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Your search keyword '"Rouhollahi, R."' showing total 9 results
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9 results on '"Rouhollahi, R."'

4. Source Process and Slip Model of 2005 Dahuiyeh-Zarand Earthquake (Iran) Using Inversion of Near-Field Strong Motion Data

Author

Rouhollahi, R., Ghayamghamian, M. R., Yamini Fard, F., Suhadolc, Peter, Tatar, M., Rouhollahi, R., Ghayamghamian, M. R., Yamini Fard, F., Suhadolc, Peter, and Tatar, M.

Subjects
Earthquake dynamics, Earthquake source observation, Earthquake source observations, Site effects, Earthquake dynamic, Earthquake ground motions, Earthquake ground motion
Abstract

On 2005 February 22, the Dahuiyeh-Zarand earthquake, Mw 6.5, struck one of the most seismically active regions in south-central Iran, east of Zarand City in Kerman province,causing more than 500 fatalities. The causative fault of the 2005 Dahuiyeh-Zarand earthquake, a reverse fault, striking nearly EW and dipping to the north, was located within a mountainous region and therefore more difficult to identify compared to the range-bounded faults. Its identification, after the 2005 event, is very important for both the estimation of seismic hazard as well as for the damage and fatality functions. We have inverted six three-component nearfield strong motion waveforms to obtain the complete earthquake rupture history and slip distribution. Accelerograms are bandpass filtered with 0.2–1.0 Hz, and a length of 15–17 s of the waveforms is inverted. The lack of absolute timing has been successfully overcome by estimating, from the velocity model of the region, the propagation of P and S waves from the epicentre to the stations. The final fault slip model and the estimated source parameters are able to explain the observed waveforms. The rupture is found to be bilateral with a maximum slip of 2.4 m concentrated on two asperities in the west and east sides of the nucleation point at depths of 6–12 km. The western asperity is located to the east of Zarand City and beneath the Dahuiyeh village, which might explain why the Dahuiyeh village was totally destroyed by this earthquake.

Published
2012

7. Application of Electric Field to Developing Falling Films using Wire-Plate Electrode Configuration- An Experimental Study.

Author

Rouhollahi, R., Islami, S. Baheri, Gharraei, R., and Nobari, M. R. Heirani

Subjects
ELECTROHYDRODYNAMICS, ELECTRIC fields, REYNOLDS number
Abstract

Experimental investigation of Electrohydrodynamic developing falling film flow of transformer oil has been conducted within an inclined rectangular channel and hydrodynamic characteristics of the flow have been revealed. The electric field has been generated by five overhead thin wire electrodes connected to the positive high DC voltage on the air and the grounded plate electrodes which are placed upon the floor of the channel. It is the first time that the wavy behavior on a liquid falling film's interface has been created by this electrode configuration. A non-intrusive method has been used to measure the local flow structure by a high-speed camera, then statistical characteristics of the wavy falling film have been computed by image processing of the captured video frames. By applying 13-16 kV to the wire electrodes, the influence of EHD force on the wavy behavior of falling film has been conducted for Reynolds number 10-120 in the laminar-wavy regime at three different inclination angles 15°, 30° and 45°. The vertical distance of the high-voltage wire electrodes to ground electrodes has been set to 14 mm. The liquid velocity, film thickness, and wave frequency have been measured for non-electrified and electrified falling film, and their results have been evaluated with other experimental studies and an acceptable agreement has been obtained. The results indicate that the proposed HV wire-grounded plate electrode configuration in this study does not disturb the original structure of the falling film and by intensifying the wavy behavior of laminar falling film can either suppress or enhance heat/mass transfer rate. The effects of the applied voltage on the frequency, velocity and film thickness of the falling liquid film have been also discussed in detail. [ABSTRACT FROM AUTHOR]

Published
2018
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9. The effect of trace-anomaly on ω=−1 crossing in f(R,T) gravity

Author

Banijamali, A., Fazlpour, B., Rouhollahi, R., and Gholamzadeh, M.

Abstract

We study the phantom-divide line crossing in f(R,T) gravity theories, where the gravitational Lagrangian is described by an arbitrary function of the Ricci scalar Rand of the trace of the energy-momentum tensor T. Although crossing of ω=−1 does not occur at classical level, quantum contributions induce such a crossing for particular classes of f(R,T) models obtained by explicitly specifying the functional form of f. The quantum effects are considered via the account of trace (conformal) anomaly. Our results coincide with the results obtained for well-known modified theories of gravity such as f(R) and f(G) models.

Published
2016
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