Finite Larmor radius flute mode theory with end loss
International Nuclear Information System (INIS)
Kotelnikov, I.A.; Berk, H.L.
1993-08-01
The theory of flute mode stability is developed for a two-energy- component plasma partially terminated by a conducting limiter. The formalism is developed as a preliminary study of the effect of end-loss in open-ended mirror machines where large Larmor radius effects are important
Finite-Larmor-radius stability theory of EBT plasmas
International Nuclear Information System (INIS)
Berk, H.L.; Cheng, C.Z.; Rosenbluth, M.N.; Van Dam, J.W.
1982-11-01
An eikonal ballooning-mode formalism is developed to describe curvature-driven modes of hot electron plasmas in bumpy tori. The formalism treats frequencies comparable to the ion-cyclotron frequency, as well as arbitrary finite Larmor radius and field polarization, although the detailed analysis is restricted to E/sub parallel/ = 0. Moderate hot-electron finite-Larmor-radius effects are found to lower the background beta core limit, whereas strong finite-Lamor-radius effects produce stabilization
Effect of limiter end loss in finite Larmor radius theory
International Nuclear Information System (INIS)
Berk, H.L.; Kotelnikov, I.A.
1993-08-01
We have examined the effect of incomplete line tying on the MHD flute mode with FLR (finite Larmor radius) effects. We show that the combination of line tying and FLR effects can slow down MHD instability, but cannot produce complete stabilization
Finite Larmor radius stabilization of ballooning modes in tokamaks
International Nuclear Information System (INIS)
Tsang, K.T.
1980-07-01
A ballooning mode equation that includes full finite Larmor radius effects has been derived from the Vlasov equation for a circular tokamak equilibrium. Numerical solution of this equation shows that finite Larmor radius effects are stabilizing
Experimental study of finite Larmor radius effects
International Nuclear Information System (INIS)
Struve, K.W.
1980-08-01
Linear Z-pinches in Ar, Kr, Xe, N 2 , and He are experimentally studied in regimes where strong finite Larmor radius effects could provide a significant stabilizing effect. Scaling arguments show that for deuterium such a pinch has an electron line density of order 2 x 10 15 /cm. For higher Z plasmas a higher line density is allowed, the exact value of which depends on the average ion charge. The pinch is formed by puffing gas axially through the cathode towards the anode of an evacuated pinch chamber. When the gas reaches the anode, the pinch bank is fired. The pinch current rises in 2 to 3 μsec to a maximum of 100 to 200 kA. The pinch bank capacitance is 900 μF, and the external inductance is 100 nH. Additionally, the bank is fused to increase dI/dt. The primary diagnostics are a framing camera, a spatially resolved Mach-Zehnder interferometer, and X-ray absorption
Effect of Hall Current and Finite Larmor Radius Corrections on ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Astrophysics and Astronomy; Volume 37; Issue 3. Effect of Hall Current and Finite Larmor Radius Corrections on Thermal Instability of Radiative Plasma for Star Formation in Interstellar Medium (ISM). Sachin Kaothekar. Research Article Volume 37 Issue 3 September 2016 Article ID 23 ...
On finite larmor radius stabilization of Z-pinches
International Nuclear Information System (INIS)
Hellsten, T.
1982-12-01
Finite Larmor radius stabilization of Z-pinches is discussed. Stability criteria can be derived for a class of equilibria having constant mass and current density. The internal modes can be stabilized provided the line density not exceed a critical value of the order of 10 18 ions/m. (Author)
Finite-Larmor-radius effects on z-pinch stability
Scheffel, Jan; Faghihi, Mostafa
1989-06-01
The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. We use the incompressible FLR MHD model; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2r dp/dr + m2B2/μ0 ≥ 0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the FLR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but not absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the crosssection for wavelengths λ/a ≤ 1, where a denotes the pinch radius. As a general z-pinch result a critical line-density limit Nmax = 5 × 1018 m-1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 1020 m-1.
Finite-Larmor-radius effects on z-pinch stability
Energy Technology Data Exchange (ETDEWEB)
Scheffel, J.; Faghihi, M. (Royal Inst. of Tech., Stockholm (Sweden))
1989-06-01
The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. The incompressible FLR MHD model is used; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2rdp/dr+m{sup 2}B{sup 2}/{mu}{sub 0}{ge}0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the LFR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but no absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the cross-section for wavelengths {lambda}/{alpha}{le}1, where {alpha} denotes the pinch radius. As a general z-pinch result a critical line-density limit ''N''{sub max}=5x10{sup 18}m{sup -1} is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10{sup 20} m{sup -1}. (author).
Finite-Larmor-radius effects on z-pinch stability
International Nuclear Information System (INIS)
Scheffel, J.; Faghihi, M.
1989-01-01
The effect of finite Larmor radius (FLR) on the stability of m = 1 small-axial-wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. The incompressible FLR MHD model is used; a collisionless fluid model that consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD, 2rdp/dr+m 2 B 2 /μ 0 ≥0 predicts instability for internal modes unless the current density is singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the LFR terms are included, a normal-mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall term has a damping (but no absolutely stabilizing) effect - in agreement with earlier work. On specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m = 1 modes are then fully stabilized over the cross-section for wavelengths λ/α≤1, where α denotes the pinch radius. As a general z-pinch result a critical line-density limit ''N'' max =5x10 18 m -1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. This limit corresponds to about five Larmor radii along the pinch radius. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10 20 m -1 . (author)
Finite Larmor radius effects on Z-pinch stability
International Nuclear Information System (INIS)
Scheffel, J.; Faghihi, M.
1987-10-01
The effect of finite Larmor radius (FLR) on the stability of m=1 small axial wavelength kinks in a z-pinch with purely poloidal magnetic field is investigated. We use the Incompressible FLR MHD model; a collisionless fluid model which consistently includes the relevant FLR terms due to ion gyroviscosity, Hall effect and electron diamagnetism. With FLR terms absent, the Kadomtsev criterion of ideal MHD 2rdp/dr+m 2 B 2 /μ 0 >=0 predicts instability for internal modes unless the current density becomes singular at the centre of the pinch. The same result is obtained in the present model, with FLR terms absent. When the FLR terms are included, a normal mode analysis of the linearized equations yields the following results. Marginally unstable (ideal) modes are stabilized by gyroviscosity. The Hall terms have a damping, however not stabilizing, effect, in agreement with earlier work. Specifying a constant current and particle density equilibrium, the effect of electron diamagnetism vanishes. For a z-pinch with parameters relevant to the EXTRAP experiment, the m=1 modes are then fully stabilized over the cross-section for wavelengths λ/a max =3-5x10 18 m -1 is found, above which gyroviscous stabilization near the plasma boundary becomes insufficient. The result holds for wavelengths close to, or smaller than, the pinch radius and for realistic equilibrium profiles. This limit is far below the required limit for a reactor with contained alpha particles, which is in excess of 10 20 m -1 . (authors)
Wave propagation near cyclotron resonance in the presence of large Larmor radius particles
International Nuclear Information System (INIS)
Cairns, R.A.; Lashmore-Davies, C.N.; Holt, H.; McDonald, D.C.
1995-02-01
Absorption of waves propagating across an inhomogeneous magnetic field is of crucial importance for cyclotron resonance heating. When the Larmor radius of the resonant particles is small compared to the wavelength, then the propagation can be described by differential equations. These have been derived by a considerable number of authors, but a comparatively simple method of obtaining them has recently been given by Cairns et al [Phys. Fluids B3, 2953 (1991)] and, for the relativistic case which is relevant to electron cyclotron heating, by McDonald et al [Phys. Plasmas 1, 842 (1994)]. In a fusion plasma there may be a significant number of hot ions for which the Larmor radius is comparable to or larger than the perpendicular wavelength. It is important to be able to calculate the effect of these ions on ion cyclotron phenomena. In this case the system is described by integro-differential equations, the structure of which is essentially determined by the fact that the response at a given position is determined by the wave amplitude over a region whose width is of the order of a Larmor radius. The equations describing this situation have been obtained by Sauter and Vaclavik [Theory of Fusion Plasmas, Editrice Compositori, Bologna (1990) p. 403] and by Brambilla [Plasma Physics and Controlled Fusion 33, 1029 (1991)]. Here we show how the simplified method referred to above can be adapted to this case and used to find various alternative forms for the equations. (author)
Low beta rigid mode stability criterion for an arbitrary Larmor radius plasma
International Nuclear Information System (INIS)
Berk, H.L.; Wong, H.V.
1987-05-01
The low beta flute interchange dispersion relation for rigid displacement perturbation of axisymmetric plasma equilibria with arbitrary Larmor radius particles and field line curvature, large compared to the plasma radius, is derived. The equilibrium particle orbits are characterized by two constants of motion, energy and angular momentum, and a third adiabatic invariant derived from the rapid radial motion. The Vlasov equation is integrated, assuming that the mode frequency, axial ''bounce'' frequency, and particle drift frequency are small compared to the cyclotron frequency, and it is demonstrated that the plasma response to a rigid perturbation has a universal character independent of Larmor radius. As a result the interchange instability is the same as that predicted from conventional MHD theory. However, a new prediction, more optimistic than earlier work, is found for the low density threshold of systems like Migma, which are disc-shaped, that is, the axial extent Δz is less than the radial extent r 0 . For Δz/sub r 0 / much less than 1, the stability criterion is determined by the total particle number. Whereas the older theory (Δz/sub r 0 / much greater than 1) predicted instability at about the densities achieved in actual Migma experiments, the present theory (Δz/sub r 0 / much less than 1) indicates that the experimental results were for plasmas with particle number below the interchange threshold
International Nuclear Information System (INIS)
Jain, Shweta; Sharma, Prerana; Chhajlani, R. K.
2015-01-01
The Jeans instability of self-gravitating quantum plasma is examined considering the effects of viscosity, finite Larmor radius (FLR) corrections and rotation. The analysis is done by normal mode analysis theory with the help of relevant linearized perturbation equations of the problem. The general dispersion relation is obtained using the quantum magneto hydrodynamic model. The modified condition of Jeans instability is obtained and the numerical calculations have been performed to show the effects of various parameters on the growth rate of Jeans instability
Interchange instability with line-typing and finite Larmor radius effects
International Nuclear Information System (INIS)
Riordan, J.C.; Hartman, C.W.
1977-01-01
Finite Larmor radius and end effects are included in a treatment of the low-β interchange instability. Higher order modes are shown to be destabilized by incomplete line-tying through an external plasma
Transition to chaos for ballooning modes stabilized by finite Larmor radius effects
Energy Technology Data Exchange (ETDEWEB)
Weiland, J; Wilhelmsson, H [Chalmers Tekniska Hoegskola, Goeteborg (Sweden). Institutionen foer Elektromagnetisk Faeltteori
1983-08-01
The nonlinear dynamics of interacting ballooning modes, stabilized by finite Larmor radius effects is analyzed in terms of a set of equations, which exhibit stochastic properties. These are explicitly shown to depend on the balance between shear and driving pressure force. The onset of bifurcations and chaotic behaviour are directly identified with certain values of parameters characterizing the physical system.
Effect of Hall Current and Finite Larmor Radius Corrections on ...
Indian Academy of Sciences (India)
clumpy interstellar medium, globular clusters and galaxy formation, and many ... plasma taking radiative cooling function and two-fluid theory into account. .... Suffix '0' represents the initial equilibrium state, which is independent of space and.
The influence of finite Larmor radius effects on the radial interchange motions of plasma filaments
DEFF Research Database (Denmark)
Madsen, Jens; Garcia, Odd E.; Larsen, Jeppe Stærk
2011-01-01
The influence of finite Larmor radius (FLR) effects on the perpendicular convection of isolated particle density filaments driven by interchange motions in magnetized plasmas is investigated using a two-moment gyrofluid model. By means of numerical simulations on a two-dimensional, bi-periodic do......The influence of finite Larmor radius (FLR) effects on the perpendicular convection of isolated particle density filaments driven by interchange motions in magnetized plasmas is investigated using a two-moment gyrofluid model. By means of numerical simulations on a two-dimensional, bi......-periodic domain perpendicular to the magnetic field, it is demonstrated that the radial velocities of the blob-like filaments are roughly described by the inertial scaling, which prescribes a velocity proportional to the square root of the summed electron and ion pressures times the square root of the blob width...
Finite Larmor radius effects on the stability properties of internal modes of a z-pinch
International Nuclear Information System (INIS)
Aakerstedt, H.O.
1987-01-01
From the Vlasov-fluid model a set of approximate stability equations describing the stability of a cylindrically symmetric z-pinch is derived. The equations are derived in the limit of small gyroradius and include first order kinetic effects such as finite ion Larmor radius effects and resonant ion effects. Neglecting the resonant ion terms, we explicitly solve this set of equations for a constant current density profile leading to a dispersion relation. FLR effects are shown for the case of m=1 internal mode to be stabilizing and for large wavenumbers k, using a trial function approach, absolute stabilization is found. (author)
Fiber Z-pinch experiments and calculations in the finite Larmor radius regime
International Nuclear Information System (INIS)
Haines, M.G.; Dangor, A.E.; Coppins, M.
1996-01-01
The dense Z-pinch project at Imperial College is aimed at achieving radiative collapse to high density in a hydrogen plasma, and also to study plasmas close to controlled fusion conditions. To this end, the MAGPIE generator (2.4 MV, 1.25 Ω, and 200 ns) has been built and tested, and is now giving preliminary experimental data at 60% of full voltage for carbon and CD 2 fibers. These discharges are characterized by an initial radial expansion followed by the occurrence of m = 0 structures with transient X-ray emission from bright spots. Late in the discharge a disruption can occur, accompanied by hard X-ray emission from the anode due to an energetic electron beam and, in the case of CD 2 fibers, a neutron burst. Concomitant theoretical studies have solved the linear stability problem for a Z-pinch with large ion Larmor radii, showing that a reduction in growth rate of m = 0 and m = 1 modes to about 20% of the magnetohydrodynamic (MHD) value can occur for a parabolic density profile when the Larmor radius is optimally 20% of the pinch radius. Two-dimensional MHD simulations of Z-pinches in two extremes of focussed short-pulse laser-plasma interactions and of galactic jets reveal a nonlinear stabilizing effect in the presence of sheared flow. One-dimensional simulations show that at low line density the lower hybrid drift instability can lead to coronal radial expansion of a Z-pinch plasma. (Author)
DEFF Research Database (Denmark)
Held, Magnus; Wiesenberger, M.; Madsen, Jens
2016-01-01
Thermal effects on the perpendicular convection of seeded pressure blobs in the scrape-off layer of magnetised fusion plasmas are investigated. Our numerical study is based on a four field full-F gyrofluid model, which entails the consistent description of high fluctuation amplitudes and dynamic...... finite Larmor radius effects. We find that the maximal radial blob velocity increases with the square root of the initial pressure perturbation and that a finite Larmor radius contributes to highly compact blob structures that propagate in the poloidal direction. An extensive parameter study reveals...... that a smooth transition to this compact blob regime occurs when the finite Larmor radius effect strength, defined by the ratio of the magnetic field aligned component of the ion diamagnetic to the E × B vorticity, exceeds unity. The maximal radial blob velocities agree excellently with the inertial velocity...
Klein, R.; Gravier, E.; Morel, P.; Besse, N.; Bertrand, P.
2009-08-01
Describing turbulent transport in fusion plasmas is a major concern in magnetic confinement fusion. It is now widely known that kinetic and fluid descriptions can lead to significantly different properties. Although more accurate, the kinetic calculation of turbulent transport is much more demanding of computer resources than fluid simulations. An alternative approach is based on a water-bag representation of the distribution function that is not an approximation but rather a special class of initial conditions, allowing one to reduce the full kinetic Vlasov equation into a set of hydrodynamics equations while keeping its kinetic character [P. Morel, E. Gravier, N. Besse et al., Phys. Plasmas 14, 112109 (2007)]. In this paper, the water-bag concept is used in a gyrokinetic context to study finite Larmor radius effects with the possibility of using the full Larmor radius distribution instead of an averaged Larmor radius. The resulting model is used to study the ion temperature gradient (ITG) instability.
International Nuclear Information System (INIS)
Kotschenreuther, M.
1985-07-01
The dynamics of ideal and kinetic ballooning modes are considered analytically including parallel ion dynamics, but without electron dissipation. For ideal modes, parallel dynamics predominantly determine the growth rate when β is within approx.30% of the ideal threshold, resulting in a substantial reduction in growth rate. Compressibility also eliminates the stabilization effects of finite Larmor radius (FLR); FLR effects (when temperature gradients are neglected) can even increase the growth rate above the MHD value. Temperature gradients accentuate this by adding a new source of free energy independent of the MHD drive, in this region of ballooning coordinate corresponding in MHD to the continuum. Analytic dispersion relations are derived demonstrating the effects above; the formalism emphasizes the similarities between the ideal MHD and kinetic cases
International Nuclear Information System (INIS)
Damiano, P. A.; Wright, A. N.; McKenzie, J. F.
2009-01-01
The linear wave equation (sixth order in space and time) and the corresponding dispersion relation is derived for Hall magnetohydrodynamic (MHD) waves including electron inertial and finite Larmor radius effects together with several limiting cases for a homogeneous plasma. We contrast these limits with the solution of the full dispersion relation in terms of wave normal (k perpendicular ,k || ) diagrams to clearly illustrate the range of applicability of the individual approximations. We analyze the solutions in terms of all three MHD wave modes (fast, slow, and Alfven), with particular attention given to how the Alfven branch (including the cold ideal field line resonance (FLR) [D. J. Southwood, Planet. Space Sci. 22, 483 (1974)]) is modified by the Hall term and electron inertial and finite Larmor radius effects. The inclusion of these terms breaks the degeneracy of the Alfven branch in the cold plasma limit and displaces the asymptote position for the FLR to a line defined by the electron thermal speed rather than the Alfven speed. For a driven system, the break in this degeneracy implies that a resonance would form at one field line for small k perpendicular and then shift to another as k perpendicular →∞. However for very large ωk perpendicular /V A , Hall term effects lead to a coupling to the whistler mode, which would then transport energy away from the resonant layer. The inclusion of the Hall term also significantly effects the characteristics of the slow mode. This analysis reveals an interesting 'swapping' of the perpendicular root behavior between the slow and Alfven branches.
Sotnikov, V. I.; Kim, T. C.; Mishin, E. V.; Kil, H.; Kwak, Y. S.; Paraschiv, I.
2017-12-01
Ionospheric irregularities cause scintillations of electromagnetic signals that can severely affect navigation and transionospheric communication, in particular during space storms. At mid-latitudes the source of F-region Field Aligned Irregularities (FAI) is yet to be determined. They can be created in enhanced subauroral flow channels (SAI/SUBS), where strong gradients of electric field, density and plasma temperature are present. Another important source of FAI is connected with Medium-scale travelling ionospheric disturbances (MSTIDs). Related shear flows and plasma density troughs point to interchange and Kelvin-Helmholtz type instabilities as a possible source of plasma irregularities. A model of nonlinear development of these instabilities based on the two-fluid hydrodynamic description with inclusion of finite Larmor radius effects will be presented. This approach allows to resolve density irregularities on the meter scale. A numerical code in C language to solve the derived nonlinear equations for analysis of interchange and flow velocity shear instabilities in the ionosphere was developed. This code will be used to analyze competition between interchange and Kelvin-Helmholtz instabilities in the mid-latitude region. The high-resolution simulations with continuous density and velocity profiles will be driven by the ambient conditions corresponding to the in situ data obtained during the 2016 Daejeon (Korea) and MU (Japan) radar campaign and data collected simultaneously by the Swarm satellites passed over Korea and Japan. PA approved #: 88ABW-2017-3641
Kinetic-Scale Magnetic Turbulence and Finite Larmor Radius Effects at Mercury
Uritsky, V. M.; Slavin, J. A.; Khazanov, G. V.; Donovan, E. F.; Boardsen, S. A.; Anderson, B. J.; Korth, H.
2011-01-01
We use a nonstationary generalization of the higher-order structure function technique to investigate statistical properties of the magnetic field fluctuations recorded by MESSENGER spacecraft during its first flyby (01/14/2008) through the near-Mercury space environment, with the emphasis on key boundary regions participating in the solar wind - magnetosphere interaction. Our analysis shows, for the first time, that kinetic-scale fluctuations play a significant role in the Mercury's magnetosphere up to the largest resolvable timescale (approx.20 s) imposed by the signal nonstationariry, suggesting that turbulence at this plane I is largely controlled by finite Larmor radius effects. In particular, we report the presence of a highly turbulent and extended foreshock system filled with packets of ULF oscillations, broad-band intermittent fluctuations in the magnetosheath, ion-kinetic turbulence in the central plasma sheet of Mercury's magnetotail, and kinetic-scale fluctuations in the inner current sheet encountered at the outbound (dawn-side) magnetopause. Overall, our measurements indicate that the Hermean magnetosphere, as well as the surrounding region, are strongly affected by non-MHD effects introduced by finite sizes of cyclotron orbits of the constituting ion species. Physical mechanisms of these effects and their potentially critical impact on the structure and dynamics of Mercury's magnetic field remain to be understood.
Energy Technology Data Exchange (ETDEWEB)
Kaothekar, Sachin, E-mail: sackaothekar@gmail.com [Department of Physics, Mahakal Institute of Technology, Ujjain-456664, Madhya Pradesh (India)
2016-08-15
I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR) corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM). A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.
Directory of Open Access Journals (Sweden)
Sachin Kaothekar
2016-08-01
Full Text Available I have studied the effects of finite electron inertia, finite ion Larmor radius (FLR corrections, and radiative heat-loss function on the thermal instability of an infinite homogeneous, viscous plasma incorporating the effect of thermal conductivity for star formation in interstellar medium (ISM. A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation is discussed for longitudinal and transverse directions to the external magnetic field and the conditions of modified thermal instabilities and stabilities are discussed in different cases. We find that the thermal instability criterion is get modified into radiative instability criterion by inclusion of radiative heat-loss functions with thermal conductivity. The viscosity of medium removes the effect of FLR corrections from the condition of radiative instability. Numerical calculation shows stabilizing effect of heat-loss function, viscosity and FLR corrections, and destabilizing effect of finite electron inertia on the thermal instability. Results carried out in this paper shows that stars are formed in interstellar medium mainly due to thermal instability.
First-order finite-Larmor-radius fluid modeling of tearing and relaxation in a plasma pinch
Energy Technology Data Exchange (ETDEWEB)
King, J. R. [Department of Physics, University of Wisconsin-Madison, 1150 University Ave., Madison, Wisconsin 53706 (United States); Tech-X Corporation, 5621 Arapahoe Ave., Suite A Boulder, Colorado 80303 (United States); Sovinec, C. R. [Department of Engineering-Physics, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Mirnov, V. V. [Department of Physics, University of Wisconsin-Madison, 1150 University Ave., Madison, Wisconsin 53706 (United States)
2012-05-15
Drift and Hall effects on magnetic tearing, island evolution, and relaxation in pinch configurations are investigated using a non-reduced first-order finite-Larmor-radius (FLR) fluid model with the nonideal magnetohydrodynamics (MHD) with rotation, open discussion (NIMROD) code [C.R. Sovinec and J. R. King, J. Comput. Phys. 229, 5803 (2010)]. An unexpected result with a uniform pressure profile is a drift effect that reduces the growth rate when the ion sound gyroradius ({rho}{sub s}) is smaller than the tearing-layer width. This drift is present only with warm-ion FLR modeling, and analytics show that it arises from {nabla}B and poloidal curvature represented in the Braginskii gyroviscous stress. Nonlinear single-helicity computations with experimentally relevant {rho}{sub s} values show that the warm-ion gyroviscous effects reduce saturated-island widths. Computations with multiple nonlinearly interacting tearing fluctuations find that m = 1 core-resonant-fluctuation amplitudes are reduced by a factor of two relative to single-fluid modeling by the warm-ion effects. These reduced core-resonant-fluctuation amplitudes compare favorably to edge coil measurements in the Madison Symmetric Torus (MST) reversed-field pinch [R. N. Dexter et al., Fusion Technol. 19, 131 (1991)]. The computations demonstrate that fluctuations induce both MHD- and Hall-dynamo emfs during relaxation events. The presence of a Hall-dynamo emf implies a fluctuation-induced Maxwell stress, and the simulation results show net transport of parallel momentum. The computed magnitude of force densities from the Maxwell and competing Reynolds stresses, and changes in the parallel flow profile, are qualitatively and semi-quantitatively similar to measurements during relaxation in MST.
Energy Technology Data Exchange (ETDEWEB)
Jain, Shweta; Sharma, Prerana [Physics Department, Ujjain Engineering College, Ujjain, MP-456010 (India); Kaothekar, Sachin [Physics Department, Mahakal Institute of Technology, Ujjain, MP-456664 (India); Chhajlani, R. K., E-mail: sackaothekar@gmail.com [Retired, School of Studies in Physics, Vikram University Ujjain, MP-456010 (India)
2016-10-01
The thermal instability of an infinite homogeneous, thermally conducting, and rotating plasma, incorporating finite electrical resistivity, finite electron inertia, and an arbitrary radiative heat-loss function in the presence of finite Larmor radius corrections and Hall current, has been studied. Analysis has been made with the help of linearized magnetohydrodynamics (MHD) equations. A general dispersion relation is obtained using the normal mode analysis method, and the dispersion relation is discussed for longitudinal propagation and transverse propagation separately. The dispersion relation has been solved numerically to obtain the dependence of the growth rate on the various parameters involved. The conditions of modified thermal instability and stability are discussed in the different cases of interest.
Yamagishi, Osamu
2018-04-01
Radial wavenumber dependencies of the residual zonal potential for E × B flow in a circular, large aspect ratio tokamak is investigated by means of the collisionless gyrokinetic simulations of Rosenbluth-Hinton (RH) test and the semi-analytic approach using an analytic solution of the gyrokinetic equation Rosenbluth and Hinton (1998 Phys. Rev. Lett. 80 724). By increasing the radial wavenumber from an ion Larmor radius scale {k}r{ρ }i≲ 1 to an electron Larmor radius scale {k}r{ρ }e≲ 1, the well-known level ˜ O[1/(1+1.6{q}2/\\sqrt{r/{R}0})] is retained, while the level remains O(1) when the wavenumber is decreased from the electron to the ion Larmor radius scale, if physically same adiabatic assumption is presumed for species other than the main species that is treated kinetically. The conclusion is not modified by treating both species kinetically, so that in the intermediate scale between the ion and electron Larmor radius scale it seems difficult to determine the level uniquely. The toroidal momentum conservation property in the RH test is also investigated by including an initial parallel flow in addition to the perpendicular flow. It is shown that by taking a balance between the initial parallel flow and perpendicular flows which include both E × B flow and diamagnetic flow in the initial condition, the mechanical toroidal angular momentum is approximately conserved despite the toroidal symmetry breaking due to the finite radial wavenumber zonal modes. Effect of electromagnetic potentials is also investigated. When the electromagnetic potentials are applied initially, fast oscillations which are faster than the geodesic acoustic modes are introduced in the decay phase of the zonal modes. Although the residual level in the long time limit is not modified, this can make the time required to reach the stationary zonal flows longer and may weaken the effectiveness of the turbulent transport suppression by the zonal flows.
International Nuclear Information System (INIS)
Goto, R.; Hatori, T.; Miura, H.; Ito, A.; Sato, M.
2015-01-01
Two-fluid and the finite Larmor effects on linear and nonlinear growth of the Rayleigh-Taylor instability in a two-dimensional slab are studied numerically with special attention to high-wave-number dynamics and nonlinear structure formation at a low β-value. The two effects stabilize the unstable high wave number modes for a certain range of the β-value. In nonlinear simulations, the absence of the high wave number modes in the linear stage leads to the formation of the density field structure much larger than that in the single-fluid magnetohydrodynamic simulation, together with a sharp density gradient as well as a large velocity difference. The formation of the sharp velocity difference leads to a subsequent Kelvin-Helmholtz-type instability only when both the two-fluid and finite Larmor radius terms are incorporated, whereas it is not observed otherwise. It is shown that the emergence of the secondary instability can modify the outline of the turbulent structures associated with the primary Rayleigh-Taylor instability
Energy Technology Data Exchange (ETDEWEB)
Kudaka, Shoju [Department of Physics, University of the Ryukyus, Okinawa 903-0129 (Japan); Matsumoto, Shuichi, E-mail: shuichi@edu.u-ryukyu.ac.jp [Department of Mathematics, University of the Ryukyus, Okinawa 903-0129 (Japan)
2012-10-01
The idea of a Larmor clock is reexamined in the relativistic regime. We propose a concept of proper time for quantum theoretical particles. The Larmor clock can measure, under some relevant conditions, the proper time that passes while the particle stays in a space region. Our approach to Larmor clock is different than those of other researchers in the following two aspects: our concept of Larmor clock does not distinguish whether the particle is transmitted or reflected at the end of its stay, and pointer of our Larmor clock is not the spin but the total angular momentum. -- Highlights: ► The idea of a Larmor clock is reexamined in the relativistic regime. ► We propose a concept of proper time for quantum theoretical particles. ► The Larmor clock measures the passage of this quantum theoretical proper time.
Larmor precession reflectometry
International Nuclear Information System (INIS)
Lauter, H.J.; Toperverg, B.P.; Lauter-Pasyuk, V.; Petrenko, A.; Aksenov, V.
2004-01-01
Larmor precession phase encoding is applied to modulate TOF reflection spectra measured from a polymer multilayer and from an Fe/Cr multilayer. It is proposed that decoding of the spectra can be used to extract the small-angle scattering signal from the polymer film-embedded nanoparticles. The second example is directed to demonstrate one of the plausible realizations of the vector polarization analysis in reflectometry of magnetic systems. This would allow to unambiguously reconstruct the transverse and lateral distribution of the magnetization vectors throughout the multilayered superlattices
Kinetic theory of plasma adiabatic major radius compression in tokamaks
International Nuclear Information System (INIS)
Gorelenkova, M.V.; Gorelenkov, N.N.; Azizov, E.A.; Romannikov, A.N.; Herrmann, H.W.
1998-01-01
In order to understand the individual charged particle behavior as well as plasma macroparameters (temperature, density, etc.) during the adiabatic major radius compression (R-compression) in a tokamak, a kinetic approach is used. The perpendicular electric field from the Ohm close-quote s law at zero resistivity is made use of in order to describe particle motion during the R-compression. Expressions for both passing and trapped particle energy and pitch angle change are derived for a plasma with high aspect ratio and circular magnetic surfaces. The particle behavior near the passing trapped boundary during the compression is studied to simulate the compression-induced collisional losses of alpha particles. Qualitative agreement is obtained with the alphas loss measurements in deuterium-tritium (D-T) experiments in the Tokamak Fusion Test Reactor (TFTR) [World Survey of Activities in Controlled Fusion Research [Nucl. Fusion special supplement (1991)] (International Atomic Energy Agency, Vienna, 1991)]. The plasma macroparameters evolution at the R-compression is calculated by solving the gyroaveraged drift kinetic equation. copyright 1998 American Institute of Physics
International Nuclear Information System (INIS)
Ghendrih, P.
1986-10-01
We expand the distribution functions on a basis of Hermite functions and obtain a general scheme to compute the local transport coefficients. The magnetic field dependence due to finite Larmor radius effects during the collision process is taken into account
The Lamb shift in muonic hydrogen and the proton radius from effective field theories
Energy Technology Data Exchange (ETDEWEB)
Peset, Clara; Pineda, Antonio [Universitat Autonoma de Barcelona, Grup de Fisica Teorica, Dept. Fisica and IFAE, Bellaterra (Barcelona) (Spain)
2015-12-15
We comprehensively analyse the theoretical prediction for the Lamb shift in muonic hydrogen, and the associated determination of the proton radius. We use effective field theories. This allows us to relate the proton radius with well-defined objects in quantum field theory, eliminating unnecessary model dependence. The use of effective field theories also helps us to organize the computation so that we can clearly state the parametric accuracy of the result. In this paper we review all (and check several of) the contributions to the energy shift of order α{sup 5}, as well as those that scale like α{sup 6} x logarithms in the context of non-relativistic effective field theories of QED. (orig.)
Larmor-precession based neutron scattering instrumentation
International Nuclear Information System (INIS)
Ioffe, Alexander
2009-01-01
The Larmor precession of the neutron spin in a magnetic field allows the attachment of a Larmor clock to every neutron. Such Larmor labelling opens the possibility for the development of unusual neutron scattering techniques, where the energy (momentum) resolution does not require the initial and final states to be well selected. This principally allows for achievement of very high energy (momentum) resolution that is not feasible at all with conventional neutron scattering techniques, because the required neutron beam monochromatization (collimation) will result in intolerable intensity losses. Such decoupling of resolution and collimation allows, for example, for a significant increase in the luminosity of small-angle scattering or high-resolution diffractometers; the fact that opens new perspectives for their implementation at middle flux neutron sources. Different kinds of Larmor clock-based instrumentation, particularly two alternative NSE techniques using rotating and time-gradient magnetic field arrangements, which can be considered as inexpensive and affordable alternatives to present day NSE techniques, will be discussed and results of simulations and first experiments will be presented. (author)
Larmor labeling by time-gradient magnetic fields
International Nuclear Information System (INIS)
Ioffe, Alexander; Bodnarchuk, Victor; Bussmann, Klaus; Mueller, Robert
2007-01-01
The Larmor labeling of neutrons, due to the Larmor precession of neutron spin in a magnetic field, opens the unique possibility for the development of neutron spin-echo (NSE) based on neutron scattering techniques, featuring an extremely high energy (momentum) resolution. Here, we present the experimental proof of a new method of the Larmor labeling using time-gradient magnetic fields
Neutron Larmor diffraction measurements for materials science
International Nuclear Information System (INIS)
Repper, J.; Keller, T.; Hofmann, M.; Krempaszky, C.; Petry, W.; Werner, E.
2010-01-01
Neutron Larmor diffraction (LD) is a high-resolution diffraction technique based on the Larmor precession of polarized neutrons. In contrast to conventional diffraction, LD does not depend on the accurate measurement of Bragg angles, and thus the resolution is independent of the beam collimation and monochromaticity. At present, a relative resolution for the determination of the crystal lattice spacing d of Δd/d∼10 -6 is achieved, i.e. at least one order of magnitude superior to conventional neutron or X-ray techniques. This work is a first step to explore the application of LD to high-resolution problems in the analysis of residual stresses, where both the accurate measurement of absolute d values and the possibility of measuring type II and III stresses may provide additional information beyond those accessible by conventional diffraction techniques. Data obtained from Inconel 718 samples are presented.
Neutron Larmor diffraction measurements for materials science
Energy Technology Data Exchange (ETDEWEB)
Repper, J., E-mail: julia_repper@web.de [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Keller, T. [Max-Planck-Institut fuer Festkoerperforschung, 70569 Stuttgart (Germany)] [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Hofmann, M. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Krempaszky, C. [Christian-Doppler-Labor fuer Werkstoffmechanik von Hochleistungslegierungen, TU Muenchen, 85747 Garching (Germany); Petry, W. [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), TU Muenchen, 85747 Garching (Germany); Werner, E. [Lehrstuhl fuer Werkstoffkunde und Werkstoffmechanik, TU Muenchen, 85747 Garching (Germany)
2010-05-15
Neutron Larmor diffraction (LD) is a high-resolution diffraction technique based on the Larmor precession of polarized neutrons. In contrast to conventional diffraction, LD does not depend on the accurate measurement of Bragg angles, and thus the resolution is independent of the beam collimation and monochromaticity. At present, a relative resolution for the determination of the crystal lattice spacing d of {Delta}d/d{approx}10{sup -6} is achieved, i.e. at least one order of magnitude superior to conventional neutron or X-ray techniques. This work is a first step to explore the application of LD to high-resolution problems in the analysis of residual stresses, where both the accurate measurement of absolute d values and the possibility of measuring type II and III stresses may provide additional information beyond those accessible by conventional diffraction techniques. Data obtained from Inconel 718 samples are presented.
The core mass-radius relation for giants - A new test of stellar evolution theory
Joss, P. C.; Rappaport, S.; Lewis, W.
1987-01-01
It is demonstrated here that the measurable properties of systems containing degenerate dwarfs can be used as a direct test of the core mass-radius relation for moderate-mass giants if the final stages of the loss of the envelope of the progenitor giant occurred via stable critical lobe overflow. This relation directly probes the internal structure of stars at a relatively advanced evolutionary state and is only modestly influenced by adjustable parameters. The measured properties of six binary systems, including such diverse systems as Sirius and Procyon and two millisecond pulsars, are utilized to derive constraints on the empirical core mass-radius relation, and the constraints are compared to the theoretical relation. The possibility that the final stages of envelope ejection of the giant progenitor of Sirius B occurred via critical lobe overflow in historical times is considered.
Ireland, Lewis G.; Browning, Matthew K.
2018-04-01
Some low-mass stars appear to have larger radii than predicted by standard 1D structure models; prior work has suggested that inefficient convective heat transport, due to rotation and/or magnetism, may ultimately be responsible. We examine this issue using 1D stellar models constructed using Modules for Experiments in Stellar Astrophysics (MESA). First, we consider standard models that do not explicitly include rotational/magnetic effects, with convective inhibition modeled by decreasing a depth-independent mixing length theory (MLT) parameter α MLT. We provide formulae linking changes in α MLT to changes in the interior specific entropy, and hence to the stellar radius. Next, we modify the MLT formulation in MESA to mimic explicitly the influence of rotation and magnetism, using formulations suggested by Stevenson and MacDonald & Mullan, respectively. We find rapid rotation in these models has a negligible impact on stellar structure, primarily because a star’s adiabat, and hence its radius, is predominantly affected by layers near the surface; convection is rapid and largely uninfluenced by rotation there. Magnetic fields, if they influenced convective transport in the manner described by MacDonald & Mullan, could lead to more noticeable radius inflation. Finally, we show that these non-standard effects on stellar structure can be fabricated using a depth-dependent α MLT: a non-magnetic, non-rotating model can be produced that is virtually indistinguishable from one that explicitly parameterizes rotation and/or magnetism using the two formulations above. We provide formulae linking the radially variable α MLT to these putative MLT reformulations.
On the stabilization of toroidal pinches by finite larmor radius effects and toroidal magnetic field
International Nuclear Information System (INIS)
Singh, R.; Weiland, J.
1989-01-01
The radial eigenvalue problem for internal modes in a large aspect ratio toriodal pinch has been solved. A particularly stable regime for a weak but nonzero toroidal magnetic field has been found. (31 refs.)
Finite Larmor radius effects on Alfven wave current drive in low-aspect ratio tokamaks
International Nuclear Information System (INIS)
Komoshvili, K.; Cuperman, S.; Bruma, C.
1998-01-01
Alfven wave current drive (AWCD) in low-aspect ratio (A≡R/a=1/ε > or approx. 1) tokamaks (LARTs) is studied numerically. For this, the full-wave equation (E parallel ≠0) with a Vlasov-based dielectric tensor is solved by relaxation techniques, subject to appropriate boundary conditions at the plasma centre and at the plasma-vacuum interface, as well as the concentric antenna current sheet and at the external metallic wall. A systematic investigation of the physical characteristics of the AWCD generated in LARTs when kinetic effects are considered is carried out and illustrative results are presented and discussed. (author)
Plasma balance equations based on orbit theory
International Nuclear Information System (INIS)
Lehnert, B.
1982-01-01
A set of plasma balance equations is proposed which is based on orbit theory and the particle distribution function, to provide means for theoretical analysis of a number of finite Larmor radius (FLR) phenomena without use of the Vlasov equation. Several important FLR effects originate from the inhomogeneity of an electric field in the plasma. The exact solution of a simple case shows that this inhomogeneity introduces fundamental changes in the physics of the particle motion. Thus, the periodic Larmor motion (gyration) is shifted in frequency and becomes elliptically polarized. Further, the non-periodic guiding-centre drift obtains additional components, part of which are accelerated such as to make the drift orbits intersect the equipotential surfaces of a static electric field. An attempt is finally made to classify the FLR effects, also with the purpose of identifying phenomena which have so far not been investigated. (author)
Energy Technology Data Exchange (ETDEWEB)
Ek-In, Surapat; Ruffolo, David [Department of Physics, Faculty of Science, Mahidol University, Bangkok (Thailand); Malakit, Kittipat [Department of Physics, Faculty of Science and Techonology, Thammasat University, Pathum Thani (Thailand); Shay, Michael A. [Department of Physics and Astronomy, University of Delaware, Newark, DE (United States); Cassak, Paul A., E-mail: kmalakit@gmail.com [Department of Physics and Astronomy, West Virginia University, Morgantown, WV (United States)
2017-08-20
We perform the first study of the properties of the Larmor electric field (LEF) in collisionless asymmetric magnetic reconnection in the presence of an out-of-plane (guide) magnetic field for different sets of representative upstream parameters at Earth’s dayside magnetopause with an ion temperature greater than the electron temperature (the ion-to-electron temperature ratio fixed at 2) using two-dimensional particle-in-cell simulations. We show that the LEF does persist in the presence of a guide field. We study how the LEF thickness and strength change as a function of guide field and the magnetospheric temperature and reconnecting magnetic field strength. We find that the thickness of the LEF structure decreases, while its magnitude increases when a guide field is added to the reconnecting magnetic field. The added guide field makes the Larmor radius smaller, so the scaling with the magnetospheric ion Larmor radius is similar to that reported for the case without a guide field. Note, however, that the physics causing the LEF is not well understood, so future work in other parameter regimes is needed to fully predict the LEF for arbitrary conditions. We also find that a previously reported upstream electron temperature anisotropy arises in the vicinity of the LEF region both with and without a guide field. We argue that the generation of the anisotropy is linked to the existence of the LEF. The LEF can be used in combination with the electron temperature anisotropy as a signature to effectively identify dayside reconnection sites in observations.
International Nuclear Information System (INIS)
Ek-In, Surapat; Ruffolo, David; Malakit, Kittipat; Shay, Michael A.; Cassak, Paul A.
2017-01-01
We perform the first study of the properties of the Larmor electric field (LEF) in collisionless asymmetric magnetic reconnection in the presence of an out-of-plane (guide) magnetic field for different sets of representative upstream parameters at Earth’s dayside magnetopause with an ion temperature greater than the electron temperature (the ion-to-electron temperature ratio fixed at 2) using two-dimensional particle-in-cell simulations. We show that the LEF does persist in the presence of a guide field. We study how the LEF thickness and strength change as a function of guide field and the magnetospheric temperature and reconnecting magnetic field strength. We find that the thickness of the LEF structure decreases, while its magnitude increases when a guide field is added to the reconnecting magnetic field. The added guide field makes the Larmor radius smaller, so the scaling with the magnetospheric ion Larmor radius is similar to that reported for the case without a guide field. Note, however, that the physics causing the LEF is not well understood, so future work in other parameter regimes is needed to fully predict the LEF for arbitrary conditions. We also find that a previously reported upstream electron temperature anisotropy arises in the vicinity of the LEF region both with and without a guide field. We argue that the generation of the anisotropy is linked to the existence of the LEF. The LEF can be used in combination with the electron temperature anisotropy as a signature to effectively identify dayside reconnection sites in observations.
Spin precession and spin waves in a chiral electron gas: Beyond Larmor's theorem
Karimi, Shahrzad; Baboux, Florent; Perez, Florent; Ullrich, Carsten A.; Karczewski, Grzegorz; Wojtowicz, Tomasz
2017-07-01
Larmor's theorem holds for magnetic systems that are invariant under spin rotation. In the presence of spin-orbit coupling this invariance is lost and Larmor's theorem is broken: for systems of interacting electrons, this gives rise to a subtle interplay between the spin-orbit coupling acting on individual single-particle states and Coulomb many-body effects. We consider a quasi-two-dimensional, partially spin-polarized electron gas in a semiconductor quantum well in the presence of Rashba and Dresselhaus spin-orbit coupling. Using a linear-response approach based on time-dependent density-functional theory, we calculate the dispersions of spin-flip waves. We obtain analytic results for small wave vectors and up to second order in the Rashba and Dresselhaus coupling strengths α and β . Comparison with experimental data from inelastic light scattering allows us to extract α and β as well as the spin-wave stiffness very accurately. We find significant deviations from the local density approximation for spin-dependent electron systems.
Study of tunneling time with Larmor clock and neutron absorption
International Nuclear Information System (INIS)
Hino, M.; Tasaki, S.; Ebisawa, T.; Kawai, T.; Utsuro, M.; Achiwa, N.
2001-01-01
Tunnel effect is one of the most typical quantum mechanical phenomena which cannot be understood in the classical physics. Though the tunnel phenomenon itself is precisely defined on the basis of quantum mechanics, tunneling time, the time for a particle to pass a tunnel barrier, has been a controversial issue because time is a parameter to show the rate of change of physical phenomena in quantum mechanics but has no corresponding quantum operator. In the present study, Larmor precession of the neutrons passing a Permalloy45 (PA) thin film was measured as a function of neutron incident angle to the film by using neutron spin-echo instrument at KUR and neutron interferometer at JRR-3. Results are compared with a calculation based on one-dimensional Schroedinger equation. The agreement between the experiment and the plane-wave simulation is very good which means that the neutrons are not described in particle picture here, and the Larmor time defined as number of spin precession divided by angular velocity no more represents the time for a particle to pass the barrier although it is a kind of the phase time. In order to emphasize the particle picture, effects of neutron absorption were considered theoretically. Larmor precession passing through a Fabry-Perot magnetic thin film which has two potential barriers (quantum well) for up-spin neutrons were measured for two cases that the film is hot neutron absorptive (PA-Ge-PA) and strongly absorptive (Se-Ge/Gd-Se). Here Ge, Gd and Se represent germanium, gadolinium and Supersendust, respectively. While down-spin neutrons feel only a small potential barrier. Spin-dependent reflectivity and transmission of the Fabry-Perot magnetic films were also measured as functions of the neutron incident angle to the film. Experimental results of the non-absorptive film show that the neutron spin precession cannot be treated as the classical motion of a magnetic moment feeling torque under applied magnetic field like the Larmor
International Nuclear Information System (INIS)
Ottonello, Giulio; Richet, Pascal
2014-01-01
The existing solubility data on noble gases in high-temperature silicate melts have been analyzed in terms of Scaling Particle Theory coupled with an ab initio assessment of the electronic, dispersive, and repulsive energy terms based on the Polarized Continuum Model (PCM). After a preliminary analysis of the role of the contracted Gaussian basis sets and theory level in reproducing appropriate static dipole polarizabilities in a vacuum, we have shown that the procedure returns Henry's law constants consistent with the values experimentally observed in water and benzene at T = 25 °C and P = 1 bar for the first four elements of the series. The static dielectric constant (ε) of the investigated silicate melts and its optical counterpart (ε ∞ ) were then resolved through the application of a modified form of the Clausius-Mossotti relation. Argon has been adopted as a probe to depict its high-T solubility in melts through an appropriate choice of the solvent diameter σ s , along the guidelines already used in the past for simple media such as water or benzene. The σ s obtained was consistent with a simple functional form based on the molecular volume of the solvent. The solubility calculations were then extended to He, Ne, and Kr, whose dispersive and repulsive coefficients are available from theory and we have shown that their ab initio Henry's constants at high T reproduce the observed increase with the static polarizability of the series element with reasonable accuracy. At room temperature (T = 25 °C) the calculated Henry's constants of He, Ne, Ar, and Kr in the various silicate media predict higher solubilities than simple extrapolations (i.e., Arrhenius plots) based on high-T experiments and give rise to smooth trends not appreciably affected by the static polarizabilities of the solutes. The present investigation opens new perspectives on a wider application of PCM theory which can be extended to materials of great industrial interest at the core of
Energy Technology Data Exchange (ETDEWEB)
Ottonello, Giulio, E-mail: giotto@dipteris.unige.it [DISTAV, Università di Genova, Corso Europa 26, 16132 Genova (Italy); Richet, Pascal [Institut de Physique du Globe, Rue Jussieu 2, 75005 Paris (France)
2014-01-28
The existing solubility data on noble gases in high-temperature silicate melts have been analyzed in terms of Scaling Particle Theory coupled with an ab initio assessment of the electronic, dispersive, and repulsive energy terms based on the Polarized Continuum Model (PCM). After a preliminary analysis of the role of the contracted Gaussian basis sets and theory level in reproducing appropriate static dipole polarizabilities in a vacuum, we have shown that the procedure returns Henry's law constants consistent with the values experimentally observed in water and benzene at T = 25 °C and P = 1 bar for the first four elements of the series. The static dielectric constant (ε) of the investigated silicate melts and its optical counterpart (ε{sup ∞}) were then resolved through the application of a modified form of the Clausius-Mossotti relation. Argon has been adopted as a probe to depict its high-T solubility in melts through an appropriate choice of the solvent diameter σ{sub s}, along the guidelines already used in the past for simple media such as water or benzene. The σ{sub s} obtained was consistent with a simple functional form based on the molecular volume of the solvent. The solubility calculations were then extended to He, Ne, and Kr, whose dispersive and repulsive coefficients are available from theory and we have shown that their ab initio Henry's constants at high T reproduce the observed increase with the static polarizability of the series element with reasonable accuracy. At room temperature (T = 25 °C) the calculated Henry's constants of He, Ne, Ar, and Kr in the various silicate media predict higher solubilities than simple extrapolations (i.e., Arrhenius plots) based on high-T experiments and give rise to smooth trends not appreciably affected by the static polarizabilities of the solutes. The present investigation opens new perspectives on a wider application of PCM theory which can be extended to materials of great
Ottonello, Giulio; Richet, Pascal
2014-01-28
The existing solubility data on noble gases in high-temperature silicate melts have been analyzed in terms of Scaling Particle Theory coupled with an ab initio assessment of the electronic, dispersive, and repulsive energy terms based on the Polarized Continuum Model (PCM). After a preliminary analysis of the role of the contracted Gaussian basis sets and theory level in reproducing appropriate static dipole polarizabilities in a vacuum, we have shown that the procedure returns Henry's law constants consistent with the values experimentally observed in water and benzene at T = 25 °C and P = 1 bar for the first four elements of the series. The static dielectric constant (ɛ) of the investigated silicate melts and its optical counterpart (ɛ(∞)) were then resolved through the application of a modified form of the Clausius-Mossotti relation. Argon has been adopted as a probe to depict its high-T solubility in melts through an appropriate choice of the solvent diameter σs, along the guidelines already used in the past for simple media such as water or benzene. The σs obtained was consistent with a simple functional form based on the molecular volume of the solvent. The solubility calculations were then extended to He, Ne, and Kr, whose dispersive and repulsive coefficients are available from theory and we have shown that their ab initio Henry's constants at high T reproduce the observed increase with the static polarizability of the series element with reasonable accuracy. At room temperature (T = 25 °C) the calculated Henry's constants of He, Ne, Ar, and Kr in the various silicate media predict higher solubilities than simple extrapolations (i.e., Arrhenius plots) based on high-T experiments and give rise to smooth trends not appreciably affected by the static polarizabilities of the solutes. The present investigation opens new perspectives on a wider application of PCM theory which can be extended to materials of great industrial interest at the core of
Larmor diffraction in the ferromagnetic superconductor UGe{sub 2}
Energy Technology Data Exchange (ETDEWEB)
Ritz, Robert; Pfleiderer, Christian [Physik Department E21, TU Muenchen, D-85748 Garching (Germany); Sokolov, Dmitry; Huxley, Andrew [School of Physics and Astronomy, Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Keller, Thomas [MPI fuer Festkoerperforschung, Heisenbergstr. 1, D-70569 Stuttgart (Germany)
2010-07-01
Larmor Diffaction (LD) is a neutron resonance spin-echo technique which allows the study of the lattice constant as well the distribution of lattice constants. It was traditionally thought that neutron spin-echo measurements cannot be used in materials such as superconductors or ferromagnets, because they strongly depolarize a polarized neutron beam. In UGe{sub 2} we are able to demonstrate that this technique may be applied in ferromagnetic superconductors with a magnetic Ising anisotropy. UGe{sub 2} exhibits two ferromagnetic phases which are separated by a transition at temperature T{sub x}. With increasing hydrostatic pressure superconductivity emerges at the pressure for which T{sub x} is suppressed. Using LD we studied the temperature dependence of the lattice constant as well as the distribution of lattice constants for all three axis of UGe{sub 2} down to 0.5 K and at pressures up to 12 kbar.
Theory of semicollisional kinetic Alfven modes in sheared magnetic fields
International Nuclear Information System (INIS)
Hahm, T.S.; Chen, L.
1985-02-01
The spectra of the semicollisional kinetic Alfven modes in a sheared slab geometry are investigated, including the effects of finite ion Larmor radius and diamagnetic drift frequencies. The eigenfrequencies of the damped modes are derived analytically via asymptotic analyses. In particular, as one reduces the resistivity, we find that, due to finite ion Larmor radius effects, the damped mode frequencies asymptotically approach finite real values corresponding to the end points of the kinetic Alfven continuum
Kohn's theorem, Larmor's equivalence principle and the Newton-Hooke group
International Nuclear Information System (INIS)
Gibbons, G.W.; Pope, C.N.
2011-01-01
Highlights: → We show that non-relativistic electrons moving in a magnetic field with trapping potential admits as relativity group the Newton-Hooke group. → We use this fact to give a group theoretic interpretation of Kohn's theorem and to obtain the spectrum. → We obtain the lightlike lift of the system exhibiting showing it coincides with the Nappi-Witten spacetime. - Abstract: We consider non-relativistic electrons, each of the same charge to mass ratio, moving in an external magnetic field with an interaction potential depending only on the mutual separations, possibly confined by a harmonic trapping potential. We show that the system admits a 'relativity group' which is a one-parameter family of deformations of the standard Galilei group to the Newton-Hooke group which is a Wigner-Inoenue contraction of the de Sitter group. This allows a group-theoretic interpretation of Kohn's theorem and related results. Larmor's theorem is used to show that the one-parameter family of deformations are all isomorphic. We study the 'Eisenhart' or 'lightlike' lift of the system, exhibiting it as a pp-wave. In the planar case, the Eisenhart lift is the Brdicka-Eardley-Nappi-Witten pp-wave solution of Einstein-Maxwell theory, which may also be regarded as a bi-invariant metric on the Cangemi-Jackiw group.
Theory and simulation of discrete kinetic beta induced Alfven eigenmode in tokamak plasmas
International Nuclear Information System (INIS)
Wang, X; Zonca, F; Chen, L
2010-01-01
It is shown, both analytically and by numerical simulations, that, in the presence of thermal ion kinetic effects, the beta induced Alfven eigenmode (BAE)-shear Alfven wave continuous spectrum can be discretized into radially trapped eigenstates known as kinetic BAE (KBAE). While thermal ion compressibility gives rise to finite BAE accumulation point frequency, the discretization occurs via the finite Larmor radius and finite orbit width effects. Simulations and analytical theories agree both qualitatively and quantitatively. Simulations also demonstrate that KBAE can be readily excited by the finite radial gradients of energetic particles.
The essential theory of fast wave current drive with full wave method
International Nuclear Information System (INIS)
Liu Yan; Gong Xueyu; Yang Lei; Yin Chenyan; Yin Lan
2007-01-01
The full wave numerical method is developed for analyzing fast wave current drive in the range of ion cyclotron waves in tokamak plasmas, taking into account finite larmor radius effects and parallel dispersion. the physical model, the dispersion relation on the assumption of Finite Larmor Radius (FLR) effects and the form of full wave be used for computer simulation are developed. All of the work will contribute to further study of fast wave current drive. (authors)
Stevanovic, Dragan
2015-01-01
Spectral Radius of Graphs provides a thorough overview of important results on the spectral radius of adjacency matrix of graphs that have appeared in the literature in the preceding ten years, most of them with proofs, and including some previously unpublished results of the author. The primer begins with a brief classical review, in order to provide the reader with a foundation for the subsequent chapters. Topics covered include spectral decomposition, the Perron-Frobenius theorem, the Rayleigh quotient, the Weyl inequalities, and the Interlacing theorem. From this introduction, the
International Nuclear Information System (INIS)
Rogister, A.L.
1999-01-01
'Subneoclassical' heat fluxes are predicted in the high collisionality regime by the revisited neoclassical theory, which includes the roles of Finite Larmor Radius effects and Inertia, that we published earlier. Unlike conventional neoclassical theory, the revisited theory further provides a non degenerate ambipolarity constraint which defines unambiguously the radial electric field. Together with the parallel momentum equation, the ambipolarity constraint leads, under some conditions, to radial electric field profiles with high negative shear akin to those observed in spontaneous edge transport barriers. The predictions of the theory are outlined, with emphasis laid on the interpretation of experimental results such as magnitude of the jumps, width of the shear layer, local scaling laws. Extension of the theory to triggered transitions and cold pulse propagation studies is suggested. (author)
Linear theory of equatorial spread F
International Nuclear Information System (INIS)
Hudson, M.K.; Kennel, C.F.
1975-01-01
A fluid dispersion relation for the drift and interchange (Rayleigh-Taylor) modes in a collisional plasma forms the basis for a linear theory of equatorial spread F. The collisional drift mode growth rate will exceed the growth rate of the Rayleigh-Taylor mode at short perpendicular wavelengths and density gradient scale lengths, and the drift mode can grow on top side as well as on bottom side density gradients. However, below the F peak, where spread F predominates, it is concluded that both the drift and the Rayleigh-Taylor modes contribute to the total spread F spectrum, the Rayleigh-Taylor mode dominating at long and the drift mode at short perpendicular wavelengths above the ion Larmor radius
Bonesini, Maurizio
2017-12-01
The FAMU (Fisica degli Atomi Muonici) experiment has the goal to measure precisely the proton Zemach radius, thus contributing to the solution of the so-called proton radius "puzzle". To this aim, it makes use of a high-intensity pulsed muon beam at RIKEN-RAL impinging on a cryogenic hydrogen target with an high-Z gas admixture and a tunable mid-IR high power laser, to measure the hyperfine (HFS) splitting of the 1S state of the muonic hydrogen. From the value of the exciting laser frequency, the energy of the HFS transition may be derived with high precision ( 10-5) and thus, via QED calculations, the Zemach radius of the proton. The experimental apparatus includes a precise fiber-SiPMT beam hodoscope and a crown of eight LaBr3 crystals and a few HPGe detectors for detection of the emitted characteristic X-rays. Preliminary runs to optimize the gas target filling and its operating conditions have been taken in 2014 and 2015-2016. The final run, with the pump laser to drive the HFS transition, is expected in 2018.
The earth's radius and the G variation
International Nuclear Information System (INIS)
Canuto, V.M.; City Coll., New York
1981-01-01
It has been assumed that if the gravitational constant G was larger in the past, the Earth's radius had to be smaller. The assertion holds provided the input from microphysics (in particular the equation of state) is independent of G. While this is true for some theories of gravity with variable G it is not so in the scale covariant theory, where the pressure can be affected by a variable G in a way that, for a constant mass of the Earth, a larger G in the past implies a larger Earth's radius. Comparison with recent palaeomagnetic data is presented. (author)
Larmor diffraction studies on the ferromagnetic superconductor UGe{sub 2}
Energy Technology Data Exchange (ETDEWEB)
Ritz, Robert; Pfleiderer, Christian [Physik Department E21, TU Muenchen, Garching (Germany); Sokolov, Dmitry; Huxley, Andrew D. [School of Physics and Astronomy, and Centre for Science at Extreme Conditions, The University of Edinburgh (United Kingdom); Keller, Thomas [MPI fuer Festkoerperforschung, Stuttgart (Germany)
2011-07-01
Larmor diffraction (LD) is a novel technique based on the Larmor precession of polarized neutrons that surpasses the resolution of conventional scattering methods by two orders of magnitude. For a long time it was thought that it is not possible to measure LD on systems with depolarizing properties, such as ferromagnets. We present thermal expansion measurements under pressure by means of Larmor diffraction (LD) on the superconducting Ising ferromagnet UGe{sub 2}. LD allowed us to measure magnetization and thermal expansion under pressure in the same setup and hence to directly compare transition temperatures. We found that the thermal expansion near T{sub X}, the transition between two ferromagnetic phases which is believed to drive superconductivity, shows a clear transition in the b- and c-axis under pressure at a temperature a few K higher than for the a-axis and the ferromagnetic Bragg peak. We are considering different mechanisms how this may be connected with the superconductivity in UGe{sub 2}.
Collisionless two-fluid theory of toroidal ηi stability
International Nuclear Information System (INIS)
Mondt, J.; Weiland, J.
