of nonlinear Alfvén wave physics. Tutorial lectures were presented on the verification of gyrokinetics, new capabilities in laboratory astrophysics, magnetic flux compression, and tokamak plasma start-up.
NASA Astrophysics Data System (ADS)
Shikama, T.; Fujii, K.; Mizushiri, K.; Hasuo, M.; Kado, S.; Zushi, H.
2009-12-01
A scheme for computation of emission spectra of light diatomic molecules under external magnetic and electric fields is presented. As model species in fusion edge plasmas, the scheme is applied to polarization-resolved emission spectra of H2, CH, C2, BH and BeH molecules. The possibility of performing spatially resolved measurements of these spectra is examined.
Liu, Chang; Dodin, Ilya Y.
2015-08-15
The nonlinear frequency shift is derived in a transparent asymptotic form for intense Langmuir waves in general collisionless plasma. The formula describes both fluid and kinetic effects simultaneously. The fluid nonlinearity is expressed, for the first time, through the plasma dielectric function, and the kinetic nonlinearity accounts for both smooth distributions and trapped-particle beams. Various known limiting scalings are reproduced as special cases. The calculation avoids differential equations and can be extended straightforwardly to other nonlinear plasma waves.
Current collection from an unmagnetized plasma: A tutorial
NASA Technical Reports Server (NTRS)
Whipple, Elden C.
1990-01-01
The current collected by a body in an unmagnetized plasma depends in general on: (1) the properties of the plasma; (2) the properties of the body; and (3) the properties of any neutral species that are present. The important plasma properties are the velocity distributions of the plasma particles at a location remote from the body (at infinity), and the Debye length which determines the importance of plasma space charge effects. The important body properties are its surface characteristics, namely the conductivity and secondary yield coefficients. The neutral species affect the current through collisions which impede the flow of current and possibly through ionization of the neutrals which can enhance the current. The technique for calculating the current collected by a body in a plasma is reviewed with special attention given to the distinction between orbit limited and space charge limited regimes, the asymptotic variation of the potential with distance from a body, and the concept of a sheath.
Meyerhofer, D. D.; Mauel, M. E.
2016-05-18
The 57th annual meeting of the APS Division of Plasma Physics (DPP) was held November 16–20, 2015 in Savannah, Georgia. The meeting brings together researchers (undergraduate students through retirees) from all areas of plasma physics. 1887 abstracts were included in the program, approximately 200 more than the previous year. The presentations included five invited review talks, 97 invited talks, three invited postdeadline talks, and four tutorials. Furthermore, there were approximately 1780 contributed presentations, with about 40% oral and 60% poster. Three mini-conferences were held concurrently.
Stability of Alfven oscillations in a plane plasma slab
Patudin, V.M.; Sagalakov, A.M.
1983-05-01
The stability of the natural Alfven oscillations of a plane slab of a collisional, slightly nonequilibrium plasma in a uniform magnetic field is studied. An effective numerical method, a special version of the differential sweepout method, is proposed. A calculation procedure has been developed. The small-oscillation spectrum is analyzed for parabolic plasma density profiles, and neutral curves are plotted. The growth rates and critical parameters are determined. At a high plasma conductivity, both strongly and weakly localized perturbations near the axis can go unstable. For a density profile with an inflection point, weakly damped oscillations are observed near the inflection point. These oscillations can also be excited by an ion beam.
Himeno, Mariko; Ishibashi, Takaharu; Nakano, Shigeru; Furuya, Keisuke; Kigoshi, Toshikazu; Uchida, Kenzo; Nishio, Matomo
2003-02-01
To establish a concrete procedure to achieve a steady state plasma NOx concentration with Japanese daily food, NOx contents of about 200 types of food and beverages consumed daily were measured and NOx concentration in plasma was monitored till steady state after various degree of intake of NOx restricted food. The NOx content was found to be high in dark green leaved vegetables and low in grains, processed food, fresh and processed seafood. Tap water and mineral water were found to contain various amounts of NOx that were drastically reduced by treatment with a reverse osmosis column and remained in trace amounts after ion exchange column treatment. NOx content was low in drinks such as cola, but was extremely high in vegetable juice containing dark green leaved vegetables. The intake of high NOx drinks resulted in elevated plasma NOx concentration, but intake of low NOx drinks did not change the plasma NOx concentration. Based on these findings, a steady state could be achieved by 18 hours fasting after the intake of a moderately NOx-restricted diet (about 370, micromoles/day) and by 13 hours fasting after the intake of an extremely NOx-restricted diet (< 100 micromoles/day). NOx concentrations in randomly collected blood samples without these conditions were sometimes ten times higher than that at steady state. This procedure can be undertaken under normal Japanese daily life and is expected to be applicable even to outpatients.
NASA Technical Reports Server (NTRS)
Alfven, H.
1986-01-01
Traditionally the views on the cosmic environent have been based on observations in the visual octave of the electromagnetic spectrum, during the last half-century supplemented by infrared and radio observations. Space research has opened the full spectrum. Of special importance are the X-ray-gamma-ray regions, in which a number of unexpected phenomena have been discovered. Radiations in these regions are likely to originate mainly from magnetised cosmic plasmas. Such a medium may also emit synchrotron radiation which is observable in the radio region. If a model of the universe is based on the plasma phenomena mentioned it is found that the plasma universe is drastically different from the traditional visual universe. Information about the plasma universe can also be obtained by extrapolation of laboratory experiments and magnetospheric in situ measurements of plasmas. This approach is possible because it is likely that the basic properties of plasmas are the same everywhere. In order to test the usefulness of the plasma universe model it is applied to cosmogony. Such an approach seems to be rather successful. For example, the complicated structure of the Saturnian C ring can be accounted for. It is possible to reconstruct certain phenomena 4 to 5 billions of years ago with an accuracy of better than 1%.
Ishibashi, Takaharu; Miwa, Tomoko; Nishizawa, Naoki; Shinkawa, Ikumi; Yoshida, Junko; Kawada, Tomie; Nishio, Matomo
2011-01-01
The regulatory role of plasma nitrosothiols (R-SNOs) under steady-state conditions and their possible contribution to pharmacological vasodilation were systematically examined in anesthetized rabbits. Nitrosocystein (Cys-NO), S-nitrosoglutathione (G-SNO), and S-nitrosoalbumin (Alb-SNO) were determined by HPLC-Saville's method with respective sensitivities of 1, 1, and 5 nM. These R-SNOs were not detected under steady-state conditions even in the presence of N-ethylmaleimide, a thiol protective agent used to prevent transnitrosation of R-SNOs. Development of plasma Alb-SNO below 300 nM was observed after intravenous injection (i.v.) of nitric oxide (NO) solution (0.1 to 3 ml/g), NOC7 (an NO releasing agent, above 1 µg/kg), and a low dose of Alb-SNO (10 nmol/kg). However, blood pressure was not significantly reduced by NO solution or Alb-SNO. Intravenous injection of a high dose of Alb-SNO (300 nmol/kg) significantly reduced blood pressure with the appearance not only Alb-SNO in micromolar level in plasma, but also G-SNO in lesser degree. Conversely, the hypotensive effect of Cys-NO (300 nmol/kg, i.v.) and G-SNO (300 nmol/kg, i.v.) accompanied development of Alb-SNO (micromolar level), but not Cys-NO or G-SNO in plasma. R-SNOs were not found in plasma during profound hypotension induced by acetylcholine (10 and 30 µg/kg/min, continuous i.v.), glyceryl trinitrate (100 µg/kg, i.v.), sodium nitroprusside (100 µg/kg, i.v.), and isosorbide dinitrate (300 µg/kg, i.v.). These results indicate that R-SNOs do not play an important role under unstimulated condition. In addition, plasma R-SNOs may not be involved in pharmacological vasodilation where contributions of NO or R-SNOs are suggested.
Lundh, O; Rechatin, C; Faure, J; Ben-Ismaïl, A; Lim, J; De Wagter, C; De Neve, W; Malka, V
2012-06-01
To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research. © 2012 American Association of Physicists in Medicine.
Lundh, O.; Rechatin, C.; Faure, J.; Ben-Ismaiel, A.; Lim, J.; De Wagter, C.; De Neve, W.; Malka, V.
2012-06-15
Purpose: To evaluate the dose distribution of a 120-MeV laser-plasma accelerated electron beam which may be of potential interest for high-energy electron radiation therapy. Methods: In the interaction between an intense laser pulse and a helium gas jet, a well collimated electron beam with very high energy is produced. A secondary laser beam is used to optically control and to tune the electron beam energy and charge. The potential use of this beam for radiation treatment is evaluated experimentally by measurements of dose deposition in a polystyrene phantom. The results are compared to Monte Carlo simulations using the geant4 code. Results: It has been shown that the laser-plasma accelerated electron beam can deliver a peak dose of more than 1 Gy at the entrance of the phantom in a single laser shot by direct irradiation, without the use of intermediate magnetic transport or focusing. The dose distribution is peaked on axis, with narrow lateral penumbra. Monte Carlo simulations of electron beam propagation and dose deposition indicate that the propagation of the intense electron beam (with large self-fields) can be described by standard models that exclude collective effects in the response of the material. Conclusions: The measurements show that the high-energy electron beams produced by an optically injected laser-plasma accelerator can deliver high enough dose at penetration depths of interest for electron beam radiotherapy of deep-seated tumors. Many engineering issues must be resolved before laser-accelerated electrons can be used for cancer therapy, but they also represent exciting challenges for future research.
NASA Astrophysics Data System (ADS)
Sobel'man, Igor I.; Shevelko, A. P.; Yakushev, O. F.; Knight, L. V.; Turley, R. S.
2003-01-01
The results of investigation of a capillary discharge plasma, used as a source of intense VUV radiation and soft X-rays, are presented. The plasma was generated during the discharge of low-inductance condensers in a gas-filled ceramic capillary. Intense line radiation was observed in a broad spectral range (30-400 Å) in various gases (CO2, Ne, Ar, Kr, Xe). The absolute radiation yield for the xenon discharge was ~5 mJ (2π sr)-1 pulse-1 within a spectral band of width 9 Å at 135 Å. Such a radiation source can be used for various practical applications, such as EUV projection lithography, microscopy of biological objects in a 'water window', reflectometry, etc.
Svensen, Christer H; Stankevičius, Edgaras; Broms, Jacob; Markevičius, Vytautas; Andrijauskas, Audrius
2014-01-01
A mini volume loading test (mVLT) was proposed for estimating hydration status and interstitial fluid accumulation during stepwise infusion of crystalloids. The method is based on both the transcapillary reflux model and the hypothesis that when subjects are dehydrated, venous plasma dilution induced by a fluid challenge is higher than in the capillaries, and that difference is diminished when the fluid challenge is given to more hydrated individuals. Our objective was to test that hypothesis by evaluating the veno-capillary dilution difference during mVLT in subjects with different hydration status. In a prospective randomized crossover study, three mini fluid challenges were given to 12 healthy volunteers on two occasions. The subjects were either dehydrated or hydrated before the experiments. In dehydrated subjects only, capillary plasma dilution was significantly lower than venous (P=0.015, 0.005 and 0.006) after each mini fluid challenge. Veno-capillary dilution difference during mVLT depends on the hydration status. The mVLT method could possibly discriminate between the different states of hydration. Copyright © 2014 Lithuanian University of Health Sciences. Production and hosting by Elsevier Urban & Partner Sp. z o.o. All rights reserved.
Binary collision rates of relativistic thermal plasmas. I Theoretical framework
NASA Technical Reports Server (NTRS)
Dermer, C. D.
1985-01-01
Binary collision rates for arbitrary scattering cross sections are derived in the case of a beam of particles interacting with a Maxwell-Boltzmann (MB) plasma, or in the case of two MB plasmas interacting at generally different temperatures. The expressions are valid for all beam energies and plasma temperatures, from the nonrelativistic to the extreme relativistic limits. The calculated quantities include the reaction rate, the energy exchange rate, and the average rate of change of the squared transverse momentum component of a monoenergetic particle beam as a result of scatterings with particles of a MB plasma. Results are specialized to elastic scattering processes, two-temperature reaction rates, or the cold plasma limit, reproducing previous work.
Binary collision rates of relativistic thermal plasmas. I Theoretical framework
NASA Technical Reports Server (NTRS)
Dermer, C. D.
1985-01-01
Binary collision rates for arbitrary scattering cross sections are derived in the case of a beam of particles interacting with a Maxwell-Boltzmann (MB) plasma, or in the case of two MB plasmas interacting at generally different temperatures. The expressions are valid for all beam energies and plasma temperatures, from the nonrelativistic to the extreme relativistic limits. The calculated quantities include the reaction rate, the energy exchange rate, and the average rate of change of the squared transverse momentum component of a monoenergetic particle beam as a result of scatterings with particles of a MB plasma. Results are specialized to elastic scattering processes, two-temperature reaction rates, or the cold plasma limit, reproducing previous work.
Eigenfrequencies of a bounded plasma with non-uniform density along the boundary
NASA Astrophysics Data System (ADS)
Gradov, O. M.; Stenflo, L.
1984-05-01
The electrostatic surface waves in a cold bounded plasma have been studied for the case where the plasma density is non-uniform in a direction which is parallel to the boundary. It is shown that the eigenmode spectrum then is discrete. The eigenfrequencies, which are functions of the density gradient, are calculated for plane as well as cylindrical geometries. Special attention is paid to the particular case where the density profile is linear.
Sun, Yu; Liu, Yanan; Li, Rui; Xue, Gang; Ognier, Stéphanie
2016-07-01
This study investigated the degradation of a model organic compound, reactive blue (RB-19), in aqueous solution using a needle-plate non-thermal plasma (NTP) reactor, which was operated using three gas atmospheres (Ar, air, O2) at room temperature and atmospheric pressure. The relative discharge and degradation parameters, including the peak to peak applied voltage, power, ozone generation, pH, decolorization rates, energy density and the total organic carbon (TOC) reduction were analyzed to determine the various dye removal efficiencies. The decolorization rate for Ar, air and O2 were 59.9%, 49.6% and 89.8% respectively at the energy density of 100 kJ/L. The best TOC reduction was displayed by Ar with about 8.8% decrease, and 0% with O2 and air atmospheres. This phenomenon could be explained by the formation of OH• and O3 in the Ar and O2 atmospheres, which are responsible for increased mineralization and efficient decolorization. A one-dimension model was developed using software COMSOL to simulate the RB-19-ozone reaction and verify the experiments by comparing the simulated and experimental results. It was determined that ozone plays the most important role in the dye removal process, and the ozone contribution rate ranged from 0.67 to 0.82.
Kopittke, Peter M.; Blamey, F. Pax C.; Wang, Peng; Menzies, Neal W.
2011-01-01
Manganese (Mn) is an essential micronutrient for plant growth but is often toxic in acid or waterlogged soils. Using cowpea (Vigna unguiculata L. Walp.) grown with 0.05–1500 μM Mn in solution, two short-term (48 h) solution culture experiments examined if the effects of cations (Ca, Mg, Na, Al, or H) on Mn nutrition are related to the root cells’ plasma membrane (PM) surface potential, ψ00. When grown in solutions containing levels of Mn that were toxic, both relative root elongation rate (RRER) and root tissue Mn concentration were more closely related to the activity of Mn2+ at the outer surface of the PM, {Mn2+}00 (R2=0.812 and 0.871) than to its activity in the bulk solution, {Mn2+}b (R2=0.673 and 0.769). This was also evident at lower levels of Mn (0.05–10 μM) relevant to studies investigating Mn as an essential micronutrient (R2=0.791 versus 0.590). In addition, changes in the electrical driving force for ion transport across the PM influenced both RRER and the Mn concentration in roots. The {Mn2+}b causing a 50% reduction in root growth was found to be c. 500 to >1000 μM (depending upon solution composition), whilst the corresponding value was 3300 μM when related to {Mn2+}00. Although specific effects such as competition are not precluded, the data emphasize the importance of non-specific electrostatic effects in the Mn nutrition of cowpea seedlings over a 1×105-fold range of Mn concentration in solution. PMID:21511910
ERIC Educational Resources Information Center
Ayoub, Ayoub B.
2006-01-01
In this article, the author takes up the special trinomial (1 + x + x[squared])[superscript n] and shows that the coefficients of its expansion are entries of a Pascal-like triangle. He also shows how to calculate these entries recursively and explicitly. This article could be used in the classroom for enrichment. (Contains 1 table.)
ERIC Educational Resources Information Center
Ayoub, Ayoub B.
2006-01-01
In this article, the author takes up the special trinomial (1 + x + x[squared])[superscript n] and shows that the coefficients of its expansion are entries of a Pascal-like triangle. He also shows how to calculate these entries recursively and explicitly. This article could be used in the classroom for enrichment. (Contains 1 table.)
ERIC Educational Resources Information Center
Braswell, Ray, Ed.
This document contains the following papers on special needs instruction and technology: (1) "Hawaii Special Education Teacher Induction" (Kalena Oliva and Quinn Avery); (2) "The Impact of Group v Individual Use of Hypermedia-Based Instruction" (Lewis R. Johnson, Louis P. Semrau, and Gail E. Fitzgerald); (3) "Assistive…
Fang, Ferric C.
2014-01-01
As the body of scientific knowledge in a discipline increases, there is pressure for specialization. Fields spawn subfields that then become entities in themselves that promote further specialization. The process by which scientists join specialized groups has remarkable similarities to the guild system of the middle ages. The advantages of specialization of science include efficiency, the establishment of normative standards, and the potential for greater rigor in experimental research. However, specialization also carries risks of monopoly, monotony, and isolation. The current tendency to judge scientific work by the impact factor of the journal in which it is published may have roots in overspecialization, as scientists are less able to critically evaluate work outside their field than before. Scientists in particular define themselves through group identity and adopt practices that conform to the expectations and dynamics of such groups. As part of our continuing analysis of issues confronting contemporary science, we analyze the emergence and consequences of specialization in science, with a particular emphasis on microbiology, a field highly vulnerable to balkanization along microbial phylogenetic boundaries, and suggest that specialization carries significant costs. We propose measures to mitigate the detrimental effects of scientific specialism. PMID:24421049
Casadevall, Arturo; Fang, Ferric C
2014-04-01
As the body of scientific knowledge in a discipline increases, there is pressure for specialization. Fields spawn subfields that then become entities in themselves that promote further specialization. The process by which scientists join specialized groups has remarkable similarities to the guild system of the middle ages. The advantages of specialization of science include efficiency, the establishment of normative standards, and the potential for greater rigor in experimental research. However, specialization also carries risks of monopoly, monotony, and isolation. The current tendency to judge scientific work by the impact factor of the journal in which it is published may have roots in overspecialization, as scientists are less able to critically evaluate work outside their field than before. Scientists in particular define themselves through group identity and adopt practices that conform to the expectations and dynamics of such groups. As part of our continuing analysis of issues confronting contemporary science, we analyze the emergence and consequences of specialization in science, with a particular emphasis on microbiology, a field highly vulnerable to balkanization along microbial phylogenetic boundaries, and suggest that specialization carries significant costs. We propose measures to mitigate the detrimental effects of scientific specialism.
ERIC Educational Resources Information Center
Foskett, D. J.
The Special Library is distinguished from other libraries as being a library serving a particular group of readers, who have an existence as a group outside of their readership of the library, and whose members direct at least some of their activities towards a common purpose. Thus, the special librarian's first and major responsibility is to know…
NASA Astrophysics Data System (ADS)
Piron, R.; Blenski, T.
2011-02-01
The numerical code VAAQP (variational average atom in quantum plasmas), which is based on a fully variational model of equilibrium dense plasmas, is applied to equation-of-state calculations for aluminum, iron, copper, and lead in the warm-dense-matter regime. VAAQP does not impose the neutrality of the Wigner-Seitz ion sphere; it provides the average-atom structure and the mean ionization self-consistently from the solution of the variational equations. The formula used for the electronic pressure is simple and does not require any numerical differentiation. In this paper, the virial theorem is derived in both nonrelativistic and relativistic versions of the model. This theorem allows one to express the electron pressure as a combination of the electron kinetic and interaction energies. It is shown that the model fulfills automatically the virial theorem in the case of local-density approximations to the exchange-correlation free-energy. Applications of the model to the equation-of-state and Hugoniot shock adiabat of aluminum, iron, copper, and lead in the warm-dense-matter regime are presented. Comparisons with other approaches, including the inferno model, and with available experimental data are given. This work allows one to understand the thermodynamic consistency issues in the existing average-atom models. Starting from the case of aluminum, a comparative study of the thermodynamic consistency of the models is proposed. A preliminary study of the validity domain of the inferno model is also included.
Piron, R; Blenski, T
2011-02-01
The numerical code VAAQP (variational average atom in quantum plasmas), which is based on a fully variational model of equilibrium dense plasmas, is applied to equation-of-state calculations for aluminum, iron, copper, and lead in the warm-dense-matter regime. VAAQP does not impose the neutrality of the Wigner-Seitz ion sphere; it provides the average-atom structure and the mean ionization self-consistently from the solution of the variational equations. The formula used for the electronic pressure is simple and does not require any numerical differentiation. In this paper, the virial theorem is derived in both nonrelativistic and relativistic versions of the model. This theorem allows one to express the electron pressure as a combination of the electron kinetic and interaction energies. It is shown that the model fulfills automatically the virial theorem in the case of local-density approximations to the exchange-correlation free-energy. Applications of the model to the equation-of-state and Hugoniot shock adiabat of aluminum, iron, copper, and lead in the warm-dense-matter regime are presented. Comparisons with other approaches, including the inferno model, and with available experimental data are given. This work allows one to understand the thermodynamic consistency issues in the existing average-atom models. Starting from the case of aluminum, a comparative study of the thermodynamic consistency of the models is proposed. A preliminary study of the validity domain of the inferno model is also included. ©2011 American Physical Society
Plasma oscillations in spherical Gaussian shaped ultracold neutral plasma
Chen, Tianxing; Lu, Ronghua Guo, Li; Han, Shensheng
2016-04-15
The collective plasma oscillations are investigated in ultracold neutral plasma with a non-uniform density profile. Instead of the plane configuration widely used, we derive the plasma oscillation equations with spherically symmetric distribution and Gaussian density profile. The damping of radial oscillation is found. The Tonks–Dattner resonances of the ultracold neutral plasma with an applied RF field are also calculated.
ERIC Educational Resources Information Center
Humphreys, Casey; And Others
This valuable collection of materials was developed to incorporate the calculator as an instructional aid in ninth- and tenth-grade general and basic mathematics classes. The materials are also appropriate for grades 7 and 8. After an introductory section which teaches the use of the calculator, four games and activities are described. For these…
ERIC Educational Resources Information Center
Lavendel, Giuliana
1977-01-01
Discusses problems involved in maintaining special scientific or engineering libraries, including budget problems, remote storage locations, rental computer retrieval systems, protecting trade secrets, and establishing a magnetic tape library. (MLH)
Programmable calculator stress analysis
Van Gulick, L.A.
1983-01-01
This paper assesses the suitability of advanced programmable alphanumeric calculators for closed form calculation of pressure vessel stresses and offers, as their advantages, adequate computing power, portability, special programming features, and simple interactive execution procedures. Representative programs which demonstrate their capacities are presented. Problems dealing with stress and strength calculations in thick-walled pressure vessels and with the computation of stresses near head/pressure vessel junctures are treated. Assessed favorably in this paper as useful contributors to computeraided design of pressure vessels, programmable alphanumeric calculators have areas of implementation in checking finite element results, aiding in the development of an intuitive understanding of stresses and their parameter dependencies, and evaluating rapidly a variety of preliminary designs.
Calculating a Stepwise Ridge Regression.
ERIC Educational Resources Information Center
Morris, John D.
1986-01-01
Although methods for using ordinary least squares regression computer programs to calculate a ridge regression are available, the calculation of a stepwise ridge regression requires a special purpose algorithm and computer program. The correct stepwise ridge regression procedure is given, and a parallel FORTRAN computer program is described.…
Automatic calculation in quarkonium physics
NASA Astrophysics Data System (ADS)
Gong, Bin; Wan, Lu-Ping; Wang, Jian-Xiong; Zhang, Hong-Fei
2014-06-01
In this report, an automatic calculating package based on REDUCE and RLISP, FDC, is introduced, especially its one-loop calculation part and its special treatment for quarkonium physics. With FDC, many works have been completed, most of them are very important in solve/clarify current puzzles in quarkonium physics.
National Institute of Standards and Technology Data Gateway
SRD 166 MEMS Calculator (Web, free access) This MEMS Calculator determines the following thin film properties from data taken with an optical interferometer or comparable instrument: a) residual strain from fixed-fixed beams, b) strain gradient from cantilevers, c) step heights or thicknesses from step-height test structures, and d) in-plane lengths or deflections. Then, residual stress and stress gradient calculations can be made after an optical vibrometer or comparable instrument is used to obtain Young's modulus from resonating cantilevers or fixed-fixed beams. In addition, wafer bond strength is determined from micro-chevron test structures using a material test machine.
