Publications

Export 4918 results:
Sort by: Author [ Title  (Desc)] Type Year
A B C [D] E F G H I J K L M N O P Q R S T U V W X Y Z   [Show ALL]
D
Sakr, A. H., "Dynamics of Heaving Buoy Wave Energy Converters with a Stiffness Reactive Controller", Energies, vol. 14, no. 1, 2021. AbstractWebsite

Heaving buoy wave energy converters (WEC) are floating oscillators, commonly modeled as single-degree-of-freedom vibrating systems. As the wave frequencies change according to the sea state, these devices must be controlled to maximize energy absorption. A new short-term reactive loading control technique is proposed that maximizes power absorption. The control is realized through tuning the effective stiffness of the vibrating system; thus, adjusting its natural frequency to meet the incident waves energy frequency achieving near-to-resonance operation and maximum power absorption. This stiffness is adjusted using an external stiffness, whose value is varied by a continuously variable transmission (CVT) mechanism connected to the buoy. The system equations were derived then solved analytically to calculate the controller bandwidth. Experiments demonstrated promising results for near-resonance tuning at different input frequencies. Results show that an optimized damping value exists at which power absorption can be significantly increased. The WEC equipped with the proposed reactive controller can provide faster tuning actions than long-term techniques. It also works on longer time intervals than phase-control methods; hence, reducing the continuous demands from the PTO system.

Sakr, A. H., S. M. Metwalli, and Y. H. Anis, "Dynamics of Heaving Buoy Wave Energy Converters with a Stiffness Reactive Controller", Energies, vol. 14, no. 1, 2020. AbstractWebsite

Heaving buoy wave energy converters (WEC) are floating oscillators, commonly modeled as single-degree-of-freedom vibrating systems. As the wave frequencies change according to the sea state, these devices must be controlled to maximize energy absorption. A new short-term reactive loading control technique is proposed that maximizes power absorption. The control is realized through tuning the effective stiffness of the vibrating system; thus, adjusting its natural frequency to meet the incident waves energy frequency achieving near-to-resonance operation and maximum power absorption. This stiffness is adjusted using an external stiffness, whose value is varied by a continuously variable transmission (CVT) mechanism connected to the buoy. The system equations were derived then solved analytically to calculate the controller bandwidth. Experiments demonstrated promising results for near-resonance tuning at different input frequencies. Results show that an optimized damping value exists at which power absorption can be significantly increased. The WEC equipped with the proposed reactive controller can provide faster tuning actions than long-term techniques. It also works on longer time intervals than phase-control methods; hence, reducing the continuous demands from the PTO system.

Sakr, A. H., S. M. Metwalli, and Y. H. Anis, "Dynamics of Heaving Buoy Wave Energy Converters with a Stiffness Reactive Controller", Energies, vol. 14, no. 1: Multidisciplinary Digital Publishing Institute, pp. 44, 2021. Abstract
n/a
Abdelnaby, E. A., and A. A. M. El-Maaty, "Dynamics of Follicular Blood Flow, Antrum Growth, and A n g i o ge n i c M e d i a to r s i n M a re s Fro m D e v i a t i o n t o O v u l a t i o n", Journal of Equine Veterinary Science, vol. 55, pp. 51-59, 2017.
Selwaness, I., and C. Krafft, "The Dynamics of Family Formation and Women’s Work: What Facilitates and Hinders Female Employment in the Middle East and North Africa?", Economic Research Forum Working Paper Series No. 1192. Cairo, Egypt, 2018. Abstract

This paper investigates the dynamic relationship between family formation and women’s employment, a previously unexplored aspect of female labor force participation in MENA region. The paper studies Egypt, Jordan and Tunisia, leveraging unique retrospective data on work, marriage, child bearing and child rearing. The time variation allows us to estimate discrete hazard models for the duration of different labor statuses. This paper examines three sets of outcomes:(1) duration in employment,(2) duration in non-employment, and (3) duration in different labor market states and specific types of work. Findings show that anticipating marriage and childbearing are strongly associated with women’s employment outcomes. Non-employment is an absorbing state, particularly after marriage.