1989-01-01
A collisionless two-fluid theory based on a fourteen-moment generalization of the 'double-adiabatic' equations is developed to lowest order in the Larmor radius parameter, and applied to derive the toroidal η i stability boundary for all values of the ratio of the density gradient scale length divided by the field curvature length. The present model is an improvement over existing collisional two-fluid models in view of the collisionless nature of the η i instability, while retaining the advantage over kinetic theory of the practability of mode-coupling simulations. The linear stability boundary, linear growth rate and real frequency agree fairly accurately with draft-kinetic theory
Larmor precession and dwell time of a relativistic particle scattered by a rectangular quantum well
Li, Z J; Liang, J J; Liang, J Q
2003-01-01
The Larmor precession of a relativistic neutral spin particle in a uniform constant magnetic field confined to the region of a one-dimensional rectangular potential well is investigated. The spin precession serves as a clock to measure the time spent by a quantum particle dwelling at a potential well. With the help of a general spin coherent state it is explicitly shown that the spin precession time is equal to the dwell time in the first-order approximation of the infinitesimal field limit. The comparison of the time in a potential well with that in free space shows apparent superluminality.
A neutron spectrometer based on the combination of time-of-flight and Larmor modulation
International Nuclear Information System (INIS)
Mulder, F.M.; Kreuger, R.; Grigoriev, S.V.; Kraan, W.H.; Rekveldt, M.Th.; Van Well, A.A.
1999-01-01
A study on the feasibility of neutron beam instrumentation that applies Larmor modulation for incoming, and time-of-flight for scattered wavelength determination (or vice versa) is currently under way at IRI. The instrument resulting from this combination can in principle measure quasi elastic and inelastic scattering with a flexible resolution and dynamic range. An important difference with current spectrometers is that there is no selection of neutron wavelengths for either the incoming beam (direct geometry) or scattered beam (inverted geometry). Therefore much of the available flux is used and there is no a priory selection of the energy transfer range and resolution. This instrument will be mainly applicable for quasi-elastic scattering and complex line shapes that are extended over a broad range in energy transfer. Line shapes can be measured directly in Fourier space, which is often advantageous. Due to signal to noise considerations, this instrument will be less suitable for the determination of weak, discrete energy transfer signals. A requirement for the Larmor modulator is that it can work with a white neutron beam. This can be realised for neutrons having a wavelength above ∼ 0.1 nm by use of 'adiabatic resonance π flippers'. This type of instrument may be applied at the future ESS pulsed neutron source in order to complement current spectrometers. (author)
Phase Grouping of Larmor Electrons by a Synchronous Wave in Controlled Magnetrons
Energy Technology Data Exchange (ETDEWEB)
Kazakevich, G. [MUONS Inc., Batavia; Johnson, R. [MUONS Inc., Batavia; Lebedev, V. [Fermilab; Yakovlev, V. [Fermilab
2018-04-01
A simplified analytical model based on the charge drift approximation has been developed. It considers the resonant interaction of the synchronous wave with the flow of Larmor electrons in a magnetron. The model predicts stable coherent generation of the tube above and below the threshold of self-excitation. This occurs if the magnetron is driven by a sufficient resonant injected signal (up to -10 dB). The model substantiates precise stability, high efficiency and low noise at the range of the magnetron power control over 10 dB by variation of the magnetron current. The model and the verifying experiments with 2.45 GHz, 1 kW magnetrons are discussed.
International Nuclear Information System (INIS)
Bulgakov, M.I.; Dzheparov, F.S.; Gul'ko, A.D.; Shestopal, V.E.; Stepanov, S.V.; Trostin, S.S.
1989-01-01
β-NMR-spectroscopy investigations of the resonance at double Larmor frequency of β-active nuclei 8 Li in LiF polycrystals are presented. The qualitative analysis of the dislocation influence on this resonance is developed. An important role of correlations in dislocation distributions as well as high responsivity of this resonance to quadrupole interactions are found. 13 refs.; 2 figs
Giannini, M. M.; Santopinto, E.
2013-01-01
The recent values of the proton charge radius obtained by means of muonic-hydrogen laser spectroscopy are about $4\\%$ different from the electron scattering data. It has been suggested that the proton radius is actually measured in different frames and that, starting from a non relativistic quark model calculation, the Lorentz transformation of the form factors accounts properly for the discepancy. We shall show that the relation between the charge radii measured in different frames can be de...
International Nuclear Information System (INIS)
Gerhardt, S.; Belova, E.V.; Yamada, M.; Ji, H.; Inomoto, M.; Jacobson, C.M.; Maqueda, R.; McGeehan, B.; Ren, Y.
2008-01-01
Oblate field-reversed configurations FRCs have been sustained for >300 (micro)s, or >15 magnetic diffusion times, through the use of an inductive solenoid. These argon FRCs can have their poloidal flux sustained or increased, depending on the timing and strength of the induction. An inward pinch is observed during sustainment, leading to a peaking of the pressure profile and maintenance of the FRC equilibrium. The good stability observed in argon (and krypton) does not transfer to lighter gases, which develop terminal co-interchange instabilities. The stability in argon and krypton is attributed to a combination of external field shaping, magnetic diffusion, and finite-Larmor radius effects.
Theory of steady state plasma flow and confinement in a periodic magnetic field
International Nuclear Information System (INIS)
Brown, M.G.
1981-02-01
The steady flow of plasmas through spatially periodic magnetic fields is examined, and a theoretical model is developed for the case of axisymmetric geometry. The externally applied magnetic fields can be cusps or mirrors joined end to end; electrons are then localised by these fields because of their small Larmor radius, while the ions can traverse the magnetic mirrors. The properties of the model equations are studied and dimensionless parameters which appear are interpreted. Numerical methods used in steady flow applications are reviewed, and some techniques of solution for the model equations are discussed. A solution method involving numerical integration of time-dependent equations is described, which approaches the steady state asymptotically; results from this method are presented and compared with the results from perturbation theory. (author)
Theory of neoclassical tearing modes and its application to ITER-FEAT
International Nuclear Information System (INIS)
Pustovitov, V.D.; Mikhailovskii, A.B.; Konovalov, S.V.; Zvonkov, A.V.; Kobayashi, N.; Mukhovatov, V.S.
2001-01-01
Neoclassical tearing modes (NTM) can be responsible for beta limitation in long-pulse ITER discharges. The excitation and growth of NTM are governed by the competing bootstrap current, polarization current and so-called Δ' effects. Also, the magnetic well and Electron Cyclotron Current Drive (ECCD) can stabilize the NTM. We study analytically and numerically all the effects with a particular emphasis on the polarization current in the analytical part of our study. We show that the polarization current description requires a generalized transport theory including the hyperviscosity, electron pressure gradient and, as well, the finite ion Larmor radius effects in the perpendicular current. The profile function nonstationarity must be taken into account for calculation of the island rotation frequency. Results of numerical simulation of NTM suppression by modulated ECCD in ITER are presented. (author)
Energy Technology Data Exchange (ETDEWEB)
Mihovilovic, Miha [Institut fuer Kernphysik, Johannes-Gutenberg-Universitaet, Mainz (Germany)
2016-07-01
The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the presently best value obtained from elastic scattering experiments remains unexplained and represents a burning problem of today's nuclear physics. Therefore, several new experiments are underway, committed to provide new insight into the problem. High-precision electron scattering experiments are in progress at the Jefferson Lab and the Mainz Microtron. As a counterpart to these measurements, a muon-proton scattering experiment is envisioned at the Paul Scherrer Institute. Together with the nuclear scattering experiments, new atomic measurements are underway at the Max Planck Institute in Garching, which aim to further improve also the spectroscopic results on electronic hydrogen. These experiments are complemented by extensive theoretical efforts focused on studying various processes contributing to the atomic Lamb shift measurements that could explain the difference, as well as on pursuing different ways to interpret nuclear form-factor measurements, which could lead to a consistent value of the radius. In this presentation the currently best proton radius measurements are summarized, and the importance of the observed inconsistency between the hydrogen and the muonic-hydrogen data is discussed. Selected new experiments dedicated to remeasuring the radius are described, and the results of the MAMI experiment are presented.
Understanding the mass-radius relation for sub-Neptunes: radius as a proxy for composition
Energy Technology Data Exchange (ETDEWEB)
Lopez, Eric D.; Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
2014-09-01
Transiting planet surveys like Kepler have provided a wealth of information on the distribution of planetary radii, particularly for the new populations of super-Earth- and sub-Neptune-sized planets. In order to aid in the physical interpretation of these radii, we compute model radii for low-mass rocky planets with hydrogen-helium envelopes. We provide model radii for planets 1-20 M {sub ⊕}, with envelope fractions 0.01%-20%, levels of irradiation 0.1-1000 times Earth's, and ages from 100 Myr to 10 Gyr. In addition we provide simple analytic fits that summarize how radius depends on each of these parameters. Most importantly, we show that at fixed H/He envelope fraction, radii show little dependence on mass for planets with more than ∼1% of their mass in their envelope. Consequently, planetary radius is to a first order a proxy for planetary composition, i.e., H/He envelope fraction, for Neptune- and sub-Neptune-sized planets. We recast the observed mass-radius relationship as a mass-composition relationship and discuss it in light of traditional core accretion theory. We discuss the transition from rocky super-Earths to sub-Neptune planets with large volatile envelopes. We suggest ∼1.75 R {sub ⊕} as a physically motivated dividing line between these two populations of planets. Finally, we discuss these results in light of the observed radius occurrence distribution found by Kepler.
Kinetic theory of tearing instabilities
International Nuclear Information System (INIS)
Drake, J.F.; Lee, Y.C.
1977-01-01
The transition of the tearing instability from the collisional to the collisionless regime is investigated kinetically using a Fokker--Planck collision operator to represent electron-ion collisions. As a function of the collisionality of the plasma, the tearing instability falls into three regions, which are referred to as collisionless, semi-collisional, and collisional. The width Δ of the singular layer around kxB 0 =0 is limited by electron thermal motion along B 0 in the collisional and semi-collisional regimes and is typically smaller than rho/sub i/, the ion Larmor radius. Previously accepted theories, which are based on the assumption Δvery-much-greater-thanrho/sub i/, are found to be valid only in the collisional regime. The effects of density and temperature gradients on the instabilities are also studied. The tearing instability is only driven by the temperature gradient in the collisional and semi-collisional regimes. Numerical calculations indicate that the semi-collisional tearing instability is particularly relevant to present day high temperature tokamak discharges
Electric arc radius and characteristics
International Nuclear Information System (INIS)
Fang, T.M.
1980-01-01
The heat transfer equation of an arc discharge has been solved. The arc is assumed to be a cylinder with negligible axial variation and the dominant heat transfer process is conduction radially inside the column and radiation/convection at the outside edge. The symmetric consideration allows a simple one-dimensional formulation. By taking into account proper variation of the electrical conductivity as function of temperature, the heat balance equation has been solved analytically. The radius of the arc and its current-field characteristics have also been obtained. The conventional results that E approx. I 0 5385 and R approx. I 0 7693 with E being the applied field, I the current, and R the radius of the cylindrical arc, have been proved to be simply limiting cases of our more general characteristics. The results can be applied quite widely including, among others, the neutral beam injection project in nuclear fusion and MHD energy conversion
Czech Academy of Sciences Publication Activity Database
Drnovšek, R.; Müller, Vladimír
2014-01-01
Roč. 62, č. 9 (2014), s. 1197-1204 ISSN 0308-1087 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : joint numerical range * numerical radius Subject RIV: BA - General Mathematics Impact factor: 0.738, year: 2014 http://www.tandfonline.com/doi/abs/10.1080/03081087.2013.816303
QED confronts the radius of the proton
De Rujula, A
2011-01-01
Recent results on muonic hydrogen [1] and the ones compiled by CODATA on ordinary hydrogen and $ep$-scattering [2] are $5\\sigma$ away from each other. Two reasons justify a further look at this subject: 1) One of the approximations used in [1] is not valid for muonic hydrogen. This amounts to a shift of the proton's radius by $\\sim 3$ of the standard deviations of [1], in the "right" direction of data-reconciliation. In field-theory terms, the error is a mismatch of renormalization scales. Once corrected, the proton radius "runs", much as the QCD coupling "constant" does. 2) The result of [1] requires a choice of the "third Zemach moment". Its published independent determination is based on an analysis with a $p$-value --the probability of obtaining data with equal or lesser agreement with the adopted (fit form-factor) hypothesis-- of $3.92\\times 10^{-12}$. In this sense, this quantity is not empirically known. Its value would regulate the level of "tension" between muonic- and ordinary-hydrogen results, curr...
Calculation of nuclear radius using alpha decay
International Nuclear Information System (INIS)
Castro, R.B. de.
1988-01-01
Using a Quantum Theory approach for the Alpha-Decay process, a formula is deduced for determination of the nuclear radius of the s-state, that is, a nuclear model with a spherical shell. The hypothesis that it is possible to individualize the alpha particle and the daughter nucleus at the moment of the alpha particle emission is considered. In considered in these conditions, the treatment of a two body problem considered as point particles, repelling each other by Coulomb's Law. Using the new values of the fundamental physical constants, experimentally determinated, by substitution of their numerical values in the proposed, new values of nuclear radii are obtained. These values are compared with those found in the literature. (author) [pt
International Nuclear Information System (INIS)
Van Well, A.A.; Bleuel, M.; Pappas, C.
2011-01-01
Neutron Spin Echo (NSE) spectrometers typically cover a dynamic range of three orders of magnitude at a given wavelength. At long Fourier times the limits are given by the homogeneity of precession fields. At short Fourier times, the quasi-elastic approximation and the NSE formalism mark a methodological limit. We propose to overcome this limitation and by combining Time Of Flight with Larmor precession to extend the capabilities of Neutron Spin Echo spectrometers towards short Fourier times. TOFLAR should be easily implemented on NSE spectrometers equipped with a chopper system such as IN15 or the planned WASP. (authors)
The creep bending of short radius pipe bends
International Nuclear Information System (INIS)
Spence, John
1975-01-01
In existing and proposed liquid metal fast breeder reactor design the pipework has considerable importance. Parts of the LMFBR include thin walled short radius bends which are expected to operate in the creep regime. In linear elasticity it is known that the assumption of long radius bends is not too severe as far as the flexibility characteristics are concerned although some modifications are necessary for accurate determination of the stresses. No data exists for nonlinear creep. Current work is aimed at elucidating the effect of the various assumptions common to linear elastic theory in so far as they affect the creep characteristics of bends on systems. Herein an energy based analysis using a simple n power constitutive law for stationary creep is employed to derive basic design data for flexibilities and stresses which will be necessary before complete systems can be assessed for creep. The analysis shows on comparison with the long radius work that the assumption of R>r is not much more restrictive in creep than for linear elasticity. Flexibilities for short radius bends appear to be well approximated by the long radius values. Thus the attractive reference stress information already derived may be used directly to find deformations without a complete knowledge of the constitutive relationship. However, stresses are somewhat different. Fortunately the maximum deviation occurs at relatively low levels of stress, the peak stresses being in fair agreement. When n=1 the present results reduce essentially to those obtained from existing linear elastic theory
Numerical Test of Different Approximations Used in the Transport Theory of Energetic Particles
Qin, G.; Shalchi, A.
2016-05-01
Recently developed theories for perpendicular diffusion work remarkably well. The diffusion coefficients they provide agree with test-particle simulations performed for different turbulence setups ranging from slab and slab-like models to two-dimensional and noisy reduced MHD turbulence. However, such theories are still based on different analytical approximations. In the current paper we use a test-particle code to explore the different approximations used in diffusion theory. We benchmark different guiding center approximations, simplifications of higher-order correlations, and the Taylor-Green-Kubo formula. We demonstrate that guiding center approximations work very well as long as the particle's unperturbed Larmor radius is smaller than the perpendicular correlation length of the turbulence. Furthermore, the Taylor-Green-Kubo formula and the definition of perpendicular diffusion coefficients via mean square displacements provide the same results. The only approximation that was used in the past in nonlinear diffusion theory that fails is to replace fourth-order correlations by a product of two second-order correlation functions. In more advanced nonlinear theories, however, this type of approximation is no longer used. Therefore, we confirm the validity of modern diffusion theories as a result of the work presented in the current paper.
International Nuclear Information System (INIS)
Woolley, R.; Dean, J.
1976-01-01
Photoelectric observations of the light curves of RX Eri obtained in B, V and I, and radial velocity determinations, are combined to determine the radius by a method originally proposed by van Hoof which avoids matching colours in the rising and falling branches of the light curve and concentrates on the falling branch. The results agree well with those from other stars determined by the normal Baade-Wesselink method, but the method is easier to apply if the colour curve is flat in the falling branch. The parameters found for the star are r 0 = 5.5 Sun, mass = 0.45 Sun, and Msub(v) = + 0sup(m).54. (author)
Nonlinear buckling analyses of a small-radius carbon nanotube
International Nuclear Information System (INIS)
Liu, Ning; Li, Min; Jia, Jiao; Wang, Yong-Gang
2014-01-01
Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained
Nonlinear buckling analyses of a small-radius carbon nanotube
Energy Technology Data Exchange (ETDEWEB)
Liu, Ning, E-mail: liuxiao@ase.buaa.edu.cn; Li, Min; Jia, Jiao [School of Aeronautic Science and Engineering, Beihang University, Beijing 100091 (China); Wang, Yong-Gang [Department of Applied Mechanics, China Agricultural University, Beijing 100083 (China)
2014-04-21
Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained.
Puzzling out the proton radius puzzle
Directory of Open Access Journals (Sweden)
Mihovilovič Miha
2014-01-01
Full Text Available The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today’s nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described.
Puzzling out the proton radius puzzle
Energy Technology Data Exchange (ETDEWEB)
Mihovilovič, M.; Merkel, H.; Weber, A. [Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 45, 55128 Mainz (Germany)
2016-01-22
The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today’s nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described.
Critical cladding radius for hybrid cladding modes
Guyard, Romain; Leduc, Dominique; Lupi, Cyril; Lecieux, Yann
2018-05-01
In this article we explore some properties of the cladding modes guided by a step-index optical fiber. We show that the hybrid modes can be grouped by pairs and that it exists a critical cladding radius for which the modes of a pair share the same electromagnetic structure. We propose a robust method to determine the critical cladding radius and use it to perform a statistical study on the influence of the characteristics of the fiber on the critical cladding radius. Finally we show the importance of the critical cladding radius with respect to the coupling coefficient between the core mode and the cladding modes inside a long period grating.
Linear theory of the tearing instability in axisymmetric toroidal devices
International Nuclear Information System (INIS)
Rogister, A.; Singh, R.
1988-08-01
We derive a very general kinetic equation describing the linear evolution of low m/l modes in axisymmetric toroidal plasmas with arbitrary cross sections. Included are: Ion sound, inertia, diamagnetic drifts, finite poloidal beta, and finite ion Larmor radius effects. Assuming the magnetic surfaces to form a set of nested tori with circular cross sections of shifted centers, and introducing adequate simplifications justified by our knowledge of experimental tokamak plasmas, we then obtain explicitely the sets of equations describing the coupling of the quasimodes 0/1, 1/1, 2/1, and, for m≥2, m/1, (m+1)/1. By keeping finite aspect ratio effects into account when calculating the jump of the derivative of the eigenfunction, it is shown that the theory can explain the rapid evolution, within one sawtooth period, of the growth rate of the sawteeth precursors from resistive values to magnetohydrodynamic ones. The characteristics thus theoretically required from current profiles in sawtoothing discharges have clearly been observed. Other aspects of the full theory could be relevant to the phenomenon of major disruptions. (orig.)
International Nuclear Information System (INIS)
Vlad, G.
1988-01-01
The linear stability of the electrostatic drift waves in slab geometry has been studied analytically and numerically. The effects of magnetic field with shear, of the finite Larmor radius, of an electron streaming, of a temperature gradient and of collisions have been retained. The analytical solution has been obtained using the matched asymptotic expansion technique, and an expression for the critical streaming parameter has been derived. Finally, assuming that the transport in the Reversed Field Pinches is dominated by this instability, a scaling law for the temperature in such machine is derived
Nuclear charge radius of $^{12}$Be
Krieger, Andreas; Bissell, Mark L; Frömmgen, Nadja; Geppert, Christopher; Hammen, Michael; Kreim, Kim; Kowalska, Magdalena; Krämer, Jörg; Neff, Thomas; Neugart, Rainer; Neyens, Gerda; Nörtershäuser, Wilfried; Novotny, Christian; Sanchez, Rodolfo; Yordanov, Deyan T
2012-01-01
The nuclear charge radius of $^{12}$Be was precisely determined using the technique of collinear laser spectroscopy on the $2s_{1/2}\\rightarrow 2p_{1/2, 3/2}$ transition in the Be$^{+}$ ion. The mean square charge radius increases from $^{10}$Be to $^{12}$Be by $\\delta ^{10,12} = 0.69(5)$ fm$^{2}$ compared to $\\delta ^{10,11} = 0.49(5)$ fm$^{2}$ for the one-neutron halo isotope $^{11}$Be. Calculations in the fermionic molecular dynamics approach show a strong sensitivity of the charge radius to the structure of $^{12}$Be. The experimental charge radius is consistent with a breakdown of the N=8 shell closure.
Kinetic theory of rf current drive and helicity injection
International Nuclear Information System (INIS)
Mett, R.R.
1992-01-01
Current drive and helicity injection by plasma waves are examined with the use of kinetic theory. The Vlasov equation yields a general current drive formula that contains resonant and nonresonant (ponderomotivelike) contributions. Standard quasilinear current drive is described by the former, while helicity current drive may be contained in the latter. Since direct analytical comparison of the sizes of the two terms is, in general, difficult, a new approach is taken. Solution of the drift-kinetic equation shows that the standard Landau damping/transit time magnetic pumping quasilinear diffusion coefficient is the only contribution to steady-state current drive to leading order in ε=ρ L /l, where ρ L is the Larmor radius and l is the inhomogeneity scale length. All nonresonant contributions, including the helicity, appear at higher order, after averages are taken over a flux surface, over azimuth, and over time. Consequently, at wave frequencies well below the electron cyclotron frequency, a wave helicity flux perpendicular to the magnetic field does not influence the parallel motion of electrons to leading order and therefore will not drive a significant current. Any current associated with a wave helicity flux is then either ion current (and thus inefficient) or electron current stemming from effects not included in the drift-kinetic treatment, such as cyclotron, collisional, or nonlinear (i.e., not quasilinear)
Theory of Bernstein waves coupling with loop antennas
International Nuclear Information System (INIS)
Brambilla, M.
1987-04-01
We present a fully three-dimensional theory of antenna coupling to Ion Bernstein Waves near the first harmonic of the ion cyclotron resonance in tokamak plasmas. The boundary conditions in vacuum are solved analytically for arbitrary orientation of the antenna and Faraday screen conductors. The wave equations in the plasma, which include Finite Larmor Radius and finite electron inertia effects, cyclotron and harmonic damping by the ions, and Landau and collisional damping by the electrons, are solved numerically using a Finite Elements discretisation with cubic Hermite interpolating functions. Applications to Alcator C give reasonably good agreement between the calculated and measured radiation resistance in the range in which efficient heating is observed; outside this range the calculated resistance is lower than the experimental one. In general, the coupling efficiency is found to be very sensitive to the edge plasma density, good coupling requiring a low density plasma layer in the vicinity of the Faraday screen. Coupling also improves with increasing scrape-off ion temperature, and is appreciably better for antisymmetric than for symmetric toroidal current distributions in the antenna. (orig.)
International Nuclear Information System (INIS)
Nakashima, Kenichi; Stoller, Roger E; Xu, Haixuan
2015-01-01
The recombination radius of a Frenkel pair is a fundamental parameter for the object kinetic Monte Carlo (OKMC) and mean field rate theory (RT) methods that are used to investigate irradiation damage accumulation in irradiated materials. The recombination radius in bcc Fe has been studied both experimentally and numerically, however there is no general consensus about its value. The detailed atomistic processes of recombination also remain uncertain. Values from 1.0a 0 to 3.3a 0 have been employed as a recombination radius in previous studies using OKMC and RT. The recombination process of a Frenkel pair is investigated at the atomic level using the self-evolved atomistic kinetic Monte Carlo (SEAKMC) method in this paper. SEAKMC calculations reveal that a self-interstitial atom recombines with a vacancy in a spontaneous reaction from several nearby sites following characteristic pathways. The recombination radius of a Frenkel pair is estimated to be 2.26a 0 by taking the average of the recombination distances from 80 simulation cases. In addition, we apply these procedures to the capture radius of a self-interstitial atom by a vacancy cluster. The capture radius is found to gradually increase with the size of the vacancy cluster. The fitting curve for the capture radius is obtained as a function of the number of vacancies in the cluster. (paper)
Radius crossover sign: an indication of malreduced radius shaft greenstick fractures.
Wright, Patrick B; Crepeau, Allison E; Herrera-Soto, José A; Price, Charles T
2012-06-01
Radius shaft greenstick fractures in children can be a challenging injury to treat because angulation and rotational alignment are difficult to assess. In this report, we describe a simple method for analyzing the deformity and identifying rotational and angular malalignment. This technique involves analyzing the forearm radiographs as 2 segments, proximal and distal, and assuring that the rotational position of each matches the other. We present 3 cases of proximal radius greenstick fractures in malalignment to demonstrate the radius crossover sign. Identifying the radius crossover sign, and proceeding with further closed reduction may prevent deformity that could otherwise result in a significant loss of forearm motion. Level V.
A Maximum Radius for Habitable Planets.
Alibert, Yann
2015-09-01
We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.
Study Application of RADIUS Protocol on Ethernet
Institute of Scientific and Technical Information of China (English)
GUO Fang; YANG Huan-yu; LI Hong
2004-01-01
This paper presents how to apply the RADIUS (Remote Authentication Dial In User Service)protocol ,which is generally applied to dial-up network, to the authentication & charge of Broad Band accessing control system on Ethernet. It is provided that the Broad Band accessing control system included a self-designed communication protocol is used in communicating between an terminal user and Network Access Server .The interface module on the servers side and the Radius system is also given in this article.
Mass-Radius Relations of Z and Higgs-Like Bosons
Directory of Open Access Journals (Sweden)
Lehnert B.
2014-01-01
Full Text Available Relations between the rest mass and the effective radius are deduced for the Z boson and the experimentally discovered Higgs-like boson, in terms of a revised quantum electrodynamic (RQED theory. The latter forms an alternative to the Standard Model of elementary particles. This results in an effective radius of the order of 10 E-18 m for a rest mass of 125 GeV.
Kinetic theory of magnetic island stability in tokamaks
International Nuclear Information System (INIS)
Zabiego, M.; Garbet, X.
1993-10-01
The non linear behavior of low and large wave number tearing modes is studied. The emphasis is layed on diamagnetic effects. A kinetic equation, including transport processes associated with a background of microturbulence, is used to describe the electron component. Such transport processes are shown to play a significant role in the adjustment of density and temperature profile and also in the calculation of the island rotation frequency. The fluctuating electric potential is calculated self-consistently, using the differential response of electrons and ions. Four regimes are considered, related to island width (smaller or larger than an ion Larmor radius) and transport regime (electron-ion collisions or electro-viscosity dominated). It is shown that diamagnetism does not influence the island stability for small island width in the viscous regime, as long as the constant A constraint is maintained. It turns out that the release of this constraint may strongly modify the previously calculated stability thresholds. Finally, it is found that diamagnetism is destabilizing (stabilizing) for island width smaller (larger) than an ion Larmor radius, in both resistive and viscous regimes. A typical island evolution scenario is studied which shows that even large scale tearing modes with positive Δ ' could saturate to island width of order of a few ion Larmor radii. Illustrative Δ ' threshold and island saturation size are calculated. (authors). 31 refs., 5 figs., 3 tabs
Spectral Radius and Hamiltonicity of Graphs
Czech Academy of Sciences Publication Activity Database
Fiedler, Miroslav; Nikiforov, V.
2010-01-01
Roč. 432, č. 9 (2010), s. 2170-2173 ISSN 0024-3795 Institutional research plan: CEZ:AV0Z10300504 Keywords : Hamiltonian cycle * Hamiltonian path * spectral radius Subject RIV: BA - General Mathematics Impact factor: 1.005, year: 2010
Cost Effective RADIUS Authentication for Wireless Clients
Directory of Open Access Journals (Sweden)
Alexandru ENACEANU
2010-12-01
Full Text Available Network administrators need to keep administrative user information for each network device, but network devices usually support only limited functions for user management. WLAN security is a modern problem that needs to be solved and it requires a lot of overhead especially when applied to corporate wireless networks. Administrators can set up a RADIUS server that uses an external database server to handle authentication, authorization, and accounting for network security issues.
Relation between second-order moment radius of focal spot and near field distribution of laser beam
International Nuclear Information System (INIS)
Gao Xueyan; Su Yi; Ye Yidong; Guan Youguang
2011-01-01
In order to analyze the effect of aberration of amplitude and phase of laser beam on second-order moment radius of focal spot, based on the Fraunhofer formula for light wave scalar diffraction theory and the definition of second-order moment radius, the general expression for focal spot second-order moment radius depending on the complex amplitude of near field is derived. The second-order moment radius of the focal spot depending on intensity distribution and phase distribution of near field is derived, and its clear physical meaning is described. The second-order moment radius and the divergence angle of focal spot may be easily calculated with the second-order moment radius expression of focal spot. At last, the divergence angles of focal spots of several kinds of Gaussian laser beams are calculated directly, and the results are in accordance with those in the related references. (authors)
Upper pinch radius limit in EXTRAP
International Nuclear Information System (INIS)
Lehnert, B.
1989-12-01
A simple static equilibrium model of the Z-pinch is considered where a hot plasma core is surrounded by a cold-mantle (gas blanket). The pinch radius, defined as the radial extension of the fully ionized plasma core, is uniquely determined by the plasma particle. momentum and heat balance equations. In Extrap configurations an octupole field is introduced which imposes a magnetic separatrix on Z-pinch geometry. This makes the conditions for Extrap equilibrium 'overdetermined' when the characteristic pinch radium given by the plasma parameters tends to exceed the characteristic radius of the magnetic separatrix. In this case no conventional pinch equilibrium can exist, and part of the current which is forced into the plasma discharge by external sources must be channelled outside of the separatrix, i.e. into the surrounding support structure of the Extrap conductors and the vessel walls. A possibly existing bootstrap current in the plasma boundary layer is further expected to be 'scraped off' in this case. The present paper gives some illustrations of the marginal case of this upper pinch radius limit, in a state where the pinch current is antiparallel to the external rod currents which generate the octupole field. (authors)
Mass-Radius diagram for compact stars
International Nuclear Information System (INIS)
Carvalho, G A; Jr, R M Marinho; Malheiro, M
2015-01-01
The compact stars represent the final stage in the evolution of ordinary stars, they are formed when a star ceases its nuclear fuel, in this point the process that sustain its stability will stop. After this, the internal pressure can no longer stand the gravitational force and the star colapses [2]. In this work we investigate the structure of these stars which are described by the equations of Tolman-Openheimer-Volkof (TOV) [1]. These equations show us how the pressure varies with the mass and radius of the star. We consider the TOV equations for both relativistic and non-relativistic cases. In the case of compact stars (white dwarfs and neutron stars) the internal pressure that balances the gravitational pressure is essentialy the pressure coming from the degeneracy of fermions. To have solved the TOV equations we need a equation of state that shows how this internal pressure is related to the energy density or mass density. Instead of using politropic equations of state we have solved the equations numericaly using the exact relativistic energy equation for the model of fermion gas at zero temperature. We obtain results for the mass-radius relation for white dwarfs and we compared with the results obtained using the politropic equations of state. In addition we discussed a good fit for the mass-radius relation. (paper)
Solar radius change between 1925 and 1979
Sofia, S.; Dunham, D. W.; Dunham, J. B.; Fiala, A. D.
1983-01-01
From an analysis of numerous reports from different locations on the duration of totality of the solar eclipses on January 24, 1925, and February 26, 1979, it is found that the solar radius at the earlier date was 0.5 arcsec (or 375 km) larger than at the later date. The correction to the standard solar radius found for each eclipse is different when different subsets of the observations are used (for example, edge of path of totality timings compared with central timings). This is seen as suggesting the existence of systematic inaccuracies in our knowledge of the lunar figure. The differences between the corrections for both eclipses, however, are very similar for all subsets considered, indicating that changes of the solar size may be reliably inferred despite the existence of the lunar figure errors so long as there is proper consideration of the distribution of the observations. These results are regarded as strong evidence in support of the occurrence of solar radius changes on shorter than evolutionary time scales.
Solar radius change between 1925 and 1979
International Nuclear Information System (INIS)
Sofia, S.; Fiala, A.D.
1983-01-01
By analysing numerous reports, from different locations, on the duration of totality of the solar eclipses on 24 January 1925, and on 26 February 1979, it was found that the solar radius at the earlier date was 0.5 arc s, or 375 km larger than at the later date. The correction to the standard solar radius found for each eclipse was different when different subsets of the observations were used (for example, edge of path of totality timings compared with central timings), suggesting the existence of systematic inaccuracies in our knowledge of the lunar figure. However, the differences between the corrections for both eclipses were very similar for all subsets considered, indicating that changes of the solar size may be reliably inferred despite the existence of the lunar figure errors, as long as the proper consideration is made of the distribution of the observations. It is considered that these results are strong evidence in support of the occurrence of solar radius changes on shorter than evolutionary time scales. (author)
International Nuclear Information System (INIS)
Takahashi, K.; McEntire, R.W.; Cheng, C.Z.; Kistler, L.M.
1990-01-01
The properties of 23 magnetic pulsation events observed by the AMPTE CCE spacecraft are studies. The events have a second harmonic period of 80-600 s (roughly the Pc 5 range), are observed in cluster in the dawn (0300-0800 magnetic local time, MLT) and dusk (1,600 -2,100 MLT) sectors, and are localized near the magnetic equator. Although the azimuthal wave number, m, estimated from an ion finite Larmor radius effect, is generally large (|m| ∼ 50), there is a marked difference between the events observed in the dawn and dusk sectors. In the dawn sector the waves have low frequencies (1-5 mHz), indicate right-hand polarization, and propagate westward. The authors suggest that the waves are all westward propagating in the plasma rest frame and that local-time-dependent Doppler shift is the reason for the local time dependence of the wave properties. The drift mirror instability is considered to be the mechanism for exciting the westward propagation waves. An analytical formula for the ion flux oscillations is derived on the basis of the nonlinear gyrokinetic theory. The observed correlation between the ion flux and the parallel magnetic field perturbation δB parallel can be adequately explained with this analytical formula
A measurement of the pion charge radius
International Nuclear Information System (INIS)
Amendolia, S.R.; Badelek, B.; Batignani, G.; Bedeschi, F.; Bertolucci, E.; Bettoni, D.; Bosisio, L.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giazotto, A.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Scribano, A.; Tonelli, G.; Codino, A.; Fabbri, F.L.; Laurelli, P.; Satta, L.; Spillantini, P.; Zallo, A.; Counihan, M.J.; Frank, S.G.F.; Harvey, J.; Storey, D.; Menasce, D.; Meroni, E.; Moroni, L.
1984-01-01
We report a measurement of the negative pion electromagnetic form factor in the range of space-like four-momentum transfer 0.014 2 2 . The measurement was made by the NA7 collaboration at the CERN SPS, by observing the interaction of 300 GeV pions with the electrons of a liquid hydrogen target. The form factor is fitted by a pole form with a pion radius of (rho 2 )sup(1/2) = 0.657 +- 0.012 fm. (orig.)
A measurement of the kaon charge radius
International Nuclear Information System (INIS)
Amendolia, S.R.; Batignani, G.; Bertolucci, E.; Bosisio, L.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Gianetti, P.; Giazzotto, A.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Ristori, L.; Scribano, A.; Tonelli, G.; Triggiani, G.; Beck, G.A.; Bologna, G.; D'Ettorre Piazzoli, B.; Mannocchi, G.; Picchi, P.; Budinich, M.; Liello, F.; Ragusa, F.; Rolandi, L.; Stefanini, A.; Fabbri, F.L.; Laurelli, P.; Zallo, A.; Gren, M.G.; Landon, M.P.J.; March, P.V.; Strong, J.A.; Tenchini, R.; Meroni, E.
1986-01-01
The negative kaon electromagnetic form factor has been measured in the space-like q 2 range 0.015-0.10 (GeV/c) 2 by the direct scattering of 250 GeV kaons from electrons at the CERN SPS. It is found that the kaon mean square charge radius K 2 >=0.34±0.05 fm 2 . From data collected simultaneously for πe scattering, the difference between the charged pion and kaon mean square radii (which is less sensitive to systematic errors) is found to be π 2 >- K 2 >=0.10±0.045 fm 2 . (orig.)
Small-radius jets to all orders
Cacciari, Matteo; Soyez, Gregory; Salam, Gavin; Dasgupta, Mrinal
2015-01-01
With hadron colliders continuing to push the boundaries of precision, it is becoming increas ingly important to have a detailed understanding of the subtleties appearing at smaller values of the jet radius R. We present a method to resum all leading logarithmic terms, a'.; Inn R, using a generating functional approach, as was recently discussed in Ref. 1. We study a variety of observables, such as the inclusive jet spectrum and jet vetoes for Higgs physics, and show that small-R effects can be sizeable. Finally, we compare our calculations to existing ALICE data, and show good agreement.
International Nuclear Information System (INIS)
Baumbach, S.F.; Krusche-Mandl, I.; Huf, W.; Mall, G.; Fialka, C.
2012-01-01
Purpose: The aim of the study was to investigate possible linear intra-bone geometry dependencies by determining the relation between the maximum radius length and maximum distal width in two independent populations and test for possible gender or age effects. A strong correlation can help develop more representative fracture models and osteosynthetic devices as well as aid gender and height estimation in anthropologic/forensic cases. Methods: First, maximum radius length and distal width of 100 consecutive patients, aged 20–70 years, were digitally measured on standard lower arm radiographs by two independent investigators. Second, the same measurements were performed ex vivo on a second cohort, 135 isolated, formalin fixed radii. Standard descriptive statistics as well as correlations were calculated and possible gender age influences tested for both populations separately. Results: The radiographic dataset resulted in a correlation of radius length and width of r = 0.753 (adj. R 2 = 0.563, p 2 = 0.592) and side no influence on the correlation. Radius length–width correlation for the isolated radii was r = 0.621 (adj. R 2 = 0.381, p 2 = 0.598). Conclusion: A relatively strong radius length–distal width correlation was found in two different populations, indicating that linear body proportions might not only apply to body height and axial length measurements of long bones but also to proportional dependency of bone shapes in general.
Is physics in the infinite momentum frame independent of the compactificaction radius?
International Nuclear Information System (INIS)
Gueijosa, A.
1998-01-01
With the aim of clarifying the eleven-dimensional content of matrix theory, we examine the dependence of a theory in the infinite momentum frame (IMF) on the (purely spatial) longitudinal compactification radius R. It is shown that in a point particle theory the generic scattering amplitude becomes independent of R in the IMF. Processes with zero longitudinal momentum transfer are found to be exceptional. The same question is addressed in a theory with extended objects. A one-loop type II string amplitude is shown to be R-independent in the IMF, and to coincide with that of the uncompactified theory. No exceptional processes exist in this case. The possible implications of these results for M theory are discussed. In particular, if amplitudes in M theory are independent of R in the IMF, matrix theory can be rightfully expected (in the N→∞ limit) to describe uncompactified M theory. (orig.)
On the charge radius of the neutrino
Bernabeu, J; Papavassiliou, J; Vidal, J
2000-01-01
Using the pinch technique we construct at one-loop order a neutrino charge radius, which is finite, depends neither on the gauge-fixing parameter nor on the gauge-fixing scheme employed, and is process-independent. This definition stems solely from an effective proper photon-neutrino one-loop vertex, with no reference to box or self-energy contributions. The role of the $WW$ box in this construction is critically examined. In particular it is shown that the exclusion of the effective WW box from the definition of the neutrino charge radius is not a matter of convention but is in fact dynamically realized when the target-fermions are right-handedly polarized. In this way we obtain a unique decomposition of effective self-energies, vertices, and boxes, which separately respect electroweak gauge invariance. We elaborate on the tree-level origin of the mechanism which enforces at one-loop level massive cancellations among the longitudinal momenta appearing in the Feynman diagrams, and in particular those associat...
Nuclear charge radius of {sup 11}Li
Energy Technology Data Exchange (ETDEWEB)
Sanchez, Rodolfo, E-mail: R.Sanchez@GSI.de; Noertershaeuser, Wilfried [Gesellschaft fuer Schwerionenforschung (Germany); Dax, Andreas [CERN(Switzerland); Ewald, Guido; Goette, Stefan; Kirchner, Reinhard; Kluge, H.-Juergen; Kuehl, Thomas [Gesellschaft fuer Schwerionenforschung (Germany); Wojtaszek, Agnieszka [Swietokrzyska Academy, Institute of Physics (Poland); Bushaw, Bruce A. [Pacific Northwest National Laboratory (United States); Drake, Gordon W. F. [University of Windsor, Department of Physics (Canada); Yan Zongchao [University of New Brunswick, Department of Physics (Canada); Zimmermann, Claus [Physikalisches Institut, Eberhard Karls Universitaet Tuebingen (Germany); Albers, Daniel; Behr, John; Bricault, Pierre; Dilling, Jens; Dombsky, Marik; Lassen, Jens; Phil Levy, C. D. [Tri-University Meson Facility (Canada)
2006-07-15
We have determined the nuclear charge radius of {sup 11}Li by high-precision laser spectroscopy. The experiment was performed at the TRIUMF-ISAC facility where the {sup 7}Li-{sup 11}Li isotope shift (IS) was measured in the 2s{yields}3s electronic transition using Doppler-free two-photon spectroscopy with a relative accuracy better than 10{sup -5}. The accuracy for the IS of the other lithium isotopes was also improved. IS's are mainly caused by differences in nuclear mass, but changes in proton distribution also give small contributions. Comparing experimentally measured IS with advanced atomic calculation of purely mass-based shifts, including QED and relativistic effects, allows derivation of the nuclear charge radii. The radii are found to decrease monotonically from {sup 6}Li to {sup 9}Li, and then increase with {sup 11}Li about 11% larger than {sup 9}Li. These results are a benchmark for the open question as to whether nuclear core excitation by halo neutrons is necessary to explain the large nuclear matter radius of {sup 11}Li; thus, the results are compared with a number of nuclear structure models.
International Nuclear Information System (INIS)
Sanchez, Rodolfo; Noertershaeuser, Wilfried; Dax, Andreas; Ewald, Guido; Goette, Stefan; Kirchner, Reinhard; Kluge, H.-Juergen; Kuehl, Thomas; Wojtaszek, Agnieszka; Bushaw, Bruce A.; Drake, Gordon W. F.; Yan Zongchao; Zimmermann, Claus; Albers, Daniel; Behr, John; Bricault, Pierre; Dilling, Jens; Dombsky, Marik; Lassen, Jens; Phil Levy, C. D.
2006-01-01
We have determined the nuclear charge radius of 11 Li by high-precision laser spectroscopy. The experiment was performed at the TRIUMF-ISAC facility where the 7 Li- 11 Li isotope shift (IS) was measured in the 2s → 3s electronic transition using Doppler-free two-photon spectroscopy with a relative accuracy better than 10 -5 . The accuracy for the IS of the other lithium isotopes was also improved. IS's are mainly caused by differences in nuclear mass, but changes in proton distribution also give small contributions. Comparing experimentally measured IS with advanced atomic calculation of purely mass-based shifts, including QED and relativistic effects, allows derivation of the nuclear charge radii. The radii are found to decrease monotonically from 6 Li to 9 Li, and then increase with 11 Li about 11% larger than 9 Li. These results are a benchmark for the open question as to whether nuclear core excitation by halo neutrons is necessary to explain the large nuclear matter radius of 11 Li; thus, the results are compared with a number of nuclear structure models.
Addressing the missing matter problem in galaxies through a new fundamental gravitational radius
Energy Technology Data Exchange (ETDEWEB)
Capozziello, S. [Dipartimento di Fisica ' ' E. Pancini' ' , Università di Napoli ' ' Federico II' ' , Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli (Italy); Jovanović, P. [Astronomical Observatory, Volgina 7, P.O. Box 74, 11060 Belgrade (Serbia); Jovanović, V. Borka; Borka, D., E-mail: capozziello@na.infn.it, E-mail: pjovanovic@aob.rs, E-mail: vborka@vin.bg.ac.rs, E-mail: dusborka@vin.bg.ac.rs [Atomic Physics Laboratory (040), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)
2017-06-01
We demonstrate that the existence of a Noether symmetry in f ( R ) theories of gravity gives rise to a further gravitational radius, besides the standard Schwarzschild one, determining the dynamics at galactic scales. By this feature, it is possible to explain the baryonic Tully-Fisher relation and the rotation curve of gas-rich galaxies without the dark matter hypothesis.
Research of Precataclysmic Variables with Radius Excesses
Deminova, N. R.; Shimansky, V. V.; Borisov, N. V.; Gabdeev, M. M.; Shimanskaya, N. N.
2017-06-01
The results of spectroscopic observations of the pre-cataclysmic variable NSVS 14256825, which is a HW Vir binary system, were analyzed. The chemical composition is determined, the radial velocities and equivalent widths of a given star are measured. The fundamental parameters of the components were determined (R1 = 0.166 R⊙ , M2 = 0.100 M⊙ , R2 = 0.122 R⊙). It is shown that the secondary component has a mass close to the mass of brown dwarfs. A comparison of two close binary systems is made: HS 2333 + 3927 and NSVS 14256825. A radius-to-mass relationship for the secondary components of the studied pre-cataclysmic variables is constructed. It is concluded that an excess of radii relative to model predictions for MS stars is observed in virtually all systems.
International Nuclear Information System (INIS)
Hurricane, O.A.
1994-09-01
In this dissertation, a new linear Vlasov kinetic theory is developed for calculating the plasma response to perturbing electromagnetic fields in cases where the particle dynamics are stochastic; for modes with frequencies less than the typical particle bounce frequency. A variational form is arrived at which allows one to properly perform a stability analysis for a stochastic plasma. In the case of stochastic dynamics, the authors demonstrate that the plasma responds to the flux tube volume average of the perturbing potentials as opposed to the usual case of adiabatic dynamics where plasma responds to the bounce average of the perturbed potentials. They show that for the stochastic plasma, the kinetic variational form maps into the Bernstein energy principle if the perturbation frequency is large compared to all drift frequencies, the perpendicular wavelength is large compared to the Larmor radius, and vanishing of the potentials associated with the parallel electric field are all assumed. By explicit minimization of the energy principle, it is established that the stochastic plasma is always less stable than an adiabatic plasma. Lastly, the effect of strictly enforcing the quasi-neutrality (QN) condition upon a gyro-kinetic type stability analysis is explored. From simple mathematical considerations, it is shown that when the QN condition is imposed convective type modes that are equipotentials along magnetic field lines are created that alter the stability properties of the plasma. The pertinent modifications to the Bernstein energy principle are given
The effective neutrino charge radius in the presence of fermion masses
International Nuclear Information System (INIS)
Binosi, D.; Bernabeu, J.; Papavassiliou, J.
2005-01-01
We show how the crucial gauge cancellations leading to a physical definition of an effective neutrino charge radius persist in the presence of non-vanishing fermion masses. An explicit one-loop calculation demonstrates that, as happens in the massless case, the pinch technique rearrangement of the Feynman amplitudes, together with the judicious exploitation of the fundamental current relation J α (3) =2(J Z +sinθ w 2 J γ ) α , leads to a completely gauge independent definition of the effective neutrino charge radius. Using the formalism of the Nielsen identities it is further proved that the same cancellation mechanism operates unaltered to all orders in perturbation theory
The effect of adhesion on the contact radius in atomic force microscopy indentation
International Nuclear Information System (INIS)
Sirghi, L; Rossi, F
2009-01-01
The effect of adhesion on nanoscale indentation experiments makes the interpretation of force-displacement curves acquired in these experiments very difficult. The indentation force results from the addition of adhesive and elastic forces at the indenter-sample contact. The evolution of the two forces during the indentation is determined by the variation of the indenter-sample contact radius. In the present work the variation of contact radius during atomic force microscopy (AFM) indentation of elastic and adhesive samples with conical indenters (AFM tips) is indirectly determined by measurements of the contact dynamic stiffness. For weak sample deformations, the contact radius is determined mainly by the adhesion force and indenter apex radius. For strong sample deformations, the contact radius increases linearly with the increase of the indenter displacement, the slope of this linear dependence being in agreement with Sneddon's theory of indentation (Sneddon 1965 Int. J. Eng. Sci. 3 47). Based on these results, a theoretical expression of indentation force dependence on displacement is found. This expression allows for determination of the thermodynamic work of adhesion at the indenter-sample interface and the sample elasticity modulus.
An iterative algorithm for calculating stylus radius unambiguously
International Nuclear Information System (INIS)
Vorburger, T V; Zheng, A; Renegar, T B; Song, J-F; Ma, L
2011-01-01
The stylus radius is an important specification for stylus instruments and is commonly provided by instrument manufacturers. However, it is difficult to measure the stylus radius unambiguously. Accurate profiles of the stylus tip may be obtained by profiling over an object sharper than itself, such as a razor blade. However, the stylus profile thus obtained is a partial arc, and unless the shape of the stylus tip is a perfect sphere or circle, the effective value of the radius depends on the length of the tip profile over which the radius is determined. We have developed an iterative, least squares algorithm aimed to determine the effective least squares stylus radius unambiguously. So far, the algorithm converges to reasonable results for the least squares stylus radius. We suggest that the algorithm be considered for adoption in documentary standards describing the properties of stylus instruments.
Numerical Radius Inequalities for Finite Sums of Operators
Directory of Open Access Journals (Sweden)
Mirmostafaee Alireza Kamel
2014-12-01
Full Text Available In this paper, we obtain some sharp inequalities for numerical radius of finite sums of operators. Moreover, we give some applications of our result in estimation of spectral radius. We also compare our results with some known results.
International Nuclear Information System (INIS)
Bendali, N.; Duong, H.T.; Saint-Jalm, J.M.; Vialle, J.L.
1984-01-01
Measurement of nuclear spin in the collinear laser spectroscopy method has been investigated using a fast sodium atomic beam excited collinearly by a C.W. single mode dye laser beam. The atomic magnetic moments are first aligned by optical pumping process, then they interact with a static magnetic field H 0 . The magnetic alignment of the atomic system just at the exit of the magnetic field is monitored by the laser induced fluorescence. Upon varying the amplitude of H 0 , the fluorescence signal presents a fringed structure. This structure is due to the Larmor precession of the aligned magnetic moments around H 0 , and therefore it is a signature of the spin involved. The modulation patterns corresponding to different relative orientations of H 0 and light polarization direction, are fitted by an analytical formula. In a second step, a classical magnetic resonance experiment with a static magnetic field and a radiofrequency field has been performed. The monocinetic character of our fast atomic beam allowed us to observe, even at high r.f. power, resonances line shapes in agreement with the Majorana formula
MUSE: Measuring the proton radius with muon-proton scattering
Energy Technology Data Exchange (ETDEWEB)
Bernauer, Jan Christopher [Massachusetts Institute of Technology, Cambridge (United States)
2014-07-01
The proton radius has been measured so far using electron-proton scattering, electronic Hydrogen spectroscopy and muonic Hydrogen spectroscopy, the latter producing a much more accurate, but seven sigma different, result, leading to the now famous proton radius puzzle. The MUSE collaboration aims to complete the set of measurements by using muon scattering to determine the proton radius and to shed light on possible explanations of the discrepancy. The talk gives an overview of the experiment motivation and design and a status report on the progress.
Variational principles for the spectral radius of functional operators
International Nuclear Information System (INIS)
Antonevich, A B; Zajkowski, K
2006-01-01
The spectral radius of a functional operator with positive coefficients generated by a set of maps (a dynamical system) is shown to be a logarithmically convex functional of the logarithms of the coefficients. This yields the following variational principle: the logarithm of the spectral radius is the Legendre transform of a convex functional T defined on a set of vector-valued probability measures and depending only on the original dynamical system. A combinatorial construction of the functional T by means of the random walk process corresponding to the dynamical system is presented in the subexponential case. Examples of the explicit calculation of the functional T and the spectral radius are presented.
Correlation between quarter-point angle and nuclear radius
Ma, Wei-Hu; Wang, Jian-Song; Mukherjee, S.; Wang, Qi; Patel, D.; Yang, Yan-Yun; Ma, Jun-Bing; Ma, Peng; Jin, Shi-Lun; Bai, Zhen; Liu, Xing-Quan
2017-04-01
The correlation between quarter-point angle of elastic scattering and nuclear matter radius is studied systematically. Various phenomenological formulae with parameters for nuclear radius are adopted and compared by fitting the experimental data of quarter point angle extracted from nuclear elastic scattering reaction systems. A parameterized formula related to binding energy is recommended, which gives a good reproduction of nuclear matter radii of halo nuclei. It indicates that the quarter-point angle of elastic scattering is quite sensitive to the nuclear matter radius and can be used to extract the nuclear matter radius. Supported by National Natural Science Foundation of China (U1432247, 11575256), National Basic Research Program of China (973 Program)(2014CB845405 and 2013CB83440x) and (SM) Chinese Academy of Sciences President’s International Fellowship Initiative (2015-FX-04)
Spectroscopy of muonic atoms and the proton radius puzzle
Antognini, Aldo
2017-09-01
We have measured several 2 S -2 P transitions in muonic hydrogen (μp), muonic deuterium (μd) and muonic helium ions (μ3He, μ4He). From muonic hydrogen we extracted a proton charge radius 20 times more precise than obtained from electron-proton scattering and hydrogen high-precision laser spectroscopy but at a variance of 7 σ from these values. This discrepancy is nowadays referred to as the proton radius puzzle. New insight has been recently provided by the first determination of the deuteron charge radius from laser spectroscopy of μd. The status of the proton charge radius puzzle including the new insights obtained by μd spectroscopy will be discussed. Work supported by the Swiss National Science Foundation SNF-200021-165854 and the ERC CoG. #725039.
Human Fertility Increases with the Marital-radius
DEFF Research Database (Denmark)
Labouriau, Rodrigo; Amorim, António
2008-01-01
We report a positive association between marital radius (distance between mates' birthplaces) and fertility detected in a large population. Spurious association due to socioeconomic factors is discarded by a conditional analysis involving income, education, and urbanicity. Strong evidence...
Frictional coefficient depending on active friction radius with BPV ...
African Journals Online (AJOL)
Frictional coefficient depending on active friction radius with BPV and BTV in automobile disc braking system. ... International Journal of Engineering, Science and Technology. Journal Home · ABOUT ... AJOL African Journals Online. HOW TO ...
DML and Foil Measurements of ETA Beam Radius
International Nuclear Information System (INIS)
Nexsen, W; Weir, J
2005-01-01
Simultaneous measurements of the ETA beam radius have been made with a quartz foil and a diamagnetic loop (DML). While the measurements agreed at some settings they diverged at others. While the DML measures the rms radius of the total beam, the foil measures mainly the core and the divergence can be explained by the presence of a low density halo. Evidence of such a halo from other measurements is presented
Generalized spectral radius and its max algebra version
Czech Academy of Sciences Publication Activity Database
Müller, Vladimír; Peperko, A.
2013-01-01
Roč. 439, č. 4 (2013), s. 1006-1016 ISSN 0024-3795 R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional support: RVO:67985840 Keywords : generalized spectral radius * joint spectral radius * Berger-Wang formula Subject RIV: BA - General Mathematics Impact factor: 0.983, year: 2013 http://www.sciencedirect.com/science/article/pii/S0024379512007380
Energy Technology Data Exchange (ETDEWEB)
Zhang, X., E-mail: Xuan.Zhang@candu.com [Candu Energy Inc, Mississauga, ON (Canada)
2015-07-01
A curved pipe element, ELBOW290, became available in ANSYS 12. This element was developed based on a simplified shell theory, and maintains the ability to capture cross-sectional deformations of elbows. Numerical testing on the applicability of this element for the flexibility calculation of the tight radius bends in CANDU reactors is carried out to determine the usability of this element in completing stress analyses for feeder pipes. Comparisons are made between the ELBOW290 and the shell element for various feeder bend types found in domestic and overseas CANDU reactors. The comparisons show that the ELBOW290 element is suitable for calculating the flexibility of the tight radius bends. (author)
Jet launching radius in low-power radio-loud AGNs in advection-dominated accretion flows
Le, Truong; Newman, William; Edge, Brinkley
2018-06-01
Using our theory for the production of relativistic outflows, we estimate the jet launching radius and the inferred mass accretion rate for 52 low-power radio-loud AGNs based on the observed jet powers. Our analysis indicates that (1) a significant fraction of the accreted energy is required to convert the accreted mass to relativistic energy particles for the production of the jets near the event horizon, (2) the jet's launching radius moves radially towards the horizon as the mass accretion rate or jet's power increases, and (3) no jet/outflow formation is possible beyond 44 gravitational radii.
The geometry of Larmor nutation
Indian Academy of Sciences (India)
It is shown that, in this frame, the nutating vector generates, in general, what may be called interpenetrating partial cones, the two parts of which merge into a single cone traced twice over, when the orbit of the charged particle changes to a circle – giving an immediate explanation of the discontinuous jump in the nutation ...
On tidal radius determination for a globular cluster
International Nuclear Information System (INIS)
Ninkovic, S.
1985-01-01
A tidal radius determination for a globular cluster based on its density minimum, which is caused by the galactic tidal forces and derivable from a model of the Galaxy, is proposed. Results obtained on the basis of the Schmidt model for two clusters are in a satisfactory agreement with those obtained earlier by means of other methods. A mass determination for the clusters through the tidal radius, when the latter one is identified with the cluster perigalactic distance, yields unusually large mass values. Probably, the tidal radius should be identified with the instantaneous galactocentric distance. Use of models more recent than the Schmidt one indicates that a globular cluster may contain a significant portion of an invisible interstellar matter. (author)
Rational functions with maximal radius of absolute monotonicity
Loczi, Lajos
2014-05-19
We study the radius of absolute monotonicity R of rational functions with numerator and denominator of degree s that approximate the exponential function to order p. Such functions arise in the application of implicit s-stage, order p Runge-Kutta methods for initial value problems and the radius of absolute monotonicity governs the numerical preservation of properties like positivity and maximum-norm contractivity. We construct a function with p=2 and R>2s, disproving a conjecture of van de Griend and Kraaijevanger. We determine the maximum attainable radius for functions in several one-parameter families of rational functions. Moreover, we prove earlier conjectured optimal radii in some families with 2 or 3 parameters via uniqueness arguments for systems of polynomial inequalities. Our results also prove the optimality of some strong stability preserving implicit and singly diagonally implicit Runge-Kutta methods. Whereas previous results in this area were primarily numerical, we give all constants as exact algebraic numbers.
Measurements of Physical Parameters of White Dwarfs: A Test of the Mass–Radius Relation
Energy Technology Data Exchange (ETDEWEB)
Bédard, A.; Bergeron, P.; Fontaine, G., E-mail: bedard@astro.umontreal.ca, E-mail: bergeron@astro.umontreal.ca, E-mail: fontaine@astro.umontreal.ca [Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec H3C 3J7 (Canada)
2017-10-10
We present a detailed spectroscopic and photometric analysis of 219 DA and DB white dwarfs for which trigonometric parallax measurements are available. Our aim is to compare the physical parameters derived from the spectroscopic and photometric techniques, and then to test the theoretical mass–radius relation for white dwarfs using these results. The agreement between spectroscopic and photometric parameters is found to be excellent, especially for effective temperatures, showing that our model atmospheres and fitting procedures provide an accurate, internally consistent analysis. The values of surface gravity and solid angle obtained, respectively, from spectroscopy and photometry, are combined with parallax measurements in various ways to study the validity of the mass–radius relation from an empirical point of view. After a thorough examination of our results, we find that 73% and 92% of the white dwarfs are consistent within 1 σ and 2 σ confidence levels, respectively, with the predictions of the mass–radius relation, thus providing strong support to the theory of stellar degeneracy. Our analysis also allows us to identify 15 stars that are better interpreted in terms of unresolved double degenerate binaries. Atmospheric parameters for both components in these binary systems are obtained using a novel approach. We further identify a few white dwarfs that are possibly composed of an iron core rather than a carbon/oxygen core, since they are consistent with Fe-core evolutionary models.
Sectio Aurea Conditions for Mityuk's Radius of Two-Connected Domains
Directory of Open Access Journals (Sweden)
A.V. Kazantsev
2017-03-01
Full Text Available Connection of an exterior inverse boundary value problem with the critical points of some surface is one of the central themes in the theory of exterior inverse boundary value problems for analytic functions. In the simply connected case, such a surface is defined by the inner mapping radius; in the multiply connected one, by the function Ω(w such that M(w = (2π–1ln Ω(w is Mityuk's version of a generalized reduced module. In the present paper, the relation between the curvature of the surface Ω = Ω(w with the Schwarzian derivatives of the mapping functions and with the Bergman kernel functions k0(w,ω and l0(w,ω is established for an arbitrary multiply connected domain. When passing to two-connected domains, due to the choice of the ring as a canonical domain, we construct the conditions for the critical points of Mityuk's radius to concentrate on the golden section circle of the ring. Finally, we show that the minimal collection of the critical points of the Mityuk radius in the two-connected case, consisting of one maximum and one saddle, is attained for the linear-fractional solution of the exterior inverse boundary value problem.
