Exact Vibration Solutions of Nonhomogeneous Circular, Annular and Sector Membranes

2012 ◽  
Vol 4 (2) ◽  
pp. 250-258 ◽  
Author(s):  
Chang Yi Wang ◽  
Wang Chien Ming
Keyword(s):  
Fundamental Frequency ◽  
Power Index ◽  
Dominant Factor ◽  
Opening Angle ◽  
Circular Membrane ◽  
Vibration Frequencies ◽  
Absolute Value ◽  
Inner Radius ◽  
First Time ◽  
Annular Membrane

AbstractIn this paper, exact vibration frequencies of circular, annular and sector membranes with a radial power law density are presented for the first time. It is found that in general, the sequence of modes may not correspond to increasing az-imuthal mode number n. The normalized frequency increases with the absolute value of the power index |ν|. For a circular membrane, the fundamental frequency occurs at n = 0 where n is the number of nodal diameters. For an annular membrane, the frequency increases with respect to the inner radius b. When b is close to one, the width 1 – b is the dominant factor and the differences in frequencies are small. For a sector membrane, n – 1 is the number of internal radial nodes and the fundamental frequency occurs at n = 1. Increased opening angle β increases the frequency.

Who Did the Audit? Audit Quality and Disclosures of Other Audit Participants in PCAOB Filings

2014 ◽  
Vol 90 (5) ◽  
pp. 1939-1967 ◽  
Author(s):  
Carol Callaway Dee ◽  
Ayalew Lulseged ◽  
Tianming Zhang
Keyword(s):  
Audit Quality ◽  
Market Reaction ◽  
Audit Fees ◽  
Discretionary Accruals ◽  
Multivariate Model ◽  
Significant Decline ◽  
Earnings Response Coefficients ◽  
Absolute Value ◽  
Earnings Response ◽  
First Time

ABSTRACT We empirically test whether audit quality is affected when part of an SEC issuer's audit is outsourced to auditors other than the principal auditor (“participating auditors”). We find a significantly negative market reaction and a significant decline in earnings response coefficients (ERCs) for experimental issuers disclosed for the first time as having participating auditors involved in their audits. However, we find no market reaction and no decline in ERCs for a matching sample of issuers that are not disclosed as using participating auditors, nor for issuers disclosed for the second or third time as using participating auditors. We also find actual audit quality as measured by absolute value of performance-matched discretionary accruals is lower for the experimental issuers, although we find no difference in audit fees paid by the experimental and matching issuers in a multivariate model. Our findings suggest that the PCAOB's proposed rule requiring disclosure of the use of other auditors in addition to the principal auditor would provide information useful to investors in assessing audit quality for SEC issuers.

Static Multiaxial Fracture Behavior of Graphite Components: A Review of Recent Results

2017 ◽  
Vol 754 ◽  
pp. 35-38 ◽  
Author(s):  
S.M.J. Razavi ◽  
M. Peron ◽  
J. Torgersen ◽  
F. Berto
Keyword(s):  
Strain Energy Density ◽  
Strain Energy ◽  
Fracture Behavior ◽  
Local Strain ◽  
Opening Angle ◽  
Mode Mixity ◽  
Static Tests ◽  
Complete Set ◽  
Tip Radius ◽  
First Time

The problem of mixed mode (I+III) brittle fracture of polycrystalline graphite is investigated systematically here for the first time. The present study considers cylindrical specimens weakened by circumferential notches characterized by different acuities. A new complete set of experimental data is provided considering different geometrical configurations by varying the notch opening angle and the notch tip radius. The multiaxial static tests have been performed considering different values of the mode mixity ratio. A criterion based on the local Strain Energy Density previously applied by the same authors only to pure modes of loading is extended here to the case of tension and torsion loadings applied in combination.

