scholarly journals Using the method of integral Fourier transform to solve the problem of nonstationary deformation of an elastic medium

2019 ◽  
Vol 109 ◽  
pp. 00080
Author(s):  
Volodymyr Sapehin
Keyword(s):  
Fourier Transform ◽  
Wave Equation ◽  
Internal Pressure ◽  
Elastic Medium ◽  
Plane Deformation ◽  
Integral Fourier Transform ◽  
Nonstationary Deformation ◽  
Variable Internal Pressure ◽  
First Time

For the first time, for solving the wave equation, the method of the integral Fourier transform for an elastic medium under the action of variable internal pressure was used. This equation contains singularities of the second kind, which were excluded from the calculation by the half division method. The main parameters of the process of non-stationary deformation affecting the magnitude of stresses and displacements for the case of plane deformation are established.

Ground state molecular parameters of phosphine, PH3, from the simultaneous analysis of the high-resolution infrared, microwave and submillimeterwave spectra

1985 ◽  
Vol 50 (11) ◽  
pp. 2480-2492 ◽  
Author(s):  
Soňa Přádná ◽  
Dušan Papoušek ◽  
Jyrki Kauppinen ◽  
Sergei P. Belov ◽  
Andrei F. Krupnov ◽  
...  
Keyword(s):  
Fourier Transform ◽  
High Resolution ◽  
Ground State ◽  
Unitary Transformation ◽  
Point Of View ◽  
Acoustic Detection ◽  
Molecular Parameters ◽  
Microwave Spectrometer ◽  
Fourier Transform Spectra ◽  
First Time

Fourier transform spectra of the ν2 band of PH3 have been remeasured with 0.0045 cm-1 resolution. Ground state combination differences from these data have been fitted simultaneously with the microwave and submillimeterwave data to determine the ground state spectroscopical parameters of PH3 including the parameters of the Δk = ± 3n interactions. The correlation between the latter parameters has been discussed from the point of view of the existence of two equivalent effective rotational operators which are related by a unitary transformation. The ΔJ = 0, +1, ΔK = 0 (A1 ↔ A2, E ↔ E) rotational transitions in the ν2 and ν4 states have been measured for the first time by using a microwave spectrometer and a radiofrequency spectrometer with acoustic detection.

scholarly journals Measurements of hydrogen cyanide (HCN) and acetylene (C<sub>2</sub>H<sub>2</sub>) from the Infrared Atmospheric Sounding Interferometer (IASI)

2013 ◽  
Vol 6 (4) ◽  
pp. 917-925 ◽  
Author(s):  
V. Duflot ◽  
D. Hurtmans ◽  
L. Clarisse ◽  
Y. R'honi ◽  
C. Vigouroux ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Hydrogen Cyanide ◽  
Atmospheric Transport ◽  
Trace Gases ◽  
First Order ◽  
Line Mixing ◽  
Atmospheric Sounding ◽  
First Time ◽  
Order Comparison ◽  
Emission Ratios

Abstract. Hydrogen cyanide (HCN) and acetylene (C2H2) are ubiquitous atmospheric trace gases with medium lifetime, which are frequently used as indicators of combustion sources and as tracers for atmospheric transport and chemistry. Because of their weak infrared absorption, overlapped by the CO2 Q branch near 720 cm−1, nadir sounders have up to now failed to measure these gases routinely. Taking into account CO2 line mixing, we provide for the first time extensive measurements of HCN and C2H2 total columns at Reunion Island (21° S, 55° E) and Jungfraujoch (46° N, 8° E) in 2009–2010 using observations from the Infrared Atmospheric Sounding Interferometer (IASI). A first order comparison with local ground-based Fourier transform infraRed (FTIR) measurements has been carried out allowing tests of seasonal consistency which is reasonably captured, except for HCN at Jungfraujoch. The IASI data shows a greater tendency to high C2H2 values. We also examine a nonspecific biomass burning plume over austral Africa and show that the emission ratios with respect to CO agree with previously reported values.

scholarly journals Apparent Variation of v sin i and Rotational Modulation in Be Stars

2004 ◽  
Vol 215 ◽  
pp. 93-94
Author(s):  
C. Neiner ◽  
S. Jankov ◽  
M. Floquet ◽  
A. M. Hubert
Keyword(s):  
Fourier Transform ◽  
Magnetic Dipole ◽  
Be Stars ◽  
Line Profiles ◽  
Transform Method ◽  
Rotational Modulation ◽  
Be Star ◽  
Apparent Variation ◽  
The Fourier Transform ◽  
First Time

v sin i was determined by applying the Fourier transform method to the line profiles of two classical Be Stars. A variation is observed in the apparent v sin i which corresponds to the main frequencies associated to nrp modes. Rotational modulation is observed in wind sensitive UV lines of the Be star ω Ori and is associated with an oblique magnetic dipole which is discovered for the first time in a classical Be star.