Cai, Hua-Lin; Wang, Feng; Li, Huan-De; Peng, Wen-Xing; Zhu, Rong-Hua; Deng, Yang; Jiang, Pei; Yan, Miao; Hu, Si-Miao; Lei, Su-Yun; Chen, Chang
2014-02-01
A liquid chromatography-tandem mass spectrometry method was developed and validated for the quantification of erythromycylamine, which is the predominant active metabolite of dirithromycin in human plasma. After solid-phase extraction, the analyte and internal standard (IS) were separated by using an isocratic mobile phase consisting of 20 mM ammonium acetate (pH 3.9, adjusted with formic acid)-acetonitrile (75:25, v/v) on a Phenyl-Hexyl column (150 × 2.1 mm, 3 μm) and then analyzed in positive ion mode under electrospray ionization. Azithromycin was selected as the IS because it has the most similar mass spectrometric and chromatographic behaviors to the analyte. The respective multiple reaction monitoring (MRM) transitions, m/z 368.5>83.2 for erythromycylamine and m/z 375.4>115.2 for IS were chosen to achieve high sensitivity and selectivity in determination. A more acidic mobile phase (pH 3.9) than those of previous reports and a special needle wash (ethylene glycol-acetonitrile-water, 50:30:20, v/v/v, adjusted to pH 3.9 using formic acid) were used to eliminate the carryover effects of the two macrolides. The method exhibited a linear dynamic range of 0.5-440.0 ng/mL for erythromycylamine in human plasma (r=0.9999). The lower limit of quantification (LLOQ) and limit of detection (LOD) were 0.5 and 0.05 ng/mL, respectively. The mean extraction recoveries were higher than 94.0% for the analyte and IS. The intra- and inter-day precisions ranged from 1.4 to 5.4% and from 1.6 to 4.0%, respectively. The accuracy varied between 91.2 and 101.2%. The established method was successfully applied to analyze the human plasma samples from 24 healthy subjects in a bioequivalence study of two dirithromycin enteric-coated formulations.
Plasma heating power dissipation in low temperature hydrogen plasmas
Komppula, J. Tarvainen, O.
2015-10-15
A theoretical framework for power dissipation in low temperature plasmas in corona equilibrium is developed. The framework is based on fundamental conservation laws and reaction cross sections and is only weakly sensitive to plasma parameters, e.g., electron temperature and density. The theory is applied to low temperature atomic and molecular hydrogen laboratory plasmas for which the plasma heating power dissipation to photon emission, ionization, and chemical potential is calculated. The calculated photon emission is compared to recent experimental results.
NASA Astrophysics Data System (ADS)
Sharma, Bikash; Kar, R.; Pal, Arup R.; Shilpa, R. K.; Dusane, R. O.; Patil, D. S.; Suryawanshi, S. R.; More, M. A.; Sinha, S.
2017-04-01
Carbon nanofibers (CNFs) and carbon nanotubes (CNTs) are grown on inconel substrates under two different experimental conditions using atmospheric pressure glow discharge radio-frequency (RF) PECVD process. A specially designed hollow cathode is used for this plasma generation. The growth is carried out at 610 and 660 °C substrate temperatures on inconel substrates. Our results show that CNFs and CNTs could be synthesized at 610 and 660 °C respectively irrespective of pre-treatment methods in either set. HRTEM results indicate that a temperature-induced transformation of CNFs into CNTs occur when the growth temperature is raised from 610 to 660 °C. With the help of characterization results and a schematic model, it is shown how an increase in hydrogen diffusion (~44% increase) plays a pivotal role in this transformation by providing a sink for hydrogen atoms. Field emission results show that most defective CNFs contribute to the maximum emission current density. This better field emission behavior is explained on the basis that the outer surfaces of CNFs are more defective due to the presence of the open edges of the graphene planes, which results in better field emission from the outer surfaces of the CNFs.
Calibration of the ISEE plasma composition experiment
NASA Technical Reports Server (NTRS)
Baugher, C. R.; Olsen, R. C.; Reasoner, D. L.
1986-01-01
The Plasma Composition experiment on the ISEE-1 satellite was designed to measure ions from 1 to 16 amu, at energies from near zero to 16 keV. The two nearly identical flight instruments were calibrated by means of preflight laboratory tests and in-flight data comparisons. This document presents most of the details of those efforts, with special emphasis on the low energy (0 to 100 eV) portion of the instrument response. The analysis of the instrument includes a ray-tracing calculation, which follows an ensemble of test particles through the detector.
High-performance simulations for atmospheric pressure plasma reactor
NASA Astrophysics Data System (ADS)
Chugunov, Svyatoslav
Plasma-assisted processing and deposition of materials is an important component of modern industrial applications, with plasma reactors sharing 30% to 40% of manufacturing steps in microelectronics production. Development of new flexible electronics increases demands for efficient high-throughput deposition methods and roll-to-roll processing of materials. The current work represents an attempt of practical design and numerical modeling of a plasma enhanced chemical vapor deposition system. The system utilizes plasma at standard pressure and temperature to activate a chemical precursor for protective coatings. A specially designed linear plasma head, that consists of two parallel plates with electrodes placed in the parallel arrangement, is used to resolve clogging issues of currently available commercial plasma heads, as well as to increase the flow-rate of the processed chemicals and to enhance the uniformity of the deposition. A test system is build and discussed in this work. In order to improve operating conditions of the setup and quality of the deposited material, we perform numerical modeling of the plasma system. The theoretical and numerical models presented in this work comprehensively describe plasma generation, recombination, and advection in a channel of arbitrary geometry. Number density of plasma species, their energy content, electric field, and rate parameters are accurately calculated and analyzed in this work. Some interesting engineering outcomes are discussed with a connection to the proposed setup. The numerical model is implemented with the help of high-performance parallel technique and evaluated at a cluster for parallel calculations. A typical performance increase, calculation speed-up, parallel fraction of the code and overall efficiency of the parallel implementation are discussed in details.
Woo, Kerry J; Elliott, Kyle Hamish; Davidson, Melissa; Gaston, Anthony J; Davoren, Gail K
2008-11-01
1. We studied chick diet in a known-age, sexed population of a long-lived seabird, the Brünnich's guillemot (Uria lomvia), over 15 years (N = 136; 1993-2007) and attached time-depth-temperature recorders to examine foraging behaviour in multiple years (N = 36; 2004-07). 2. Adults showed specialization in prey fed to offspring, described by multiple indices calculated over 15 years: 27% of diet diversity was attributable to among-individual variation (within-individual component of total niche width = 0.73); average similarity of an individual's diet to the overall diet was 65% (mean proportional similarity between individuals and population = 0.65); diet was significantly more specialized than expected for 70% of individuals (mean likelihood = 0.53). These indices suggest higher specialization than the average for an across-taxa comparison of 49 taxa. 3. Foraging behaviour varied along three axes: flight time, dive depth and dive shape. Individuals showed specialized individual foraging behaviour along each axis. These foraging strategies were reflected in the prey type delivered to their offspring and were maintained over scales of hours to years. 4. Specialization in foraging behaviour and diet was greater over short time spans (hours, days) than over long time spans (years). Regardless of sex or age, the main component of variation in foraging behaviour and chick diet was between individuals. 5. Plasma stable isotope values were similar across years, within a given individual, and variance was low relative to that expected from prey isotope values, suggesting adult diet specialized across years. Stable isotope values were similar among individuals that fed their nestlings similar prey items and there was no difference in trophic level between adults and chicks. We suggest that guillemots specialize on a single foraging strategy regardless of whether chick-provisioning and self-feeding. With little individual difference in body mass and physiology
10 CFR 766.102 - Calculation methodology.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 10 Energy 4 2014-01-01 2014-01-01 false Calculation methodology. 766.102 Section 766.102 Energy DEPARTMENT OF ENERGY URANIUM ENRICHMENT DECONTAMINATION AND DECOMMISSIONING FUND; PROCEDURES FOR SPECIAL ASSESSMENT OF DOMESTIC UTILITIES Procedures for Special Assessment § 766.102 Calculation methodology. (a...
10 CFR 766.102 - Calculation methodology.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 10 Energy 4 2013-01-01 2013-01-01 false Calculation methodology. 766.102 Section 766.102 Energy DEPARTMENT OF ENERGY URANIUM ENRICHMENT DECONTAMINATION AND DECOMMISSIONING FUND; PROCEDURES FOR SPECIAL ASSESSMENT OF DOMESTIC UTILITIES Procedures for Special Assessment § 766.102 Calculation methodology. (a...
10 CFR 766.102 - Calculation methodology.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 10 Energy 4 2011-01-01 2011-01-01 false Calculation methodology. 766.102 Section 766.102 Energy DEPARTMENT OF ENERGY URANIUM ENRICHMENT DECONTAMINATION AND DECOMMISSIONING FUND; PROCEDURES FOR SPECIAL ASSESSMENT OF DOMESTIC UTILITIES Procedures for Special Assessment § 766.102 Calculation methodology. (a...
10 CFR 766.102 - Calculation methodology.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 10 Energy 4 2012-01-01 2012-01-01 false Calculation methodology. 766.102 Section 766.102 Energy DEPARTMENT OF ENERGY URANIUM ENRICHMENT DECONTAMINATION AND DECOMMISSIONING FUND; PROCEDURES FOR SPECIAL ASSESSMENT OF DOMESTIC UTILITIES Procedures for Special Assessment § 766.102 Calculation methodology. (a...
10 CFR 766.102 - Calculation methodology.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 10 Energy 4 2010-01-01 2010-01-01 false Calculation methodology. 766.102 Section 766.102 Energy DEPARTMENT OF ENERGY URANIUM ENRICHMENT DECONTAMINATION AND DECOMMISSIONING FUND; PROCEDURES FOR SPECIAL ASSESSMENT OF DOMESTIC UTILITIES Procedures for Special Assessment § 766.102 Calculation methodology. (a...
ERIC Educational Resources Information Center
Vander Weele, Maribeth
1992-01-01
Thomas Hehir, special education chief of Chicago Public Schools, is evangelist of integrating children with disabilities into regular classrooms. By completely reorganizing department viewed as political patronage dumping ground, Hehir has made remarkable progress in handling large number of children awaiting evaluation and placement in special…
ERIC Educational Resources Information Center
Wiant, Sarah K.; Lynch, Clifford; Nevins, Kate; Juergens, Bonnie
1998-01-01
Contains three special reports: developments in copyright law, 1997 (World Intellectual Property Organization (WIPO) legislation, Ashcroft Bill, No Electronic Theft Act, database protection, Conference on Fair Use (CONFU), judicial decisions, principles for licensing electronic resources, and Uniform Commercial Code Article 2B); Internet2 and the…
ERIC Educational Resources Information Center
Cox, Gary B., Ed.
1994-01-01
The nine articles of this special section focus on the role of evaluation in the reform of the mental health system in Washington. The reform process is described from its inception through its design to the dissemination and utilization of evaluation results. The final article considers implications for statewide evaluations. (SLD)
ERIC Educational Resources Information Center
Young, Peter R.; And Others
1994-01-01
Includes six special reports: "Libraries and the National Information Infrastructure" (Peter R. Young and Jane Williams); "Library Cooperation and Networking" (JoAn Segal); "Mexican Information Resources in Electronic Format" (Shirley Ainsworth); "The International Role of U.S. Librarians" (Hannelore B.…
ERIC Educational Resources Information Center
Wiant, Sarah K.; Lynch, Clifford; Nevins, Kate; Juergens, Bonnie
1998-01-01
Contains three special reports: developments in copyright law, 1997 (World Intellectual Property Organization (WIPO) legislation, Ashcroft Bill, No Electronic Theft Act, database protection, Conference on Fair Use (CONFU), judicial decisions, principles for licensing electronic resources, and Uniform Commercial Code Article 2B); Internet2 and the…
ERIC Educational Resources Information Center
Vander Weele, Maribeth
1992-01-01
Thomas Hehir, special education chief of Chicago Public Schools, is evangelist of integrating children with disabilities into regular classrooms. By completely reorganizing department viewed as political patronage dumping ground, Hehir has made remarkable progress in handling large number of children awaiting evaluation and placement in special…
ERIC Educational Resources Information Center
Haycock, Ken; Chapin, Betty; Bruce, David; Durrance, Joan C.; Pettigrew, Karen; Oakley, Robert L.; Juergens, Bonnie; Nevins, Kate
1999-01-01
Presents these special reports: "Information Age Dilemma: Filtering the Internet for Young People"; "KALIPER: A Look at Library and Information Science Education at the Turn of a New Century"; "Copyright 1998: Recalibrating the Balance"; "Library Networking and Cooperation in 1998". (AEF)
Clark, A.; Curtis, A.B.; Darwin, W.N.
1981-01-01
Rotating cardboard discs are used to read off total tree or topwood firewood volume (tons or cords) that can be expected from trees of d.b.h. 6 to 24 inches and tree height 10 to 90 feet. One side of the calculator is used for broadleaved species with deliquescent crowns and the other side for braodleaves with excurrent crowns.
Albers, R.C.; Gubernatis, J.E.
1981-01-01
The efficiency of four different Brillouin-zone integration schemes including the uniform mesh, special point method, special directions method, and Holas method are compared for calculating moments of the harmonic phonon frequencies of the solid one-component plasma. Very accurate values for the moments are also presented. The Holas method for which weights and integration points can easily be generated has roughly the same efficiency as the special directions method, which is much superior to the uniform mesh and special point methods for this problem.
NASA Technical Reports Server (NTRS)
1994-01-01
MathSoft Plus 5.0 is a calculation software package for electrical engineers and computer scientists who need advanced math functionality. It incorporates SmartMath, an expert system that determines a strategy for solving difficult mathematical problems. SmartMath was the result of the integration into Mathcad of CLIPS, a NASA-developed shell for creating expert systems. By using CLIPS, MathSoft, Inc. was able to save the time and money involved in writing the original program.
NASA Astrophysics Data System (ADS)
Volokitin, G. G.; Skripnikova, N. K.; Sinitsyn, V. A.; Volokitin, O. G.; Shekhovtsov, V. V.; Vaschenko, S. P.; Kuz'min, V. I.
2016-01-01
Plasma technology was developed to create protective-decorative coatings on the wood surfaces. Experimental investigation on applying the protective coating using the low-temperature plasma energy as well as studies of the distribution of temperature fields over the section of the treated workpiece have been carried out, and the calculated results have been compared with the experimental data.
NASA Astrophysics Data System (ADS)
Wu, Yue; Cai, Yan; Sun, Dawei; Zhu, Junjie; Wu, Yixiong
2014-12-01
A novel lateral restraint method was proposed to suppress plasma plume of high power CO2 laser welding using a pair of copper blocks with cooling water. The plasma plume was observed with a high-speed camera, and its core zone and periphery zone were investigated based on the specific processing algorithm. With the specially designed shifting unit, the spectrum of plasma plume was scanned both in 1-D and 2-D mode. Based on the selected spectral lines, electron temperature and electron number density of plasma plume were calculated. The characteristics of plasma plume, as well as the restraint mechanism, were discussed both in 1-D and 2-D mode. Results showed that the cooling effect, blowing effect and the static pressure were enhanced by the lateral restraint, and the restraint effect of the near-wall low-temperature area limited the expansion of plasma plume greatly.
Hunter, Charles H.
2000-05-22
This software calculates a Wet Bulb Globe Temperature (WBGT) using standard measurements from a meteorological station. WBGT is used by Industrial Hygenists (IH) to determine heat stress potential to outdoor workers. Through the mid 1990''s, SRS technicians were dispatched several times daily to measure WBGT with a custom hand held instrument and results were dessiminated via telephone. Due to workforce reductions, the WSRC IH Department asked for the development of an automated method to simulate the WBGT measurement using existing real time data from the Atmospheric Technologies Group''s meteorological monitoring network.
Special issue on filamentation
NASA Astrophysics Data System (ADS)
Li, Ruxin; Milchberg, Howard; Mysyrowicz, André
2014-05-01
Journal of Physics B: Atomic, Molecular and Optical Physics is delighted to announce a forthcoming special issue on filamentation, to appear in the spring of 2015, and invites you to submit a paper. This special issue will attempt to give an overview of the present status of this field in order to create synergies and foster future developments. The issue is open to papers on the following issues: Theoretical advances on filamentation. Self-focusing and collapse. Filamentation in various media. Pulse self-compression and ultrafast processes in filaments. Molecular alignment and rotation. Filamentation tailoring. Interaction between filaments. Filament weather and pollution control. Filament induced condensation and precipitation. Terahertz science with filaments. Lasing in filaments. Filament induced molecular excitation and reaction. Electric discharge and plasma. Cross-disciplinary applications. Novel concepts related to these topics are particularly welcome. Please submit your article by 1 October 2014 (expected web publication: spring 2015) using our website http://mc04.manuscriptcentral.com/jphysb-iop. Submissions received after this date will be considered for the journal, but may not be included in the special issue. The issue will be edited by Ruxin Li, Howard Milchberg and André Mysyrowicz.
Investigation of nonideal plasma properties
NASA Astrophysics Data System (ADS)
Wilhelm, H. E.
1981-05-01
The electrical conductivity of nonideal classical and quantum plasmas is calculated by means of dimensional analysis, kinetic theory, and quantum field theoretical methods. The new conductivity formulas are compared with recent experimental conductivity data for nonideal alkali plasmas. A theory of the electric microfield distribution in thermal plasmas and the anomalous microfield driven diffusion of charged particles across magnetic fields is presented, which is applicable only to ideal and weakly nonideal plasmas. By means of Bose statistics, the free energy of the random, thermally excited (longitudinal) electron and ion waves (collective many-body interactions) are calculated, and their quantitative relation to the free energy of nonideal plasmas is discussed.
NASA Astrophysics Data System (ADS)
von Woedtke, Th.; Reuter, S.; Masur, K.; Weltmann, K.-D.
2013-09-01
Plasma medicine is an innovative and emerging field combining plasma physics, life science and clinical medicine. In a more general perspective, medical application of physical plasma can be subdivided into two principal approaches. (i) “Indirect” use of plasma-based or plasma-supplemented techniques to treat surfaces, materials or devices to realize specific qualities for subsequent special medical applications, and (ii) application of physical plasma on or in the human (or animal) body to realize therapeutic effects based on direct interaction of plasma with living tissue. The field of plasma applications for the treatment of medical materials or devices is intensively researched and partially well established for several years. However, plasma medicine in the sense of its actual definition as a new field of research focuses on the use of plasma technology in the treatment of living cells, tissues, and organs. Therefore, the aim of the new research field of plasma medicine is the exploitation of a much more differentiated interaction of specific plasma components with specific structural as well as functional elements or functionalities of living cells. This interaction can possibly lead either to stimulation or inhibition of cellular function and be finally used for therapeutic purposes. During recent years a broad spectrum of different plasma sources with various names dedicated for biomedical applications has been reported. So far, research activities were mainly focused on barrier discharges and plasma jets working at atmospheric pressure. Most efforts to realize plasma application directly on or in the human (or animal) body for medical purposes is concentrated on the broad field of dermatology including wound healing, but also includes cancer treatment, endoscopy, or dentistry. Despite the fact that the field of plasma medicine is very young and until now mostly in an empirical stage of development yet, there are first indicators of its enormous
How to Patch Active Plasma and Collisionless Sheath: Practical Guide
Kaganovich, Igor D.
2002-08-22
Most plasmas have a very thin sheath compared with the plasma dimension. This necessitates separate calculations of the plasma and sheath. The Bohm criterion provides the boundary condition for calculation of plasma profiles. To calculate sheath properties, a value of electric field at the plasma-sheath interface has to be specified in addition to the Bohm criterion. The value of the boundary electric field and robust procedure to approximately patch plasma and collisionless sheath with a very good accuracy are reported.
Electric Calculators; Business Education: 7718.06.
ERIC Educational Resources Information Center
McShane, Jane
The course was developed to instruct students in the use of mechanical and/or electronic printing calculators, electronic display calculators, and rotary calculators to solve special business problems with occupational proficiency. Included in the document are a list of performance objectives, a course content outline, suggested learning…
Decimals, Denominators, Demons, Calculators, and Connections
ERIC Educational Resources Information Center
Sparrow, Len; Swan, Paul
2005-01-01
The authors provide activities for overcoming some fraction misconceptions using calculators specially designed for learners in primary years. The writers advocate use of the calculator as a way to engage children in thinking about mathematics. By engaging with a calculator as part of mathematics learning, children are learning about and using the…
46 CFR 174.360 - Calculations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 46 Shipping 7 2010-10-01 2010-10-01 false Calculations. 174.360 Section 174.360 Shipping COAST... SPECIFIC VESSEL TYPES Special Rules Pertaining to Dry Cargo Ships § 174.360 Calculations. Each ship to... II-1, part B-1. Compliance with the applicable requirements must be demonstrated by calculations...
The plasma environment of comets
Gombosi, T.I. )
1991-01-01
U.S. research activities in the area of cometary plasma physics during 1987-1990 are reviewed. Consideration is given to mass loading and its consequences in the upstream region, the cometary shock, the cometosheath, the diamagnetic cavity boundary and the inner shock, and the plasma tail. Special attention is given to models and observations that have modified the pre-encounter understanding of cometary plasma environments. 211 refs.
Radiative electron capture in nonequilibrium plasmas
Milchberg, H.M.; Weisheit, J.C.
1982-01-19
Formulae have been obtained for the degree of linear polarization of recombination radiation from a homogeneous plasma having an anisotropic electron velocity distribution, f(v vector), characterized by an axis of symmetry. Polarization measurements are described which utilize these formulae to determine aspects of the anisotropy such as the symmetry axis direction and the lowest order even angular moments of f(v vector). As a special case, if the plasma conforms to a distribution such as a bi-Maxwellian with drift, one can determine the quantities u/sub D//T/sub parallel to/ and (1/T/sub parallel to/ - 1/T/sub perpendicular to/) which involve the electron drift speed, and the perpendicular and parallel electron temperatures. Also, the radiative recombination rate has been calculated for ions whose speeds are comparable to or greater than the electron thermal speed. The change in the rate is small for thermonuclear products in fusion plasmas, but large for cosmic rays in interstellar plasma.
Andreasen, F; Jakobsen, P; Kornerup, H J; Pedersen, E B; Pedersen, O L
1983-01-01
Eight hypertensive patients who had been followed in an outpatient clinic during long-term therapy with propranolol (40 to 160 mg twice daily) were studied during a 24-hr stay in the ward. The usual oral dose was given and the total and free plasma concentrations were determined during the 24 hr and the urinary excretion of unchanged drug was measured. Average free plasma concentration of propranolol (y free) was calculated from: y free = Excreted propranolol (ng/24 hr)/Creatinine clearance (ml/24 hr). There was a significant relationship between log y free and average free plasma concentration (means free) determined from the directly measured plasma concentration curve: log y free = 0.0743 means free - 0.0466 (r = 0.98, P less than 0.001). In another group of propranolol-treated hypertensive patients there was a significant positive relationship between orosomucoid concentration and reciprocal of the free propranolol fraction in plasma. From this relationship the average total drug concentration (y total) was calculated from y free; there was a significant correlation with directly measured total plasma level: log y total = 0.0038 . means total + 1.0895 (r = 0.91, P less than 0.001). It is suggested that individually determined values of y free below 30 ng/ml and y total below 400 ng/ml (the concentration range studied) can be used to calculate the average mean 24-hr free and total plasma concentrations.
Propagation of an atmospheric pressure plasma plume
NASA Astrophysics Data System (ADS)
Lu, X.; Xiong, Q.; Xiong, Z.; Hu, J.; Zhou, F.; Gong, W.; Xian, Y.; Zou, C.; Tang, Z.; Jiang, Z.; Pan, Y.
2009-02-01
The "plasma bullet" behavior of atmospheric pressure plasma plumes has recently attracted significant interest. In this paper, a specially designed plasma jet device is used to study this phenomenon. It is found that a helium primary plasma can propagate through the wall of a dielectric tube and keep propagating inside the dielectric tube (secondary plasma). High-speed photographs show that the primary plasma disappears before the secondary plasma starts to propagate. Both plumes propagate at a hypersonic speed. Detailed studies on the dynamics of the plasma plumes show that the local electric field induced by the charges on the surface of the dielectric tube plays an important role in the ignition of the secondary plasma. This indicates that the propagation of the plasma plumes may be attributed to the local electric field induced by the charges in the bulletlike plasma volume.
Propagation of an atmospheric pressure plasma plume
Lu, X.; Xiong, Q.; Xiong, Z.; Hu, J.; Zhou, F.; Gong, W.; Xian, Y.; Zou, C.; Tang, Z.; Jiang, Z.; Pan, Y.
2009-02-15
The ''plasma bullet'' behavior of atmospheric pressure plasma plumes has recently attracted significant interest. In this paper, a specially designed plasma jet device is used to study this phenomenon. It is found that a helium primary plasma can propagate through the wall of a dielectric tube and keep propagating inside the dielectric tube (secondary plasma). High-speed photographs show that the primary plasma disappears before the secondary plasma starts to propagate. Both plumes propagate at a hypersonic speed. Detailed studies on the dynamics of the plasma plumes show that the local electric field induced by the charges on the surface of the dielectric tube plays an important role in the ignition of the secondary plasma. This indicates that the propagation of the plasma plumes may be attributed to the local electric field induced by the charges in the bulletlike plasma volume.