Fermi Surface Study of Organic Metals (Bedt-TTF)2X

1992 ◽  
Vol 247 ◽  
Author(s):  
M. Tokumoto ◽  
A. G. Swanson ◽  
J. S. Brooks ◽  
C. C. Agosta ◽  
S. T. Hannahs ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Fundamental Frequency ◽  
Electronic System ◽  
Surface Topology ◽  
Spin Splitting ◽  
Simple Metal ◽  
Organic Metals ◽  
Fundamental Frequencies ◽  
First Time ◽  
Oscillation Characteristic

ABSTRACTObservations of Shubnikov-de Haas(SdH) and de Haas-van Alphen(dHvA) oscillations in organic metals (BEDT-TTF)2X, with X=KHg(SCN)4, θ-I3 and β″-AuBr2. are reported. In KHg(SCN)4 salt, in addition to the SdH oscillations with fundamental frequency of 670 T corresponding to about 16% of the first Brillouin zone(FBZ), we observed splitting of each SdH peak which we ascribed to “spin-splitting” We have also found that the ground state of this salt is not a simple metal but has some magnetic character. In θ-l3 salt we have succeeded in an observation of dHvA oscillations for the first time. We observed a “saw-tooth” dHvA oscillation characteristic to a highly two-dimensional and extraordinary clean electronic system. In addition to the fundamental frequency of 4170 T corresponding to 50.4 % of the FBZ and its higher harmonics, we observed an oscillation with lower frequency of 730 T corresponding to about 8.8 % of the FBZ. A new Fermi surface topology for θ-l3 salt is proposed based on the analysis of the dHvA effect. In β″-AuBr2, we observed complex dHvA oscillations, which can be explained in terms of the mixing of two fundamental frequencies of 47 and 268 T, suggesting the presence of very small pockets corresponding to 0.6 and 2.9 % of the FBZ.

Axial Impact Buckling of a Column With Random Initial Imperfections

1978 ◽  
Vol 45 (2) ◽  
pp. 361-365 ◽  
Author(s):  
I. Elishakoff
Keyword(s):  
Critical Time ◽  
Initial Imperfection ◽  
Random Variable ◽  
Axial Impact ◽  
Absolute Value ◽  
Initial Imperfections ◽  
Total Displacement ◽  
Probabilistic Setting ◽  
Probabilistic Nature ◽  
First Time

Axial impact buckling of perfectly elastic bars with initial imperfections is considered in a probabilistic setting. It is assumed that the initial imperfection function involved a single parameter, which in turn is a continuous random variable with given probability distribution function. The structure is said to buckle if the absolute value of the total displacement exceeds a prescribed value. The probabilistic nature of the random, critical time when such a failure occurs for the first time, is studied.

scholarly journals Resolving the dusty circumstellar environment of the A[e] supergiant HD 62623 with the VLTI/MIDI

2010 ◽  
Vol 6 (S272) ◽  
pp. 406-407
Author(s):  
Antony Meilland ◽  
Sameer Kanaan ◽  
Marcelo Borges Fernandes ◽  
Olivier Chesneau ◽  
Florentin Millour ◽  
...  
Keyword(s):  
Gravitational Effect ◽  
Circumstellar Envelope ◽  
Total N ◽  
Mid Infrared ◽  
Probable Case ◽  
Inner Radius ◽  
Supergiant Star ◽  
First Time ◽  
Gaseous Envelope ◽  
Circumstellar Environment

AbstractHD 62623 is one of the very few A-type supergiants showing the B[e] phenomenon. We studied the geometry of its circumstellar envelope in the mid-infrared using the VLTI/MIDI instrument. Using the radiative transfer code MC3D, we managed to model it as a dusty disk with an inner radius of 3.85 AU, an inclination angle of 60°, and a mass of 2 × 10−7M⊙. It is the first time that the dusty disk inner rim of a supergiant star exhibiting the B[e] phenomenon is significantly constrained. The inner gaseous envelope likely contributes up to 20% to the total N band flux and acts like a reprocessing disk. Finally, the hypothesis of a stellar wind deceleration by the companion gravitational effect remains the most probable case since the bi-stability mechanism is not efficient for this star.

scholarly journals Revisiting the supersymmetric Pati–Salam models from intersecting D6-branes

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Tianjun Li ◽  
Adeel Mansha ◽  
Rui Sun
Keyword(s):  
Model Building ◽  
Gauge Coupling ◽  
Type Ii ◽  
Absolute Value ◽  
Hidden Sector ◽  
Gauge Symmetries ◽  
The Standard Model ◽  
New Models ◽  
Time Construct ◽  
First Time