Dependence of yield of nuclear track-biosensors on track radius and analyte concentration
García-Arellano, H.; Muñoz H., G.; Fink, D.; Vacik, J.; Hnatowicz, V.; Alfonta, L.; Kiv, A.
2018-04-01
In swift heavy ion track-based polymeric biosensor foils with incorporated enzymes one exploits the correlation between the analyte concentration and the sensor current, via the enrichment of charged enzymatic reaction products in the track's confinement. Here we study the influence of the etched track radius on the biosensor's efficiency. These sensors are analyte-specific only if both the track radii and the analyte concentration exceed certain threshold values of ∼15 nm and ∼10-6 M (for glucose sensing), respectively. Below these limits the sensor signal stems un-specifically from any charge carrier. In its proper working regime, the inner track walls are smoothly covered by enzymes and the efficiency is practically radius independent. Theory shows that the measured current should be slightly sub-proportional to the analyte concentration; the measurements roughly reconfirm this. Narrower tracks (∼5-15 nm radius) with reduced enzyme coverage lead to decreasing efficiency. Tiny signals visible when the tracks are etched to effective radii between 0 and ∼5 nm are tentatively ascribed to enzymes bonded to surface-near nano-cracks in the polymer foil, resulting from its degradation due to aging, rather than to the tracks. Precondition for this study was the accurate determination of the etched track radii, which is possible only by a nanofluidic approach. This holds to some extent even for enzyme-covered tracks, though in this case most of the wall charges are compensated by enzyme bonding.
Theoretical distribution of load in the radius and ulna carpal joint.
Márquez-Florez, Kalenia; Vergara-Amador, Enrique; de Las Casas, Estevam Barbosa; Garzón-Alvarado, Diego A
2015-05-01
The purpose of this study is to validate a model for the analysis of the load distribution through the wrist joint, subjected to forces on the axes of the metacarpals from distal to proximal for two different mesh densities. To this end, the Rigid Body Spring Model (RBSM) method was used on a three-dimensional model of the wrist joint, simulating the conditions when making a grip handle. The cartilage and ligaments were simulated as springs acting under compression and tension, respectively, while the bones were considered as rigid bodies. At the proximal end of the ulna the movement was completely restricted, and the radius was allowed to move only in the lateral/medial direction. With these models, we found the load distributions on each carpal articular surface of radius. Additionally, the results show that the percentage of the applied load transmitted through the radius was about 86% for one mesh and 88% for the coarser one; for the ulna it was 21% for one mesh and 18% for the coarser. The obtained results are comparable with previous outcomes reported in prior studies. The latter allows concluding that, in theory, the methodology can be used to describe the changes in load distribution in the wrist. Copyright © 2015 Elsevier Ltd. All rights reserved.
Threshold and jet radius joint resummation for single-inclusive jet production
Energy Technology Data Exchange (ETDEWEB)
Liu, Xiaohui [Beijing Normal Univ. (China). Center of Advanced Quantum Studies; Moch, Sven-Olaf [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Ringer, Felix [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Nuclear Science Division
2017-08-15
We present the first threshold and jet radius jointly resummed cross section for single-inclusive hadronic jet production. We work at next-to-leading logarithmic accuracy and our framework allows for a systematic extension beyond the currently achieved precision. Longstanding numerical issues are overcome by performing the resummation directly in momentum space within Soft Collinear Effective Theory. We present the first numerical results for the LHC and observe an improved description of the available data. Our results are of immediate relevance for LHC precision phenomenology including the extraction of parton distribution functions and the QCD strong coupling constant.
The hadronic corrections to muonic hydrogen Lamb shift from ChPT and the proton radius
Energy Technology Data Exchange (ETDEWEB)
Peset, Clara [Grup de Física Teòrica, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)
2016-01-22
We obtain a model independent expression for the muonic hydrogen Lamb shift. The leading hadronic effects are controlled by the chiral theory, which allows for their model independent determination. We give their complete expression including the pion and Delta particles. Out of this analysis and the experimental measurement of the muonic hydrogen Lamb shift we determine the electromagnetic proton radius: r{sub p} = 0.8412(15) fm. This number is at 6.8σ variance with respect to the CODATA value. The parametric control of the uncertainties allows us to obtain a model independent determination of the error, which is dominated by hadronic effects.
Thoughts on the so-called 'radius-capitellum axis'
International Nuclear Information System (INIS)
Schild, H.; Mueller, H.A.; Wagner, H.; Baetz, W.; Mainz Univ.
1982-01-01
We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull. (orig.) [de
Thoughts on the so-called radius-capitellum axis
Energy Technology Data Exchange (ETDEWEB)
Schild, H; Mueller, H A; Wagner, H; Baetz, W
1982-02-01
We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull.
The PRad experiment and the proton radius puzzle
Directory of Open Access Journals (Sweden)
Gasparian Ashot
2014-06-01
Full Text Available New results from the recent muonic hydrogen experiments seriously questioned our knowledge of the proton charge radius, rp. The new value, with its unprecedented less than sub-percent precision, is currently up to eight standard deviation smaller than the average value from all previous experiments, triggering the well-known “proton charge radius puzzle” in nuclear and atomic physics. The PRad collaboration is currently preparing a novel, magnetic-spectrometer-free ep scattering experiment in Hall B at JLab for a new independent rp measurement to address this growing “puzzle” in physics.
Underground nuclear explosions. Study of the cavity radius
International Nuclear Information System (INIS)
Michaud, L.
1968-11-01
An underground nuclear explosion creates a cavity due to the expansion of the surrounding medium vaporized by the shot. The cavity radius is related to the energy of explosion and to the overburden pressure of the medium. The introduction of new elements such as the environment of the device (in a deep hole or in a tunnel) and the cohesion of the medium leads to a relationship which determines this radius. The known French and American underground explosions performed in various media, energy and overburden conditions, satisfy this relationship with a good precision. (author) [fr
International Nuclear Information System (INIS)
Castejon M, F.
1989-01-01
The study of the Linear Theory microwave propagation and absorption in the the frequency range of electron cyclotron resonance, in a magnetized plasma, is developed. This study is particularized to the flexible heliac TJ-II, whose main characteristics are dsetailed in a memory chapter, as an interesting case example for its peculiar magnetic configuration. As a preliminary phase, a cold plasma model is useds to analyze the resonance accessibility and the approximated density limits which will be obtainable in each electron cyclotron resonance harmonic. This analysis was used to find the suitable positions for the microwave injection in TJ-II. An analytical weakly relativistic model for the dielectric tensor is developed, valid for oblique propagation, that takes account of the effect of superthermal electrons. Second order Larmor radius effects are included, so that the Quasi-Electrostatic branch of X mode can be studied. A numerical study is then presented on the absorption properties of TJ-II. Since the TJ-II geometry is complex and its magnetic field distribution is very different from that of a tokamak, ray tracing calculations are necessary to consider refraction effects. The ray tracing codse RAYS, developed in the Oak Ridge National Laboratory (U.S.A.), was take and adapted to the helical magnetic configuration of the TJ-II. The absorption model described above was then included in RAYS. For completeness, an introduction to the Quasi Linear Theory, natural prolongation of this work, is included at the end of the memory, ands the effects of taking into account the quasi linear evolution of the distribution function are described. (Author)
Acceleration of beam ions during major radius compression in TFTR
International Nuclear Information System (INIS)
Wong, K.L.; Bitter, M.; Hammett, G.W.
1985-09-01
Tangentially co-injected deuterium beam ions were accelerated from 82 keV up to 150 keV during a major radius compression experiment in TFTR. The ion energy spectra and the variation in fusion yield were in good agreement with Fokker-Planck code simulations. In addition, the plasma rotation velocity was observed to rise during compression
Coulomb corrections to scattering length and effective radius
International Nuclear Information System (INIS)
Mur, V.D.; Kudryavtsev, A.E.; Popov, V.S.
1983-01-01
The problem considered is extraction of the ''purely nuclear'' scattering length asub(s) (corresponding to the strong potential Vsub(s) at the Coulomb interaction switched off) from the Coulomb-nuclear scattering length asub(cs), which is an object of experimental measurement. The difference between asub(s) and asub(cs) is especially large if the potential Vsub(s) has a level (real or virtual) with an energy close to zero. For this case formulae are obtained relating the scattering lengths asub(s) and asub(cs), as well as the effective radii rsub(s) and rsub(cs). The results are extended to states with arbitrary angular momenta l. It is shown that the Coulomb correction is especially large for the coefficient with ksup(2l) in the expansion of the effective radius; in this case the correction contains a large logarithm ln(asub(B)/rsub(0)). The Coulomb renormalization of other terms in the effective radius espansion is of order (rsub(0)/asub(B)), where r 0 is the nuclear force radius, asub(B) is the Bohr radius. The obtained formulae are tried on a number of model potentials Vsub(s), used in nuclear physics
Radius ratio effects on natural heat transfer in concentric annulus
DEFF Research Database (Denmark)
Alipour, M.; Hosseini, R.; Kolaei, Alireza Rezania
2013-01-01
This paper studies natural convection heat transfer in vertical and electrically heated annulus. The metallic cylinders mounted concentrically in a parallel tube. Measurements are carried out for four input electric powers and three radius ratios with an apparatus immersed in stagnant air...
Social Support Contributes to Outcomes following Distal Radius Fractures
Directory of Open Access Journals (Sweden)
Caitlin J. Symonette
2013-01-01
Full Text Available Background. Distal radius fractures are the most common fracture of the upper extremity and cause variable disability. This study examined the role of social support in patient-reported pain and disability at one year following distal radius fracture. Methods. The Medical Outcomes Study Social Support Survey was administered to a prospective cohort of 291 subjects with distal radius fractures at their baseline visit. Pearson correlations and stepwise linear regression models (F-to-remove 0.10 were used to identify whether social support contributes to wrist fracture outcomes. The primary outcome of pain and disability at one year was measured using the Patient Rated Wrist Evaluation. Results. Most injuries were low energy (67.5% and were treated nonoperatively (71.9%. Pearson correlation analysis revealed that higher reported social support correlated with improved Patient Rated Wrist Evaluation scores at 1 year, r(n=181=-0.22, P<0.05. Of the subscales within the Social Support Survey, emotional/informational support explained a significant proportion of the variance in 1-year Patient Rated Wrist Evaluation scores, R2=4.7%, F (1, 181 = 9.98, P<0.05. Conclusion. Lower emotional/informational social support at the time of distal radius fracture contributes a small but significant percentage to patient-reported pain and disability outcomes.
Axial Length/Corneal Radius of Curvature Ratio and Refractive ...
African Journals Online (AJOL)
2017-12-05
Dec 5, 2017 ... variously described as determined by the ocular biometric variables. There have been many studies on the relationship between refractive error and ocular axial length (AL), anterior chamber depth, corneal radius of curvature (CR), keratometric readings as well as other ocular biometric variables such as ...
Rational functions with maximal radius of absolute monotonicity
Loczi, Lajos; Ketcheson, David I.
2014-01-01
-Kutta methods for initial value problems and the radius of absolute monotonicity governs the numerical preservation of properties like positivity and maximum-norm contractivity. We construct a function with p=2 and R>2s, disproving a conjecture of van de Griend
Thrombocytopenia-absent radius syndrome: a clinical genetic study.
Greenhalgh, K.L.; Howell, R.; Bottani, A.; Ancliff, P.J.; Brunner, H.G.; Verschuuren-Bemelmans, C.C.; Vernon, E.; Brown, K.W.; Newbury-Ecob, R.
2002-01-01
The thrombocytopenia-absent radius (TAR) syndrome is a congenital malformation syndrome characterised by bilateral absence of the radii and a thrombocytopenia. The lower limbs, gastrointestinal, cardiovascular, and other systems may also be involved. Shaw and Oliver in 1959 were the first to
Thrombocytopenia-absent radius syndrome : a clinical genetic study
Greenhalgh, KL; Howell, RT; Bottani, A; Ancliff, PJ; Brunner, HG; Verschuuren-Bemelmans, CC; Vernon, E; Brown, KW; Newbury-Ecob, RA
2002-01-01
The thrombocytopenia-absent radius (TAR) syndrome is a congenital malformation syndrome characterised by bilateral absence of the radii and a thrombocytopenia. The lower limbs, gastrointestinal, cardiovascular, and other systems may also be involved. Shaw and Oliver in 1959 were the first to
Individualist-Collectivist Culture and Trust Radius : A Multilevel Approach
van Hoorn, André
We apply a multilevel approach to examine empirically the nexus between individualist and collectivist culture on the one hand and people’s radius of trust on the other. People’s trust level (i.e., the intensity with which people trust other people) has been extensively studied. Increasingly,
Ultrasonic pattern recognition study of feedwater nozzle inner radius indication
International Nuclear Information System (INIS)
Yoneyama, H.; Takama, S.; Kishigami, M.; Sasahara, T.; Ando, H.
1983-01-01
A study was made to distinguish defects on feed-water nozzle inner radius from noise echo caused by stainless steel cladding by using ultrasonic pattern recognition method with frequency analysis technique. Experiment has been successfully performed on flat clad plates and nozzle mock-up containing fatigue cracks and the following results which shows the high capability of frequency analysis technique are obtained
Study of a pulsed capillary discharge with a modulated radius
Broks, B.H.P.; Dijk, van W.; Mullen, van der J.J.A.M.; Veldhuizen, van E.M.
2005-01-01
In this contribution, we present a plasma physical model of a pulsed capillary discharge with a modulated radius. Using a 2D time-dependent model, we have modeled the plasma and wall properties of this channel. It was found that properties of the central plasma are different than the properties of a
Recognizing chaotic states in stadium billiard by calculating gyration radius
Directory of Open Access Journals (Sweden)
M. Barezi
2006-12-01
Full Text Available Nowadays study of chaotic quantum billiards because of their relation to Nano technology. In this paper distribution of zeros of wave function on the boundary of two circular and stadium billiards are investigated. By calculating gyration radius for these points chaotic and non-chaotic states are distinguished.
21 CFR 886.1450 - Corneal radius measuring device.
2010-04-01
... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Corneal radius measuring device. 886.1450 Section 886.1450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... corneal size by superimposing the image of the cornea on a scale at the focal length of the lens of a...
Artificial gravity: head movements during short-radius centrifugation
Young, L. R.; Hecht, H.; Lyne, L. E.; Sienko, K. H.; Cheung, C. C.; Kavelaars, J.
2001-01-01
Short-radius centrifugation is a potential countermeasure to long-term weightlessness. Unfortunately, head movements in a rotating environment induce serious discomfort, non-compensatory vestibulo-ocular reflexes, and subjective illusions of body tilt. In two experiments we investigated the effects
The Compton Radius, the de Broglie Radius, the Planck Constant, and the Bohr Orbits
Directory of Open Access Journals (Sweden)
Daywitt W. C.
2011-04-01
Full Text Available The Bohr orbits of the hydrogen atom and the Planck constant can be derived classically from the Maxwell equations and the assumption that there is a variation in the electron's velocity about its average value. The resonant nature of the circulating electron and its induced magnetic and Faraday fields prevents a radiative collapse of the electron into the nuclear proton. The derived Planck constant is $h=2pi e^2/alpha c$, where $e$, $alpha$, and $c$ are the electronic charge, the fine structure constant, and the speed of light. The fact that the Planck vacuum (PV theory derives the same Planck constant independently of the above implies that the two derivations are related. The following highlights that connection.
The Compton Radius, the de Broglie Radius, the Planck Constant, and the Bohr Orbits
Directory of Open Access Journals (Sweden)
Daywitt W. C.
2011-04-01
Full Text Available The Bohr orbits of the hydrogen atom and the Planck constant can be derived classically from the Maxwell equations and the assumption that there is a variation in the electron’s velocity about its average value [1]. The resonant nature of the circulating electron and its induced magnetic and Faraday fields prevents a radiative collapse of the electron into the nuclear proton. The derived Planck constant is h = 2 e 2 = c , where e , , and c are the electronic charge, the fine structure constant, and the speed of light. The fact that the Planck vacuum (PV theory [2] derives the same Planck constant independently of the above implies that the two derivations are related. The following highlights that connection.
Influence of asymmetrical drawing radius deviation in micro deep drawing
Heinrich, L.; Kobayashi, H.; Shimizu, T.; Yang, M.; Vollertsen, F.
2017-09-01
Nowadays, an increasing demand for small metal parts in electronic and automotive industries can be observed. Deep drawing is a well-suited technology for the production of such parts due to its excellent qualities for mass production. However, the downscaling of the forming process leads to new challenges in tooling and process design, such as high relative deviation of tool geometry or blank displacement compared to the macro scale. FEM simulation has been a widely-used tool to investigate the influence of symmetrical process deviations as for instance a global variance of the drawing radius. This study shows a different approach that allows to determine the impact of asymmetrical process deviations on micro deep drawing. In this particular case the impact of an asymmetrical drawing radius deviation and blank displacement on cup geometry deviation was investigated for different drawing ratios by experiments and FEM simulation. It was found that both variations result in an increasing cup height deviation. Nevertheless, with increasing drawing ratio a constant drawing radius deviation has an increasing impact, while blank displacement results in a decreasing offset of the cups geometry. This is explained by different mechanisms that result in an uneven cup geometry. While blank displacement leads to material surplus on one side of the cup, an unsymmetrical radius deviation on the other hand generates uneven stretching of the cups wall. This is intensified for higher drawing ratios. It can be concluded that the effect of uneven radius geometry proves to be of major importance for the production of accurately shaped micro cups and cannot be compensated by intentional blank displacement.
Variable radius cartography - History and perspectives of a new discipline
Scalera, Giancarlo
2014-05-01
The map that Toscanelli sent to Columbus was an unconscious application of cartography at a smaller radius than the real. The first really conscious attempts to represent the geography of Earth on globes of radius less than the current one occurred after the formulation of the concept of expanding Earth through geological time. The American chemist and geologist Richard Owen (1810-1890) in his book Key to the geology of the globe (1857) described the principles of what he himself called Anatomical Geology, with the Earth growing as a biological organism. The book contained a global paleogeographic map of the Earth that would have had a radius of about 4000 kilometers. In 1928 J.A.H. Kerkhoff (under the pseudonym Aero-dilettant) published a series of paleogeographic globes on which the modern oceans disappeared. With the same artisan methods of transfer continental outlines from a sphere to a smaller one, in 1933 O.C. Hilgenberg represented three different geological epochs, and, later, for the first time mapped paleopoles with their site-pole segments of meridian. Even today the traditional method of Hilgenberg is followed by senior researchers (Klaus Vogel, 2003) and younger geologists (James Maxlow). In England Hugh Owen applied the methods of traditional cartography to the variable radius one. His Atlas of Continental Displacement was in the 70s and 80s, for this discipline, a real milestone. While in the field of constant radius paleogeography the adherents to plate tectonics created many computer codes of automatic mapping (Bullard et al., 1965; Smith & Hallam, 1970; Scotese et al., 1979; and many others), in the variable radius field few tried to reach the same task. In 1972 in United States a first very simple attempt (but was not further developed) came from a private, R.B. Perry, followed by the still not-computerized Atlas of Owen, and both them constituted inspiration for the construction of a FORTRAN variable radius mapping code at INGV, with which it
The deuteron-radius puzzle is alive: A new analysis of nuclear structure uncertainties
Hernandez, O. J.; Ekström, A.; Nevo Dinur, N.; Ji, C.; Bacca, S.; Barnea, N.
2018-03-01
To shed light on the deuteron radius puzzle we analyze the theoretical uncertainties of the nuclear structure corrections to the Lamb shift in muonic deuterium. We find that the discrepancy between the calculated two-photon exchange correction and the corresponding experimentally inferred value by Pohl et al. [1] remain. The present result is consistent with our previous estimate, although the discrepancy is reduced from 2.6 σ to about 2 σ. The error analysis includes statistic as well as systematic uncertainties stemming from the use of nucleon-nucleon interactions derived from chiral effective field theory at various orders. We therefore conclude that nuclear theory uncertainty is more likely not the source of the discrepancy.
Influences on the radius of the auroral oval
Directory of Open Access Journals (Sweden)
S. E. Milan
2009-07-01
Full Text Available We examine the variation in the radius of the auroral oval, as measured from auroral images gathered by the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE spacecraft, in response to solar wind inputs measured by the Advanced Composition Explorer (ACE spacecraft for the two year interval June 2000 to May 2002. Our main finding is that the oval radius increases when the ring current, as measured by the Sym-H index, is intensified during geomagnetic storms. We discuss our findings within the context of the expanding/contracting polar cap paradigm, in terms of a modification of substorm onset conditions by the magnetic perturbation associated with the ring current.
Local Convergence and Radius of Convergence for Modified Newton Method
Directory of Open Access Journals (Sweden)
Măruşter Ştefan
2017-12-01
Full Text Available We investigate the local convergence of modified Newton method, i.e., the classical Newton method in which the derivative is periodically re-evaluated. Based on the convergence properties of Picard iteration for demicontractive mappings, we give an algorithm to estimate the local radius of convergence for considered method. Numerical experiments show that the proposed algorithm gives estimated radii which are very close to or even equal with the best ones.
Factors Associated with Infection Following Open Distal Radius Fractures
Glueck, Dane A.; Charoglu, Constantine P.; Lawton, Jeffrey N.
2009-01-01
Open fractures are often classified according to a system described by Gustilo and Anderson. However, this system was applied to open long bone factures, which may not predict the incidence of infection in open metaphyseal fractures of the upper extremity. Other studies have found that wound contamination and systemic illness were the best predictors of infections in open hand fractures. Our study assessed infection in open distal radius fractures and identifies factors that are associated wi...
Fractures of the shafts of the radius and ulna
International Nuclear Information System (INIS)
Bender, C.E.; Campbell, D.C.
1985-01-01
Although the clinical presentation of fracture of the forearm bones is usually quite obvious, thorough radiologic examination of the radius and ulna and adjacent wrist and elbow joints is mandatory. Standard views of the forearm of the patient include the AP and lateral projections. The degree of shortening, angulation, rotation, and comminution should be noted. The selected films must be long enough to include the adjacent elbow and wrist joints
THE SIZE-VIRIAL RADIUS RELATION OF GALAXIES
International Nuclear Information System (INIS)
Kravtsov, Andrey V.
2013-01-01
I use the abundance matching ansatz, which has proven to be successful in reproducing galaxy clustering and other statistics, to derive estimates of the virial radius, R 200 , for galaxies of different morphological types and a wide range of stellar masses. I show that over eight orders of magnitude in stellar mass galaxies of all morphological types follow an approximately linear relation between half-mass radius of their stellar distribution, r 1/2 , and virial radius, r 1/2 ≈ 0.015 R 200 , with scatter of ≈0.2 dex. Such scaling is in remarkable agreement with the expectation of models that assume that galaxy sizes are controlled by halo angular momentum, r 1/2 ∝λR 200 , where λ is the spin of galaxy parent halo. The scatter about the relation is comparable with the scatter expected from the distribution of λ. Moreover, I show that when the stellar and gas surface density profiles of galaxies of different morphological types are rescaled by the radius r n = 0.015 R 200 , the rescaled profiles follow approximately universal exponential (for late types) and de Vaucouleurs (for early types) form with scatter of only ≈30%-50% at R ≈ 1-3r n . Remarkably, both late- and early-type galaxies have similar mean stellar surface density profiles at R ∼> 1r n . The main difference between their stellar distributions is thus at R n . The results of this study imply that galaxy sizes and radial distribution of baryons are shaped primarily by properties of their parent halos and that the sizes of both late-type disks and early-type spheroids are controlled by halo angular momentum.
Localized electronic states: the small radius potential approximation
International Nuclear Information System (INIS)
Steslicka, M.; Jurczyszyn, L.
1984-09-01
Using a quasi three-dimensional crystal model we investigate the localized electronic states, generated by the crystal surface covered by foreign atoms. Two such states are found in the first forbidden energy gap and, because of their localization properties, called the Tamm-like and adsorption-like states. Using the small radius potential approximation, the properties of both types of states were discussed in detail. (author)
Neutron charge radius and the neutron electric form factor
International Nuclear Information System (INIS)
Gentile, T. R.; Crawford, C. B.
2011-01-01
For nearly forty years, the Galster parametrization has been employed to fit existing data for the neutron electric form factor, G E n , vs the square of the four-momentum transfer, Q 2 . Typically this parametrization is constrained to be consistent with experimental data for the neutron charge radius. However, we find that the Galster form does not have sufficient freedom to accommodate reasonable values of the radius without constraining or compromising the fit. In addition, the G E n data are now at sufficient precision to motivate a two-parameter fit (or three parameters if we include thermal neutron data). Here we present a modified form of a two-dipole parametrization that allows this freedom and fits both G E n (including recent data at both low and high four-momentum transfer) and the charge radius well with simple, well-defined parameters. Analysis reveals that the Galster form is essentially a two-parameter approximation to the two-dipole form but becomes degenerate if we try to extend it naturally to three parameters.
Is the proton radius puzzle evidence of extra dimensions?
Energy Technology Data Exchange (ETDEWEB)
Dahia, F.; Lemos, A.S. [Universidade Federal da Paraiba, Department of Physics, Joao Pessoa, PB (Brazil)
2016-08-15
The proton charge radius inferred from muonic hydrogen spectroscopy is not compatible with the previous value given by CODATA-2010, which, on its turn, essentially relies on measurements of the electron-proton interaction. The proton's new size was extracted from the 2S-2P Lamb shift in the muonic hydrogen, which showed an energy excess of 0.3 meV in comparison to the theoretical prediction, evaluated with the CODATA radius. Higher-dimensional gravity is a candidate to explain this discrepancy, since the muon-proton gravitational interaction is stronger than the electron-proton interaction and, in the context of braneworld models, the gravitational potential can be hugely amplified in short distances when compared to the Newtonian potential. Motivated by these ideas, we study a muonic hydrogen confined in a thick brane. We show that the muon-proton gravitational interaction modified by extra dimensions can provide the additional separation of 0.3 meV between the 2S and 2P states. In this scenario, the gravitational energy depends on the higher-dimensional Planck mass and indirectly on the brane thickness. Studying the behavior of the gravitational energy with respect to the brane thickness in a realistic range, we find constraints for the fundamental Planck mass that solve the proton radius puzzle and are consistent with previous experimental bounds. (orig.)
Fractures of the distal radius in children: A retrospective evaluation
Directory of Open Access Journals (Sweden)
Selma Yazıcı
2012-06-01
Full Text Available Objectives: This study designed to evaluate the resultsof treatment, closed reduction and percutaneous wires, ofthe distal radius fractures in children.Materials and methods: A retrospective analysis wascarried out in children aged between 5-15 years who presentedwith a displaced fracture of the distal radius to ourhospital. They were initially treated with closed reductionand cast immobilization. If the fractures redisplaced treatedby percutaneous Kirschner (K- wire with scope undera general anaesthesia.Results: Totally 104 patients, who have distal radius fractureswere treated by closed reduction and immobilizationin a plaster cast. 13 patient who have distal radiusfractures were treated by closed reduction under generalanaesthesia and fixed by percutaneous Kirschner (K-wire. Patients with impaired the alignment of the fracturein late period were usually completely displaced fractures.(n=5, 4,3%, in early period, completely displaced fractures(n=5, 4,3% are superior to partial displaced fractures(n=2, 1,7%.Conclusion: In our study, when children with distal radiusfracture first come, they were treated by closed reductionand immobilization in a plaster cast. We thought that inredisplaced fractures patients were suitable for the closedreduction with percutaneous wire treatment.
Conversion of radius of curvature to power (and vice versa)
Wickenhagen, Sven; Endo, Kazumasa; Fuchs, Ulrike; Youngworth, Richard N.; Kiontke, Sven R.
2015-09-01
Manufacturing optical components relies on good measurements and specifications. One of the most precise measurements routinely required is the form accuracy. In practice, form deviation from the ideal surface is effectively low frequency errors, where the form error most often accounts for no more than a few undulations across a surface. These types of errors are measured in a variety of ways including interferometry and tactile methods like profilometry, with the latter often being employed for aspheres and general surface shapes such as freeforms. This paper provides a basis for a correct description of power and radius of curvature tolerances, including best practices and calculating the power value with respect to the radius deviation (and vice versa) of the surface form. A consistent definition of the sagitta is presented, along with different cases in manufacturing that are of interest to fabricators and designers. The results make clear how the definitions and results should be documented, for all measurement setups. Relationships between power and radius of curvature are shown that allow specifying the preferred metric based on final accuracy and measurement method. Results shown include all necessary equations for conversion to give optical designers and manufacturers a consistent and robust basis for decision-making. The paper also gives guidance on preferred methods for different scenarios for surface types, accuracy required, and metrology methods employed.
Characterizing SL2S galaxy groups using the Einstein radius
DEFF Research Database (Denmark)
Verdugo, T.; Motta, V.; Foex, G.
2014-01-01
Aims. We aim to study the reliability of RA (the distance from the arcs to the center of the lens) as a measure of the Einstein radius in galaxy groups. In addition, we want to analyze the possibility of using RA as a proxy to characterize some properties of galaxy groups, such as luminosity (L......) and richness (N). Methods. We analyzed the Einstein radius, θE, in our sample of Strong Lensing Legacy Survey (SL2S) galaxy groups, and compared it with RA, using three different approaches: 1) the velocity dispersion obtained from weak lensing assuming a singular isothermal sphere profile (θE,I); 2) a strong.......7 ± 0.2)RA, θE,II = (0.4 ± 1.5) + (1.1 ± 0.4)RA, and θE,III = (0.4 ± 1.5) + (0.9 ± 0.3)RA for each method respectively. We found weak evidence of anti-correlation between RA and z, with Log RA = (0.58 ± 0.06) − (0.04 ± 0.1)z, suggesting a possible evolution of the Einstein radius with z, as reported...
Factors associated with infection following open distal radius fractures.
Glueck, Dane A; Charoglu, Constantine P; Lawton, Jeffrey N
2009-09-01
Open fractures are often classified according to a system described by Gustilo and Anderson. However, this system was applied to open long bone fractures, which may not predict the incidence of infection in open metaphyseal fractures of the upper extremity. Other studies have found that wound contamination and systemic illness were the best predictors of infections in open hand fractures. Our study assessed infection in open distal radius fractures and identifies factors that are associated with these infections. We hypothesize that contamination, rather than absolute wound size, is the best predictor of infection associated with open distal radius fractures. A review by CPT code yielded 42 patients with open distal radius fractures between 1997 and 2002 treated at a level one trauma center. Medical records and radiographic follow-up were reviewed to assess the time to irrigation and debridement, the number of debridements in initial treatment period, the method of operative stabilization, the Gustilo and Anderson type of fracture, the Swanson type of fracture, and description of wound contamination. Forty-two patients were followed up for an average of 15 months (range 4 to 68 months). Twenty-four fractures were classified as Gustilo and Anderson type I, ten were type II, and eight were type III, 30 were Swanson type I, and 12 were Swanson type II. Five of the 42 fractures were considered contaminated. Two were exposed to fecal contamination. The others were contaminated with tar, dirt/grass, and gravel, respectively. Three of 42 (7%) fractures developed infections. All three infected cases received a single irrigation and debridement. Two of five contaminated fractures (40%) developed a polymicrobial infection. Both were exposed to fecal contamination and, therefore, considered Swanson type II fractures. They were classified as Gustilo and Anderson type II and IIIB based solely upon the size of the wound. Both required multiple debridements and eventually wrist
Estimates of the Hyperbolic Radius Gradient and Schwarz–Pick Inequalities for the Eccentric Annulus
Directory of Open Access Journals (Sweden)
D.Kh. Giniyatova
2016-06-01
Full Text Available Let Ω and Π be hyperbolic domains in the complex plane C. By A(Ω, Π we shall designate the class of functions f which are holomorphic or meromorphic in Ω and such that f(Ω ϲ Π. Estimates of the higher derivatives |f(n(z| of the analytic functions from the class A(Ω, Π with the punishing factor Cn(Ω, Π is one of the main problems of geometric theory of functions. These estimates are commonly referred to as Schwarz–Pick inequalities. Many results concerning this problem have been obtained for simply connected domains. Therefore, the research interest in such problems for finitely connected domains is natural. As known, the constant C2(Ω, Π for any pairs of hyperbolic domains depends only on the hyperbolic radius gradient of the corresponding domains. The main result of this paper is estimates of the hyperbolic radius gradient and the punishing factor in the Schwarz–Pick inequality for the eccentric annulus. We also consider the extreme case – the randomly punctured circle.
Constraints on the outer radius of the broad emission line region of active galactic nuclei
Landt, Hermine; Ward, Martin J.; Elvis, Martin; Karovska, Margarita
2014-03-01
Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Paα and Paβ, and find that it scales with the ionizing continuum luminosity roughly as expected from photoionization theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution in orbital motion and an accretion disc wind if the ratio between the BELR outer and inner radius is assumed to be less than ˜100-200. On the other hand, a pure Keplerian disc can be largely excluded, since for most orientations and radial extents of the disc the emission line profile is double-horned.
Measurement of Capillary Radius and Contact Angle within Porous Media.
Ravi, Saitej; Dharmarajan, Ramanathan; Moghaddam, Saeed
2015-12-01
The pore radius (i.e., capillary radius) and contact angle determine the capillary pressure generated in a porous medium. The most common method to determine these two parameters is through measurement of the capillary pressure generated by a reference liquid (i.e., a liquid with near-zero contact angle) and a test liquid. The rate of rise technique, commonly used to determine the capillary pressure, results in significant uncertainties. In this study, we utilize a recently developed technique for independently measuring the capillary pressure and permeability to determine the equivalent minimum capillary radii and contact angle of water within micropillar wick structures. In this method, the experimentally measured dryout threshold of a wick structure at different wicking lengths is fit to Darcy's law to extract the maximum capillary pressure generated by the test liquid. The equivalent minimum capillary radii of different wick geometries are determined by measuring the maximum capillary pressures generated using n-hexane as the working fluid. It is found that the equivalent minimum capillary radius is dependent on the diameter of pillars and the spacing between pillars. The equivalent capillary radii of micropillar wicks determined using the new method are found to be up to 7 times greater than the current geometry-based first-order estimates. The contact angle subtended by water at the walls of the micropillars is determined by measuring the capillary pressure generated by water within the arrays and the measured capillary radii for the different geometries. This mean contact angle of water is determined to be 54.7°.
NEUTRON STAR MASS–RADIUS CONSTRAINTS USING EVOLUTIONARY OPTIMIZATION
Energy Technology Data Exchange (ETDEWEB)
Stevens, A. L.; Morsink, S. M. [Department of Physics, University of Alberta, 4-183 CCIS, Edmonton, AB, T6G 2E1 (Canada); Fiege, J. D. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Leahy, D. A. [Department of Physics, University of Calgary, 2500 University Drive NW, Calgary, AB, T2N 1N4 (Canada)
2016-12-20
The equation of state of cold supra-nuclear-density matter, such as in neutron stars, is an open question in astrophysics. A promising method for constraining the neutron star equation of state is modeling pulse profiles of thermonuclear X-ray burst oscillations from hot spots on accreting neutron stars. The pulse profiles, constructed using spherical and oblate neutron star models, are comparable to what would be observed by a next-generation X-ray timing instrument like ASTROSAT , NICER , or a mission similar to LOFT . In this paper, we showcase the use of an evolutionary optimization algorithm to fit pulse profiles to determine the best-fit masses and radii. By fitting synthetic data, we assess how well the optimization algorithm can recover the input parameters. Multiple Poisson realizations of the synthetic pulse profiles, constructed with 1.6 million counts and no background, were fitted with the Ferret algorithm to analyze both statistical and degeneracy-related uncertainty and to explore how the goodness of fit depends on the input parameters. For the regions of parameter space sampled by our tests, the best-determined parameter is the projected velocity of the spot along the observer’s line of sight, with an accuracy of ≤3% compared to the true value and with ≤5% statistical uncertainty. The next best determined are the mass and radius; for a neutron star with a spin frequency of 600 Hz, the best-fit mass and radius are accurate to ≤5%, with respective uncertainties of ≤7% and ≤10%. The accuracy and precision depend on the observer inclination and spot colatitude, with values of ∼1% achievable in mass and radius if both the inclination and colatitude are ≳60°.
HABITABILITY OF EXOMOONS AT THE HILL OR TIDAL LOCKING RADIUS
Energy Technology Data Exchange (ETDEWEB)
Hinkel, Natalie R.; Kane, Stephen R., E-mail: natalie.hinkel@gmail.com [NASA Exoplanet Science Institute, Caltech, MS 100-22, 770 South Wilson Avenue, Pasadena, CA 91125 (United States)
2013-09-01
Moons orbiting extrasolar planets are the next class of object to be observed and characterized for possible habitability. Like the host-planets to their host-star, exomoons have a limiting radius at which they may be gravitationally bound, or the Hill radius. In addition, they also have a distance at which they will become tidally locked and therefore in synchronous rotation with the planet. We have examined the flux phase profile of a simulated, hypothetical moon orbiting at a distant radius around the confirmed exoplanets {mu} Ara b, HD 28185 b, BD +14 4559 b, and HD 73534 b. The irradiated flux on a moon at its furthest, stable distance from the planet achieves its largest flux gradient, which places a limit on the flux ranges expected for subsequent (observed) moons closer in orbit to the planet. We have also analyzed the effect of planetary eccentricity on the flux on the moon, examining planets that traverse the habitable zone either fully or partially during their orbit. Looking solely at the stellar contributions, we find that moons around planets that are totally within the habitable zone experience thermal equilibrium temperatures above the runaway greenhouse limit, requiring a small heat redistribution efficiency. In contrast, exomoons orbiting planets that only spend a fraction of their time within the habitable zone require a heat redistribution efficiency near 100% in order to achieve temperatures suitable for habitability. This means that a planet does not need to spend its entire orbit within the habitable zone in order for the exomoon to be habitable. Because the applied systems comprise giant planets around bright stars, we believe that the transit detection method is most likely to yield an exomoon discovery.
HABITABILITY OF EXOMOONS AT THE HILL OR TIDAL LOCKING RADIUS
International Nuclear Information System (INIS)
Hinkel, Natalie R.; Kane, Stephen R.
2013-01-01
Moons orbiting extrasolar planets are the next class of object to be observed and characterized for possible habitability. Like the host-planets to their host-star, exomoons have a limiting radius at which they may be gravitationally bound, or the Hill radius. In addition, they also have a distance at which they will become tidally locked and therefore in synchronous rotation with the planet. We have examined the flux phase profile of a simulated, hypothetical moon orbiting at a distant radius around the confirmed exoplanets μ Ara b, HD 28185 b, BD +14 4559 b, and HD 73534 b. The irradiated flux on a moon at its furthest, stable distance from the planet achieves its largest flux gradient, which places a limit on the flux ranges expected for subsequent (observed) moons closer in orbit to the planet. We have also analyzed the effect of planetary eccentricity on the flux on the moon, examining planets that traverse the habitable zone either fully or partially during their orbit. Looking solely at the stellar contributions, we find that moons around planets that are totally within the habitable zone experience thermal equilibrium temperatures above the runaway greenhouse limit, requiring a small heat redistribution efficiency. In contrast, exomoons orbiting planets that only spend a fraction of their time within the habitable zone require a heat redistribution efficiency near 100% in order to achieve temperatures suitable for habitability. This means that a planet does not need to spend its entire orbit within the habitable zone in order for the exomoon to be habitable. Because the applied systems comprise giant planets around bright stars, we believe that the transit detection method is most likely to yield an exomoon discovery
Fractal analysis of bone architecture at distal radius
International Nuclear Information System (INIS)
Tomomitsu, Tatsushi; Mimura, Hiroaki; Murase, Kenya; Sone, Teruki; Fukunaga, Masao
2005-01-01
Bone strength depends on bone quality (architecture, turnover, damage accumulation, and mineralization) as well as bone mass. In this study, human bone architecture was analyzed using fractal image analysis, and the clinical relevance of this method was evaluated. The subjects were 12 healthy female controls and 16 female patients suspected of having osteoporosis (age range, 22-70 years; mean age, 49.1 years). High-resolution CT images of the distal radius were acquired and analyzed using a peripheral quantitative computed tomography (pQCT) system. On the same day, bone mineral densities of the lumbar spine (L-BMD), proximal femur (F-BMD), and distal radius (R-BMD) were measured by dual-energy X-ray absorptiometry (DXA). We examined the correlation between the fractal dimension and six bone mass indices. Subjects diagnosed with osteopenia or osteoporosis were divided into two groups (with and without vertebral fracture), and we compared measured values between these two groups. The fractal dimension correlated most closely with L-BMD (r=0.744). The coefficient of correlation between the fractal dimension and L-BMD was very similar to the coefficient of correlation between L-BMD and F-BMD (r=0.783) and the coefficient of correlation between L-BMD and R-BMD (r=0.742). The fractal dimension was the only measured value that differed significantly between both the osteopenic and the osteoporotic subjects with and without vertebral fracture. The present results suggest that the fractal dimension of the distal radius can be reliably used as a bone strength index that reflects bone architecture as well as bone mass. (author)
Trajectory Calculator for Finite-Radius Cutter on a Lathe
Savchenkov, Anatoliy; Strekalov, Dmitry; Yu, Nan
2009-01-01
A computer program calculates the two-dimensional trajectory (radial vs. axial position) of a finite-radius-of-curvature cutting tool on a lathe so as to cut a workpiece to a piecewise-continuous, analytically defined surface of revolution. (In the original intended application, the tool is a diamond cutter, and the workpiece is made of a crystalline material and is to be formed into an optical resonator disk.) The program also calculates an optimum cutting speed as F/L, where F is a material-dependent empirical factor and L is the effective instantaneous length of the cutting edge.
Modelling Acoustic Wave Propagation in Axisymmetric Varying-Radius Waveguides
DEFF Research Database (Denmark)
Bæk, David; Willatzen, Morten
2008-01-01
A computationally fast and accurate model (a set of coupled ordinary differential equations) for fluid sound-wave propagation in infinite axisymmetric waveguides of varying radius is proposed. The model accounts for fluid heat conduction and fluid irrotational viscosity. The model problem is solved...... by expanding solutions in terms of cross-sectional eigenfunctions following Stevenson’s method. A transfer matrix can be easily constructed from simple model responses of a given waveguide and later used in computing the response to any complex wave input. Energy losses due to heat conduction and viscous...
Paediatric post-traumatic cortical defects of the distal radius
International Nuclear Information System (INIS)
Roach, Richard T.; Summers, Bruce N.; Cassar-Pullicino, Victor
2002-01-01
Paediatric post-traumatic cortical defects, although rare, are predominately seen affecting the distal radius following a greenstick or torus fracture. We review the literature and present a further two cases supported by CT and MRI. Images from an acute greenstick fracture are also presented to help understand the pathogenesis. Defects are typically solitary on plain radiographs and are usually noticed late, proximal to the site of compression. They are non-expansile in an otherwise healthy child. CT and MRI may reveal smaller multiple subperiosteal defects. Typical defects require no further management other than reassurance and advice that they may occasionally cause discomfort but resolve with time. (orig.)
Charge Radius Measurement of the Halo Nucleus $^{11}$Li
Kluge, H-J; Kuehl, T; Simon, H; Wang, Haiming; Zimmermann, C; Onishi, T; Tanihata, I; Wakasugi, M
2002-01-01
%IS385 %title\\\\ \\\\The root-mean-square charge radius of $^{11}$Li will be determined by measuring the isotope shift of a suitable atomic transition in a laser spectroscopic experiment. Comparing the charge radii of the lithium isotopes obtained by this nuclear-model-independent method with the relevant mass radii obtained before will help to answer the question whether the proton distribution in halo nuclei at the neutron drip-line is decoupled to the first order from their neutron distribution. The necessary experimental sensitivity requires the maximum possible rate of $^{11}$Li nuclei in a beam of low emittance which can only be provided by ISOLDE.
International Nuclear Information System (INIS)
Idris, A; Pullen, K
2013-01-01
The effects of chamfering and corner radiusing on the discharge coefficient of rotating axial orifices are presented in this paper. Both experimental and CFD results show that chamfering and corner radiusing improve the discharge coefficient of rotating orifices. For non-inclined rotating orifices, the discharge coefficient reduces with increasing speed, but chamfered and radiused orifices manage to have higher discharge coefficient (C d ) than the straight edge orifices. Comparing between chamfering and corner radiusing, the radiused corner orifice has the highest C d at every rotational speed. This is because the inlet radius helps guiding the flow into the orifice and avoiding flow separation at the inlet.
International Nuclear Information System (INIS)
Ejima, S.; Petrie, T.W.; Riviere, A.C.
1982-01-01
The dependence of plasma energy confinement on minor radius, density and plasma current is described for Ohmically heated near-circular plasmas in Doublet III. A wide range of parameters is used for the study of scaling laws; the plasma minor radius defined by the flux surface in contact with limiter is varied by a factor of 2 (a = 44, 32, and 23 cm), the line average plasma density, nsub(e)-bar, is varied by a factor of 20 from 0.5 to 10 x 10 13 cm -3 (nsub(e)-bar R 0 /Bsub(T) = 0.3 to 6 x 10 14 cm -2 .kG -1 ) and the plasma current, I, is varied by a factor of 6 from 120 to 718 kA. The range of the limiter safety factor, qsub(L), is from 2 to 12. - For plasmas with a = 23 and 32 cm, the scaling law at low nsub(e)-bar for the gross electron energy confinement time can be written as (s, cm) tausub(Ee)sup(G) approx.= 3.6 x 10 -19 nsub(e)-bar a 2 qsub(c)sup(3/4), where qsub(c) = 2πa 2 Bsub(T)/μ 0 IR 0 . For the 44-cm plasmas, tausub(Ee)sup(G) is about 1.8 times less than predicted by this scaling, possibly owing to the change in limiter configuration and small plasma-wall separation and/or the aspect ratio change. At high nsub(e)-bar, tausub(Ee)sup(G) saturates and in many cases decreases with nsub(e)-bar but increases with I in a classical-like manner. The dependence of tausub(Ee)sup(G) on a is considerably weakened. The confinement behaviour can be explained by taking an ion thermal conductivity 2 to 7 times that given by Hinton-Hazeltine's neoclassical theory with a lumped-Zsub(eff) impurity model. Within this range the enhancement factor increases with a or a/R 0 . The electron thermal conductivity evaluated at half-temperature radius where most of the thermal insulation occurs sharply increases with average current density within that radius, but does not depend on a within the uncertainties of the measurements. (author)
Stellar Initial Mass Function: Trends With Galaxy Mass And Radius
Parikh, Taniya
2017-06-01
There is currently no consensus about the exact shape and, in particular, the universality of the stellar initial mass function (IMF). For massive galaxies, it has been found that near-infrared (NIR) absorption features, which are sensitive to the ratio of dwarf to giant stars, deviate from a Milky Way-like IMF; their modelling seems to require a larger fraction of low mass stars. There are now increasing results looking at whether the IMF varies not only with galaxy mass, but also radially within galaxies. The SDSS-IV/MaNGA integral-field survey will provide spatially resolved spectroscopy for 10,000 galaxies at R 2000 from 360-1000nm. Spectra of early-type galaxies were stacked to achieve high S/N which is particularly important for features in the NIR. Trends with galaxy radius and mass were compared to stellar population models for a range of absorption features in order to separate degeneracies due to changes in stellar population parameters, such as age, metallicity and element abundances, with potential changes in the IMF. Results for 611 galaxies show that we do not require an IMF steeper than Kroupa as a function of galaxy mass or radius based on the NaI index. The Wing-Ford band hints towards a steeper IMF at large radii however we do not have reliable measurements for the most massive galaxies.
Electromagnetic Charge Radius of the Pion at High Precision
Ananthanarayan, B.; Caprini, Irinel; Das, Diganta
2017-09-01
We present a determination of the pion charge radius from high precision data on the pion vector form factor from both timelike and spacelike regions, using a novel formalism based on analyticity and unitarity. At low energies, instead of the poorly known modulus of the form factor, we use its phase, known with high accuracy from Roy equations for π π elastic scattering via the Fermi-Watson theorem. We use also the values of the modulus at several higher timelike energies, where the data from e+e- annihilation and τ decay are mutually consistent, as well as the most recent measurements at spacelike momenta. The experimental uncertainties are implemented by Monte Carlo simulations. The results, which do not rely on a specific parametrization, are optimal for the given input information and do not depend on the unknown phase of the form factor above the first inelastic threshold. Our prediction for the charge radius of the pion is rπ=(0.657 ±0.003 ) fm , which amounts to an increase in precision by a factor of about 2.7 compared to the Particle Data Group average.
Radius scaling of titanium wire arrays on the Z accelerator
International Nuclear Information System (INIS)
Coverdale, C.A.; Denney, C.; Spielman, R.B.
1999-01-01
The 20 MA Z accelerator has made possible the generation of substantial radiation (> 100 kJ) at higher photon energies (4.8 keV) through the use of titanium wire arrays. In this paper, the results of experiments designed to study the effects of initial load radius variations of nickel-clad titanium wire arrays will be presented. The load radius was varied from 17.5 mm to 25 mm and titanium K-shell (4.8 keV) yields of greater than 100 kJ were measured. The inclusion of the nickel cladding on the titanium wires allows for higher wire number loads and increases the spectral broadness of the source; kilovolt emissions (nickel plus titanium L-shell) of 400 kJ were measured in these experiments. Comparisons of the data to calculations will be made to estimate pinched plasma parameters such as temperature and participating mass fraction. These results will also be compared with previous pure titanium wire array results
Hydroforming Process for an Ultrasmall Bending Radius Elbow
Directory of Open Access Journals (Sweden)
Shangwen Ruan
2018-01-01
Full Text Available Bent pipes are widely used in automotive, aviation, and aerospace industries for delivering fluids. Parts having small relative bending radiuses are called elbows. However, fabricating a thin-walled elbow part using the simple bending process poses many challenges. One possible way to manufacture elbows is with the stamping-welding process. The major drawbacks of this method include the decline in sealing performance and the addition in weight attributed to the lap welding process. Tube hydroforming (THF is considered as a feasible solution to these problems. However, the forming process could be quite complex, and multistep forming is necessary. This study investigates the effects of preliminary processes on elbow forming such as bending, partition forming, and heat treatment and presents a high-performance optimized process design to achieve an ultrasmall radius elbow. The effects of multistep forming on the thickness distribution and the heat treatment on the microstructure have been evaluated. The results obtained from simulations show a reasonable agreement with those from the experiments.
Phenomenology of single-inclusive jet production with jet radius and threshold resummation
Liu, Xiaohui; Moch, Sven-Olaf; Ringer, Felix
2018-03-01
We perform a detailed study of inclusive jet production cross sections at the LHC and compare the QCD theory predictions based on the recently developed formalism for threshold and jet radius joint resummation at next-to-leading logarithmic accuracy to inclusive jet data collected by the CMS Collaboration at √{S }=7 and 13 TeV. We compute the cross sections at next-to-leading order in QCD with and without the joint resummation for different choices of jet radii R and observe that the joint resummation leads to crucial improvements in the description of the data. Comprehensive studies with different parton distribution functions demonstrate the necessity of considering the joint resummation in fits of those functions based on the LHC jet data.
Takagi, Hiroshi; Wu, Wenjie
2016-03-01
Even though the maximum wind radius (Rmax) is an important parameter in determining the intensity and size of tropical cyclones, it has been overlooked in previous storm surge studies. This study reviews the existing estimation methods for Rmax based on central pressure or maximum wind speed. These over- or underestimate Rmax because of substantial variations in the data, although an average radius can be estimated with moderate accuracy. As an alternative, we propose an Rmax estimation method based on the radius of the 50 kt wind (R50). Data obtained by a meteorological station network in the Japanese archipelago during the passage of strong typhoons, together with the JMA typhoon best track data for 1990-2013, enabled us to derive the following simple equation, Rmax = 0.23 R50. Application to a recent strong typhoon, the 2015 Typhoon Goni, confirms that the equation provides a good estimation of Rmax, particularly when the central pressure became considerably low. Although this new method substantially improves the estimation of Rmax compared to the existing models, estimation errors are unavoidable because of fundamental uncertainties regarding the typhoon's structure or insufficient number of available typhoon data. In fact, a numerical simulation for the 2013 Typhoon Haiyan as well as 2015 Typhoon Goni demonstrates a substantial difference in the storm surge height for different Rmax. Therefore, the variability of Rmax should be taken into account in storm surge simulations (e.g., Rmax = 0.15 R50-0.35 R50), independently of the model used, to minimize the risk of over- or underestimating storm surges. The proposed method is expected to increase the predictability of major storm surges and to contribute to disaster risk management, particularly in the western North Pacific, including countries such as Japan, China, Taiwan, the Philippines, and Vietnam.
Power decoding Reed-Solomon codes up to the Johnson radius
DEFF Research Database (Denmark)
Rosenkilde, Johan Sebastian Heesemann
2018-01-01
Power decoding, or "decoding using virtual interleaving" is a technique for decoding Reed-Solomon codes up to the Sudan radius. Since the method's inception, it has been an open question if it is possible to use this approach to decode up to the Johnson radius - the decoding radius of the Guruswami...
Small-radius jets to all orders in QCD
Dasgupta, Mrinal; Salam, Gavin P.; Soyez, Gregory
2015-01-01
As hadron collider physics continues to push the boundaries of precision, it becomes increasingly important to have methods for predicting properties of jets across a broad range of jet radius values R, and in particular for small R. In this paper we resum all leading logarithmic terms, $\\alpha_s^n \\ln^n R$, in the limit of small R, for a wide variety of observables. These include the inclusive jet spectrum, jet vetoes for Higgs physics and jet substructure tools. Some of the quantities that we consider are relevant also for heavy-ion collisions. Furthermore, we examine and comment on the underlying order-by-order convergence of the perturbative series for different R values. Our results indicate that small-R effects can be substantial. Phenomenological studies will appear in a forthcoming companion paper.
Inclusive jet spectrum for small-radius jets
Dasgupta, Mrinal; Salam, Gavin P.; Soyez, Gregory
2016-01-01
Following on our earlier work on leading-logarithmic (LLR) resummations for the properties of jets with a small radius, R, we here examine the phenomenological considerations for the inclusive jet spectrum. We discuss how to match the NLO predictions with small-R resummation. As part of the study we propose a new, physically-inspired prescription for fixed-order predictions and their uncertainties. We investigate the R-dependent part of the next-to-next-to-leading order (NNLO) corrections, which is found to be substantial, and comment on the implications for scale choices in inclusive jet calculations. We also examine hadronisation corrections, identifying potential limitations of earlier analytical work with regards to their $p_t$-dependence. Finally we assemble these different elements in order to compare matched (N)NLO+LLR predictions to data from ALICE and ATLAS, finding improved consistency for the R-dependence of the results relative to NLO predictions.
Small-radius jets to all orders in QCD
Energy Technology Data Exchange (ETDEWEB)
Dasgupta, Mrinal [Consortium for Fundamental Physics, School of Physics & Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Dreyer, Frédéric [Sorbonne Universités, UPMC Univ Paris 06, UMR 7589, LPTHE, F-75005, Paris (France); CNRS, UMR 7589, LPTHE, F-75005, Paris (France); Salam, Gavin P. [CERN, PH-TH, CH-1211 Geneva 23 (Switzerland); Soyez, Gregory [IPhT, CEA Saclay, CNRS URA 2306, F-91191 Gif-sur-Yvette (France)
2015-04-08
As hadron collider physics continues to push the boundaries of precision, it becomes increasingly important to have methods for predicting properties of jets across a broad range of jet radius values R, and in particular for small R. In this paper we resum all leading logarithmic terms, α{sub s}{sup n}ln{sup n} R{sup 2}, in the limit of small R, for a wide variety of observables. These include the inclusive jet spectrum, jet vetoes for Higgs physics and jet substructure tools. Some of the quantities that we consider are relevant also for heavy-ion collisions. Furthermore, we examine and comment on the underlying order-by-order convergence of the perturbative series for different R values. Our results indicate that small-R effects can be substantial. Phenomenological studies will appear in a forthcoming companion paper.
Proton radius, Darwin-Foldy term and radiative corrections
International Nuclear Information System (INIS)
Jentschura, U.D.
2011-01-01
We discuss the role of the so-called Darwin-Foldy term in the evaluation of the proton and deuteron charge radii from atomic hydrogen spectroscopy and nuclear scattering data. The question of whether this term should be included or excluded from the nuclear radius has been controversially discussed in the literature. We attempt to clarify which literature values correspond to which conventions. A detailed discussion of the conventions appears useful because a recent experiment [R. Pohl et al., Nature 466, 213 (2010)] has indicated that there is a discrepancy between the proton charge radii inferred from ordinary ('electronic') atomic hydrogen and muonic hydrogen. We also investigate the role of quantum electrodynamic radiative corrections in the determination of nuclear radii from scattering data, and propose a definition of the nuclear self energy which is compatible with the subtraction of the radiative corrections in scattering experiments. (author)
Mass-radius relation for magnetized strange quark stars
Martinez, A Perez; Paret, D Manreza
2010-01-01
We review the stability of magnetized strange quark matter (MSQM) within the phenomenological MIT bag model, taking into account the variation of the relevant input parameters, namely, the strange quark mass, baryon density, magnetic field and bag parameter. A comparison with magnetized asymmetric quark matter in $\\beta$-equilibrium as well as with strange quark matter (SQM) is presented. We obtain that the energy per baryon for MSQM decreases as the magnetic field increases, and its minimum value at vanishing pressure is lower than the value found for SQM, which implies that MSQM is more stable than non-magnetized SQM. The mass-radius relation for magnetized strange quark stars is also obtained in this framework.
Inductive voltage adder (IVA) for submillimeter radius electron beam
International Nuclear Information System (INIS)
Mazarakis, M.G.; Poukey, J.W.; Maenchen, J.E.
1996-01-01
The authors have already demonstrated the utility of inductive voltage adder accelerators for production of small-size electron beams. In this approach, the inductive voltage adder drives a magnetically immersed foilless diode to produce high-energy (10--20 MeV), high-brightness pencil electron beams. This concept was first demonstrated with the successful experiments which converted the linear induction accelerator RADLAC II into an IVA fitted with a small 1-cm radius cathode magnetically immersed foilless diode (RADLAC II/SMILE). They present here first validations of extending this idea to mm-scale electron beams using the SABRE and HERMES-III inductive voltage adders as test beds. The SABRE experiments are already completed and have produced 30-kA, 9-MeV electron beams with envelope diameter of 1.5-mm FWHM. The HERMES-III experiments are currently underway
Relation between radius and expansion velocity in planetary nebulae
International Nuclear Information System (INIS)
Chu, Y.H.; Kwitter, K.B.; Kaler, J.B.
1984-01-01
The expansion velocity-radius (R-V) relation for planetary nebulae is examined using the existing measurements of expansion velocities and recent calculations of radii. It is found that some of the previously alleged R-V relations for PN are not convincingly established. The scatter in the R-V plots may be due largely to stratification of ions in individual nebulae and to heterogeneity in the planetary nebula population. In addition, from new echelle/CCD observations of planetary nebulae, it is found that spatial information is essential in deriving the internal kinematic properties. Future investigations of R-V relations should be pursued separately for groups of planetaries with similar physical properties, and they should employ observations of appropriate low excitation lines in order to measure the expansion velocity at the surface of the nebula. 26 references
Nuclear charge radius measurements of radioactive beryllium isotopes
2002-01-01
We propose to measure the nuclear charge radii of the beryllium isotopes $^{7,9,10}$Be and the one-neutron halo isotope $^{11}$Be using laser spectroscopy of trapped ions. Ions produced at ISOLDE and ionized with the laser ion source will be cooled and bunched in the radio-frequency buncher of the ISOLTRAP experiment and then transferred into a specially designed Paul trap. Here, they will be cooled to temperatures in the mK range employing sympathetic and direct laser cooling. Precision laser spectroscopy of the isotope shift on the cooled ensemble in combination with accurate atomic structure calculations will provide nuclear charge radii with a precision of better than 3%. This will be the first model-independent determination of a one-neutron halo nuclear charge radius.
Reliability of radiographic measurements for acute distal radius fractures
International Nuclear Information System (INIS)
Watson, Narelle J.; Asadollahi, Saeed; Parrish, Frank; Ridgway, Jacqueline; Tran, Phong; Keating, Jennifer L.