Cayzac, W; Bagnoud, V; Basko, M M; Blažević, A; Frank, A; Gericke, D O; Hallo, L; Malka, G; Ortner, A; Tauschwitz, An; Vorberger, J; Roth, M
2015-11-01
The energy loss of light ions in dense plasmas is investigated with special focus on low to medium projectile energies, i.e., at velocities where the maximum of the stopping power occurs. In this region, exceptionally large theoretical uncertainties remain and no conclusive experimental data are available. We perform simulations of beam-plasma configurations well suited for an experimental test of ion energy loss in highly ionized, laser-generated carbon plasmas. The plasma parameters are extracted from two-dimensional hydrodynamic simulations, and a Monte Carlo calculation of the charge-state distribution of the projectile ion beam determines the dynamics of the ion charge state over the whole plasma profile. We show that the discrepancies in the energy loss predicted by different theoretical models are as high as 20-30%, making these theories well distinguishable in suitable experiments.
NASA Astrophysics Data System (ADS)
Sosedkin, A. P.; Lotov, K. V.
2016-09-01
LCODE is a freely distributed quasistatic 2D3V code for simulating plasma wakefield acceleration, mainly specialized at resource-efficient studies of long-term propagation of ultrarelativistic particle beams in plasmas. The beam is modeled with fully relativistic macro-particles in a simulation window copropagating with the light velocity; the plasma can be simulated with either kinetic or fluid model. Several techniques are used to obtain exceptional numerical stability and precision while maintaining high resource efficiency, enabling LCODE to simulate the evolution of long particle beams over long propagation distances even on a laptop. A recent upgrade enabled LCODE to perform the calculations in parallel. A pipeline of several LCODE processes communicating via MPI (Message-Passing Interface) is capable of executing multiple consecutive time steps of the simulation in a single pass. This approach can speed up the calculations by hundreds of times.
Foster, J.S. Jr.
1958-03-11
This patent describes apparatus for producing an electricity neutral ionized gas discharge, termed a plasma, substantially free from contamination with neutral gas particles. The plasma generator of the present invention comprises a plasma chamber wherein gas introduced into the chamber is ionized by a radiofrequency source. A magnetic field is used to focus the plasma in line with an exit. This magnetic field cooperates with a differential pressure created across the exit to draw a uniform and uncontaminated plasma from the plasma chamber.
Goates, J.J.; Morton, K.A.; Whooten, W.W.; Greenberg, H.E.; Datz, F.L.; Handy, J.E.; Scuderi, A.J.; Haakenstad, A.O.; Lynch, R.E. )
1990-04-01
True glomerular filtration rate (GFR) was measured in normal volunteers and in patients with normal and impaired renal function by the iothalamate clearance (IC) method of Sigman. Within 24 hr, GFR was also determined by two other methods: technetium-99m- ({sup 99m}Tc) DTPA scintigraphic analysis (SA) utilizing a modification of the Gates computer program, and by measuring disappearance of {sup 99m}Tc-DTPA from whole plasma (WPC) and from protein-free ultrafiltered plasma (PFPC). Determinations of GFR by IC and by PFPC methods were virtually identical (mean absolute error 5.36 ml/min, r = 0.99, p greater than 0.05). GFRs measured in protein-free, ultrafiltered plasma differed significantly from those obtained from whole plasma only in sicker patients and in those taking multiple medications (in whom alterations in protein-binding of DTPA may be seen). The SA method correlated less well with the iodine-125-({sup 125}I) IC method than did either the protein-free or whole-plasma clearance methods (mean absolute error 32.36 ml/min, r = 0.74, p less than 0.05). However, the SA method provided useful information with respect to differential (split) renal function.
Eligon, A M; Gruber, N; Silfvast, W T
1995-08-01
We describe a special filter design that produces spectrally narrow soft-x-ray radiation by using a broadband laser-produced plasma source and multilayer-coated reflecting optics. Calculations for the design were carried out at several laser-produced plasma-source temperatures and various multilayermirror combinations with and without a soft-x-ray filter. We determined that the best arrangement for a laser-produced plasma source consists of two multilayer mirrors and one soft-x-ray filter for each temperature investigated.
Analysis of nuclear induced plasmas
NASA Technical Reports Server (NTRS)
Deese, J. E.; Hassan, H. A.
1976-01-01
A kinetic model is developed for a plasma generated by fission fragments, and the results are employed to study He plasma generated in a tube coated with fissionable material. Because both the heavy particles and electrons play important roles in creating the plasma, their effects are considered simultaneously. The calculations are carried out for a range of neutron fluxes and pressures. In general, the predictions of the theory are in good agreement with available intensity measurements. Moreover, the theory predicts the experimentally measured inversions. However, the calculated gain coefficients are such that lasing is not expected to take place in a helium plasma generated by fission fragments.
EDITORIAL: Plasma jets and plasma bullets Plasma jets and plasma bullets
NASA Astrophysics Data System (ADS)
Kong, M. G.; Ganguly, B. N.; Hicks, R. F.
2012-06-01
-mentioned early studies has witnessed a considerable and exciting growth in terms of new phenomena observed, new physics and chemistry uncovered, new plasma jet sources conceived, and new applications developed. Examples include the observations of plasma bullets on a nanosecond scale [16], the similarity of plasma bullets to streamers [17], arrays of plasma jets as metamaterials [18], and a rapid increase of applications in biomedicine [19]. However the considerable growth in the research of plasma jets has not been adequately supported, so far, by a sound fundamental underpinning, partly resulting from a somewhat underdevelopment of effective diagnostics and modelling tools. Recognizing the critical importance of basic science for future growth of low-temperature plasma jet technology, this special issue on plasma jets and bullets aims to address some of the most important fundamental questions. Many of the special issue papers continue the established line of investigation to characterize the formation of plasma bullets, using typically ultrafast imaging, electrical detection including electric field and plasma conductivity measurement, and optical emission spectrometry [20]-[26]. These offer strong experimental evidence for the well-known hypothesis that a plasma jet is a form of streamer, and that the ionization wave plays a critical role in their formation. The interaction of two parallel plasma jets [27] and manipulation of plasma jet characteristics [28, 29] are also reported using a similar combination of experimental techniques. Some of the common characteristics of plasma jets are summarized in a review paper in this special issue [30]. A somewhat different line of investigation is employed in a detailed experimental characterization of deterministic chaos in atmospheric plasma jets [31], one of the few non-bullet modes of plasma jets. Although chaos in ionized gases have been observed in other types of discharge plasmas, their applications have not so far been linked
Wakes in Inertial Fusion Plasmas
NASA Astrophysics Data System (ADS)
Ellis, Ian Norman
Plasma wave wakes, which are the collective oscillatory response near the plasma frequency to the propagation of particles or electromagnetic waves through a plasma, play a critical role in many plasma processes. New results from backwards stimulated Raman scattering (BSRS), in which wakes with phase velocities much less than the speed of light are induced by the beating of counter-propagating light waves, and from electron beam stopping, in which the wakes are produced by the motion of relativistically propagating electrons through the dense plasma, are discussed. Both processes play important roles in Inertial Confinement Fusion (ICF). In BSRS, laser light is scattered backwards out of the plasma, decreasing the energy available to compress the ICF capsule and affecting the symmetry of where the laser energy hits the hohlraum wall in indirect drive ICF. The plasma wave wake can also generate superthermal electrons that can preheat the core and/or the ablator. Electron beam stopping plays a critical role in the Fast Ignition (FI) ICF concept, in which a beam of relativistic electrons is used to heat the target core to ignition temperatures after the compression stage. The beam stopping power determines the effectiveness of the heating process. This dissertation covers new discoveries on the importance of plasma wave wakes in both BSRS and electron beam stopping. In the SRS studies, 1D particle-in-cell (PIC) simulations using OSIRIS are performed, which model a short-duration (˜500/ω0 --1FWHM) counter-propagating scattered light seed pulse in the presence of a constant pump laser with an intensity far below the absolute instability threshold for plasma waves undergoing Landau damping. The seed undergoes linear convective Raman amplification and dominates over the amplification of fluctuations due to particle discreteness. The simulation results are in good agreement with results from a coupled-mode solver when special relativity and the effects of finite size PIC
40 CFR 405.91 - Specialized definitions.
Code of Federal Regulations, 2011 CFR
2011-07-01
... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.91 Specialized... can be calculated by multiplying the fats, proteins and carbohydrates by factors of 0.890, 1.031 and...
40 CFR 405.91 - Specialized definitions.
Code of Federal Regulations, 2013 CFR
2013-07-01
... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.91 Specialized... can be calculated by multiplying the fats, proteins and carbohydrates by factors of 0.890, 1.031 and...
40 CFR 405.91 - Specialized definitions.
Code of Federal Regulations, 2014 CFR
2014-07-01
... STANDARDS DAIRY PRODUCTS PROCESSING POINT SOURCE CATEGORY Condensed Milk Subcategory § 405.91 Specialized... can be calculated by multiplying the fats, proteins and carbohydrates by factors of 0.890, 1.031 and...
Quantitative diagnostics of reactive, multicomponent low-temperature plasmas
NASA Astrophysics Data System (ADS)
Schwarz-Selinger, Thomas
2013-09-01
The special emphasis in this work is put on the quantitative determination of the plasma composition of an inductively coupled low temperature plasma (ICP). Several standard plasma diagnostic techniques were applied. As a test case for a multi-component low-temperature plasma argon-hydrogen as well as argon-hydrogen-nitrogen mixed plasmas were investigated. For steady-state plasma operation the ion density and electron temperature were determined with a single tip Langmuir probe. A multi-grid miniature retarding-field analyzer was used to measure the mass integrated ion flux. An energy-dispersive mass spectrometer - a so-called plasma monitor (PM) - was applied to sample ions from the plasma to derive the ion composition. The degree of dissociation of hydrogen and the gas temperature were derived from optical emission spectroscopy. The gas temperature was estimated by the rotational distribution of the Q-branch lines of the hydrogen Fulcher- α diagonal band for the argon-hydrogen mixed plasmas and from the second positive system of N2 in argon-hydrogen-nitrogen mixed plasmas. The degree of dissociation of hydrogen was measured by actinometry. The influence of the substrate material of the counter electrode (stainless steel, copper, tungsten, Macor, and aluminium) on the atomic hydrogen concentration was investigated by OES. In addition, ionization-threshold mass spectrometry (ITMS) was used to determine the densities of atomic nitrogen (N) and atomic hydrogen (H and D). Pulsed plasma operation was applied to directly measure the loss rate of H, D and N in the afterglow from the temporal decay of the ITMS signal. From these data the wall loss probability of atomic hydrogen was determined. Furthermore, a zero-dimensional rate equation model was devised to explain the ion composition in these mixed plasmas with different admixture ratios. In addition to the experimental data on electron density, gas temperature, total pressure, atomic hydrogen density, and Ar, H2
Plasma generating apparatus for large area plasma processing
Tsai, C.C.; Gorbatkin, S.M.; Berry, L.A.
1991-07-16
A plasma generating apparatus for plasma processing applications is based on a permanent magnet line-cusp plasma confinement chamber coupled to a compact single-coil microwave waveguide launcher. The device creates an electron cyclotron resonance (ECR) plasma in the launcher and a second ECR plasma is created in the line cusps due to a 0.0875 tesla magnetic field in that region. Additional special magnetic field configuring reduces the magnetic field at the substrate to below 0.001 tesla. The resulting plasma source is capable of producing large-area (20-cm diam), highly uniform (.+-.5%) ion beams with current densities above 5 mA/cm[sup 2]. The source has been used to etch photoresist on 5-inch diam silicon wafers with good uniformity. 3 figures.
Plasma generating apparatus for large area plasma processing
Tsai, Chin-Chi; Gorbatkin, Steven M.; Berry, Lee A.
1991-01-01
A plasma generating apparatus for plasma processing applications is based on a permanent magnet line-cusp plasma confinement chamber coupled to a compact single-coil microwave waveguide launcher. The device creates an electron cyclotron resonance (ECR) plasma in the launcher and a second ECR plasma is created in the line cusps due to a 0.0875 tesla magnetic field in that region. Additional special magnetic field configuring reduces the magnetic field at the substrate to below 0.001 tesla. The resulting plasma source is capable of producing large-area (20-cm diam), highly uniform (.+-.5%) ion beams with current densities above 5 mA/cm.sup.2. The source has been used to etch photoresist on 5-inch diam silicon wafers with good uniformity.
A new small microwave plasma torch
NASA Astrophysics Data System (ADS)
Stonies, Robert; Schermer, Susanne; Voges, Edgar; Broekaert, José A. C.
2004-11-01
The development of a new, very small coaxial plasma source based on the microwave plasma torch (MPT) is described. It generates a plasma jet up to 4 mm long and can be operated with a argon gas flow rate less than 70 ml per min at down to 2 W microwave power (2.45 GHz) at atmospheric pressure. It also works well with helium and does not show any wear during a test period of 30 h of operation with argon. It is, in particular, thought to be a source for the atomic spectroscopy of gaseous species. The excitation temperature is found to be ~4700 K for this device operating with helium and 17 W microwave power. A detection limit for an example application in which Cl is detected from HCCl3 is found to be below 66 ppb. For the first time, to our knowledge, microstrip circuits are used to match the small MPT to the generator's 50 OHgr impedance. The design considerations for the microstrip circuits are discussed and an approximated calculation for the layout is presented. With the introduced procedure it is possible to design even smaller MPTs for special applications.
Tapered plasma channels to phase-lock accelerating and focusing forces in laser-plasma accelerators
Rittershofer, W.; Schroeder, C.B.; Esarey, E.; Gruner, F.J.; Leemans, W.P.
2010-05-17
Tapered plasma channels are considered for controlling dephasing of a beam with respect to a plasma wave driven by a weakly-relativistic, short-pulse laser. Tapering allows for enhanced energy gain in a single laser plasma accelerator stage. Expressions are derived for the taper, or longitudinal plasma density variation, required to maintain a beam at a constant phase in the longitudinal and/or transverse fields of the plasma wave. In a plasma channel, the phase velocities of the longitudinal and transverse fields differ, and, hence, the required tapering differs. The length over which the tapered plasma density becomes singular is calculated. Linear plasma tapering as well as discontinuous plasma tapering, which moves beams to adjacent plasma wave buckets, are also considered. The energy gain of an accelerated electron in a tapered laser-plasma accelerator is calculated and the laser pulse length to optimize the energy gain is determined.
NASA Technical Reports Server (NTRS)
Alfven, H.
1981-01-01
Attention is given to experimental and theoretical approaches to plasma physics, plasma phenomena in laboratory and space, field and particle aspects of plasmas, the present state of the classical theory, boundary conditions and circuit dependence, and cosmology. Electric currents in space plasmas are considered, taking into account dualism in physics, particle-related phenomena in plasma physics, magnetic field lines, filaments, local plasma properties and the circuit, electric double layers, field-aligned currents as 'cables', an expanding circuit, different types of plasma regions, the cellular structure of space, and the fine structure of active plasma regions. Other topics discussed are related to circuits, the theory of cosmic plasmas, the origin of the solar system, the coexistence of matter and antimatter, annihilation as a source of energy, the Hubble expansion in a Euclidean space, and a model for the evolution of the Metagalaxy.
Monte Carlo neutral density calculations for ELMO Bumpy Torus
Davis, W.A.; Colchin, R.J.
1986-11-01
The steady-state nature of the ELMO Bumpy Torus (EBT) plasma implies that the neutral density at any point inside the plasma volume will determine the local particle confinement time. This paper describes a Monte Carlo calculation of three-dimensional atomic and molecular neutral density profiles in EBT. The calculation has been done using various models for neutral source points, for launching schemes, for plasma profiles, and for plasma densities and temperatures. Calculated results are compared with experimental observations - principally spectroscopic measurements - both for guidance in normalization and for overall consistency checks. Implications of the predicted neutral profiles for the fast-ion-decay measurement of neutral densities are also addressed.
Modelling the Plasma Jet in Multi-Arc Plasma Spraying
NASA Astrophysics Data System (ADS)
Bobzin, K.; Öte, M.; Schein, J.; Zimmermann, S.; Möhwald, K.; Lummer, C.
2016-08-01
Particle in-flight characteristics in atmospheric plasma spraying process are determined by impulse and heat energy transferred between the plasma jet and injected powder particles. One of the important factors for the quality of the plasma-sprayed coatings is thus the distribution of plasma gas temperatures and velocities in plasma jet. Plasma jets generated by conventional single-arc plasma spraying systems and their interaction with powder particles were subject matter of intensive research. However, this does not apply to plasma jets generated by means of multi-arc plasma spraying systems yet. In this study, a numerical model has been developed which is designated to dealing with the flow characteristics of the plasma jet generated by means of a three-cathode spraying system. The upstream flow conditions, which were calculated using a priori conducted plasma generator simulations, have been coupled to the plasma jet simulations. The significances of the relevant numerical assumptions and aspects of the models are analyzed. The focus is placed on to the turbulence and diffusion/demixing modelling. A critical evaluation of the prediction power of the models is conducted by comparing the numerical results to the experimental results determined by means of emission spectroscopic computed tomography. It is evident that the numerical models exhibit a good accuracy for their intended use.
Multicompartment pharmacokinetic analysis and simulations using a programmable calculator.
Niazi, S
1979-05-01
This paper describes the use of a programmable calculator (HP-97), for fitting plasma concentration profiles to 1 and 2 compartment open models and calculating fitted and derived parameters together with estimates of steady state plasma drug levels following various dosage regimens in clinical settings.
How to Patch Active Plasma and Collisionless Sheath: Pragmatical Guide
NASA Astrophysics Data System (ADS)
Shneider, Mikhail N.; Kaganovich, Igor D.
2002-11-01
Most plasmas have very thin sheath compared with plasma dimension. This necessitates separate calculation of plasma and sheath. Bohm criterion provides boundary condition for calculation of plasma profiles. To calculate sheath properties a value of electric field at the plasma-sheath interface has to be specified in addition to Bohm criterion. The value of the boundary electric field and robust procedure to approximately patch plasma and collisionless sheath with a very good accuracy is reported. Additional information on the subject will be posted in http://www.pppl.gov/pub/report/2002/ http://arxiv.org/abs/physics/ Work supported by the Princeton Plasma Physics Laboratory through a University Research Support Program.
2011-05-01
are documented in the end notes and bibliography. ABSTRACT AUTHOR: COL Thomas J. Rogers TITLE: Support to Special Operations FORMAT...SOF logistics. 13 END NOTES 1 U.S. Army Special Forces, THE GREEN BERETS, Special Forces History and Origins. Special Operations.Com
The special relativistic shock tube
NASA Technical Reports Server (NTRS)
Thompson, Kevin W.
1986-01-01
The shock-tube problem has served as a popular test for numerical hydrodynamics codes. The development of relativistic hydrodynamics codes has created a need for a similar test problem in relativistic hydrodynamics. The analytical solution to the special relativistic shock-tube problem is presented here. The relativistic shock-jump conditions and rarefaction solution which make up the shock tube are derived. The Newtonian limit of the calculations is given throughout.
On-Site was developed to provide modelers and model reviewers with prepackaged tools ("calculators") for performing site assessment calculations. The philosophy behind OnSite is that the convenience of the prepackaged calculators helps provide consistency for simple calculations,...
On-Site was developed to provide modelers and model reviewers with prepackaged tools ("calculators") for performing site assessment calculations. The philosophy behind OnSite is that the convenience of the prepackaged calculators helps provide consistency for simple calculations,...
Cai Hongbo; Zhu Shaoping; Wu Sizhong; Chen Mo; Zhou Cangtao; He, X. T.; Yu Wei; Nagatomo, Hideo
2011-02-15
The efficient magnetic collimation of fast electron flow transporting in overdense plasmas is investigated with two-dimensional collisional particle-in-cell numerical simulations. It is found that the specially engineered targets exhibiting either high-resistivity-core-low-resistivity-cladding structure or low-density-core-high-density-cladding structure can collimate fast electrons. Two main mechanisms to generate collimating magnetic fields are found. In high-resistivity-core-low-resistivity-cladding structure targets, the magnetic field at the interfaces is generated by the gradients of the resistivity and fast electron current, while in low-density-core-high-density-cladding structure targets, the magnetic field is generated by the rapid changing of the flow velocity of the background electrons in transverse direction (perpendicular to the flow velocity) caused by the density jump. The dependences of the maximal magnetic field on the incident laser intensity and plasma density, which are studied by numerical simulations, are supported by our analytical calculations.
NASA Astrophysics Data System (ADS)
Kim, S. H.
2017-05-01
We reason based on the concept of stationary plasma fluctuation that in the free-electron laser (FEL), the Coulomb force from the surrounding electrons and the Ampérian force arising from the beam current do not disrupt the density-deviation mode driven by the laser field in cooperation with the magnetic wiggler. We adopt the synchronization principle that in the state of a stationary plasma density-wave and laser wave, all electrons arriving at the same position can emit laser photons all together only at t = NT + t o , where N is an integer and T is the laser period. We find that in the FEL, the incident laser radiation acts as a dummy field in net stimulated radiation. Using these findings and noticing a previously-recognized concept that the radiation power from an electron is given by Δ E/T, where Δ E is the amplitude of the net work done by the electron during T [1], we derive the laser gain of a self-launched FEL. The thusly derived gain is in excellent agreement with the measured gain.
Observation of H-Mode Operation Windows for ECH Plasmas in Heliotron J
Sano, F.; Mizuuchi, T.; Nagasaki, K.
2004-09-15
The H-mode transition properties of 70-GHz, 0.4-MW electron cyclotron heating (ECH) plasmas in Heliotron J have been studied with special reference to their magnetic configuration dependences, such as the edge iota dependences. Two edge iota windows for the H-mode transition were observed to be (a) 0.54 < {iota}(a)/2{pi} < 0.56 in separatrix discharge plasmas and (b) 0.62 < {iota}>(a)/2{pi} < 0.63 in partial wall-limiter discharge plasmas if a certain threshold line-averaged electron density (n{sub e} = 1.2-1.6 x 10{sup 19} m{sup -3}) is achieved, where {iota}(a) is the vacuum edge iota value and a is the plasma minor radius, respectively. A strong dependence of the quality of the H-mode on the edge topology conditions was revealed. The energy confinement time for the separatrix discharge plasmas was found to be enhanced beyond the normal ISS95 scaling in the transient H-mode phase, being 50% longer than that in the 'before transition' phase. The window characteristics are discussed on the basis of the calculated geometrical poloidal viscous damping rate coefficient in a collisional plasma, indicating that the behavior of the viscous damping rate coefficient alone could not explain the observed characteristics. The bootstrap current properties of ECH plasmas and the relevant electron cyclotron current drive experimental results are also discussed.
NASA Astrophysics Data System (ADS)
Huiskamp, T.; Sengers, W.; Pemen, A. J. M.
2016-12-01
Streamer discharges are efficient non-thermal plasmas for air purification and can be generated in wire-cylinder electrode structures (the plasma reactor). When (sub)nanosecond high-voltage pulses are used to generate the plasma, components like a plasma reactor behave as transmission lines, where transmission times and reflections become important. We want to visually study the influence of these transmission-line effects on the streamer development in the reactor. Therefore, we need a unique experimental setup, which allows us to image the streamers with nanosecond time resolution over the entire length of the plasma reactor. This paper describes the setup we developed for this purpose. The setup consists of a large frame in which a specially designed plasma reactor can be mounted and imaged from below by an intensified charge-coupled device (ICCD) camera. This camera is mounted on a platform which can be moved by a stepper motor. A computer automates all the experiments and controls the camera movement, camera settings, and the nanosecond high-voltage pulse source we use for the experiments. With the automated setup, we can make ICCD images of the entire plasma reactor at different instances of time with nanosecond resolution (with a jitter of less than several hundreds of picoseconds). Consequently, parameters such as the streamer length and width can be calculated automatically.
Advanced plasma diagnostics for plasma processing
NASA Astrophysics Data System (ADS)
Malyshev, Mikhail Victorovich
1999-10-01
A new, non-intrusive, non-perturbing diagnostic method was developed that can be broadly applied to low pressure, weakly ionized plasmas and glow discharges-trace rare gases optical emission spectroscopy (TRG-OES). The method is based on a comparison of intensities of atomic emission from trace amounts of inert gases (He, Ne, Ar, Kr, and Xe) that are added to the discharge to intensities calculated from the theoretical model. The model assumes a Maxwellian electron energy distribution function (EEDF), computes the population of emitting levels both from the ground state and the metastable states of rare gases, and from the best fit between theory and experiment determines electron temperature (Te). Subject to conditions, TRG-OES can also yield electron density or its upper or lower limit. From the comparison of the emission from levels excited predominantly by high energy electrons to that excited by low energy electrons, information about the EEDF can be obtained. The use of TRG-OES also allows a traditionally qualitative actinometry technique (determination of concentration of radical species in plasma through optical emission) to become a precise quantitative method by including Te and rare gases metastables effects. A combination of TRG-OES, advanced actinometry, and Langmuir probe measurements was applied to several different plasma reactors and regimes of operation. Te measurements and experiments to correct excitation cross section were conducted in a laboratory helical resonator. Two chamber configuration of a commercial (Lam Research) metal etcher were studied to determine the effects of plasma parameters on plasma-induced damage. Two different methods (RF inductive coupling and ultra-high frequency coupling) for generating a plasma in a prototype reactor were also studied. Pulsed plasmas, a potential candidate to eliminate the plasma-induced damage to microelectronics devices that occurs in manufacturing due to differential charging of the wafer, have
SPECIAL CLASSES FOR STUDENTS WITH SPECIAL NEEDS.
