Radiation Power of He–Ne Laser with Different Geometry of the Tube Cross Section

Author(s):  
Vadim Kozhevnikov ◽  
Vadim Privalov ◽  
Valery Shemanin
2018 ◽  
Vol 7 (3.19) ◽  
pp. 92
Author(s):  
Sveshnikov V.K ◽  
Bazarkin A.F ◽  
Kurenschikov A.V

They consider the calculation technique for the resonance radiation power of a direct low-pressure sodium lamp with a sickle-shaped discharge tube cross-section. The calculation of the sodium discharge radiation power is difficult in such a tube, as compared with the calculation in a cylindrical shape tube. The dependence of the relative output of sodium discharge resonant radiation occurring in equivalent discharge tubes in the form of a parallelepiped and a cylinder is based on the involvement of the theory by M. Cayless. The obtained results were used to determine the power of DNaO-85M lamp resonant radiation. They presented the scheme of the device to study the influence of the tube geometry on sodium discharge power. It is shown that the power of the resonance radiation generated by an equivalent discharge will be the greater, the larger the cross section of the discharge tube. The discrepancy between the calculated and the experimental data for resonant radiation power determination in a crescent-shaped tube is less than 4%.  


1989 ◽  
Vol 104 (1) ◽  
pp. 449-456
Author(s):  
V. V. Zheleznyakov ◽  
E. Ya. Zlotnik

AbstractIt was shown by Zheleznyakov and Zlotnik (1980a, b) that in complex configurations of solar magnetic fields (in hot loops above the active centres, in neutral current sheets in the preflare phase, in hot X-ray kernels in the initial flare phase) a system of cyclotron lines in the spectrum of microwave radiation is likely to be formed. Such a line was obtained by Willson (1985) in the VLA observations at harmonics of the electron gyrofrequency. This communication interprets these observations on the basis of an active region model in which thermal cyclotron radiation is produced by hot plasma filling the magnetic tube in the corona above a group of spots. In this model the frequency of the recorded 1658 MHz line corresponds to the third harmonic of electron gyrofrequency, which yields the magnetic field (196 + 4) G along the magnetic tube axis. The linewidth Af/f ∼ 0.1 is determined by the 10% inhomogeneity of the magnetic field over the cross-section of the tube; the line profile indicates the kinetic temperature distribution of electrons over the tube cross-section with the maximum value 4 x 106 K. Analysis shows that study of cyclotron lines can serve as an efficient tool for diagnostics of magnetic fields and plasma in the solar active regions and flares.


2016 ◽  
Vol 61 (3) ◽  
pp. 1655-1662
Author(s):  
J. Michalczyk ◽  
M. Nabiałek ◽  
M. Szota

Abstract The paper presents the results of numerical studies based on a mathematical model determined by the stress-strain state examination method. Numerical computations for two steel grades, namely H40 and C45, were made at similar strain and process rate parameters. As a result of the studies, the distribution of elastic and plastic zones was obtained, while the tube hollow drawing force was verified experimentally. The distribution of longitudinal, radial and circumferential stresses and, after the drawing operation, the distribution of residual stresses in the tube cross-section were also obtained.


1949 ◽  
Vol 53 (467) ◽  
pp. 1041-1052 ◽  
Author(s):  
D. J. Farrar

The primary structure of an aeroplane usually consists basically of a set of tubular beams. The main structural box of the wing or tailplane is a well-known example: a semi-monocoque fuselage is another. For any given loading condition of the aircraft the material in the tube is stressed mainly in tension, in shear, or in compression, depending on its location in the tube cross section.The aim of the designer is to make the material fulfil these three functions in the most economical manner. In tension, he is limited only by the quality of material available. In shear, this is again substantially the case, although it is well known that very light shear webs over great depths do not develop as high an effective failing stress as do more sturdy webs. This property of dependence on theintensity of loadingis much more marked in the case of the compression structure, which is liable to instability in various ways.