Selwaness, I., and C. Krafft, "The dynamics of family formation and women’s work: what facilitates and hinders female employment in the Middle East and North Africa?", Population Research and Policy Review: Springer, pp. 1-55, 2020. Abstract
n/a
Zafar, A., M. Raheel, M. Q. Zafar, K. S. Nisar, M. S. Osman, R. N. Mohamed, and A. Elfasakhany, "Dynamics of Different Nonlinearities to the Perturbed Nonlinear Schrödinger Equation via Solitary Wave Solutions with Numerical Simulation", fractal and fractional, vol. 5, pp. 213, 2021.
Ramadan, N., and J. Child, "The Dynamics of Cross Border Inter-Unit Learning and Knowledge Transfer.", West Midlands Doctoral Colloquium, Birmingham, UK, 2010.
Eid, A., "Dynamics of charged shell with a cosmological constant", New Astronomy, vol. 44, pp. 17 - 20, 2016. AbstractWebsite

Abstract Using the Darmois–Israel formalism technique, charged thin shell in the presence of a cosmological constant is constructed. An equation governing the behavior of the radial pressure across the junction surface is deduced. The cosmological constant term and the charge term slows down the collapse of matter. The spherical N-shell model with an appropriate initial condition imitates quite well the \{FRW\} universe with Λ ≠ 0.

, "Dynamics of charged shell with a cosmological constant", New Astronomy, vol. 44, pp. 17 - 20, 2016. AbstractWebsite

Abstract Using the Darmois–Israel formalism technique, charged thin shell in the presence of a cosmological constant is constructed. An equation governing the behavior of the radial pressure across the junction surface is deduced. The cosmological constant term and the charge term slows down the collapse of matter. The spherical N-shell model with an appropriate initial condition imitates quite well the \{FRW\} universe with Λ ≠ 0.

Eid, A., "Dynamics of charged shell with a cosmological constant", New Astronomy, vol. 44, pp. 17 - 20, 2016. Website
Soliman, W., T. Nakano, N. Takada, and K. Sasaki, "Dynamics of cavitation bubbles induced by laser ablation in pressurized water: comparison between experiment and theory", Extended abstract in the 55th Spring Meeting, 2008; The Jpn. Soc. Appl. Phys., Funabashi, Chiba, Japan, Japan, 2008.
Nakano, T., W. Soliman, N. Takada, and K. Sasaki, "Dynamics of cavitation bubble induced by laser ablation in water", abstract in 6th Int. Conf. on photo-excited processes and Application, Sapporo, Hokkaido, 9-12 September, Japan, 2008.
Rahoma, W. A., and A. F. A. El-Salam, "Dynamics of an infinitesimal body with a decreasing mass in the restricted three body problem apart from the equilibrium points", Elixir Appl. Math., vol. 76, pp. 28268-28274, 2014.
Rahoma, W. A., and A. F. A. El-Salam, "Dynamics of an infinitesimal body with a decreasing mass in the restricted three body problem apart from the equilibrium points", Elixir Appl. Math., vol. 76, pp. 28268-28274, 2014.
Rahmonov, I. R., Y. M. Shukrinov, and R. Dawood, "Dynamics of a SQUID with topologically nontrivial barriers.", JETP Letters , vol. 103, issue 6, pp. 395-398, 2016.
Hassaan, G. A., "Dynamics of a nonlinear automatic door closing torsional mechanism", International Journal of Innovation and Applied Studies, vol. 8, issue 4, pp. 1669-1678, 2014. doorclosingmechanism.pdf
Hassaan, G. A., "Dynamics of a cannon barrel-recoil mechanism with nonlinear hydraulic damper", International Journal Scientific & Engineering Technology, vol. 1, issue 5, pp. 82-91, 2014. barrel_recoildyn_hyddamper.pdf
Hassaan, G. A., "Dynamics of a cannon barrel-recoil mechanism with nonlinear air springs", International Journal of Innovation & Applied Studies, vol. 9, issue 2, pp. 511-522, 2014. ijias_cannon_airsprings.pdf
Attia, S., S. Shabka, Z. Shafik, and A. Ibrahim, Dynamics and Resilience of Informal Areas, , Germany, Springer, 2016.
Attia, S., S. Shabka, Z. Shafik, and A. Ibrahim, Dynamics and Resilience of Informal Areas, , 2016. Abstract
n/a
Hegazy, O., Kabiel, H. F., A. A. Alatar, and J. Lovett-Doust, "Dynamics and persistence of Anastatica hierochuntica populations under simulated rainfall treatments. ", Polish Journal of Ecology, vol. 61, pp. 493-504, 2013.
Tourism