Papers by Hadi Al-Qahtani
Canadian Journal of Physics, 2011
ABSTRACT
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Optics and Laser Technology, 2009
Laser evaporative heating of the solid surface is considered and the effect of temporal variation... more Laser evaporative heating of the solid surface is considered and the effect of temporal variation of laser pulse shape on temperature rise is examined. In the analysis, time exponentially varying and step input pulses are employed and closed-form solutions for temperature rise are presented. Comparison of temporal variation of surface temperature is carried out for various laser pulse parameters of exponential and step input pulses. The pulse energies are kept the same for all pulses used in the comparison. It is found that temperature distributions corresponding to pulses used in the simulations are different and temperature decay in cooling cycle (after ending of the laser pulse) is clearly evident for step input pulses; however, this is not clearly identified for exponential pulses.
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Journal of Urology, 2009
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Head and Neck-journal for The Sciences and Specialties of The Head and Neck, 2009
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Physica B-condensed Matter, 2010
The analytical solution for the temperature and stress fields in a solid subjected to a step inpu... more The analytical solution for the temperature and stress fields in a solid subjected to a step input pulse heating is presented. The closed form solutions of Cattaneo and thermal stress equations are obtained using the Laplace transformation technique. The predictions obtained from the closed form solutions are presented in nondimensional form. It is found that temperature rise is rapid in the early heating period and as the time progresses, temperature rise becomes gradual. The stress generated in the heating cycle is tensile while it becomes compressive in the cooling cycle.
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Studies in Surface Science and Catalysis, 1996
The production of synthesis gas (CO, H2) from methane by partial oxidation is investigated over c... more The production of synthesis gas (CO, H2) from methane by partial oxidation is investigated over commercial steam reforming catalyst at several flow rates, temperatures, and at different methane/oxygen ratios (R). Optimum synthesis gas selectivity and yield achieved are 70% and 60%, respectively at methane/oxygen ratio close to 2 and at flow rates of 500 cm3/min. An initial temperature (665°C) is necessary to initiate the reaction and then the reaction is stabilized at 883°C. The effect of methane/oxygen ratios and residence time are effective in determining the synthesis gas selectivity and yield.
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Optical Engineering, 2004
Characteristics of GaAs/AlGaAs vertical-cavity surface-emitting lasers irradiated with gamma rays... more Characteristics of GaAs/AlGaAs vertical-cavity surface-emitting lasers irradiated with gamma rays. [Optical Engineering 43, 2184 (2004)]. Abdullah S. Aldwayyan, Hadi R. Al-Qahtani, Mohammed Alsalhi, M. Yasin Akhtar Raja. Abstract. ...
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Canadian Journal of Physics, 2011
ABSTRACT
Bookmarks Related papers MentionsView impact
Optics and Laser Technology, 2009
Laser evaporative heating of the solid surface is considered and the effect of temporal variation... more Laser evaporative heating of the solid surface is considered and the effect of temporal variation of laser pulse shape on temperature rise is examined. In the analysis, time exponentially varying and step input pulses are employed and closed-form solutions for temperature rise are presented. Comparison of temporal variation of surface temperature is carried out for various laser pulse parameters of exponential and step input pulses. The pulse energies are kept the same for all pulses used in the comparison. It is found that temperature distributions corresponding to pulses used in the simulations are different and temperature decay in cooling cycle (after ending of the laser pulse) is clearly evident for step input pulses; however, this is not clearly identified for exponential pulses.
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Journal of Urology, 2009
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Head and Neck-journal for The Sciences and Specialties of The Head and Neck, 2009
Bookmarks Related papers MentionsView impact
Physica B-condensed Matter, 2010
The analytical solution for the temperature and stress fields in a solid subjected to a step inpu... more The analytical solution for the temperature and stress fields in a solid subjected to a step input pulse heating is presented. The closed form solutions of Cattaneo and thermal stress equations are obtained using the Laplace transformation technique. The predictions obtained from the closed form solutions are presented in nondimensional form. It is found that temperature rise is rapid in the early heating period and as the time progresses, temperature rise becomes gradual. The stress generated in the heating cycle is tensile while it becomes compressive in the cooling cycle.
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Studies in Surface Science and Catalysis, 1996
The production of synthesis gas (CO, H2) from methane by partial oxidation is investigated over c... more The production of synthesis gas (CO, H2) from methane by partial oxidation is investigated over commercial steam reforming catalyst at several flow rates, temperatures, and at different methane/oxygen ratios (R). Optimum synthesis gas selectivity and yield achieved are 70% and 60%, respectively at methane/oxygen ratio close to 2 and at flow rates of 500 cm3/min. An initial temperature (665°C) is necessary to initiate the reaction and then the reaction is stabilized at 883°C. The effect of methane/oxygen ratios and residence time are effective in determining the synthesis gas selectivity and yield.
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Optical Engineering, 2004
Characteristics of GaAs/AlGaAs vertical-cavity surface-emitting lasers irradiated with gamma rays... more Characteristics of GaAs/AlGaAs vertical-cavity surface-emitting lasers irradiated with gamma rays. [Optical Engineering 43, 2184 (2004)]. Abdullah S. Aldwayyan, Hadi R. Al-Qahtani, Mohammed Alsalhi, M. Yasin Akhtar Raja. Abstract. ...
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Papers by Hadi Al-Qahtani