scholarly journals From Rankine-Hugoniot relation fitting procedure: Tangential discontinuity or intermediate/slow shock?

2007 ◽  
Vol 112 (A10) ◽  
pp. n/a-n/a ◽  
Author(s):  
H. Q. Feng ◽  
C. C. Lin ◽  
J. K. Chao ◽  
D. J. Wu ◽  
L. H. Lyu ◽  
...  
2008 ◽  
Vol 607 ◽  
pp. 64-66
Author(s):  
Nicolas Laforest ◽  
Jérémie De Baerdemaeker ◽  
Corine Bas ◽  
Charles Dauwe

Positron annihilation lifetime measurements on polymethylmethacrylate (PMMA) at low temperature were performed. Different discrete fitting procedures have been used to analyze the experimental data. It shows that the extracted parameters depend strongly on the fitting procedure. The physical meaning of the results is discussed. The blob model seems to give the best annihilation parameters.


2002 ◽  
Vol 09 (02) ◽  
pp. 1229-1233 ◽  
Author(s):  
S. B. WHITFIELD ◽  
R. WEHLITZ ◽  
M. O. KRAUSE ◽  
C. D. CALDWELL

Using the technique of photoelectron spectrometry in conjunction with synchrotron radiation, we have carried out a systematic study of the partial cross sections of the main photoelectron lines arising from the ionization of the 3d and 4s subshells of atomic Fe in the vicinity of 3p → 3d autoionizing resonances. Our results confirm the presence of two broad and intense resonances which have been observed earlier. However, our high resolution results also clearly indicate the presence of numerous other weaker resonances. Through a fitting procedure we were able to accurately determine both resonance widths and positions.


1997 ◽  
Vol 109 (1) ◽  
pp. 79-102 ◽  
Author(s):  
R. P. Saglia ◽  
Edmund Bertschinger ◽  
G. Baggley ◽  
David Burstein ◽  
Matthew Colless ◽  
...  
Keyword(s):  

1999 ◽  
Vol 62 (1) ◽  
pp. 117-123 ◽  
Author(s):  
S. P. TSYBENKO

A new mechanism for the formation of pinching plasma instability related to a tangential discontinuity is discussed. With this in mind we use a simple model of the Davydov–Zakharov class. It appears that there is a strong dependence of the instability increment on current density, resulting from the corresponding dispersion relation. Modulation of a current pulse is shown to be a possible way of stabilizing powerful discharges.


Author(s):  
V.Malathy Devi ◽  
D.Chris Benner ◽  
M.A.H. Smith ◽  
C.P. Rinsland ◽  
A.W. Mantz
Keyword(s):  

1996 ◽  
Vol 56 (2) ◽  
pp. 285-306 ◽  
Author(s):  
M. S. Ruderman ◽  
E. Verwichte ◽  
R. Erdélyi ◽  
M. Goossens

The stability of the MHD tangential discontinuity is studied in compressible plasmas in the presence of anisotropic viscosity and thermal conductivity. The general dispersion equation is derived, and solutions to this dispersion equation and stability criteria are obtained for the limiting cases of incompressible and cold plasmas. In these two limiting cases the effect of thermal conductivity vanishes, and the solutions are only influenced by viscosity. The stability criteria for viscous plasmas are compared with those for ideal plasmas, where stability is determined by the Kelvin—Helmholtz velocity VKH as a threshold for the difference in the equilibrium velocities. Viscosity turns out to have a destabilizing influence when the viscosity coefficient takes different values at the two sides of the discontinuity. Viscosity lowers the threshold velocity V below the ideal Kelvin—Helmholtz velocity VKH, so that there is a range of velocities between V and VKH where the overstability is of a dissipative nature.


2009 ◽  
Vol 147-149 ◽  
pp. 606-611
Author(s):  
Adam Kotowski

The paper presents the use of the autocorrelation function for the description of vibrations and the problems connected with. The proposed method is based on the analysis of vibration signal recorded for machine during its operations using an analytic form of the autocorrelation function. The parameters are obtained using a curve fitting procedure. To keep a quality of parametric representation of considered vibration, only the curve fitting causes a determination coefficient over 0.90 is taken into consideration. Therefore, the autocorrelation functions are submitted for the fast Fourier transform to be helped, in determination of number of the dominant harmonic components. Also, the analytic form and parameters of power spectral density has been also calculated. Finally, the set of parameters has been collected to describe the selected fragment of vibration of the simple rotating machine. The influence of duration of analyzed vibration on the parameters values is also examined in this work.


1990 ◽  
Vol 12 (1-3) ◽  
pp. 175-185 ◽  
Author(s):  
Kei Sakata ◽  
Dominique Daniel ◽  
John J. Jonas

In an earlier paper (Sakata et al., 1989), it was shown that the 4th and 6th order ODF coefficients could be successfully derived from Young's modulus measurements using the elastic energy method. However, the values of some of the coefficients fell beyond the expected error ranges. In this study, more appropriate single crystal elastic constants are selected by means of a fitting procedure. Then the ODF coefficients are again estimated in the manner described previously. As a result, the values of the C411, C611, C612 and C614 coeffioents, which were somewhat inaccurate in the previous calculation, are improved considerably. The volume fractions of the principal preferred orientations are then employed to predict the 8th order coefficients and the fiber components of the l = 10 and l = 12 (C1011, C1211 and C1221) coefficients. With the aid of the coefficients obtained in this way, both pole and inverse pole figures are drawn, which are in better agreement with those based on X-rays than when only the 4th order coefficients are employed.


2021 ◽  
Author(s):  
MICHAEL N. OLAYA ◽  
SAGAR PATIL ◽  
GREGORY M. ODEGARD ◽  
MARIANNA MAIARÙ

A novel approach for characterization of thermosetting epoxy resins as a function of the degree of cure is presented. Density, cure kinetics, tensile strength, and Young’s modulus are experimentally characterized across four mixing ratios of DGEBF/DETDA epoxy. Dynamic differential scanning calorimetry (DSC) is used to characterize parameters for a Prout-Thompkins kinetic model unique to each mixing ratio case through a data fitting procedure. Tensile strength and Young’s modulus are then characterized using stress-strain data extracted from quasi-static, uniaxial tension tests at room temperature. Strains are measured with the 2-D digital image correlation (DIC) optical strain measurement technique. Strength tends to increase as amine content use in the formulation increases. The converse trend is observed for Young’s modulus. Density measurements also reveal an inverse relationship with amine content.


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