THE WAVE EQUATIONS FOR THE WEYL TENSOR/SPINOR AND DIMENSIONALLY DEPENDENT TENSOR IDENTITIES

1996 ◽  
Vol 05 (03) ◽  
pp. 217-225 ◽  
Author(s):  
FREDRIK ANDERSSON ◽  
S. BRIAN EDGAR
Keyword(s):  
Wave Equation ◽  
Large Class ◽  
Weyl Tensor ◽  
Wave Equations ◽  
Dimensional Case ◽  
Weyl Spinor ◽  
Four Dimensions ◽  
Identity Matching ◽  
Tensor Identity ◽  
First Time

By reconciling the wave equation for the Weyl tensor with the corresponding wave equation for the Weyl spinor, we establish a new tensor identity—involving the sum of terms each consisting of a product of the Weyl and Ricci tensors—valid in four (and only four) dimensions. This enables us to give, for the first time, the correct and simplest form of the wave equation for the Weyl tensor in four-dimensional nonvacuum spacetimes. The wave equation for the Weyl tensor in n(> 4) dimensional nonvacuum spaces is also presented for the first time; we show that there does not exist an analogous n-dimensional tensor identity matching the four-dimensional one, and so it follows that there does not exist an analogous simplification of the Weyl wave equation in the n-dimensional case. It is also shown how our new identity, and some other recently discovered identities, relate to a large class of dimensionally dependent identities found some time ago by Lovelock.

On A Formulation of the Elastic Stability Equations of Circular Cylindrical Shells Under Variable Internal Pressure

1985 ◽  
Vol 9 (2) ◽  
pp. 64-69
Author(s):  
J.L. Urrutia-Galicia ◽  
A.N. Sherbourne
Keyword(s):  
Mathematical Model ◽  
Internal Pressure ◽  
Cylindrical Shells ◽  
Direct Analysis ◽  
Elastic Stability ◽  
Equilibrium Path ◽  
Circular Cylindrical Shells ◽  
The Stability ◽  
Variable Internal Pressure ◽  
The Mathematical Model

The mathematical model of the stability analysis of circular cylindrical shells under arbitrary internal pressure is presented. The paper consists of a direct analysis of the equilibrium modes in the neighbourhood of the unperturbed principal equilibrium path. The final stability condition results in a completely symmetric differential operator which is then compared with current theories found in the literature.

scholarly journals Integrated Band Intensities of Ethylene (C212H4) by Fourier Transform Infrared Spectroscopy

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
G. B. Lebron ◽  
T. L. Tan
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Ambient Temperature ◽  
Ftir Spectroscopy ◽  
Fourier Transform Infrared ◽  
Vapor Pressures ◽  
Infrared Band ◽  
Combination Bands ◽  
First Time ◽  
Absorbance Spectra

The integrated band intensities of ethylene (12C2H4) in the 640–3260 cm−1 region were determined by Fourier transform infrared (FTIR) spectroscopy. The infrared absorbance spectra of the ν7 and ν10, ν12, ν7+ν8, ν6+ν10, v11, and ν9 and ν2+ν12 bands of ethylene recorded at a resolution of 0.5 cm−1 were measured at an ambient temperature of 296 K at various vapor pressures ranging from 3×10−5 to 1×10−3 atm to obtain respective Beer-Lambert's law plots. The measured integrated band intensities in cm−1/cm atm were S(ν9andν2+ν12)=112.20±0.24, S(ν11)=55.35±0.14, S(ν12)=41.22±0.30, and S(ν7andν10)=328.66±16.55. In addition, the measured infrared band intensities of the ν7+ν8 and ν6+ν10 combination bands of ethylene are reported for the first time: S(ν7+ν8)=21.701±0.028 cm−1/cm atm and S(ν6+ν10)=2.568±0.025 cm−1/cm atm.

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