ERIC Educational Resources Information Center
DOWELL, G.L.
A SPECIAL 3-YEAR TRAINING PROGRAM IN FARM POWER AND MACHINERY WAS DEVELOPED TO PROVIDE FOR DIFFERENT LEVELS OF STUDENT ACHIEVEMENT AND TO HELP MEET THE NEED FOR SKILLED WORKERS IN THE MISSISSIPPI DELTA AREA. CHANGES IN THE LEARNING ENVIRONMENT OF STUDENTS TRANSFERRED FROM REGULAR VOCATIONAL AGRICULTURE CLASSES TO THE SPECIAL CLASSES PROVIDE A MORE…
Mississippi Special Olympics: Special Events Manual.
ERIC Educational Resources Information Center
Heinze, Toni; Cooper, Walter E.
Provided in the manual are organizational guidelines and suggested activities for a Special Evants segment of the Mississippi Special Olympics Program to encourage participation by low motor functioning, multihandicapped, mentally retarded persons. Information is provided concerning objectives, organizational set-up, guidelines, communication…
The EOSTA model for opacities and EOS calculations
NASA Astrophysics Data System (ADS)
Barshalom, Avraham; Oreg, Joseph
2007-11-01
The EOSTA model developed recently combines the STA and INFERNO models to calculate opacities and EOS on the same footing. The quantum treatment of the plasma continuum and the inclusion of the resulted shape resonances yield a smooth behavior of the EOS and opacity global quantities vs density and temperature. We will describe the combined model and focus on its latest improvements. In particular we have extended the use of the special representation of the relativistic virial theorem to obtain an exact differential equation for the free energy. This equation, combined with a boundary condition at the zero pressure point, serves to advance the LDA EOS results significantly. The method focuses on applicability to high temperature and high density plasmas, warm dens matter etc. but applies at low temperatures as well treating fluids and even solids. Excellent agreement is obtained with experiments covering a wide range of density and temperature. The code is now used to create EOS and opacity databases for the use of hydro-dynamical simulations.
Applications of the concept of generalized vorticity to space plasmas
NASA Technical Reports Server (NTRS)
Banks, P. M.; Edwards, W. F.; Rasmussen, C.; Thompson, R. C.
1981-01-01
A reformulation of the momentum equation for electrons or ions in a collisionless plasma leads to an equation which describes the behavior of the plasma in terms of a generalized vorticity. This vorticity is both divergence-free and conserved along plasma flow streamlines. When the plasma has zero vorticity, a special relation is established which appears to have application to small scale magnetic features within both conventional space plasmas and superconductors.
Jones, M.E.; Winske, D.; Keinigs, R.; Lemons, D.
1996-05-01
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project has been to develop a fundamental understanding of dusty plasmas at the Laboratory. While dusty plasmas are found in space in galactic clouds, planetary rings, and cometary tails, and as contaminants in plasma enhanced fabrication of microelectronics, many of their properties are only partially understood. Our work has involved both theoretical analysis and self-consistent plasma simulations to understand basic properties of dusty plasmas related to equilibrium, stability, and transport. Such an understanding can improve the control and elimination of plasma dust in industrial applications and may be important in the study of planetary rings and comet dust tails. We have applied our techniques to the study of charging, dynamics, and coagulation of contaminants in plasma processing reactors for industrial etching and deposition processes and to instabilities in planetary rings and other space plasma environments. The work performed in this project has application to plasma kinetics, transport, and other classical elementary processes in plasmas as well as to plasma waves, oscillations, and instabilities.
PREFACE: Special issue: CAMOP-MOLEC XVII Special issue: CAMOP-MOLEC XVII
NASA Astrophysics Data System (ADS)
Vasyutinskii, Oleg
2009-10-01
This special issue of CAMOP/Physica Scripta presents highlights from the scientific contributions presented at the European Conference on Dynamics of Molecular Systems (MOLEC XVII) held on 23-29 August 2008 at St Petersburg, Russia. This meeting was the seventeenth in a series of biannual meetings that started in 1976, when the first conference was held in Trento, Italy. Subsequent meetings were held at Brandbjerg Hojskole (Denmark), Oxford (UK), Nijmegen (The Netherlands), Jerusalem (Israel), Aussois (France), Assisi (Italy), Bernkastel-Kues (Germany), Prague (Czech Republic), Salamanca (Spain), Nyborg Strand (Denmark), Bristol (UK), Jerusalem (Israel), Istanbul (Turkey), Nunspeet (The Netherlands) and Trento (Italy). In 2008, the meeting was jointly organized by scientists from the Ioffe Institute, Russian Academy of Sciences, St Petersburg, Herzen State University, St Petersburg, Moscow State University, St Petersburg Polytechnical University, and St Petersburg State University. About 150 scientists from 21 countries visited Pushkin, a beautiful suburb of St Petersburg near the famous palace of Empress Catherine II, and discussed the state of the art and trends in the field, as well as new methods and applications, during 24 plenary lectures, 36 hot topic talks and two evening poster sessions. A special event was the presentation of the MOLEC XVII award to Professor Grabriel Balint-Kurti for his outstanding contributions to the theory of reaction dynamics and molecular photodissociation. Further information is available from the homepage of the meeting: http://www.ioffe.ru/MOLEC17/. This special issue covers different aspects of atomic and molecular interactions, with emphasis on both experimental and theoretical studies of the dynamics of elastic, inelastic and reactive encounters between atoms, molecules, ions, clusters and surfaces. More specifically, it includes molecular collisions in different environments; plasma, atmospheric, interstellar and combustion
Lysakowski, A; Figueras, H; Price, S D; Peng, Y Y
1999-01-18
To determine whether there are anatomical correlates for intraterminal Ca2+ stores to regulate exocytosis of dense-cored vesicles (DCVs) and whether these stores can modulate exocytosis of synaptic vesicles, we studied the spatial distributions of DCVs, smooth endoplasmic reticulum (SER), and mitochondria in 19 serially reconstructed nerve terminals in bullfrog sympathetic ganglia. On average, each bouton had three active zones, 214 DCVs, 26 SER fragments (SERFs), and eight mitochondria. DCVs, SERFs and mitochondria were located, on average, 690, 624, and 526 nm, respectively, away from active zones. Virtually no DCVs were within "docking" (i.e., < or = 50 nm) distances of the active zones. Thus, it is unlikely that DCV exocytosis occurs at active zones via mechanisms similar to those for exocytosis of synaptic vesicles. Because there were virtually no SERFs or mitochondria within 50 nm of any active zone, Ca2+ modulation by these organelles is unlikely to affect ACh release evoked by a single action potential. In contrast, 30% of DCVs and 40% of SERFs were located within 50 nm of the nonspecialized regions of the plasma membrane. Because each bouton had at least one SERF within 50 nm of the plasma membrane and most of these SERFs had DCVs, but not mitochondria, near them, it is possible for Ca2+ release from the SER to provide the Ca2+ necessary for DCV exocytosis. The fact that 60% of the mitochondria had some part within 50 nm of the plasma membrane means that it is possible for mitochondrial Ca2+ buffering to affect DCV exocytosis.
Turbulent complex (dusty) plasma
NASA Astrophysics Data System (ADS)
Zhdanov, Sergey; Schwabe, Mierk
2017-04-01
As a paradigm of complex system dynamics, solid particles immersed into a weakly ionized plasma, so called complex (dusty) plasmas, were (and continue to be) a subject of many detailed studies. Special types of dynamical activity have been registered, in particular, spontaneous pairing, entanglement and cooperative action of a great number of particles resulting in formation of vortices, self-propelling, tunneling, and turbulent movements. In the size domain of 1-10 mkm normally used in experiments with complex plasmas, the characteristic dynamic time-scale is of the order of 0.01-0.1 s, and these particles can be visualized individually in real time, providing an atomistic (kinetic) level of investigations. The low-R turbulent flow induced either by the instability in a complex plasma cloud or formed behind a projectile passing through the cloud is a typical scenario. Our simulations showed formation of a fully developed system of vortices and demonstrated that the velocity structure functions scale very close to the theoretical predictions. As an important element of self-organization, cooperative and turbulent particle motions are present in many physical, astrophysical, and biological systems. Therefore, experiments with turbulent wakes and turbulent complex plasma oscillations are a promising mean to observe and study in detail the anomalous transport on the level of individual particles.
Theory and observation of a dynamically evolving negative ion plasma. [in F region
NASA Technical Reports Server (NTRS)
Mendillo, M.; Forbes, J.
1982-01-01
The study described here examines the full range of negative-ion chemistry in the upper ionosphere by using current reaction rate data to investigate the many chemical paths SF6-type injections might take in an F region environment. Special attention is given to the conditions required to create heavy negative ions that persist long enough to affect the dynamical properties of the F region. The ambipolar diffusion characteristics of a three-component plasma are described, and estimates are given of the incoherent scatter spectra obtained from such a plasma. Model calculations using a first-order chemical code are defined and tested in order to investigate the actual types of negative-ion plasma capable of being created under nighttime conditions.
Plasma Sources for Medical Applications - A Comparison of Spot Like Plasmas and Large Area Plasmas
NASA Astrophysics Data System (ADS)
Weltmann, Klaus-Dieter
2015-09-01
Plasma applications in life science are currently emerging worldwide. Whereas today's commercially available plasma surgical technologies such as argon plasma coagulation (APC) or ablation are mainly based on lethal plasma effects on living systems, the newly emerging therapeutic applications will be based on selective, at least partially non-lethal, possibly stimulating plasma effects on living cells and tissue. Promising results could be obtained by different research groups worldwide revealing a huge potential for the application of low temperature atmospheric pressure plasma in fields such as tissue engineering, healing of chronic wounds, treatment of skin diseases, tumor treatment based on specific induction of apoptotic processes, inhibition of biofilm formation and direct action on biofilms or treatment of dental diseases. The development of suitable and reliable plasma sources for the different therapies requires an in-depth knowledge of their physics, chemistry and parameters. Therefore much basic research still needs to be conducted to minimize risk and to provide a scientific fundament for new plasma-based medical therapies. It is essential to perform a comprehensive assessment of physical and biological experiments to clarify minimum standards for plasma sources for applications in life science and for comparison of different sources. One result is the DIN-SPEC 91315, which is now open for further improvements. This contribution intends to give an overview on the status of commercial cold plasma sources as well as cold plasma sources still under development for medical use. It will discuss needs, prospects and approaches for the characterization of plasmas from different points of view. Regarding the manageability in everyday medical life, atmospheric pressure plasma jets (APPJ) and dielectric barrier discharges (DBD) are of special interest. A comprehensive risk-benefit assessment including the state of the art of commercial sources for medical use
Coating of plasma polymerized film
NASA Technical Reports Server (NTRS)
Morita, S.; Ishibashi, S.
1980-01-01
Plasma polymerized thin film coating and the use of other coatings is suggested for passivation film, thin film used for conducting light, and solid body lubrication film of dielectrics of ultra insulators for electrical conduction, electron accessories, etc. The special features of flow discharge development and the polymerized film growth mechanism are discussed.
Electromagnetic strong plasma turbulence
Melatos, A.; Jenet, F. A.; Robinson, P. A.
2007-02-15
The first large-scale simulations of continuously driven, two-dimensional electromagnetic strong plasma turbulence are performed, for electron thermal speeds 0.01c{<=}v{<=}0.57c, by integrating the Zakharov equations for coupled Langmuir and transverse (T) waves near the plasma frequency. Turbulence scalings and wave number spectra are calculated, a transition is found from a mix of trapped and free T eigenstates for v{>=}0.1c to just free eigenstates for v{<=}0.1c, and wave energy densities are observed to undergo slow quasiperiodic oscillations.
Special Education in Yugoslavia.
ERIC Educational Resources Information Center
Hrnjica, Sulejman
1990-01-01
This article describes Yugoslavia's education system, health and welfare services for children with disabilities, the nature and organization of special education services, the integration of disabled children in ordinary schools, models for training special educators, and problems. (DB)
Mathematical modeling of quartz particle melting process in plasma-chemical reactor
Volokitin, Oleg Volokitin, Gennady Skripnikova, Nelli Shekhovtsov, Valentin; Vlasov, Viktor
2016-01-15
Among silica-based materials vitreous silica has a special place. The paper presents the melting process of a quartz particle under conditions of low-temperature plasma. A mathematical model is designed for stages of melting in the experimental plasma-chemical reactor. As calculation data show, quartz particles having the radius of 0.21≤ r{sub p} ≤0.64 mm completely melt at W = 0.65 l/s particle feed rate depending on the Nusselt number, while 0.14≤ r{sub p} ≤0.44 mm particles melt at W = 1.4 l/s. Calculation data showed that 2 mm and 0.4 mm quartz particles completely melted during and 0.1 s respectively. Thus, phase transformations occurred in silicon dioxide play the important part in its heating up to the melting temperature.
Highly charged ions in magnetic fusion plasmas: research opportunities and diagnostic necessities
NASA Astrophysics Data System (ADS)
Beiersdorfer, P.
2015-07-01
Highly charged ions play a crucial role in magnetic fusion plasmas. These plasmas are excellent sources for producing highly charged ions and copious amounts of radiation for studying their atomic properties. These studies include calibration of density diagnostics, x-ray production by charge exchange, line identifications and accurate wavelength measurements, and benchmark data for ionization balance calculations. Studies of magnetic fusion plasmas also consume a large amount of atomic data, especially in order to develop new spectral diagnostics. Examples we give are the need for highly accurate wavelengths as references for measurements of bulk plasma motion, the need for accurate line excitation rates that encompass both electron-impact excitation and indirect line formation processes, for accurate position and resonance strength information of dielectronic recombination satellite lines that may broaden or shift diagnostic lines or that may provide electron temperature information, and the need for accurate ionization balance calculations. We show that the highly charged ions of several elements are of special current interest to magnetic fusion, notably highly charged ions of argon, iron, krypton, xenon, and foremost of tungsten. The electron temperatures thought to be achievable in the near future may produce W70+ ions and possibly ions with even higher charge states. This means that all but a few of the most highly charged ions are of potential interest as plasma diagnostics or are available for basic research.
Specialization of Perceptual Processes.
1994-09-01
engineering that cannot be transferred to other prob- lems. My second thesis is that specialized systems can be analyzed and understood in a principled...manner, one that allows general lessons to be extracted from specialized systems. I will present a general approach to analyzing specialization...Lightweight vision : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 137 12.3 Studying the world
ERIC Educational Resources Information Center
Whitfield, Keith E.; Edwards, Christopher L.
2011-01-01
Mentorship is critical for career development. Members of special populations are at increased risk of information shortfalls and advice that is not framed with cultural sensitivity. Special knowledge and skills are needed to successfully mentor members of ethnic minority and other special populations. Midlevel and senior scientists need…
Special Effects Activity Guide.
ERIC Educational Resources Information Center
Boxer, Jennifer; Valenta, Carol
This guide accompanies "Special Effects," a 40-minute IMAX film and "Special Effects II", a multimedia, interactive traveling exhibit designed by the California Museum of Science and Industry. The exhibit focuses on the underlying scientific and technical processes of special effects from the earliest motion picture to state-of-the-art digital…
Assessing Special Educational Needs.
ERIC Educational Resources Information Center
Wolfendale, Sheila, Ed.
This essays in this book contain valuable and up-to-date information about current issues and developments in assessing special educational needs. The context of the book is the mainstream setting in the United Kingdom. The aim of these chapters is to consider special needs in inclusive education, consistent with British special needs legislation.…
ERIC Educational Resources Information Center
Whitfield, Keith E.; Edwards, Christopher L.
2011-01-01
Mentorship is critical for career development. Members of special populations are at increased risk of information shortfalls and advice that is not framed with cultural sensitivity. Special knowledge and skills are needed to successfully mentor members of ethnic minority and other special populations. Midlevel and senior scientists need…
Radiation characteristics of femtosecond laser-induced plasma channel Vee antenna
NASA Astrophysics Data System (ADS)
Choe, Yun-Sik; Hao, Zuoqiang; Lin, Jingquan
2015-06-01
A virtual reconfigurable plasma Vee antenna consisting of a set of laser plasma filaments produced by femtosecond laser pulses in air is investigated in this paper. The calculation results show that radiation pattern becomes more complex and gain shows initially rapid rise but gradually saturate as the leg length increases, but the pattern and gain are not seriously affected by the plasma conductivity; particularly, the gain of the Vee antenna with plasma conductivity σ = 100S/m can reach about 80% of that of a copper antenna. Radiation efficiency of the antenna has shown a strong dependence on radius of the antenna leg, and an efficiency of 65%, considered to have a proper performance, can be obtained with the channel radius of about 10 mm. Apex angle variation can lead to significant change of the radiation pattern and influence the gain; the best apex angle corresponding to maximal gain and good directivity for the third resonance antenna leg length is found to be at 74° at 600 MHz and σ = 100 S/m. The calculation has shown that at terawatt laser power level, the plasma channel conductivity is close to that of conventional plasma antenna, and peak gain of the Vee antenna is more than 8 dB with a good directivity. In addition, the radiation pattern of special Vee antennas with apex angle 180°-dipole antennas, for first and third resonance leg lengths, is compared and underneath physics of the difference is given. The laser-induced plasma channel antenna is especially suitable for achieving good directivity and gain, which has advantage over conventional plasma antenna with gas discharge tube or metal antenna.
Radiation characteristics of femtosecond laser-induced plasma channel Vee antenna
Choe, Yun-Sik; Hao, Zuoqiang; Lin, Jingquan
2015-06-15
A virtual reconfigurable plasma Vee antenna consisting of a set of laser plasma filaments produced by femtosecond laser pulses in air is investigated in this paper. The calculation results show that radiation pattern becomes more complex and gain shows initially rapid rise but gradually saturate as the leg length increases, but the pattern and gain are not seriously affected by the plasma conductivity; particularly, the gain of the Vee antenna with plasma conductivity σ = 100S/m can reach about 80% of that of a copper antenna. Radiation efficiency of the antenna has shown a strong dependence on radius of the antenna leg, and an efficiency of 65%, considered to have a proper performance, can be obtained with the channel radius of about 10 mm. Apex angle variation can lead to significant change of the radiation pattern and influence the gain; the best apex angle corresponding to maximal gain and good directivity for the third resonance antenna leg length is found to be at 74° at 600 MHz and σ = 100 S/m. The calculation has shown that at terawatt laser power level, the plasma channel conductivity is close to that of conventional plasma antenna, and peak gain of the Vee antenna is more than 8 dB with a good directivity. In addition, the radiation pattern of special Vee antennas with apex angle 180°-dipole antennas, for first and third resonance leg lengths, is compared and underneath physics of the difference is given. The laser-induced plasma channel antenna is especially suitable for achieving good directivity and gain, which has advantage over conventional plasma antenna with gas discharge tube or metal antenna.
Distorted Wave Calculations and Applications
NASA Technical Reports Server (NTRS)
Bhatia, A. K.; Fisher, Richard R. (Technical Monitor)
2000-01-01
Physical properties such as temperature and electron density of solar plasma and other astrophysical objects can be inferred from EUV and X-ray emission lines observed from space. These lines are emitted when the higher states of an ion are excited by electron impact and then decay by photon emission. Excitation cross sections are required for the spectroscopic analyses of the observations and various approximations have been used to calculate the scattering functions. One of them which has been widely used is a distorted wave approximation. This approximation, along with its applications to solar observations, is discussed. The Bowen fluorescence mechanism and optical depth effects are also discussed. It is concluded that such calculations are reliable for highly charged ions and for high electron temperatures.
Distorted Wave Calculation and Applications
NASA Technical Reports Server (NTRS)
Bhatia, A. K.
2000-01-01
Physical properties such as temperature and electron density of solar plasma and other astrophysical objects can be inferred from EUV and X-ray emission lines observed from space. These lines are emitted when the higher states of an ion are excited by electron impact and then decay by photon emission. Excitation cross sections are required for the spectroscopic analyses of the observations and various approximations have been used to calculate the scattering functions. One of them which has been widely used is a distorted wave approximation. This approximation, along with its applications to solar observations, is discussed. The Bowen fluorescence mechanism and optical depth effects are also discussed. It is concluded that such calculations are reliable for highly charged ions and for high electron temperatures.
Distillation Calculations with a Programmable Calculator.
ERIC Educational Resources Information Center
Walker, Charles A.; Halpern, Bret L.
1983-01-01
Describes a three-step approach for teaching multicomponent distillation to undergraduates, emphasizing patterns of distribution as an aid to understanding the separation processes. Indicates that the second step can be carried out by programmable calculators. (A more complete set of programs for additional calculations is available from the…
Distillation Calculations with a Programmable Calculator.
ERIC Educational Resources Information Center
Walker, Charles A.; Halpern, Bret L.
1983-01-01
Describes a three-step approach for teaching multicomponent distillation to undergraduates, emphasizing patterns of distribution as an aid to understanding the separation processes. Indicates that the second step can be carried out by programmable calculators. (A more complete set of programs for additional calculations is available from the…
The rating reliability calculator
Solomon, David J
2004-01-01
Background Rating scales form an important means of gathering evaluation data. Since important decisions are often based on these evaluations, determining the reliability of rating data can be critical. Most commonly used methods of estimating reliability require a complete set of ratings i.e. every subject being rated must be rated by each judge. Over fifty years ago Ebel described an algorithm for estimating the reliability of ratings based on incomplete data. While his article has been widely cited over the years, software based on the algorithm is not readily available. This paper describes an easy-to-use Web-based utility for estimating the reliability of ratings based on incomplete data using Ebel's algorithm. Methods The program is available public use on our server and the source code is freely available under GNU General Public License. The utility is written in PHP, a common open source imbedded scripting language. The rating data can be entered in a convenient format on the user's personal computer that the program will upload to the server for calculating the reliability and other statistics describing the ratings. Results When the program is run it displays the reliability, number of subject rated, harmonic mean number of judges rating each subject, the mean and standard deviation of the averaged ratings per subject. The program also displays the mean, standard deviation and number of ratings for each subject rated. Additionally the program will estimate the reliability of an average of a number of ratings for each subject via the Spearman-Brown prophecy formula. Conclusion This simple web-based program provides a convenient means of estimating the reliability of rating data without the need to conduct special studies in order to provide complete rating data. I would welcome other researchers revising and enhancing the program. PMID:15117416
Propagation Of Dense Plasma Jets
NASA Astrophysics Data System (ADS)
Turchi, Peter J.; Davis, John F.
1988-05-01
A variety of schemes have been proposed over the last two decades for delivering lethal amounts of energy and/or momentum to targets such as missiles and high speed aircraft. Techniques have ranged from high energy lasers and high voltage charged-particle accelerators to less exotic but still challenging devices such as electromagnetic railguns. One class of technology involves the use of high speed plasmas. The primary attraction of such technology is the possibility of utilizing relatively compact accelerators and electrical power systems that could allow highly mobile and agile operation from rocket or aircraft platforms, or in special ordnance. Three years ago, R & D Associates examined the possibility of plasma propagation for military applications and concluded that the only viable approach consisted of long dense plasma jets, contained in radial equilibrium by the atmosphere, while propagating at speeds of about 10 km/s. Without atmospheric confinement the plasma density would diminish too rapidly for adequate range and lethality. Propagation of atmospherically-confined jets at speeds much greater than 10 km/s required significant increases in power levels and/or operating altitudes to achieve useful ranges. The present research effort has been developing the experimental conditions necessary to achieve reasonable comparison with theoretical predictions for plasma jet propagation in the atmosphere. Time-resolved measurements have been made of high speed argon plasma jets penetrating a helium background (simulating xenon jets propagating into air). Basic radial confinement of the jet has been observed by photography and spectroscopy and structures in the flow field resemble those predicted by numerical calculations. Results from our successful initial experiments have been used to design improved diagnostic procedures and arcjet source characteristics for further experiments. In experiments with a modified arcjet source, radial confinement of the jet is again
Developments in special geometry
NASA Astrophysics Data System (ADS)
Mohaupt, Thomas; Vaughan, Owen
2012-02-01
We review the special geometry of Script N = 2 supersymmetric vector and hypermultiplets with emphasis on recent developments and applications. A new formulation of the local c-map based on the Hesse potential and special real coordinates is presented. Other recent developments include the Euclidean version of special geometry, and generalizations of special geometry to non-supersymmetric theories. As applications we disucss the proof that the local r-map and c-map preserve geodesic completeness, and the construction of four- and five-dimensional static solutions through dimensional reduction over time. The shared features of the real, complex and quaternionic version of special geometry are stressed throughout.
