Über die Verschiebung zylindrischer Lichtbögen ohne Materiebewegung

1968 ◽  
Vol 23 (3) ◽  
pp. 424-432
Author(s):  
Jürgen Raeder
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Steady State ◽  
Gas Flow ◽  
Space Variable ◽  
Electric Arc ◽  
Explicit Dependence ◽  
Heating And Cooling ◽  
Theoretical Results ◽  
Good Agreement

An electric arc may be displaced by a magnetic field, by a gas flow and also by unsymmetric heating and cooling. This occurs for instance, if a portion of the wall of a wall-stabilized arc is heated. For this case the displacement is investigated theoretically for steady state conditions. Furthermore the deflection is calculated for an explicit dependence of electrical and thermal conductivity upon a space variable. The different possibilities considered in theory are realized experimentally. The measurements are in good agreement with the theoretical results.

Anomalous Heat Conduction, Diffusion and Heat Rectification in Nanoscale Structures

2009 ◽  
Author(s):  
Gang Zhang ◽  
Nuo Yang ◽  
Gang Wu ◽  
Baowen Li
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Heat Transport ◽  
Nano Materials ◽  
Fourier Law ◽  
Nanoscale Structures ◽  
Recent Developments ◽  
Theoretical Results ◽  
Good Agreement ◽  
Anomalous Heat

In this paper, we report the recent developments in the study of heat transport in nano materials. First of all, we show that phonon transports in nanotube super-diffusively which leads to a length dependence thermal conductivity, thus breaks down the Fourier law. Then we discuss how the introduction of isotope doping can reduce the thermal conductivity efficiently. The theoretical results are in good agreement with experimental ones. Finally, we will demonstrate that nanoscale structures are promising candidates for heat rectification.

IONOSPHERIC REFLECTION OF VERY LONG RADIO WAVES

1950 ◽  
Vol 28a (6) ◽  
pp. 549-557 ◽  
Author(s):  
J. P. Stanley
Keyword(s):  
Magnetic Field ◽  
Reflection Coefficient ◽  
Wave Reflection ◽  
Simplified Model ◽  
Angle Of Incidence ◽  
Vertical Magnetic Field ◽  
Radio Waves ◽  
Long Wave ◽  
Theoretical Results ◽  
Good Agreement

A simplified model of the long-wave-reflecting region of the ionosphere, first considered in a previous paper, is used to calculate the theoretical variation of sky wave reflection coefficient with angle of incidence and with the angle of dip of the earth's magnetic field. The resulting curves are found to be in good agreement with experiment. They lead to the conclusion that theoretical results based on the assumption of a vertical magnetic field will not lead to errors in vertical incidence sky wave reflection coefficient greater than about 10%, even though the field is inclined at an angle of as much as 23° to the vertical.

scholarly journals Experimental Investigation of a Magnetically Balanced Arc in a Transverse Argon Flow

1966 ◽  
Vol 88 (1) ◽  
pp. 27-30 ◽  
Author(s):  
T. W. Myers ◽  
C. N. McKinnon ◽  
J. C. Lysen
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Atmospheric Pressure ◽  
Gas Flow ◽  
Electric Arc ◽  
Test Apparatus ◽  
Gas Velocity ◽  
Argon Gas ◽  
Argon Flow ◽  
Arc Current

An experimental study of an electric arc in crossed convective and magnetic fields has been made. An electric arc was established across a rectangular test section through which argon gas was flowing at approximately atmospheric pressure and velocities up to 100 m/sec. Magnetic field strengths up to 3 webers/m2, oriented so that the Lorentz force opposed the convective force on the arc, were applied perpendicular to both the arc and the direction of the argon gas flow. The test apparatus and the procedure used to obtain the experimental relationship between the velocity of the argon flow and the balancing magnetic field are described. An analysis which assumed the magnetically balanced arc to be a gaseous cylinder positioned between the electrodes and with a diameter varying directly as the arc current satisfactorily explained the observed dependence of the balancing magnetic field on the gas velocity.