2016-01-01
The management of distal radial fractures is guided by the interpretation of radiographic findings. The aim of this investigation was to determine the intra- and inter-observer reliability of eight traditionally reported anatomic radiographic parameters in adults with an acute distal radius fracture. Five observers participated. All were routinely involved in making treatment decisions based on distal radius fracture radiographs. Observers performed independent repeated measurements on 30 radiographs for eight anatomical parameters: dorsal shift (mm), intra-articular gap (mm), intra-articular step (mm), palmar tilt (degrees), radial angle (degrees), radial height (mm), radial shift (mm), ulnar variance (mm). Intraclass correlation coefficients (ICCs) and the magnitude of retest errors were calculated. Measurement reliability was summarised as high (ICC > 0.80), moderate (0.60–0.80) or low (<0.60). Intra-observer reliability was high for dorsal shift and palmar tilt; moderate for radial angle, radial height, ulnar variance and radial shift; and low for intra-articular gap and step. Inter-observer reliability was high for palmar tilt; moderate for dorsal shift, ulnar variance, radial angle and radial height; and low for radial shift, intra-articular gap and step. Error magnitude (95 % confidence interval) was within 1–2 mm for intra-articular gap and step, 2–4 mm for ulnar variance, 4–6 mm for radial shift, dorsal shift and radial height, and 6–8° for radial angle and palmar tilt. Based on previous reports of critical values for palmar tilt, ulnar variance and radial angle, error margins appear small enough for measurements to be useful in guiding treatment decisions. Our findings indicate that clinicians cannot reliably measure values ≤1 mm for intra-articular gap and step when interpreting radiographic parameters using the standardised methods investigated in this study. As a guide for treatment selection, palmar tilt, ulnar variance and radial angle
The semi-inclusive jet function in SCET and small radius resummation for inclusive jet production
International Nuclear Information System (INIS)
Kang, Zhong-Bo; Ringer, Felix; Vitev, Ivan
2016-01-01
We introduce a new kind of jet function: the semi-inclusive jet function J_i(z,ω_J,μ), which describes how a parton i is transformed into a jet with a jet radius R and energy fraction z=ω_J/ω, with ω_J and ω being the large light-cone momentum component of the jet and the corresponding parton i that initiates the jet, respectively. Within the framework of Soft Collinear Effective Theory (SCET) we calculate both J_q(z,ω_J,μ) and J_g(z,ω_J,μ) to the next-to-leading order (NLO) for cone and anti-k_T algorithms. We demonstrate that the renormalization group (RG) equations for J_i(z,ω_J,μ) follow exactly the usual DGLAP evolution, which can be used to perform the ln R resummation for inclusive jet cross sections with a small jet radius R. We clarify the difference between our RG equations for J_i(z,ω_J,μ) and those for the so-called unmeasured jet functions J_i(ω_J,μ), widely used in SCET for exclusive jet production. Finally, we present applications of the new semi-inclusive jet functions to inclusive jet production in e"+e"− and pp collisions. We demonstrate that single inclusive jet production in these collisions shares the same short-distance hard functions as single inclusive hadron production, with only the fragmentation functions D_i"h(z,μ) replaced by J_i(z,ω_J,μ). This can facilitate more efficient higher-order analytical computations of jet cross sections. We further match our ln R resummation at both LL_R and NLL_R to fixed NLO results and present the phenomenological implications for single inclusive jet production at the LHC.
Inclusive jet spectrum for small-radius jets
Energy Technology Data Exchange (ETDEWEB)
Dasgupta, Mrinal [Consortium for Fundamental Physics, School of Physics & Astronomy, University of Manchester,Manchester M13 9PL (United Kingdom); Dreyer, Frédéric A. [Sorbonne Universités, UPMC Univ Paris 06, UMR 7589, LPTHE,F-75005, Paris (France); CNRS, UMR 7589, LPTHE,F-75005, Paris (France); CERN, Theoretical Physics Department,CH-1211 Geneva 23 (Switzerland); Salam, Gavin P. [CERN, Theoretical Physics Department,CH-1211 Geneva 23 (Switzerland); Soyez, Gregory [IPhT, CEA Saclay, CNRS UMR 3681,F-91191 Gif-sur-Yvette (France)
2016-06-09
Following on our earlier work on leading-logarithmic (LL{sub R}) resummations for the properties of jets with a small radius, R, we here examine the phenomenological considerations for the inclusive jet spectrum. We discuss how to match the NLO predictions with small-R resummation. As part of the study we propose a new, physically-inspired prescription for fixed-order predictions and their uncertainties. We investigate the R-dependent part of the next-to-next-to-leading order (NNLO) corrections, which is found to be substantial, and comment on the implications for scale choices in inclusive jet calculations. We also examine hadronisation corrections, identifying potential limitations of earlier analytical work with regards to their p{sub t}-dependence. Finally we assemble these different elements in order to compare matched (N)NLO+LL{sub R} predictions to data from ALICE and ATLAS, finding improved consistency for the R-dependence of the results relative to NLO predictions.
AO Distal Radius Fracture Classification: Global Perspective on Observer Agreement
Jayakumar, Prakash; Teunis, Teun; Giménez, Beatriz Bravo; Verstreken, Frederik; Di Mascio, Livio; Jupiter, Jesse B.
2016-01-01
Background The primary objective of this study was to test interobserver reliability when classifying fractures by consensus by AO types and groups among a large international group of surgeons. Secondarily, we assessed the difference in inter- and intraobserver agreement of the AO classification in relation to geographical location, level of training, and subspecialty. Methods A randomized set of radiographic and computed tomographic images from a consecutive series of 96 distal radius fractures (DRFs), treated between October 2010 and April 2013, was classified using an electronic web-based portal by an invited group of participants on two occasions. Results Interobserver reliability was substantial when classifying AO type A fractures but fair and moderate for type B and C fractures, respectively. No difference was observed by location, except for an apparent difference between participants from India and Australia classifying type B fractures. No statistically significant associations were observed comparing interobserver agreement by level of training and no differences were shown comparing subspecialties. Intra-rater reproducibility was “substantial” for fracture types and “fair” for fracture groups with no difference accounting for location, training level, or specialty. Conclusion Improved definition of reliability and reproducibility of this classification may be achieved using large international groups of raters, empowering decision making on which system to utilize. Level of Evidence Level III PMID:28119795
MASS-RADIUS RELATIONSHIPS FOR VERY LOW MASS GASEOUS PLANETS
International Nuclear Information System (INIS)
Batygin, Konstantin; Stevenson, David J.
2013-01-01
Recently, the Kepler spacecraft has detected a sizable aggregate of objects, characterized by giant-planet-like radii and modest levels of stellar irradiation. With the exception of a handful of objects, the physical nature, and specifically the average densities, of these bodies remain unknown. Here, we propose that the detected giant planet radii may partially belong to planets somewhat less massive than Uranus and Neptune. Accordingly, in this work, we seek to identify a physically sound upper limit to planetary radii at low masses and moderate equilibrium temperatures. As a guiding example, we analyze the interior structure of the Neptune-mass planet Kepler-30d and show that it is acutely deficient in heavy elements, especially compared with its solar system counterparts. Subsequently, we perform numerical simulations of planetary thermal evolution and in agreement with previous studies, show that generally, 10-20 M ⊕ , multi-billion year old planets, composed of high density cores and extended H/He envelopes can have radii that firmly reside in the giant planet range. We subject our results to stability criteria based on extreme ultraviolet radiation, as well as Roche-lobe overflow driven mass-loss and construct mass-radius relationships for the considered objects. We conclude by discussing observational avenues that may be used to confirm or repudiate the existence of putative low mass, gas-dominated planets.
Improved automatic optic nerve radius estimation from high resolution MRI
Harrigan, Robert L.; Smith, Alex K.; Mawn, Louise A.; Smith, Seth A.; Landman, Bennett A.
2017-02-01
The optic nerve (ON) is a vital structure in the human visual system and transports all visual information from the retina to the cortex for higher order processing. Due to the lack of redundancy in the visual pathway, measures of ON damage have been shown to correlate well with visual deficits. These measures are typically taken at an arbitrary anatomically defined point along the nerve and do not characterize changes along the length of the ON. We propose a fully automated, three-dimensionally consistent technique building upon a previous independent slice-wise technique to estimate the radius of the ON and surrounding cerebrospinal fluid (CSF) on high-resolution heavily T2-weighted isotropic MRI. We show that by constraining results to be three-dimensionally consistent this technique produces more anatomically viable results. We compare this technique with the previously published slice-wise technique using a short-term reproducibility data set, 10 subjects, follow-up <1 month, and show that the new method is more reproducible in the center of the ON. The center of the ON contains the most accurate imaging because it lacks confounders such as motion and frontal lobe interference. Long-term reproducibility, 5 subjects, follow-up of approximately 11 months, is also investigated with this new technique and shown to be similar to short-term reproducibility, indicating that the ON does not change substantially within 11 months. The increased accuracy of this new technique provides increased power when searching for anatomical changes in ON size amongst patient populations.
The strength of polyaxial locking interfaces of distal radius plates.
Hoffmeier, Konrad L; Hofmann, Gunther O; Mückley, Thomas
2009-10-01
Currently available polyaxial locking plates represent the consequent enhancement of fixed-angle, first-generation locking plates. In contrast to fixed-angle locking plates which are sufficiently investigated, the strength of the new polyaxial locking options has not yet been evaluated biomechanically. This study investigates the mechanical strength of single polyaxial interfaces of different volar radius plates. Single screw-plate interfaces of the implants Palmar 2.7 (Königsee Implantate und Instrumente zur Osteosynthese GmbH, Allendorf, Germany), VariAx (Stryker Leibinger GmbH & Co. KG, Freiburg, Germany) und Viper (Integra LifeSciences Corporation, Plainsboro, NJ, USA) were tested by cantilever bending. The strength of 0 degrees, 10 degrees and 20 degrees screw locking angle was obtained during static and dynamic loading. The Palmar 2.7 interfaces showed greater ultimate strength and fatigue strength than the interfaces of the other implants. The strength of the VariAx interfaces was about 60% of Palmar 2.7 in both, static and dynamic loading. No dynamic testing was applied to the Viper plate because of its low ultimate strength. By static loading, an increase in screw locking angle caused a reduction of strength for the Palmar 2.7 and Viper locking interfaces. No influence was observed for the VariAx locking interfaces. During dynamic loading; angulation had no influence on the locking strength of Palmar 2.7. However, reduction of locking strength with increasing screw angulation was observed for VariAx. The strength of the polyaxial locking interfaces differs remarkably between the examined implants. Depending on the implant an increase of the screw locking angle causes a reduction of ultimate or fatigue strength, but not in all cases a significant impact was observed.
On the determination of the proton RMS-radius from electron scattering data
International Nuclear Information System (INIS)
Borkowski, F.; Simon, G.G.; Walther, V.H.; Wendling, R.D.
1975-01-01
It is shown that the proton rms radius should be determined from fiting a polynomial of second order to the low-q 2 form factors. The commonly used polynomial of first yields radius values which are too small. The proton rms radius has been redetermined from an analysis of the electron scattering data measured at three laboratories. The best fit value is [r 2 sub(E)]sup(1/2) = 0.87 +- 0.02 fm. (orig.) [de
Study of the external parameters influence on the channel discharge radius in Hg lamps
International Nuclear Information System (INIS)
Cristea, M.
2000-01-01
In this paper, the plasma electric conductivity and the channel radius for high-pressure mercury arc discharge are calculated. The examined model emphasizes some correlations between various external parameters (current intensity, silicon tube diameter and working pressure) and the channel discharge radius. After model validation, the temperature distribution in the discharge zone is obtained and then the electrons and ions distribution, the electric carriers mobility and the electric conductivity for different lamp characteristics are calculated. The applied numerical simulation shows a linear increase of the channel radius with the tube radius Rw increasing, and a very week pressure dependence (in the range 0.5 - 5 atm.)
The separatrix radius measurement of field-reversed configuration plasma in FRX-L
International Nuclear Information System (INIS)
Zhang, Shouyin; Tejero, Erik M.; Taccetti, Jose Martin; Wurden, Glen A.; Intrator, Thomas; Waganaar, William J.
2004-01-01
Magnetic pick-up coils and single turn flux loops are installed on the FRX-L device. The combination of the two measurements provides the excluded flux radius that approximates the separatrix radius of the field-reversed configuration plasma. Arrays of similar probes are used to map out local magnetic field dynamics beyond both ends of the theta-coil confinement region to help understand the effects of cusp locations on flux trapping during the FRC formation process. Details on the probe design and system calibrations are presented. The overall system calibration of excluded flux radius measurement is examined by replacing FRC plasma with a known radius aluminum conductor cylinder.
Fractures of the bilateral distal radius and scaphoid: a case report
Directory of Open Access Journals (Sweden)
Ozkan Korhan
2008-03-01
Full Text Available Abstract Introduction Bilateral fractures of the distal radius and scaphoid are extremely rare injuries. Case presentation A patient with bilateral comminuted, displaced distal fractures of the radius and bilateral fractures of the scaphoid was treated via internal fixation of the scaphoid fractures with Herbert screws and internal fixation of the distal radius fractures with locked volar plating. Conclusion Rigid internal fixation of distal radius and scaphoid fractures is mandatory to start early active rehabilitation of the wrist without the need for wrist immobilization with a plaster or external skeletal fixation.
Linear stability of tearing modes
International Nuclear Information System (INIS)
Cowley, S.C.; Kulsrud, R.M.; Hahm, T.S.
1986-05-01
This paper examines the stability of tearing modes in a sheared slab when the width of the tearing layer is much smaller than the ion Larmor radius. The ion response is nonlocal, and the quasineutrality retains its full integal form. An expansion procedure is introduced to solve the quasineutrality equation in powers of the width of the tearing layer over the ion Larmor radius. The expansion procedure is applied to the collisionless and semi-collisional tearing modes. The first order terms in the expansion we find to be strongly stabilizing. The physics of the mode and of the stabilization is discussed. Tearing modes are observed in experiments even though the slab theory predicts stability. It is proposed that these modes grow from an equilibrium with islands at the rational surfaces. If the equilibrium islands are wider than the ion Larmor radius, the mode is unstable when Δ' is positive
International Nuclear Information System (INIS)
Hayns, M.R.; Mansur, L.K.
1985-01-01
Recently, a cascade diffusion theory was developed to understand cacade-induced fluctuations in point defect flux during irradiation. Application of the theory revealed that such fluctuations give rise to a mechanism of cascade-induced creep that is predicted to be of significant magnitude. Here we extend the investigation to the formation of cavities. Specifically, we explore the possible importance of cascade-induced cavity growth excursions in triggering a transition from the gas-content-dictated stable radius to the critical radius for bias-driven growth. Two methods of analysis are employed. The first uses the variance of fluctuations to assess the average effect of fluctuations. The second is based on the fact that in a large ensemble of cavities, a small fraction will experience larger than average excursions. This prospect is assessed by estimating upper limits to the processes. For the conditions considered, it is concluded that cascade-induced fluctuations are of minor importance in triggering the onset of swelling in a population of stable gas-containing cavities
Evaluation of sarcopenia in patients with distal radius fractures.
Roh, Young Hak; Koh, Young Do; Noh, Jung Ho; Gong, Hyun Sik; Baek, Goo Hyun
2017-12-01
Sarcopenia is more prevalent in patients with distal radius fracture (DRF) than in age- and sex-matched controls. Lower appendicular mass index in men and weaker grip strength in both men and women increase the likelihood of DRF. Sarcopenia is a core component of physical frailty that predisposes older people to falls and negatively impacts the activities of daily living. The objectives of this study were to compare the prevalence of sarcopenia in patients with DRF with that in age- and sex-matched controls without DRF; and evaluate the association between sarcopenia and the occurrence of DRF. We prospectively recruited 132 patients over 50 years of age who sustained DRF due to fall and 132 age- and sex-matched controls without DRF. A definition of sarcopenia was based on the consensus of the Asian Working Group for Sarcopenia. Sarcopenic components including appendicular lean body mass, grip strength, and gait speed were compared between the two groups. Other factors assessed for the occurrence of DRF were age, gender, body mass index (BMI), lumbar, and hip bone mineral density (BMD) values. A conditional logistic regression analysis was conducted to evaluate the associations between sarcopenia and the occurrence of DRF. A total of 39 (30%) of 132 DRF patients were sarcopenic, whereas 23 (17%) of the 132 controls were within the sarcopenic criteria (p = 0.048). The patient group had significantly lower lean body mass and weaker grip strength than those of the control group. However, there was no significant difference in gait speed between the two groups. According to regression analysis, lower appendicular mass index in men was associated with an increased incidence of DRF (odds ratio [OR] = 0.84, 95% confidence interval [CI] = 0.72, 0.95) while weaker grip strength and lower total hip BMD values were associated with the occurrence of DRF in both men (OR = 0.77, 95% CI = 0.63, 0.92; and OR = 0.79, 95% CI = 0.64, 0.94, respectively) and women (OR
Constraining the radius of neutron stars through the moment of inertia
International Nuclear Information System (INIS)
Greif, S.K.
2017-01-01
Neutron star observations provide systematic constraints on the nuclear equation of state like the recent discovery of 2 M neutron stars. While neutron star masses can be measured very precisely, their radii are inherently difficult to measure due to the influence from large systematic uncertainties. A promising alternative access to this information is the moment of inertia, which provides constraints for both radii and the equation of state. This will be possible in the future using pulsar timing observations. We present a theoretical framework for calculating moments of inertia microscopically. We use state-of-the-art equations of state that are based on chiral effective field theory interactions and fulfill the requirements of causality and of reproducing 2 M neutron stars. This allows us to generate a large set of equations of state that predict combinations of masses, radii, and moments of inertia. We investigate the impact of a moment of inertia measurement on the radius within this general setup. Based on our results, we show how future measurements of moments of inertia constrain radii of neutron stars and thus the equation of state. (author)
International Nuclear Information System (INIS)
Rieger, Michael; Gruber, Hannes; Jaschke, Werner R.; Gabl, Markus; Mallouhi, Ammar
2005-01-01
Our objective was to evaluate the usefulness of CT virtual preoperative planning in the surgical repositioning of malunited distal radius fracture. Eleven patients with malunited distal radius fracture underwent multislice CT of both wrists. A preoperative workup was performed in a virtual reality environment created from the CT data sets. Virtual planning comprised three main procedures, carrying out the virtual osteotomy of the radius, prediction of the final position of the distal radius after osteotomy and computer-assisted manufacturing of a repositioning device, which was later placed at the surgical osteotomy site to reposition objectively the distal radius fragment before fixation with the osteosynthesis. All patients tolerated the surgical procedure well. During surgery, the orthopedic surgeons were not required in any of the cases to alter the position of the distal radius that was determined by the repositioning device. At postoperative follow-up, the anatomic relationship of the distal radius was restored (radial inclination, 21.4 ; volar tilt, 10.3 ; ulnar variance, 0.5 mm). Clinically, a significant improvement of pronation (P=0.012), supination (P=0.01), flexion (P=0.001) and extension (P=0.006) was achieved. Pain decreased from 54 to 7 points. CT virtual reality is a valuable adjunct for the preoperative workup and surgical reposition of malunited distal radius fractures. (orig.)
Studying the proton 'radius' puzzle with μp elastic scattering
International Nuclear Information System (INIS)
Gilman, R.
2013-01-01
The disagreement between the proton radius determined from muonic hydrogen and from electronic measurements is called the proton radius puzzle. The resolution of the puzzle remains unclear and appears to require new experimental results. An experiment to measure muon-proton elastic scattering is presented here
Non union of the neck of radius: a case report and review of the ...
African Journals Online (AJOL)
Fractures of the neck of radius are frequent in trauma. They happen without being noticed at the moment of injury of the elbow or in the context of polytrauma. A case of non union of the radius neck occurring in a young person due to ignorance, during first consultation has been reported by the authors. They insist on the ...
Gradl, Gertraud; Neuhaus, Valentin; Fuchsberger, Thomas; Guitton, Thierry G.; Prommersberger, Karl-Josef; Ring, David; Wahegaonkar, Abhijeet L.; Shafritz, Adam B.; Garcia, Aida E.; Caputo, Andrew E.; Terrono, Andrew L.; Spoor, Andy B.; Eschler, Anica; Vochteloo, Anne J. H.; Beumer, Annechien; Barquet, Antonio; Kristan, Anze; van der Zwan, Arnard L.; Berner, Arne; Ilyas, Asif; Jubel, Axel; Sutker, Ben; Nolan, Betsy M.; Petrisor, Brad; Cross, Brian J.; Wills, Brian P. D.; Barreto, Camilo J. R.; Fernandes, Carlos H.; Swigart, Carrie; Zalavras, Charalampos; Goldfarb, Charles A.; Cassidy, Charles; Eaton, Charles; Wilson, Chris; Cheng, Christine J.; Wall, Christopher J.; Walsh, Christopher J.; Jones, Christopher M.; Garnavos, Christos; Klostermann, Cyrus; Kirkpatrick, D. Kay; Eygendaal, Denise; Verbeek, Diederik O. F.; Beeres, Frank J. P.; Thomas, George; Ponsen, Kornelis J.; van den Bekerom, Michel P. J.; Schep, Niels; Kloen, Peter; Haverlag, Robert
2013-01-01
To evaluate the reliability and accuracy of diagnosis of scapholunate dissociation (SLD) among AO type C (compression articular) fractures of the distal radius. A total of 217 surgeons evaluated 21 sets of radiographs with type C fractures of the distal radius for which the status of the
[Matrimonial radius and anthropologic differentiation of the population of the Peloponnese, Greece].
Pitsios, T K
1983-09-01
Mean matrimonial radius (MMR) and mean breeding radius (MBR) were studied in the population of the Peloponnese (Greece). The historical and geographical causes of these important genetical variables are discussed considering, too, their effects on the anthropological differentiation of this population.
Relationship between plate removal and Soong grading following surgery for fractured distal radius
Selles, Caroline A.; Reerds, Sam T. H.; Roukema, Gert; van der Vlies, Kees H.; Cleffken, Berry I.; Schep, Niels W. L.
2018-01-01
The aim of this study was to determine the relationship between volar plate removal and the Soong classification following fixation for fractured distal radius. In this retrospective cohort study, all consecutive patients who had volar plate fixation for a distal radius fracture in 2011-2015 were
M.A.M. Mulders (Marjolein A. M.); D. Rikli; J.C. Goslings (Carel); N.W.L. Schep (Niels)
2017-01-01
textabstractPurpose: Classification, the definition of an acceptable reduction and indications for surgery in distal radius fracturemanagement are still subject of debate. The purpose of this study was to characterise current distal radius fracture management in Europe. Methods: During the European
Vertical profiles of droplet effective radius in shallow convective clouds
Directory of Open Access Journals (Sweden)
S. Zhang
2011-05-01
Full Text Available Conventional satellite retrievals can only provide information on cloud-top droplet effective radius (r_{e}. Given the fact that cloud ensembles in a satellite snapshot have different cloud-top heights, Rosenfeld and Lensky (1998 used the cloud-top height and the corresponding cloud-top r_{e} from the cloud ensembles in the snapshot to construct a profile of r_{e} representative of that in the individual clouds. This study investigates the robustness of this approach in shallow convective clouds based on results from large-eddy simulations (LES for clean (aerosol mixing ratio N_{a} = 25 mg^{−1}, intermediate (N_{a} = 100 mg^{−1}, and polluted (N_{a} = 2000 mg^{−1} conditions. The cloud-top height and the cloud-top r_{e} from the modeled cloud ensembles are used to form a constructed r_{e} profile, which is then compared to the in-cloud r_{e} profiles. For the polluted and intermediate cases where precipitation is negligible, the constructed r_{e} profiles represent the in-cloud r_{e} profiles fairly well with a low bias (about 10 %. The method used in Rosenfeld and Lensky (1998 is therefore validated for nonprecipitating shallow cumulus clouds. For the clean, drizzling case, the in-cloud r_{e} can be very large and highly variable, and quantitative profiling based on cloud-top r_{e} is less useful. The differences in r_{e} profiles between clean and polluted conditions derived in this manner are however, distinct. This study also investigates the subadiabatic characteristics of the simulated cumulus clouds to reveal the effect of mixing on r_{e} and its evolution. Results indicate that as polluted and moderately polluted clouds develop into their decaying stage, the subadiabatic fraction
Stochastic theory of grain growth
International Nuclear Information System (INIS)
Hu Haiyun; Xing Xiusan.
1990-11-01
The purpose of this note is to set up a stochastic theory of grain growth and to derive the statistical distribution function and the average value of the grain radius so as to match them with the experiment further. 8 refs, 1 fig
Directory of Open Access Journals (Sweden)
Mehdi Safari
2016-09-01
Full Text Available In this work, laser forming of cylindrical surfaces with arbitrary radius of curvature is investigated experimentally and numerically. For laser forming of cylindrical surfaces with arbitrary radius of curvature, a new and comprehensive method is proposed in this paper. This method contains simple linear irradiating lines and using an analytical method, required process parameters for laser forming of a cylindrical surface with a specific radius of curvature is proposed. In this method, laser output power, laser scanning speed and laser beam diameter are selected based on laser machine and process limitations. As in the laser forming of a cylindrical surface, parallel irradiating lines are needed; therefore key parameter for production of a cylindrical surface with a specific radius of curvature is the number of irradiating lines. Hence, in the proposed analytical method, the required number of irradiating lines for production of a cylindrical surface with a specific radius of curvature is suggested. Performance of the proposed method for production of cylindrical surface with a specific radius of curvature is verified with experimental tests. The results show that using proposed analytical method, cylindrical surfaces with any radius of curvature can be produced successfully.
The radius of the quiescent neutron star in the globular cluster M13
Shaw, A. W.; Heinke, C. O.; Steiner, A. W.; Campana, S.; Cohn, H. N.; Ho, W. C. G.; Lugger, P. M.; Servillat, M.
2018-06-01
X-ray spectra of quiescent low-mass X-ray binaries containing neutron stars can be fit with atmosphere models to constrain the mass and the radius. Mass-radius constraints can be used to place limits on the equation of state of dense matter. We perform fits to the X-ray spectrum of a quiescent neutron star in the globular cluster M13, utilizing data from ROSAT, Chandra, and XMM-Newton, and constrain the mass-radius relation. Assuming an atmosphere composed of hydrogen and a 1.4 M⊙ neutron star, we find the radius to be R_NS=12.2^{+1.5}_{-1.1} km, a significant improvement in precision over previous measurements. Incorporating an uncertainty on the distance to M13 relaxes the radius constraints slightly and we find R_NS=12.3^{+1.9}_{-1.7} km (for a 1.4M⊙ neutron star with a hydrogen atmosphere), which is still an improvement in precision over previous measurements, some of which do not consider distance uncertainty. We also discuss how the composition of the atmosphere affects the derived radius, finding that a helium atmosphere implies a significantly larger radius.
Synchronous Multicentric Giant Cell Tumour of Distal Radius and Sacrum with Pulmonary Metastases
Directory of Open Access Journals (Sweden)
Varun Sharma Tandra
2015-01-01
Full Text Available Giant cell tumour (GCT is an uncommon primary bone tumour, and its multicentric presentation is exceedingly rare. We report a case of a 45-year-old female who presented to us with GCT of left distal radius. On the skeletal survey, osteolytic lesion was noted in her right sacral ala. Biopsy confirmed both lesions as GCT. Pulmonary metastasis was also present. Resection-reconstruction arthroplasty for distal radius and thorough curettage and bone grafting of the sacral lesion were done. Multicentric GCT involving distal radius and sacrum with primary sacral involvement is not reported so far to our knowledge.
Correction of the exciton Bohr radius in monolayer transition metal dichalcogenides
Li, Run-Ze; Dong, Xi-Ying; Li, Zhi-Qing; Wang, Zi-Wu
2018-07-01
We theoretically investigate the correction of exciton Bohr radius in monolayer transition metal dichalcogenides (TMDCs) on different polar substrates arising from the exciton-optical phonon coupling, in which both the intrinsic longitudinal optical phonon and surface optical phonon modes couple with the exciton are taken into account. We find that the exciton Bohr radius is enlarged markedly due to these coupling. Moreover, it can be changed on a large scale by modulating the polarizability of polar substrate and the internal distance between the monolayer TMDCs and polar substrate. Theoretical result provides a potential explanation for the variation of the exciton Bohr radius in experimental measurement.
Initialization effects via the nuclear radius on transverse in-plane flow and its disappearance
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Bansal Rajni
2014-04-01
Full Text Available We study the dependence of collective transverse flow and its disappearance on initialization effects via the nuclear radius within the framework of the Isospin-dependent Quantum Molecular Dynamics (IQMD model. We calculate the balance energy using different parametrizations of the radius available in the literature for the reaction of 12C+12C to explain its measured balance energy. A mass-dependent analysis of the balance energy through out the periodic table is also carried out by changing the default liquid drop IQMD radius.
X-ray Spectroscopy of the Virgo Cluster out to the Virial Radius
Urban, O.; Werner, N.; Simionescu, A.; Allen, S. W.; Böhringer, H.
2011-01-01
We present results from the analysis of a mosaic of thirteen XMM-Newton pointings covering the Virgo Cluster from its center northwards out to a radius r~1.2 Mpc (~4.5 degrees), reaching the virial radius and beyond. This is the first time that the properties of a modestly sized (M_vir~1.4e14 M_sun, kT~2.3 keV), dynamically young cluster have been studied out to the virial radius. The density profile of the cluster can be described by a surprisingly shallow power-law with index 1.21+/-0.12. I...
Initialization effects via the nuclear radius on transverse in-plane flow and its disappearance
International Nuclear Information System (INIS)
Bansal, Rajni; Gautam, Sakshi
2014-01-01
We study the dependence of collective transverse flow and its disappearance on initialization effects via the nuclear radius within the framework of the Isospin-dependent Quantum Molecular Dynamics (IQMD) model. We calculate the balance energy using different parametrizations of the radius available in the literature for the reaction of 12 C + 12 C to explain its measured balance energy. A mass-dependent analysis of the balance energy through out the periodic table is also carried out by changing the default liquid drop IQMD radius. (author)
Directory of Open Access Journals (Sweden)
Hiroshi Tatewaki
2015-06-01
Full Text Available We consider, for atoms from 55Cs to 80Hg, the effective atomic radius (rear, which is defined as the distance from the nucleus at which the magnitude of the electric field is equal to that in He at one half of the equilibrium bond length of He2. The values of rear are about 50% larger than the mean radius of the outermost occupied orbital of 6s, . The value of rear decreases from 55Cs to 56Ba and undergoes increases and decreases with rising nuclear charge from 57La to 70Y b. In fact rear is understood as comprising two interlaced sequences; one consists of 57La, 58Ce, and 64Gd, which have electronic configuration (4fn−1(5d1(6s2, and the remaining atoms have configuration (4fn(6s2. The sphere defined by rear contains 85%–90% of the 6s electrons. From 71Lu to 80Hg the radius rear also involves two sequences, corresponding to the two configurations 5dn+16s1 and 5dn6s2. The radius rear according to the present methodology is considerably larger than rvdW obtained by other investigators, some of who have found values of rvdW close to .
Bayesian Analysis of Hot-Jupiter Radius Anomalies: Evidence for Ohmic Dissipation?
Thorngren, Daniel P.; Fortney, Jonathan J.
2018-05-01
The cause of hot-Jupiter radius inflation, where giant planets with {T}eq} > 1000 K are significantly larger than expected, is an open question and the subject of many proposed explanations. Many of these hypotheses postulate an additional anomalous power that heats planets’ convective interiors, leading to larger radii. Rather than examine these proposed models individually, we determine what anomalous powers are needed to explain the observed population’s radii, and consider which models are most consistent with this. We examine 281 giant planets with well-determined masses and radii and apply thermal evolution and Bayesian statistical models to infer the anomalous power as a fraction of (and varying with) incident flux ɛ(F) that best reproduces the observed radii. First, we observe that the inflation of planets below about M = 0.5 M J appears very different than their higher-mass counterparts, perhaps as the result of mass loss or an inefficient heating mechanism. As such, we exclude planets below this threshold. Next, we show with strong significance that ɛ(F) increases with {T}eq} toward a maximum of ∼2.5% at T eq ≈ 1500 K, and then decreases as temperatures increase further, falling to ∼0.2% at T eff = 2500 K. This high-flux decrease in inflation efficiency was predicted by the Ohmic dissipation model of giant planet inflation but not other models. We also show that the thermal tides model predicts far more variance in radii than is observed. Thus, our results provide evidence for the Ohmic dissipation model and a functional form for ɛ(F) that any future theories of hot-Jupiter radii can be tested against.
Gyrokinetic theory of perpendicular cyclotron resonance in a nonuniformly magnetized plasma
International Nuclear Information System (INIS)
Lashmore-Davies, C.N.; Dendy, R.O.
1989-01-01
The extension of gyrokinetic theory to arbitrary frequencies by Chen and Tsai [Phys. Fluids 26, 141 (1983); Plasma Phys. 25, 349 (1983)] is used to study cyclotron absorption in a straight magnetic field with a perpendicular, linear gradient in strength. The analysis includes the effects of magnetic field variation across the Larmor orbit and is restricted to propagation perpendicular to the field. It yields the following results for propagation into the field gradient. The standard optical depths for the fundamental O-mode and second harmonic X-mode resonances are obtained from the absorption profiles given in this paper, without invoking relativistic mass variation [see also Antonsen and Manheimer, Phys. Fluids 21, 2295 (1978)]. The compressional Alfven wave is shown to undergo perpendicular cyclotron damping at the fundamental minority resonance in a two-ion species plasma and at second harmonic resonance in a single-ion species plasma. Ion Bernstein waves propagating into the second harmonic resonance are no longer unattenuated, but are increasingly damped as they approach the resonance. It is shown how the kinetic power flow affects absorption profiles, yielding information previously obtainable only from full-wave theory. In all cases, the perpendicular cyclotron damping arises from the inclusion of magnetic field variation across the Larmor orbit
Modification of ELESTRES code with new database of flux depression across the pellet radius
International Nuclear Information System (INIS)
Sim, Ki Sub; Park, Kwang Suk; Byun, Taek Sang; Suk, Ho Chun
1995-01-01
Modification of ELESTRES CANDU fuel performance code with new database of flux depression across the pellet radius is described, and application results of the improved ELESTRES to the fuel performance data are described. (Author) 4 refs., 4 figs
Sun, Chuanzhi; Wang, Lei; Tan, Jiubin; Zhao, Bo; Tang, Yangchao
2016-02-01
The paper designs a roundness measurement model with multi-systematic error, which takes eccentricity, probe offset, radius of tip head of probe, and tilt error into account for roundness measurement of cylindrical components. The effects of the systematic errors and radius of components are analysed in the roundness measurement. The proposed method is built on the instrument with a high precision rotating spindle. The effectiveness of the proposed method is verified by experiment with the standard cylindrical component, which is measured on a roundness measuring machine. Compared to the traditional limacon measurement model, the accuracy of roundness measurement can be increased by about 2.2 μm using the proposed roundness measurement model for the object with a large radius of around 37 mm. The proposed method can improve the accuracy of roundness measurement and can be used for error separation, calibration, and comparison, especially for cylindrical components with a large radius.
National Research Council Canada - National Science Library
Crane, Lynn
2000-01-01
... a region, is a system that meets the Remote Authentication Dial-In User Service (RADIUS) standard. This report describes the development and trials of the technology and provides an analysis of alternative.
Directory of Open Access Journals (Sweden)
Katerina Katerina Kasapinova
2014-06-01
CONCLUSIONS: The frequency of the associated soft-tissue lesions in distal radius fractures is high. Ulnar styloid fracture was identified as risk factor for associated LT lesion, as well as combined lesion of both scapholunate and luntriquetral ligament.
Exact solution of gyration radius of individual's trajectory for a simplified human mobility model
Yan, Xiao-Yong; Han, Xiao-Pu; Zhou, Tao; Wang, Bing-Hong
2010-01-01
Gyration radius of individual's trajectory plays a key role in quantifying human mobility patterns. Of particular interests, empirical analyses suggest that the growth of gyration radius is slow versus time except the very early stage and may eventually arrive to a steady value. However, up to now, the underlying mechanism leading to such a possibly steady value has not been well understood. In this Letter, we propose a simplified human mobility model to simulate individual's daily travel wit...
LENUS (Irish Health Repository)
Bahari, Syah
2007-07-01
Fracture of the distal radius from low energy trauma is a common presentation to orthopaedic trauma services. This fragility type fracture is associated with underlying osteoporosis. Osteoporosis is a \\'silent disease\\' where fragility fracture is a common presentation. Orthopaedic surgeons may be the only physician that these patients encounter. We found a high percentage of female patients who sustained a fragility fracture of the distal radius have an underlying osteoporosis. Further management of osteoporosis is important to prevent future fragility fractures.
Study on Oneself Developed to Apparatus Position of Measurement of BMD in the Distal Radius
International Nuclear Information System (INIS)
Han, Man Seok; Song, Jae Yong; Lee, Hyun Kuk; Yu, Se Jong; Kim, Yong Kyun
2009-01-01
The aim of this study was to evaluate the difference of bone mineral density according to distal radius rotation and to develop the supporting tool to measure rotation angles. CT scanning and the measurement of BMD by DXA of the appropriate position of the forearm were performed on 20 males. Twenty healthy volunteers without any history of operations, anomalies, or trauma were enrolled. The CT scan was used to evaluate the cross sectional structure and the rotation angle on the horizontal plane of the distal radius. The rotational angle was measured by the m-view program on the PACS monitor. The DXA was used in 20 dried radii of cadaveric specimens in pronation and supination with five and ten degrees, respectively, including a neutral position (zero degrees) to evaluate the changes of BMD according to the rotation. The mean rotation angle of the distal radius on CT was 7.4 degrees of supination in 16 cases (80%), 3.3 degrees of pronation in three cases (15%), and zero degree of neutral in one case (9%), respectively. The total average rotation angle in 20 people was 5.4 degrees of supination. In the cadaveric study, the BMD of the distal radius was different according to the rotational angles. The lowest BMD was obtained at 3.3 degrees of supination. In the case of the measurement of BMD in the distal radius with a neutral position, the rotational angle of the distal radius is close to supination. Pronation is needed for the constant measurement of BMD in the distal radius with the rotation angle measuring at the lowest BMD and about five degrees of pronation of the distal radius is recommended.
The mean free path of protons in nuclei and the nuclear radius
International Nuclear Information System (INIS)
Dymarz, R.; Kohmura, T.
1983-01-01
We determine the mean free path of protons in nuclei in the energy range 40-1000 MeV. We find that it is necessary to use in the calculation of the mean free path the nuclear radius R which reproduces the reaction and total cross sections consistently and that this radius leads to a rather small mean free path which is comparable with the value obtained in the microscopic calculation in the whole energy region. (orig.)
International Nuclear Information System (INIS)
Zhu Shoupeng; Wang Liuyi; Cao Genfa; Sun Baofu
1991-05-01
The purpose of the present study was to ascertain the correlation between the different ionic radius of rare earths nuclides such as 170 Tm, 152 Eu, 147 Pm and its accumulation peculiarity as well as induction of mutagenic effect on bone marrow cells. The study showed that the accumulation peculiarity of rare earths nuclides will vary with the ionic radius. The results indicated that large ionic radius of 147 Pm was selectively localized in liver in early stage, while small ionic radius of 170 Tm and 152 Eu were deposited in bone predominantly. There was a positive relationship between the incidence of chromosome aberration rates and the absorption dose in skeleton by 170 Tm, 152 Eu, or 147 Pm. Studies indicated that the chromosome aberration rates were elevated when the absorption dose in skeleton was increased. Among the type of chromosome aberrations induced by rare earths nuclides with different ionic radius, chromatid breakage was predominant, accompanied with a few chromosome breakage and translocation. At the same time mitosis index of metaphase cells was depressed. Internal contamination of 170 Tm, 152 Eu, or 147 Pm can be induced by some aberrations in one cell. This phenomenon might be due in part to nonuniform irradiation of bone marrow cell with local deposition of these rare earths nuclides with different ionic radius
Does bone measurement on the radius indicate skeletal status. Concise communication
International Nuclear Information System (INIS)
Mazess, R.B.; Peppler, W.W.; Chesney, R.W.; Lange, T.A.; Lindgren, U.; Smith, E. Jr.
1984-01-01
Single-photon (I-125) absorptiometry was used to measure bone mineral content (BMC) of the distal third of the radius, and dual-photon absorptiometry (Gd-153) was used to measure total-body bone mineral (TBBM), as well as the BMC of major skeletal regions. Measurements were done in normal females, normal males, osteoporotic females, osteoporotic males, and renal patients. The BMC of the radius predicted TBBM well in normal subjects, but was less satisfactory in the patient groups. The spinal BMC was predicted with even lower accuracy from radius measurement. The error in predicting areal density (bone mass per unit projected skeletal area) of the lumbar and thoracic spine from the radius BMC divided by its width was smaller, but the regressions differed significantly among normals, osteoporotics, and renal patients. There was a preferential spinal osteopenia in the osteoporotic group and in about half of the renal patients. Bone measurements on the radius can indicate overall skeletal status in normal subjects and to a lesser degree in patients, but these radius measurements are inaccurate, even on the average, as an indicator of spinal state
Effects of corner radius on periodic nanoantenna for surface-enhanced Raman spectroscopy
International Nuclear Information System (INIS)
Chao, Bo-Kai; Lin, Shih-Che; Nien, Li-Wei; Hsueh, Chun-Hway; Li, Jia-Han
2015-01-01
Corner radius is a concept to approximate the fabrication limitation due to the effective beam broadening at the corner in using electron-beam lithography. The purpose of the present study is to investigate the effects of corner radius on the electromagnetic field enhancement and resonance wavelength for three periodic polygon dimers of bowtie, twin square, and twin pentagon. The enhancement factor of surface-enhanced Raman spectroscopy due to the localized surface plasmon resonances in fabricated gold bowtie nanostructures was investigated using both Raman spectroscopy and finite-difference time-domain simulations. The simulated enhancement factor versus corner radius relation was in agreement with measurements and it could be fitted by a power-law relation. In addition, the resonance wavelength showed blue shift with the increasing corner radius because of the distribution of concentrated charges in a larger area. For different polygons, the corner radius instead of the tip angle is the dominant factor of the electromagnetic field enhancement because the surface charges tend to localize at the corner. Greater enhancements can be obtained by having both the smaller gap and sharper corner although the corner radius effect on intensity enhancement is less than the gap size effect. (paper)
Synthetical optimization of hydraulic radius and acoustic field for thermoacoustic cooler
International Nuclear Information System (INIS)
Kang Huifang; Li Qing; Zhou Gang
2009-01-01
It is well known that the acoustic field and the hydraulic radius of the regenerator play key roles in thermoacoustic processes. The optimization of hydraulic radius strongly depends on the acoustic field in the regenerator. This paper investigates the synthetical optimization of hydraulic radius and acoustic field which is characterized by the ratio of the traveling wave component to the standing wave component. In this paper, we discussed the heat flux, cooling power, temperature gradient and coefficient of performance of thermoacoustic cooler with different combinations of hydraulic radiuses and acoustic fields. The calculation results show that, in the cooler's regenerator, due to the acoustic wave, the heat is transferred towards the pressure antinodes in the pure standing wave, while the heat is transferred in the opposite direction of the wave propagation in the pure traveling wave. The better working condition for the regenerator appears in the traveling wave phase region of the like-standing wave, where the directions of the heat transfer by traveling wave component and standing wave component are the same. Otherwise, the small hydraulic radius is not a good choice for acoustic field with excessively high ratio of traveling wave, and the small hydraulic radius is only needed by the traveling wave phase region of like-standing wave.
Influence of radius of cylinder HTS bulk on guidance force in a maglev vehicle system
International Nuclear Information System (INIS)
Longcai, Zhang
2014-01-01
Highlights: • The guidance force was decayed by the application of the AC external magnetic field. • The guidance force was higher for the bulk with bigger radius. • The guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. - Abstract: Bulk superconductors had great potential for various engineering applications, especially in a high-temperature superconducting (HTS) maglev vehicle system. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFeB guideway used in the HTS maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we investigated the influence of the radius of the cylinder HTS bulk exposed to an AC magnetic field perturbation on the guidance force in the maglev vehicle system. From the results, it was found that the guidance force was stronger for the bulk with bigger radius and the guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. Therefore, in order to obtain higher guidance force in the maglev vehicle system, we could use the cylinder HTS bulks with the bigger radius
[Growth behaviour after fractures of the proximal radius: differences to the rest of the skeleton].
Hell, A K; von Laer, L
2014-12-01
Fractures of the proximal end of the radius in the growth phase have three characteristics: the head of the radius articulates with two joint partners and is therefore indispensable for an undisturbed function of the elbow. The blood supply of the proximal end of the radius is via periosteal vessels in the sense of a terminal circulation which makes it extremely vulnerable. Severe trauma caused either by accidents or treatment, can result in partial or complete necrosis with deformity of the head and neck region of the radius. Radioulnar synostosis and chronic epiphysiolysis are irreversible complications which can occur after excessive physiotherapy. Despite a low potency growth plate, in young patients the proximal end of the radius shows an enormous spontaneous correction of dislocations. Side to side shifts, however, will not be remodeled. Therapy should be as atraumatic as possible. Due to the blood supply situation, with the appropriate indications the spontaneous correction and a brief period of immobilization without physiotherapy should be integrated into the therapy concept. If an operation is necessary, repeated traumatic repositioning maneuvers should be avoided and in case of doubt closed or careful open repositioning can be achieved with intramedullary nailing. In order to take the special characteristics of the proximal radius into consideration, the vulnerability and correction potential must be weighed up against each other. Therapy must be as atraumatic as possible. The spontaneous correction potential should be integrated into the primary therapy without overestimating this potential with respect to the extent and age of the patient.
Solar Radius at Subterahertz Frequencies and Its Relation to Solar Activity
Menezes, Fabian; Valio, Adriana
2017-12-01
The Sun emits radiation at several wavelengths of the electromagnetic spectrum. In the optical band, the solar radius is 695 700 km, and this defines the photosphere, which is the visible surface of the Sun. However, as the altitude increases, the electromagnetic radiation is produced at other frequencies, causing the solar radius to change as a function of wavelength. These measurements enable a better understanding of the solar atmosphere, and the radius dependence on the solar cycle is a good indicator of the changes that occur in the atmospheric structure. We measure the solar radius at the subterahertz frequencies of 0.212 and 0.405 THz, which is the altitude at which these emissions are primarily generated, and also analyze the radius variation over the 11-year solar activity cycle. For this, we used radio maps of the solar disk for the period between 1999 and 2017, reconstructed from daily scans made by the Solar Submillimeter-wave Telescope (SST), installed at El Leoncito Astronomical Complex (CASLEO) in the Argentinean Andes. Our measurements yield radii of 966.5'' ±2.8'' for 0.2 THz and 966.5'' ±2.7'' for 0.4 THz. This implies a height of 5.0 ±2.0 ×106 m above the photosphere. Furthermore, we also observed a strong anticorrelation between the radius variation and the solar activity at both frequencies.
Influence of radius of cylinder HTS bulk on guidance force in a maglev vehicle system
Energy Technology Data Exchange (ETDEWEB)
Longcai, Zhang, E-mail: zhlcai2000@163.com
2014-07-15
Highlights: • The guidance force was decayed by the application of the AC external magnetic field. • The guidance force was higher for the bulk with bigger radius. • The guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. - Abstract: Bulk superconductors had great potential for various engineering applications, especially in a high-temperature superconducting (HTS) maglev vehicle system. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFeB guideway used in the HTS maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we investigated the influence of the radius of the cylinder HTS bulk exposed to an AC magnetic field perturbation on the guidance force in the maglev vehicle system. From the results, it was found that the guidance force was stronger for the bulk with bigger radius and the guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. Therefore, in order to obtain higher guidance force in the maglev vehicle system, we could use the cylinder HTS bulks with the bigger radius.
Directory of Open Access Journals (Sweden)
Harumi Nakayama
2018-03-01
Full Text Available Objectives: As clinics that treat patients with osteoporosis do not usually have central dual-energy X-ray absorptiometry (DXA, bone density is often measured with radial DXA. However, no long-term evidence exists for radius bone density outcomes following treatment with once-weekly teriparatide in actual medical treatment. Methods: We evaluated changes in bone density at 6-, 12-, and 18-month intervals using radial DXA in patients treated with once-weekly teriparatide for more than 6 months. Results: A significant increase in bone mineral density (BMD was observed at the 1/3 and 1/10 radius sites 12 months after the initiation of once-weekly teriparatide. We also observed that the rate of change in BMD was greater at the distal 1/10 radius than at the 1/3 radius. Conclusions: Considering these points, the effect of once-weekly teriparatide therapy can be observed at the radius. In clinics that do not have central DXA, but instead have radial DXA, these findings can help to evaluate the effect of once-weekly teriparatide treatment on osteoporosis. Keywords: Once-weekly teriparatide, Osteoporosis, Radius, Dual-energy X-ray absorptiometry
Topological methods in gauge theory
International Nuclear Information System (INIS)
Sarukkai, S.R.
1992-01-01
The author begins with an overview of the important topological methods used in gauge theory. In the first chapter, the author discusses the general structure of fiber bundles and associated mathematical concepts and briefly discuss their application in gauge theory. The second chapter deals with the study of instantons in both gauge and gravity theories. These self-dual solutions are presented. This chapter is also a broad introduction to certain topics in gravitational physics. Gravity and gauge theory are unified in Kaluza-Klein theory as discussed in the third chapter. Of particular interest is the physics of the U(1) bundles over non-trivial manifolds. The radius of the fifth dimension is undetermined classically in the Kaluza-Klein theory. A mechanism is described using topological information to derive the functional form of the radius of the fifth dimension and show that it is possible classically to derive expressions for the radius as a consequence of topology. The behavior of the radius is dependent on the information present in the base metric. Results are computed for three gravitational instantons. Consequences of this mechanism are discussed. The description is studied of instantons in terms of projector valued fields and universal bundles. The results of the previous chapter and this are connected via the study of universal bundles. Projector valued transformations are defined and their consequences discussed. With the solutions of instantons in this formalism, it is shown explicitly that there can be solutions which allow for a Sp(n) instanton to be transformed to a Sp(k) instanton, thus showing that there can be interpolations which carry one instanton with a rank n to another characterized by rank k with different topological numbers
The White-Dwarf Mass-Radius Relation from 40 Eridani B and Other Nearby Visual Binaries
Bond, Howard E.; Bergeron, P.; Bedard, A.
2018-01-01
The bright, nearby DA-type white dwarf (WD) 40 Eridani B is orbited by the M dwarf 40 Eri C, allowing determination of the WD's mass. Until recently, however, the mass depended on orbital elements determined four decades ago, and that mass was so low that it created several astrophysical puzzles. Using new astrometric measurements, the binary-star group at the U.S. Naval Observatory has revised the dynamical mass upward, to 0.573 ± 0.018 M⊙. We have used model-atmosphere analysis to update other parameters of the WD, including effective temperature, surface gravity, radius, and luminosity. We then comparethese results with WD interior models.Within the observational uncertainties, theoretical cooling tracks for CO-core WDs of its measured mass are consistent with the position of 40 Eri B in the H-R diagram; equivalently, the theoretical mass-radius relation (MRR) is consistent with the star's location in the mass-radius plane. This consistency is, however, achieved only if we assume a "thin'' outer hydrogen layer, with qH = MH/MWD ∼ 10–10.We discuss other evidence that a significant fraction of DA WDs have such thin H layers, in spite of expectation from canonical stellar-evolution theory of "thick'' H layers with qH ∼ 10–4 . The cooling age of 40 Eri B is ~122 Myr, and its total age is ~1.8 Gyr. We present the MRRs for 40 Eri B and three other nearby WDs in visual binaries with precise mass determinations, and show that the agreement of current theory with observation is excellent in all cases.However, astrophysical puzzles remain. The eccentricity of the BC orbit has remained high (0.43), even though the progenitor of B ought to have interacted tidally with C when it was an AGB star. This puzzle exists also for the Sirius and Procyon systems. If thin hydrogen layers are common among WDs, the mass scale will need to be shifted downwards by a few hundredths of a solar mass.
Energy Technology Data Exchange (ETDEWEB)
Tatewaki, Hiroshi, E-mail: htatewak@nsc.nagoya-cu.ac.jp [Graduate School of Natural Sciences, Nagoya City University, Nagoya, Aichi 467-8501 (Japan); Institute of Advanced Studies in Artificial Intelligence, Chukyo University, Toyota, Aichi 470-0393 (Japan); Hatano, Yasuyo [School of Information Science and Technology, Chukyo University, Toyota, Aichi 470-0393 (Japan); Noro, Takeshi [Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Yamamoto, Shigeyoshi [School of International Liberal Studies, Chukyo University, Nagoya, Aichi 466-8666 (Japan)
2015-06-15
We consider, for atoms from {sub 55}Cs to {sub 80}Hg, the effective atomic radius (r{sub ear}), which is defined as the distance from the nucleus at which the magnitude of the electric field is equal to that in He at one half of the equilibrium bond length of He{sub 2}. The values of r{sub ear} are about 50% larger than the mean radius of the outermost occupied orbital of 6s,
Space Inside a Liquid Sphere Transforms into De Sitter Space by Hilbert Radius
Rabounski, Dmitri; Borissova, Larissa
2010-04-01
Consider space inside a sphere of incompressible liquid, and space surrounding a mass-point. Metrics of the spaces were deduced in 1916 by Karl Schwarzschild. 1) Our calculation shows that a liquid sphere can be in the state of gravitational collapse (g00 = 0) only if its mass and radius are close to those of the Universe (M = 8.7x10^55 g, a = 1.3x10^28 cm). However if the same mass is presented as a mass-point, the radius of collapse rg (Hilbert radius) is many orders lesser: g00 = 0 realizes in a mass-point's space by other conditions. 2) We considered a liquid sphere whose radius meets, formally, the Hilbert radius of a mass-point bearing the same mass: a = rg, however the liquid sphere is not a collapser (see above). We show that in this case the metric of the liquid sphere's internal space can be represented as de Sitter's space metric, wherein λ = 3/a^2 > 0: physical vacuum (due to the λ-term) is the same as the field of an ideal liquid where ρ0 0 (the mirror world liquid). The gravitational redshift inside the sphere is produced by the non-Newtonian force of repulsion (which is due to the λ-term, λ = 3/a^2 > 0); it is also calculated.
Bounds of the Spectral Radius and the Nordhaus-Gaddum Type of the Graphs
Directory of Open Access Journals (Sweden)
Tianfei Wang
2013-01-01
Full Text Available The Laplacian spectra are the eigenvalues of Laplacian matrix L(G=D(G-A(G, where D(G and A(G are the diagonal matrix of vertex degrees and the adjacency matrix of a graph G, respectively, and the spectral radius of a graph G is the largest eigenvalue of A(G. The spectra of the graph and corresponding eigenvalues are closely linked to the molecular stability and related chemical properties. In quantum chemistry, spectral radius of a graph is the maximum energy level of molecules. Therefore, good upper bounds for the spectral radius are conducive to evaluate the energy of molecules. In this paper, we first give several sharp upper bounds on the adjacency spectral radius in terms of some invariants of graphs, such as the vertex degree, the average 2-degree, and the number of the triangles. Then, we give some numerical examples which indicate that the results are better than the mentioned upper bounds in some sense. Finally, an upper bound of the Nordhaus-Gaddum type is obtained for the sum of Laplacian spectral radius of a connected graph and its complement. Moreover, some examples are applied to illustrate that our result is valuable.
The white dwarf mass-radius relation with Gaia, Hubble and FUSE
Joyce, Simon R. G.; Barstow, Martin A.; Casewell, Sarah L.; Holberg, Jay B.; Bond, Howard E.
2018-04-01
White dwarfs are becoming useful tools for many areas of astronomy. They can be used as accurate chronometers over Gyr timescales. They are also clues to the history of star formation in our galaxy. Many of these studies require accurate estimates of the mass of the white dwarf. The theoretical mass-radius relation is often invoked to provide these mass estimates. While the theoretical mass-radius relation is well developed, observational tests of this relation show a much larger scatter in the results than expected. High precision observational tests to confirm this relation are required. Gaia is providing distance measurements which will remove one of the main source of uncertainty affecting most previous observations. We combine Gaia distances with spectra from the Hubble and FUSE satelites to make precise tests of the white dwarf mass-radius relation.
Measurements of the Minimum Bending Radius of Small Diameter Scintillating Plastic Fibres
Gruber, Lukas; Vaananen, Mika Petteri; Gavardi, Laura
2018-01-01
The minimum bending radius of plastic fibres is an important parameter as it determines the geometrical flexibility of the fibres during long-term storage or installation and usage inside detectors. The following document describes measurements of the minimum bending radius of round scintillating plastic fibres with small diameter performed in the context of the LHCb SciFi Tracker project. The experimental set-up is based on measuring the light output of a bent fibre in response to 1 MeV electrons over several days. The results suggest that the 250 μm diameter fibres can be bent to a radius of about 10 mm without damaging and losing light.
Directory of Open Access Journals (Sweden)
Sanjeev Kumar Kare
2016-12-01
Full Text Available BACKGROUND Fracture of the distal radius (‘broken wrist’ is a common clinical problem. It can be treated conservatively usually involving wrist immobilisation in a plaster cast or surgically. A key method of surgical fixation is external fixation. MATERIALS AND METHODS A prospective study was carried out on 66 patients admitted between June 2014 to May 2016 for evaluation of conservative and surgical management of distal radius fractures. RESULTS Excellent, fair or good result was noticed in around 85% of cases managed conservatively and in above 90% of cases managed by external fixator. CONCLUSION There is some evidence to support the use of external fixation for dorsally displaced fractures of the distal radius in adults. Though, there is insufficient evidence to confirm a better functional outcome, external fixation reduces redisplacement gives improved anatomical results and most of the excess surgically-related complications are minor.
Possibility to determine the radius of accretion disk by gravitational waves
International Nuclear Information System (INIS)
Sotani, H; Saijo, M
2007-01-01
We investigate gravitational waves from a dust disk around a Schwarzschild black hole to focus on whether we can extract any of its physical properties from a direct detection of gravitational waves. We adopt a black hole perturbation approach in a time domain, which is a satisfactory approximation to illustrate a dust disk in a supermassive black hole. We find that we can determine the radius of the disk by using the power spectrum of gravitational waves and that our method to extract the radius works for a disk of arbitrary density distribution. Therefore we believe a possibility exists for determining the radius of the disk from a direct observation of gravitational waves detected by the Laser Interferometer Space Antenna
The Splashback Radius of Halos from Particle Dynamics. I. The SPARTA Algorithm
Diemer, Benedikt
2017-07-01
Motivated by the recent proposal of the splashback radius as a physical boundary of dark-matter halos, we present a parallel computer code for Subhalo and PARticle Trajectory Analysis (SPARTA). The code analyzes the orbits of all simulation particles in all host halos, billions of orbits in the case of typical cosmological N-body simulations. Within this general framework, we develop an algorithm that accurately extracts the location of the first apocenter of particles after infall into a halo, or splashback. We define the splashback radius of a halo as the smoothed average of the apocenter radii of individual particles. This definition allows us to reliably measure the splashback radii of 95% of host halos above a resolution limit of 1000 particles. We show that, on average, the splashback radius and mass are converged to better than 5% accuracy with respect to mass resolution, snapshot spacing, and all free parameters of the method.
Aplikasi Pencarian Tempat Wisata Berbasiskan GPS dengan Metode Radius dan Rating
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Budi Yulianto
2015-03-01
Full Text Available Tourist place navigation application becomes more important for travelers, especially backpackers. Previous research had produced applications which can only show the route from the position of traveler to tourist place with map shown. The goal of the research is to use the radius and rating method that is still rare in the community to navigate tourist place. Output of the research is a GPS-based application that can display the search results of tourist sites based on rating and radius method, route from the traveler to the destination place, and description of the place. Development method used waterfall that contained user requirement, analysis, design, coding and testing, implementation, and maintenance. Conclusion of the research has shown that the developed application provided convenience in searching tourist places based on radius and rating, displaying route, and description of tourist places.
Millimetre spectral indices of transition disks and their relation to the cavity radius
Pinilla, P.; Benisty, M.; Birnstiel, T.; Ricci, L.; Isella, A.; Natta, A.; Dullemond, C. P.; Quiroga-Nuñez, L. H.; Henning, T.; Testi, L.