AbstractEmploying novel random and supervised scanning methods, we systematically revisit the construction of three-family $$N=1$$ N = 1 supersymmetric Pati–Salam models in Type IIA orientifolds on $$\mathbf{T}^6/({\mathbb {Z}}_2\times {\mathbb {Z}}_2)$$ T 6 / ( Z 2 × Z 2 ) with intersecting D6-branes. Arising from the stacks of D6-branes with U(n) gauge symmetries, the Pati–Salam gauge symmetries $$SU(4)_C\times SU(2)_L \times SU(2)_R$$ S U ( 4 ) C × S U ( 2 ) L × S U ( 2 ) R can be broken down to the Standard Model via D-brane splitting as well as D- and F-flatness preserving Higgs mechanism. Also, the hidden sector contains USp(n) branes, which are parallel with the orientifold planes or their $${{\mathbb {Z}}_2}$$ Z 2 images. We find that the Type II T-duality in the previous study is not an equivalent relation in Pati–Salam model building if the model is not invariant under $$SU(2)_L$$ S U ( 2 ) L and $$SU(2)_R$$ S U ( 2 ) R exchange, and provides a way to obtain new models. We systematically construct the new models with three families, which usually do not have gauge coupling unification at the string scale. We for the first time construct the Pati–Salam models with at least one wrapping number whose absolute value reaching 5. In particular, for one large wrapping number equal to 5, we find that one kind of model carries more refined gauge couplings, and thus with more possibilities to have approximate gauge coupling unification.

scholarly journals Incorporation of Threshold Phenomena in Three-body Coulomb Continuum Wavefunctions

1996 ◽  
Vol 49 (6) ◽  
pp. 1095 ◽  
Author(s):  
Jamal Berakdar
Keyword(s):  
Spin Asymmetry ◽  
Excess Energy ◽  
Absolute Value ◽  
Threshold Phenomena ◽  
Cusp Conditions ◽  
Wannier Threshold ◽  
Coulomb Boundary Conditions ◽  
Three Body ◽  
Energy Sharing ◽  
First Time

In this work a three-body Coulomb wavefunction for the description of two continuum electrons moving in the field of a nucleus is constructed such that the Wannier threshold law for double escape is reproduced and the asymptotic Coulomb boundary conditions as well as the Kato cusp conditions are satisfied. It is shown that the absolute value of the total cross section, as well as the spin asymmetry, are well described by the present approach. Further, the excess-energy sharing between the two escaping electrons is calculated and analysed in light of the Wannier theory predictions. This is the first time an analytical three-body wavefunction is presented which is asymptotically exact and capable of describing threshold phenomena.

scholarly journals Two Correlations with Enhancement Near the Proton Gyroradius Scale in Solar Wind Turbulence: Parker Solar Probe (PSP) and Wind Observations

2022 ◽  
Vol 924 (2) ◽  
pp. 92
Author(s):  
G. Q. Zhao ◽  
Y. Lin ◽  
X. Y. Wang ◽  
H. Q. Feng ◽  
D. J. Wu ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Energy ◽  
Data Sets ◽  
Absolute Value ◽  
Magnetic Energy Density ◽  
Solar Wind Turbulence ◽  
Proton Temperature ◽  
Wind Turbulence ◽  
First Time ◽  
Probe Mission

Abstract Based on the Parker Solar Probe mission, this paper presents the observations of two correlations in solar wind turbulence near the Sun for the first time, demonstrating the clear existence of the following two correlations. One is positive correlation between the proton temperature and turbulent magnetic energy density. The other is negative correlation between the spectral index and magnetic helicity. It is found that the former correlation has a maximum correlation coefficient (CC) at the wavenumber k ρ p ≃ 0.5 (ρ p being the proton thermal gyroradius), and the latter correlation has a maximum absolute value of CC at k ρ p ≃ 1.8. In addition, investigations based on 11 yr of Wind observations reveal that the dimensionless wavenumbers (k ρ p ) corresponding to the maximum (absolute) values of CC remain nearly the same for different data sets. These results tend to suggest that the two correlations enhanced near the proton gyroradius scale would be a common feature of solar wind turbulence.

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