A MODEL FOR PREDICTING THE EFFECTIVE THERMAL CONDUCTIVITY OF NANOPARTICLE-FLUID SUSPENSIONS

2006 ◽  
Vol 05 (01) ◽  
pp. 23-33 ◽  
Author(s):  
S. M. S. MURSHED ◽  
K. C. LEONG ◽  
C. YANG
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Body Centered Cubic ◽  
Geometrical Structures ◽  
New Model ◽  
Water Based ◽  
Classical Models ◽  
Theoretical Results ◽  
Enhanced Thermal Conductivity ◽  
Good Agreement

The uniformity and homogeneously dispersed nanoparticles in base fluids contribute to enhanced thermal conductivity of the mixture. By considering the uniformity and geometrical structures (e.g., body-centered cubic) of homogeneously dispersed nanoparticles in base fluids, a model for determining the effective thermal conductivity (ETC) of such nanoparticle-fluid suspensions, commonly known as nanofluids is proposed in this study. The theoretical results of the effective thermal conductivities of TiO 2/Deionized (DI) water and Al 2 O 3/DI water-based nanofluids are presented, and they are found to be in good agreement with our experimental results and also with those reported in the literature. The new model presented in this study shows a better prediction of the effective thermal conductivity of nanofluids compared to other classical models attributed to Maxwell, Hamilton–Crosser, and Bruggeman.

scholarly journals Particle-in-cell simulations of electron spin effects in plasmas

2013 ◽  
Vol 79 (4) ◽  
pp. 377-382 ◽  
Author(s):  
GERT BRODIN ◽  
AMOL HOLKUNDKAR ◽  
MATTIAS MARKLUND
Keyword(s):  
Magnetic Field ◽  
Magnetic Dipole ◽  
Electron Spin ◽  
Electromagnetic Pulse ◽  
Particle In Cell ◽  
Spin Effects ◽  
Dipole Force ◽  
The Magnetic Field ◽  
Theoretical Results ◽  
Good Agreement

AbstractWe present a particle-in-cell code accounting for the magnetic dipole force and for the magnetization currents associated with the electron spin. The electrons are divided into spin-up and spin-down populations relative to the magnetic field, where the magnetic dipole force acts in opposite directions for the two species. To validate the code, we study wakefield generation by an electromagnetic pulse propagating parallel to an external magnetic field. The properties of the generated wakefield are shown to be in good agreement with previous theoretical results. Generalizations of the code to account for other quantum effects are discussed.

scholarly journals Some theoretical model for determining the temperature field of a multi-disk brake

2020 ◽  
Vol 12 (1) ◽  
pp. 168781402090232
Author(s):  
Aleksander Yevtushenko ◽  
Michal Kuciej ◽  
Katarzyna Topczewska
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Carbon Composite ◽  
Temperature Level ◽  
Disk Brake ◽  
Carbon Composite Material ◽  
Single Disk ◽  
Analytical Formulae ◽  
Theoretical Results ◽  
Good Agreement

Analytical formulae were obtained to quickly determine the temperature level in a single disk of the multi-disk brake. They take into account the time of contact pressure increase, convective cooling on lateral surfaces of the disk, and different thermal conductivity of material in the axial and radial directions. Calculations were performed for a disk made of carbon composite material Termar-ADF. The influence of the aforementioned input parameters on the temperature of the disk during single braking was studied. It is established that the obtained theoretical results are in good agreement with the corresponding experimental data.

The Effect of Spin Dependent Scattering from Impurities on Giant Magnetoresistance and Thermal Conductivity in Fe/Cr Multilayers

1991 ◽  
Vol 231 ◽  
Author(s):  
B.L. Johnson ◽  
R.E. Camley
Keyword(s):  
Magnetic Field ◽  
Thermal Conductivity ◽  
Low Temperature ◽  
Thermal Effects ◽  
Giant Magnetoresistance ◽  
Boltzmann Transport Equation ◽  
Equation Approach ◽  
Boltzmann Transport ◽  
Spin Dependent Scattering ◽  
Good Agreement

AbstractRecent experiments have tested the assumption that a spin-dependent asymmetry in scattering is responsible for the giant magnetoresistance (GMR) in Fe/Cr multilayers by introducing additional impurities (with different spin-dependent scattering asymmetries) at the interfaces. This paper presents a theoretical calculation based on a Boltzmann transport equation approach which is appropriate for these new experiments. We find that when impurities (Mn, V) are introduced which have a spin-dependent scattering asymmetry similar to that of Cr in Fe the GMR is not substantially changed. When impurities (Al, Ir) with a spin-dependent scattering asymmetry opposite to that of Cr in Fe are introduced there is a rapid degredation of the GMR. Our results are compared with experiment and good agreement is found provided that the magnitude of the scattering asymmetry in Al is reduced somewhat from low-temperature published values. It is argued that thermal effects could indeed provide such a reduction. We also point out that the thermal conductivity should undergo changes with magnetic field in these structures, since the thermal conductivity also depends upon electron mobility.

Sign in / Sign up

Export Citation Format

Share Document