2014-04-01
Context. Transition disks are protoplanetary disks with inner depleted dust cavities that are excellent candidates for investigating the dust evolution when there is a pressure bump. A pressure bump at the outer edge of the cavity allows dust grains from the outer regions to stop their rapid inward migration towards the star and to efficiently grow to millimetre sizes. Dynamical interactions with planet(s) have been one of the most exciting theories to explain the clearing of the inner disk. Aims: We look for evidence of millimetre dust particles in transition disks by measuring their spectral index αmm with new and available photometric data. We investigate the influence of the size of the dust depleted cavity on the disk integrated millimetre spectral index. Methods: We present the 3-mm (100 GHz) photometric observations carried out with the Plateau de Bure Interferometer of four transition disks: LkHα 330, UX Tau A, LRLL 31, and LRLL 67. We used the available values of their fluxes at 345 GHz to calculate their spectral index, as well as the spectral index for a sample of twenty transition disks. We compared the observations with two kinds of models. In the first set of models, we considered coagulation and fragmentation of dust in a disk in which a cavity is formed by a massive planet located at different positions. The second set of models assumes disks with truncated inner parts at different radii and with power-law dust-size distributions, where the maximum size of grains is calculated considering turbulence as the source of destructive collisions. Results: We show that the integrated spectral index is higher for transition disks (TD) than for regular protoplanetary disks (PD) with mean values of bar{αmmTD} = 2.70 ± 0.13 and bar{αmmPD} = 2.20 ± 0.07 respectively. For transition disks, the probability that the measured spectral index is positively correlated with the cavity radius is 95%. High angular resolution imaging of transition disks is needed to
Gao, Pengfei; Tian, Zijian; Wang, Xuqi; Wu, Jun; Gui, Weifeng
2018-03-01
Wireless power transfer (WPT) via coupled magnetic resonance is a promising technology to be applied in many fields. In general, there will be a radial gap in practical application, and some special application environments need to limit the radius of the coils. Therefore, in this paper, considering the comprehensive analysis of the radial gap and the radius of the coils, the concept of the ratio of radial gap to the radius of the coils was proposed. Based on the circuit theory, the formula between the ratio and transmission efficiency of WPT was deduced, and the effects of the ratio on the transmission efficiency were studied respectively at different axial distances. Simulation experiments were carried out and the results not only demonstrate the influence law of the ratio on transmission efficiency, but also validate the value of the ratio which the axial distance has the greatest effect on the transmission efficiency. Besides, the results shows the relationship between the effect of the ratio on the efficiency and the effect of the axial distance on the efficiency. The experimental results show that the theoretical analysis is correct, thus providing an useful theoretical reference for the design and further research on the wireless power transfer system in complicated environment.
Directory of Open Access Journals (Sweden)
Pengfei Gao
2018-03-01
Full Text Available Wireless power transfer (WPT via coupled magnetic resonance is a promising technology to be applied in many fields. In general, there will be a radial gap in practical application, and some special application environments need to limit the radius of the coils. Therefore, in this paper, considering the comprehensive analysis of the radial gap and the radius of the coils, the concept of the ratio of radial gap to the radius of the coils was proposed. Based on the circuit theory, the formula between the ratio and transmission efficiency of WPT was deduced, and the effects of the ratio on the transmission efficiency were studied respectively at different axial distances. Simulation experiments were carried out and the results not only demonstrate the influence law of the ratio on transmission efficiency, but also validate the value of the ratio which the axial distance has the greatest effect on the transmission efficiency. Besides, the results shows the relationship between the effect of the ratio on the efficiency and the effect of the axial distance on the efficiency. The experimental results show that the theoretical analysis is correct, thus providing an useful theoretical reference for the design and further research on the wireless power transfer system in complicated environment.
Yue, Xiaobin; Xu, Min; Du, Wenhao; Chu, Chong
2017-09-01
Transparent magnesium aluminate spinel (MgAl2O4) ceramic is one of an important optical materials. However, due to its pronounced hardness and brittleness, the optical machining of this material is very difficult. Diamond turning has advantages over the grinding process in flexibility and material removal rate. However, there is a lack of research that could support the use of diamond turning technology in the machining of MgAl2O4 spinel ceramic. Using brittle-ductile transition theory of brittle material machining, this work provides critical information that may help to realize ductile-regime turning of MgAl2O4 spinel ceramic. A characterization method of determination the cutting edge radius is introduced here. Suitable diamond tools were measured for sharpness and then chosen from a large number of candidate tools. The influence of rounded cutting edges on surface roughness of the MgAl2O4 spinel ceramic is also investigated. These results indicate that surface quality of MgAl2O4 spinel is relate to the radius of diamond tool's cutting edge, cutting speed, and feed rate. Sharp diamond tools (small radius of cutting edge) facilitated ductile-regime turning of MgAl2O4 spinel and shows great potential to reduce surface roughness and produce smoother final surface.
Sea quarks contribution to the nucleon magnetic moment and charge radius at the physical point
Sufian, Raza Sabbir; Yang, Yi-Bo; Liang, Jian; Draper, Terrence; Liu, Keh-Fei; χ QCD Collaboration
2017-12-01
We report a comprehensive analysis of the light and strange disconnected-sea quarks contribution to the nucleon magnetic moment, charge radius, and the electric and magnetic form factors. The lattice QCD calculation includes ensembles across several lattice volumes and lattice spacings with one of the ensembles at the physical pion mass. We adopt a model-independent extrapolation of the nucleon magnetic moment and the charge radius. We have performed a simultaneous chiral, infinite volume, and continuum extrapolation in a global fit to calculate results in the continuum limit. We find that the combined light and strange disconnected-sea quarks contribution to the nucleon magnetic moment is μM(DI )=-0.022 (11 )(09 ) μN and to the nucleon mean square charge radius is ⟨r2⟩E(DI ) =-0.019 (05 )(05 ) fm2 which is about 1 /3 of the difference between the ⟨rp2⟩E of electron-proton scattering and that of a muonic atom and so cannot be ignored in obtaining the proton charge radius in the lattice QCD calculation. The most important outcome of this lattice QCD calculation is that while the combined light-sea and strange quarks contribution to the nucleon magnetic moment is small at about 1%, a negative 2.5(9)% contribution to the proton mean square charge radius and a relatively larger positive 16.3(6.1)% contribution to the neutron mean square charge radius come from the sea quarks in the nucleon. For the first time, by performing global fits, we also give predictions of the light and strange disconnected-sea quarks contributions to the nucleon electric and magnetic form factors at the physical point and in the continuum and infinite volume limits in the momentum transfer range of 0 ≤Q2≤0.5 GeV2 .
Reconstruction of lower end of radius using vascularized upper end of fibula
Directory of Open Access Journals (Sweden)
Koul Ashok
2007-01-01
Full Text Available Background: Giant cell tumor is a fairly common locally invasive tumor in young adults. The lower end of the radius is the second commonest site for this tumor. The most common treatment for this tumor is curettage with or without bone grafting but it carries a significant rate of recurrence. Excision is the treatment of choice, especially for cases in which the cortex has been breached. After excision of the distal end of the radius, different procedures have been described to reconstruct the defect of distal radius. These include partial arthrodesis and hemiarthroplasty using the upper end of the fibula. The upper end of the fibula has a morphological resemblance to the lower end of the radius and has been used to replace the latter. Traditionally it was used as a ′free′ (non-vascularized graft. More recently the upper end of the fibula has been transferred as a vascularized transfer for the same purpose. Though vascularized transfer should be expected to be more physiological, its superiority over the technically simpler non-vascularized transfer has not been conclusively proven. Materials and Methods: Two patients are presented who had giant cell tumor of distal radius. They underwent wide local excision and reconstruction with free vascularized upper end of the fibula. Result: Follow-up period was two and a half years and 12 months respectively. Both patients have returned to routine work. One patient has excellent functional result and the other has a good result. Conclusion: Vascularized upper end of fibula transfer is a reliable method of reconstruction for loss of the distal end of the radius that restores local anatomy and physiology.
A Non-Interfering Beam Radius Diagnostic Suitable For Induction Linacs
International Nuclear Information System (INIS)
Nexsen, W E
2005-01-01
High current electron induction linacs operate in a parameter regime that allows the use of a diamagnetic loop (DML) to measure the beam magnetic moment. Under certain easily met conditions the beam radius can be derived from the moment measurement. The DML has the advantage over the present methods of measuring beam radius in that it is an electrical measurement with good time resolution that does not interfere with the beam transport. I describe experiments on the LLNL accelerators, ETA-II and FXR that give confidence in the use of a DML as a beam diagnostic
Yu, Shidi; Liu, Xiao; Liu, Anfeng; Xiong, Naixue; Cai, Zhiping; Wang, Tian
2018-05-10
Due to the Software Defined Network (SDN) technology, Wireless Sensor Networks (WSNs) are getting wider application prospects for sensor nodes that can get new functions after updating program codes. The issue of disseminating program codes to every node in the network with minimum delay and energy consumption have been formulated and investigated in the literature. The minimum-transmission broadcast (MTB) problem, which aims to reduce broadcast redundancy, has been well studied in WSNs where the broadcast radius is assumed to be fixed in the whole network. In this paper, an Adaption Broadcast Radius-based Code Dissemination (ABRCD) scheme is proposed to reduce delay and improve energy efficiency in duty cycle-based WSNs. In the ABCRD scheme, a larger broadcast radius is set in areas with more energy left, generating more optimized performance than previous schemes. Thus: (1) with a larger broadcast radius, program codes can reach the edge of network from the source in fewer hops, decreasing the number of broadcasts and at the same time, delay. (2) As the ABRCD scheme adopts a larger broadcast radius for some nodes, program codes can be transmitted to more nodes in one broadcast transmission, diminishing the number of broadcasts. (3) The larger radius in the ABRCD scheme causes more energy consumption of some transmitting nodes, but radius enlarging is only conducted in areas with an energy surplus, and energy consumption in the hot-spots can be reduced instead due to some nodes transmitting data directly to sink without forwarding by nodes in the original hot-spot, thus energy consumption can almost reach a balance and network lifetime can be prolonged. The proposed ABRCD scheme first assigns a broadcast radius, which doesn’t affect the network lifetime, to nodes having different distance to the code source, then provides an algorithm to construct a broadcast backbone. In the end, a comprehensive performance analysis and simulation result shows that the proposed
DETERMINATION ОF DRESS ROLL OPTIMAL RADIUS WHILE PRODUCING PARTS WITH TROCHOIDAL PROFILE
Directory of Open Access Journals (Sweden)
E. N. Yankevich
2008-01-01
Full Text Available The paper considers determination of the dress roll optimal radius while producing parts having trohoidal profile with the help of grinding method that presupposes application of grinding disk. In this case disk profile has been cut-in by diamond dressing. Two methods for determination of calculation of the dress roll optimal radius have been proposed in the paper. On the basis of the satellite gear of the planetary pin reducer whose profile presents a trochoid it has been shown that the obtained results pertaining to two proposed methods conform with each other.
Tyre effective radius and vehicle velocity estimation: a variable structure observer solution
International Nuclear Information System (INIS)
El Tannoury, C.; Plestan, F.; Moussaoui, S.; ROMANi, N. RENAULT
2011-01-01
This paper proposes an application of a variable structure observer for wheel effective radius and velocity of automotive vehicles. This observer is based on high order sliding approach allowing robustness and finite time convergence. Its originality consists in assuming a nonlinear relation between the slip ratio and the friction coefficient and providing an estimation of both variables, wheel radius and vehicle velocity, from measurement of wheel angular velocity and torque. These signals being available on major modern vehicle CAN (Controller Area Network) buses, this system does not require additional sensors. A simulation example is given to illustrate the relevance of this approach.
Fine-Tuning on the Effective Patch Radius Expression of the Circular Microstrip Patch Antennas
Directory of Open Access Journals (Sweden)
A. E. Yilmaz
2010-09-01
Full Text Available In this study, the effective patch radius expression for the circular microstrip antennas is improved by means of several manipulations. Departing from previously proposed equations in the literature, one of the most accurate equations is picked up, and this equation is fine-tuned by means of Particle Swarm Optimization technique. Throughout the study, impacts of other parameters (such as the definition of the fitness/objective function, the degree-of-freedom in the proposed effective patch radius expression, the number of measured resonant frequency values are observed in a controlled manner. Finally, about 3% additional improvement is achieved over a very accurate formula, which was proposed earlier.
Optimization of the bubble radius in a moving single bubble sonoluminescence
International Nuclear Information System (INIS)
Mirheydari, Mona; Sadighi-Bonabi, Rasoul; Rezaee, Nastaran; Ebrahimi, Homa
2011-01-01
A complete study of the hydrodynamic force on a moving single bubble sonoluminescence in N-methylformamide is presented in this work. All forces exerted, trajectory, interior temperature and gas pressure are discussed. The maximum values of the calculated components of the hydrodynamic force for three different radii at the same driving pressure were compared, while the optimum bubble radius was determined. The maximum value of the buoyancy force appears at the start of bubble collapse, earlier than the other forces whose maximum values appear at the moment of bubble collapse. We verified that for radii larger than the optimum radius, the temperature peak value decreases.
On the ππ continuum in the nucleon form factors and the proton radius puzzle
Hoferichter, M.; Kubis, B.; Ruiz de Elvira, J.; Hammer, H.-W.; Meißner, U.-G.
2016-11-01
We present an improved determination of the ππ continuum contribution to the isovector spectral functions of the nucleon electromagnetic form factors. Our analysis includes the most up-to-date results for the ππ→bar{N} N partial waves extracted from Roy-Steiner equations, consistent input for the pion vector form factor, and a thorough discussion of isospin-violating effects and uncertainty estimates. As an application, we consider the ππ contribution to the isovector electric and magnetic radii by means of sum rules, which, in combination with the accurately known neutron electric radius, are found to slightly prefer a small proton charge radius.
On the ππ continuum in the nucleon form factors and the proton radius puzzle
International Nuclear Information System (INIS)
Hoferichter, M.; Kubis, B.; Ruiz de Elvira, J.; Hammer, H.W.; Meissner, U.G.
2016-01-01
We present an improved determination of the ππ continuum contribution to the isovector spectral functions of the nucleon electromagnetic form factors. Our analysis includes the most up-to-date results for the ππ → anti NN partial waves extracted from Roy-Steiner equations, consistent input for the pion vector form factor, and a thorough discussion of isospin-violating effects and uncertainty estimates. As an application, we consider the ππ contribution to the isovector electric and magnetic radii by means of sum rules, which, in combination with the accurately known neutron electric radius, are found to slightly prefer a small proton charge radius. (orig.)
Measuring Atmospheric Abundances and Rotation of a Brown Dwarf with a Measured Mass and Radius
Birkby, Jayne
2015-08-01
There are no cool brown dwarfs with both a well-characterized atmosphere and a measured mass and radius. LHS 6343, a brown dwarf transiting one member of an M+M binary in the Kepler field, provides the first opportunity to tie theoretical atmospheric models to the observed brown dwarf mass-radius diagram. We propose four half-nights of observations with NIRSPAO in 2015B to measure spectral features in LHS 6343 C by detecting the relative motions of absorption features during the system's orbit. In addition to abundances, we will directly measure the brown dwarf's projected rotational velocity and mass.
On the ππ continuum in the nucleon form factors and the proton radius puzzle
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, M. [University of Washington, Institute for Nuclear Theory, Seattle, WA (United States); Kubis, B.; Ruiz de Elvira, J. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany); Hammer, H.W. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, ExtreMe Matter Institute EMMI, Darmstadt (Germany); Meissner, U.G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Bonn (Germany); Institut fuer Kernphysik, Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, Juelich (Germany)
2016-11-15
We present an improved determination of the ππ continuum contribution to the isovector spectral functions of the nucleon electromagnetic form factors. Our analysis includes the most up-to-date results for the ππ → anti NN partial waves extracted from Roy-Steiner equations, consistent input for the pion vector form factor, and a thorough discussion of isospin-violating effects and uncertainty estimates. As an application, we consider the ππ contribution to the isovector electric and magnetic radii by means of sum rules, which, in combination with the accurately known neutron electric radius, are found to slightly prefer a small proton charge radius. (orig.)
An Adaption Broadcast Radius-Based Code Dissemination Scheme for Low Energy Wireless Sensor Networks
Directory of Open Access Journals (Sweden)
Shidi Yu
2018-05-01
Full Text Available Due to the Software Defined Network (SDN technology, Wireless Sensor Networks (WSNs are getting wider application prospects for sensor nodes that can get new functions after updating program codes. The issue of disseminating program codes to every node in the network with minimum delay and energy consumption have been formulated and investigated in the literature. The minimum-transmission broadcast (MTB problem, which aims to reduce broadcast redundancy, has been well studied in WSNs where the broadcast radius is assumed to be fixed in the whole network. In this paper, an Adaption Broadcast Radius-based Code Dissemination (ABRCD scheme is proposed to reduce delay and improve energy efficiency in duty cycle-based WSNs. In the ABCRD scheme, a larger broadcast radius is set in areas with more energy left, generating more optimized performance than previous schemes. Thus: (1 with a larger broadcast radius, program codes can reach the edge of network from the source in fewer hops, decreasing the number of broadcasts and at the same time, delay. (2 As the ABRCD scheme adopts a larger broadcast radius for some nodes, program codes can be transmitted to more nodes in one broadcast transmission, diminishing the number of broadcasts. (3 The larger radius in the ABRCD scheme causes more energy consumption of some transmitting nodes, but radius enlarging is only conducted in areas with an energy surplus, and energy consumption in the hot-spots can be reduced instead due to some nodes transmitting data directly to sink without forwarding by nodes in the original hot-spot, thus energy consumption can almost reach a balance and network lifetime can be prolonged. The proposed ABRCD scheme first assigns a broadcast radius, which doesn’t affect the network lifetime, to nodes having different distance to the code source, then provides an algorithm to construct a broadcast backbone. In the end, a comprehensive performance analysis and simulation result shows that
Collision free path generation in 3D with turning and pitch radius constraints for aerial vehicles
DEFF Research Database (Denmark)
Schøler, F.; La Cour-Harbo, A.; Bisgaard, M.
2009-01-01
In this paper we consider the problem of trajectory generation in 3D for uninhabited aerial systems (UAS). The proposed algorithm for trajectory generation allows us to find a feasible collision-free 3D trajectory through a number of waypoints in an environment containing obstacles. Our approach...... assumes that most of the aircraft structural and dynamic limitations can be formulated as a turn radius constraint, and that any two consecutive waypoints have line-of-sight. The generated trajectories are collision free and also satisfy a constraint on the minimum admissible turning radius, while...
An estimation of the spatial coherency radius of a multimode laser beam by the spectral contrast
Energy Technology Data Exchange (ETDEWEB)
Sukhanov, I I
1983-01-01
The angular dependency of the spectral contrast behind a diffuser illuminated by an He/Ne laser beam at .63 micrometers on the number of transverse modes is investigated. It is demonstrated that over a wide range of scattering angles, the contrast is determined primarily by the number of transverse modes, i.e. by the radius of the spatial field correlation, and is only slightly dependent on the dimensions and shape of the beam as well as the intensity distribution in the beam. These results may be useful in developing a rapid indication method of the radius of the spatial correlation of laser beams.
Testing the white dwarf mass-radius relationship with eclipsing binaries
Parsons, S. G.; Gänsicke, B. T.; Marsh, T. R.; Ashley, R. P.; Bours, M. C. P.; Breedt, E.; Burleigh, M. R.; Copperwheat, C. M.; Dhillon, V. S.; Green, M.; Hardy, L. K.; Hermes, J. J.; Irawati, P.; Kerry, P.; Littlefair, S. P.; McAllister, M. J.; Rattanasoon, S.; Rebassa-Mansergas, A.; Sahman, D. I.; Schreiber, M. R.
2017-10-01
We present high-precision, model-independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries and combine these with previously published data to test the theoretical white dwarf mass-radius relationship. We reach a mean precision of 2.4 per cent in mass and 2.7 per cent in radius, with our best measurements reaching a precision of 0.3 per cent in mass and 0.5 per cent in radius. We find excellent agreement between the measured and predicted radii across a wide range of masses and temperatures. We also find the radii of all white dwarfs with masses less than 0.48 M⊙ to be fully consistent with helium core models, but they are on average 9 per cent larger than those of carbon-oxygen core models. In contrast, white dwarfs with masses larger than 0.52 M⊙ all have radii consistent with carbon-oxygen core models. Moreover, we find that all but one of the white dwarfs in our sample have radii consistent with possessing thick surface hydrogen envelopes (10-5 ≥ MH/MWD ≥ 10-4), implying that the surface hydrogen layers of these white dwarfs are not obviously affected by common envelope evolution.
Determination of the radius of a self-pinched beam from its energy integral
International Nuclear Information System (INIS)
Lee, E.P.
1980-01-01
The total transverse energy (kinetic plus potential) of a self-pinched beam may be used to predict the final equilibrium radius when the beam is mismatched at injection. The dependence of potential energy on the current profile shape is characterized by a dimensionless parameter C(z), variations of which are correlated with the change of emittance
Perimeter generating functions for the mean-squared radius of gyration of convex polygons
International Nuclear Information System (INIS)
Jensen, Iwan
2005-01-01
We have derived long series expansions for the perimeter generating functions of the radius of gyration of various polygons with a convexity constraint. Using the series we numerically find simple (algebraic) exact solutions for the generating functions. In all cases the size exponent ν 1. (letter to the editor)
Turnaround radius in an accelerated universe with quasi-local mass
Energy Technology Data Exchange (ETDEWEB)
Faraoni, Valerio; Lapierre-Léonard, Marianne; Prain, Angus, E-mail: vfaraoni@ubishops.ca, E-mail: mlapierre12@ubishops.ca, E-mail: angusprain@gmail.com [Physics Department, Bishop' s University, 2600 College Street, Sherbrooke, Québec, J1M 1Z7 Canada (Canada)
2015-10-01
We apply the Hawking-Hayward quasi-local energy construct to obtain in a rigorous way the turnaround radius of cosmic structures in General Relativity. A splitting of this quasi-local mass into local and cosmological parts describes the interplay between local attraction and cosmological expansion.
Turnaround radius in an accelerated universe with quasi-local mass
International Nuclear Information System (INIS)
Faraoni, Valerio; Lapierre-Léonard, Marianne; Prain, Angus
2015-01-01
We apply the Hawking-Hayward quasi-local energy construct to obtain in a rigorous way the turnaround radius of cosmic structures in General Relativity. A splitting of this quasi-local mass into local and cosmological parts describes the interplay between local attraction and cosmological expansion
Determination of bone mineral density at distal radius measured by single photon absorptiometry
International Nuclear Information System (INIS)
Tomomitsu, Tatsushi; Yanagimoto, Shinichi; Hitomi, Go; Murakami, Akihiko; Suemori, Shinji; Yokobayashi, Tsuneo; Ishii, Koshi; Hiji, Hiroo
1988-01-01
We have discussed the index of the bone mineral density (BMD) at the distal radius measured by single photon absorptiometry. Initially, the shape at the distal radius was evaluated using an X-ray photogram of the forearm and a calculation formula of the cross-sectional area at the distal radius was performed using an X-CT photogram of the forearm. A new index for the bone mineral density (modified BMD, mBMD), bone mineral content/cross-sectional area, at the distal radius was obtained for 154 young normal subjects (20 ∼ 44 yrs.). No significant differences in the mBMD values between young normal males and females, except for the group 20 ∼ 24 year-old group, were observed. Furthermore, a significantly decreased in the mBMD values with aging was observed in females between the ages of 20 ∼ 24 and 40 ∼ 44. However, no significant changes in the mBMD values were recognized in the men. Thus, it was shown that the new BMD index, mBMD, was useful for evaluating the changes of the bone mass. (author)
Sex determination from the radius and ulna in a modern South African sample.
Barrier, I L O; L'Abbé, E N
2008-07-18
With a large number of unidentified skeletal remains found in South Africa, the development of population specific osteometric standards is imperative. Forensic anthropologists need to have access to a variety of techniques to establish accurate demographic profiles from complete, fragmentary and/or commingled remains. No research has been done on the forearm of African samples, even though these bones have been shown to exhibit sexual dimorphism. The purpose of this paper is to develop discriminant function formulae to determine sex from the radius and ulna in a South African population. The sample consisted of 200 male and 200 female skeletons from the Pretoria Bone (University of Pretoria) and Raymond A. Dart (Witwatersrand University) collections. Sixteen standard anthropometric measurements were taken from the radius (9) and ulna (7) and subjected to stepwise and direct discriminant function analysis. Distal breadth, minimum mid-shaft diameter and maximum head diameter were the best discriminators of sex for the radius, while minimum mid-shaft diameter and olecranon breadth were selected for the ulna. Classification accuracy for the forearm ranged from 76 to 86%. The radius and ulna can be considered moderate discriminators for determining sex in a South African group. However, it is advised that these formulae are used in conjunction with additional methods to determine sex.
Constraining the mass and radius of neutron stars in globular clusters
Steiner, A. W.; Heinke, C. O.; Bogdanov, S.; Li, C. K.; Ho, W. C. G.; Bahramian, A.; Han, S.
2018-05-01
We analyse observations of eight quiescent low-mass X-ray binaries in globular clusters and combine them to determine the neutron star mass-radius curve and the equation of state of dense matter. We determine the effect that several uncertainties may have on our results, including uncertainties in the distance, the atmosphere composition, the neutron star maximum mass, the neutron star mass distribution, the possible presence of a hotspot on the neutron star surface, and the prior choice for the equation of state of dense matter. The distance uncertainty is implemented in a new Gaussian blurring method that can be directly applied to the probability distribution over mass and radius. We find that the radius of a 1.4 solar mass neutron star is most likely from 10 to 14 km and that tighter constraints are only possible with stronger assumptions about the nature of the neutron stars, the systematics of the observations, or the nature of dense matter. Strong phase transitions in the equation of state are preferred, and in this case, the radius is likely smaller than 12 km. However, radii larger than 12 km are preferred if the neutron stars have uneven temperature distributions.
Influence of radius of cylinder HTS bulk on guidance force in a maglev vehicle system
Longcai, Zhang
2014-07-01
Bulk superconductors had great potential for various engineering applications, especially in a high-temperature superconducting (HTS) maglev vehicle system. In such a system, the HTS bulks were always exposed to AC external magnetic field, which was generated by the inhomogeneous surface magnetic field of the NdFeB guideway. In our previous work, it was observed that the guidance force of the YBCO bulk over the NdFeB guideway used in the HTS maglev vehicle system was decayed by the application of the AC external magnetic field. In this paper, we investigated the influence of the radius of the cylinder HTS bulk exposed to an AC magnetic field perturbation on the guidance force in the maglev vehicle system. From the results, it was found that the guidance force was stronger for the bulk with bigger radius and the guidance force decay rates of the bulks were approximately equal despite of the different radius in the maglev vehicle system. Therefore, in order to obtain higher guidance force in the maglev vehicle system, we could use the cylinder HTS bulks with the bigger radius.
International Nuclear Information System (INIS)
Li Bingan
1988-01-01
In this letter it is shown that even in m π ≠ 0 case the Goldberger-Treiman relation is still hold in the Skyrme model. The mean square radius of strong interaction of nucleon 2 > s 1/2 is computed in the Skyrme model
A Spitzer Infrared Radius for the Transiting Extrasolar Planet HD 209458 b
Richardson, L. Jeremy; Harrington, Joseph; Seager, Sara; Deming, Drake
2007-01-01
We have measured the infrared transit of the extrasolar planet HD 209458 b using the Spitzer Space Telescope. We observed two primary eclipse events (one partial and one complete transit) using the 24 micrometer array of the Multiband Imaging Photometer for Spitzer (MIPS). We analyzed a total of 2392 individual images (10-second integrations) of the planetary system, recorded before, during, and after transit. We perform optimal photometry on the images and use the local zodiacal light as a short-term flux reference. At this long wavelength, the transit curve has a simple box-like shape, allowing robust solutions for the stellar and planetary radii independent of stellar limb darkening, which is negligible at 24 micrometers. We derive a stellar radius of R(sub *) = 1.06 plus or minus 0.07 solar radius, a planetary radius of R(sub p) = 1.26 plus or minus 0.08 R(sub J), and a stellar mass of 1.17 solar mass. Within the errors, our results agree with the measurements at visible wavelengths. The 24 micrometer radius of the planet therefore does not differ significantly compared to the visible result. We point out the potential for deriving extrasolar transiting planet radii to high accuracy using transit photometry at slightly shorter IR wavelengths where greater photometric precision is possible.
Peak incidence of distal radius fractures due to ice skating on natural ice in The Netherlands
van Lieshout, Arno P. W.; van Manen, Christiaan J.; du Pré, Karel J.; Kleinlugtenbelt, Ydo V.; Poolman, Rudolf W.; Goslings, J. Carel; Kloen, Peter
2010-01-01
An increase of distal radius fractures was seen in 2009 when an extended cold spell allowed natural ice skating in Amsterdam. This resulted in overload of our Emergency Departments and operating rooms. This study reports patient and fracture characteristics of these injuries. We also determined
Two peg spade plate for distal radius fractures A novel technique
Directory of Open Access Journals (Sweden)
Sharad M Hardikar
2015-01-01
Conclusions: The two peg volar spade plate provides a stable subchondral support in comminuted intraarticular fractures and maintains reduction in osteoporotic fractures of the distal radius. Early mobilization with this implant helps in restoring wrist motion and to prevent development of wrist stiffness.
Stello, Dennis; Chaplin, William J.; Bruntt, Hans; Creevey, Orlagh L.; García-Hernández, Antonio; Monteiro, Mario J. P. F. G.; Moya, Andrés; Quirion, Pierre-Olivier; Sousa, Sergio G.; Suárez, Juan-Carlos; Appourchaux, Thierry; Arentoft, Torben; Ballot, Jerome; Bedding, Timothy R.; Christensen-Dalsgaard, Jørgen; Elsworth, Yvonne; Fletcher, Stephen T.; García, Rafael A.; Houdek, Günter; Jiménez-Reyes, Sebastian J.; Kjeldsen, Hans; New, Roger; Régulo, Clara; Salabert, David; Toutain, Thierry
2009-08-01
For distant stars, as observed by the NASA Kepler satellite, parallax information is currently of fairly low quality and is not complete. This limits the precision with which the absolute sizes of the stars and their potential transiting planets can be determined by traditional methods. Asteroseismology will be used to aid the radius determination of stars observed during NASA's Kepler mission. We report on the recent asteroFLAG hare-and-hounds Exercise#2, where a group of "hares" simulated data of F-K main-sequence stars that a group of "hounds" sought to analyze, aimed at determining the stellar radii. We investigated stars in the range 9 values of the artificial stars to within 3%, when the large frequency spacing is used. This is 5-10 times better than the results where seismology is not applied. These results give strong confidence that radius estimation can be performed to better than 3% for solar-like stars using automatic pipeline reduction. Even when the stellar distance and luminosity are unknown we can obtain the same level of agreement. Given the uncertainties used for this exercise we find that the input log g and parallax do not help to constrain the radius, and that T eff and metallicity are the only parameters we need in addition to the large frequency spacing. It is the uncertainty in the metallicity that dominates the uncertainty in the radius.
Orientation illusions and heart-rate changes during short-radius centrifugation
Hecht, H.; Kavelaars, J.; Cheung, C. C.; Young, L. R.
2001-01-01
Intermittent short-radius centrifugation is a promising countermeasure against the adverse effects of prolonged weightlessness. To assess the feasibility of this countermeasure, we need to understand the disturbing sensory effects that accompany some movements carried out during rotation. We tested
Kinematics and early migration in single-radius mobile- and fixed-bearing total knee prostheses
Wolterbeek, N.; Garling, E.H.; Mertens, B.J.; Nelissen, R.G.H.H.; Valstar, E.R.
2012-01-01
Background The mobile-bearing variant of a single-radius design is assumed to provide more freedom of motion compared to the fixed-bearing variant because the insert does not restrict the natural movements of the femoral component. This would reduce the contact stresses and wear which in turn may
Pole-strength of the earth from Magsat and magnetic determination of the core radius
Voorhies, G. V.; Benton, E. R.
1982-01-01
A model based on two days of Magsat data is used to numerically evaluate the unsigned magnetic flux linking the earth's surface, and a comparison of the 16.054 GWb value calculated with values from earlier geomagnetic field models reveals a smooth, monotonic, and recently-accelerating decrease in the earth's pole strength at a 50-year average rate of 8.3 MWb, or 0.052%/year. Hide's (1978) magnetic technique for determining the radius of the earth's electrically-conducting core is tested by (1) extrapolating main field models for 1960 and 1965 downward through the nearly-insulating mantle, and then separately comparing them to equivalent, extrapolated models of Magsat data. The two unsigned fluxes are found to equal the Magsat values at a radius which is within 2% of the core radius; and (2) the 1960 main field and secular variation and acceleration coefficients are used to derive models of 1930, 1940 and 1950. The same core magnetic radius value, within 2% of the seismic value, is obtained. It is concluded that the mantle is a nearly-perfect insulator, while the core is a perfect conductor, on the decade time scale.
The ephemeris and variations of the accretion disc radius in IP Pegasi
International Nuclear Information System (INIS)
Wood, J.H.; Robinson, E.L.
1989-01-01
We present timings of 37 previously unpublished eclipses of the dwarf nova IP Pegasi, obtained in 1986 through to 1988, and combine these with earlier published timings in order to update the orbital ephemeris and to examine the behaviour of the accretion disc radius through the outburst cycle. (author)
International Nuclear Information System (INIS)
Rezende, C.M.F.; Melo, E.G.; Lamas, M.C.S.; Silva, C.A.
2000-01-01
The clinical exam of a male mongrel dog, 4-month-old, and 5.7kg of live weight, showed that the dog supported with the elbows and it was observed accentuated bilateral rotacional deformity of the radius and ulna. Radiographs of the radius and ulna revealed proximal fracture of the radius. After clinical and radiographic evaluation it was indicated the corrective osteotomy and distraction osteogenesis of the left foremember. The surgical procedure consisted in osteotomy in the diaphysis of the radius and ulna, and the utilization of external fixators composed by four Kirschner’s pins and two metallic thread bars, configuring a fixator type II, bilateral uniplanar dynamic. Before the fixation of the pins with acrylic, the fractured bony fragments were separated in approximately 0.5cm. Starting 10 days post surgery, the radial osteotomy site was distracted at a rate of 1.0mm every day for 30 days. The consolidation of the osteotomy site was observed radiographically 67 days after the intervention, when the fixator was removed. Similar procedure was accomplished in the right foremember at the age of 16 months. At this moment, it was necessary to remove a coins bony of approximately 1.0cm for correction of the limb angulation. At present, the dog shows normal function and support of the left foremember and light valgus deformity of the right foremember due to the broken implants [pt
Mercury's radius change estimates revisited using high incidence angle MESSENGER data
Di Achille, G.; Popa, C.; Massironi, M.; Ferrari, S.; Mazzotta Epifani, E.; Zusi, M.; Cremonese, G.; Palumbo, P.
2012-04-01
Estimates of Mercury's radius decrease obtained using the amount of strain recorded by tectonics on the planet range from 0.5 km to 2 km. These latter figures appear too low with respect to the radius contraction (up to 5-6 km) predicted by the most accredited studies based on thermo-mechanical evolution models. For this reason, it has been suggested that there may be hidden strain accommodated by features yet unseen on Mercury. Indeed, as it has been already cautioned by previous studies, the identification of tectonic features on Mercury might be largely biased by the lighting geometry of the used basemaps. This limitation might have affected the results of the extrapolations for estimating the radius change. In this study, we mapped tectonic features at the terminator thus using images acquired at high sun incidence angle (>50°) that represents the optimal condition for their observation. In fact, images with long shadows enhance the topography and texture of the surface and are ideal to detect tectonic structures. This favorable illumination conditions allowed us to infer reliable measurements of spatial distribution (i.e. frequency, orientation, and areal density) of tectonic features which can be used to estimate the average contractional strain and planetary radius decrease. We digitized tectonic structures within a region extending for an area of about 12 million sq. km (~16% of planet's surface). More than 1300 tectonic lineaments were identified and interpreted to be compressional features (i.e. lobate scarps, wrinkle ridges, and high relief ridges) with a total length of more than 12300 km. Assuming that the extensional strain is negligible within the area, the average contractional strain calculated for the survey area is ~0.21-0.28% (~0.24% for θ=30°). This strain, extrapolated to the entire surface, corresponds to a contraction in radius of about 2.5-3.4 km (~2.9 km for θ=30°). Interestingly, the values of contractional strain and radius decrease
A method for determining the radius of an open cluster from stellar proper motions
Sánchez, Néstor; Alfaro, Emilio J.; López-Martínez, Fátima
2018-04-01
We propose a method for calculating the radius of an open cluster in an objective way from an astrometric catalogue containing, at least, positions and proper motions. It uses the minimum spanning tree in the proper motion space to discriminate cluster stars from field stars and it quantifies the strength of the cluster-field separation by means of a statistical parameter defined for the first time in this paper. This is done for a range of different sampling radii from where the cluster radius is obtained as the size at which the best cluster-field separation is achieved. The novelty of this strategy is that the cluster radius is obtained independently of how its stars are spatially distributed. We test the reliability and robustness of the method with both simulated and real data from a well-studied open cluster (NGC 188), and apply it to UCAC4 data for five other open clusters with different catalogued radius values. NGC 188, NGC 1647, NGC 6603, and Ruprecht 155 yielded unambiguous radius values of 15.2 ± 1.8, 29.4 ± 3.4, 4.2 ± 1.7, and 7.0 ± 0.3 arcmin, respectively. ASCC 19 and Collinder 471 showed more than one possible solution, but it is not possible to know whether this is due to the involved uncertainties or due to the presence of complex patterns in their proper motion distributions, something that could be inherent to the physical object or due to the way in which the catalogue was sampled.
Wichlas, Florian; Tsitsilonis, Serafim; Kopf, Sebastian; Krapohl, Björn Dirk; Manegold, Sebastian
2017-01-01
Introduction: The aim of the present study is to develop a heuristic that could replace the surgeon's analysis for the decision on the operative approach of distal radius fractures based on simple fracture characteristics. Patients and methods: Five hundred distal radius fractures operated between 2011 and 2014 were analyzed for the surgeon's decision on the approach used. The 500 distal radius fractures were treated with open reduction and internal fixation through palmar, dorsal, and dorsopalmar approaches with 2.4 mm locking plates or underwent percutaneous fixation. The parameters that should replace the surgeon's analysis were the fractured palmar cortex, and the frontal and the sagittal split of the articular surface of the distal radius. Results: The palmar approach was used for 422 (84.4%) fractures, the dorsal approach for 39 (7.8%), and the combined dorsopalmar approach for 30 (6.0%). Nine (1.8%) fractures were treated percutaneously. The correlation between the fractured palmar cortex and the used palmar approach was moderate (r=0.464; p<0.0001). The correlation between the frontal split and the dorsal approach, including the dorsopalmar approach, was strong (r=0.715; p<0.0001). The sagittal split had only a weak correlation for the dorsal and dorsopalmar approach (r=0.300; p<0.0001). Discussion: The study shows that the surgical decision on the preferred approach is dictated through two simple factors, even in the case of complex fractures. Conclusion: When the palmar cortex is displaced in distal radius fractures, a palmar approach should be used. When there is a displaced frontal split of the articular surface, a dorsal approach should be used. When both are present, a dorsopalmar approach should be used. These two simple parameters could replace the surgeon's analysis for the surgical approach.
The Assessment of Left Ventricular Time-Varying Radius Using Tissue Doppler Imaging
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Fardin Mirbolouk
2012-03-01
Full Text Available Background: Left ventricular twist/torsion is believed to be a sensitive indicator of systolic and diastolic performance. To obtain circumferential rotation using tissue Doppler imaging, we need to estimate the time-varying radius of the left ventricle throughout the cardiac cycle to convert the tangential velocity into angular velocity. Objectives: The aim of this study was to investigate accuracy of measured LV radius using tissue Doppler imaging throughout the cardiac cycle compared to two-dimensional (2D imaging. Methods: A total of 35 subjects (47±12 years old underwent transthoracic echocardiographic standard examinations. Left ventricular radius during complete cardiac cycle measured using tissue Doppler and 2D-imaging at basal and apical short axis levels. For this reason, the 2D-images and velocity-time data derived and transferred to a personal computer for off-line analysis. 2D image frames analyzed via a program written in the MATLAB software. Velocity-time data from anteroseptal at basal level (or anterior wall at apical level and posterior walls transferred to a spreadsheet Excel program for the radius calculations. Linear correlation and Bland-Altman analysis were calculated to assess the relationships and agreements between the tissue Doppler and 2D-measured radii throughout the cardiac cycle. Results: There was significant correlation between tissue Doppler and 2D-measured radii and the Pearson correlation coefficients were 0.84 to 0.97 (P<0.05. Bland-Altman analysis by constructing the 95% limits of agreement showed that the good agreements existed between the two methods. Conclusion: It can be concluded from our experience that the tissue Doppler imaging can reasonably estimate radius of the left ventricle throughout the cardiac cycle.
MRI of fractures of the distal radius: comparison with conventional radiographs
International Nuclear Information System (INIS)
Spence, L.D.; Eustace, S.
1998-01-01
Objective. To compare the evaluation of fractures of the distal radius with MRI and conventional radiographs. To demonstrate the ability of MRI to detect unsuspected soft tissue derangement accompanying this common injury. Design and patients. Twenty-one consecutive inpatients admitted following fracture of the distal radius underwent preoperative evaluation with both conventional radiographs and MRI. In each case, analysis was made of both the osseous and soft tissue injury. MRI findings were compared with those identified on conventional radiographs and at subsequent surgical fixation. Results. Of 21 patients with fractures of the distal radius, 20 had extension to the radiocarpal articulation, 14 had distal radio-ulnar joint extension and 5 had avulsion of the ulnar styloid.Occult carpal bone fractures accompanying fracture of the distal radius were identified in two patients: one of the capitate and the other of the second metacarpal base. Ten patients (48%) had associated soft tissue injury: six patients had scapholunate ligament rupture, two patients had disruption of the triangular fibrocartilage, one patient had extensor carpi ulnaris tenosynovitis and one patient had a tear of a dorsal radiocarpal ligament. Of five patients with ulnar styloid avulsions, none had evidence of triangular fibrocartilage tears. Conclusion. MRI affords better evaluation of osseous injury accompanying distal radial fractures than conventional radiographs. Intra-articular soft tissue injury accompanies distal radial fractures in almost 50% of cases. Scapholunate ligament disruption commonly accompanies intra-articular fracture through the lunate facet of the distal radius. Fracture of the ulnar styloid is infrequently associated with tear of the triangular fibrocartilage. (orig.)
[Distal radius fractures--retrospective quality control after conservative and operative therapy].
Sommer, C; Brendebach, L; Meier, R; Leutenegger, A
2001-01-01
The distal radius fracture is the most frequent fracture in the adult patient. The wide spectrum of different types of fracture and the coexisting factors make the choice for the optimal treatment difficult. As an interne quality control we retrospectively evaluated all patients with distal radius fractures treated in 1995 at our institution. The study included 69 adult patients with 71 distal radius fractures. After on average 26 months 58 patients with 59 fractures were clinically and radiologically evaluated. The patients were asked to give supplementary information about their follow-up treatment as well as any remaining physical difficulties and limitations in the daily life. All x-rays of the broken radius were carefully analysed and compared with the opposite side. The final results were evaluated according to the "Demerit Point System". Patients were treated with five different therapeutical methods. 76.3% of the patients showed a very good/good final result. In 56.7% of the cases secondary fracture dislocation occurred; the dislocation-rate of fractures treated with percutaneous k-wires was 93.3%! A clear correlation between secondary displacement and final results was found. A main factor for an optimal outcome is the anatomic restoration of length and axis of the distal radius as well as of joint congruency, also moderate angular deformities are well tolerated. Our collective showed an unexpected high rate of secondary displacement, especially in the k-wire group. The reasons for this unsatisfactory event are manifold: too optimistic indication, insufficient follow-up examination in the first four to six weeks, inconsequent change to a more stable fixation method in case of a secondary dislocation. The results of this retrospective evaluation had a major impact on our concept of treatment. The dorso-radial double-plate technique combined with bone graft will be more used in the future especially in younger patients. The new standardised concept is the
MRI of fractures of the distal radius: comparison with conventional radiographs
Energy Technology Data Exchange (ETDEWEB)
Spence, L.D.; Eustace, S. [Medical Center, Boston, MA (United States). Dept. of Radiol.; Savenor, A.; Nwachuku, I.; Tilsley, J. [Department of Orthopedics, Boston Medical Center, Boston, MA 02118 (United States)
1998-05-01
Objective. To compare the evaluation of fractures of the distal radius with MRI and conventional radiographs. To demonstrate the ability of MRI to detect unsuspected soft tissue derangement accompanying this common injury. Design and patients. Twenty-one consecutive inpatients admitted following fracture of the distal radius underwent preoperative evaluation with both conventional radiographs and MRI. In each case, analysis was made of both the osseous and soft tissue injury. MRI findings were compared with those identified on conventional radiographs and at subsequent surgical fixation. Results. Of 21 patients with fractures of the distal radius, 20 had extension to the radiocarpal articulation, 14 had distal radio-ulnar joint extension and 5 had avulsion of the ulnar styloid.Occult carpal bone fractures accompanying fracture of the distal radius were identified in two patients: one of the capitate and the other of the second metacarpal base. Ten patients (48%) had associated soft tissue injury: six patients had scapholunate ligament rupture, two patients had disruption of the triangular fibrocartilage, one patient had extensor carpi ulnaris tenosynovitis and one patient had a tear of a dorsal radiocarpal ligament. Of five patients with ulnar styloid avulsions, none had evidence of triangular fibrocartilage tears. Conclusion. MRI affords better evaluation of osseous injury accompanying distal radial fractures than conventional radiographs. Intra-articular soft tissue injury accompanies distal radial fractures in almost 50% of cases. Scapholunate ligament disruption commonly accompanies intra-articular fracture through the lunate facet of the distal radius. Fracture of the ulnar styloid is infrequently associated with tear of the triangular fibrocartilage. (orig.) With 5 figs., 16 refs.
Directory of Open Access Journals (Sweden)
L. A. Gubanova
2015-03-01
Full Text Available The paper deals with findings for the energy reflection coefficient distribution of anti- reflection coating along the surface of optical elements with a very small radius (2-12 mm. The factors influencing the magnitude of the surface area of the optical element, in which the energy reflection coefficient is constant, were detected. The main principles for theoretical models that describe the spectral characteristics of the multilayer interference coatings were used to achieve these objectives. The relative size of the enlightenment area is defined as the ratio of the radius for the optical element surface, where the reflection is less than a certain value, to its radius (ρ/r. The result of research is the following: this size is constant for a different value of the curvature radius for the optical element made of the same material. Its value is determined by the refractive index of material (nm, from which the optical element was made, and the design of antireflection coatings. For single-layer coatings this value is ρ/r = 0.5 when nm = 1.51; and ρ/r = 0.73 when nm = 1.75; for two-layer coatings ρ/r = 0.35 when nm = 1.51 and ρ/r = 0.41 when nm = 1.75. It is shown that with increasing of the material refractive index for the substrate size, the area of minimum reflection coefficient is increased. The paper considers a single-layer, two-layer, three-layer and five-layer structures of antireflection coatings. The findings give the possibility to conclude that equal thickness coverings formed on the optical element surface with a small radius make no equal reflection from the entire surface, and distribution of the layer thickness needs to be looked for, providing a uniform radiation reflection at all points of the spherical surface.
The QCD model of hadron cores of the meson theory
International Nuclear Information System (INIS)
Pokrovskii, Y.E.
1985-01-01
It was shown that in the previously proposed QCD model of hadron cores the exchange and self-energy contributions of the virtual quark-antiquark-gluon cloud on the outside of a bag which radius coincides with the hardon core radius of the meson theory (∼ 0.4 Fm) have been taken into account at the phenomenological level. Simulation of this cloud by the meson field results in realistic estimations of the nucleon's electroweak properties, moment fractions carried by gluons, quarks, antiquarks and hadron-hadron interaction cross-sections within a wide range of energies. The authors note that the QCD hadron core model proposed earlier not only realistically reflects the hadron masses, but reflects self-consistently main elements of the structure and interaction of hadrons at the quark-gluon bag radius (R - 0.4Fm) being close to the meson theory core radius
Energy Technology Data Exchange (ETDEWEB)
Li, Zhaosheng [Department of Physics, Xiangtan University, Xiangtan, 411105 (China); Falanga, Maurizio [International Space Science Institute, Hallerstrasse 6, 3012 Bern (Switzerland); Chen, Li [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Qu, Jinlu [Laboratory for Particle Astrophysics, Institute of High Energy Physics, CAS, Beijing 100049 (China); Xu, Renxin, E-mail: lizhaosheng@xtu.edu.cn [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)
2017-08-10
The measurement of neutron star mass and radius is one of the most direct ways to distinguish between various dense matter equations of state. The mass and radius of accreting neutron stars hosted in low-mass X-ray binaries can be constrained by several methods, including photospheric radius expansion from type I X-ray bursts and from quiescent spectra. In this paper, we apply for the first time these two methods simultaneously to constrain the mass and radius of Aql X–1. The quiescent spectra from Chandra and XMM-Newton , and photospheric radius expansion bursts from RXTE are used. The determination of the mass and radius of Aql X–1 is also used to verify the consistency between the two methods and to narrow down the uncertainties of the neutron star mass and radius. It is found that the distance to Aql X–1 should be in the range of 4.0–5.75 kpc, based on the overlapping confidence regions between photospheric radius expansion burst and quiescent spectra methods. In addition, we show that the mass and radius determined for the compact star in Aql X–1 are compatible with strange star equations of state and conventional neutron star models.
Analysis of the radius and diameter protocols in terms of pricing telecommunication services
Directory of Open Access Journals (Sweden)
Vesna M. Radonjić
2013-06-01
Full Text Available Accounting of telecommunication services is closely related to the functions of authentication and authorization. These functions are usually considered together and implemented within the same server using a common protocol. The most renowned protocols for authentication, authorization and accounting are the RADIUS and Diameter protocols. AAA functions and related protocols In this chapter, the accounting management architecture developed by IETF is presented. It includes the interaction between network elements, accounting servers and billing and charging servers. Accounting data can be used for management, planning and charging users as well as other (specific purposes. Authentication is the process of confirming a user's digital identity, usually through some type of identifiers and related data. Authorization determines whether a particular entity is authorized to perform an activity. Basic Functions of the RADIUS Protocol The RADIUS architecture is based on a client-server model. It uses UDP on the transport layer. Transactions between the client and the server are authenticated, which is achieved by using a common secret key that is never sent through the network. Given the limited resources available to network devices, RADIUS facilitates and centralizes charging end users, provides some protection against active attacks by unauthorized users and it has great support from different network equipment vendors. Although RADIUS is a widely accepted protocol for the mechanisms of authentication, authorization and accounting, it has certain shortcomings that may be caused by the protocol itself or by its poor implementation. Architecture and Operation of the Diameter Protocol Diameter is a scalable protocol designed by the IETF working group in order to eliminate shortcomings and functional limitations of the RADIUS protocol and eventually to replace it in the near future. Most of the basic Diameter mechanisms and its
Directory of Open Access Journals (Sweden)
Gogna Paritosh
2013-12-01
Full Text Available 【Abstract】Objective: Metaphyseal-diaphyseal fractures of the distal radius are a major treatment dilemma and orthopaedic surgeons have to pay due consideration to restoration of anatomy of distal radius together with ro- tation of the radial shaft and maintenance of radial bow and interosseous space. We performed this study to evaluate the clinic-radiological outcome of metaphyseal-diaphyseal fractures of the distal radius treated with long volar locking plates. Methods: This prospective study involved 27 pa- tients (22 males and 5 females with metaphyseal-diaphy- seal fracture of the distal radius. Their mean age was (30.12± 11.48 years (range 19-52 years and the follow-up was 26.8 months (range 22-34 months. All patients underwent open reduction and internal fixation with a long volar locking plate. According to AO/OTA classification, there were 7 type A3, 13 type C2 and 7 type C3 fractures. Subjective assessment was done based on the disabilities of the arm, shoulder and hand (DASH questionnaire. Functional evaluation was done by measuring grip strength and range of motion around the wrist and the radiological determinants included radial angle, radial length, volar angle and ulnar variance. The final as- sessment was done according to Gartland and Werley scor- ing system. Results: Postoperative radiological parameters were well maintained throughout the trial, and there was signifi- cant improvement in the functional parameters from 6 weeks to final follow-up. The average DASH scores improved from 37.5 at 6 weeks to 4.2 at final follow-up. Final assessment using Gartland and Werley scoring system revealed 66.67% (n=18 excellent and 33.33% (n=9 good results. There was one case of superficial infection which responded to antibi- otics and another carpel tunnel syndrome which was ma- naged conservatively. Conclusion: Volar locking plate fixation for metaphy- seal-diaphyseal fractures of distal radius is associated with excellent to good
Cauchy's stress theory in a modern light
International Nuclear Information System (INIS)
Koenemann, Falk H
2014-01-01
The 180 year old stress theory by Cauchy is found to be insufficient to serve as a basis for a modern understanding of material behaviour. Six reasons are discussed in detail: (1) Cauchy's theory, following Euler, considers forces interacting with planes. This is in contrast to Newton's mechanics which considers forces interacting with radius vectors. (2) Bonds in solids have never been taken into account. (3) Cauchy's stress theory does not meet the minimum conditions for vector spaces because it does not have a metric. It is not a field theory, and not in the Euclidean space. (4) Cauchy's theory contains a hidden boundary condition that makes it less than general. (5) The current theory of stress is found to be at variance with the theory of potentials. (6) The theory is conceptually incompatible with thermodynamics for physical and geometrical reasons. (paper)
Nonperturbative perturbation theory
International Nuclear Information System (INIS)
Bender, C.M.
1989-01-01
In this talk we describe a recently proposed graphical perturbative calculational scheme for quantum field theory. The basic idea is to expand in the power of the interaction term. For example, to solve a λφ 4 theory in d-dimensional space-time, we introduce a small parameter δ and consider a λ(φ 2 ) 1+δ field theory. We show how to expand such a theory as a series in powers of δ. The resulting perturbation series appears to have a finite radius of convergence and numerical results for low-dimensional models are good. We have computed the two-point and four-point Green's functions to second order in powers of δ and the 2n-point Green's functions (n>2) to order δ. We explain how to renormalize the theory and show that, to first order in powers of δ, when δ>0 and d≥4 the theory is free. This conclusion remains valid to second order in powers of δ, and we believe that it remains valid to all orders in powers of δ. The new perturbative scheme is consistent with global supersymmetry invariance. We examine a two-dimensional supersymmetric quantum field theory in which we do not know of any other means for doing analytical calculations. We illustrate the power of this new technique by computing the ground-state energy density E to second order in this new perturbation theory. We show that there is a beautiful and delicate cancellation between infinite classes of graphs which leads to the result that E=0. (orig.)
Limits on the effective quark radius from inclusive ep scattering at HERA
Energy Technology Data Exchange (ETDEWEB)
Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Sciences; Collaboration: ZEUS Collaboration; and others
2016-04-15
The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current ep scattering corresponding to a luminosity of around 1 fb{sup -1} have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive ep data is presented; simultaneous fits of parton distribution functions together with contributions of ''new physics'' processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is 0.43.10{sup -16} cm.
Observations of the severity of notch-root radius in initiation of subcritical crack growth
International Nuclear Information System (INIS)
Reuter, W.G.; Eiholzer, C.R.; Tupper, M.A.
1981-01-01
Slow bend tests were conducted on Charpy specimens containing precracks or machined notches of 0.10 or 0.25 mm radius. The test specimens were fabricated from three heats of annealed Type 304 stainless steel. The purpose of these tests was to examine the effects of notch root radius, in very ductile materials, on initiation of subcritical crack growth. In addition, it was intended to establish the critical values of J, COD, etc. for the single-edge notch specimen for comparison with results obtained from specimens containing surface flaws. This paper will briefly describe only those results of the calculation for J. The tests were monitored by acoustic emission to identify the load corresponding to initiation of subcritical crack growth, by a crack-opening displacement gage (COD), by cross-head displacement, and by stop-action photography
International Nuclear Information System (INIS)
Knudsen, W.C.
1992-01-01
The effect of finite grid radius and thickness on the electron current measured by planar retarding potential analyzers (RPAs) is analyzed numerically. Depending on the plasma environment, the current is significantly reduced below that which is calculated using a theoretical equation derived for an idealized RPA having grids with infinite radius and vanishingly small thickness. A correction factor to the idealized theoretical equation is derived for the Pioneer Venus (PV) orbiter RPA (ORPA) for electron gases consisting of one or more components obeying Maxwell statistics. The error in density and temperature of Maxwellian electron distributions previously derived from ORPA data using the theoretical expression for the idealized ORPA is evaluated by comparing the densities and temperatures derived from a sample of PV ORPA data using the theoretical expression with and without the correction factor
Cloud Liquid Water, Mean Droplet Radius and Number Density Measurements Using a Raman Lidar
Whiteman, David N.; Melfi, S. Harvey
1999-01-01
A new technique for measuring cloud liquid water, mean droplet radius and droplet number density is outlined. The technique is based on simultaneously measuring Raman and Mie scattering from cloud liquid droplets using a Raman lidar. Laboratory experiments on liquid micro-spheres have shown that the intensity of Raman scattering is proportional to the amount of liquid present in the spheres. This fact is used as a constraint on calculated Mie intensity assuming a gamma function particle size distribution. The resulting retrieval technique is shown to give stable solutions with no false minima. It is tested using Raman lidar data where the liquid water signal was seen as an enhancement to the water vapor signal. The general relationship of retrieved average radius and number density is consistent with traditional cloud physics models. Sensitivity to the assumed maximum cloud liquid water amount and the water vapor mixing ratio calibration are tested. Improvements to the technique are suggested.
A clinical study evaluating bone mineral mass in the radius during skeletal growth
International Nuclear Information System (INIS)
Hagino, Hiroshi
1989-01-01
Using 125-I single photon absorptiometry, bone mineral measurements were performed on 206 healthy Japanese children (2 to 19 years of age). Bone mineral content (BMC), bone width (BW) and BMC/BW values were determined for the radius at distal 1/6 site (metaphysis) and distal 1/3 site (diaphysis). BMC/BW values at both sites correlated well with body height and weight. Bone mass in the diaphysis (distal 1/3 site) increased linearly during the 2-19 years of skeletal growth, but bone mass in the metaphysis (1/6 site) increased steeply during the pubertal period. In children receiving glucocorticoid therapy, bone mass was reduced in proportion to the duration of drug administration. In children under anticonvulsant therapy, the yearly increse in bone mass was significantly low especially in those patients with poor physical activity levels. Bone mineral decrease in the radius occurred in the children with hypopituitalism, hypothyroidism (cretinism), hyperthyroidism and Turner's syndrome. (author)
Effect of perturbation of convective energy transport on the luminosity and radius of the sun
International Nuclear Information System (INIS)
Endal, A.S.; Twigg, L.W.
1982-01-01
The response of solar models to perturbations of the efficiency of convective energy transport is studied for a number of cases. Such perturbations primarily affect the shallow superadiabatic layer of the convective envelope (at depths 3 km below the photosphere). Independent of the details of the perturbation scheme, the resulting change in the solar radius (ΔR/R) is always very small compared to the change in luminosity (ΔL/L). This appears to be true for any physical mechanism of solar variability which operates in the outer layers of the convection zone. Changes of the solar radius have been inferred by Dunham et al. from historical observations of solar eclipses in 1715 and 1925. Considering the constraints on concurrent luminosity changes, this type of solar variability must be indicative of changes in the solar structure at substantial depths below the superadiabatic layer of the convective envelope
Limits on the effective quark radius from inclusive ep scattering at HERA
International Nuclear Information System (INIS)
Abramowicz, H.; Abt, I.; Adamczyk, L.
2016-04-01
The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current ep scattering corresponding to a luminosity of around 1 fb -1 have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive ep data is presented; simultaneous fits of parton distribution functions together with contributions of ''new physics'' processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is 0.43.10 -16 cm.