MHD control in burning plasmas MHD control in burning plasmas
NASA Astrophysics Data System (ADS)
Donné, Tony; Liang, Yunfeng
2012-07-01
in the field of burn control is to find the proper balance between desired and detrimental effects of the various MHD modes and to develop the methods and tools for active feedback control of MHD modes in burning plasmas. Therefore, it is necessary to understand the dynamics of the system, in this case the mutual interactions between the fast alpha particles and the MHD instabilities. Since burning plasmas do not yet exist, the relevant experimental work until ITER comes into full operation needs to be largely based on alpha-particle simulation experiments in which the alpha particles are accelerated to high energies by means of special heating techniques. The precise conditions of a burning plasma can be only partly mimicked in present tokamaks. Hence, also a detailed computational modelling effort is needed, in order to understand the impact of findings in present machines for those of the future. In 2011 two dedicated workshops were devoted to MHD control. Firstly, there was a workshop on Control of Burning Plasmas that took place from 21-25 March 2011 at the Lorentz Centre in Leiden, The Netherlands. Secondly, the 480th Wilhelm and Else Heraeus Seminar that took place from 16-18 June in Bad Honnef, Germany was devoted to Active Control of Instabilities in Hot Plasmas. This special issue presents a collection of papers that have been presented at the two workshops, along with a few papers that are the result of an open call to contribute to this special issue.
General very special relativity in Finsler cosmology
Kouretsis, A. P.; Stathakopoulos, M.; Stavrinos, P. C.
2009-05-15
General very special relativity (GVSR) is the curved space-time of very special relativity (VSR) proposed by Cohen and Glashow. The geometry of general very special relativity possesses a line element of Finsler geometry introduced by Bogoslovsky. We calculate the Einstein field equations and derive a modified Friedmann-Robertson-Walker cosmology for an osculating Riemannian space. The Friedmann equation of motion leads to an explanation of the cosmological acceleration in terms of an alternative non-Lorentz invariant theory. A first order approach for a primordial-spurionic vector field introduced into the metric gives back an estimation of the energy evolution and inflation.
General very special relativity in Finsler cosmology
NASA Astrophysics Data System (ADS)
Kouretsis, A. P.; Stathakopoulos, M.; Stavrinos, P. C.
2009-05-01
General very special relativity (GVSR) is the curved space-time of very special relativity (VSR) proposed by Cohen and Glashow. The geometry of general very special relativity possesses a line element of Finsler geometry introduced by Bogoslovsky. We calculate the Einstein field equations and derive a modified Friedmann-Robertson-Walker cosmology for an osculating Riemannian space. The Friedmann equation of motion leads to an explanation of the cosmological acceleration in terms of an alternative non-Lorentz invariant theory. A first order approach for a primordial-spurionic vector field introduced into the metric gives back an estimation of the energy evolution and inflation.
Calculator program speeds rod pump design
Engineer, R.; Davis, C.L.
1984-02-01
Matching sucker rod pump characteristics to a specific application is greatly simplified with this program, intended for use with an HP-41CV hand-held computer. The user inputs application data and the program calculates all necessary design criteria, including Mill's acceleration factor, peak and minimum polish rod loads and horsepower required. Sample calculations are provided, together with a thorough discussion of special design considerations involved in huff-and-puff applications.
Determination of plasma density from data on the ion current to cylindrical and planar probes
Voloshin, D. G. Vasil’eva, A. N.; Kovalev, A. S.; Mankelevich, Yu. A.; Rakhimova, T. V.
2016-12-15
To improve probe methods of plasma diagnostics, special probe measurements were performed and numerical models describing ion transport to a probe with allowance for collisions were developed. The current–voltage characteristics of cylindrical and planar probes were measured in an RF capacitive discharge in argon at a frequency of 81 MHz and plasma densities of 10{sup 10}–10{sup 11} cm{sup –3}, typical of modern RF reactors. 1D and 2D numerical models based on the particle-in-cell method with Monte Carlo collisions for simulating ion motion and the Boltzmann equilibrium for electrons are developed to describe current collection by a probe. The models were used to find the plasma density from the ion part of the current–voltage characteristic, study the effect of ion collisions, and verify simplified approaches to determining the plasma density. A 1D hydrodynamic model of the ion current to a cylindrical probe with allowance for ion collisions is proposed. For a planar probe, a method to determine the plasma density from the averaged numerical results is developed. A comparative analysis of different approaches to calculating the plasma density from the ion current to a probe is performed.
ITER Port Interspace Pressure Calculations
Carbajo, Juan J; Van Hove, Walter A
2016-01-01
The ITER Vacuum Vessel (VV) is equipped with 54 access ports. Each of these ports has an opening in the bioshield that communicates with a dedicated port cell. During Tokamak operation, the bioshield opening must be closed with a concrete plug to shield the radiation coming from the plasma. This port plug separates the port cell into a Port Interspace (between VV closure lid and Port Plug) on the inner side and the Port Cell on the outer side. This paper presents calculations of pressures and temperatures in the ITER (Ref. 1) Port Interspace after a double-ended guillotine break (DEGB) of a pipe of the Tokamak Cooling Water System (TCWS) with high temperature water. It is assumed that this DEGB occurs during the worst possible conditions, which are during water baking operation, with water at a temperature of 523 K (250 C) and at a pressure of 4.4 MPa. These conditions are more severe than during normal Tokamak operation, with the water at 398 K (125 C) and 2 MPa. Two computer codes are employed in these calculations: RELAP5-3D Version 4.2.1 (Ref. 2) to calculate the blowdown releases from the pipe break, and MELCOR, Version 1.8.6 (Ref. 3) to calculate the pressures and temperatures in the Port Interspace. A sensitivity study has been performed to optimize some flow areas.
Wang, Zhehui; Barnes, Cris W.
2002-01-01
There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.
Geometric Gyrokinetic Theory for Edge Plasma
Qin, H; Cohen, R H; Nevins, W M; Xu, X Q
2007-01-18
It turns out that gyrokinetic theory can be geometrically formulated as special cases of a geometrically generalized Vlasov-Maxwell system. It is proposed that the phase space of the spacetime is a 7-dimensional fiber bundle P over the 4-dimensional spacetime M, and that a Poincare-Cartan-Einstein 1-form {gamma} on the 7-dimensional phase space determines particles worldlines in the phase space. Through Liouville 6-form {Omega} and fiber integral, the 1-form {gamma} also uniquely defines a geometrically generalized Vlasov-Maxwell system as a field theory for the collective electromagnetic field. The geometric gyrokinetic theory is then developed as a special case of the geometrically generalized Vlasov-Maxwell system. In its most general form, gyrokinetic theory is about a symmetry, called gyro-symmetry, for magnetized plasmas, and the 1-form {gamma} again uniquely defines the gyro-symmetry. The objective is to decouple the gyro-phase dynamics from the rest of particle dynamics by finding the gyro-symmetry in {gamma}. Compared with other methods of deriving the gyrokinetic equations, the advantage of the geometric approach is that it allows any approximation based on mathematical simplification or physical intuition to be made at the 1-form level, and yet the field theories still have the desirable exact conservation properties such as phase space volume conservation and energy-momentum conservation if the 1-form does not depend on the spacetime coordinate explicitly. A set of generalized gyrokinetic equations valid for the edge plasmas is then derived using this geometric method. This formalism allows large-amplitude, time-dependent background electromagnetic fields to be developed fully nonlinearly in addition to small-amplitude, short-wavelength electromagnetic perturbations. The fact that we adopted the geometric method in the present study does not necessarily imply that the major results reported here can not be achieved using classical methods. What the
Baker, W.R.
1961-08-22
A device is described for establishing and maintaining a high-energy, rotational plasma for use as a fast discharge capacitor. A disc-shaped, current- conducting plasma is formed in an axinl magnetic field and a crossed electric field, thereby creating rotational kinetic enengy in the plasma. Such energy stored in the rotation of the plasma disc is substantial and is convertible tc electrical energy by generator action in an output line electrically coupled to the plasma volume. Means are then provided for discharging the electrical energy into an external circuit coupled to the output line to produce a very large pulse having an extremely rapid rise time in the waveform thereof. (AE C)
Furth, H.P.; Chambers, E.S.
1962-03-01
BS>A method is given for ion cyclotron resonance heatthg of a magnetically confined plasma by an applied radio-frequency field. In accordance with the invention, the radiofrequency energy is transferred to the plasma without the usual attendent self-shielding effect of plasma polarlzatlon, whereby the energy transfer is accomplished with superior efficiency. More explicitly, the invention includes means for applying a radio-frequency electric field radially to an end of a plasma column confined in a magnetic mirror field configuration. The radio-frequency field propagates hydromagnetic waves axially through the column with the waves diminishing in an intermediate region of the column at ion cyclotron resonance with the fleld frequency. In such region the wave energy is converted by viscous damping to rotational energy of the plasma ions. (AEC)
NASA Astrophysics Data System (ADS)
Smarandache, Florentin
2015-11-01
``Unmatter Plasma'' is a novel form of plasma, exclusively made of matter and its antimatter counterpart. An experiment (2015) on matter-antimatter plasma [or unmatter plasma] was recently successful at the Astra Gemini laser facility at the Rutherford Appleton Laboratory, Oxford, United Kingdom. The experiment that was made has produced electron-positron plasma. The positron is the antimatter of the electron, having an opposite charge of the electron, but the other properties are the same. Unmatter is considered as a combination of matter and antimatter. For example electron-positron is a type of unmatter. We coined the word ``unmatter'' (2004) that means neither matter nor antimatter, but something in between. Besides matter and antimatter there may exist unmatter (as a new form of matter) in accordance with the neutrosophy theory that between an entity and its opposite there exist intermediate entities.
Filamentary magnetohydrodynamic plasmas
Kinney, R.; Tajima, T.; Petviashvili, N.; McWilliams, J.C.
1993-05-01
A filamentary construct of magnetohydrodynamical plasma dynamics, based on the Elsasser variables was developed. This approach is modeled after discrete vortex models of hydrodynamical turbulence, which cannot be expected in general to produce results identical to ones based on a Fourier decomposition of the fields. In a highly intermittent plasma, the induction force is small compared to the convective motion, and when this force is neglected. the plasma vortex system is described by a Hamiltonian. For a system with many such vortices we present a statistical treatment of a collection of discrete current-vorticity concentrations. Canonical and microcanonical statistical calculations show that both the vorticity and the current spectra are peaked at long wavelengths, and the expected states revert to known hydrodynamical states as the magnetic field vanishes. These results differ from previous Fourier-based statistical theories. but it is found that when the filament calculation is expanded to include the inductive force, the results approach the Fourier equilibria in the low-temperature limit, and the previous Hamiltonian plasma vortex results in the high-temperature limit. Numerical simulations of a large number of filaments are carried out and support the theory. A three-dimensional vortex model is outlined as well, which is also Hamiltonian when the inductive force is neglected.
46 CFR 172.165 - Intact stability calculations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 46 Shipping 7 2011-10-01 2011-10-01 false Intact stability calculations. 172.165 Section 172.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.165 Intact stability calculations. (a) Design calculations must...
46 CFR 172.165 - Intact stability calculations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 46 Shipping 7 2012-10-01 2012-10-01 false Intact stability calculations. 172.165 Section 172.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.165 Intact stability calculations. (a) Design calculations must...
46 CFR 172.165 - Intact stability calculations.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 46 Shipping 7 2013-10-01 2013-10-01 false Intact stability calculations. 172.165 Section 172.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.165 Intact stability calculations. (a) Design calculations must...
46 CFR 172.165 - Intact stability calculations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 46 Shipping 7 2010-10-01 2010-10-01 false Intact stability calculations. 172.165 Section 172.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.165 Intact stability calculations. (a) Design calculations must...
46 CFR 172.165 - Intact stability calculations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 7 2014-10-01 2014-10-01 false Intact stability calculations. 172.165 Section 172.165 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.165 Intact stability calculations. (a) Design calculations must...
Castejon, F.; Pavlov, S. S.
2006-07-15
The fully relativistic plasma dielectric tensor for any wave and plasma parameter is estimated on the basis of the exact plasma dispersion functions concept. The inclusion of this concept allows one to write the tensor in a closed and compact form and to reduce the tensor evaluation to the calculation of those functions. The main analytical properties of these functions are studied and two methods are given for their evaluation. The comparison between the exact dielectric tensor with the weakly relativistic approximation, widely used presently in plasma waves calculations, is given as well as the range of plasma temperature, harmonic number, and propagation angle in which the weakly relativistic approximation is valid.
7 CFR 760.506 - Payment calculations.
Code of Federal Regulations, 2014 CFR
2014-01-01
... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Tree Assistance Program § 760.506 Payment calculations. (a) Payment to an eligible orchardist or nursery tree grower for the cost of replanting or rehabilitating trees, bushes, or vines damaged or lost due to a natural disaster, in excess of 15 percent...
7 CFR 760.506 - Payment calculations.
Code of Federal Regulations, 2013 CFR
2013-01-01
... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Tree Assistance Program § 760.506 Payment calculations. (a) Payment to an eligible orchardist or nursery tree grower for the cost of replanting or rehabilitating trees, bushes, or vines damaged or lost due to a natural disaster, in excess of 15 percent...
7 CFR 760.506 - Payment calculations.
Code of Federal Regulations, 2012 CFR
2012-01-01
... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Tree Assistance Program § 760.506 Payment calculations. (a) Payment to an eligible orchardist or nursery tree grower for the cost of replanting or rehabilitating trees, bushes, or vines damaged or lost due to a natural disaster, in excess of 15 percent...
7 CFR 760.506 - Payment calculations.
Code of Federal Regulations, 2011 CFR
2011-01-01
... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Tree Assistance Program § 760.506 Payment calculations. (a) Payment to an eligible orchardist or nursery tree grower for the cost of replanting or rehabilitating trees, bushes, or vines damaged or lost due to a natural disaster, in excess of 15 percent...
Revisiting the plasma sheath—dust in plasma sheath
NASA Astrophysics Data System (ADS)
Das, G. C.; Deka, R.; Bora, M. P.
2016-04-01
In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of plasma sheath formed around surfaces of various solid bodies in space, though the results obtained in this work can be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. It is important to note that our calculations are valid only when the amount of dust particles is not sufficient so as to affect the plasma dynamics in the dust-acoustic time scale, but enough to affect the plasma sheath. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisson equation.
Revisiting the plasma sheath—dust in plasma sheath
Das, G. C.; Deka, R.; Bora, M. P.
2016-04-15
In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of plasma sheath formed around surfaces of various solid bodies in space, though the results obtained in this work can be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. It is important to note that our calculations are valid only when the amount of dust particles is not sufficient so as to affect the plasma dynamics in the dust-acoustic time scale, but enough to affect the plasma sheath. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisson equation.
EDITORIAL: Stochasticity in fusion plasmas Stochasticity in fusion plasmas
NASA Astrophysics Data System (ADS)
Unterberg, Bernhard
2010-03-01
Structure formation and transport in stochastic plasmas is a topic of growing importance in many fields of plasma physics from astrophysics to fusion research. In particular, the possibility to control transport in the boundary of confined fusion plasmas by resonant magnetic perturbations has been investigated extensively during recent years. A major research achievement was finding that the intense transient particle and heat fluxes associated with edge localized modes (here type-I ELMs) in magnetically confined fusion plasmas can be mitigated or even suppressed by resonant magnetic perturbation fields. This observation opened up a possible scheme to avoid too large erosion and material damage by such transients in future fusion devices such as ITER. However, it is widely recognized that a more basic understanding is needed to extrapolate the results obtained in present experiments to future fusion devices. The 4th workshop on Stochasticity in Fusion Plasmas was held in Jülich, Germany, from 2 to 4 March 2009. This series of workshops aims at gathering fusion experts from various plasma configurations such as tokamaks, stellarators and reversed field pinches to exchange knowledge on structure formation and transport in stochastic fusion plasmas. The workshops have attracted colleagues from both experiment and theory and stimulated fruitful discussions about the basics of stochastic fusion plasmas. Important papers from the first three workshops in 2003, 2005 and 2007 have been published in previous special issues of Nuclear Fusion (stacks.iop.org/NF/44/i=6, stacks.iop.org/NF/46/i=4 and stacks.iop.org/NF/48/i=2). This special issue comprises contributions presented at the 4th SFP workshop, dealing with the main subjects such as formation of stochastic magnetic layers, energy and particle transport in stochastic magnetic fields, plasma response to external, non-axis-symmetric perturbations and last but not least application of resonant magnetic perturbations for
NASA Astrophysics Data System (ADS)
Robertson, Scott; Sternovsky, Zoltan
2006-10-01
The mesosphere contains nanometer-sized smoke particles that have formed in the vapor trails of meteors and that are thought to be the condensation nuclei for noctilucent clouds. Laboratory dusty plasmas often have the dust particles in a layer at the lower sheath boundary. We examine the possibility of creating in a double-plasma device a smoky plasma in which the particles would be sufficiently small to fill the plasma nearly uniformly while being sufficiently large to exhibit multiple charge states that would distinguish the smoky plasma from one containing heavy negative ions. For example, nanometer sized atomic clusters of Ag (4 nm radius, 10,000 atoms) can be generated in an oven with an inert gas that carries the particles into the plasma chamber. These particles will become charged negatively with about 8 electrons and will then be electrostatically contained by the presheath electric field The confining electric force will also be greater than the ion drag force that could otherwise create a void in the smoke particle density distribution. This plasma would make possible, for example, experiments on the coupling of electrostatic waves to fluid turbulence by the neutral drag force. An acoustic wave propagating in smoky plasma will exert different drag forces on electrons, ions, and smoke particles thus creating a charge-separation electric field that can be measured by potential probes. This coupling may be the origin of electrostatic fluctuations seen by rocket-borne electric field probes in the mesosphere. Supported by the NSF/DOE Plasma Science Initiative.
Surface plasma source with anode layer plasma accelerator.
Dudnikov, Vadim
2012-02-01
Proposed plasma generation system can be used for high current negative ion beam production and for directed deposition by flux of sputtered neutrals and negative ions. The main mechanism of negative ion formation in surface plasma sources is the secondary emission from low work function surface bombarded by a flux of positive ion or neutrals. The emission of negative ions is enhanced significantly by introducing a small amount of cesium or other substance with low ionization potential. In the proposed source are used positive ions generated by Hall drift plasma accelerator (anode layer plasma accelerator or plasma accelerator with insulated channel, with cylindrical or race track configuration of emission slit). The target-emitter is bombarded by the ion beam accelerated in crossed ExB fields. Negative ions are extracted from the target surface with geometrical focusing and are accelerated by negative voltage applied between emitter and plasma, contacting with the plasma accelerator. Hall drift ion source has a special design with a space for passing of the emitted negative ions and sputtered particles through the positive ion source.
Surface plasma source with anode layer plasma accelerator
Dudnikov, Vadim
2012-02-15
Proposed plasma generation system can be used for high current negative ion beam production and for directed deposition by flux of sputtered neutrals and negative ions. The main mechanism of negative ion formation in surface plasma sources is the secondary emission from low work function surface bombarded by a flux of positive ion or neutrals. The emission of negative ions is enhanced significantly by introducing a small amount of cesium or other substance with low ionization potential. In the proposed source are used positive ions generated by Hall drift plasma accelerator (anode layer plasma accelerator or plasma accelerator with insulated channel, with cylindrical or race track configuration of emission slit). The target-emitter is bombarded by the ion beam accelerated in crossed ExB fields. Negative ions are extracted from the target surface with geometrical focusing and are accelerated by negative voltage applied between emitter and plasma, contacting with the plasma accelerator. Hall drift ion source has a special design with a space for passing of the emitted negative ions and sputtered particles through the positive ion source.
2016-06-08
A close-up of twisting plasma above the Sun's surface produced a nice display of turbulence by caused combative magnetic forces (June 7-8, 2016) over a day and a half. The plasma does not break away, but just spins and twists the entire period. Images were taken in extreme ultraviolet light. The mass we observed is part of a longer, darkish filament angling down from the upper left of the frame. Filaments are unstable clouds of plasma suspended above the Sun by magnetic forces. http://photojournal.jpl.nasa.gov/catalog/PIA20739
Langmuir probe in collisionless and collisional plasma including dusty plasma
NASA Astrophysics Data System (ADS)
Bose, Sayak; Kaur, Manjit; Chattopadhyay, P. K.; Ghosh, J.; Saxena, Y. C.; Pal, R.
2017-04-01
Measurements of local plasma parameters in dusty plasma are crucial for understanding the physics issues related to such systems. The Langmuir probe, a small electrode immersed in the plasma, provides such measurements. However, designing of a Langmuir probe system in a dusty plasma environment demands special consideration. First, the probe has to be miniaturized enough so that its perturbation on the ambient dust structure is minimal. At the same time, the probe dimensions must be such that a well-defined theory exists for interpretation of its characteristics. The associated instrumentation must also support the measurement of current collected by the probe with high signal to noise ratio. The most important consideration, of course, comes from the fact that the probes are prone to dust contamination, as the dust particles tend to stick to the probe surface and alter the current collecting area in unpredictable ways. This article describes the design and operation of a Langmuir probe system that resolves these challenging issues in dusty plasma. In doing so, first, different theories that are used to interpret the probe characteristics in collisionless as well as in collisional regimes are discussed, with special emphasis on application. The critical issues associated with the current-voltage characteristics of Langmuir probe obtained in different operating regimes are discussed. Then, an algorithm for processing these characteristics efficiently in presence of ion-neutral collisions in the probe sheath is presented.
PULSION® HP: Tunable, High Productivity Plasma Doping
NASA Astrophysics Data System (ADS)
Felch, S. B.; Torregrosa, F.; Etienne, H.; Spiegel, Y.; Roux, L.; Turnbaugh, D.
2011-01-01
Plasma doping has been explored for many implant applications for over two decades and is now being used in semiconductor manufacturing for two applications: DRAM polysilicon counter-doping and contact doping. The PULSION HP is a new plasma doping tool developed by Ion Beam Services for high-volume production that enables customer control of the dominant mechanism—deposition, implant, or etch. The key features of this tool are a proprietary, remote RF plasma source that enables a high density plasma with low chamber pressure, resulting in a wide process space, and special chamber and wafer electrode designs that optimize doping uniformity.
The menagerie of geospace plasma waves
NASA Technical Reports Server (NTRS)
Shawhan, S. D.
1985-01-01
The sounding rocket and satellite observations of space plasma waves within geospace in the frequency range from millihertz to megahertz are studied. Characteristic frequencies and source mechanisms of the plasma waves are described. The use of the Dynamic Explorer-1 Plasma Wave Instrument spectrograms to represent the plasma wave antenna and receiver system of geospace is examined. The ray tracing technique calculates the path of energy flow; the equations required for the analysis are presented. Cross-correlation of the wave electric and magnetic components provide data used to calculate the wave polarization, the direction of propagation, and the wave distribution function.
Special Activities for Very Special Children.
ERIC Educational Resources Information Center
Bureau of Indian Affairs (Dept. of Interior), Albuquerque, NM.
Developed by 41 Bureau of Indian Affairs special education teachers, this booklet presents 25 teaching activities which they found very helpful in their classrooms. The purpose, materials needed, and procedures are given for each activity. The activities cover the alphabet letters, letter recognition, vocabulary development, sentence structure,…
Basic requirements for plasma sources in medicine
NASA Astrophysics Data System (ADS)
Weltmann, K.-D.; von Woedtke, Th.
2011-07-01
Plasma medicine is a new medical field with first very promising practical studies. However, basic research needs to be done to minimize risk and provide a scientific fundament for medical therapies. Therapeutic application of plasmas at or in the human body is a challenge both for medicine and plasma physics. Today, concepts of tailor-made plasma sources which meet the technical requirements of medical instrumentation are still less developed. To achieve selected effects and to avoid potential risks, it is necessary to know how to control composition and densities of reactive plasma components by external operation parameters. Therefore, a profound knowledge on plasma physics and chemistry must be contributed by physical research. Therapeutic applications required cold, non-thermal plasmas operating at atmospheric pressure. These plasmas are a huge challenge for plasma diagnostics, because usually they are small scale, constricted or filamentary, and transient. Regarding the manageability in everyday medical life, atmospheric pressure plasma jets (APPJ) and dielectric barrier discharges (DBD) are of special interest for medical applications. Working in open air atmospheres, complex plasma chemistry must be expected. Considering that, a great deal of effort combining experimental investigation and modelling is necessary to provide the required knowledge on plasma sources for therapeutic applications.
NASA Technical Reports Server (NTRS)
Van Beaumont, W.; Greenleaf, J. E.
1972-01-01
Discussion of experiments which indicate that under conditions of a constant red cell volume the proportional changes in hematocrit and plasma volume during exercise are never equal. On the basis of direct measurements and calculated changes of plasma volume it is concluded that during maximal exercise there is a small loss of protein from the plasma. It is clear that changes in content of blood constituents can only be evaluated correctly after determination of changes in plasma volume.
Using inverted indices for accelerating LINGO calculations.
Kristensen, Thomas G; Nielsen, Jesper; Pedersen, Christian N S
2011-03-28
The ever growing size of chemical databases calls for the development of novel methods for representing and comparing molecules. One such method called LINGO is based on fragmenting the SMILES string representation of molecules. Comparison of molecules can then be performed by calculating the Tanimoto coefficient, which is called LINGOsim when used on LINGO multisets. This paper introduces a verbose representation for storing LINGO multisets, which makes it possible to transform them into sparse fingerprints such that fingerprint data structures and algorithms can be used to accelerate queries. The previous best method for rapidly calculating the LINGOsim similarity matrix required specialized hardware to yield a significant speedup over existing methods. By representing LINGO multisets in the verbose representation and using inverted indices, it is possible to calculate LINGOsim similarity matrices roughly 2.6 times faster than existing methods without relying on specialized hardware.
