298 research outputs found
Generation of a North/South Magnetic Field Component from Variations in the Photospheric Magnetic Field
We address the problem of calculating the transverse magnetic field in the
solar wind outside of the hypothetical sphere called the source surface where
the solar wind originates. This calculation must overcome a widely used
fundamental assumption about the source surface -- the field is normally
required to purely radial at the source surface. Our model rests on the fact
that a change in the radial field strength at the source surface is a change in
the field line density. Surrounding field lines must move laterally in order to
accommodate this field line density change. As the outward wind velocity drags
field lines past the source surface this lateral component of motion produces a
tilt implying there is a transverse component to the field.
An analytic method of calculating the lateral translation speed of the field
lines is developed. We apply the technique to an interval of approximately two
Carrington rotations at the beginning of 2011 using 2-h averages of data from
the Helioseismic Magnetic Imager instrument on the Solar Dynamics Observatory
spacecraft. We find that the value of the transverse magnetic field is
dominated on a global scale by the effects of high latitude concentrations of
field lines being buffetted by supergranular motions.Comment: 23 pages with 8 figures. Accepted by Solar Physics (LaTeX processing
with aastex6.cls instead of solarphysics.cls due to compatibility issues
OPTIMAL PLACEMENT AND ACTIVE VIBRATION CONTROL OF COMPOSITE PLATES INTEGRATED PIEZOELECTRIC SENSOR/ACTUATOR PAIRS
In this study, a finite element model based on first-order shear deformation theory is presented for optimal placement and active vibration control of laminated composite plates with bonded distributed piezoelectric sensor/actuator pairs. The model employs the nine-node isoparametric rectangular element with 5 degrees of freedom for the mechanical displacements, and 2 electrical degrees of freedom. Genetic algorithm (GA) is applied to maximize the fundamental natural frequencies of plates; and the constant feedback control method is used for the vibration control analysis of piezoelectric laminated composite plates. The results of this study can be used to aid the placement of piezoelectric sensor/actuator pairs of smart composite plates as well as for robust controller design
Photospheric Velocities Measured at Mt. Wilson Show Zonal and Sectoral Flows Compose the Torsional Oscillations
The methods for reducing the observations from the 150-foot Tower Telescope
on Mt.~Wilson are reviewed and a new method for determining the North/South
(sectoral) and the East/West (zonal) velocity components is described and
applied. Due to a calibration problem with the data prior to 1983, only
observations between 1983 and 2013 are presented at this time. After
subtraction of latitude dependent averages over the 30-year period of
observation the residual deviations in the sectoral and zonal flow velocities
are well synchronized and correspond to what is widely recognized as the
Torsional Oscillations. Both flow components need to be included in any model
that replicates the Torsional Oscillations.Comment: 15 pages, 5 figures, 1 table. Submitted to Solar Physics 7/12/202
Anomalous Magnetic Dipole Moment in 3-3-1 Model with Inverse Seesaw Neutrinos
We will show that the recent experimental value of the anomalous magnetic moment (AMM) of the charged lepton m , denoted as , can be explained successfully in a 3-3-1 model with right handed neutrino adding new heavy neutrinos singlets. Allowed regions satisfying the recent AMM data are illustrated numerically
A Study on Derailment at Railway Turnout Using the Multi-body Dynamics Simulation
In this study, the locomotive and the turnout were simulated with three-dimensional models. The purpose of this study is prediction the derailment phenomenon of the locomotive running on the turnout in Vietnam. Multi-body simulations were implemented by SIMPACK software to determine the derailment coefficient, the wheel unloading factor, and the lateral force. The interaction between the locomotive and the track structure at turnout was considered unified. The derailment coefficient, the wheel unloading factor, and the lateral force were calculated for locomotive-D19E at turnout (tg0.15) for 1000 mm gauge according to QCVN 18:2011/BGTVT, EN 14363:2016, and TCVN 8784:2011. The derailment coefficient, the wheel unloading factor, and the lateral force for the locomotive at max speed V=27.8 km/h are 0.94, 0.61, and 67.46 kN, respectively. These results show that the locomotive will not derail when it passes the turnout at a speed V 27.8 km/h
