O'Connor A.J.,Trinity College Dublin |
Kenshel O.,University of Tripoli
Journal of Bridge Engineering | Year: 2013
This paper provides experimentally determined estimates of the scale of fluctuation of the principal variables employed in modeling chloride-induced corrosion for reinforced concrete; i.e., the surface chloride content (Cs) and apparent diffusion coefficient (Dapp). The estimation of the scale of fluctuation, θ, is based on the analysis of experimental data recorded on a bridge in South East Ireland prior to its extensive rehabilitation in 2007. In determining the scale of fluctuation the paper considers two commonly used methods; i.e., the maximum likelihood method and the autocorrelation curve-fitting method. The reliability of both methods is discussed. Introduction of the kriging statistical interpolation method is demonstrated to improve the reliability of the estimates of the scale of fluctuation. The results obtained from the analysis are compared with values in the literature proffered by other researchers. © 2013 American Society of Civil Engineers.
Eajal A.A.,University of Tripoli |
El-Hawary M.E.,Dalhousie University
IEEE Transactions on Power Delivery | Year: 2010
Shunt capacitors installation in distribution systems requires optimal placement and sizing. More harmonics are being injected into distribution systems. Adding shunt capacitors may lead to high distortion levels. The capacitor placement and sizing problem is a nonlinear integer optimization problem, with locations and ratings of shunt capacitors being discrete values. The goal is to minimize the overall cost of the total real power loss and that of shunt capacitors while satisfying operating and power quality constraints. This paper proposes to solve the problem using particle swarm optimization (PSO). A discrete version of PSO is combined with a radial distribution power flow algorithm (RDPF) to form a hybrid PSO algorithm (HPSO). The former is employed as a global optimizer to find the global optimal solution, while the latter is used to calculate the objective function and to verify bus voltage limits. To include the presence of harmonics, the developed HPSO was integrated with a harmonic power flow algorithm (HPF). The proposed (HPSO-HPF)-based approach is tested on an IEEE 13-bus radial distribution system (13-Bus-RDS). The findings clearly demonstrate the necessity of including harmonics in optimal capacitor placement and sizing to avoid any possible problems associated with harmonics. © 2010 IEEE.
Nasrallah N.F.,University of Tripoli
Physical Review C - Nuclear Physics | Year: 2013
QCD sum rules using polynomial kernels are used to evaluate the strong part of the proton-neutron mass difference δMnp in a model independent fashion. The result for the mass difference turns out to depend sensitively on the value of the four-quark condensate (q̄q) 2 and reproduces the experimental value of δMnp for (q̄q)2 q̄q2. © 2013 American Physical Society.
Taher Y.A.,University of Tripoli
Libyan Journal of Medicine | Year: 2012
Background: Mentha piperita L. (Labiatae) is an herbaceous plant, used in folk medicine for the treatment of several medical disorders. Methods and Results: In the present study, the aqueous extract of Mentha piperita leaf, at the i.p doses 200 and 400 mg/kg, showed significant analgesic effects against both acetic acid-induced writhing and hot plateinduced thermal stimulation in mice, with protection values of 51.79% and 20.21% respectively. On the contrary, the Mentha piperita leaf aqueous extract did not exhibit anti-inflammatory activity against carrageenan induced paw oedema. Conclusion: These findings indicate that Mentha piperita has a potential analgesic effect that may possibly have mediated centrally and peripherally, as well as providing a pharmacological evidence for its traditional use as a pain reliever. © 2012 Yousef A. Taher.
Agina A.M.,University of Tripoli
Computers in Human Behavior | Year: 2012
The present study sought to examine the effect of nonhuman's external regulation on children's self-regulation to regulate their own process of learning and to what extent did children succeed in terms of application when they talk and think while act alone with nonhuman's external regulator. The Aginian's methodology (Agina, Kommers, & Steehouder, 2011a, 2011b, 2011c, 2011d, 2011e) that used an isolated, computer-based learning system and acts as a standalone learning environment with special set of tasks was used by hundred healthy preschool children. The results showed that young children were able to regulate their own process of learning and engage with their full free-will without the need of their real teacher's regulation. The conclusion provided evidence that the verbalization of thinking aloud should occur spontaneously by nature, the nonhuman's external regulation has a positive effect on young children's development when they act with their full free-will, and has a positive effect on their behavior either. © 2012 Elsevier Ltd. All rights reserved.