Personal Finance Calculations.
ERIC Educational Resources Information Center
Argo, Mark
1982-01-01
Contains explanations and examples of mathematical calculations for a secondary level course on personal finance. How to calculate total monetary cost of an item, monthly payments, different types of interest, annual percentage rates, and unit pricing is explained. (RM)
On April 19, 2010 AIA observed one of the largest prominence eruptions in years. The huge structure erupts, but a great deal of the plasma (hundreds of millions of tons) is unable to escape the gra...
NASA Technical Reports Server (NTRS)
Hintze, Paul E.
2016-01-01
NASA's Kennedy Space Center has developed two solvent-free precision cleaning techniques: plasma cleaning and supercritical carbon dioxide (SCCO2), that has equal performance, cost parity, and no environmental liability, as compared to existing solvent cleaning methods.
Special issue: diagnostics of atmospheric pressure microplasmas
NASA Astrophysics Data System (ADS)
Bruggeman, Peter; Czarnetzki, Uwe; Tachibana, Kunihide
2013-11-01
In recent decades, a strong revival of non-equilibrium atmospheric pressure plasma studies has developed in the form of microplasmas. Microplasmas have typical scales of 1 mm or less and offer a very exciting research direction in the field of plasma science and technology as the discharge physics can be considerably different due to high collisionality and the importance of plasma-surface interaction. These high-pressure small-scale plasmas have a diverse range of physical and chemical properties. This diversity coincides with various applications including light/UV sources [1], material processing [2], chemical analysis [3], material synthesis [4], electromagnetics [5], combustion [6] and even medicine [7]. At atmospheric pressure, large scale plasmas have the tendency to become unstable due to the high collision rates leading to enhanced heating and ionization compared to their low-pressure counterparts. As low-pressure plasmas typically operate in reactors with sizes of tens of centimetres, scaling up the pressure to atmospheric pressure the size of the plasma reduces to typical sizes below 1 mm. A natural approach of stabilizing atmospheric pressure plasmas is thus the use of microelectrode geometries. Traditionally microplasmas have been produced in confined geometries which allow one to stabilize dc excited discharges. This stabilization is intrinsically connected to the large surface-to-volume ratio which enhances heat transfer and losses of charged and excited species to the walls. Currently challenging boundaries are pushed by producing microcavity geometries with dimensions of the order of 1 µm [8]. The subject of this special issue, diagnostics of microplasmas, is motivated by the many challenges in microplasma diagnostics in view of the complex chemistry and strong spatial (and even temporal) gradients of species densities and plasma properties. Atmospheric pressure plasmas have a very long history dating back more than 100 years, with early work of
Determining aminoglycoside dosage and blood levels using a programmable calculator.
Ng, P K
1980-02-01
A programmable calculator procedure for the determination of dosage regimens and steady-state peak and trough levels of aminoglycoside antibiotics is described. The calculator is programmed based on a one-compartment open model and first-order elimination of aminoglycosides. A detailed description of the programs and user instructions are presented. The programs allow calculation of intermittent i.v. infusion dosage regimens and steady-state levels, and adjustment of dosage and dosing interval when measured plasma levels differ significantly from predicted levels. The calculator programs provide a rapid means of predicting and modifying dosage regimens and steady-state plasma levels for aminoglycoside antibiotics.
Autistic Savant Calendar Calculators.
ERIC Educational Resources Information Center
Patti, Paul J.
This study identified 10 savants with developmental disabilities and an exceptional ability to calculate calendar dates. These "calendar calculators" were asked to demonstrate their abilities, and their strategies were analyzed. The study found that the ability to calculate dates into the past or future varied widely among these…
ERIC Educational Resources Information Center
Threlfall, John
2002-01-01
Suggests that strategy choice is a misleading characterization of efficient mental calculation and that teaching mental calculation methods as a whole is not conducive to flexibility. Proposes an alternative in which calculation is thought of as an interaction between noticing and knowledge. Presents an associated teaching approach to promote…
ERIC Educational Resources Information Center
Crow, Tracy, Ed.; Harris, Julia, Ed.
1997-01-01
This journal contains brief descriptions of calculator-active materials that were found using Resource Finder, the searchable online catalog of curriculum resources from the Eisenhower National Clearinghouse (ENC). It features both the calculators themselves and the activity books that are used with them. Among the calculators included are those…
Calculators, Computers, and Classrooms.
ERIC Educational Resources Information Center
Higgins, Jon L.; Kirschner, Vicky
Suggestions for using four-function calculators, programmable calculators, and microcomputers are considered in this collection of 36 articles. The first section contains articles considering general implications for mathematics curricula implied by the freedom calculators offer students from routine computation, enabling them to focus on results…
Special Libraries and the Corporate Political Process.
ERIC Educational Resources Information Center
White, Herbert S.
1984-01-01
This examination of the position of the special library and its services in the corporate setting highlights reasons why libraries are often taken for granted, library's role in corporate financial calculations, generalizations concerning librarian characteristics, and situations that may indicate trouble for a library that is not serving its…
Particle Simulations of Plasma Detachment in VASIMR
NASA Technical Reports Server (NTRS)
Ilin, A. V.; ChangDiaz, F. R.; Squire, J. P.; Breizman, B. N.; Carter, M. D.; Novakovski, S. V.
1999-01-01
The particle simulations in a Variable Specific Impulse Magnetoplasma Rocket (VASIMR) currently include self-consistent calculation of. 1) stationary magnetic field in plasma, 2) ion density and velocity, 3) ion-cyclotron radio-frequency heating, 4) ambipolar electric field. The assumptions of quasineutral and collissionless plasma are based on the range of operating VASIMR parameters. The main motivation for the particle simulation in VASIMR is plasma detachment from the magnetic field in the exhaust area. The plasma detachment is caused mainly by the Larmor radius increase. The plasma beta effect on detachment is observed and investigated as well. The results of particle simulations are compared with those from MHD simulations.
Particle Simulations of Plasma Detachment in VASIMR
NASA Technical Reports Server (NTRS)
Ilin, A. V.; ChangDiaz, F. R.; Squire, J. P.; Breizman, B. N.; Carter, M. D.; Novakovski, S. V.
1999-01-01
The particle simulations in a Variable Specific Impulse Magnetoplasma Rocket (VASIMR) currently include self-consistent calculation of. 1) stationary magnetic field in plasma, 2) ion density and velocity, 3) ion-cyclotron radio-frequency heating, 4) ambipolar electric field. The assumptions of quasineutral and collissionless plasma are based on the range of operating VASIMR parameters. The main motivation for the particle simulation in VASIMR is plasma detachment from the magnetic field in the exhaust area. The plasma detachment is caused mainly by the Larmor radius increase. The plasma beta effect on detachment is observed and investigated as well. The results of particle simulations are compared with those from MHD simulations.
Special Education Resource System.
ERIC Educational Resources Information Center
Kampert, George J.
The guide to the Special Education Resource System (SERS) of the Flour Bluff (Texas) school system contains policies and procedures regarding organization, services, and process of the system. Noted is the SERS purpose of providing information and access to appropriate instructional media and materials for special education personnel. Briefly…
ERIC Educational Resources Information Center
Granstrom, Jane; And Others
1982-01-01
The article reports on the organization and implementation of a "Special Needs Awareness Month" in Quincy, Massachusetts. Noted are the heavy involvement of parents in the multiagency planning committee, and the resulting citywide displays, publications, programs, and publicity on children with special needs. (DB)
ERIC Educational Resources Information Center
Abu-Hamour, Bashir; Al-Hmouz, Hanan
2014-01-01
The purpose of this article is to provide a brief background about special education system in Jordan and particularly describes the present types of programmes and legislation provided within the country to students with special needs, as well as integration movement. Jordan has historically provided a limited number of educational opportunities…
Special Libraries Division. Papers.
ERIC Educational Resources Information Center
International Federation of Library Associations, The Hague (Netherlands).
In "How Special Libraries Use Networks," a paper presented at the 1982 International Federation of Library Associations (IFLA) conference, David R. Bender (United States) advocates cooperation among academic, public, school, and special libraries in the areas of information management, staff services, and acquisition of technology. He…
Perspectives on Sport Specialization.
ERIC Educational Resources Information Center
Watts, Jay
2002-01-01
For high school athletes, the pressure increases each year to specialize and focus on their best sport, and if they do not, they risk being surpassed by other athletes who have focused on one sport. This paper discusses the advantages and disadvantages of sport specialization and looks at the rising danger of club sports for high school athletes.…
ERIC Educational Resources Information Center
Michigan State Dept. of Education, Lansing. Div. of Special Education.
The booklet briefly describes special education employment possibilities in the state of Michigan for 18 areas of exceptionality or specialized service. Discussions usually include suggestions for professional education, description of work performed, and a listing of desirable personal attributes. Individually discussed are the blind and…
Special Education Teacher Persistence
ERIC Educational Resources Information Center
Thorp, Sally A.
2013-01-01
The focus of this study was special education teachers, who remained in the teaching field 5 or more years. Through the use of qualitative mixed-methods study, variables contributing to their longevity were explored. Research indicates that 50% of special education teachers leave the field within five years of employment (Alliance for Education,…
ERIC Educational Resources Information Center
Abu-Hamour, Bashir; Al-Hmouz, Hanan
2014-01-01
The purpose of this article is to provide a brief background about special education system in Jordan and particularly describes the present types of programmes and legislation provided within the country to students with special needs, as well as integration movement. Jordan has historically provided a limited number of educational opportunities…
Handbook of Special Education.
ERIC Educational Resources Information Center
Kauffman, James M., Ed.; Hallahan, Daniel P., Ed.
Intended to serve as a basic reference work for students and professionals in special education, the book contains 34 author contributed chapters concerned with the conceptual foundations of special education, service delivery systems, curriculum and methods, and child and child/environmental management. Chapters have the following titles and…
ERIC Educational Resources Information Center
Buttram, Joan L.; Malloy, William
1990-01-01
Findings from a 3-year study of 33 urban special education programs reveal the following: (1) enrollments are stable; (2) costs are not spiraling; (3) improper referrals have decreased; and (4) few parents are complaining. Offers 4 suggestions to improve special education programs. (MLF)
Challenges Facing Special Education.
ERIC Educational Resources Information Center
Meyen, Edward L., Ed.; And Others
This book presents 17 selected papers from recent issues of the journal, "Focus on Exceptional Children," concerning current and emerging challenges facing the field of special education. The book is organized in two parts. Part 1, "Contemporary Challenges," includes the following articles: "Transitions in Early Childhood Special Education: Issues…
USDA-ARS?s Scientific Manuscript database
This special issue is published for the International Society of Biocatalysis and Biotechnology (ISBB). The ISBB special issue is devoted to all areas of biocatalysis and agricultural biotechnology in which biological systems are developed and/or used for the provision of commercial goods or serv...
ERIC Educational Resources Information Center
Neff, Bonita Dostal
Special events defined as being "newsworthy events" are becoming a way of American life. They are also a means for making a lot of money. Examples of special events that are cited most frequently are often the most minor of events; e.g., the open house, the new business opening day gala, or a celebration of some event in an organization.…
Alaska Special Education Handbook.
ERIC Educational Resources Information Center
Alaska State Dept. of Education and Early Development, Juneau.
This handbook provides guidelines for the operation of local special education programs for Alaskan children with disabilities. It addresses: (1) the Individuals with Disabilities Education Act (IDEA) Amendments of 1997 and basic concepts of special education; (2) identification of students with disabilities, referral, screening programs, and…
Handbook of Special Education.
ERIC Educational Resources Information Center
Kauffman, James M., Ed.; Hallahan, Daniel P., Ed.
Intended to serve as a basic reference work for students and professionals in special education, the book contains 34 author contributed chapters concerned with the conceptual foundations of special education, service delivery systems, curriculum and methods, and child and child/environmental management. Chapters have the following titles and…
2011-03-19
A military color guard opens the 2011 John C. Stennis Area III Track and Field Competitions on March 19. Stennis Space Center is an annual host for the Special Olympics games, which draws special athletes from Hancock, Harrison, Pearl River, and Stone counties and involves hundreds of volunteers and sponsors. The 2011 event was sponsored by the NASA Shared Services Center, located at Stennis.
Challenges Facing Special Education.
ERIC Educational Resources Information Center
Meyen, Edward L., Ed.; And Others
This book presents 17 selected papers from recent issues of the journal, "Focus on Exceptional Children," concerning current and emerging challenges facing the field of special education. The book is organized in two parts. Part 1, "Contemporary Challenges," includes the following articles: "Transitions in Early Childhood Special Education: Issues…
Postmodernism in Special Education.
ERIC Educational Resources Information Center
Gerber, Michael M.
1994-01-01
This paper urges special educators to be wary of borrowing fashionable rhetoric of postmodernism to justify constructivism in the reform of instruction and curriculum without disentangling accompanying constructs and values. There are higher stakes for special education, particularly in national curriculum and testing reform, that accompany…
How Do Calculators Calculate Trigonometric Functions?
ERIC Educational Resources Information Center
Underwood, Jeremy M.; Edwards, Bruce H.
How does your calculator quickly produce values of trigonometric functions? You might be surprised to learn that it does not use series or polynomial approximations, but rather the so-called CORDIC method. This paper will focus on the geometry of the CORDIC method, as originally developed by Volder in 1959. This algorithm is a wonderful…
Plasma formation and expansion in an electrothermal plasma injector
Hurley, J.D.; Bourham, M.A.; Gilligan, J.G.
1994-12-31
The experimental device SIRENS has been used to conduct studies on plasma formation and expansion in electrothermal launchers. The 1-D, time-dependent fluid dynamics code, ODIN, models the energy transport, particle transport, plasma resistivity, plasma viscosity, and the equation-of-state of the source and barrel of the SIRENS experiment. Because electrothermal plasmas are highly collisional (high-density, low-temperature), the plasma is modeled as a viscous fluid, assuming local thermodynamic equilibrium for each cell. The viscous drag forces were varied according to the Reynolds number of each cell. As the Reynolds number increases the modeled drag forces change accordingly, going from laminar to smooth turbulent to rough turbulent. The measured mass loss of the ablating liner (Lexan) in the source section is in good agreement with that predicted by the code. Comparisons between the measured and predicted pressures inside the barrel are in good agreement. The pressure reaches its maximum inside the source at approximately 45 {mu}s, then decreases steadily due to the drop in temperature and density. The plasma flows into the barrel and the pressure profile begins to flatten out and drop as the plasma exits the barrel. The variation of the plasma parameters as a function of the energy input to the source have also been calculated and will be discussed.
NASA Astrophysics Data System (ADS)
Nunes, I.; JET Contributors
2016-01-01
Operation with a Be/W wall at JET (JET-ILW) has an impact on scenario development and energy confinement with respect to the carbon wall (JET-C). The main differences observed were (1) strong accumulation of W in the plasma core and (2) the need to mitigate the divertor target temperature to avoid W sputtering by Be and other low Z impurities and (3) a decrease of plasma energy confinement. A major difference is observed on the pedestal pressure, namely a reduction of the pedestal temperature which, due to profile stiffness the plasma core temperature is also reduced leading to a degradation of the global confinement. This effect is more pronounced in low β N scenarios. At high β N, the impact of the wall on the plasma energy confinement is mitigated by the weaker plasma energy degradation with power relative to the IPB98(y, 2) scaling calculated empirically for a CFC first wall. The smaller tolerable impurity concentration for tungsten (<10-5) compared to that of carbon requires the use of electron heating methods to prevent W accumulation in the plasma core region as well as gas puffing to avoid W entering the plasma core by ELM flushing and reduction of the W source by decreasing the target temperature. W source and the target temperature can also be controlled by impurity seeding. Nitrogen and Neon have been used and with both gases the reduction of the W source and the target temperature is observed. Whilst more experiments with Neon are necessary to assess its impact on energy confinement, a partial increase of plasma energy confinement is observed with Nitrogen, through the increase of edge temperature. The challenge for scenario development at JET is to extend the pulse length curtailed by its transient behavior (W accumulation or MHD), but more importantly by the divertor target temperature limits. Re-optimisation of the scenarios to mitigate the effect of the change of wall materials maintaining high global energy confinement similar to JET-C is
The plasma focus as a tool for plasma-wall-interaction studies
NASA Astrophysics Data System (ADS)
Ramos, G.; Martinez, M.; Herrera, J. J. E.; Castillo, F.
2015-03-01
The study of the interaction of magnetized plasmas with candidate materials for fusion reactors, as for example tungsten, is a main topic in fusion research. Many studies simulate the plasma wall interaction using ion beams, while only a few use plasma simulators. Plasma foci can produce dense magnetized plasmas of deuterium and helium among other species. We used the plasma focus Fuego-Nuevo II, to expose tungsten samples to deuterium and helium plasmas. The samples were analysed by means of SEM, RBS and NRA, evidencing surface erosion, surface melting and retention of deuterium in a shallow surface layer of 250 nm amounting 6.5·1016 D/cm2. The plasma temperature has been measured at the position of the samples using a triple Langmuir probe and compared to calculations of a snowplow model. The modelling of the electrode to reach desired plasma parameters is discussed.
Trapping and dark current in plasma-based accelerators
Schroder, C.B.; Esarey, E.; Shadwick, B.A.; Leemans, W.P.
2004-06-01
The trapping of thermal electrons in a nonlinear plasma wave of arbitrary phase velocity is investigated. The threshold plasma wave amplitude for trapping plasma electrons is calculated, thereby determining the fraction trapped and the expected dark current in a plasma-based accelerator. It is shown that the presence of a laser field (e.g., trapping in the self-modulated regime of the laser wakefield accelerator) increases the trapping threshold. Implications for experimental and numerical laser-plasma studies are discussed.
Singularity embedding method in potential flow calculations
NASA Technical Reports Server (NTRS)
Jou, W. H.; Huynh, H.
1982-01-01
The so-called H-type mesh is used in a finite-element (or finite-volume) calculation of the potential flow past an airfoil. Due to coordinate singularity at the leading edge, a special singular trial function is used for the elements neighboring the leading edge. The results using the special singular elements are compared to those using the regular elements. It is found that the unreasonable pressure distribution obtained by the latter is removed by the embedding of the singular element. Suggestions to extend the present method to transonic cases are given.
Features of spherical torus plasmas
Peng, Y.K.M.; Strickler, D.J.
1985-12-01
The spherical torus is a very small aspect ratio (A < 2) confinement concept obtained by retaining only the indispensable components inboard to the plasma torus. MHD equilibrium calculations show that spherical torus plasmas with safety factor q > 2 are characterized by high toroidal beta (..beta../sub t/ > 0.2), low poloidal beta (..beta../sub p/ < 0.3), naturally large elongation (kappa greater than or equal to 2), large plasma current with I/sub p//(aB/sub t0/) up to about 7 MA/mT, strong paramagnetism (B/sub t//B/sub t0/ > 1.5), and strong plasma helicity (F comparable to THETA). A large near-omnigeneous region is seen at the large-major-radius, bad-curvature region of the plasma in comparison with the conventional tokamaks. These features combine to engender the spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost. Because of its strong paramagnetism and helicity, the spherical torus plasma shares some of the desirable features of spheromak and reversed-field pinch (RFP) plasmas, but with tokamak-like confinement and safety factor q. The general class of spherical tori, which includes the spherical tokamak (q > 1), the spherical pinch (1 > q > O), and the spherical RFP (q < O), have magnetic field configurations unique in comparison with conventional tokamaks and RFPs. 22 refs., 12 figs.
Prenatal radiation exposure: dose calculation.
Scharwächter, C; Röser, A; Schwartz, C A; Haage, P
2015-05-01
The unborn child requires special protection. In this context, the indication for an X-ray examination is to be checked critically. If thereupon radiation of the lower abdomen including the uterus cannot be avoided, the examination should be postponed until the end of pregnancy or alternative examination techniques should be considered. Under certain circumstances, either accidental or in unavoidable cases after a thorough risk assessment, radiation exposure of the unborn may take place. In some of these cases an expert radiation hygiene consultation may be required. This consultation should comprise the expected risks for the unborn while not perturbing the mother or the involved medical staff. For the risk assessment in case of an in-utero x-ray exposition deterministic damages with a defined threshold dose are distinguished from stochastic damages without a definable threshold dose. The occurrence of deterministic damages depends on the dose and the developmental stage of the unborn at the time of radiation. To calculate the risks of an in-utero radiation exposure a three-stage concept is commonly applied. Depending on the amount of radiation, the radiation dose is either estimated, roughly calculated using standard tables or, in critical cases, accurately calculated based on the individual event. The complexity of the calculation thereby increases from stage to stage. An estimation based on stage one is easily feasible whereas calculations based on stages two and especially three are more complex and often necessitate execution by specialists. This article demonstrates in detail the risks for the unborn child pertaining to its developmental phase and explains the three-stage concept as an evaluation scheme. It should be noted, that all risk estimations are subject to considerable uncertainties. • Radiation exposure of the unborn child can result in both deterministic as well as stochastic damage und hitherto should be avoided or reduced to a minimum
Radially inhomogeneous bounded plasmas
NASA Astrophysics Data System (ADS)
Zakeri-Khatir, H.; Aghamir, F. M.
2016-07-01
On the basis of kinetic theory along with self-consistent field equations, the expressions for dielectric tensor of radially inhomogeneous magnetized plasma columns are obtained. The study of dielectric tensor characteristics allows the accurate analysis of the inhomogeneous properties, beyond limitations that exist in the conventional method. Through the Bessel-Fourier transformation, the localized form of material equations in a radially inhomogeneous medium are obtained. In order to verify the integrity of the model and reveal the effect of inhomogeneity, a special case of a cylindrical plasma waveguide completely filled with inhomogeneous magnetized cold plasma was considered. The dispersion relation curves for four families of electromagnetic (EH and HE) and electrostatic (SC and C) modes are obtained and compared with the findings of the conventional model. The numerical analysis indicates that the inhomogeneity effect leads to coupling of electromagnetic and electrostatic modes each having different radial eigen numbers. The study also reveals that the electrostatic modes are more sensitive to inhomogeneous effects than the electromagnetic modes.
Validation of plasma shape reconstruction by Cauchy condition surface method in KSTAR
Miyata, Y.; Suzuki, T.; Ide, S.; Hahn, S. H.; Chung, J.; Bak, J. G.; Ko, W. H.
2014-03-15
Cauchy Condition Surface (CCS) method is a numerical approach to reconstruct the plasma boundary and calculate the quantities related to plasma shape using the magnetic diagnostics in real time. It has been applied to the KSTAR plasma in order to establish the plasma shape reconstruction with the high elongation of plasma shape and the large effect of eddy currents flowing in the tokamak structures for the first time. For applying the CCS calculation to the KSTAR plasma, the effects by the eddy currents and the ferromagnetic materials on the plasma shape reconstruction are studied. The CCS calculation includes the effect of eddy currents and excludes the magnetic diagnostics, which is expected to be influenced largely by ferromagnetic materials. Calculations have been performed to validate the plasma shape reconstruction in 2012 KSTAR experimental campaign. Comparison between the CCS calculation and non-magnetic measurements revealed that the CCS calculation can reconstruct the accurate plasma shape even with a small I{sub P}.
Hypertension in special populations.
Nesbitt, Shawna D
2005-07-01
Hypertension is a multifaceted disease that may present somewhat differently in various populations. It is clear that hypertensive treatment reduces cardiovascular, renal, and cerebrovascular outcomes for all patients, yet recent clinical trial data suggest that some groups may benefit more than others from specific drug intervention. Furthermore, these data justify specific approaches for some special populations. This article reviews important features of the presentation, rationale for treatment, and treatment recommendations for the treatment of hypertension in special populations. The special populations addressed include diabetic patients, the elderly, and women.
Baker, W.R.; Brathenahl, A.; Furth, H.P.
1962-04-10
A device for producing a confined high temperature plasma is described. In the device the concave inner surface of an outer annular electrode is disposed concentrically about and facing the convex outer face of an inner annular electrode across which electrodes a high potential is applied to produce an electric field there between. Means is provided to create a magnetic field perpendicular to the electric field and a gas is supplied at reduced pressure in the area therebetween. Upon application of the high potential, the gas between the electrodes is ionized, heated, and under the influence of the electric and magnetic fields there is produced a rotating annular plasma disk. The ionized plasma has high dielectric constant properties. The device is useful as a fast discharge rate capacitor, in controlled thermonuclear research, and other high temperature gas applications. (AEC)
Gow, J.D.; Wilcox, J.M.
1961-12-26
A device is designed for producing and confining highenergy plasma from which neutrons are generated in copious quantities. A rotating sheath of electrons is established in a radial electric field and axial magnetic field produced within the device. The electron sheath serves as a strong ionizing medium to gas introdueed thereto and also functions as an extremely effective heating mechanism to the resulting plasma. In addition, improved confinement of the plasma is obtained by ring magnetic mirror fields produced at the ends of the device. Such ring mirror fields are defined by the magnetic field lines at the ends of the device diverging radially outward from the axis of the device and thereafter converging at spatial annular surfaces disposed concentrically thereabout. (AFC)
Trajectory structures in turbulent plasmas
Vlad, Madalina; Spineanu, Florin
2006-11-03
Particle stochastic advection in two dimensional divergence free velocity fields is studied. The special statistical properties of this process (non-Gaussian distribution, memory effects and quasi-coherent behavior) are determined using a new approach, the nested subensemble method. The effect of the statistics of trajectories on the evolution of drift turbulence in magnetized plasmas is studied. It essentialy consists in the tendency of structure formation.