A Study on Derailment at Railway Turnout Using the Multi-body Dynamics Simulation
In this study, the locomotive and the turnout were simulated with three-dimensional models. The purpose of this study is prediction the derailment phenomenon of the locomotive running on the turnout in Vietnam. Multi-body simulations were implemented by SIMPACK software to determine the derailment coefficient, the wheel unloading factor, and the lateral force. The interaction between the locomotive and the track structure at turnout was considered unified. The derailment coefficient, the wheel unloading factor, and the lateral force were calculated for locomotive-D19E at turnout (tg0.15) for 1000 mm gauge according to QCVN 18:2011/BGTVT, EN 14363:2016, and TCVN 8784:2011. The derailment coefficient, the wheel unloading factor, and the lateral force for the locomotive at max speed V=27.8 km/h are 0.94, 0.61, and 67.46 kN, respectively. These results show that the locomotive will not derail when it passes the turnout at a speed V 27.8 km/h
Axion in a 3-3-1 Model with Right-handed Neutrinos
We  show that Peccei - Quinn(PQ) symmetry can be a natural outcomein the 3-3-1 model with right neutrinos after imposing a symmetry. This symmetry is suitableaccommodated in this model when we augmented its spectrum byincluding a singlet scalar field with large VEV. After breakingthe PQ symmetry yielding the axion we study the decay of axioninto two photons. The result shows that the lifetime of axion isvery long, therefore the axion can play the role of the latedecaying particle(LDP) in a dark matter and it is stable in ouruniverse
Production Cross Sections of Axion in a Static Electromagnetic Field
Photon - axion conversions in staticelectromagnetic fields of the size areconsidered in detail by the Feynman diagram methods. Thedifferential cross sections are presented and the numericalevaluations of the total cross section are given. Our result showsthat the conversion cross-sections in the electric field are quitesmall, while in the strong magnetic field, the cross-sections are much enhanced, which can be measurable in current experiments.Photon - axion conversions in staticelectromagnetic fields of the size areconsidered in detail by the Feynman diagram methods. The differential cross sections are presented and the numerical evaluations of the total cross section are given. Our result shows that the conversion cross-sections in the electric field are quite small, while in the strong magnetic field, the cross-sections are much enhanced, which can be measurable in current experiments
PREPARATION AND FTIR STUDIES OF PMMA/PVC POLYMER BLENDS, PVC-g-PMMA GRAFT COPOLYMERS AND EVALUATING GRAFT CONTENT
This study presents the qualitative and quantitative analyses of Fourier Transform Infrared (FTIR) spectra of poly(methyl methacrylate)/poly(vinyl chloride) blends (PMMA/PVC), as well as PVC-g-PMMA graft copolymers. Graft copolymerizations of methyl mathacrylate (MMA) onto PVC macromolecules were carried out mixture of cyclohexanone/N,N-dimethylformamide as solvents, dibenzoyl peroxide as initiator and nitrogen medium. FTIR spectra of PMMA/PVC blends showed that there were molecular interactions between C=O groups of PMMA and C-Cl groups of PVC. Assignments of infrared absorption bands for specific groups of PMMA/PVC blends have been contributed. Using regression method, linear calibration curve between PMMA mole content and peak areas of C=O groups in FTIR spectra of the blends has been found when C=O peak areas were multiplied by an appropriate factor. PMMA grafted content and total PMMA formed content in PVC-g-PMMA graft copolymers have been evaluated. The results showed that grafted PMMA content was increased since PVC was initiatly dechlorinated by NaOH solution. The grafted PMMA content and total formed PMMA content were 5.05 wt.% and 11.25 wt.% respectively when MMA monomers were grafted onto neat PVC and modified PVC molecules
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