Limits on the effective quark radius from inclusive $ep$ scattering at HERA
Abramowicz, H; Adamczyk, L; Adamus, M; Antonelli, S; Aushev, V; Behnke, O; Behrens, U; Bertolin, A; Bloch, I; Boos, EG; Brock, I; Brook, NH; Brugnera, R; Bruni, A; Bussey, PJ; Caldwell, A; Capua, M; Catterall, CD; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cooper-Sarkar, AM; Corradi, M; Dementiev, RK; Devenish, RCE; Dusini, S; Foster, B; Gach, G; Gallo, E; Garfagnini, A; Geiser, A; Gizhko, A; Gladilin, LK; Golubkov, Yu A; Grzelak, G; Guzik, M; Hain, W; Hochman, D; Hori, R; Ibrahim, ZA; Iga, Y; Ishitsuka, M; Januschek, F; Jomhari, NZ; Kadenko, I; Kananov, S; Karshon, U; Kaur, P; Kisielewska, D; Klanner, R; Klein, U; Korzhavina, IA; Kotański, A; Kötz, U; Kovalchuk, N; Kowalski, H; Krupa, B; Kuprash, O; Kuze, M; Levchenko, BB; Levy, A; Limentani, S; Lisovyi, M; Lobodzinska, E; Löhr, B; Lohrmann, E; Longhin, A; Lontkovskyi, D; Lukina, OYu; Makarenko, I; Malka, J; Mohamad Idris, F; Mohammad Nasir, N; Myronenko, V; Nagano, K; Nobe, T; Nowak, RJ; Onishchuk, Yu; Paul, E; Perlański, W; Pokrovskiy, NS; Przybycien, M; Roloff, P; Ruspa, M; Saxon, DH; Schioppa, M; Schneekloth, U; Schörner-Sadenius, T; Shcheglova, LM; Shevchenko, R; Shkola, O; Shyrma, Yu; Singh, I; Skillicorn, IO; Słomiński, W; Solano, A; Stanco, L; Stefaniuk, N; Stern, A; Stopa, P; Sztuk-Dambietz, J; Tassi, E; Tokushuku, K; Tomaszewska, J; Tsurugai, T; Turcato, M; Turkot, O; Tymieniecka, T; Verbytskyi, A; Wan Abdullah, WAT; Wichmann, K; Wing, M; Yamada, S; Yamazaki, Y; Zakharchuk, N; Żarnecki, AF; Zawiejski, L; Zenaiev, O; Zhautykov, BO; Zotkin, DS; Bhadra, S; Gwenlan, C; Hlushchenko, O; Polini, A; Mastroberardino, A; Sukhonos, D
2016-01-01
The high-precision HERA data allows searches up to TeV scales for Beyond the Standard Model contributions to electron-quark scattering. Combined measurements of the inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering corresponding to a luminosity of around 1 fb$^{-1}$ have been used in this analysis. A new approach to the beyond the Standard Model analysis of the inclusive $ep$ data is presented; simultaneous fits of parton distribution functions together with contributions of "new physics" processes were performed. Results are presented considering a finite radius of quarks within the quark form-factor model. The resulting 95% C.L. upper limit on the effective quark radius is $0.43\\cdot 10^{-16}$ cm.
Joint polarization tracking and channel equalization based on radius-directed linear Kalman filter
Zhang, Qun; Yang, Yanfu; Zhong, Kangping; Liu, Jie; Wu, Xiong; Yao, Yong
2018-01-01
We propose a joint polarization tracking and channel equalization scheme based on radius-directed linear Kalman filter (RD-LKF) by introducing the butterfly finite-impulse-response (FIR) filter in our previously proposed RD-LKF method. Along with the fast polarization tracking, it can also simultaneously compensate the inter-symbol interference (ISI) effects including residual chromatic dispersion and polarization mode dispersion. Compared with the conventional radius-directed equalizer (RDE) algorithm, it is demonstrated experimentally that three times faster convergence speed, one order of magnitude better tracking capability, and better BER performance is obtained in polarization division multiplexing 16 quadrature amplitude modulation system. Besides, the influences of the algorithm parameters on the convergence and the tracking performance are investigated by numerical simulation.
Modelling the cutting edge radius size effect for force prediction in micro milling
DEFF Research Database (Denmark)
Bissacco, Giuliano; Hansen, Hans Nørgaard; Jan, Slunsky
2008-01-01
This paper presents a theoretical model for cutting force prediction in micro milling, taking into account the cutting edge radius size effect, the tool run out and the deviation of the chip flow angle from the inclination angle. A parameterization according to the uncut chip thickness to cutting...... edge radius ratio is used for the parameters involved in the force calculation. The model was verified by means of cutting force measurements in micro milling. The results show good agreement between predicted and measured forces. It is also demonstrated that the use of the Stabler's rule...... is a reasonable approximation and that micro end mill run out is effectively compensated by the deflections induced by the cutting forces....
Influences of nuclear containment radius on the aircraft impact force based on the Riera function
Energy Technology Data Exchange (ETDEWEB)
Zhang, T.; Wu, H., E-mail: abrahamhao@126.com; Fang, Q.; Gong, Z.M.
2015-11-15
Highlights: • A fine aircraft model of A320 was built and verified by available limited prototype impacting tests. • The influences of aircraft longitudinal crushing strength on the impact process were analyzed. • The influences of NPP containment radius on the impact force were numerically studied. • The Riera function was modified by considering the radius effect of NPP containment. - Abstract: The aircraft impact force directly influences the local failure and global response of the nuclear power plant (NPP) containment, while the existing theoretical models and the field tests were almost based on the flat target. In order to analyze the radius effect of the circular sectional containment on the impact force, a fine FE model of the commercial aircraft A320 was established and validated by the available limited full-scale F-4 Phantom impact experiment. In order to determine the force to crush the A320 FE model, the influences of aircraft longitudinal crushing strength on the impact process were analyzed based on the Riera function. Considering the containment decaying effect to aircraft impact velocity, the impact impulse was theoretically calculated, while the influences of the losses of mass and energy were not included. The numerical simulations of A320 aircrafts impacting on simplified NPP containments with different radii were conducted, which could well reproduce the airframe crushing and debris scattering. By comparison of the simulated impact impulses and the calculation values by the Riera function, the coefficients corresponding to different containment radii are derived and a fitting formula is obtained. Finally, an improved Riera function dependent on the dimensionless ratio of nuclear containment radius and aircraft wingspan is proposed.
Directory of Open Access Journals (Sweden)
Cojocaru Vasile
2014-06-01
Full Text Available In the thread root area of the threaded bolts submitted to axial loading occur local stresses, higher that nominal stresses calculated for the bolts. These local stresses can generate failure and can reduce the fatigue life of the parts. The paper is focused on the study of the influence of the thread root radius on the maximum local stresses. A large diameter trapezoidal bolt was subjected to a static analysis (axial loading using finite element simulation.
DISCOVERY AND ATMOSPHERIC CHARACTERIZATION OF GIANT PLANET KEPLER-12b: AN INFLATED RADIUS OUTLIER
International Nuclear Information System (INIS)
Fortney, Jonathan J.; Nutzman, Philip; Demory, Brice-Olivier; Désert, Jean-Michel; Buchhave, Lars A.; Charbonneau, David; Fressin, François; Rowe, Jason; Caldwell, Douglas A.; Jenkins, Jon M.; Marcy, Geoffrey W.; Isaacson, Howard; Howard, Andrew; Knutson, Heather A.; Ciardi, David; Gautier, Thomas N.; Batalha, Natalie M.; Bryson, Stephen T.; Howell, Steve B.; Everett, Mark
2011-01-01
We report the discovery of planet Kepler-12b (KOI-20), which at 1.695 ± 0.030 R J is among the handful of planets with super-inflated radii above 1.65 R J . Orbiting its slightly evolved G0 host with a 4.438 day period, this 0.431 ± 0.041 M J planet is the least irradiated within this largest-planet-radius group, which has important implications for planetary physics. The planet's inflated radius and low mass lead to a very low density of 0.111 ± 0.010 g cm –3 . We detect the occultation of the planet at a significance of 3.7σ in the Kepler bandpass. This yields a geometric albedo of 0.14 ± 0.04; the planetary flux is due to a combination of scattered light and emitted thermal flux. We use multiple observations with Warm Spitzer to detect the occultation at 7σ and 4σ in the 3.6 and 4.5 μm bandpasses, respectively. The occultation photometry timing is consistent with a circular orbit at e < 0.01 (1σ) and e < 0.09 (3σ). The occultation detections across the three bands favor an atmospheric model with no dayside temperature inversion. The Kepler occultation detection provides significant leverage, but conclusions regarding temperature structure are preliminary, given our ignorance of opacity sources at optical wavelengths in hot Jupiter atmospheres. If Kepler-12b and HD 209458b, which intercept similar incident stellar fluxes, have the same heavy-element masses, the interior energy source needed to explain the large radius of Kepler-12b is three times larger than that of HD 209458b. This may suggest that more than one radius-inflation mechanism is at work for Kepler-12b or that it is less heavy-element rich than other transiting planets.
Bone density of the radius, spine, and proximal femur in osteoporosis
International Nuclear Information System (INIS)
Mazess, R.B.; Barden, H.; Ettinger, M.; Schultz, E.
1988-01-01
Bone mineral density (BMD) was measured in 140 normal young women (aged 20 to 39 years) and in 423 consecutive women over age 40 referred for evaluation of osteoporosis. Lumbar spine and proximal femur BMD was measured using dual-photon absorptiometry ( 153 Gd), whereas the radius shaft measurement used single-photon absorptiometry ( 125 I). There were 324 older women with no fractures, of which 278 aged 60 to 80 years served as age-matched controls. There were 99 women with fractures including 32 with vertebral and 22 with hip fractures. Subsequently, another 25 women with hip fractures had BMD measured in another laboratory; their mean BMD was within 2% of that of the original series. The mean age in both the nonfracture and fracture groups was 70 +/- 5 years. The BMD in the age-matched controls was 20% to 25% below that of normal young women for the radius, spine, and femur, but the Ward's triangle region of the femur showed even greater loss (35%). The mean BMD at all sites in the crush fracture cases was about 10% to 15% below that of age-matched controls. Spinal abnormality was best discriminated by spine and femoral measurements (Z score about 0.9). In women with hip fractures, the BMD was 10% below that of age-matched controls for the radius and the spine, and the BMD for the femoral sites was about 25% to 30% below that of age-matched control (Z score about 1.6). Femoral densities gave the best discrimination of hip fracture cases and even reflected spinal osteopenia. In contrast, neither the spine nor the radius reflected the full extent of femoral osteopenia in hip fracture
Huish, Eric G; Coury, John G; Ibrahim, Mohamed A; Trzeciak, Marc A
2017-04-01
The purpose of this study is to compare radiographic outcomes of patients treated with dorsal spanning plates with previously reported normal values of radiographic distal radius anatomy and compare the results with prior publications for both external fixation and internal fixation with volar locked plates. Patients with complex distal radius fractures including dorsal marginal impaction pattern necessitating dorsal distraction plating at the discretion of the senior authors (M.A.T. and M.A.I.) from May 30, 2013, to December 29, 2015, were identified and included in the study. Retrospective chart and radiograph review was performed on 19 patients, 11 male and 8 female, with mean age of 47.83 years (22-82). No patients were excluded from the study. All fractures united prior to plate removal. The average time the plate was in place was 80.5 days (49-129). Follow-up radiographs showed average radial inclination of 20.5° (13.2°-25.5°), radial height of 10.7 mm (7.5-14 mm), ulnar variance of -0.3 mm (-2.1 to 3.1 mm), and volar tilt of 7.9° (-3° to 15°). One patient had intra-articular step-off greater than 2 mm. Dorsal distraction plating of complex distal radius fractures yields good radiographic results with minimal complications. In cases of complex distal radius fractures including dorsal marginal impaction where volar plating is not considered adequate, a dorsal distraction plate should be considered as an alternative to external fixation due to reduced risk for infection and better control of volar tilt.
Long-term evolution of broken wakefields in finite radius plasmas
Lotov, Konstantin; Petrenko, Alexey
2014-01-01
A novel effect of fast heating and charging a finite-radius plasma is discovered in the context of plasma wakefield acceleration. As the plasma wave breaks, the most of its energy is transferred to plasma electrons which create strong charge-separation electric field and azimuthal magnetic field around the plasma. The slowly varying field structure is preserved for hundreds of wakefield periods and contains (together with hot electrons) up to 80% of the initial wakefield energy.
Review of Experimental and Theoretical Status of the Proton Radius Puzzle
Energy Technology Data Exchange (ETDEWEB)
Hill, Richard J. [TRIUMF
2017-01-01
The discrepancy between the measured Lamb shift in muonic hydrogen and expectations from electron-proton scattering and regular hydrogen spectroscopy has become known as the proton radius puzzle, whose most “mundane” resolution requires a > 5σ shift in the value of the fundamental Rydberg constant. I briefly review the status of spectroscopic and scattering measurements, recent theoretical developments, and implications for fundamental physics.
Pilot fire radius size and its variation regarding the uncertainty in fire risk assessment
International Nuclear Information System (INIS)
Argirov, J.
1998-01-01
The impact of a combustible load with limited amount of heat on the characteristics of fire generated local environment is considered. The combustible load apportionment on the floor and its ability to release the heat at a different rate regarding the temperatures and heat flux in zones formed in the NPP compartments is studied using calculations. Several ways of variation of a pilot fire radius in the same range are compared. (author)
Magnetic nanoparticles formed in glasses co-doped with iron and larger radius elements
Edelman , Irina; Ivanova , Oxana; Ivantsov , Ruslan; Velikanov , D.; Zabluda , V.; Zubavichus , Y.; Veligzhanin , A.; Zaikovskiy , V.; Stepanov , S.; Artemenko , Alla; Curély , Jacques; Kliava , Janis
2012-01-01
International audience; A new type of nanoparticle-containing glasses based on borate glasses co-doped with low contents of iron and larger radius elements, Dy, Tb, Gd, Ho, Er, Y, and Bi, is studied. Heat treatment of these glasses results in formation of magnetic nanoparticles, radically changing their physical properties. Transmission electron microscopy and synchrotron radiation-based techniques: x-ray diffraction, extended x-ray absorption fine structure, x-ray absorption near-edge struct...
THE IMPACT OF SURFACE TEMPERATURE INHOMOGENEITIES ON QUIESCENT NEUTRON STAR RADIUS MEASUREMENTS
Energy Technology Data Exchange (ETDEWEB)
Elshamouty, K. G.; Heinke, C. O.; Morsink, S. M.; Stevens, A. L. [Department of Physics, University of Alberta, CCIS 4-181, Edmonton, AB T6G 2E1 (Canada); Bogdanov, S., E-mail: alshamou@ualberta.ca [Columbia Astrophysics Laboratory, Columbia University, 550 West 120th Street, NY 10027 (United States)
2016-08-01
Fitting the thermal X-ray spectra of neutron stars (NSs) in quiescent X-ray binaries can constrain the masses and radii of NSs. The effect of undetected hot spots on the spectrum, and thus on the inferred NS mass and radius, has not yet been explored for appropriate atmospheres and spectra. A hot spot would harden the observed spectrum, so that spectral modeling tends to infer radii that are too small. However, a hot spot may also produce detectable pulsations. We simulated the effects of a hot spot on the pulsed fraction and spectrum of the quiescent NSs X5 and X7 in the globular cluster 47 Tucanae, using appropriate spectra and beaming for hydrogen atmosphere models, incorporating special and general relativistic effects, and sampling a range of system angles. We searched for pulsations in archival Chandra HRC-S observations of X5 and X7, placing 90% confidence upper limits on their pulsed fractions below 16%. We use these pulsation limits to constrain the temperature differential of any hot spots, and to then constrain the effects of possible hot spots on the X-ray spectrum and the inferred radius from spectral fitting. We find that hot spots below our pulsation limit could bias the spectroscopically inferred radius downward by up to 28%. For Cen X-4 (which has deeper published pulsation searches), an undetected hot spot could bias its inferred radius downward by up to 10%. Improving constraints on pulsations from quiescent LMXBs may be essential for progress in constraining their radii.
THE IMPACT OF SURFACE TEMPERATURE INHOMOGENEITIES ON QUIESCENT NEUTRON STAR RADIUS MEASUREMENTS
International Nuclear Information System (INIS)
Elshamouty, K. G.; Heinke, C. O.; Morsink, S. M.; Stevens, A. L.; Bogdanov, S.
2016-01-01
Fitting the thermal X-ray spectra of neutron stars (NSs) in quiescent X-ray binaries can constrain the masses and radii of NSs. The effect of undetected hot spots on the spectrum, and thus on the inferred NS mass and radius, has not yet been explored for appropriate atmospheres and spectra. A hot spot would harden the observed spectrum, so that spectral modeling tends to infer radii that are too small. However, a hot spot may also produce detectable pulsations. We simulated the effects of a hot spot on the pulsed fraction and spectrum of the quiescent NSs X5 and X7 in the globular cluster 47 Tucanae, using appropriate spectra and beaming for hydrogen atmosphere models, incorporating special and general relativistic effects, and sampling a range of system angles. We searched for pulsations in archival Chandra HRC-S observations of X5 and X7, placing 90% confidence upper limits on their pulsed fractions below 16%. We use these pulsation limits to constrain the temperature differential of any hot spots, and to then constrain the effects of possible hot spots on the X-ray spectrum and the inferred radius from spectral fitting. We find that hot spots below our pulsation limit could bias the spectroscopically inferred radius downward by up to 28%. For Cen X-4 (which has deeper published pulsation searches), an undetected hot spot could bias its inferred radius downward by up to 10%. Improving constraints on pulsations from quiescent LMXBs may be essential for progress in constraining their radii.
Fixation via dorsal for complex fractures of radius distal with plate P
International Nuclear Information System (INIS)
Rojas, Sandra; Bocanegra, Sergio; Suarez, Fabio
2002-01-01
The existence of multiple alternatives in the handling of the complex fractures of the radius distal it constitutes a reflection of the challenge that these they represent as for the possibility of recovering an appropriate consistency to articulate and orientation and radial height. This prospective study included 13 patients assisted in the hospital military of Bogota, by means of internal fixation with plate π. This treatment alternative, it solves many present inconveniences with other methods and it allows the precocious postoperative rehabilitation
Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms
Directory of Open Access Journals (Sweden)
Ji Chen
2016-01-01
Full Text Available We present calculations of nuclear structure effects to the Lamb shift in light muonic atoms. We adopt a modern ab-initio approach by combining state-of-the-art nuclear potentials with the hyperspherical harmonics method. Our calculations are instrumental to the determination of nuclear charge radii in the Lamb shift measurements, which will shed light on the proton radius puzzle.
Local spectrum and local spectral radius of an operator at a fixed vector
Czech Academy of Sciences Publication Activity Database
Bračič, J.; Müller, Vladimír
2009-01-01
Roč. 194, č. 2 (2009), s. 155-162 ISSN 0039-3223 R&D Projects: GA ČR GA201/09/0473 Institutional research plan: CEZ:AV0Z10190503 Keywords : surjectivity spectrum * local spectrum * spectral radius Subject RIV: BA - General Mathematics Impact factor: 0.645, year: 2009 http://journals.impan.pl/cgi-bin/doi?sm194-2-3
Fracture configurations of the equine radius and tibia after a simulated kick
Fürst, Anton; Oswald, Susanne E; Jäggin, S; Piskoty, G; Michel, S; Auer, Jörg A
2008-01-01
The objective of this postmortem study was to determine the fracture configurations of the equine radius and tibia after a simulated kick. Fracture configurations of 35 radii and 36 tibiae from 19 adult horses were evaluated after a simulated kick in an experimental exvivo study. The bones were dissected, the proximal and distal ends were embedded in resin, fixed horizontally and preloaded in compression, and a steel impactor, designed to simulate a shod equine hoof, was dropped from a height...
Is Bone Grafting Necessary in the Treatment of Malunited Distal Radius Fractures?
Disseldorp, Dominique J. G.; Poeze, Martijn; Hannemann, Pascal F. W.; Brink, Peter R. G.
2015-01-01
Background Open wedge osteotomy with bone grafting and plate fixation is the standard procedure for the correction of malunited distal radius fractures. Bone grafts are used to increase structural stability and to enhance new bone formation. However, bone grafts are also associated with donor site morbidity, delayed union at bone–graft interfaces, size mismatch between graft and osteotomy defect, and additional operation time. Purpose The goal of this study was to assess bone healing and secondary fracture displacement in the treatment of malunited distal radius fractures without the use of bone grafting. Methods Between January 1993 and December 2013, 132 corrective osteotomies and plate fixations without bone grafting were performed for malunited distal radius fractures. The minimum follow-up time was 12 months. Primary study outcomes were time to complete bone healing and secondary fracture displacement. Preoperative and postoperative radiographs during follow-up were compared with each other, as well as with radiographs of the uninjured side. Results All 132 osteotomies healed. In two cases (1.5%), healing took more than 4 months, but reinterventions were not necessary. No cases of secondary fracture displacement or hardware failure were observed. Significant improvements in all radiographic parameters were shown after corrective osteotomy and plate fixation. Conclusion This study shows that bone grafts are not required for bone healing and prevention of secondary fracture displacement after corrective osteotomy and plate fixation of malunited distal radius fractures. Level of evidence Therapeutic, level IV, case series with no comparison group PMID:26261748
International Nuclear Information System (INIS)
Ku Sarah Syahidah Ku Muhamad
2012-01-01
Food irradiation is one of the most applicable methods that have been used in food industry especially to preserve food. Besides preservation of food, irradiation can also reduce microorganism, inhibit budding and others. However, this method can be misused by some irresponsible organization or person such as irradiate the food over the dose limit value. Therefore, the detection method is important to detect any misused in irradiation method. The objective of this research is to identify any changes in the structure of amylopectin by using radius gyration technique. Besides that, the viscosity of the sample is also determined by using Rheometer. The last objective of this research is to find a relationship between radius gyration and irradiation dose can be determined. Amylopectin and cassava powder were the sample in this research. The samples were irradiated in the gamma-cell at 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, and 10.0 kGy doses. 0 kGy were the controlled sample. The sample were made into gel to analysed using Rheometer and Small Angle X-ray Scattering (SAXS). The viscosity of the sample were analysed by using Rheometer while the radius gyration of the sample were analysed by using SAXS. Hence, the result of this experiment is, the viscosity of amylopectin reduces as the doses increases. But, at 10 kGy, the viscosity of the cassava starch was increased significantly. For the SAXS analysis, it is shows that the graph for amylopectin were fluctuates. While, for cassava starch the radius gyration increases with doses. Hence, the rheometer technique is suitable to be develop as a detection method in food irradiation. Further research should be done to improve the detection technique in food irradiation. (author)
On the Bonsall cone spectral radius and the approximate point spectrum
Czech Academy of Sciences Publication Activity Database
Müller, Vladimír; Peperko, A.
2017-01-01
Roč. 37, č. 10 (2017), s. 5337-5354 ISSN 1078-0947 R&D Projects: GA ČR(CZ) GA17-00941S Institutional support: RVO:67985840 Keywords : Bonsall's cone spectral radius * local spectral radii * approximate point spectrum Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.099, year: 2016 http://aimsciences.org/ journals /displayArticlesnew.jsp?paperID=14323
Mid-term functional outcome after the internal fixation of distal radius fractures
Directory of Open Access Journals (Sweden)
Phadnis Joideep
2012-01-01
Full Text Available Abstract Background Distal radius fracture is a common injury with a variety of operative and non-operative management options. There remains debate as to the optimal treatment for a given patient and fracture. Despite the popularity of volar locking plate fixation, there are few large cohort or long term follow up studies to justify this modality. Our aim was to report the functional outcome of a large number of patients at a significant follow up time after fixation of their distal radius with a volar locking plate. Methods 180 patients with 183 fractures and a mean age of 62.4 years were followed up retrospectively at a mean of 30 months (Standard deviation = 10.4. Functional assessment was performed using the Disabilities of the Arm, Shoulder and Hand (DASH and modified MAYO wrist scores. Statistical analysis was performed to identify possible variables affecting outcome and radiographs were assessed to determine time to fracture union. Results The median DASH score was 2.3 and median MAYO score was 90 for the whole group. Overall, 133 patients (74% had a good or excellent DASH and MAYO score. Statistical analysis showed that no specific variable including gender, age, fracture type, post-operative immobilisation or surgeon grade significantly affected outcome. Complications occurred in 27 patients (15% and in 11 patients were major (6%. Conclusion This single centre large population series demonstrates good to excellent results in the majority of patients after volar locking plate fixation of the distal radius, with complication rates comparable to other non-operative and operative treatment modalities. On this basis we recommend this mode of fixation for distal radius fractures requiting operative intervention.
DEFF Research Database (Denmark)
Bazot, M.; Ireland, M.J.; Huber, D.
2011-01-01
Sco. We observed the star during 12 nights with HARPS for seismology and used the PAVO beam-combiner at CHARA for interferometry. An average large frequency separation 134.4 ± 0.3 μHz and angular and linear radiuses of 0.6759 ± 0.0062 mas and 1.010 ± 0.009 Rsun were estimated. We used these values...
Theoretical calculation of rapid x-ray transients and radius expansion
International Nuclear Information System (INIS)
Starrfield, S.; Sparks, W.; Truran, J.; Kenyon, S.
1984-01-01
We present the results of a calculation of a thermonuclear runaway on a 10 km neutron star which produced a precursor, radius expansion, and after the envelope had begun to shrink, a seconds x-ray burst about 2500 second later. Although such an event has not yet been observed, decreasing the initial envelope mass should bring the calculations into better agreement with the observations
Unitarity limits on the mass and radius of dark matter particles
Griest, Kim; Kamionkowski, Marc
1989-01-01
Using partial wave unitarity and the observed density of the Universe, it is show that a stable elementary particle which was once in thermal equilibrium cannot have a mass greater than 340 TeV. An extended object which was once in thermal equilibrium cannot have a radius less than 7.5 x 10(exp -7) fm. A lower limit to the relic abundance of such particles is also found.
A Revised Broad-line Region Radius and Black Hole Mass for the Narrow-line Seyfert 1 NGC 4051
DEFF Research Database (Denmark)
Denney, K. D.; Watson, L. C.; Peterson, B. M.
2009-01-01
) radius and the optical continuum luminosity—the R BLR-L relationship. Our new measurements of the lag time between variations in the continuum and Hß emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R BLR = 1.87+0.54 -0.50 light days and black hole mass of M...
Radius expansion bursts from the neutron star transient XTE J1701-462; a new distance estimate
Lin, D.; Homan, J.; Remillard, R.; Wijnands, R.
2007-01-01
A detailed spectral analysis of the second and third type-I X- ray bursts from the neutron star transient XTE J1701-462 (detected on July 20 and July 25, see also ATel #1165) reveals clear photospheric radius expansion in both of them. The bursts show radius expansion for about 2-3 seconds, with the
CSIR Research Space (South Africa)
Thejane, T
2012-01-01
Full Text Available number of segments and the radius-length mapping function were used. The use of a third order polynomial to further improve the relationship between the radius and the length of the ear canal is suggested for future research work....
The reliability of AO classification for distal radius fracture, using CT findings
International Nuclear Information System (INIS)
Nakanishi, Yasuaki; Ono, Hiroshi; Furuta, Kazuhiko; Fujitani, Ryoutarou; Ota, Hiroyoshi
2006-01-01
The purpose of this study was to assess the reliability of the AO (Association for the Study of Internal Fixation) classification of distal radius fracture, using plain radiographs and 2 cross-sectional computed tomographic (CT) surface images. Five observers independently classified 32 distal radius fractures into 9 groups under AO classification. We established 4 methods for observation. First, using only two-directional radiographs; second, four-directional radiographs; third, CT (axial view) with four-directional radiographs; and fourth, CT (axial and sagittal views) with four-directional radiographs. Kappa statistics were used to establish the relative level of agreement between the observers. Interobserver reliability was poor in both first and second methods in which only plain radiographs were used (κ=0.30 and 0.23, respectively). Furthermore, reliability did not increase in the third method with the addition of 1 CT surface image (κ=0.29). In the fourth method, with the addition of 2 cross-sectional CT surface images, the reliability increased to a moderate level (κ=0.44). Interobserver reliability of the AO system of the classification of distal radius fractures was observed on using 2 cross-sectional CT surface images with four-directional radiographs. (author)
Core-powered mass-loss and the radius distribution of small exoplanets
Ginzburg, Sivan; Schlichting, Hilke E.; Sari, Re'em
2018-05-01
Recent observations identify a valley in the radius distribution of small exoplanets, with planets in the range 1.5-2.0 R⊕ significantly less common than somewhat smaller or larger planets. This valley may suggest a bimodal population of rocky planets that are either engulfed by massive gas envelopes that significantly enlarge their radius, or do not have detectable atmospheres at all. One explanation of such a bimodal distribution is atmospheric erosion by high-energy stellar photons. We investigate an alternative mechanism: the luminosity of the cooling rocky core, which can completely erode light envelopes while preserving heavy ones, produces a deficit of intermediate sized planets. We evolve planetary populations that are derived from observations using a simple analytical prescription, accounting self-consistently for envelope accretion, cooling and mass-loss, and demonstrate that core-powered mass-loss naturally reproduces the observed radius distribution, regardless of the high-energy incident flux. Observations of planets around different stellar types may distinguish between photoevaporation, which is powered by the high-energy tail of the stellar radiation, and core-powered mass-loss, which depends on the bolometric flux through the planet's equilibrium temperature that sets both its cooling and mass-loss rates.
Treatment of unstable intraarticular fracture of distal radius: POP casting with external fixation.
ur Rahman, Obaid; Khan, Mohammad Qadeem; Rasheed, Haroon; Ahmad, Saleem
2012-04-01
To compare radiological and functional outcome of external fixation and distraction with conservative Plaster of Paris (POP) cast for unstable intra-articular fractures of the distal radius. The study was conducted on 60 patients with unstable intra-articular fracture of distal radius who reported to emergency or outpatient Orthopaedic Surgery department of Benazir Bhutto Hospital, Rawalpindi, between March and August 2007. They were divided into two equal groups: Group A and Group B, treated by Plaster of Paris cast, and external fixation with distraction respectively. The functional outcome in terms of freedom from pain, range of movement, grip power and deformity, and the radiological outcome of radial length, incongruity and radio-ulnar joint position were analysed at three months follow-up using a 3-point scoring scale. In Group A, 1 (3%) patient showed excellent result, 8 (27%) patients good results, 19 (63%) patients fair results and 2 (7%) patients poor result. In Group B, 14 (47%) patients showed excellent results, 11 (37%) patients good results, 4 (13%) patients fair results and 1 (3%) patient poor result. The outcome score of the Group B patients was significantly better compared to the Group A patients (p value advantages over conventional Plaster of Paris cast in the treatment of unstable intra-articular fractures of distal radius.
Determination of recombination radius in Si for binary collision approximation codes
International Nuclear Information System (INIS)
Vizkelethy, Gyorgy; Foiles, Stephen M.
2016-01-01
Displacement damage caused by ions or neutrons in microelectronic devices can have significant effect on the performance of these devices. Therefore, it is important to predict not only the displacement damage profile, but also its magnitude precisely. Analytical methods and binary collision approximation codes working with amorphous targets use the concept of displacement energy, the energy that a lattice atom has to receive to create a permanent replacement. It was found that this “displacement energy” is direction dependent; it can range from 12 to 32 eV in silicon. Obviously, this model fails in BCA codes that work with crystalline targets, such as Marlowe. Marlowe does not use displacement energy; instead, it uses lattice binding energy only and then pairs the interstitial atoms with vacancies. Then based on the configuration of the Frenkel pairs it classifies them as close, near, or distant pairs, and considers the distant pairs the permanent replacements. Unfortunately, this separation is an ad hoc assumption, and the results do not agree with molecular dynamics calculations. After irradiation, there is a prompt recombination of interstitials and vacancies if they are nearby, within a recombination radius. In order to implement this recombination radius in Marlowe, we used the comparison of MD and Marlowe calculation in a range of ion energies in single crystal silicon target. The calculations showed that a single recombination radius of ∼7.4 Å in Marlowe for a range of ion energies gives an excellent agreement with MD.
Nodule detection in digital chest radiography: Summary of the radius chest trial
International Nuclear Information System (INIS)
Haakansson, M.; Baath, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Ruschin, M.; Tingberg, A.; Mattson, S.; Maansson, L. G.
2005-01-01
As a part of the Europe-wide research project 'Unification of physical and clinical requirements for medical X-ray imaging' - governed by the Radiological Imaging Unification Strategies (RADIUS) Group - a major image quality trial was conducted by members of the group. The RADIUS chest trial aimed at thoroughly examining various aspects of nodule detection in digital chest radiography, such as the effects of nodule location, system noise, anatomical noise, and anatomical background. The main findings of the RADIUS chest trial concerning the detection of a lung nodule with a size in the order of 10 mm can be summarised as: (1) the detectability of the nodule is largely dependent on its location in the chest, (2) the system noise has a minor impact on the detectability at the dose levels used today, (3) the disturbance of the anatomical noise is larger than that of the system noise but smaller than that of the anatomical background and (4) the anatomical background acts as noise to a large extent and is the major image component affecting the detectability of the nodule. (authors)
THE STELLAR HALOS OF MASSIVE ELLIPTICAL GALAXIES. II. DETAILED ABUNDANCE RATIOS AT LARGE RADIUS
Energy Technology Data Exchange (ETDEWEB)
Greene, Jenny E.; Murphy, Jeremy D.; Graves, Genevieve J.; Gunn, James E.; Raskutti, Sudhir [Department of Astrophysics, Princeton University, Princeton, NJ 08540 (United States); Comerford, Julia M.; Gebhardt, Karl [Department of Astronomy, UT Austin, 1 University Station C1400, Austin, TX 71712 (United States)
2013-10-20
We study the radial dependence in stellar populations of 33 nearby early-type galaxies with central stellar velocity dispersions σ{sub *} ∼> 150 km s{sup –1}. We measure stellar population properties in composite spectra, and use ratios of these composites to highlight the largest spectral changes as a function of radius. Based on stellar population modeling, the typical star at 2R{sub e} is old (∼10 Gyr), relatively metal-poor ([Fe/H] ≈ –0.5), and α-enhanced ([Mg/Fe] ≈ 0.3). The stars were made rapidly at z ≈ 1.5-2 in shallow potential wells. Declining radial gradients in [C/Fe], which follow [Fe/H], also arise from rapid star formation timescales due to declining carbon yields from low-metallicity massive stars. In contrast, [N/Fe] remains high at large radius. Stars at large radius have different abundance ratio patterns from stars in the center of any present-day galaxy, but are similar to average Milky Way thick disk stars. Our observations are thus consistent with a picture in which the stellar outskirts are built up through minor mergers with disky galaxies whose star formation is truncated early (z ≈ 1.5-2)
Acute flexor tendon injury following midshaft radius and ulna fractures in a paediatric patient
Directory of Open Access Journals (Sweden)
James Williams
2018-06-01
Full Text Available Delayed rupture of the extensor and flexor tendons are recognised complications of distal radius fractures. However, acute flexor tendon rupture in the context of forearm fractures is rare. A twelve-year-old female sustained midshaft fractures of the radius and ulna. Intra-operatively the flexor pollicis longus (FPL was found to be stripped from its musculotendinous junction at the level of the fracture fragment. The ruptured tendon was repaired using a modified Krackow technique at the time of fracture fixation. The repair was protected in plaster of Paris prior to referral to the paediatric hand clinic. The patient made a full recovery. Flexor tendon injury is a rare but potentially devastating consequence of acute forearm fractures. High energy trauma, significant volar angulation of the fracture fragment and clinical signs of flexor tendon injury should raise suspicion of this injury. A high index of suspicion in conjunction with repeat clinical examination of flexor tendon function should be performed before opting for closed management or intramedullary nailing in paediatric patients. Keywords: Acute, Flexor, Tendon, Fracture, Radius, Paediatric
Directory of Open Access Journals (Sweden)
Đurović Aleksandar
2005-01-01
Full Text Available Background. The use of orthoses is a questionable rehabilitation method for patients with the distal radius fracture at typical site. The aim of this study was to compare the effects of the rehabilitation on patients with radius fracture at the typical site, who wore circumferential static wrist orthoses, with those who did not wear them. Methods. Thirty patients were divided into 3 equal groups, 2 experimental groups, and 1 control group. The patients in the experimental groups were given the rehabilitation program of wearing serially manufactured (off-the-shelf, as well as custom-fit orthoses. Those in the control group did not wear wrist orthoses. Evaluation parameters were pain, edema, the range of the wrist motion, the quality of cylindrical, spherical, and pinch-spherical grasp, the strength of pinch and hand grasp, and patient's assessment of the effects of rehabilitation. Results. No significant difference in the effects of rehabilitation on the patients in experimental groups as opposed to control group was found. Patients in the first experimental group, and in control group were more satisfied with the effects of rehabilitation, as opposed to the patients in the second experimental group (p<0,05. Conclusion. The effects of circumferential static wrist orthoses in the rehabilitation of patients with distal radius fracture at the typical site were not clinically significant. There was no significant difference between the custom and off-the-shelf orthoses.
Leal-Junior, Arnaldo G.; Frizera, Anselmo; José Pontes, Maria
2018-03-01
Polymer optical fibers (POFs) are suitable for applications such as curvature sensors, strain, temperature, liquid level, among others. However, for enhancing sensitivity, many polymer optical fiber curvature sensors based on intensity variation require a lateral section. Lateral section length, depth, and surface roughness have great influence on the sensor sensitivity, hysteresis, and linearity. Moreover, the sensor curvature radius increase the stress on the fiber, which leads on variation of the sensor behavior. This paper presents the analysis relating the curvature radius and lateral section length, depth and surface roughness with the sensor sensitivity, hysteresis and linearity for a POF curvature sensor. Results show a strong correlation between the decision parameters behavior and the performance for sensor applications based on intensity variation. Furthermore, there is a trade-off among the sensitive zone length, depth, surface roughness, and curvature radius with the sensor desired performance parameters, which are minimum hysteresis, maximum sensitivity, and maximum linearity. The optimization of these parameters is applied to obtain a sensor with sensitivity of 20.9 mV/°, linearity of 0.9992 and hysteresis below 1%, which represent a better performance of the sensor when compared with the sensor without the optimization.
Geneva University - Measurement of the Lamb shift in muonic hydrogen: the proton radius puzzle
2010-01-01
GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 GENEVA 4 Tel: (022) 379 62 73 Fax: (022) 379 69 92 Wednesday 12 May 2010 PARTICLE PHYSICS SEMINAR at 17.00 hrs – Stückelberg Auditorium Measurement of the Lamb shift in muonic hydrogen: the proton radius puzzle Dr Aldo Antogninia , CREMA Collaboration, Max Planck Institute, Germany At the Paul Scherrer Institut, Switzerland, we have measured several 2S-2P transition frequencies in muonic hydrogen (µp) and deuterium (µd) by means of laser spectroscopy. This results in an order of magnitude improvement on the rms charge radius values of the proton and the deuteron. Additionally the Zemach radii and the deuteron polarizability are also inferred. The new proton radius value is deduced with a relative accuracy of 0.1% but strongly disagrees from CODATA. The origin of this discrepancy is not yet known. It may come from theo...
Critical radius and critical number of gas atoms for cavities containing a Van der Waals gas
International Nuclear Information System (INIS)
Coghlan, W.A.; Mansur, L.K.
1983-01-01
The effect of gas on void nucleation and growth is particularly important for structural materials in fusion reactors because of the high production of helium by neutron-induced transmutation reactions. Gas reduces the critical radius for bias driven growth and there is a critical number of gas atoms, n/sub g/*, at which the critical radius is reduced essentially to zero. The significance of this is that the time interval to the accumulation of n/sub g/* gas atoms may determine the time to the onset of bias driven swelling where n/sub g/* is large. In previous papers these critical quantities were given for an ideal gas. Recently, we presented the results for a Van der Waals gas. Here the derivation of these relations is presented and further results of calculations are given. At low temperatures (high pressures) the results depart from those of the ideal gas, with the critical number affected more strongly than the critical radius. Comparisons are made with earlier calculations
Laser confocal measurement system for curvature radius of lenses based on grating ruler
Tian, Jiwei; Wang, Yun; Zhou, Nan; Zhao, Weirui; Zhao, Weiqian
2015-02-01
In the modern optical measurement field, the radius of curvature (ROC) is one of the fundamental parameters of optical lens. Its measurement accuracy directly affects the other optical parameters, such as focal length, aberration and so on, which significantly affect the overall performance of the optical system. To meet the demand of measurement instruments for radius of curvature (ROC) with high accuracy in the market, we develop a laser confocal radius measurement system with grating ruler. The system uses the peak point of the confocal intensity curve to precisely identify the cat-eye and confocal positions and then measure the distance between these two positions by using the grating ruler, thereby achieving the high-precision measurement for the ROC. The system has advantages of high focusing sensitivity and anti-environment disturbance ability. And the preliminary theoretical analysis and experiments show that the measuring repeatability can be up to 0.8 um, which can provide an effective way for the accurate measurement of ROC.
Sinicropi, Stefano M; Su, Brian W; Raia, Frank J; Parisien, May; Strauch, Robert J; Rosenwasser, Melvin P
2005-03-01
Dorsal plating of distal radius fractures with titanium plates has resulted in clinically observed tenosynovitis and tendon rupture. The goal of this study was to investigate whether titanium-based implants result in more extensor tendon inflammation than matched stainless-steel implants in a canine fracture model. An osteotomy was created in the distal radius of 18 beagles and fixed with 2.7-mm 4-hole plates composed of commercially pure titanium, titanium alloy (Ti-Al6-V4), or 316L stainless steel. Animals were killed at an average of 4 months. Tendon gliding was assessed by applying a force at the extensor musculotendinous junction and noting gliding. Histologic grading (mild, moderate, severe) was based on cellular hypertrophy, hyperplasia, and leukocytic infiltration. Tendons glided freely in 100% stainless-steel specimens, 75% of titanium alloy, and 43% of commercially pure titanium groups. A severe inflammatory reaction was identified in 60% of the titanium alloy (Ti-A16-V4) group, 57% of the pure titanium group, and 0% of the stainless-steel group. Dorsal plating of the canine radius with commercially pure titanium or titanium alloy implants produced a greater inflammatory peritendinous response than matched stainless-steel implants.
Directory of Open Access Journals (Sweden)
Chandrashekhar V. Mudgal
2017-04-01
Full Text Available BACKGROUND A study was done to evaluate the effect of the ligamentotaxis in the management of intraarticular fractures of the distal radius. MATERIALS AND METHODS 34 patients were studied prospectively between March 2014 and February 2016. All patients had intraarticular fracture of distal end of radius and all were treated with ligamentotaxis after closed reduction with fluoroscopic guidance. The follow-up period was 12 months. At the time of surgery, the mean age was 45.29 years. RESULTS In all fracture cases, the mean of fracture union was 5.8 weeks. During the final follow-up, the mean range of motion was 55.30 in flexion, 56.60 in extension, 21.0 in ulnar deviation, 9.00 in radial deviation, 70.30 in pronation and 67.10 in supination. According to the scoring system of Gartland and Werley, the clinical and functional outcomes showed that 15 patients (44.1% had excellent results, 14 (41.1% had good results, 3 (8.8% had fair results and 2 (5.8% had poor results. CONCLUSION Closed reduction under fluoroscopic image guidance and the ligamentotaxis is useful and effective in the treatment of intraarticular fractures of the distal radius.
Directory of Open Access Journals (Sweden)
G. Esteve-Asensio
2009-01-01
Full Text Available We propose and compare three novel heuristics for the calculation of the optimal cell radius in mobile networks based on Wideband Code Division Multiple Access (WCDMA technology. The proposed heuristics solve the problem of the load assignment and cellular radius calculation. We have tested our approaches with experiments in multiservices scenarios showing that the proposed heuristics maximize the cell radius, providing the optimum load factor assignment. The main application of these algorithms is strategic planning studies, where an estimation of the number of Nodes B of the mobile operator, at a national level, is required for economic analysis. In this case due to the large number of different scenarios considered (cities, towns, and open areas other methods than simulation need to be considered. As far as we know, there is no other similar method in the literature and therefore these heuristics may represent a novelty in strategic network planning studies. The proposed heuristics are implemented in a strategic planning software tool and an example of their application for a case in Spain is presented. The proposed heuristics are used for telecommunications regulatory studies in several countries.
International Nuclear Information System (INIS)
Edenstrasser, J.W.
1995-01-01
A multiple time-scale derivative expansion scheme is applied to the dimensionless Fokker--Planck equation and to Maxwell's equations, where the parameter range of a typical fusion plasma was assumed. Within kinetic theory, the four time scales considered are those of Larmor gyration, particle transit, collisions, and classical transport. The corresponding magnetohydrodynamic (MHD) time scales are those of ion Larmor gyration, Alfven, MHD collision, and resistive diffusion. The solution of the zeroth-order equations results in the force-free equilibria and ideal Ohm's law. The solution of the first-order equations leads under the assumption of a weak collisional plasma to the ideal MHD equations. On the MHD-collision time scale, not only the full set of the MHD transport equations is obtained, but also turbulent terms, where the related transport quantities are one order in the expansion parameter larger than those of classical transport. Finally, at the resistive diffusion time scale the known transport equations are arrived at including, however, also turbulent contributions. copyright 1995 American Institute of Physics
Physics of the dense Z-pinch in theory and in experiment with application to fusion reactor
Energy Technology Data Exchange (ETDEWEB)
Haines, M.G. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.)
1982-01-01
A new generation of Z-pinches employing high voltage, high current pulsed lines as power sources produce dense hot plasmas with enhanced stability properties. Three methods of Z-pinch formation are currently in use: (1) cylindrical collapse and compression of a pre-ionised gas; (2) laser initiation and Joule heating of a gas embedded pinch, and (3) hollow gas puff and subsequent collapse to the axis. The first two experimental conditions are relevant for fusion. A calculation of energy balance for satisfying Lawson conditions with axial and radial energy losses and radiation loss shows that a current of approximately 10/sup 6/ A and a line density of 6 x 10/sup 18/ m/sup -1/ are required. This leads to two coincidences of physical quantities that are very favourable for controlled fusion. The first is that at this line density and under pressure balance the ratio of the ion Larmor radius to pinch is of order 1 so that a marked stabilisation of the configuration is expected. The second coincidence is that the current is only just below the Pease-Braginskii limit; this will permit the possibility or radiative collapse to attain the high density (approximately 4 x 10/sup 27/ m/sup -3/) and small radius (approximately 20 ..mu..m) required for a compact (0.1 m long) discharge.
Directory of Open Access Journals (Sweden)
Prabhati Rani Mishra
2016-12-01
Full Text Available BACKGROUND Most common fracture in elderly patients is distal radius fracture. The most common method of management is closed reduction and immobilisation. The aim of the study is to compare the analgesic effects of haematoma block and general anaesthesia for closed reduction of distal fracture of radius. MATERIALS AND METHODS A prospective randomised controlled study was carried out among 100 patients of age group between 15-70 years of either sex who had fracture distal radius between 2015-2016. The patients having multiple fractures, pathological fractures or suffering from any organic diseases were excluded from the study. After taking informed written consent, the patients were randomised into two equal groups. In group A, reduction of fracture was done following administration of IV propofol and in group B after infiltration with 2% lignocaine into fracture haematoma site. Pain score was compared by VAS before, during and after manipulation in both the groups. Time taken from presentation at emergency department to reduction and discharge from hospital was also compared. Statistical analysis was done by applying SPSS software. RESULTS 100 patients of mean age 42.5 years, male: female 43:57 with fracture distal radius were studied. Mean time from admission to fracture reduction in group A was 2.64±0.93 hours and in group B 0.90±0.45 hours (P=0.0001. Discharge time from hospital after reduction of fracture in group A was 4.24±0.94 hours and in group B 0.75±0.2 hours (P=0.0001. VAS during reduction in group A was 0 and in group B 0.98±0.8 (P=0.0001. 10 minutes after reduction VAS in group A was 2.28±0.24 and group B 0.72±0.45 (P=0.0001. CONCLUSION For closed reduction of distal radius fracture, haematoma block with lignocaine is safe and effective alternative to intravenous general anaesthesia with propofol.
Relativistic stars in vector-tensor theories
Kase, Ryotaro; Minamitsuji, Masato; Tsujikawa, Shinji
2018-04-01
We study relativistic star solutions in second-order generalized Proca theories characterized by a U (1 )-breaking vector field with derivative couplings. In the models with cubic and quartic derivative coupling, the mass and radius of stars become larger than those in general relativity for negative derivative coupling constants. This phenomenon is mostly attributed to the increase of star radius induced by a slower decrease of the matter pressure compared to general relativity. There is a tendency that the relativistic star with a smaller mass is not gravitationally bound for a low central density and hence is dynamically unstable, but that with a larger mass is gravitationally bound. On the other hand, we show that the intrinsic vector-mode couplings give rise to general relativistic solutions with a trivial field profile, so the mass and radius are not modified from those in general relativity.
International Nuclear Information System (INIS)
Rogister, A.
1998-01-01
We show that the large negative radial electric fields which are measured in front of the separatrix in H-mode discharges are easily explainable on the basis of the rigorous 'revisited' neoclassical theory, including finite Larmor radii and inertia effects that was published earlier (Rogister A 1994 Phys. Plasmas 1 619); the same theory naturally leads to sub-neoclassical energy transport and novel particle pinch terms. The calculation has so far been developed only in the high collisionality regime: step sizes comparable to gradient-scale sizes are therefore not required to explain observed properties! Based on the analysis, we conclude that the radial electric field profile develops a well in front of the separatrix when the plasma is unable to sustain ambipolar flows otherwise. (author)
DEFF Research Database (Denmark)
Wæver, Ole
2009-01-01
-empiricism and anti-positivism of his position. Followers and critics alike have treated Waltzian neorealism as if it was at bottom a formal proposition about cause-effect relations. The extreme case of Waltz being so victorious in the discipline, and yet being consistently mis-interpreted on the question of theory......, shows the power of a dominant philosophy of science in US IR, and thus the challenge facing any ambitious theorising. The article suggests a possible movement of fronts away from the ‘fourth debate' between rationalism and reflectivism towards one of theory against empiricism. To help this new agenda...
Matsuura, Yusuke; Kuniyoshi, Kazuki; Suzuki, Takane; Ogawa, Yasufumi; Sukegawa, Koji; Rokkaku, Tomoyuki; Takahashi, Kazuhisa
2014-11-01
Distal radius fracture, which often occurs in the setting of osteoporosis, can lead to permanent deformity and disability. Great effort has been directed toward developing noninvasive methods for evaluating the distal radius strength, with the goal of assessing fracture risk. The aim of this study was to evaluate distal radius strength using a finite element model and to gauge the accuracy of finite element model measurement using cadaver material. Ten wrists were obtained from cadavers with a mean age of 89.5 years at death. CT images of each wrist in an extended position were obtained. CT-based finite element models were prepared with Mechanical Finder software. Fracture on the models was simulated by applying a mechanical load to the palm in a direction parallel to the forearm axis, after which the fracture load and the site at which the fracture began were identified. For comparison, the wrists were fractured using a universal testing machine and the fracture load and the site of fracture were identified. The fracture load was 970.9 N in the finite element model group and 990.0 N in the actual measurement group. The site of the initial fracture was extra-articular to the distal radius in both groups. The finite element model was predictive for distal radius fracture when compared to the actual measurement. In this study, a finite element model for evaluation of distal radius strength was validated and can be used to predict fracture risk. We conclude that a finite element model is useful for the evaluation of distal radius strength. Knowing distal radius strength might avoid distal radius fracture because appropriate antiosteoporotic treatment can be initiated.
Oreopoulos, Lazaros
2004-01-01
The MODIS Level-3 optical thickness and effective radius cloud product is a gridded l deg. x 1 deg. dataset that is derived from aggregation and subsampling at 5 km of 1 km, resolution Level-2 orbital swath data (Level-2 granules). This study examines the impact of the 5 km subsampling on the mean, standard deviation and inhomogeneity parameter statistics of optical thickness and effective radius. The methodology is simple and consists of estimating mean errors for a large collection of Terra and Aqua Level-2 granules by taking the difference of the statistics at the original and subsampled resolutions. It is shown that the Level-3 sampling does not affect the various quantities investigated to the same degree, with second order moments suffering greater subsampling errors, as expected. Mean errors drop dramatically when averages over a sufficient number of regions (e.g., monthly and/or latitudinal averages) are taken, pointing to a dominance of errors that are of random nature. When histograms built from subsampled data with the same binning rules as in the Level-3 dataset are used to reconstruct the quantities of interest, the mean errors do not deteriorate significantly. The results in this paper provide guidance to users of MODIS Level-3 optical thickness and effective radius cloud products on the range of errors due to subsampling they should expect and perhaps account for, in scientific work with this dataset. In general, subsampling errors should not be a serious concern when moderate temporal and/or spatial averaging is performed.
Directory of Open Access Journals (Sweden)
Hossein Alimohammadi
2013-12-01
Full Text Available Introduction: Given the high prevalence of upper extremity fractures and increasing need to perform painless reduction in the emergency departments, the use of analgesic methods with fewer complications and more satisfaction appears to be essential. The aim of this study is comparison the nerve stimulator guided axillary block (NSAB with intravenous sedation in induction of analgesia for painless reduction of distal radius fractures. Methods: In the present randomized clinical trial, 60 patients (18-70 years of age suffered from distal radius fractures, were divided into two equal groups. One group received axillary nerve block by nerve stimulator guidance and the other procedural sedation and analgesia (PSA using midazolam/fentanyl. Onset of analgesia, duration of analgesic effect, total procedure time and pain scores were recorded using visual analogue scale (VAS and the outcomes were compared. Chi-squared and student t test were performed to evaluate differences between two groups. Results: Sixty patients were randomly divided into two groups (83.3% male. The mean age of patients was 31 ±0.7 years. While the onset of analgesia was significantly longer in the NSAB group, the mean total time of procedure was shorter than PSA (p<0.001. The NSAB group needed a shorter post-operative observation time (P<0.001. Both groups experienced equal pain relief before, during and after procedure (p>0.05. Conclusion: It seems that shorter post-operative monitoring time and consequently lesser total time of procedure, make nerve stimulator guided axillary block as an appropriate alternative for procedural sedation and analgesia in painless reduction of distal radius fractures in emergency department.
Ayhan, Cigdem; Turgut, Elif; Baltaci, Gul
2015-03-01
Scapular motion is closely integrated with arm motion. Injury to a distal segment requires compensatory changes in the proximal segments leading to alterations in scapular motion. Since the effects of distal injuries on scapular kinematics remain unknown, in the present study we investigated the influences on scapular motion in patients with distal injuries. Sixteen subjects with a history of distal radius fracture and 20 asymptomatic healthy subjects (controls) participated in the study. Three-dimensional scapular and humeral kinematic data were collected on all 3 planes of shoulder elevation: frontal, sagittal, and scapular. All testing was performed in a single session; therefore, the sensors remained attached to the participants for all testing. The position and orientation data of the scapula at 30°, 60°, 90°, and 120° humerothoracic elevation and 120°, 90°, 60°, and 30° lowering were used for statistical comparisons. Independent samples t-test was used to compare the scapular internal/external rotation, upward/downward rotation, and anterior/posterior tilt between the affected side of subjects with a distal radius fracture and the dominant side of asymptomatic subjects at the same stage of humerothoracic elevation. Scapular internal rotation was significantly increased at 30° elevation (P=0.01), 90° elevation (P=0.03), and 30° lowering (P=0.03), and upward rotation was increased at 30° and 60° elevation (Pplane elevation. Scapular upward rotation and anterior tilt were significantly increased during 30° lowering on both the scapular (P=0.002 and 0.02, respectively) and sagittal planes (P=0.01 and 0.02. respectively). Patients with distal radius fractures exhibit altered scapular kinematics, which may further contribute to the development of secondary musculoskeletal pathologies. Copyright © 2014 Elsevier Ltd. All rights reserved.
Kinetic theory of free electron lasers
Energy Technology Data Exchange (ETDEWEB)
Hafizi, B. [Naval Research Lab., Washington, DC (United States); Roberson, C.W. [Office of Naval Research, Arlington, VA (United States)
1995-12-31
We have developed a relativistic kinetic theory of free electron lasers (FELs). The growth rate, efficiency, filling factor and radius of curvature of the radiation wave fronts are determined. We have used the theory to examine the effects of beam compression on growth rate. The theory has been extended to include self field effects on FEL operation. These effects are particularly important in compact, low voltage FELs. The surprising result is that the self field contribution to the beam quality is opposite to the emittance contribution. Hence self fields can improve beam quality, particularly in compact, low voltage FELs.
Extended Holomorphic Anomaly in Gauge Theory
Krefl, Daniel
2011-01-01
The partition function of an N=2 gauge theory in the Omega-background satisfies, for generic value of the parameter beta=-eps_1/eps_2, the, in general extended, but otherwise beta-independent, holomorphic anomaly equation of special geometry. Modularity together with the (beta-dependent) gap structure at the various singular loci in the moduli space completely fixes the holomorphic ambiguity, also when the extension is non-trivial. In some cases, the theory at the orbifold radius, corresponding to beta=2, can be identified with an "orientifold" of the theory at beta=1. The various connections give hints for embedding the structure into the topological string.
On perturbation theory for distance dependent statistics.
Energy Technology Data Exchange (ETDEWEB)
Mashkevich, S V
1994-12-31
It is known that perturbation theory for anyons has to be modified near Bose statistics in order to get correct finite results. For ``distance dependent statistics`` or anyons with smeared flux tubes, perturbation theory is in principle applicable directly but gives results which hold for too small values of the statistical parameter and, in particular, are not valid as the flux tube radius tends to zero. In this paper we discuss the way to modify perturbation theory for this situation, which allows to obtain the appropriate results. (author). 6 refs.
[APPLICATION OF BUTTERFLY SHAPED LOCKING COMPRESSION PLATE IN COMPLEX DISTAL RADIUS FRACTURES].
Jiang, Zongyuan; Ma, Tao; Xia, Jiang; Hu, Caizhi; Xu, Lei
2014-06-01
To investigate the effectiveness of butterfly shaped locking compression plate for the treatment of complex distal radius fractures. Between June 2011 and January 2013, 20 cases of complex distal radius fractures were treated with butterfly shaped locking compression plate fixation. There were 11 males and 9 females with an average age of 54 years (range, 25-75 years). Injury was caused by falling in 10 cases, by traffic accident in 7 cases, and by falling from height in 3 cases. All of fractures were closed. According to AO classification system, there were 8 cases of type C1, 8 cases of type C2, and 4 cases of type C3. Of them, 9 cases had radial styloid process fracture, 4 cases had sigmoid notch fracture, and 7 cases had both radial styloid process fracture and sigmoid notch fracture. The mean interval between injury and operation was 5.2 days (range, 3-15 days). All incisions healed by first intention; no complications of infection and necrosis occurred. All cases were followed up 14 months on average (range, 10-22 months). All factures healed after 9.3 weeks on average (range, 6-11 weeks). No complications such as displacement of fracture, joint surface subsidence, shortening of the radius, and carpal tunnel syndrome were found during follow-up. At last follow-up, the mean palmar tilt angle was 10.2° (range, 7-15°), and the mean ulnar deviation angle was 21.8° (range, 17-24°). The mean range of motion of the wrist was 45.3° (range, 35-68°) in dorsal extension, 53.5° (range, 40-78°) in palmar flexion, 19.8° (range, 12-27°) in radial inclination, 26.6° (range, 18-31°) in ulnar inclination, 70.2° (range, 45-90°) in pronation, and 68.4° (range, 25-88°) in supination. According to the Dienst scoring system, the results were excellent in 8 cases, good in 10 cases, and fair in 2 cases, and the excellent and good rate was 90%. Treatment of complex distal radius fractures with butterfly shaped locking compression plate can reconstruct normal anatomic
International Nuclear Information System (INIS)
Araujo, Marcos A. de; Silva, Rubens; Lima, Emerson de; Pereira, Daniel P.; Oliveira, Paulo C. de
2009-01-01
We revisited the well known Khosrofian and Garetz inversion algorithm [Appl. Opt.22, 3406-3410 (1983)APOPAI0003-6935] that was developed to analyze data obtained by the application of the traveling knife-edge technique. We have analyzed the approximated fitting function that was used for adjusting their experimental data and have found that it is not optimized to work with a full range of the experimentally-measured data. We have numerically calculated a new set of coefficients, which makes the approximated function suitable for a full experimental range, considerably improving the accuracy of the measurement of a radius of a focused Gaussian laser beam
[ESTABLISHMENT OF A NEW RADIUS DEFECT MODEL BASED ON ULNA ANATOMICAL MEASUREMENT IN RABBITS].