Calculators: managing with technology.
Goldstone, L
1980-07-25
When the calculators do the calculating, the managers can do the managing. Len Goldstone of the UMIST Department of Management Sciences examines how close we are to that ideal. There are, he says, calculators of three levels of complexity and price, but warns that tomorrow's manager may find even the most sophisticated of today's instruments clumsy compared to the mini-computers now being developed.
Research in Dense Plasma Atomic Physics.
1984-04-19
atomic properties up to r of order two (for neon). Debye - Huckel theory is not a meaningful approximation in strongly coupled plasmas. Nor can we...consequently one can expect that the Debye - Huckel theory would be inadequate for the description of plasma properties. This is demonstrated by...the Debye - Huckel (DH) and ion-sphere (IS) calculations when 13 < r < 1 Models We consider an ion of nuclear charge Z in a plasma in which the average
A model of electron collecting plasma contractors
NASA Technical Reports Server (NTRS)
Davis, V. A.; Katz, I.; Mandell, M. J.; Parks, D. E.
1989-01-01
A model of plasma contractors is being developed, which can be used to describe electron collection in a laboratory test tank and in the space environment. To validate the model development, laboratory experiments are conducted in which the source plasma is separated from the background plasma by a double layer. Model calculations show that an increase in ionization rate with potential produces a steep rise in collected current with increasing potential.
A model of electron collecting plasma contractors
NASA Technical Reports Server (NTRS)
Davis, V. A.; Katz, I.; Mandell, M. J.; Parks, D. E.
1989-01-01
A model of plasma contractors is being developed, which can be used to describe electron collection in a laboratory test tank and in the space environment. To validate the model development, laboratory experiments are conducted in which the source plasma is separated from the background plasma by a double layer. Model calculations show that an increase in ionization rate with potential produces a steep rise in collected current with increasing potential.
Evapotranspiration Calculator Desktop Tool
The Evapotranspiration Calculator estimates evapotranspiration time series data for hydrological and water quality models for the Hydrologic Simulation Program - Fortran (HSPF) and the Stormwater Management Model (SWMM).
Multiphase flow calculation software
Fincke, James R.
2003-04-15
Multiphase flow calculation software and computer-readable media carrying computer executable instructions for calculating liquid and gas phase mass flow rates of high void fraction multiphase flows. The multiphase flow calculation software employs various given, or experimentally determined, parameters in conjunction with a plurality of pressure differentials of a multiphase flow, preferably supplied by a differential pressure flowmeter or the like, to determine liquid and gas phase mass flow rates of the high void fraction multiphase flows. Embodiments of the multiphase flow calculation software are suitable for use in a variety of applications, including real-time management and control of an object system.
1980-11-01
nomograms, and a programmable calculator . Appendices present worksheets, example problems, procedures for determining meteorological inputs, a procedure for determining evaporative source strength, and other items.
NASA Astrophysics Data System (ADS)
Weber, L. F.
1983-01-01
Plasma displays use the physical phenomena of the gas discharge and are frequently called gas discharge displays. This is a rather mature display technology that has seen commercial success over a wide size range, from small single digits to one meter diagonal graphics displays having 2 million pixels. Plasma displays currently enjoy the dominant position in large flat panel display technologies. They are likely to maintain that position in at least the next five years because of the many properties of the gas discharge ideally suited for flat panel matrix displays.
Online Learning: Special Report.
ERIC Educational Resources Information Center
Training, 1999
1999-01-01
This special section includes "The View from the Middle" (Dick Schaaf); "Crossing the Channel" (Dawn Garrett); and "Bandwidth Basics" (Dick Schaaf). Sidebars look at bandwidth and management issues as well as courseware development. (JOW)
Special parallel processing workshop
1994-12-01
This report contains viewgraphs from the Special Parallel Processing Workshop. These viewgraphs deal with topics such as parallel processing performance, message passing, queue structure, and other basic concept detailing with parallel processing.
Specialized Investment Services
ERIC Educational Resources Information Center
Burgess, Robert S.
1970-01-01
The informational needs of the investing public should be met by the public library. Suggestions for specialized investment information services with broad appeal, technical charts, and advisory services which public libraries might consider purchasing. (JS)
2011-03-24
There something special going on in the nearby Circinus galaxy, as revealed by this image from NASA WISE telescope. The Circinus galaxy is located in the constellation of Circinus and is obscured by the plane of our Milky Way galaxy.
ERIC Educational Resources Information Center
Jones, Hilda B.
1973-01-01
Granite School District, a suburb of Salt Lake City, Utah, has a staff of 349 teachers and other professional personnel who provide career education and job experience for more than 5,000 special children. (DS)
ERIC Educational Resources Information Center
Foster, Barbara
1974-01-01
Israel is sprinkled with a noteworthy representation of special libraries which run the gamut from modest kibbutz efforts to highly technical scientific and humanities libraries. A few examples are discussed here. (Author/CH)
NASA Astrophysics Data System (ADS)
Mayyasi-Matta, Majd; Mendillo, M.; Galand, M.; Moore, L.; Withers, P.
2013-10-01
Ion and electron temperatures in the ionosphere of Mars affect plasma densities. These quantities vary with altitude and time of day. Modeling results are used to interpret existing measurements and to support anticipated MAVEN measurements. A 1D fluid model of the Martian ionosphere has been coupled to a kinetic supra-thermal electron transport model in order to self-consistently calculate ion and electron densities and temperatures. The models include diurnal variations, revealing hundreds of Kelvin changes in dayside electron and ion temperatures at fixed altitude. The models treat each ion species separately, revealing hundreds of Kelvin differences between H+ and O2+ temperatures. Consistent with previous studies using single-ion plasma, solar EUV heating alone is insufficient to heat the thermal electrons and ion species to observed temperatures, indicating the presence of additional heating sources.
Instabilities in uranium plasma.
NASA Technical Reports Server (NTRS)
Tidman, D. A.
1971-01-01
The nonlinear evolution of unstable sound waves in a uranium plasma has been calculated using a multiple time-scale asymptotic expansion scheme. The fluid equations used include the fission power density, radiation diffusion, and the effects of the changing degree of ionization of the uranium atoms. The nonlinear growth of unstable waves is shown to be limited by mode coupling to shorter wavelength waves which are damped by radiation diffusion. This mechanism limits the wave pressure fluctuations to values of order delta P/P equal to about .00001 in the plasma of a typical gas-core nuclear rocket engine. The instability is thus not expected to present a control problem for this engine.
Instabilities in uranium plasma.
NASA Technical Reports Server (NTRS)
Tidman, D. A.
1971-01-01
The nonlinear evolution of unstable sound waves in a uranium plasma has been calculated using a multiple time-scale asymptotic expansion scheme. The fluid equations used include the fission power density, radiation diffusion, and the effects of the changing degree of ionization of the uranium atoms. The nonlinear growth of unstable waves is shown to be limited by mode coupling to shorter wavelength waves which are damped by radiation diffusion. This mechanism limits the wave pressure fluctuations to values of order delta P/P equal to about .00001 in the plasma of a typical gas-core nuclear rocket engine. The instability is thus not expected to present a control problem for this engine.
1981-10-01
TI-59 programmable calculator . The following calculations are made by the program series: Log volume by Smalian’s Formula; Lumber Recovery Factor...computer field, there is a general lack of special purpose programs that are well documented and easy to use. The main competitors in the programmable ... calculator market do offer large numbers of documented program for many applications. The applications that this publication addresses, however, are
Stark broadening data for stellar plasma research.
NASA Astrophysics Data System (ADS)
Dimitrijević, M. S.
Results of an effort to provide to astrophysicists and physicists an as much as possible complete set of Stark broadening parameters needed for stellar opacity calculations, stellar atmosphere modelling, abundance determinations and diagnostics of different plasmas in astrophysics, physics and plasma technology, are presented. Stark broadening has been considered within the semiclassical perturbation, and the modified semiempirical approaches.
Myer, Gregory D.; Jayanthi, Neeru; Difiori, John P.; Faigenbaum, Avery D.; Kiefer, Adam W.; Logerstedt, David; Micheli, Lyle J.
2015-01-01
Context: There is increased growth in sports participation across the globe. Sports specialization patterns, which include year-round training, participation on multiple teams of the same sport, and focused participation in a single sport at a young age, are at high levels. The need for this type of early specialized training in young athletes is currently under debate. Evidence Acquisition: Nonsystematic review. Study Design: Clinical review. Level of Evidence: Level 4. Conclusion: Sports specialization is defined as year-round training (greater than 8 months per year), choosing a single main sport, and/or quitting all other sports to focus on 1 sport. Specialized training in young athletes has risks of injury and burnout, while the degree of specialization is positively correlated with increased serious overuse injury risk. Risk factors for injury in young athletes who specialize in a single sport include year-round single-sport training, participation in more competition, decreased age-appropriate play, and involvement in individual sports that require the early development of technical skills. Adults involved in instruction of youth sports may also put young athletes at risk for injury by encouraging increased intensity in organized practices and competition rather than self-directed unstructured free play. Strength-of-Recommendation Taxonomy (SORT): C. PMID:26502420
Numerical Study on Plasma Jet and Particle Behavior in Multi-arc Plasma Spraying
NASA Astrophysics Data System (ADS)
Bobzin, K.; Öte, M.; Schein, J.; Zimmermann, S.
2017-06-01
Plasma jet and particle behavior in conventional single-arc plasma spraying has been subject to intensive numerical research. However, multi-arc plasma spraying is a different case which has yet to be investigated more closely. Numerical models developed to investigate the characteristics of multi-arc plasma spraying (plasma generator, plasma jet, and plasma-particle interaction models) were introduced in previous publications by the authors. The plasma generator and plasma jet models were already validated by comparing calculated plasma temperatures with results of emission spectroscopic computed tomography. In this study, the above-mentioned models were subjected to further validation effort. Calculated particle in-flight characteristics were compared with those determined by means of particle diagnostics and high-speed videography. The results show very good agreement. The main aim of the current publication is to derive conclusions regarding the general characteristics of plasma jet and particle in-flight behavior in multi-arc plasma spraying. For this purpose, a numerical parameter study is conducted in which the validated models are used to allow variations in the process parameters. Results regarding plasma jet/particle in-flight temperatures and velocities are presented. Furthermore, the general characteristics of plasma jet and particle behavior in multi-arc plasma spraying are discussed and explained. This contributes to better understanding of the multi-arc plasma spraying process, in particular regarding the injection behavior of particles into hot regions of the plasma jet. Finally, an example test case showing a possible practical application area of the models is introduced.
Modeling ion extraction from a free-plasma surface with a flexible conformal mesh
NASA Astrophysics Data System (ADS)
Humphries, Stanley
2005-04-01
This paper describes a new method for numerical modeling of extraction of high-current ion beams from a plasma source. The challenge in the application is to satisfy simultaneously requirements for space-charge-limited flow and uniform ion flux. The plasma surface must assume a special shape that is not known in advance. The method involves the use of finite-element techniques coupled with a dynamic conformal mesh. Starting from an initial estimate, the flexible mesh is shifted to achieve uniform flux over the emission surface. The approach achieves high accuracy and has the versatility to handle complex emission surfaces in gridded guns. In contrast to trial-and-error approaches, the method proceeds directly to the optimum solution. The technique can also be applied to determine cathode shapes for uniform-flux electron guns. Benchmark calculations using the Trak two-dimensional ray-tracing code are described. The program automatically carries out the surface search.
NASA Astrophysics Data System (ADS)
Ribière, M.; Karabourniotis, D.; Chéron, B. G.
2009-04-01
During the relaxation of the plasma plume generated by laser ablation of an aluminum target, a pronounced intensity enhancement is observed at the central wavelength of the 396.15 nm self-reversed resonant line. This spectral special feature is analyzed and related to the interaction of the plasma edge with the background air excited by the shockwave, prompt electrons, and extreme ultraviolet radiation produced at the earliest times of the ablation. In this article, the electron density, the aluminum ground state, and resonant level populations are determined from the fitting of the 396.15 nm calculated line profile to the experimental one at two background pressures (100 and 1000 Pa). The evolution of these densities is derived from experiments performed at delays, after the laser pulse arrival, ranging from 120 to 180 ns.
End loss analyzer system for measurements of plasma flux at the C-2U divertor electrode
NASA Astrophysics Data System (ADS)
Griswold, M. E.; Korepanov, S.; Thompson, M. C.
2016-11-01
An end loss analyzer system consisting of electrostatic, gridded retarding-potential analyzers and pyroelectric crystal bolometers was developed to characterize the plasma loss along open field lines to the divertors of C-2U. The system measures the current and energy distribution of escaping ions as well as the total power flux to enable calculation of the energy lost per escaping electron/ion pair. Special care was taken in the construction of the analyzer elements so that they can be directly mounted to the divertor electrode. An attenuation plate at the entrance to the gridded retarding-potential analyzer reduces plasma density by a factor of 60 to prevent space charge limitations inside the device, without sacrificing its angular acceptance of ions. In addition, all of the electronics for the measurement are isolated from ground so that they can float to the bias potential of the electrode, 2 kV below ground.
Cluster virial expansion of the equation of state for hydrogen plasma with e -H2 contributions
NASA Astrophysics Data System (ADS)
Omarbakiyeva, Y. A.; Reinholz, H.; Röpke, G.
2015-04-01
The equation of state of partially ionized hydrogen plasma is considered with special focus on the contribution of the e -H2 interaction. Traditional semiempirical concepts such as the excluded volume are improved using microscopic approaches to treat the e -H2 problem. Within a cluster virial expansion, the Beth-Uhlenbeck formula is applied to infer the contribution of bound and scattering states to the temperature-dependent second virial coefficient. The scattering states are calculated using the phase expansion method for the polarization interaction that incorporates experimental data for the e -H2 scattering cross section. We present results for the scattering phase shifts, differential scattering cross sections, and the second virial coefficient due to the e -H2 interaction. The influence of this interaction on the composition of the partially ionized hydrogen plasma is confined to the parameter range where both the H2 and the free-electron components are abundant.
End loss analyzer system for measurements of plasma flux at the C-2U divertor electrode
Griswold, M. E. Korepanov, S.; Thompson, M. C.
2016-11-15
An end loss analyzer system consisting of electrostatic, gridded retarding-potential analyzers and pyroelectric crystal bolometers was developed to characterize the plasma loss along open field lines to the divertors of C-2U. The system measures the current and energy distribution of escaping ions as well as the total power flux to enable calculation of the energy lost per escaping electron/ion pair. Special care was taken in the construction of the analyzer elements so that they can be directly mounted to the divertor electrode. An attenuation plate at the entrance to the gridded retarding-potential analyzer reduces plasma density by a factor of 60 to prevent space charge limitations inside the device, without sacrificing its angular acceptance of ions. In addition, all of the electronics for the measurement are isolated from ground so that they can float to the bias potential of the electrode, 2 kV below ground.
NASCAP/LEO calculations of current collection
NASA Technical Reports Server (NTRS)
Mandell, Myron J.; Katz, Ira; Davis, Victoria A.; Kuharski, Robert A.
1990-01-01
NASCAP/LEO is a 3-dimensional computer code for calculating the interaction of a high-voltage spacecraft with the cold dense plasma found in Low Earth Orbit. Although based on a cubic grid structure, NASCAP/LEO accepts object definition input from standard computer aided design (CAD) programs so that a model may be correctly proportioned and important features resolved. The potential around the model is calculated by solving the finite element formulation of Poisson's equation with an analytic space charge function. Five previously published NASCAP/LEO calculations for three ground test experiments and two space flight experiments are presented. The three ground test experiments are a large simulated panel, a simulated pinhole, and a 2-slit experiment with overlapping sheaths. The two space flight experiments are a solar panel biased up to 1000 volts, and a rocket-mounted sphere biased up to 46 kilovolts. In all cases, the authors find good agreement between calculation and measurement.
NASCAP/LEO calculations of current collection
NASA Astrophysics Data System (ADS)
Mandell, Myron J.; Katz, Ira; Davis, Victoria A.; Kuharski, Robert A.
1990-12-01
NASCAP/LEO is a 3-dimensional computer code for calculating the interaction of a high-voltage spacecraft with the cold dense plasma found in Low Earth Orbit. Although based on a cubic grid structure, NASCAP/LEO accepts object definition input from standard computer aided design (CAD) programs so that a model may be correctly proportioned and important features resolved. The potential around the model is calculated by solving the finite element formulation of Poisson's equation with an analytic space charge function. Five previously published NASCAP/LEO calculations for three ground test experiments and two space flight experiments are presented. The three ground test experiments are a large simulated panel, a simulated pinhole, and a 2-slit experiment with overlapping sheaths. The two space flight experiments are a solar panel biased up to 1000 volts, and a rocket-mounted sphere biased up to 46 kilovolts. In all cases, the authors find good agreement between calculation and measurement.
Calculations of Electron Attachment and Recombination in a Hydrogen Plasma.
1991-02-01
two beams is measured at two places in the interaction region and the effective collision area , F, is determined. The cross section for recombination...electron beam currents and velocities respectively, L is the length of the interaction region and F is the effective collision area . The energy in the...is also of consider- 120 able practical importance in areas such as combustion,’ extraterrestrial atmospheres, 2 vacuum-uv laser sources, 3 laser-based
Space-plasma campaign on UCLA's Large Plasma Device (LAPD)
NASA Astrophysics Data System (ADS)
Koepke, M. E.; Finnegan, S. M.; Knudsen, D. J.; Vincena, S.
2007-05-01
Knudsen [JGR, 1996] describes a potential role for stationary Alfvén (StA) waves in auroral arcs' frequency dependence. Magnetized plasmas are predicted to support electromagnetic perturbations that are static in a fixed frame if there is uniform background plasma convection. These stationary waves should not be confused with standing waves that oscillate in time with a fixed, spatially varying envelope. Stationary waves have no time variation in the fixed frame. In the drifting frame, there is an apparent time dependence as plasma convects past fixed electromagnetic structures. We describe early results from an experimental campaign to reproduce in the lab the basic conditions necessary for the creation of StA waves, namely quasi-steady-state convection across magnetic field-aligned current channels. We show that an off-axis, fixed channel of electron current (and depleted density) is created in the Large Plasma Device Upgrade (LAPD) at UCLA, using a small, heated, oxide-coated electrode at one plasma-column end and we show that the larger plasma column rotates about its cylindrical axis from a radial electric field imposed by a special termination electrode on the same end. Initial experimentation with plasma-rotation-inducing termination electrodes began in May 2006 in the West Virginia Q Machine, leading to two designs that, in January 2007, were tested in LAPD. The radial profile of azimuthal velocity was consistent with predictions of rigid-body rotation. Current-channel experiments in LAPD, in August 2006, showed that inertial Alfvén waves could be concentrated in an off-axis channel of electron current and depleted plasma density. These experimental results will be presented and discussed. This research is supported by DOE and NSF.
[Understanding dosage calculations].
Benlahouès, Daniel
2016-01-01
The calculation of dosages in paediatrics is the concern of the whole medical and paramedical team. This activity must generate a minimum of risks in order to prevent care-related adverse events. In this context, the calculation of dosages is a practice which must be understood by everyone.
Electron beam dose calculations.
Hogstrom, K R; Mills, M D; Almond, P R
1981-05-01
Electron beam dose distributions in the presence of inhomogeneous tissue are calculated by an algorithm that sums the dose distribution of individual pencil beams. The off-axis dependence of the pencil beam dose distribution is described by the Fermi-Eyges theory of thick-target multiple Coulomb scattering. Measured square-field depth-dose data serve as input for the calculations. Air gap corrections are incorporated and use data from'in-air' measurements in the penumbra of the beam. The effective depth, used to evaluate depth-dose, and the sigma of the off-axis Gaussian spread against depth are calculated by recursion relations from a CT data matrix for the material underlying individual pencil beams. The correlation of CT number with relative linear stopping power and relative linear scattering power for various tissues is shown. The results of calculations are verified by comparison with measurements in a 17 MeV electron beam from the Therac 20 linear accelerator. Calculated isodose lines agree nominally to within 2 mm of measurements in a water phantom. Similar agreement is observed in cork slabs simulating lung. Calculations beneath a bone substitute illustrate a weakness in the calculation. Finally a case of carcinoma in the maxillary antrum is studied. The theory suggests an alternative method for the calculation of depth-dose of rectangular fields.
ERIC Educational Resources Information Center
Phillips-Bey, Carol K.
2004-01-01
This article describes TI-73 calculator activities appropriate for middle school students. It was found that the use of the calculator allowed for higher-level thinking and a richer exploration of mathematical ideas by students. [Included with this article are "Dice Roll Worksheet" and "Transforming Tree Worksheet".] (Contains 9 figures.)
NASA Technical Reports Server (NTRS)
Steurer, Wolfgang
1992-01-01
This process employs a thermal plasma for the separation and production of oxygen and metals. It is a continuous process that requires no consumables and relies entirely on space resources. The almost complete absence of waste renders it relatively clean. It can be turned on or off without any undesirable side effects or residues. The prime disadvantage is its high power consumption.
Herlitz, H.G.
1986-11-01
This paper describes the uses of plasma technology for the thermal destruction of hazardous wastes such as PCBs, dioxins, hydrocarbons, military chemicals and biological materials; for metals recovery from steel making dusts. One advantage of the process is that destruction of wastes can be carried out on site. Systems in several countries use the excess thermal energy for district heating.
Furth, H.P.; Goldston, R.J.; Zweben, S.J. . Plasma Physics Lab.); Sigmar, D.J. )
1990-10-01
The fraction of fusion-reaction energy that is released in energetic charged ions, such as the alpha particles of the D-T reaction, can be thermalized within the reacting plasma and used to maintain its temperature. This mechanism facilitates the achievement of very high energy-multiplication factors Q, but also raises a number of new issues of confinement physics. To ensure satisfactory reaction operation, three areas of energetic-ion interaction need to be addressed: single-ion transport in imperfectly symmetric magnetic fields or turbulent background plasmas; energetic-ion-driven (or stabilized) collective phenomena; and fusion-heat-driven collective phenomena. The first of these topics is already being explored in a number of tokamak experiments, and the second will begin to be addressed in the D-T-burning phase of TFTR and JET. Exploration of the third topic calls for high-Q operation, which is a goal of proposed next-generation plasma-burning projects. Planning for future experiments must take into consideration the full range of plasma-physics and engineering R D areas that need to be addressed on the way to a fusion power demonstration.
Current in wave driven plasmas
Karney, C.F.F.; Fisch, N.J.
1985-06-01
A theory for the generation of current in a toroidal plasma by radio-frequency waves is presented. The effect of an opposing electric field is included, allowing the case of time varying currents to be studied. The key quantities that characterize this regime are identified and numerically calculated. Circuit equations suitable for use in ray-tracing and transport codes are given.
Noordzij, Marlies; Dekker, Friedo W; Zoccali, Carmine; Jager, Kitty J
2011-01-01
The sample size is the number of patients or other experimental units that need to be included in a study to answer the research question. Pre-study calculation of the sample size is important; if a sample size is too small, one will not be able to detect an effect, while a sample that is too large may be a waste of time and money. Methods to calculate the sample size are explained in statistical textbooks, but because there are many different formulas available, it can be difficult for investigators to decide which method to use. Moreover, these calculations are prone to errors, because small changes in the selected parameters can lead to large differences in the sample size. This paper explains the basic principles of sample size calculations and demonstrates how to perform such a calculation for a simple study design.
Plasma vertical stabilisation in ITER
NASA Astrophysics Data System (ADS)
Gribov, Y.; Kavin, A.; Lukash, V.; Khayrutdinov, R.; Huijsmans, G. T. A.; Loarte, A.; Snipes, J. A.; Zabeo, L.
2015-07-01
This paper describes the progress in analysis of the ITER plasma vertical stabilisation (VS) system since its design review in 2007-2008. Two indices characterising plasma VS were studied. These are (1) the maximum value of plasma vertical displacement due to free drift that can be stopped by the VS system and (2) the maximum root mean square value of low frequency noise in the dZ/dt measurement signal used in the VS feedback loop. The first VS index was calculated using the PET code for 15 MA plasmas with the nominal position and shape. The second VS index was studied with the DINA code in the most demanding simulations for plasma magnetic control of 15 MA scenarios with the fastest plasma current ramp-up and early X-point formation, the fastest plasma current ramp-down in a divertor configuration, and an H to L mode transition at the current flattop. The studies performed demonstrate that the VS in-vessel coils, adopted recently in the baseline design, significantly increase the range of plasma controllability in comparison with the stabilising systems VS1 and VS2, providing operating margins sufficient to achieve ITER's goals specified in the project requirements. Additionally two sets of the DINA code simulations were performed with the goal of assessment of the capability of the PF system with the VS in-vessel coils: (i) to control the position of runaway electrons generated during disruptions in 15 MA scenarios and (ii) to trigger ELMs in H-mode plasmas of 7.5 MA/2.65 T scenarios planned for the early phase of ITER operation. It was also shown that ferromagnetic structures of the vacuum vessel (ferromagnetic inserts) and test blanket modules insignificantly affect the plasma VS.