2011 ◽  
Vol 462-463 ◽  
pp. 265-270
Author(s):  
Xiu Gen Jiang ◽  
Ning Xu ◽  
Xu Dong Shi ◽  
Yu Huan Wu ◽  
Xing Hua Chen ◽  
...  

The performance of the casing-plug joint, including load carrying capacity, stiffness, failure modes, and its influence factors of the casing tubes set inside and outside of the main tubes are analyzed by simulating square steel tube casing-plug joints structures with ANSYS software in this paper. The formulas of the optimum l/L for the joints with the size of the main tube cross-section 200mm× 200mm are given in this paper.


2018 ◽  
Vol 610 ◽  
pp. L9 ◽  
Author(s):  
K. Karampelas ◽  
T. Van Doorsselaere

Context. In recent years, a number of numerical studies have been focusing on the significance of the Kelvin–Helmholtz instability in the dynamics of oscillating coronal loops. This process enhances the transfer of energy into smaller scales, and has been connected with heating of coronal loops, when dissipation mechanisms, such as resistivity, are considered. However, the turbulent layer is expected near the outer regions of the loops. Therefore, the effects of wave heating are expected to be confined to the loop’s external layers, leaving their denser inner parts without a heating mechanism. Aim. In the current work we aim to study the spatial evolution of wave heating effects from a footpoint driven standing kink wave in a coronal loop. Methods. Using the MPI-AMRVAC code, we performed ideal, three dimensional magnetohydrodynamic simulations of footpoint driven transverse oscillations of a cold, straight coronal flux tube, embedded in a hotter environment. We have also constructed forward models for our simulation using the FoMo code. Results. The developed transverse wave induced Kelvin–Helmholtz (TWIKH) rolls expand throughout the tube cross-section, and cover it entirely. This turbulence significantly alters the initial density profile, leading to a fully deformed cross section. As a consequence, the resistive and viscous heating rate both increase over the entire loop cross section. The resistive heating rate takes its maximum values near the footpoints, while the viscous heating rate at the apex. Conclusions. We conclude that even a monoperiodic driver can spread wave heating over the whole loop cross section, potentially providing a heating source in the inner loop region. Despite the loop’s fully deformed structure, forward modelling still shows the structure appearing as a loop.


2012 ◽  
Vol 41 ◽  
pp. 105-114 ◽  
Author(s):  
António F.O. Falcão ◽  
José J. Cândido ◽  
Paulo A.P. Justino ◽  
João C.C. Henriques

1990 ◽  
Vol 57 (4) ◽  
pp. 969-973 ◽  
Author(s):  
S. Li ◽  
S. R. Reid

The buckling behavior of axially compressed square tubes is investigated by introducing realistic edge conditions for the panels which correspond to symmetry or antisymmetry in the modes of deformation of the tube cross-section with regard to the diagonals of the section. The results show a number of differences between the buckling behavior of square tubes and of simply-supported plates. This vanishes only for very thin tubes and plates. The comparison between the buckling mode for thinner and thicker tubes suggests an explanation for the existence of compact and noncompact crushing modes in the subsequent crushing of tubes.


2013 ◽  
Vol 315 ◽  
pp. 334-338 ◽  
Author(s):  
Jaffar S. Mohamed Ali ◽  
Kassim A. Abdullah ◽  
Yulfian Aminanda

In this study, numerical simulation of tubes of various cross section under axial compression is carried out using LS-DYNA. The effect of varying configurations of tube cross-section shape on the deformation response, collapse mode and energy absorption characteristics of tubes under quasi-static axial compression have been studied. The validation of the finite element tube model was made by comparison with the experimental results of the square tube subjected to quasi-static axial compression. Tabulated results are presented and plots have been included for the specific energy absorption for different cross sections. The study provides an insight on ways to increasing energy absorption of light weight aluminium tubes.


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