Liu, Hanjiang; Guo, Ying; Mei, Wei
2016-02-01
To introduce a new bone defect model based on the anatomical measurement of radius and ulna in rabbits for offering a standard model for further tissue engineering research. Fifteen healthy 4-month-old New Zealand rabbits were selected for anatomic measurement and radiological measurement of the radius and ulna. Another 30 healthy 4-month-old New Zealand rabbits were randomly divided into groups A, B, and C (n=10). The radius bone defect was created bilaterally in 3 groups. In group A, the periosteum and interosseous membranes were fully removed with jig-saw by approach between extensor carpi radialis muscle and musculus extensor digitorum. The periosteum and interosseous membranes were fully removed in group B, and only periosteum was removed in group C with electric-saw by approach between extensor carpi radialis muscle and flexor digitorum profundus based on anatomical analysis results of ulnar and radial measurement. The gross observation, X-ray, micro-CT three-dimensional reconstruction, bone mineral density (BMD), and bone mineral content (BMC) were observed and recorded at immediate and 15 weeks after operation. HE staining and Masson staining were performed to observe bone formation in the defect areas. Blood vessel injury (1 rabbit), tendon injury (2 rabbits), postoperative hematoma (1 rabbit), and infection (1 rabbit) occurred in group A, postoperative infection (1 rabbit) in group C, and no postoperative complications in group B; the complication rate of group A (50%) was significantly higher than that of groups B (0%) and C (10%) (P0.05). HE staining and Masson staining results showed bone formation in group A, with structure disturbance and sclerosis. New bone formed in groups B and C, cartilage cells were observed in the center of bone cells. The radius bone defect model established by approach between extensor carpi radialis muscle and flexor digitorum profundus is an ideal model because of better exposures, less intra-operative blood loss, less
Gajdoš, R; Pilný, J; Pokorná, A
2016-01-01
PURPOSE OF THE STUDY Injury to the scapholunate ligament is frequently associated with a fracture of the distal radius. At present neither a unified concept of treatment nor a standard method of diagnosis in these concomitant injuries is available. The aim of the study was to evaluate a group of surgically treated patients with distal radius fractures in order to assess a contribution of combined conventional X-ray and intra-operative fluoroscopic examinations to the diagnosis of associated lesions and to compare short-term functional outcomes of sugically treated patients with those of patients treated conservatively. MATERIAL AND METHODS A group of patients undergoiong surgery for distal radius fractures using plate osteosynthesis was evaluated retrospectively. The peri-operative diagnosis of associated injury to the scapholunate ligament was based on pre-operative standard X-ray views and intra-operative fluoroscopy. The latter consisted of images of maximum radial and ulnar deviation as well as an image of the forearm in traction exerted manually along the long axis. All views were in postero-anterior projection. Results were read directly on the monitor of a fluoroscopic device after its calibration or were obtained by comparing the thickness of an attached Kirschner wire with the distance to be measured. Subsequently, pixels were converted to millimetres. When a scapholunate ligament injury was found and confirmed by examination of the contralateral wrist, the finding was verified by open reduction or arthroscopy. Both static and dynamic instabilities were treated together with the distal radius fracture at one-stage surgery. After surgery, the patients without ligament injury had the wrist immobilised for 4 weeks, then rehabilitation followed. In the patients with a damaged ligament, immobilisation in a short brace lasted until transarticular wires were removed. All patients were followed up for a year at least. At follow-up, the injured wrist was examined
Analysis of neutron flux depression across the pellet radius in CANDU fuel elements
International Nuclear Information System (INIS)
Sim, K.S.; Suk, H.C.
1998-08-01
The TUBRNP model, originally developed to perform the analysis of the flux depression across the pellet radius in LWR fuel elements, was improved for the application to CANDU fuel elements. The improved model was verified through comparison with existing CANDU model named FLUXDEP in prediction for various fuel conditions. A sensitivity study was also performed to investigate the effects on the flux depression of fuel initial enrichment and burnup, the contents of isotopes U-234 and U-236 and pellet diameter. (author). 9 refs., 8 figs
Determination of variations of the solar radius from solar eclipse observations
Sofia, S.; Dunham, D. W.; Fiala, A. D.
1980-01-01
This paper describes the method to determine the solar radius and its variations from observations made during total solar eclipses. In particular, the procedure to correct the spherical moon predictions for the effects of lunar mountains and valleys on the width and location of the path of totality is addressed in detail. The errors affecting this technique are addressed, a summary of the results of its application to three solar eclipses are presented, and the implications of the results on the constancy of the solar constant are described.
Abdelsalam, D. G.; Shaalan, M. S.; Eloker, M. M.; Kim, Daesuk
2010-06-01
In this paper a method is presented to accurately measure the radius of curvature of different types of curved surfaces of different radii of curvatures of 38 000,18 000 and 8000 mm using multiple-beam interference fringes in reflection. The images captured by the digital detector were corrected by flat fielding method. The corrected images were analyzed and the form of the surfaces was obtained. A 3D profile for the three types of surfaces was obtained using Zernike polynomial fitting. Some sources of uncertainty in measurement were calculated by means of ray tracing simulations and the uncertainty budget was estimated within λ/40.
Alignment Compensation for Bending Radius in TT40 and TI 8 Transfer Line Magnets
Weterings, W
2003-01-01
The BEATCH file for the TI 8 transfer lines specifies the position of the bending magnets assuming that the beam enters and exits at the centre of the vacuum pipe. In order to distribute the deflected beam evenly inside the vacuum tube, the alignment has to be compensated by moving the magnets half of the beam deflection away from the centre of the bending radius. In this note the saggitas of the various TT40 and TI 8 magnets are calculated and the alignment displacements tabulated for future reference.
Alignment Compensation for Bending Radius in TI 2 Transfer Line Magnets
Weterings, W
2004-01-01
The optics file for the TI 2 transfer lines specifies the position of the bending magnets assuming that the beam enters and exists at the centre of the vacuum pipe. In order to disbribute the deflected beam evenly inside the vacuum tube, the alignment has to be compensated by moving the magnets half of the beam deflection away from the centre of the bending radius. In this note the saggitas of the various TI 2 magnets are calculated and the alignment displacements tabulated for future reference.
Yang, Xiang; Zhao, You-ming; Chen, Lin; Ye, Cong-cong; Guo, Wei-jun; Wang, Bo
2013-12-01
To compare efficacy of unilateral external fixators and locking compression plates in treating type C fractures of the distal radius. From January 2009 to June 2010, 76 patients with distal radius fracture were treated with LCP and external fixators, 54 patients were followed up. Among them, 29 cases were male and 25 cases were female with an average age of 45.31 (ranged, 24 to 68) years old. There were 29 patients in LCP group. According to AO classification, 8 cases were type C1, 7 cases were type C2 and 14 cases were type C3. There were 25 cases in external fixators group. According to AO classification, 6 cases were type C1, 8 cases were type C2 and 11 cases were type C3. Radial height, volar tilt and radial inclination were compared, advanced Gartland-Werley scoring were used to assessed wrist joint function after 6 and 12 months' following up. Two cases were suffered from nail infection in external fixators group. Fifty-four patients were followed up from 12 to 24 months with an average of 21.3 months. Radial height was (9.60 +/- 0.72) mm, volar tilt was (9.55 +/- 0.80) degrees and radial inclination was (21.40 +/- 0.78) degrees in LCP group,while those were (9.40 +/- 0.70) mm, (9.47 +/- 0.71) degrees and (21.20 +/- 0.73) degrees in external fixtors group, and with no statistical significance (P>0.05). Advanced Gartland-Werley score after 6 months' following up was 3.31 +/- 1.17 in LCP group, 5.56 +/- 1.58 in external fixtors group, and with significant difference (t=-5.99,Pmeaning (t=-1.55, P>0.05). LCP and external fixtors can receive good curative effects in treating type C distal radius fracture, and LCP can obtain obviously short-term efficacy, while there is no significant difference between two groups in long-term results. For serious distal radius comminuted fracture which unable to plate internal fixation, external fixators is a better choice.
Primary hyperparathyroidism associated with a giant cell tumor: One case in the distal radius.
Ouzaa, M R; Bennis, A; Iken, M; Abouzzahir, A; Boussouga, M; Jaafar, A
2015-10-01
Hyperparathyroidism can present itself as brown tumors (or osteolytic expansive lesions) that usually disappear after normalization of calcium and phosphate levels. It rarely occurs simultaneously with a giant cell tumor. The authors report one case of a localized form at the distal radius in a patient being followed for primary hyperparathyroidism. The diagnostic challenges related to the clinical and radiological similarities of these two pathological entities are discussed, as they can lead to delays in therapeutic management. Copyright © 2015 Elsevier Masson SAS. All rights reserved.
International Nuclear Information System (INIS)
Liu, Wanhai; Yu, Changping; Li, Xinliang
2014-01-01
Nonlinear saturation amplitudes (NSAs) of the first two harmonics in classical Rayleigh-Taylor instability (RTI) in cylindrical geometry for arbitrary Atwood numbers have been analytically investigated considering nonlinear corrections up to the fourth-order. The NSA of the fundamental mode is defined as the linear (purely exponential) growth amplitude of the fundamental mode at the saturation time when the growth of the fundamental mode (first harmonic) is reduced by 10% in comparison to its corresponding linear growth, and the NSA of the second harmonic can be obtained in the same way. The analytic results indicate that the effects of the initial radius of the interface (r 0 ) and the Atwood number (A) play an important role in the NSAs of the first two harmonics in cylindrical RTI. On the one hand, the NSA of the fundamental mode first increases slightly and then decreases quickly with increasing A. For given A, the smaller the r 0 /λ (with λ perturbation wavelength) is, the larger the NSA of the fundamental mode is. When r 0 /λ is large enough (r 0 ≫λ), the NSA of the fundamental mode is reduced to the prediction of previous literatures within the framework of third-order perturbation theory [J. W. Jacobs and I. Catton, J. Fluid Mech. 187, 329 (1988); S. W. Haan, Phys. Fluids B 3, 2349 (1991)]. On the other hand, the NSA of the second harmonic first decreases quickly with increasing A, reaching a minimum, and then increases slowly. Furthermore, the r 0 can reduce the NSA of the second harmonic for arbitrary A at r 0 ≲2λ while increase it for A ≲ 0.6 at r 0 ≳2λ. Thus, it should be included in applications where the NSA has a role, such as inertial confinement fusion ignition target design
A method to provide rapid in situ determination of tip radius in dynamic atomic force microscopy
International Nuclear Information System (INIS)
Santos, Sergio; Guang Li; Souier, Tewfik; Gadelrab, Karim; Chiesa, Matteo; Thomson, Neil H.
2012-01-01
We provide a method to characterize the tip radius of an atomic force microscopy in situ by monitoring the dynamics of the cantilever in ambient conditions. The key concept is that the value of free amplitude for which transitions from the attractive to repulsive force regimes are observed, strongly depends on the curvature of the tip. In practice, the smaller the value of free amplitude required to observe a transition, the sharper the tip. This general behavior is remarkably independent of the properties of the sample and cantilever characteristics and shows the strong dependence of the transitions on the tip radius. The main advantage of this method is rapid in situ characterization. Rapid in situ characterization enables one to continuously monitor the tip size during experiments. Further, we show how to reproducibly shape the tip from a given initial size to any chosen larger size. This approach combined with the in situ tip size monitoring enables quantitative comparison of materials measurements between samples. These methods are set to allow quantitative data acquisition and make direct data comparison readily available in the community.
Investigating the Effect of Approach Angle and Nose Radius on Surface Quality of Inconel 718
Kumar, Sunil; Singh, Dilbag; Kalsi, Nirmal S.
2017-11-01
This experimental work presents a surface quality evaluation of a Nickel-Cr-Fe based Inconel 718 superalloy, which has many applications in the aero engine and turbine components. However, during machining, the early wear of tool leads to decrease in surface quality. The coating on cutting tool plays a significant role in increasing the wear resistance and life of the tool. In this work, the aim is to study the surface quality of Inconel 718 with TiAlN-coated carbide tools. Influence of various geometrical parameters (tool nose radius, approach angle) and machining variables (cutting velocity, feed rate) on the quality of machined surface (surface roughness) was determined by using central composite design (CCD) matrix. The mathematical model of the same was developed. Analysis of variance was used to find the significance of the parameters. Results showed that the tool nose radius and feed were the main active factors. The present experiment accomplished that TiAlN-coated carbide inserts result in better surface quality as compared with uncoated carbide inserts.
Effect of minimal length uncertainty on the mass-radius relation of white dwarfs
Mathew, Arun; Nandy, Malay K.
2018-06-01
Generalized uncertainty relation that carries the imprint of quantum gravity introduces a minimal length scale into the description of space-time. It effectively changes the invariant measure of the phase space through a factor (1 + βp2) - 3 so that the equation of state for an electron gas undergoes a significant modification from the ideal case. It has been shown in the literature (Rashidi 2016) that the ideal Chandrasekhar limit ceases to exist when the modified equation of state due to the generalized uncertainty is taken into account. To assess the situation in a more complete fashion, we analyze in detail the mass-radius relation of Newtonian white dwarfs whose hydrostatic equilibria are governed by the equation of state of the degenerate relativistic electron gas subjected to the generalized uncertainty principle. As the constraint of minimal length imposes a severe restriction on the availability of high momentum states, it is speculated that the central Fermi momentum cannot have values arbitrarily higher than pmax ∼β - 1 / 2. When this restriction is imposed, it is found that the system approaches limiting mass values higher than the Chandrasekhar mass upon decreasing the parameter β to a value given by a legitimate upper bound. Instead, when the more realistic restriction due to inverse β-decay is considered, it is found that the mass and radius approach the values 1.4518 M⊙ and 601.18 km near the legitimate upper bound for the parameter β.
M DWARF LUMINOSITY, RADIUS, AND α-ENRICHMENT FROM I-BAND SPECTRAL FEATURES
Energy Technology Data Exchange (ETDEWEB)
Terrien, Ryan C.; Mahadevan, Suvrath; Bender, Chad F.; Deshpande, Rohit; Robertson, Paul, E-mail: rct151@psu.edu [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)
2015-03-20
Despite the ubiquity of M dwarfs and their growing importance to studies of exoplanets, Galactic evolution, and stellar structure, methods for precisely measuring their fundamental stellar properties remain elusive. Existing techniques for measuring M dwarf luminosity, mass, radius, or composition are calibrated over a limited range of stellar parameters or require expensive observations. We find a strong correlation between the K{sub S}-band luminosity (M{sub K}), the observed strength of the I-band sodium doublet absorption feature, and [Fe/H] in M dwarfs without strong Hα emission. We show that the strength of this feature, coupled with [Fe/H] and spectral type, can be used to derive M dwarf M{sub K} and radius without requiring parallax. Additionally, we find promising evidence that the strengths of the I-band sodium doublet and the nearby I-band calcium triplet may jointly indicate α-element enrichment. The use of these I-band features requires only moderate-resolution near-infrared spectroscopy to provide valuable information about the potential habitability of exoplanets around M dwarfs, and surface gravity and distance for M dwarfs throughout the Galaxy. This technique has immediate applicability for both target selection and candidate planet–host system characterization for exoplanet missions such as TESS and K2.
Investigations on the Effect of Radius Rotor in Combined Darrieus-Savonius Wind Turbine
Directory of Open Access Journals (Sweden)
Kaprawi Sahim
2018-01-01
Full Text Available Renewable sources of energy, abundant in availability, are needed to be exploited with adaptable technology. For wind energy, the wind turbine is very well adapted to generate electricity. Among the different typologies, small scale Vertical Axis Wind Turbines (VAWT present the greatest potential for off-grid power generation at low wind speeds. The combined Darrieus-Savonius wind turbine is intended to enhance the performance of the Darrieus rotor in low speed. In combined turbine, the Savonius buckets are always attached at the rotor shaft and the Darrieus blades are installed far from the shaft which have arm attaching to the shaft. A simple combined turbine offers two rotors on the same shaft. The combined turbine that consists of two Darrieus and Savonius blades was tested in wind tunnel test section with constant wind velocity and its performance was assessed in terms of power and torque coefficients. The study gives the effect of the radius ratio between Savonius and Darrieus rotor on the performance of the turbine. The results show that there is a significant influence on the turbine performance if the radius ratio was changed.
Measurement of humerus and radius bone mineral content in the term and preterm infant
International Nuclear Information System (INIS)
Vyhmeister, N.R.; Linkhart, T.A.
1988-01-01
We compared two anatomic sites for single-photon absorptiometric measurement of bone mineral content (BMC) in term and preterm infants. The distal one third of the radius and the midportion of the humerus were evaluated for measurements of BMC with an unmodified, commercially available bone densitometer. We assessed reproducibility of BMC and bone width (BW) measurements and defined normal at-birth ranges of BMC, BW, and BMC/BW ratio for infants with gestational ages of 24 to 42 weeks. Humerus BMC correlated with gestational age, birth weight, and BW of patients and did not differ from humerus BMC values determined over the same range of gestational ages at another center. Representative serial measurements of two very low birth weight (VLBW) infants are presented to demonstrate the feasibility of using humerus BMC in longitudinal studies to assess changes in bone mineralization. We conclude that bone densitometer measurements of mid-humerus BMC can be successfully performed and are preferable to similar measurements of the radius for VLBW infants. Normal humerus BMC values were defined for use in diagnosis and evaluation of the efficacy of treatment in VLBW infants who are at high risk of developing osteopenia of prematurity
Neutron-Star Radius from a Population of Binary Neutron Star Mergers.
Bose, Sukanta; Chakravarti, Kabir; Rezzolla, Luciano; Sathyaprakash, B S; Takami, Kentaro
2018-01-19
We show how gravitational-wave observations with advanced detectors of tens to several tens of neutron-star binaries can measure the neutron-star radius with an accuracy of several to a few percent, for mass and spatial distributions that are realistic, and with none of the sources located within 100 Mpc. We achieve such an accuracy by combining measurements of the total mass from the inspiral phase with those of the compactness from the postmerger oscillation frequencies. For estimating the measurement errors of these frequencies, we utilize analytical fits to postmerger numerical relativity waveforms in the time domain, obtained here for the first time, for four nuclear-physics equations of state and a couple of values for the mass. We further exploit quasiuniversal relations to derive errors in compactness from those frequencies. Measuring the average radius to well within 10% is possible for a sample of 100 binaries distributed uniformly in volume between 100 and 300 Mpc, so long as the equation of state is not too soft or the binaries are not too heavy. We also give error estimates for the Einstein Telescope.
Energy Technology Data Exchange (ETDEWEB)
Hagino, Hiroshi
1989-01-01
Using 125-I single photon absorptiometry, bone mineral measurements were performed on 206 healthy Japanese children (2 to 19 years of age). Bone mineral content (BMC), bone width (BW) and BMC/BW values were determined for the radius at distal 1/6 site (metaphysis) and distal 1/3 site (diaphysis). BMC/BW values at both sites correlated well with body height and weight. Bone mass in the diaphysis (distal 1/3 site) increased linearly during the 2-19 years of skeletal growth, but bone mass in the metaphysis (1/6 site) increased steeply during the pubertal period. In children receiving glucocorticoid therapy, bone mass was reduced in proportion to the duration of drug administration. In children under anticonvulsant therapy, the yearly increse in bone mass was significantly low especially in those patients with poor physical activity levels. Bone mineral decrease in the radius occurred in the children with hypopituitalism, hypothyroidism (cretinism), hyperthyroidism and Turner's syndrome.
Nodule detection in digital chest radiography: Introduction to the radius chest trial
International Nuclear Information System (INIS)
Baath, M.; Haakansson, M.; Boerjesson, S.; Kheddache, S.; Grahn, A.; Ruschin, M.; Tingberg, A.; Mattsson, S.; Maansson, L. G.
2005-01-01
Most digital radiographic systems of today have wide latitude and are hence able to provide images with a small constraint on dose level. This opens up for an unprejudiced dose optimisation. However, in order to succeed in the optimisation task, good knowledge of the imaging and detection processes is needed. As a part of the European-wide research project 'unification of physical and clinical requirements for medical X-ray imaging - governed by the Radiological Imaging Unification Strategies (RADIUS) Group - a major image quality trial was conducted by members of the group. The RADIUS chest trial was focused on the detection of lung nodules in digital chest radiography with the aims of determining to what extent (1) the detection of a nodule is dependent on its location, (2) the system noise disturbs the detection of lung nodules, (3) the anatomical noise disturbs the detection of lung nodules and (4) the image background and anatomical background act as pure noise for the detection of lung nodules. The purpose of the present paper is to give an introduction to the trial and describe the framework and set-up of the investigation. (authors)
Treatment of unstable distal radius fractures with Ilizarov circular, nonbridging external fixator.
Tyllianakis, Minos; Mylonas, Spyros; Saridis, Alkis; Kallivokas, Alkiviadis; Kouzelis, Antonis; Megas, Panagiotis
2010-03-01
Unstable distal radius fractures remain a challenge for the treating orthopaedic surgeon. We present a retrospective follow-up study (mean follow-up 12.5 months) of 20 patients with 21 unstable distal radius fractures that were reduced in a closed manner and stabilized with a nonbridging Ilizarov external fixator. Subsequent insertion of olive wires for interfragmentary compression was performed in cases with intra-articular fractures. According to the overall evaluation proposed by Gartland and Werley scoring system 12 wrists were classified as excellent, 6 as good, 2 as fair and 1 as poor. Grade II pin-tract infection in distal fracture fragment was detected in 3 wires from a total of 78 (3.8%) and in 4 half pins out of a total of 9 (44.4%). Pronation was the most frequently impaired movement. This was restricted in 4 patients (19%) in whom a radioulnar transfixing wire was applied. Symptoms of irritation of superficial sensory branch of the radial nerve occurred in 3 patients with an olive wire applied in a closed manner in the distal fragment. Ilizarov method yields functional results comparable to that of other methods whilst it avoids wrist immobilization, open reduction and reoperation for implant removal. The method is associated with a low rate of major complication and satisfactory functional outcome. Copyright 2009 Elsevier Ltd. All rights reserved.
Analyzing the effect of tool edge radius on cutting temperature in micro-milling process
Liang, Y. C.; Yang, K.; Zheng, K. N.; Bai, Q. S.; Chen, W. Q.; Sun, G. Y.
2010-10-01
Cutting heat is one of the important physical subjects in the cutting process. Cutting heat together with cutting temperature produced by the cutting process will directly have effects on the tool wear and the life as well as on the workpiece processing precision and surface quality. The feature size of the workpiece is usually several microns. Thus, the tiny changes of cutting temperature will affect the workpiece on the surface quality and accuracy. Therefore, cutting heat and temperature generated in micro-milling will have significantly different effect than the one in the traditional tools cutting. In this paper, a two-dimensional coupled thermal-mechanical finite element model is adopted to determine thermal fields and cutting temperature during the Micro-milling process, by using software Deform-2D. The effect of tool edge radius on effective stress, effective strain, velocity field and cutting temperature distribution in micro-milling of aluminum alloy Al2024-T6 were investigated and analyzed. Also, the transient cutting temperature distribution was simulated dynamically. The simulation results show that the cutting temperature in Micro-milling is lower than those occurring in conventional milling processes due to the small loads and low cutting velocity. With increase of tool edge radius, the maximum temperature region gradually occurs on the contact region between finished surfaced and flank face of micro-cutter, instead of the rake face or the corner of micro-cutter. And this phenomenon shows an obvious size effect.
WHAT IS THE BEST RADIOGRAPHIC VIEW FOR "DIE PUNCH" DISTAL RADIUS FRACTURES? A CADAVER MODEL STUDY.
Falcochio, Diego Figueira; Crepaldi, Bruno Eiras; Trindade, Christiano Augusto; da Costa, Antonio Carlos; Chakkour, Ivan
2012-01-01
the aim of this study is try to show the best view for distal radius fractures so called die-punch fractures. There has been used a human cadaver radius bone from the Salvador Arena Tissue Bank. This bone was cleaned up after removing the soft tissues and osteotomies created displaced lunate fossa fractures of 0, 1, 2, 3 and 5 mm. We have fixed this fragment with adhesive tape. Then the joint deviation were significantly increased with step-offs of 1 mm. Radiographs were then taken into 5 different positions: postero-anterior view, lateral view, oblique views and tangencial view for each of the deviations. The resulting lunate fossa depression in each X-ray film was analyzed by the AutoCAD 2010® software. The tangencial view was the best one to see the 1mm and 3mm bone degrees and the second one view to see the 2mm and 5 mm degrees. The pronated oblique view was the best to see the 2mm degrees and the oblique supinated view wasn't able to see the degrees between 1 and 2mm. The tangencial view was the best one to see the 1mm and 3mm bone degrees and the second one view to see the 2mm and 5 mm degrees.
Stewart, Suzanne; Richardson, Dean; Boston, Ray; Schaer, Thomas P
2015-11-01
To determine (1) survival to discharge of horses with radial fractures (excluding osteochondral fragmentation of the distal aspect of the radius and stress fractures); and (2) risk factors affecting survival to hospital discharge in conservative and surgically managed fractures. Case series. Horses (n = 54). Medical records (1990-June 2012) and radiographs of horses admitted with radial fracture were reviewed. Horses with osteochondral fragmentation of the distal aspect of the radius or stress fractures were excluded. Evaluated risk factors were age, fracture configuration, surgical repair method, surgical duration, hospitalization time, implant failure rate, and surgical site infection (SSI) rate. Of 54 horses, overall survival to discharge was 50%. Thirteen (24%) were euthanatized on admission because of (1) fracture severity; (2) presence of an open fracture; or (3) financial constraints. Fourteen (26%) horses with minimally displaced incomplete fractures were conservatively managed and 12 (86%) survived to discharge. Twenty-seven (50%) horses had surgical treatment by open reduction and internal fixation (ORIF) and 15 (56%) survived to hospital discharge. Open fractures were significantly more likely to develop SSI (P = .008), which also resulted in a 17-fold increase in implant failure (P horses with an open fracture did not survive to discharge. Outcome was also adversely affected by age (P 168 minutes (P fractures is good. Young horses have a good prognosis survival to discharge for ORIF, whereas ORIF in adult horses has a poor prognosis and SSI strongly correlates with catastrophic implant failure. © Copyright 2015 by The American College of Veterinary Surgeons.
A SCALING RELATION BETWEEN MEGAMASER DISK RADIUS AND BLACK HOLE MASS IN ACTIVE GALACTIC NUCLEI
International Nuclear Information System (INIS)
Wardle, Mark; Yusef-Zadeh, Farhad
2012-01-01
Several thin, Keplerian, sub-parsec megamaser disks have been discovered in the nuclei of active galaxies and used to precisely determine the mass of their host black holes. We show that there is an empirical linear correlation between the disk radius and the black hole mass. We demonstrate that such disks are naturally formed by the partial capture of molecular clouds passing through the galactic nucleus and temporarily engulfing the central supermassive black hole. Imperfect cancellation of the angular momenta of the cloud material colliding after passing on opposite sides of the hole leads to the formation of a compact disk. The radial extent of the disk is determined by the efficiency of this process and the Bondi-Hoyle capture radius of the black hole, and naturally produces the empirical linear correlation of the radial extent of the maser distribution with black hole mass. The disk has sufficient column density to allow X-ray irradiation from the central source to generate physical and chemical conditions conducive to the formation of 22 GHz H 2 O masers. For initial cloud column densities ∼ 23.5 cm –2 the disk is non-self-gravitating, consistent with the ordered kinematics of the edge-on megamaser disks; for higher cloud columns the disk would fragment and produce a compact stellar disk similar to that observed around Sgr A* at the galactic center.
Examination of Skill Acquisition and Grader Bias in a Distal Radius Fracture Fixation Model.
Putnam, Matthew D; Adams, Julie E; Lender, Paul; Van Heest, Ann E; Shanedling, Janet R; Nuckley, David J; Bechtold, Joan E
2018-03-01
Primary: Assess the ability of faculty graders to predict the objectively measured strength of distal radius fracture fixation. Secondary: Compare resident skill variation and retention related to other knowable training data. Residents were allowed 60 minutes to stabilize a standardized distal radius fracture using an assigned fixed-angle volar plate. Faculty observed and subjectively graded the residents without providing real-time feedback. Objective biomechanical evaluation (construct strength and stiffness) was compared to subjective grades. Resident-specific characteristics (sex, PGY, and ACGME case log) were also used to compare the objective data. A simulated operating room in our laboratory. Post-graduate year 2, 3, 4, and 5 orthopedic residents. Primary: Faculty were not successful at predicting objectively measured fixation, and their subjective scoring suggests confirmation bias as PGY increased. Secondary: Resident year-in-training alone did not predict objective measures (p = 0.53), but was predictive of subjective scores (p external faculty unfamiliar with tested residents, might alter these results. Copyright © 2018 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.
Weaver, Arthur; Troum, Orrin; Hooper, Michele; Koenig, Andrew S; Chaudhari, Sandeep; Feng, Jingyuan; Wenkert, Deborah
2013-08-01
To determine whether disease activity and disability independently correlate with serious infection event (SIE) risk in a large rheumatoid arthritis (RA) cohort. The associations between SIE and Clinical Disease Activity Index (CDAI) and Health Assessment Questionnaire-Disability Index (HAQ-DI) in the Rheumatoid Arthritis Disease-Modifying Antirheumatic Drug Intervention and Utilization Study (RADIUS 1) cohort were evaluated using the Andersen-Gill model (a proportional HR model allowing > 1 event per patient). Of 4084 patients with 347 SIE, 271 patients experienced ≥ 1 SIE. A 5-unit CDAI increase and 0.4-unit HAQ-DI increase corresponded to an increase in SIE risk with and without covariate adjustments. A 5-unit CDAI increase corresponded with a 7.7% increased SIE risk (adjusted HR 1.077, 95% CI 1.044-1.112, p < 0.0001) and a 0.4-unit HAQ-DI increase with a 30.1% increased risk (adjusted HR 1.301, 95% CI 1.225-1.381, p < 0.0001). Categorical analysis showed that more severe RA activity (even after controlling for disability) and disability were associated with an increased SIE risk. Increased RA disease activity and disability were each associated with a significantly increased SIE risk in the RADIUS 1 cohort, which could not be completely accounted for by disability.
Arthroscopic knotless anchor repair of triangular fibrocartilage in distal radius fracture.
García-Ruano, Á A; Najarro-Cid, F; Jiménez-Martín, A; Gómez de los Infantes-Troncoso, J G; Sicre-González, M
2015-01-01
Lesions of triangular fibrocartilage (TFC) are associated with distal radioulnar joint instability. Arthroscopic treatment of these lesions improves functional outcome of affected patients. The aim of the present work is to evaluate functional and occupational outcome of TCF repair using an arthroscopic knotless anchor device in patients with associated distal radius fracture. An observational, descriptive study was carried out between November 2011 and January 2014 including 21 patients with distal radius fracture and Palmer 1B lesions of TCF (Atzei class 2 and 3) that were treated by arthroscopic knotless anchor (PopLok® 2,8mm, ConMed, USA). Mean follow-up was 18 months. Functional (Mayo Wrist Score) and occupational outcome results were analyzed. Mean age of the group was 43.0±8.8 years, with 19% of the patients being female. There was an associated scapholunate lesion in 5 cases. Functional results reached a mean of 83.4±16.1 points onMayo Wrist Score. Mean sick-leave time was 153.16±48.5 days. Complete occupational reintegration was reached in 89.5% of cases. There were no postoperative complications. Arthroscopic knotless anchor repair of 1B TFC tears is a minimally invasive method of treatment that improves tension of fixation, avoiding subsequent loosen, in our experience, with few complications and good functional and occupational results. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.
Aerodynamic performance investigation on waverider with variable blunt radius in hypersonic flows
Li, Shibin; Wang, Zhenguo; Huang, Wei; Xu, Shenren; Yan, Li
2017-08-01
Waverider is an important candidate for the design of hypersonic vehicles. However, the ideal waverider cannot be manufactured because of its sharp leading edge, so the leading edge should be blunted. In the paper, the HMB solver and laminar flow model have been utilized to obtain the flow field properties around the blunt waverider with the freestream Mach number being 8.0, and several novel strategies have been suggested to improve the aerodynamic performance of blunt waverider. The numerical method has been validated against experimental data, and the Stanton number(St) of the predicted result has been analyzed. The obtained results show good agreement with the experimental data. Stmax decreases by 58% and L/D decreases by 8.2% when the blunt radius increases from 0.0002 m to 0.001 m. ;Variable blunt waverider; is a good compromise for aerodynamic performance and thermal insulation. The aero-heating characteristics are very sensitive to Rmax. The position of the smallest blunt radius has a great effect on the aerodynamic performance. In addition, the type of blunt leading edge has a great effect on the aero-heating characteristics when Rmax is fixed. Therefore, out of several designs, Type 4is the best way to achieve the good overall performance. The ;Variable blunt waverider; not only improves the aerodynamic performance, but also makes the aero-heating become evenly-distributed, leading to better aero-heating characteristics.
Directory of Open Access Journals (Sweden)
Saraf S
2005-01-01
Full Text Available Background: The bulk of literature on the subject focuses on the resection of the tumor followed by reconstruction using autologous fibula, however, papers analyzing the failures of this procedure are scanty. The aim is to analyze the various factors responsible for the failures. Methods: Study included 42 patients of aggressive GCT of distal radius, resected and reconstructed using nonvascularised autologous fibula. Host graft junction was fixed using screws (6, intramedullary nail (21 and plate (15. The minimum follow-up was 2 years or till a complication occurred requiring second surgery. Result: The major complications were recurrence in 6 cases (spillage of tumor tissue in 3, poor biopsy site 2, recurrence along the nail tract one case; failure of host graft union in 8 cases due to inadequate contact at host graft junction, poor implant selection, inadequate immobilization and infection; significant instability at wrist in 6 cases due to poor stabilization at carpo fibular junction in addition to inherent instability due to poor congruity between fibulocarpal articulations. Conclusion: Reconstruction of distal end of radius using auto fibula has much higher complication rates than usually believed. A meticulous planning and its execution is must to minimize the problems. Use of dynamic plate for host graft junction and fixation of fibular head to adjacent ulna/carpal bones improves the results.
Measurement Of Neutron Radius In Lead By Parity Violating Scattering Flash ADC DAQ
Energy Technology Data Exchange (ETDEWEB)
Ahmed, Zafar [Christopher Newport Univ., Newport News, VA (United States)
2012-06-01
This dissertation reports the experiment PREx, a parity violation experiment which is designed to measure the neutron radius in ^{208}Pb. PREx is performed in hall A of Thomas Jefferson National Accelerator Facility from March 19th to June 21st. Longitudionally polarized electrons at energy 1 GeV scattered at and angle of θ_{lab }= 5.8 ° from the Lead target. Beam corrected pairty violaing counting rate asymmetry is (A_{corr}= 594 ± 50(stat) ± 9(syst))ppb at Q^{2} = 0.009068GeV ^{2}. This dissertation also presents the details of Flash ADC Data Acquisition(FADC DAQ) system for Moller polarimetry in Hall A of Thomas Jefferson National Accelerator Facility. The Moller polarimeter measures the beam polarization to high precision to meet the specification of the PREx(Lead radius experiment). The FADC DAQ is part of the upgrade of Moller polarimetery to reduce the systematic error for PREx. The hardware setup and the results of the FADC DAQ analysis are presented
Read, Tyson J G; Segre, Paolo S; Middleton, Kevin M; Altshuler, Douglas L
2016-03-01
Turning in flight requires reorientation of force, which birds, bats and insects accomplish either by shifting body position and total force in concert or by using left-right asymmetries in wingbeat kinematics. Although both mechanisms have been observed in multiple species, it is currently unknown how each is used to control changes in trajectory. We addressed this problem by measuring body and wingbeat kinematics as hummingbirds tracked a revolving feeder, and estimating aerodynamic forces using a quasi-steady model. During arcing turns, hummingbirds symmetrically banked the stroke plane of both wings, and the body, into turns, supporting a body-dependent mechanism. However, several wingbeat asymmetries were present during turning, including a higher and flatter outer wingtip path and a lower more deviated inner wingtip path. A quasi-steady analysis of arcing turns performed with different trajectories revealed that changes in radius were associated with asymmetrical kinematics and forces, and changes in velocity were associated with symmetrical kinematics and forces. Collectively, our results indicate that both body-dependent and -independent force orientation mechanisms are available to hummingbirds, and that these kinematic strategies are used to meet the separate aerodynamic challenges posed by changes in velocity and turning radius. © 2016 The Author(s).
Study on the Optimal Equivalent Radius in Calculating the Heat Dissipation of Surrounding Rock
Directory of Open Access Journals (Sweden)
H. T. Song
2015-11-01
Full Text Available The heat dissipation of surrounding rock of a non-circular roadway is computed using an equivalent circular roadway approach under three circumstances when the area, perimeter, or hydraulic diameter of the circular roadway is equal to the non-circular roadway to obtain the optimal equivalent radius. The differential equations of heat conduction for unstable surrounding rock are established in cylindrical and rectangular coordinate systems using dimensionless analysis method. The calculation formulas of heat dissipation capacity and heat transfer resistance are derived from differential equations. Based on the method of equivalent radius, the similarities and differences between non-circular and circular roadways in calculating the heat dissipation of surrounding rock are discussed. Using the finite volume method, the calculation models for non-circular and circular roadways in the heat dissipation of surrounding rock are also established, among the non-circular roadways including three circumstances, namely, trapezoid, rectangle, and arch. The relation errors of heat dissipation of the surrounding rock of the three equivalent circular roadway methods are investigated for the three non-circular roadways. Results show that the calculation approach with equal perimeters is the best for the heat dissipation of surrounding rock of non-circular roadways.
M DWARF LUMINOSITY, RADIUS, AND α-ENRICHMENT FROM I-BAND SPECTRAL FEATURES
International Nuclear Information System (INIS)
Terrien, Ryan C.; Mahadevan, Suvrath; Bender, Chad F.; Deshpande, Rohit; Robertson, Paul
2015-01-01
Despite the ubiquity of M dwarfs and their growing importance to studies of exoplanets, Galactic evolution, and stellar structure, methods for precisely measuring their fundamental stellar properties remain elusive. Existing techniques for measuring M dwarf luminosity, mass, radius, or composition are calibrated over a limited range of stellar parameters or require expensive observations. We find a strong correlation between the K S -band luminosity (M K ), the observed strength of the I-band sodium doublet absorption feature, and [Fe/H] in M dwarfs without strong Hα emission. We show that the strength of this feature, coupled with [Fe/H] and spectral type, can be used to derive M dwarf M K and radius without requiring parallax. Additionally, we find promising evidence that the strengths of the I-band sodium doublet and the nearby I-band calcium triplet may jointly indicate α-element enrichment. The use of these I-band features requires only moderate-resolution near-infrared spectroscopy to provide valuable information about the potential habitability of exoplanets around M dwarfs, and surface gravity and distance for M dwarfs throughout the Galaxy. This technique has immediate applicability for both target selection and candidate planet–host system characterization for exoplanet missions such as TESS and K2
International Nuclear Information System (INIS)
Sonier, J.E.; Kiefl, R.F.; Brewer, J.H.; Chakhalian, J.; Dunsiger, S.R.; MacFarlane, W.A.; Miller, R.I.; Wong, A.; Luke, G.M.; Brill, J.W.
1997-01-01
Muon-spin rotation spectroscopy (μSR) has been used to measure the internal magnetic field distribution in NbSe 2 for H c1 c2 . The deduced profiles of the supercurrent density J s indicate that the vortex-core radius ρ 0 in the bulk decreases sharply with increasing magnetic field. This effect, which is attributed to increased vortex-vortex interactions, does not agree with the dirty-limit microscopic theory. A simple phenomenological equation in which ρ 0 depends on the intervortex spacing is used to model this behavior. In addition, we find for the first time that the in-plane magnetic penetration depth λ ab increases linearly with H in the vortex state of a conventional superconductor. copyright 1997 The American Physical Society
Directory of Open Access Journals (Sweden)
Asit Kumar Parida
2017-04-01
Full Text Available In the present work, the variation of nose radius on forces, cutting temperature, stress, has been studied using finite element modeling in hot turning operation of Inconel 718. Three values of nose radius were taken (0.4, 0.8 and 1.2 mm. Cutting force, thrust force, stress, and cutting temperature have been predicted using commercial DEFORM™ software at different cutting tool nose radius in both room and heated conditions. With the increase of tool nose radius in both room and elevated machining conditions the cutting force and thrust force increased. The cutting temperature, chip thickness and chip tool contact length also have been studied. In order to validate the numerical results an experimental analysis has been performed and good agreement between them has been observed
Kasapinova, K; Kamiloski, V
2016-06-01
Our purpose was to determine the correlation of initial radiographic parameters of a distal radius fracture with an injury of the triangular fibrocartilage complex. In a prospective study, 85 patients with surgically treated distal radius fractures were included. Wrist arthroscopy was used to identify and classify triangular fibrocartilage complex lesions. The initial radial length and angulation, dorsal angulation, ulnar variance and distal radioulnar distance were measured. Wrist arthroscopy identified a triangular fibrocartilage complex lesion in 45 patients. Statistical analysis did not identify a correlation with any single radiographic parameter of the distal radius fractures with the associated triangular fibrocartilage complex injuries. The initial radiograph of a distal radius fracture does not predict a triangular fibrocartilage complex injury. III. © The Author(s) 2016.
Teaching the Basics: Development and Validation of a Distal Radius Reduction and Casting Model.
Seeley, Mark A; Fabricant, Peter D; Lawrence, J Todd R
2017-09-01
Approximately one-third of reduced pediatric distal radius fractures redisplace, resulting in further treatment. Two major modifiable risk factors for loss of reduction are reduction adequacy and cast quality. Closed reduction and immobilization of distal radius fractures is an Accreditation Council for Graduate Medical Education residency milestone. Teaching and assessing competency could be improved with a life-like simulation training tool. Our goal was to develop and validate a realistic distal radius fracture reduction and casting simulator as determined by (1) a questionnaire regarding the "realism" of the model and (2) the quantitative assessments of reduction time, residual angulation, and displacement. A distal radius fracture model was created with radiopaque bony segments and articulating elbows and shoulders. Simulated periosteum and internal deforming forces required proper reduction and casting techniques to achieve and maintain reduction. The forces required were estimated through an iterative process through feedback from experienced clinicians. Embedded monofilaments allowed for quantitative assessment of residual displacement and angulation through the use of fluoroscopy. Subjects were asked to perform closed reduction and apply a long arm fiberglass cast. Primary performance variables assessed included reduction time, residual angulation, and displacement. Secondary performance variables consisted of number of fluoroscopic images, casting time, and cast index (defined as the ratio of the internal width of the forearm cast in the sagittal plane to the internal width in the coronal plane at the fracture site). Subject grading was performed by two blinded reviewers. Interrater reliability was nearly perfect across all measurements (intraclass correlation coefficient range, 0.94-0.99), thus disagreements in measurements were handled by averaging the assessed values. After completion the participants answered a Likert-based questionnaire regarding the
Ram Kumar Deo; Robert E. Froese; Michael J. Falkowski; Andrew T. Hudak
2016-01-01
The conventional approach to LiDAR-based forest inventory modeling depends on field sample data from fixed-radius plots (FRP). Because FRP sampling is cost intensive, combining variable-radius plot (VRP) sampling and LiDAR data has the potential to improve inventory efficiency. The overarching goal of this study was to evaluate the integration of LiDAR and VRP data....
Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC
Energy Technology Data Exchange (ETDEWEB)
Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Wanotayaroj, Chaowaroj [Center for High Energy Physics, University of Oregon,1371 E. 13th Ave, Eugene, OR 97403 (United States)
2015-02-12
Jets with a large radius R≳1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large-R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale r
Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC
International Nuclear Information System (INIS)
Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj
2015-01-01
Jets with a large radius R≳1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large-R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale r
Theory of fast (nonadiabatic) nuclear rotation
International Nuclear Information System (INIS)
Nosov, V.G.; Kamchatnov, A.M.
1977-01-01
The theory of backbending is developed taking into accout the increasing role of nonadiabatic effects, which are concerned with quantum number K violation. Above the transition point, rotation quantum number j (>=) jsub(c) (second-kind transition point), all possible values of the quantity K in the interval -J ( Jsub(c) are obtained. The radius of global nucleon mass distribution in the nucleus is defined from the analysis of the experimental moments of inertia in n-phase. It is in agreement with the radius of distribution of protons alone obtained from electron scattering on nuclei. Assuming the simplest singularity of parametric derivative of the Hamiltonian of the system the general theory of non-temperature (ground state)second-kind phase transitions is developed
Jara, Pascual; Torrecillas, Blas
1988-01-01
The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.
DEFF Research Database (Denmark)
Hendricks, Vincent F.
Game Theory is a collection of short interviews based on 5 questions presented to some of the most influential and prominent scholars in game theory. We hear their views on game theory, its aim, scope, use, the future direction of game theory and how their work fits in these respects....
Crockett, K; Arnold, C M; Farthing, J P; Chilibeck, P D; Johnston, J D; Bath, B; Baxter-Jones, A D G; Kontulainen, S A
2015-10-01
Distal radius (wrist) fracture (DRF) in women over age 50 years is an early sign of bone fragility. Women with a recent DRF compared to women without DRF demonstrated lower bone strength, muscle density, and strength, but no difference in dual-energy x-ray absorptiometry (DXA) measures, suggesting DXA alone may not be a sufficient predictor for DRF risk. The objective of this study was to investigate differences in bone and muscle properties between women with and without a recent DRF. One hundred sixty-six postmenopausal women (50-78 years) were recruited. Participants were excluded if they had taken bone-altering medications in the past 6 months or had medical conditions that severely affected daily living or the upper extremity. Seventy-seven age-matched women with a fracture in the past 6-24 months (Fx, n = 32) and without fracture (NFx, n = 45) were measured for bone and muscle properties using the nondominant (NFx) or non-fractured limb (Fx). Peripheral quantitative computed tomography (pQCT) was used to estimate bone strength in compression (BSIc) at the distal radius and tibia, bone strength in torsion (SSIp) at the shaft sites, muscle density, and area at the forearm and lower leg. Areal bone mineral density at the ultradistal forearm, spine, and femoral neck was measured by DXA. Grip strength and the 30-s chair stand test were used as estimates of upper and lower extremity muscle strength. Limb-specific between-group differences were compared using multivariate analysis of variance (MANOVA). There was a significant group difference (p lower leg, with the Fx group demonstrating 16 and 19% lower BSIc, 3 and 6% lower muscle density, and 20 and 21% lower muscle strength at the upper and lower extremities, respectively. There were no differences between groups for DXA measures. Women with recent DRF had lower pQCT-derived estimated bone strength at the distal radius and tibia and lower muscle density and strength at both extremities.
THE MASS OF KOI-94d AND A RELATION FOR PLANET RADIUS, MASS, AND INCIDENT FLUX
International Nuclear Information System (INIS)
Weiss, Lauren M.; Marcy, Geoffrey W.; Isaacson, Howard; Kolbl, Rea; Rowe, Jason F.; Howell, Steve B.; Howard, Andrew W.; Fortney, Jonathan J.; Miller, Neil; Demory, Brice-Olivier; Seager, Sara; Fischer, Debra A.; Adams, Elisabeth R.; Dupree, Andrea K.; Johnson, John Asher; Horch, Elliott P.; Everett, Mark E.; Fabrycky, Daniel C.
2013-01-01
We measure the mass of a modestly irradiated giant planet, KOI-94d. We wish to determine whether this planet, which is in a 22 day orbit and receives 2700 times as much incident flux as Jupiter, is as dense as Jupiter or rarefied like inflated hot Jupiters. KOI-94 also hosts at least three smaller transiting planets, all of which were detected by the Kepler mission. With 26 radial velocities of KOI-94 from the W. M. Keck Observatory and a simultaneous fit to the Kepler light curve, we measure the mass of the giant planet and determine that it is not inflated. Support for the planetary interpretation of the other three candidates comes from gravitational interactions through transit timing variations, the statistical robustness of multi-planet systems against false positives, and several lines of evidence that no other star resides within the photometric aperture. We report the properties of KOI-94b (M P = 10.5 ± 4.6 M ⊕ , R P = 1.71 ± 0.16 R ⊕ , P = 3.74 days), KOI-94c (M P = 15.6 +5.7 -15.6 M ⊕ , R P = 4.32 ± 0.41 R ⊕ , P = 10.4 days), KOI-94d (M P = 106 ± 11 M ⊕ , R P = 11.27 ± 1.06 R ⊕ , P = 22.3 days), and KOI-94e (M P = 35 +18 -28 M ⊕ , R P = 6.56 ± 0.62 R ⊕ , P = 54.3 days). The radial velocity analyses of KOI-94b and KOI-94e offer marginal (>2σ) mass detections, whereas the observations of KOI-94c offer only an upper limit to its mass. Using the KOI-94 system and other planets with published values for both mass and radius (138 exoplanets total, including 35 with M P ⊕ ), we establish two fundamental planes for exoplanets that relate their mass, incident flux, and radius from a few Earth masses up to 13 Jupiter masses: (R P /R ⊕ ) = 1.78(M P /M ⊕ ) 0.53 (F/erg s –1 cm –2 ) –0.03 for M P ⊕ , and R P /R ⊕ = 2.45(M P /M ⊕ ) –0.039 (F/erg s –1 cm –2 ) 0.094 for M P > 150 M ⊕ . These equations can be used to predict the radius or mass of a planet.
2010-11-29
...-AA00 Safety Zone; 1000-yard radius from position 29[deg]48.77' N 091[deg]33.02' W, Charenton Drainage.... SUMMARY: The Coast Guard is establishing a temporary safety zone extending to a 1000-yard radius from... Navigation and Drainage Canal will be closed to all marine traffic within a 1000-yard radius of position 29...
Mass corrections in string theory and lattice field theory
International Nuclear Information System (INIS)
Del Debbio, Luigi; Kerrane, Eoin; Russo, Rodolfo
2009-01-01
Kaluza-Klein (KK) compactifications of higher-dimensional Yang-Mills theories contain a number of 4-dimensional scalars corresponding to the internal components of the gauge field. While at tree level the scalar zero modes are massless, it is well known that quantum corrections make them massive. We compute these radiative corrections at 1 loop in an effective field theory framework, using the background field method and proper Schwinger-time regularization. In order to clarify the proper treatment of the sum over KK modes in the effective field theory approach, we consider the same problem in two different UV completions of Yang-Mills: string theory and lattice field theory. In both cases, when the compactification radius R is much bigger than the scale of the UV completion (R>>√(α ' ), a), we recover a mass renormalization that is independent of the UV scale and agrees with the one derived in the effective field theory approach. These results support the idea that the value of the mass corrections is, in this regime, universal for any UV completion that respects locality and gauge invariance. The string analysis suggests that this property holds also at higher loops. The lattice analysis suggests that the mass of the adjoint scalars appearing in N=2, 4 super Yang-Mills is highly suppressed, even if the lattice regularization breaks all supersymmetries explicitly. This is due to an interplay between the higher-dimensional gauge invariance and the degeneracy of bosonic and fermionic degrees of freedom.
International Nuclear Information System (INIS)
Chan Hongmo.
1987-10-01
The paper traces the development of the String Theory, and was presented at Professor Sir Rudolf Peierls' 80sup(th) Birthday Symposium. The String theory is discussed with respect to the interaction of strings, the inclusion of both gauge theory and gravitation, inconsistencies in the theory, and the role of space-time. The physical principles underlying string theory are also outlined. (U.K.)
Baryon form factors in chiral perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Kubis, B.; Meissner, U.G. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Kernphysik
2001-01-01
We analyze the electromagnetic form factors of the ground state baryon octet to fourth order in relativistic baryon chiral perturbation theory. Predictions for the {sigma}{sup -} charge radius and the {lambda}-{sigma}{sup 0} transition moment are found to be in excellent agreement with the available experimental information. Furthermore, the convergence behavior of the hyperon charge radii is shown to be more than satisfactory. (orig.)
X-ray bursts: Observation versus theory
Lewin, W. H. G.
1981-01-01
Results of various observations of common type I X-ray bursts are discussed with respect to the theory of thermonuclear flashes in the surface layers of accreting neutron stars. Topics covered include burst profiles; irregular burst intervals; rise and decay times and the role of hydrogen; the accuracy of source distances; accuracy in radii determination; radius increase early in the burst; the super Eddington limit; temperatures at burst maximum; and the role of the magnetic field.
Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries
International Nuclear Information System (INIS)
Hermes, J. J.; Brown, Warren R.; Kilic, Mukremin; Gianninas, A.; Chote, Paul; Sullivan, D. J.; Winget, D. E.; Bell, Keaton J.; Falcon, R. E.; Winget, K. I.; Harrold, Samuel T.; Montgomery, M. H.; Mason, Paul A.
2014-01-01
We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All of the binaries contain low-mass white dwarfs with orbital periods of less than four hr. Our observations identify the first eight tidally distorted white dwarfs, four of which are reported for the first time here. We use these observations to place empirical constraints on the mass-radius relationship for extremely low-mass (≤0.30 M ☉ ) white dwarfs. We also detect Doppler beaming in several of these binaries, which confirms their high-amplitude radial-velocity variability. All of these systems are strong sources of gravitational radiation, and long-term monitoring of those that display ellipsoidal variations can be used to detect spin-up of the tidal bulge due to orbital decay.
Radius constraints from high-speed photometry of 20 low-mass white dwarf binaries
Energy Technology Data Exchange (ETDEWEB)
Hermes, J. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Brown, Warren R. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Kilic, Mukremin; Gianninas, A. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States); Chote, Paul; Sullivan, D. J. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6140 (New Zealand); Winget, D. E.; Bell, Keaton J.; Falcon, R. E.; Winget, K. I.; Harrold, Samuel T.; Montgomery, M. H. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Mason, Paul A., E-mail: j.j.hermes@warwick.ac.uk [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States)
2014-09-01
We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf binaries known and discover systems with eclipses, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All of the binaries contain low-mass white dwarfs with orbital periods of less than four hr. Our observations identify the first eight tidally distorted white dwarfs, four of which are reported for the first time here. We use these observations to place empirical constraints on the mass-radius relationship for extremely low-mass (≤0.30 M {sub ☉}) white dwarfs. We also detect Doppler beaming in several of these binaries, which confirms their high-amplitude radial-velocity variability. All of these systems are strong sources of gravitational radiation, and long-term monitoring of those that display ellipsoidal variations can be used to detect spin-up of the tidal bulge due to orbital decay.
Effect of corner radius in stabilizing the low-Re flow past a cylinder
Zhang, Wei; Samtaney, Ravindra
2017-01-01
We perform global linear stability analysis on low-Re flow past an isolated cylinder with rounded corners. The objective of the present work is to investigate the effect of the cylinder geometry (corner radius) on the stability characteristics of the flow. Our investigation sheds light on new physics that the flow can be stabilized by partially rounding the cylinder in the critical and weakly super-critical flow regimes. The flow is first stabilized and then gradually destabilized as the cylinder varies from square to circular geometry. The sensitivity analysis reveals that the variation of stability is attributed to the different spatial variation trends of the backflow velocity in the near- and far-wake regions for various cylinder geometries. The results from the stability analysis are also verified with those of the direct simulations and very good agreement is achieved.
Effect of corner radius in stabilizing the low-Re flow past a cylinder
Zhang, Wei
2017-08-03
We perform global linear stability analysis on low-Re flow past an isolated cylinder with rounded corners. The objective of the present work is to investigate the effect of the cylinder geometry (corner radius) on the stability characteristics of the flow. Our investigation sheds light on new physics that the flow can be stabilized by partially rounding the cylinder in the critical and weakly super-critical flow regimes. The flow is first stabilized and then gradually destabilized as the cylinder varies from square to circular geometry. The sensitivity analysis reveals that the variation of stability is attributed to the different spatial variation trends of the backflow velocity in the near- and far-wake regions for various cylinder geometries. The results from the stability analysis are also verified with those of the direct simulations and very good agreement is achieved.
Detailed determination of the fusion nuclear radius in reactions involving weakly bound projectiles
International Nuclear Information System (INIS)
Gomez Camacho, A.; Aguilera, E. F.; Quiroz, E. M.
2007-01-01
A detailed determination of the fusion radius parameter is performed within the Distorted Wave Born Approximation for reactions involving weakly bound projectiles. Specifically, a simultaneous X 2- analysis of elastic and fusion cross section data is done using a Woods-Saxon potential with volume and surface parts. The volume part is assumed to be responsible for fusion reactions while the surface part for all other direct reactions. It is proved that in order to fit fusion data, particularly for energies below the Coulomb barrier where fusion is enhanced, it is necessary to have a value of around 1.4 fm for the fusion radial parameter of the fusion potential (W F ). This value is much higher than that frequently used in Barrier Penetration models (1.0 fm). The calculations are performed for reactions involving the weakly bound projectile 9 Be with several medium mass targets. (Author)
Novak, M.; Jargus, J.; Fajkus, M.; Bednarek, L.; Vasinek, V.
2017-10-01
Polydimethylsiloxane (PDMS) can be used for its optical properties and its composition offers the possibility of use in the dangerous environments. Therefore authors of this article focused on more detailed working with this material. The authors describe the use of PDMS polymer for the light transmission over short distances (up to tens of centimeters). PDMS offers good prerequisites (mechanical properties) for the creating cylindrical lighting waveguide e.g. for the purpose of the automotive industry. The objective is to determine the maximum bending radius of the cylindrical waveguide of polydimethylsiloxane for different wavelengths of the visible spectrum and thus extend the knowledge for subsequent use in lighting. The created cylindrical waveguide consist of a core and a cladding. Cladding was formed by a PDMS having a lower refractive index in order to respect the condition of total reflection.
An analog of Hölder's inequality for the spectral radius of Hadamard products
Li, Muxingzi
2017-12-03
We prove new inequalities related to the spectral radius ρ of Hadamard products (denoted by ◦ ) of complex matrices. Let p, q ∈ [1 , ∞ ] satisfy 1/p + 1/q = 1, we show an analog of Hölder’s inequality on the space of n × n complex matrices ρ ( A ◦ B ) ≤ ρ ( | A |^( ◦ p) ) ^(1/p) ρ ( | B |^( ◦ q) ) ^(1/q) for all A, B ∈ C n × n , where |·| denotes entry-wise absolute values, and ( · ) ^ (◦ p) represents the entry-wise Hadamard power. We derive a sharper inequality for the special case p = q = 2. Given A, B ∈ C ^(n × n) , for some β ∈ (0 , 1] depending on A and B , ρ ( A ◦ B ) ≤ βρ ( | A ◦ A | ) ^(1/2) ρ ( | B ◦ B | )^ (1/2) . Analysis for another special case p = 1 and q = ∞ is also included.
Effects of Odanacatib on the Radius and Tibia of Postmenopausal Women
DEFF Research Database (Denmark)
Cheung, Am; Majumdar, S; Brixen, K
2014-01-01
results, odanacatib was superior to placebo with respect to increases in trabecular volumetric BMD (vBMD) and estimated compressive strength at the spine, and integral and trabecular vBMD and estimated strength at the hip. Here we report the results of HR-pQCT assessment. 214 postmenopausal women (mean.......64% and 2.66%). At the distal radius, odanacatib significantly improved trabecular thickness and BV/TV versus placebo. At a more proximal radial site, odanacatib attenuated the increase in cortical porosity seen with placebo (treatment difference= -7.7%, p = 0.066). At the distal tibia, odanacatib...... significantly improved trabecular number, separation, and BV/TV versus placebo. Safety and tolerability were similar between treatment groups. In conclusion, odanacatib increased cortical and trabecular density, cortical thickness, aspects of trabecular microarchitecture, and estimated strength at the distal...
The convergence radius of the chiral expansion in the Dyson-Schwinger approach
International Nuclear Information System (INIS)
Meissner, T.
1994-01-01
We determine the convergence radius m conv or the expansion in the current quark mass using the Dyson-Schwinger (DS) equation of QCD in the rainbow approximation. Within a Gaussian form for the gluon propagator D μ ν(p) ∼ δμνχ 2 e - Δ /p 2 we find that m conv increases with decreasing width Δ and increasing strength χ 2 . For those values of χ 2 and Δ, which provide the best known description of low energy hadronic phenomena, m conv lies around 2Λ QCD , which is big enough, that the chiral expansion in the strange sector converges. Our analysis also explains the rather low value of m conv ∼ 50...80 MeV in the Nambu-Jona-Lasinio model, which as itself can be regarded as a special case of the rainbow DS models, where the gluon propagator is a constant in momentum space
A Silicon detector system on carbon fiber support at small radius
International Nuclear Information System (INIS)
Johnson, Marvin E.
2004-01-01
The design of a silicon detector for a p(bar p) collider experiment will be described. The detector uses a carbon fiber support structure with sensors positioned at small radius with respect to the beam. A brief overview of the mechanical design is given. The emphasis is on the electrical characteristics of the detector. General principles involved in grounding systems with carbon fiber structures will be covered. The electrical characteristics of the carbon fiber support structure will be presented. Test results imply that carbon fiber must be regarded as a conductor for the frequency region of interest of 10 to 100 MHz. No distinction is found between carbon fiber and copper. Performance results on noise due to pick-up through the low mass fine pitch cables carrying the analogue signals and floating metal is discussed
International Nuclear Information System (INIS)
Menges, R.; Dinger, U.; Boos, N.; Huber, G.; Schroeder, S.