Plasma in the Jovian magnetosphere
NASA Technical Reports Server (NTRS)
Goertz, C. K.
1975-01-01
It is shown that the plasma in Jupiter's ionosphere is collisionless above a certain level. In the outer magnetosphere, where the rotational force dominates the gravitational force, the collisionless plasma has a beam-like distribution and gives rise to a two-stream instability. This leads to trapping of plasma in the centrifugally dominated region of the magnetosphere. Plasma is lost by recombination. Equilibrium-trapped particle densities are calculated by requiring a balance between trapping by wave-particle interaction and loss by recombination. The results are compared with recent observations from Pioneer 10. It is suggested that the observations require an unexplained ion-heating mechanism. Some consequences of the model are discussed.
[Hyponatremia: effective treatment based on calculated outcomes].
Vervoort, G; Wetzels, J F M
2006-09-30
A 78-year-old man was treated for symptomatic hyponatremia. Despite administration of an isotonic NaCl 0.9% solution, plasma sodium remained unchanged due to high concentrations of sodium and potassium in the urine. After infusion of a hypertonic NaCl solution, a satisfactory increase in plasma sodium was reached and symptoms resolved gradually. The hyponatremia was found to be caused by hypothyroidism, which was treated. A 70-year-old female was admitted to the hospital with loss of consciousness and hyponatremia. She was treated initially with a hypertonic NaCl 2.5% solution, which resulted in a steady increase in plasma sodium and a resolution of symptoms. Treatment was changed to an isotonic NaCl 0.9% infusion to attenuate the rise of serum sodium. Nevertheless plasma sodium increased too rapidly due to increased diuresis and reduced urinary sodium and potassium excretion. A slower increase in plasma sodium was achieved by administering a glucose 5% infusion. Hyponatremia is frequently observed in hospitalised patients. It should be treated effectively, and the rate of correction should be adapted to the clinical situation. Effective treatment is determined by calculating changes in effective osmoles and the resulting changes in the distribution of water over extra- and intracellular spaces. Changes in urine production and urinary excretion of sodium and potassium should be taken into account.
Calculation reliability in vehicle accident reconstruction.
Wach, Wojciech
2016-06-01
The reconstruction of vehicle accidents is subject to assessment in terms of the reliability of a specific system of engineering and technical operations. In the article [26] a formalized concept of the reliability of vehicle accident reconstruction, defined using Bayesian networks, was proposed. The current article is focused on the calculation reliability since that is the most objective section of this model. It is shown that calculation reliability in accident reconstruction is not another form of calculation uncertainty. The calculation reliability is made dependent on modeling reliability, adequacy of the model and relative uncertainty of calculation. All the terms are defined. An example is presented concerning the analytical determination of the collision location of two vehicles on the road in the absence of evidential traces. It has been proved that the reliability of this kind of calculations generally does not exceed 0.65, despite the fact that the calculation uncertainty itself can reach only 0.05. In this example special attention is paid to the analysis of modeling reliability and calculation uncertainty using sensitivity coefficients and weighted relative uncertainty.
Thomson scattering from laser plasmas
Moody, J D; Alley, W E; De Groot, J S; Estabrook, K G; Glenzer, S H; Hammer, J H; Jadaud, J P; MacGowan, B J; Rozmus, W; Suter, L J; Williams, E A
1999-01-12
Thomson scattering has recently been introduced as a fundamental diagnostic of plasma conditions and basic physical processes in dense, inertial confinement fusion plasmas. Experiments at the Nova laser facility [E. M. Campbell et al., Laser Part. Beams 9, 209 (1991)] have demonstrated accurate temporally and spatially resolved characterization of densities, electron temperatures, and average ionization levels by simultaneously observing Thomson scattered light from ion acoustic and electron plasma (Langmuir) fluctuations. In addition, observations of fast and slow ion acous- tic waves in two-ion species plasmas have also allowed an independent measurement of the ion temperature. These results have motivated the application of Thomson scattering in closed-geometry inertial confinement fusion hohlraums to benchmark integrated radiation-hydrodynamic modeling of fusion plasmas. For this purpose a high energy 4{omega} probe laser was implemented recently allowing ultraviolet Thomson scattering at various locations in high-density gas-filled hohlraum plasmas. In partic- ular, the observation of steep electron temperature gradients indicates that electron thermal transport is inhibited in these gas-filled hohlraums. Hydrodynamic calcula- tions which include an exact treatment of large-scale magnetic fields are in agreement with these findings. Moreover, the Thomson scattering data clearly indicate axial stagnation in these hohlraums by showing a fast rise of the ion temperature. Its timing is in good agreement with calculations indicating that the stagnating plasma will not deteriorate the implosion of the fusion capsules in ignition experiments.
Inertial currents in isotropic plasma
NASA Technical Reports Server (NTRS)
Heinemann, M.; Erickson, G. M.; Pontius, D. H., Jr.
1994-01-01
The magnetospheric convection electric field contributes to Birkeland currents. The effects of the field are to polarize the plasma by displacing the bounce paths of the ions from those of electrons, to redistribute the pressure so that it is not constant along magnetic field lines, and to enhance the pressure gradient by the gradient of the bulk speed. Changes in the polarization charge during the convection of the plasma are neutralized by electrons in the form of field-aligned currents that close through the ionosphere. The pressure drives field-aligned currents through its gradient in the same manner as in quasi-static plasmas, but with modifications that are important if the bulk speed is of the order of the ion thermal speed; the variations in the pressure along field lines are maintained by a weak parallel potential drop. These effects are described in terms of the field-aligned currents in steady state, isotropic, MHD plasma. Solutions are developed by taking the MHD limit ot two-fluid solutions and illustrated in the special case of Maxwellian plasma for which the temperature is constant along magnetic field lines. The expression for the Birkeland current density is a generalization of Vasyliunas' expression for the field-aligned current density in quasi-static plasma and provides a unifying expression when both pressure gradients and ion inertia operate simultaneously as sources of field-aligned currents. It contains a full account of different aspects of the ion flow (parallel and perpendicular velocity and vorticity) that contribute to the currents. Contributions of ion inertia to field-aligned currents will occur in regions of strong velocity shear, electric field reversal, or large gradients in the parallel velocity or number density, and may be important in the low-latitude boundary layer, plasma sheet boundary layer, and the inner edge region of the plasma sheet.
7 CFR 760.210 - Honeybee payment calculations.
Code of Federal Regulations, 2013 CFR
2013-01-01
... 7 Agriculture 7 2013-01-01 2013-01-01 false Honeybee payment calculations. 760.210 Section 760.210... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program § 760.210 Honeybee payment calculations. (a) An eligible honeybee producer may...
7 CFR 760.210 - Honeybee payment calculations.
Code of Federal Regulations, 2011 CFR
2011-01-01
... 7 Agriculture 7 2011-01-01 2011-01-01 false Honeybee payment calculations. 760.210 Section 760.210... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program § 760.210 Honeybee payment calculations. (a) An eligible honeybee producer may...
7 CFR 760.210 - Honeybee payment calculations.
Code of Federal Regulations, 2014 CFR
2014-01-01
... 7 Agriculture 7 2014-01-01 2014-01-01 false Honeybee payment calculations. 760.210 Section 760.210... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program § 760.210 Honeybee payment calculations. (a) An eligible honeybee producer may...
7 CFR 760.210 - Honeybee payment calculations.
Code of Federal Regulations, 2012 CFR
2012-01-01
... 7 Agriculture 7 2012-01-01 2012-01-01 false Honeybee payment calculations. 760.210 Section 760.210... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program § 760.210 Honeybee payment calculations. (a) An eligible honeybee producer may...
7 CFR 760.210 - Honeybee payment calculations.
Code of Federal Regulations, 2010 CFR
2010-01-01
... 7 Agriculture 7 2010-01-01 2010-01-01 false Honeybee payment calculations. 760.210 Section 760.210... AGRICULTURE SPECIAL PROGRAMS INDEMNITY PAYMENT PROGRAMS Emergency Assistance for Livestock, Honeybees, and Farm-Raised Fish Program § 760.210 Honeybee payment calculations. (a) An eligible honeybee producer may...
34 CFR Appendix B to Part 300 - Proportionate Share Calculation
Code of Federal Regulations, 2013 CFR
2013-07-01
... 34 Education 2 2013-07-01 2013-07-01 false Proportionate Share Calculation B Appendix B to Part... CHILDREN WITH DISABILITIES Pt. 300, App. B Appendix B to Part 300—Proportionate Share Calculation Each LEA... special education and related services under Part B, as compared with the total number of...
34 CFR Appendix B to Part 300 - Proportionate Share Calculation
Code of Federal Regulations, 2014 CFR
2014-07-01
... 34 Education 2 2014-07-01 2013-07-01 true Proportionate Share Calculation B Appendix B to Part 300... CHILDREN WITH DISABILITIES Pt. 300, App. B Appendix B to Part 300—Proportionate Share Calculation Each LEA... special education and related services under Part B, as compared with the total number of...
46 CFR 172.170 - Damage stability calculations.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 46 Shipping 7 2013-10-01 2013-10-01 false Damage stability calculations. 172.170 Section 172.170 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.170 Damage stability calculations. (a) Each tankship must be...
46 CFR 172.170 - Damage stability calculations.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 46 Shipping 7 2012-10-01 2012-10-01 false Damage stability calculations. 172.170 Section 172.170 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.170 Damage stability calculations. (a) Each tankship must be...
46 CFR 172.170 - Damage stability calculations.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 46 Shipping 7 2011-10-01 2011-10-01 false Damage stability calculations. 172.170 Section 172.170 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.170 Damage stability calculations. (a) Each tankship must be...
46 CFR 172.170 - Damage stability calculations.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 46 Shipping 7 2014-10-01 2014-10-01 false Damage stability calculations. 172.170 Section 172.170 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.170 Damage stability calculations. (a) Each tankship must be...
46 CFR 172.170 - Damage stability calculations.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 46 Shipping 7 2010-10-01 2010-10-01 false Damage stability calculations. 172.170 Section 172.170 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES... Under Subchapter O of This Chapter § 172.170 Damage stability calculations. (a) Each tankship must be...
34 CFR Appendix A to Part 300 - Excess Costs Calculation
Code of Federal Regulations, 2010 CFR
2010-07-01
... 34 Education 2 2010-07-01 2010-07-01 false Excess Costs Calculation A Appendix A to Part 300 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION... CHILDREN WITH DISABILITIES Pt. 300, App. A Appendix A to Part 300—Excess Costs Calculation Except...
Updated Coronal Equilibrium Calculations
NASA Astrophysics Data System (ADS)
Bryans, Paul; Badnell, N. R.; Gorczyca, T. W.; Laming, J. M.; Mitthumsiri, W.; Savin, D. W.
2006-06-01
Reliably interpreting solar spectra requires accurate ionization balance calculations. However, much of the atomic data needed for these calculations have not been generated using modern theoretical methods and are often highly suspect. This translates directly into the reliability of the collisional ionization equilibrium (CIE) calculations. We make use of state-of-the-art calculations of dielectronic recombination (DR) rate coefficients for the hydrogenic through Na-like ions of all elements from He through to Zn. We also make use of state-of-the-art radiative recombination (RR) rate coefficient calculations for the bar e through Na-like ions of all elements from H to Zn. Here we present improved CIE calculations for temperatures from 1e4 to 1e9 K using our data and the recommended electron impact ionization data of Mazzotta et al. (1998, A&AS, 133, 403) for elements up through Ni and Mazzotta (private communication) for Cu and Zn. DR and RR data for ionization stages that have not been updated are also taken from these two additional sources. We compare our calculated fractional ionic abundances using these data with those presented by Mazzotta et al. for all elements from H to Ni. The differences in peak fractional abundance are up to 60%. We also compare with the fractional ionic abundances for Mg, Si, S, Ar, Ca, Fe, and Ni derived from the modern DR calculations of Gu (2003a, ApJ, 590, 1131; 2004, ApJ, 153, 389) for the H-like through Na-like ions, and the RR calculations of Gu (2003b, ApJ, 589, 1085) for the bare through F-like ions. These results are in better agreement with our work, with differences in peak fractional abundance of less than 10%. This work was supported in part by the NASA Solar SR&T and LWS programs, theOffice of Naval Research, and PPARC.
Simpkins, Ali
1997-06-10
VENTSAR XL is an EXCEL Spreadsheet that can be used to calculate downwind doses as a result of a hypothetical atmospheric release. Both building effects and plume rise may be considered. VENTSAR XL will run using any version of Microsoft EXCEL version 4.0 or later. Macros (the programming language of EXCEL) was used to automate the calculations. The user enters a minimal amount of input and the code calculates the resulting concentrations and doses at various downwind distances as specified by the user.
Airborne antenna pattern calculations
NASA Technical Reports Server (NTRS)
Knerr, T. J.; Mielke, R. R.
1981-01-01
Progress on the development of modeling software, testing software against caclulated data from program VPAP and measured patterns, and calculating roll plane patterns for general aviation aircraft is reported. Major objectives are the continued development of computer software for aircraft modeling and use of this software and program OSUVOL to calculate principal plane and volumetric radiation patterns. The determination of proper placement of antennas on aircraft to meet the requirements of the Microwave Landing System is discussed. An overview of the performed work, and an example of a roll plane model for the Piper PA-31T Cheyenne aircraft and the resulting calculated roll plane radiation pattern are included.
NASA Astrophysics Data System (ADS)
Novotný, Jiří
2017-03-01
A theory known as special Galileon has recently attracted considerable interest due to its peculiar properties. It has been shown that it represents an extremal member of the set of effective field theories with an enhanced soft limit. This property makes its tree-level S -matrix fully on-shell reconstructible and representable by means of the Cachazo-He-Yuan representation. The enhanced soft limit is a consequence of new hidden symmetry of the special Galileon action; however, until now, the origin of this peculiar symmetry has remained unclear. In this paper we interpret this symmetry as a special transformation of the coset space GAL (D ,1 ) /S O (1 ,D -1 ) and show that there exists a three-parametric family of invariant Galileon actions. The latter family is closed under the duality which appears as a natural generalization of the above mentioned symmetry. We also present a geometric construction of the special Galileon action using a D -dimensional brane propagating in 2 D -dimensional flat pseudo-Riemannian space. Within such a framework, the special Galileon symmetry emerges as a U (1 ,D -1 ) symmetry of the target space, which can be treated as a D -dimensional Kähler manifold. Such a treatment allows for classification of the higher order invariant Lagrangians needed as counterterms on the quantum level. We also briefly comment on the relation between such higher order Lagrangians and the Lagrangians that are invariant with respect to the polynomial shift symmetry.
Magnetoresistive waves in plasmas
NASA Astrophysics Data System (ADS)
Felber, F. S.; Hunter, R. O., Jr.; Pereira, N. R.; Tajima, T.
1982-10-01
The self-generated magnetic field of a current diffusing into a plasma between conductors can magnetically insulate the plasma. Propagation of magnetoresistive waves in plasmas is analyzed. Applications to plasma opening switches are discussed.
Collisionless Coupling between Explosive Debris Plasma and Magnetized Ambient Plasma
NASA Astrophysics Data System (ADS)
Bondarenko, Anton
2016-10-01
The explosive expansion of a dense debris plasma cloud into relatively tenuous, magnetized, ambient plasma characterizes a wide variety of astrophysical and space phenomena, including supernova remnants, interplanetary coronal mass ejections, and ionospheric explosions. In these rarified environments, collective electromagnetic processes rather than Coulomb collisions typically mediate the transfer of momentum and energy from the debris plasma to the ambient plasma. In an effort to better understand the detailed physics of collisionless coupling mechanisms in a reproducible laboratory setting, the present research jointly utilizes the Large Plasma Device (LAPD) and the Phoenix laser facility at UCLA to study the super-Alfvénic, quasi-perpendicular expansion of laser-produced carbon (C) and hydrogen (H) debris plasma through preformed, magnetized helium (He) ambient plasma via a variety of diagnostics, including emission spectroscopy, wavelength-filtered imaging, and magnetic field induction probes. Large Doppler shifts detected in a He II ion spectral line directly indicate initial ambient ion acceleration transverse to both the debris plasma flow and the background magnetic field, indicative of a fundamental process known as Larmor coupling. Characterization of the laser-produced debris plasma via a radiation-hydrodynamics code permits an explicit calculation of the laminar electric field in the framework of a ``hybrid'' model (kinetic ions, charge-neutralizing massless fluid electrons), thus allowing for a simulation of the initial response of a distribution of He II test ions. A synthetic Doppler-shifted spectrum constructed from the simulated velocity distribution of the accelerated test ions excellently reproduces the spectroscopic measurements, confirming the role of Larmor coupling in the debris-ambient interaction.
National Stormwater Calculator
EPA’s National Stormwater Calculator (SWC) is a desktop application that estimates the annual amount of rainwater and frequency of runoff from a specific site anywhere in the United States (including Puerto Rico).
PHYSICOCHEMICAL PROPERTY CALCULATIONS
Computer models have been developed to estimate a wide range of physical-chemical properties from molecular structure. The SPARC modeling system approaches calculations as site specific reactions (pKa, hydrolysis, hydration) and `whole molecule' properties (vapor pressure, boilin...
PHYSICOCHEMICAL PROPERTY CALCULATIONS
Computer models have been developed to estimate a wide range of physical-chemical properties from molecular structure. The SPARC modeling system approaches calculations as site specific reactions (pKa, hydrolysis, hydration) and `whole molecule' properties (vapor pressure, boilin...
... Alcohol Calorie Calculator Find out the number of beer and hard alcohol calories you are consuming. Simply ... calories) Average Drinks Per Week Monthly Subtotal Calories Beer Regular 12 149 Regular Beer Light 12 110 ...
Interval arithmetic in calculations
NASA Astrophysics Data System (ADS)
Bairbekova, Gaziza; Mazakov, Talgat; Djomartova, Sholpan; Nugmanova, Salima
2016-10-01
Interval arithmetic is the mathematical structure, which for real intervals defines operations analogous to ordinary arithmetic ones. This field of mathematics is also called interval analysis or interval calculations. The given math model is convenient for investigating various applied objects: the quantities, the approximate values of which are known; the quantities obtained during calculations, the values of which are not exact because of rounding errors; random quantities. As a whole, the idea of interval calculations is the use of intervals as basic data objects. In this paper, we considered the definition of interval mathematics, investigated its properties, proved a theorem, and showed the efficiency of the new interval arithmetic. Besides, we briefly reviewed the works devoted to interval analysis and observed basic tendencies of development of integral analysis and interval calculations.
Stormwater Calculator (SWC) webinar
Jason Berner presents EPA’s National Stormwater Calculator developed to help support local, state and national stormwater management objectives and regulatory efforts to reduce runoff using green infrastructure practices as low impact development controls.
ERIC Educational Resources Information Center
Hiatt, Arthur A.
1987-01-01
Ten activities that give learners in grades 5-8 a chance to explore mathematics with calculators are provided. The activity cards involve such topics as odd addends, magic squares, strange projects, and conjecturing rules. (MNS)
Which is safer source plasma for manufacturing in China: apheresis plasma or recovered plasma?
Liu, Yu; Li, Changqing; Wang, Ya; Zhang, Yan; Wu, Binting; Ke, Ling; Xu, Min; Liu, Gui; Liu, Zhong
2016-05-01
In most countries, the plasma for derivative production includes two types of plasma, apheresis plasma (AP) and recovered plasma (RP). However, the plasma recovered from whole blood is not permitted for manufacture in China. Because of the lack of source plasma and the surplus of RP, the Chinese government is considering allowing RP as an equivalent source for the production of plasma derivatives. It is known that human blood can be contaminated by various infectious agents. The objective of the study was to evaluate if infectious risk would increase by enacting this policy. The samples from the two types of blood donors from January 1 to December 31, 2013, were collected. Supplementary testing was conducted and the residual risk (RR) of human immunodeficiency virus (HIV), hepatitis B virus, and hepatitis C virus (HCV) in the two types of blood donors and donations were calculated through the incidence-window period model. Prevalence of the markers of hepatitis E virus, hepatitis A virus, severe fever with thrombocytopenia syndrome bunyavirus, cytomegalovirus, B19, and West Nile virus was calculated. No significant difference was found in the RR of the three pathogens in the two types of blood donors. However, after the quarantine period, the RR of HCV and HIV in AP was significantly lower than that in RP. A quarantine period of 2 years will make the infectious risk of RP not significantly different than that of AP. Our data demonstrate that allowing RP to be used for the manufacture of plasma derivatives will not increase its infectious disease risk if coupled with a 2-year inventory hold. © 2016 AABB.
Electrostatic analysis of the tokamak edge plasma
Motley, R.W.
1981-07-01
The intrusion of an equipotential poloidal limiter into the edge plasma of a circular tokamak discharge distorts the axisymmetry in two ways: (1) it (partially) shorts out the top-to-bottom Pfirsch-Schlueter driving potentials, and (2) it creates zones of back current flow into the limiter. The resulting boundary mismatch between the outer layers and the inner axisymmetric Pfirsch-Schlueter layer provides free energy to drive the edge plasma unstable. Special limiters are proposed to symmetrize the edge plasma and thereby reduce the electrical and MHD activity in the boundary layer.
Evolutionary development of the space plasma laboratory
NASA Technical Reports Server (NTRS)
Roberts, W. T.
1984-01-01
In connection with payload definition studies for the Shuttle, one particular study, initiated in 1971, was concerned with the Definition of a Plasma Physics and Environmental Perturbation Laboratory (PPEPL). Possibilities were explored for performing, from a manned Shuttle-borne laboratory, investigations utilizing the natural space plasma environment around the Shuttle, and investigations employing controlled active experiments within the space plasma environment. Special emphasis was placed on employing controlled active experiment techniques using a manned Shuttle for short duration (7 to 30 days) missions and frequent reflights.
ECR Plasma Sterilisation, Argon and Nitrogen Treated Plasma
NASA Astrophysics Data System (ADS)
Helhel, Selcuk; Oksuz, Lutfi; Cerezci, Osman; Rad, Abbas Y.
2004-09-01
ECR type plasma system was built to produce plasma in axial direction. Plasma was initiated in a specially designed Nickel - Chrome cylindrical vacuum tube which is being driven through dielectric window by 2.45GHz commercial magnetron source. Tube is also surrounded by a coil driving 150ADC to generate approximately 875Gauss magnetic field at the center. Langmuir probe and ICCD for optical spectrometry were used to characterize internal parameters like electron density, electron temperature and different characteristics of the plasma. Bacillus Subtilis var nigar, bacillus Stearothermophilus, bacillus pumilus E601, Escherichia coli and staphylococcus aureus type bacteria were selected as a reference. Each is resistant for different actions while the Bacilus cereus is the most resistant bacteria for microwave interaction. This study presents the effect of system on used bacteria. Those are gram positive and gram negative bacteria that refers to structure of cell wall. The sterilization efficacy of Argon type ECR plasma was found to be over 99, 5% in Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis (vegetative cell), Bacillus cereus (vegetative cell), Bacillus pumilus and Escherichia coli. System response type is less than 2 minutes.
Electronic Broadening operator for relativistic plasmas
Meftah, M. T.; Naam, A.
2008-10-22
In this work we review some aspects of the semiclassical dipole impact approximation for isolated ion lines in relativistic plasma. Mainly we focuss our work on the collision operator for relativistic electrons. In this case, the electron trajectory around a positive charge in the plasma differs drastically from those known earlier as hyperbolic. The effect of this difference on the collision operator is discussed with respect the various plasma conditions. Some theoretical and practical aspects of lines -shape calculations are discussed. Detailed calculations are performed for the collision operator in the semiclassical (dipole) impact approximation.
NASA Technical Reports Server (NTRS)
Bauschlicher, Charles W.; Arnold, James O. (Technical Monitor)
1997-01-01
The current methods of quantum chemical calculations will be reviewed. The accent will be on the accuracy that can be achieved with these methods. The basis set requirements and computer resources for the various methods will be discussed. The utility of the methods will be illustrated with some examples, which include the calculation of accurate bond energies for SiF$_n$ and SiF$_n^+$ and the modeling of chemical data storage.
Systematics and limit calculations
Fisher, Wade; /Fermilab
2006-12-01
This note discusses the estimation of systematic uncertainties and their incorporation into upper limit calculations. Two different approaches to reducing systematics and their degrading impact on upper limits are introduced. An improved {chi}{sup 2} function is defined which is useful in comparing Poisson distributed data with models marginalized by systematic uncertainties. Also, a technique using profile likelihoods is introduced which provides a means of constraining the degrading impact of systematic uncertainties on limit calculations.
Source and replica calculations
Whalen, P.P.
1994-02-01
The starting point of the Hiroshima-Nagasaki Dose Reevaluation Program is the energy and directional distributions of the prompt neutron and gamma-ray radiation emitted from the exploding bombs. A brief introduction to the neutron source calculations is presented. The development of our current understanding of the source problem is outlined. It is recommended that adjoint calculations be used to modify source spectra to resolve the neutron discrepancy problem.