1992-01-01
The hyperfine structure, isotope and isomeric shifts in the atomic transition 6p 2 P 3/2 -7s 2 S 1/2 , λ=535 nm have been measured for the I=7 and I=2 states of 190,192,194,196 Tl, the I=1/2 and I=9/2 states of 191 Tl and the I=7 isomer of 188 Tl. The thallium isotopes were prepared as fast atomic beams at the GSI on-line mass separator following fusion reactions and - in some cases - subsequent β-decay. The nuclear dipole moments, electric quadrupole moments and the change in the nuclear mean square charge radius are evaluated. The uu-isotopes show an isomeric shift which changes sign between 192 Tl and 194 Tl. (orig.)
Radius anomaly in the diffraction model for heavy-ion elastic scattering
Pandey, L. N.; Mukherjee, S. N.
1984-04-01
The elastic scattering of heavy ions, 20Ne on 208Pb, 20Ne on 235U, 84Kr on 208Pb, and 84Kr on 232Th, is examined within the framework of Frahn's diffraction model. An analysis of the experiment using the "quarter point recipe" of the expected Fresnel cross sections yields a larger radius for 208Pb than the radii for 235U and 232Th. It is shown that inclusion of the nuclear deformation in the model removes the above anomaly in the radii, and the assumption of smooth cutoff of the angular momentum simultaneously leads to a better fit to elastic scattering data, compared to those obtained by the earlier workers on the assumption of sharp cutoff. [NUCLEAR REACTIONS Elastic scattering, 20Ne+208Pb (161.2 MeV), 20Ne+235U (175 MeV), 84Kr+208Pb (500 MeV), 84Kr+232Th (500 MeV), diffraction model, nuclear deformation.
Noncircular features in Saturn's rings IV: Absolute radius scale and Saturn's pole direction
French, Richard G.; McGhee-French, Colleen A.; Lonergan, Katherine; Sepersky, Talia; Jacobson, Robert A.; Nicholson, Philip D.; Hedman, Mathew M.; Marouf, Essam A.; Colwell, Joshua E.
2017-07-01
We present a comprehensive solution for the geometry of Saturn's ring system, based on orbital fits to an extensive set of occultation observations of 122 individual ring edges and gaps. We begin with a restricted set of very high quality Cassini VIMS, UVIS, and RSS measurements for quasi-circular features in the C and B rings and the Cassini Division, and then successively add suitably weighted additional Cassini and historical occultation measurements (from Voyager, HST and the widely-observed 28 Sgr occultation of 3 Jul 1989) for additional non-circular features, to derive an absolute radius scale applicable across the entire classical ring system. As part of our adopted solution, we determine first-order corrections to the spacecraft trajectories used to determine the geometry of individual occultation chords. We adopt a simple linear model for Saturn's precession, and our favored solution yields a precession rate on the sky n^˙P = 0.207 ± 0 .006‧‧yr-1 , equivalent to an angular rate of polar motion ΩP = 0.451 ± 0 .014‧‧yr-1 . The 3% formal uncertainty in the fitted precession rate is approaching the point where it can provide a useful constraint on models of Saturn's interior, although realistic errors are likely to be larger, given the linear approximation of the precession model and possible unmodeled systematic errors in the spacecraft ephemerides. Our results are largely consistent with independent estimates of the precession rate based on historical RPX times (Nicholson et al., 1999 AAS/Division for Planetary Sciences Meeting Abstracts #31 31, 44.01) and from theoretical expectations that account for Titan's 700-yr precession period (Vienne and Duriez 1992, Astronomy and Astrophysics 257, 331-352). The fitted precession rate based on Cassini data only is somewhat lower, which may be an indication of unmodeled shorter term contributions to Saturn's polar motion from other satellites, or perhaps the result of inconsistencies in the assumed
Cosmic clocks: a tight radius-velocity relationship for H I-selected galaxies
Meurer, Gerhardt R.; Obreschkow, Danail; Wong, O. Ivy; Zheng, Zheng; Audcent-Ross, Fiona M.; Hanish, D. J.
2018-05-01
H I-selected galaxies obey a linear relationship between their maximum detected radius Rmax and rotational velocity. This result covers measurements in the optical, ultraviolet, and H I emission in galaxies spanning a factor of 30 in size and velocity, from small dwarf irregulars to the largest spirals. Hence, galaxies behave as clocks, rotating once a Gyr at the very outskirts of their discs. Observations of a large optically selected sample are consistent, implying this relationship is generic to disc galaxies in the low redshift Universe. A linear radius-velocity relationship is expected from simple models of galaxy formation and evolution. The total mass within Rmax has collapsed by a factor of 37 compared to the present mean density of the Universe. Adopting standard assumptions, we find a mean halo spin parameter λ in the range 0.020-0.035. The dispersion in λ, 0.16 dex, is smaller than expected from simulations. This may be due to the biases in our selection of disc galaxies rather than all haloes. The estimated mass densities of stars and atomic gas at Rmax are similar (˜0.5 M⊙ pc-2), indicating outer discs are highly evolved. The gas consumption and stellar population build time-scales are hundreds of Gyr, hence star formation is not driving the current evolution of outer discs. The estimated ratio between Rmax and disc scalelength is consistent with long-standing predictions from monolithic collapse models. Hence, it remains unclear whether disc extent results from continual accretion, a rapid initial collapse, secular evolution, or a combination thereof.
REVERBERATION AND PHOTOIONIZATION ESTIMATES OF THE BROAD-LINE REGION RADIUS IN LOW-z QUASARS
Energy Technology Data Exchange (ETDEWEB)
Negrete, C. Alenka [Instituto Nacional de Astrofisica, Optica y Electronica (Mexico); Dultzin, Deborah [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico (Mexico); Marziani, Paola [INAF, Astronomical Observatory of Padova, I-35122 Padova (Italy); Sulentic, Jack W., E-mail: cnegrete@inaoep.mx, E-mail: deborah@astro.unam.mx, E-mail: paola.marziani@oapd.inaf.it, E-mail: sulentic@iaa.es [Instituto de Astrofisica de Andalucia, E-18008 Granada (Spain)
2013-07-01
Black hole mass estimation in quasars, especially at high redshift, involves the use of single-epoch spectra with signal-to-noise ratio and resolution that permit accurate measurement of the width of a broad line assumed to be a reliable virial estimator. Coupled with an estimate of the radius of the broad-line region (BLR) this yields the black hole mass M{sub BH}. The radius of the BLR may be inferred from an extrapolation of the correlation between source luminosity and reverberation-derived r{sub BLR} measures (the so-called Kaspi relation involving about 60 low-z sources). We are exploring a different method for estimating r{sub BLR} directly from inferred physical conditions in the BLR of each source. We report here on a comparison of r{sub BLR} estimates that come from our method and from reverberation mapping. Our ''photoionization'' method employs diagnostic line intensity ratios in the rest-frame range 1400-2000 A (Al III {lambda}1860/Si III] {lambda}1892, C IV {lambda}1549/Al III {lambda}1860) that enable derivation of the product of density and ionization parameter with the BLR distance derived from the definition of the ionization parameter. We find good agreement between our estimates of the density, ionization parameter, and r{sub BLR} and those from reverberation mapping. We suggest empirical corrections to improve the agreement between individual photoionization-derived r{sub BLR} values and those obtained from reverberation mapping. The results in this paper can be exploited to estimate M{sub BH} for large samples of high-z quasars using an appropriate virial broadening estimator. We show that the width of the UV intermediate emission lines are consistent with the width of H{beta}, thereby providing a reliable virial broadening estimator that can be measured in large samples of high-z quasars.
Ferree, Steven; van der Vliet, Quirine M J; Nawijn, Femke; Bhashyam, Abhiram R; Houwert, Roderick M; Leenen, Luke P H; Hietbrink, Falco
2018-03-01
For several extremity fractures differences in morphology, incidence rate and functional outcome were found when polytrauma patients were compared to patients with an isolated injury. This is not proven for distal radius fractures (DRF). Therefore, this study aimed to analyse fracture morphology in relation to energy transfer in both poly- and mono-trauma patients with a DRF. This was a retrospective cohort study. All patients aged 16 years and older with a DRF were included. Patients with an Injury Severity Score of 16 or higher were classified as polytrauma patients. Injuries were defined as high or low energy. All DRFs were classified using the AO/OTA fracture classification system. A total of 830 patients with a DRF were included, 12% were polytrauma. The incidence rate of DRF in polytrauma patients was 3.5%. Ipsilateral upper extremity injury was found in >30% of polytrauma and high-energy monotrauma patients, compared to 5% in low-energy monotrauma patients. More type C DRF were found in polytrauma and high-energy monotrauma patients versus low-energy monotrauma patients. Operative intervention rates for all types of DRF were similar for polytrauma and high-energy monotrauma patients. Non-union rates were higher in polytrauma patients. Higher energy mechanisms of injury, in polytrauma and high-energy monotrauma patients, were associated with more severe complex articular distal radius fractures and more ipsilateral upper extremity injuries. Polytrauma and high-energy monotrauma patient have a similar fracture morphology. However, polytrauma patients have in addition to more injured body regions also more non-union related interventions than high-energy monotrauma patients. Copyright © 2018 Elsevier Ltd. All rights reserved.
THE LOW-LUMINOSITY END OF THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI
International Nuclear Information System (INIS)
Bentz, Misty C.; Denney, Kelly D.; Vestergaard, Marianne; Grier, Catherine J.; Peterson, Bradley M.; De Rosa, Gisella; Pogge, Richard W.; Barth, Aaron J.; Bennert, Vardha N.; Canalizo, Gabriela; Filippenko, Alexei V.; Li Weidong; Gates, Elinor L.; Greene, Jenny E.; Malkan, Matthew A.; Stern, Daniel; Treu, Tommaso; Woo, Jong-Hak
2013-01-01
We present an updated and revised analysis of the relationship between the Hβ broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the Hβ time lag, which is assumed to yield the average Hβ BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R BLR -L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of α= 0.533 +0.035 -0.033 , consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19 ± 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R BLR -L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.
THE LOW-LUMINOSITY END OF THE RADIUS-LUMINOSITY RELATIONSHIP FOR ACTIVE GALACTIC NUCLEI
Energy Technology Data Exchange (ETDEWEB)
Bentz, Misty C. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Denney, Kelly D.; Vestergaard, Marianne [Dark Cosmology Center, Niels Bohr Institute, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Grier, Catherine J.; Peterson, Bradley M.; De Rosa, Gisella; Pogge, Richard W. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Bennert, Vardha N. [Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407 (United States); Canalizo, Gabriela [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States); Filippenko, Alexei V.; Li Weidong [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Gates, Elinor L. [University of California Observatories/Lick Observatory, P.O. Box 85, Mount Hamilton, CA 95140 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Peyton Hall - Ivy Lane, Princeton, NJ 08544 (United States); Malkan, Matthew A. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Treu, Tommaso [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Woo, Jong-Hak, E-mail: bentz@chara.gsu.edu [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul (Korea, Republic of)
2013-04-20
We present an updated and revised analysis of the relationship between the H{beta} broad-line region (BLR) radius and the luminosity of the active galactic nucleus (AGN). Specifically, we have carried out two-dimensional surface brightness decompositions of the host galaxies of nine new AGNs imaged with the Hubble Space Telescope Wide Field Camera 3. The surface brightness decompositions allow us to create ''AGN-free'' images of the galaxies, from which we measure the starlight contribution to the optical luminosity measured through the ground-based spectroscopic aperture. We also incorporate 20 new reverberation-mapping measurements of the H{beta} time lag, which is assumed to yield the average H{beta} BLR radius. The final sample includes 41 AGNs covering four orders of magnitude in luminosity. The additions and updates incorporated here primarily affect the low-luminosity end of the R{sub BLR}-L relationship. The best fit to the relationship using a Bayesian analysis finds a slope of {alpha}= 0.533{sup +0.035}{sub -0.033}, consistent with previous work and with simple photoionization arguments. Only two AGNs appear to be outliers from the relationship, but both of them have monitoring light curves that raise doubt regarding the accuracy of their reported time lags. The scatter around the relationship is found to be 0.19 {+-} 0.02 dex, but would be decreased to 0.13 dex by the removal of these two suspect measurements. A large fraction of the remaining scatter in the relationship is likely due to the inaccurate distances to the AGN host galaxies. Our results help support the possibility that the R{sub BLR}-L relationship could potentially be used to turn the BLRs of AGNs into standardizable candles. This would allow the cosmological expansion of the universe to be probed by a separate population of objects, and over a larger range of redshifts.
Assessment of "YouTube" Content for Distal Radius Fracture Immobilization.
Addar, Abdullah; Marwan, Yousef; Algarni, Nizar; Berry, Gregory
Distal radius fractures (DRFs) are the most common orthopedic fractures, with >70% of cases treated by closed immobilization using a short arm cast or a sugar tong splint. However, inadequate immobilization is a risk factor for loss of reduction requiring repeat reduction or surgical treatment. Therefore, education of clinical skills for appropriate immobilization of DRFs is important. With the increasing use of web-based information by medical learners, our aim was to assess the quality and quantity of videos regarding closed immobilization of DRFs on YouTube. Retrospective review of YouTube videos on distal radius fracture immobilization using specific search terms. Identified videos were analyzed for their educational value, quality of the technical skill demonstrated, and overall metrics. Educational value was scored on a 5-point scale, with "1" indicative of low quality and "5" of high quality. Not applicable. Among the 68,366 videos identified, 16 met our inclusion criteria of being in English; performed by a health care professional or institution; and with casting being the major theme of the educational information provided. Of these 16 videos, 6 had an educational value score of 4 or 5, with the remaining 10 having a score ≤3. Although immobilization was demonstrated by cast technician specialized in orthopedics, skills were also performed by orthopedic attendants, urgent care physicians, orthopedic residents, and nurse practitioners. The credentials of the performer in 3 videos were not identified. There is a need to promote high-quality educational videos produced by established medical school faculty members on open, web-based, portals. Copyright © 2017 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.
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Jaremko, J.L.; Lambert, R.G.W.; Rowe, B.H.; Johnson, J.A.; Majumdar, S.R.
2007-01-01
Aim: To investigate whether radiographic deformities suggesting inadequate reduction would be associated with adverse clinical outcomes. Materials and methods: Consecutive patients over 50 years of age (n = 74) with non-operatively managed distal radius fractures were enrolled in a prospective cohort study. They had radiographs at cast removal (∼6 weeks) and completed DASH (Disabilities of the Arm, Shoulder and Hand), SF-12 (health-related quality of life), and satisfaction surveys 6-months post-fracture. A reference-standard musculoskeletal radiologist, blinded to outcomes status, measured palmar (dorsal) tilt, radial angle, radial height, ulnar height, and intra-articular step and gap. Radiographic indices were correlated to each other and to the various patient-reported outcomes in univariate and multivariate regression analyses. DASH score was the primary study outcome. Results: Of the cohort studied (n = 74, mean age 68.5 years, primarily white women), 71% had at least one 'unacceptable' radiographic deformity by traditional criteria. Acceptable reduction varied from 60-99% depending on which single index was reported, and 44% of patients had more than two indices reported as unacceptable. Despite these radiographic findings, 6-months post-reduction, self-reported disability was low (DASH = 24 ± 17), health-related quality of life was near normal, and 72% were satisfied with their care. No radiographic index of wrist deformity (alone or in combination) was significantly correlated to any of the patient-reported outcomes. Conclusion: Self-reported outcomes in older adults with conservatively managed wrist fractures were not related to the 'acceptability' of radiographic fracture reduction. The proportion of acceptable reductions varied by 40% depending on which index was reported. Consequently, detailed reporting of these indices in older adults with distal radius fracture may be inefficient or perhaps even unnecessary
Effect of facility on the operative costs of distal radius fractures.
Mather, Richard C; Wysocki, Robert W; Mack Aldridge, J; Pietrobon, Ricardo; Nunley, James A
2011-07-01
The purpose of this study was to investigate whether ambulatory surgery centers can deliver lower-cost care and to identify sources of those cost savings. We performed a cost identification analysis of outpatient volar plating for closed distal radius fractures at a single academic medical center. Multiple costs and time measures were taken from an internal database of 130 consecutive patients and were compared by venue of treatment, either an inpatient facility or an ambulatory, stand-alone surgery facility. The relationships between total cost and operative time and multiple variables, including fracture severity, patient age, gender, comorbidities, use of bone graft, concurrent carpal tunnel release, and surgeon experience, were examined, using multivariate analysis and regression modeling to identify other cost drivers or explanatory variables. The mean operative cost was considerably greater at the inpatient facility ($7,640) than at the outpatient facility ($5,220). Cost drivers of this difference were anesthesia services, post-anesthesia care unit, and operating room costs. Total surgical time, nursing time, set-up, and operative times were 33%, 109%, 105%, and 35% longer, respectively, at the inpatient facility. There was no significant difference between facilities for the additional variables, and none of those variables independently affected cost or operative time. The only predictor of cost and time was facility type. This study supports the use of ambulatory stand-alone surgical facilities to achieve efficient resource utilization in the operative treatment of distal radius fractures. We also identified several specific costs and time measurements that differed between facilities, which can serve as potential targets for tertiary facilities to improve utilization. Economic and Decisional Analysis III. Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.
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Jaremko, J.L. [Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta (Canada); Lambert, R.G.W. [Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, Alberta (Canada); Rowe, B.H. [Department of Emergency Medicine, University of Alberta, Edmonton, Alberta (Canada); Department of Public Health Sciences, University of Alberta, Edmonton, Alberta (Canada); Johnson, J.A. [Department of Public Health Sciences, University of Alberta, Edmonton, Alberta (Canada); Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta (Canada); Majumdar, S.R. [Department of Public Health Sciences, University of Alberta, Edmonton, Alberta (Canada) and Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta (Canada)]. E-mail: me2.majumdar@ualberta.ca
2007-01-15
Aim: To investigate whether radiographic deformities suggesting inadequate reduction would be associated with adverse clinical outcomes. Materials and methods: Consecutive patients over 50 years of age (n = 74) with non-operatively managed distal radius fractures were enrolled in a prospective cohort study. They had radiographs at cast removal ({approx}6 weeks) and completed DASH (Disabilities of the Arm, Shoulder and Hand), SF-12 (health-related quality of life), and satisfaction surveys 6-months post-fracture. A reference-standard musculoskeletal radiologist, blinded to outcomes status, measured palmar (dorsal) tilt, radial angle, radial height, ulnar height, and intra-articular step and gap. Radiographic indices were correlated to each other and to the various patient-reported outcomes in univariate and multivariate regression analyses. DASH score was the primary study outcome. Results: Of the cohort studied (n = 74, mean age 68.5 years, primarily white women), 71% had at least one 'unacceptable' radiographic deformity by traditional criteria. Acceptable reduction varied from 60-99% depending on which single index was reported, and 44% of patients had more than two indices reported as unacceptable. Despite these radiographic findings, 6-months post-reduction, self-reported disability was low (DASH = 24 {+-} 17), health-related quality of life was near normal, and 72% were satisfied with their care. No radiographic index of wrist deformity (alone or in combination) was significantly correlated to any of the patient-reported outcomes. Conclusion: Self-reported outcomes in older adults with conservatively managed wrist fractures were not related to the 'acceptability' of radiographic fracture reduction. The proportion of acceptable reductions varied by 40% depending on which index was reported. Consequently, detailed reporting of these indices in older adults with distal radius fracture may be inefficient or perhaps even unnecessary.
Limited arthrodesis of the wrist for treatment of giant cell tumor of the distal radius.
Flouzat-Lachaniette, Charles-Henri; Babinet, Antoine; Kahwaji, Antoine; Anract, Philippe; Biau, David-Jean
2013-08-01
To present the functional results of a technique of radiocarpal arthrodesis and reconstruction with a structural nonvascularized autologous bone graft after en bloc resection of giant cell tumors of the distal radius. A total of 13 patients with a mean age of 37 years with aggressive giant cell tumor (Campanacci grade III) of distal radius were managed with en bloc resection and reconstruction with a structural nonvascularized bone graft. The primary outcome measure was the disability evaluated by the Musculoskeletal Tumor Society rating score of limb salvage. Secondary outcomes included survival of the reconstruction measured from the date of the operation to revision procedure for any reason (mechanical, infectious, or oncologic). Other outcomes included active wrist motion and ability to resume work. Mean follow-up period was 6 years (range, 2-14 y). The median arc of motion at the midcarpal joint was 40°, median wrist flexion was 20°, and median extension was 10°. The median Musculoskeletal Tumor Society score based on the analysis of factors pertinent to the patient as a whole (pain, functional activities, and emotional acceptance) and specific to the upper limb (positioning of the hand, manual dexterity, and lifting ability) was 86%. Five patients underwent a second surgical procedure. The cumulative probability of reoperation for mechanical reason was 31% at similar follow-up times at 2, 5, and 10 years. This technique provided a stable wrist and partially restored wrist motion with limited pain. However, further surgical procedures may be necessary to reach this goal. Therapeutic IV. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.
String theory or field theory?
International Nuclear Information System (INIS)
Marshakov, A.V.
2002-01-01
The status of string theory is reviewed, and major recent developments - especially those in going beyond perturbation theory in the string theory and quantum field theory frameworks - are analyzed. This analysis helps better understand the role and place of experimental phenomena, it is emphasized that there are some insurmountable problems inherent in it - notably the impossibility to formulate the quantum theory of gravity on its basis - which prevent it from being a fundamental physical theory of the world of microscopic distances. It is this task, the creation of such a theory, which string theory, currently far from completion, is expected to solve. In spite of its somewhat vague current form, string theory has already led to a number of serious results and greatly contributed to progress in the understanding of quantum field theory. It is these developments, which are our concern in this review [ru
Higher spin gauge theories in any dimension
International Nuclear Information System (INIS)
Vasiliev, M.A.
2004-01-01
Some general properties of higher spin (HS) gauge theories are summarized, with the emphasize on the nonlinear theories in any dimension. The main conclusion is that nonlinear HS theories exist in any dimension. Note that HS gauge symmetries in the nonlinear HS theory differ from the Yang-Mills gauging of the global HS symmetry of a free theory one starts with by HS field strength dependent nonlinear corrections resulting from the partial gauge fixing of spontaneously broken HS symmetries in the extended non-commutative space. The HS geometry is that of the fuzzy hyperboloid in the auxiliary (fiber) non-commutative space. Its radius depends on the Weyl 0-forms which take values in the infinitive-dimensional module dual to the space of single-particle states in the system
International Nuclear Information System (INIS)
Uehara, S.
1985-01-01
Of all supergravity theories, the maximal, i.e., N = 8 in 4-dimension or N = 1 in 11-dimension, theory should perform the unification since it owns the highest degree of symmetry. As to the N = 1 in d = 11 theory, it has been investigated how to compactify to the d = 4 theories. From the phenomenological point of view, local SUSY GUTs, i.e., N = 1 SUSY GUTs with soft breaking terms, have been studied from various angles. The structures of extended supergravity theories are less understood than those of N = 1 supergravity theories, and matter couplings in N = 2 extended supergravity theories are under investigation. The harmonic superspace was recently proposed which may be useful to investigate the quantum effects of extended supersymmetry and supergravity theories. As to the so-called Kaluza-Klein supergravity, there is another possibility. (Mori, K.)
Johnstone, PT
2014-01-01
Focusing on topos theory's integration of geometric and logical ideas into the foundations of mathematics and theoretical computer science, this volume explores internal category theory, topologies and sheaves, geometric morphisms, other subjects. 1977 edition.
Dorogovtsev, A Ya; Skorokhod, A V; Silvestrov, D S; Skorokhod, A V
1997-01-01
This book of problems is intended for students in pure and applied mathematics. There are problems in traditional areas of probability theory and problems in the theory of stochastic processes, which has wide applications in the theory of automatic control, queuing and reliability theories, and in many other modern science and engineering fields. Answers to most of the problems are given, and the book provides hints and solutions for more complicated problems.
International Nuclear Information System (INIS)
Lee, B.W.
1976-01-01
Some introductory remarks to Yang-Mills fields are given and the problem of the Coulomb gauge is considered. The perturbation expansion for quantized gauge theories is discussed and a survey of renormalization schemes is made. The role of Ward-Takahashi identities in gauge theories is discussed. The author then discusses the renormalization of pure gauge theories and theories with spontaneously broken symmetry. (B.R.H.)
Magnus, Charlene R A; Arnold, Cathy M; Johnston, Geoffrey; Dal-Bello Haas, Vanina; Basran, Jenny; Krentz, Joel R; Farthing, Jonathan P
2013-07-01
To evaluate the effects of cross-education (contralateral effect of unilateral strength training) during recovery from unilateral distal radius fractures on muscle strength, range of motion (ROM), and function. Randomized controlled trial (26-wk follow-up). Hospital, orthopedic fracture clinic. Women older than 50 years with a unilateral distal radius fracture. Fifty-one participants were randomized and 39 participants were included in the final data analysis. Participants were randomized to standard rehabilitation (Control) or standard rehabilitation plus strength training (Train). Standard rehabilitation included forearm casting for 40.4±6.2 days and hand exercises for the fractured extremity. Nonfractured hand strength training for the training group began immediately postfracture and was conducted at home 3 times/week for 26 weeks. The primary outcome measure was peak force (handgrip dynamometer). Secondary outcomes were ROM (flexion/extension; supination/pronation) via goniometer and the Patient Rated Wrist Evaluation questionnaire score for the fractured arm. For the fractured hand, the training group (17.3±7.4kg) was significantly stronger than the control group (11.8±5.8kg) at 12 weeks postfracture (P<.017). There were no significant strength differences between the training and control groups at 9 (12.5±8.2kg; 11.3±6.9kg) or 26 weeks (23.0±7.6kg; 19.6±5.5kg) postfracture, respectively. Fractured hand ROM showed that the training group had significantly improved wrist flexion/extension (100.5°±19.2°) than the control group (80.2°±18.7°) at 12 weeks postfracture (P<.017). There were no significant differences between the training and control groups for flexion/extension ROM at 9 (78.0°±20.7°; 81.7°±25.7°) or 26 weeks (104.4°±15.5°; 106.0°±26.5°) or supination/pronation ROM at 9 (153.9°±23.9°; 151.8°±33.0°), 12 (170.9°±9.3°; 156.7°±20.8°) or 26 weeks (169.4°±11.9°; 162.8°±18.1°), respectively. There were no
Multi-Segment Radius Measurement Using an Absolute Distance Meter Through a Null Assembly
Merle, Cormic; Wick, Eric; Hayden, Joseph
2011-01-01
This system was one of the test methods considered for measuring the radius of curvature of one or more of the 18 segmented mirrors that form the 6.5 m diameter primary mirror (PM) of the James Webb Space Telescope (JWST). The assembled telescope will be tested at cryogenic temperatures in a 17-m diameter by 27-m high vacuum chamber at the Johnson Space Center. This system uses a Leica Absolute Distance Meter (ADM), at a wavelength of 780 nm, combined with beam-steering and beam-shaping optics to make a differential distance measurement between a ring mirror on the reflective null assembly and individual PM segments. The ADM is located inside the same Pressure-Tight Enclosure (PTE) that houses the test interferometer. The PTE maintains the ADM and interferometer at ambient temperature and pressure so that they are not directly exposed to the telescope s harsh cryogenic and vacuum environment. This system takes advantage of the existing achromatic objective and reflective null assembly used by the test interferometer to direct four ADM beamlets to four PM segments through an optical path that is coincident with the interferometer beam. A mask, positioned on a linear slide, contains an array of 1.25 mm diameter circular subapertures that map to each of the 18 PM segments as well as six positions around the ring mirror. A down-collimated 4 mm ADM beam simultaneously covers 4 adjacent PM segment beamlets and one ring mirror beamlet. The radius, or spacing, of all 18 segments can be measured with the addition of two orthogonally-oriented scanning pentaprisms used to steer the ADM beam to any one of six different sub-aperture configurations at the plane of the ring mirror. The interferometer beam, at a wavelength of 687 nm, and the ADM beamlets, at a wavelength of 780 nm, pass through the objective and null so that the rays are normally incident on the parabolic PM surface. After reflecting off the PM, both the ADM and interferometer beams return to their respective
Tremblin, P.; Chabrier, G.; Mayne, N. J.; Amundsen, D. S.; Baraffe, I.; Debras, F.; Drummond, B.; Manners, J.; Fromang, S.
2017-01-01
The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. Based on a two-dimensional steady-state atmospheric circulation model, the validity of which is assessed by comparison to three-dimensional calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass and longitudinal momentum conservation, a process occurring in the Earth's atmosphere or oceans. In the deep atmosphere, the vanishing heating flux forces the atmospheric structure to converge to a hotter adiabat than the one obtained with 1D calculations, implying a larger radius for the planet. Not only do the calculations reproduce the observed radius of HD 209458b, but also reproduce the observed correlation between radius inflation and irradiation for transiting planets. Vertical advection of potential temperature induced by non-uniform atmospheric heating thus provides a robust mechanism to explain the inflated radii of irradiated hot Jupiters.
International Nuclear Information System (INIS)
Tremblin, P.; Chabrier, G.; Mayne, N. J.; Baraffe, I.; Debras, F.; Drummond, B.; Manners, J.; Amundsen, D. S.; Fromang, S.
2017-01-01
The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. Based on a two-dimensional steady-state atmospheric circulation model, the validity of which is assessed by comparison to three-dimensional calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass and longitudinal momentum conservation, a process occurring in the Earth’s atmosphere or oceans. In the deep atmosphere, the vanishing heating flux forces the atmospheric structure to converge to a hotter adiabat than the one obtained with 1D calculations, implying a larger radius for the planet. Not only do the calculations reproduce the observed radius of HD 209458b, but also reproduce the observed correlation between radius inflation and irradiation for transiting planets. Vertical advection of potential temperature induced by non-uniform atmospheric heating thus provides a robust mechanism to explain the inflated radii of irradiated hot Jupiters.
Obeidat, Abdalla; Jaradat, Adnan; Hamdan, Bushra; Abu-Ghazleh, Hind
2018-04-01
The best spherical cutoff radius, long range interaction and temperature controller were determined using surface tension, density, and diffusion coefficients of van Leeuwen and Smit methanol. A quite good range of cutoff radii from 0.75 to 1.45 nm has been studied on Coulomb cut-off and particle mesh Ewald (PME) long range interaction to determine the best cutoff radius and best long range interaction as well for four sets of temperature: 200, 230, 270 and 300 K. To determine the best temperature controller, the cutoff radius of 1.25 nm was fixed using PME long range interaction on calculating the above properties at low temperature range: 200-300 K.
Energy Technology Data Exchange (ETDEWEB)
Tremblin, P. [Maison de la Simulation, CEA-CNRS-INRIA-UPS-UVSQ, USR 3441, CEA Paris-Saclay, F-91191 Gif-Sur-Yvette (France); Chabrier, G.; Mayne, N. J.; Baraffe, I.; Debras, F.; Drummond, B.; Manners, J. [Astrophysics Group, University of Exeter, EX4 4QL Exeter (United Kingdom); Amundsen, D. S. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10025 (United States); Fromang, S., E-mail: pascal.tremblin@cea.fr [Laboratoire AIM, CEA/DSM-CNRS-Université Paris 7, Irfu/Service d’Astrophysique, CEA Paris-Saclay, F-91191 Gif-sur-Yvette (France)
2017-05-20
The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. Based on a two-dimensional steady-state atmospheric circulation model, the validity of which is assessed by comparison to three-dimensional calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass and longitudinal momentum conservation, a process occurring in the Earth’s atmosphere or oceans. In the deep atmosphere, the vanishing heating flux forces the atmospheric structure to converge to a hotter adiabat than the one obtained with 1D calculations, implying a larger radius for the planet. Not only do the calculations reproduce the observed radius of HD 209458b, but also reproduce the observed correlation between radius inflation and irradiation for transiting planets. Vertical advection of potential temperature induced by non-uniform atmospheric heating thus provides a robust mechanism to explain the inflated radii of irradiated hot Jupiters.
Shimamura, Miyuki K; Deguchi, Tetsuo
2002-05-01
Several nontrivial properties are shown for the mean-square radius of gyration R2(K) of ring polymers with a fixed knot type K. Through computer simulation, we discuss both finite size and asymptotic behaviors of the gyration radius under the topological constraint for self-avoiding polygons consisting of N cylindrical segments with radius r. We find that the average size of ring polymers with the knot K can be much larger than that of no topological constraint. The effective expansion due to the topological constraint depends strongly on the parameter r that is related to the excluded volume. The topological expansion is particularly significant for the small r case, where the simulation result is associated with that of random polygons with the knot K.
Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC
Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj
2015-02-01
Jets with a large radius R ≳ 1 and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large- R jet configurations used by the LHC experiments is jet re-clustering. Jet re-clustering introduces an intermediate scale r groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.
International Nuclear Information System (INIS)
Cuntz, M.; Yeager, K. E.
2009-01-01
We challenge the customary assumption that the entering of an Earth-mass planet into the Hill radius (or multiples of the Hill radius) of a giant planet is a valid criterion for its ejection from the star-planet system. This assumption has widely been used in previous studies, especially those with an astrobiological focus. As intriguing examples, we explore the dynamics of the systems HD 20782 and HD 188015. Each system possesses a giant planet that remains in or crosses into the stellar habitable zone, thus effectively thwarting the possibility of habitable terrestrial planets. In the case of HD 188015, the orbit of the giant planet is almost circular, whereas in the case of HD 20782, it is extremely elliptical. Although it is found that Earth-mass planets are eventually ejected from the habitable zones of these systems, the 'Hill Radius Criterion' is identified as invalid for the prediction of when the ejection is actually occurring.
A study of the required Rayleigh number to sustain dynamo with various inner core radius
Nishida, Y.; Katoh, Y.; Matsui, H.; Kumamoto, A.
2017-12-01
It is widely accepted that the geomagnetic field is sustained by thermal and compositional driven convections of a liquid iron alloy in the outer core. The generation process of the geomagnetic field has been studied by a number of MHD dynamo simulations. Recent studies of the ratio of the Earth's core evolution suggest that the inner solid core radius ri to the outer liquid core radius ro changed from ri/ro = 0 to 0.35 during the last one billion years. There are some studies of dynamo in the early Earth with smaller inner core than the present. Heimpel et al. (2005) revealed the Rayleigh number Ra of the onset of dynamo process as a function of ri/ro from simulation, while paleomagnetic observation shows that the geomagnetic field has been sustained for 3.5 billion years. While Heimpel and Evans (2013) studied dynamo processes taking into account the thermal history of the Earth's interior, there were few cases corresponding to the early Earth. Driscoll (2016) performed a series of dynamo based on a thermal evolution model. Despite a number of dynamo simulations, dynamo process occurring in the interior of the early Earth has not been fully understood because the magnetic Prandtl numbers in these simulations are much larger than that for the actual outer core.In the present study, we performed thermally driven dynamo simulations with different aspect ratio ri/ro = 0.15, 0.25 and 0.35 to evaluate the critical Ra for the thermal convection and required Ra to maintain the dynamo. For this purpose, we performed simulations with various Ra and fixed the other control parameters such as the Ekman, Prandtl, and magnetic Prandtl numbers. For the initial condition and boundary conditions, we followed the dynamo benchmark case 1 by Christensen et al. (2001). The results show that the critical Ra increases with the smaller aspect ratio ri/ro. It is confirmed that larger amplitude of buoyancy is required in the smaller inner core to maintain dynamo.
Anatomical study of the radius and center of curvature of the distal femoral condyle
Kosel, Jü rgen; Giouroudi, Ioanna; Scheffer, Cornie; Dillon, Edwin Mark; Erasmus, Pieter J.
2010-01-01
In this anatomical study, the anteroposterior curvature of the surface of 16 cadaveric distal femurs was examined in terms of radii and center point. Those two parameters attract high interest due to their significance for total knee arthroplasty. Basically, two different conclusions have been drawn in foregoing studies: (1) The curvature shows a constant radius and (2) the curvature shows a variable radius. The investigations were based on a new method combining three-dimensional laser-scanning and planar geometrical analyses. This method is aimed at providing high accuracy and high local resolution. The high-precision laser scanning enables the exact reproduction of the distal femurs - including their cartilage tissue - as a three-dimensional computer model. The surface curvature was investigated on intersection planes that were oriented perpendicularly to the surgical epicondylar line. Three planes were placed at the central part of each condyle. The intersection of either plane with the femur model was approximated with the help of a b-spline, yielding three b-splines on each condyle. The radii and center points of the circles, approximating the local curvature of the b-splines, were then evaluated. The results from all three b-splines were averaged in order to increase the reliability of the method. The results show the variation in the surface curvatures of the investigated samples of condyles. These variations are expressed in the pattern of the center points and the radii of the curvatures. The standard deviations of the radii for a 90 deg arc on the posterior condyle range from 0.6 mm up to 5.1 mm, with an average of 2.4 mm laterally and 2.2 mm medially. No correlation was found between the curvature of the lateral and medial condyles. Within the range of the investigated 16 samples, the conclusion can be drawn that the condyle surface curvature is not constant and different for all specimens when viewed along the surgical epicondylar axis. For the portion
A STUDY ON FRACTURE FIXATION OF DISTAL END OF RADIUS BY PERCUTANEOUS PINNING
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Kiran Kumar L
2016-07-01
Full Text Available BACKGROUND Various treatment modalities have been described for the treatment of distal radius fractures each with its own merits and demerits. Most of the work done with percutaneous pinning has shown a significant residual stiffness of the hand and wrist. Our technique involves percutaneous pinning of the fracture and immobilisation in neutral position of the wrist for. This study's aim was to examine the functional outcome of percutaneous K-wiring of these distal radius fractures with immobilisation in neutral position of the wrist. METHODS A prospective study conducted on thirty adult patients with distal radial fractures treated at Department of Orthopaedics, Rangaraya Medical college, Kakinada between October 2013 to September 2015. RADIOGRAPHIC EXAMINATION Standard radiographs in PA and lateral views were taken for confirmation of the diagnosis and also to know the type of fracture. Oblique views were also taken in a few patients who had complex comminuted fractures. The fracture fragments were analysed and involvement of radiocarpal and distal radioulnar joints were assessed and classified according to the Frykman classification. Of the cases, 6(20% of the fractures were type I, 2(6.6% of type II, 3(10% of type III, 6(20% of type IV, 8(26.6% of type V, 5(16.6% of type VI, no cases of type VII and VIII.SURGICAL PROCEDURE The procedures were performed under regional anaesthesia in all cases. After sterile preparation and draping, fracture is reduced by traction and the reduction was evaluated fluoroscopically. A 1.5 cm incision given longitudinally (if needed beginning at the radial styloid and proceeds proximally across to the medial metaphysis and diaphysis. At least two pins (1.6 mm Kirschner wire were inserted and adequate reduction was confirmed on AP/LAT views under image intensifier. Another 1.6 mm K-wire percutaneously 90 degrees orthogonally to these wires starting at the dorsal rim of distal radius just distal to the Lister
Byers, John A
2008-09-01
The release rate of a semiochemical lure that attracts flying insects has a specific effective attraction radius (EAR) that corresponds to the lure's orientation response strength. EAR is defined as the radius of a passive sphere that intercepts the same number of insects as a semiochemical-baited trap. It is estimated by calculating the ratio of trap catches in the field in baited and unbaited traps and the interception area of the unbaited trap. EAR serves as a standardized method for comparing the attractive strengths of lures that is independent of population density. In two-dimensional encounter rate models that are used to describe insect mass trapping and mating disruption, a circular EAR (EAR(c)) describes a key parameter that affects catch or influence by pheromone in the models. However, the spherical EAR, as measured in the field, should be transformed to an EAR(c) for appropriate predictions in such models. The EAR(c) is calculated as (pi/2EAR(2))/F (L), where F (L) is the effective thickness of the flight layer where the insect searches. F (L) was estimated from catches of insects (42 species in the orders Coleoptera, Lepidoptera, Diptera, Hemiptera, and Thysanoptera) on traps at various heights as reported in the literature. The EAR(c) was proposed further as a simple but equivalent alternative to simulations of highly complex active-space plumes with variable response surfaces that have proven exceedingly difficult to quantify in nature. This hypothesis was explored in simulations where flying insects, represented as coordinate points, moved about in a correlated random walk in an area that contained a pheromone plume, represented as a sector of active space composed of a capture probability surface of variable complexity. In this plume model, catch was monitored at a constant density of flying insects and then compared to simulations in which a circular EAR(c) was enlarged until an equivalent rate was caught. This demonstrated that there is a
Lensing Constraints on the Mass Profile Shape and the Splashback Radius of Galaxy Clusters
Umetsu, Keiichi; Diemer, Benedikt
2017-02-01
The lensing signal around galaxy clusters can, in principle, be used to test detailed predictions for their average mass profile from numerical simulations. However, the intrinsic shape of the profiles can be smeared out when a sample that spans a wide range of cluster masses is averaged in physical length units. This effect especially conceals rapid changes in gradient such as the steep drop associated with the splashback radius, a sharp edge corresponding to the outermost caustic in accreting halos. We optimize the extraction of such local features by scaling individual halo profiles to a number of spherical overdensity radii, and apply this method to 16 X-ray-selected, high-mass clusters targeted in the Cluster Lensing And Supernova survey with Hubble. By forward-modeling the weak- and strong-lensing data presented by Umetsu et al., we show that, regardless of the scaling overdensity, the projected ensemble density profile is remarkably well described by a Navarro-Frenk-White (NFW) or Einasto profile out to R˜ 2.5 {h}-1 {Mpc}, beyond which the profiles flatten. We constrain the NFW concentration to {c}200{{c}}=3.66+/- 0.11 at {M}200{{c}}≃ 1.0× {10}15 {h}-1 {M}⊙ , consistent with and improved from previous work that used conventionally stacked lensing profiles, and in excellent agreement with theoretical expectations. Assuming the profile form of Diemer & Kravtsov and generic priors calibrated from numerical simulations, we place a lower limit on the splashback radius of the cluster halos, if it exists, of {R}{sp}3{{D}}/{r}200{{m}}> 0.89 ({R}{sp}3{{D}}> 1.83 {h}-1 {Mpc}) at 68% confidence. The corresponding density feature is most pronounced when the cluster profiles are scaled by {r}200{{m}}, and smeared out when scaled to higher overdensities. Based in part on data collected at the Subaru Telescope, which is operated by the National Astronomical Society of Japan.
International Nuclear Information System (INIS)
Trukhanov, G.Ya.
2005-01-01
Time-dependent neutron transport theory of G.Ya. Trukhanov and S.A. Podosenov is developed. Errors of calculating of power series expansion coefficients, γ k , in this theory were estimated. It has been found that power series convergence radius R=|χ 1,2 |= 0.9595. Power series convergence speed were estimated [ru
Pathologic fracture of the distal radius in a 25-year-old patient with a large unicameral bone cyst.
Massen, Felix; Baumbach, Sebastian; Volkmer, Elias; Mutschler, Wolf; Grote, Stefan
2014-06-13
Distal radius fractures (DRF) are often referred to as osteoporosis indicator fractures as their incidence increases from age 45. In the group of young adults, distal radius fractures normally result from high-energy trauma. Wrist fractures in young patients without adequate trauma thus raise suspicion of a pathologic fracture. In this report we present the case of a fractured unicameral bone cyst (UBC) at the distal radius in a young adult.To the author's best knowledge, this is the first detailed report in an UBC at the distal radius causing a pathologic DRF in an adult patient. A 25-year-old otherwise healthy male presented to our Emergency Department after a simple fall on his right outstretched hand. Extended diagnostics revealed a pathologic, dorsally displaced, intra-articular distal radius fracture secondary to a unicameral bone cyst occupying almost the whole metaphysis of the distal radius. To stabilize the fracture, a combined dorsal and volar approach was used for open reduction and internal fixation. A tissue specimen for histopathological examination was gathered and the lesion was filled with an autologous bone graft harvested from the ipsilateral femur using a reamer-irrigator-aspirator (RIA) system. Following one revision surgery due to an intra-articular step-off, the patient recovered without further complications. Pathologic fractures in young patients caused by unicameral bone cysts require extended diagnostics and adequate treatment. A single step surgical treatment is reasonable if fracture and bone cyst are treated appropriately. Arthroscopically assisted fracture repair may be considered in intra-articular fractures or whenever co-pathologies of the carpus are suspected.
International Nuclear Information System (INIS)
Garg, V.K.
2013-01-01
This study was planned to have a demographic survey of the households living within 30 km radius of the proposed site. Objectives of the present study were to attain the quantitative baseline demographic data around (within 30 km radius) the proposed site of nuclear power plant, zone-wise and sector-wise distribution of the population around proposed site up to a distance of 30 km from the site, to obtain the data on socio-economic, cultural, and religious perspectives of the target populations, to obtain the data on disease/illness pattern in the target population, health status and mortality rate
International Nuclear Information System (INIS)
Kinase, Sakae; Sato, Satoshi; Saito, Kimiaki; Takahashi, Tomoyuki; Sakamoto, Ryuichi
2014-01-01
Preliminary prediction models have been studied for the radioactive caesium distribution within the 80-km radius of the Fukushima Daiichi nuclear power plant. The models were represented by exponential functions using ecological half-life of radioactive caesium in the environment. The ecological half-lives were derived from the changes in ambient dose equivalent rates through vehicle-borne surveys. It was found that the ecological half-lives of radioactive caesium were not constant within the 80-km radius of the Fukushima Daiichi nuclear power plant. The ecological half-life of radioactive caesium in forest areas was found to be much larger than that in urban and water areas. (authors)
Fleurbaey, Hélène; Galtier, Sandrine; Thomas, Simon; Bonnaud, Marie; Julien, Lucile; Biraben, François; Nez, François; Abgrall, Michel; Guéna, Jocelyne
2018-05-01
We present a new measurement of the 1 S -3 S two-photon transition frequency of hydrogen, realized with a continuous-wave excitation laser at 205 nm on a room-temperature atomic beam, with a relative uncertainty of 9 ×10-13. The proton charge radius deduced from this measurement, rp=0.877 (13 ) fm , is in very good agreement with the current CODATA-recommended value. This result contributes to the ongoing search to solve the proton charge radius puzzle, which arose from a discrepancy between the CODATA value and a more precise determination of rp from muonic hydrogen spectroscopy.
Tang, Chris Yuk Kwan; Fung, Boris; Poon, T L; Fok, Margaret
2014-01-01
Even with the invention of locking plates, intra-articular fractures of distal radius with extreme comminution remain a challenge for orthopaedic surgeons. Osteochondral graft is a potential choice to reconstruct the articular defect. We report a patient who had a fracture of distal radius with costo-osteochondral graft for articular reconstruction which has not yet been described in the English literature. At nine-year follow-up, he was pain free and had full range of movement of the wrist. The authors suggest that costo-osteochondral graft could be an option with satisfactory result.
Loring, FH
2014-01-01
Summarising the most novel facts and theories which were coming into prominence at the time, particularly those which had not yet been incorporated into standard textbooks, this important work was first published in 1921. The subjects treated cover a wide range of research that was being conducted into the atom, and include Quantum Theory, the Bohr Theory, the Sommerfield extension of Bohr's work, the Octet Theory and Isotopes, as well as Ionisation Potentials and Solar Phenomena. Because much of the material of Atomic Theories lies on the boundary between experimentally verified fact and spec
Harris, Tina
2015-04-29
Grounded theory is a popular research approach in health care and the social sciences. This article provides a description of grounded theory methodology and its key components, using examples from published studies to demonstrate practical application. It aims to demystify grounded theory for novice nurse researchers, by explaining what it is, when to use it, why they would want to use it and how to use it. It should enable nurse researchers to decide if grounded theory is an appropriate approach for their research, and to determine the quality of any grounded theory research they read.
Number theory via Representation theory
Indian Academy of Sciences (India)
2014-11-09
Number theory via Representation theory. Eknath Ghate. November 9, 2014. Eightieth Annual Meeting, Chennai. Indian Academy of Sciences1. 1. This is a non-technical 20 minute talk intended for a general Academy audience.
Theory of radiation pressure on magneto–dielectric materials
International Nuclear Information System (INIS)
Barnett, Stephen M; Loudon, Rodney
2015-01-01
We present a classical linear response theory for a magneto–dielectric material and determine the polariton dispersion relations. The electromagnetic field fluctuation spectra are obtained and polariton sum rules for their optical parameters are presented. The electromagnetic field for systems with multiple polariton branches is quantized in three dimensions and field operators are converted to 1–dimensional forms appropriate for parallel light beams. We show that the field–operator commutation relations agree with previous calculations that ignored polariton effects. The Abraham (kinetic) and Minkowski (canonical) momentum operators are introduced and their corresponding single–photon momenta are identified. The commutation relations of these and of their angular analogues support the identification, in particular, of the Minkowski momentum with the canonical momentum of the light. We exploit the Heaviside–Larmor symmetry of Maxwell’s equations to obtain, very directly, the Einsetin–Laub force density for action on a magneto–dielectric. The surface and bulk contributions to the radiation pressure are calculated for the passage of an optical pulse into a semi–infinite sample. (paper)
International Nuclear Information System (INIS)
Schwarz, J.H.
1985-01-01
Dual string theories, initially developed as phenomenological models of hadrons, now appear more promising as candidates for a unified theory of fundamental interactions. Type I superstring theory (SST I), is a ten-dimensional theory of interacting open and closed strings, with one supersymmetry, that is free from ghosts and tachyons. It requires that an SO(eta) or Sp(2eta) gauge group be used. A light-cone-gauge string action with space-time supersymmetry automatically incorporates the superstring restrictions and leads to the discovery of type II superstring theory (SST II). SST II is an interacting theory of closed strings only, with two D=10 supersymmetries, that is also free from ghosts and tachyons. By taking six of the spatial dimensions to form a compact space, it becomes possible to reconcile the models with our four-dimensional perception of spacetime and to define low-energy limits in which SST I reduces to N=4, D=4 super Yang-Mills theory and SST II reduces to N=8, D=4 supergravity theory. The superstring theories can be described by a light-cone-gauge action principle based on fields that are functionals of string coordinates. With this formalism any physical quantity should be calculable. There is some evidence that, unlike any conventional field theory, the superstring theories provide perturbatively renormalizable (SST I) or finite (SST II) unifications of gravity with other interactions
Effect of Bend Radius on Magnitude and Location of Erosion in S-Bend
Directory of Open Access Journals (Sweden)
Quamrul H. Mazumder
2015-01-01
Full Text Available Solid particle erosion is a mechanical process that removes material by the impact of solid particles entrained in the flow. Erosion is a leading cause of failure of oil and gas pipelines and fittings in fluid handling industries. Different approaches have been used to control or minimize damage caused by erosion in particulated gas-solid or liquid-solid flows. S-bend geometry is widely used in different fluid handling equipment that may be susceptible to erosion damage. The results of a computational fluid dynamic (CFD simulation of diluted gas-solid and liquid-solid flows in an S-bend are presented in this paper. In addition to particle impact velocity, the bend radius may have significant influence on the magnitude and the location of erosion. CFD analysis was performed at three different air velocities (15.24 m/s–45.72 m/s and three different water velocities (0.1 m/s–10 m/s with entrained solid particles. The particle sizes used in the analysis range between 50 and 300 microns. Maximum erosion was observed in water with 10 m/s, 250-micron particle size, and a ratio of 3.5. The location of maximum erosion was observed in water with 10 m/s, 300-micron particle size, and a ratio of 3.5. Comparison of CFD results with available literature data showed reasonable and good agreement.
The radius anomaly in the planet/brown dwarf overlapping mass regime
Directory of Open Access Journals (Sweden)
Baraﬀe I.
2011-02-01
Full Text Available The recent detection of the transit of very massive substellar companions (Deleuil et al. 2008; Bouchy et al. 2010; Anderson et al. 2010; Bakos et al. 2010 provides a strong constraint to planet and brown dwarf formation and migration mechanisms. Whether these objects are brown dwarfs originating from the gravitational collapse of a dense molecular cloud that, at the same time, gave birth to the more massive stellar companion, or whether they are planets that formed through core accretion of solids in the protoplanetary disk can not always be determined unambiguously and the mechanisms responsible for their short orbital distances are not yet fully understood. In this contribution, we examine the possibility to constrain the nature of a massive substellar object from the various observables provided by the combination of Radial Velocity and Photometry measurements (e.g. Mp , Rp , M⋆, Age, a, e.... In a second part, developments in the modeling of tidal evolution at high eccentricity and inclination - as measured for HD 80 606 with e = 0.9337 (Naef et al. 2001 , XO-3 with a stellar obliquity ε⋆ > 37.3 ± 3.7 deg (Hébrard et al. 2008; Winn et al. 2009 and several other exoplanets - are discussed along with their implication in the understanding of the radius anomaly problem of extrasolar giant planets.
International Nuclear Information System (INIS)
Houlberg, W.A.; Mense, A.T.; Attenberger, S.E.
1979-09-01
Natural beam power and energy requirements are compared for full density full bore and expanding radius startup scenarios in an elongated plasma, The Next Step (TNS), as a function of beam pulse time and plasma density. Because of the similarity of parameters, the results should also be applicable to Engineering Test Facility (ETF) and International Tokamak Reactor (INTOR) studies. A transport model consisting of neoclassical ion conduction and anomalous electron conduction and diffusion based on ALCATOR scaling leads to average densities in the range approx. 0.8 to 1.2 x 10 14 cm -3 being sufficient for ignition. Neutral deuterium beam energies in the range 120 to 180 keV are adequate for penetration, with the required power injected into the plasma decreasing with increasing beam energy. The neutral beam power decreases strongly with increasing beam pulse length b/sub b/ until t/sub b/ exceeds a few total energy confinement times, yielding b/sub b/ approx. = 4 to 6 s for the TNS plasma
Le Pottier, Luc; Roy, Pryiashee; Lorenzon, Wolfgang; Raymond, Richard; Steinberg, Noah; Rossi de La Fuente, Erick; MUSE (MUon proton Scattering Experiment) Collaboration
2017-09-01
The proton radius puzzle is a currently unresolved problem which has intrigued the scientific community, dealing with a 7 σ discrepancy between the proton radii determined from muonic hydrogen spectroscopy and electron scattering measurements. The MUon Scattering Experiment (MUSE) aims to resolve this puzzle by performing the first simultaneous elastic scattering measurements of both electrons and muons on the proton, which will allow the comparison of the radii from the two interactions with reduced systematic uncertainties. The data from this experiment is expected to provide the best test of lepton universality to date. The experiment will take place at the Paul Scherrer Institute in Switzerland in 2018. An essential component of the experiment is a liquid hydrogen (LH2) cryotarget system. Our group at the University of Michigan is responsible for the design, fabrication and installation of this system. Here we present our LH2 target cell design and fabrication techniques for successful operation at 20 K and 1 atm, and our computer vision-based target position survey system which will determine the position of the target, installed inside a vacuum chamber, with 0.01 mm or better precision at the height of the liquid hydrogen target and along the beam direction during the experiment.
Inductive current startup in large tokamaks with expanding minor radius and RF assist
International Nuclear Information System (INIS)
Borowski, S.K.
1983-01-01
Auxiliary RF heating of electrons before and during the current rise phase of a large tokamak, such as the Fusion Engineering Device, is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation, 1 to 2 MW of electron cyclotron resonance heating power at approx.90 GHz is used to create a small volume of high conductivity plasma (T/sub e/ approx. = 100 eV, n/sub e/ approx. = 10 19 m -3 ) near the upper hybrid resonance (UHR) region. This plasma conditioning permits a small radius (a 0 approx.< 0.4 m) current channel to be established with a relatively low initial loop voltage (approx.< 25 V as opposed to approx.100 V without RF assist). During the subsequent plasma expansion and current ramp phase, additional RF power is introduced to reduce volt-second consumption due to plasma resistance. To study the preheating phase, a near classical particle and energy transport model is developed to estimate the electron heating efficiency in a currentless toroidal plasma. The model assumes that preferential electron heating at the UHR leads to the formation of an ambipolar sheath potential between the neutral plasma and the conducting vacuum vessel and limiter
The shaft fractures of the radius and ulna in children: current concepts.
Sinikumpu, Juha-Jaakko; Serlo, Willy
2015-05-01
The incidence of forearm shaft fractures in children has increased in recent years. They are challenging to treat and they can result in several long-lasting complications. The treatment of children's fractures needs to be individualized to their needs. Nonoperative care will be satisfactory for young, preschool children and it is primarily treatment in stable fractures of children at every age. Injury mechanism must be understood to perform appropriate closed reduction. Immobilization using a long-arm cast needs to be focused against the deforming muscle forces - in particular those that rotate - in the forearm, keeping the bones in alignment until bone healing. Operative stabilization by elastic stable intramedullary nailing is the primarily method of treatment in cases of unstable fractures, in particular, in children between preschool age and adolescence. For older children near to skeletal maturity, a rigid plate and screw fixation will be justified. The most common complication after closed treatment is worsening of the alignment and need for repetitive interventions. elastic stable intramedullary nailing results usually in good outcome, and range of forearm rotation is the main feature determining the clinical result. In this article, we report the current concept of paediatric shaft fractures in the radius and ulna.
Searches for high-mass supersymmetry using masses of large-radius jets
Heller, Ryan
2016-01-01
Results are reported from two searches for supersymmetric particles in final states with multiple jets, including several b-tagged jets, with and without large missing transverse momentum. The data sample corresponds to 2.3 fb − 1 (2.7 fb − 1 without missing transverse momentum) of pp collisions recorded by the CMS experiment at √ s = 13 TeV. The searches focus on processes with massive, high multiplicity final states, such as gluino pair production with the gluino decaying to top quarks and a neutralino, and gluino pair production with R-parity violating gluino decay to top, bottom and strange quarks. Both searches use the quantity M J , the sum of the masses of the large-radius jets, to discriminate between signal and background, establish control regions for other discriminating variables, and as a central piece of the background estimation. The observed event yields are consistent with the standard model expectations, and the results are interpreted in terms of limits on simplified supersymmetric mo...
International Nuclear Information System (INIS)
Joss, P.C.; Li, F.K.
1980-01-01
We have computed the evolution of the helium-burning shell in an accreting neutron star for various values of the stellar mass (M), radius (R), and surface magnetic fields strength (B). As shown in previous work, the helium-burning shell is often unstable and undergoes thermonuclear flashes that result in the emission of X-ray bursts from the neutron-star surface. The dependence of the properties of these bursts upon the values of M and R can be described by simple scaling relations. A strong magnetic field decreases the radiative and conductive opacities and inhibits convection in the neutron-star surface layers. For B 12 gauss, these effects are unimportant; for B> or approx. =10 13 gauss, the enhancement of the electron thermal conductivity is sufficiently large to stabilize the helium-burning shell against thermonuclear flashes. For intermediate values of B, the reduced opacities increase the recurrence intervals between bursts and the energy released per burst, while the inhibition of convection increases the burst rise times to about a few seconds. If the magnetic field funnels the accreting matter onto the magnetic polar caps, the instability of the helium-burning shell will be very strongly suppressed. These results suggest that it may eventually be possible to extract information on the macroscopic properties of neutron stars from the observed features of X-ray burst sources
Influence of edge radius of sintered-carbide tip on roughness of machined surface
Directory of Open Access Journals (Sweden)
Jiří Votava
2013-01-01
Full Text Available Increasing of cutting speed and thus increasing labour productivity is observed as a current trend in engineering production. This effort results to development of new cutting materials which are more capable to resist increased requirements on machined surface as well as operating life of the instrument. Nowadays, the most widely used materials used for cutting instruments are sintered carbides which are alloyed by other metals. The goal of this paper is to analyse change in quality of machined surface depending on the change of cutting conditions. For cutting operation, there were used a milling cutter high-speed steel 90 (HSS and removable sintered-carbide tips with different radius. Steel 12 050 hardened for 17 HRC was used as a machined material. Firstly, hardness of machined as well as machining materials was analysed. Further, metallographic analysis and measurement of microhardness of the individual structure phases was processed. Cutting conditions of both instruments were selected depending on the machined material. Surface roughness indicates the quality of machined surface.
Directory of Open Access Journals (Sweden)
Rony Baskoro Lukito
2010-12-01
Full Text Available Bina Nusantara University as one of the information technology-based educational institutions in Indonesia have used the Internet in learning activities. To meet the needs of Internet access, Binus provides students with BiNus@ccess Premium service. BiNus@ccess Premium already have an application to help admin to user management with the help of a centralized accounting system (which is provided by the RADIUS server. However, applications that use is still limited in some ways so that there are still many manual processes. Therefore we need an application that serves to replace the existing application but still supports the existing system. The methodology used to admin consists of interviews, questionnaires to users, observation to analyze the problem, designing application solutions, and evaluation by distributing questionnaires to the admin. With the RSIM applications, manual administrative processes can be eliminated because the user can perform the registration process and the addition of its own loans through the application by themselves. RSIM Applications can also provide solutions for prepaid voucher sales system because it provides the ability to generate a voucher, print vouchers, and see the voucher reports, list payment, and the sale report. Suggestions for further development is to create applications for the sale of voucher system with e-commerce or SMSgateway..