Al-Swaidani A.M.,Arab International University
Archives of Civil Engineering | Year: 2017
The objective of the presented paper is to investigate the performance of concrete containing volcanic scoria as cement replacement after 7, 28, 90, and 180 days curing. Five performance indicators have been studied. Compressive strength, water permeability, porosity, chloride penetrability, and reinforcement corrosion resistance have all been evaluated. Concrete specimens were produced with replacement levels ranging from 10 to 35%. Test results revealed that curing time had a large influence on all the examined performance indicators of scoria-based concrete. Water permeability, porosity, and chloride penetrability of scoria-based concrete mixes were much lower than that of plain concrete. Concretes produced with scoria-based binders also decelerated rebar corrosion, particularly after longer curing times. Furthermore, an estimation equation has been developed by the authors to predict the studied performance indicators, focusing on the curing time and the replacement level of volcanic scoria. SEM/EDX analysis has been reported as well. © Polish Academy of Sciences 2017.
Al-Swaidani A.M.,Arab International University
Materiales de Construccion | Year: 2017
The objective of the study is to investigate strength and durability-related properties of volcanic scoria-based cements. Compressive and tensile strength development of mortars and concretes containing volcanic scoria with replacement levels ranging from 10 to 35% was investigated. Water permeability, chloride penetrability and porosity of concretes cured for 2, 7, 28, 90 and 180 days were also examined. Results revealed that volcanic scoria could be suitable for making blended cements. The strength of mortar/concrete containing volcanic scoria was lower than that of plain cement mortar/concrete at all ages. However, at 90 day curing, the strengths of volcanic scoria-based mortars/concretes were comparable to those of plain cement. In addition, water permeability, chloride penetrability and porosity of scoria-based concretes were much lower than those of plain concrete. Further, the results were statistically analysed and estimation equations have been developed to predict the studied properties. SEM/EDX analysis was employed, as well. © 2017 CSIC.
Shihabi K.,Arab International University
Jordan Journal of Civil Engineering | Year: 2017
The relationship between the design speed and the value of two-lane highway upgrade has a significant importance in determining whether this part of highway requires a climbing lane or not. Climbing lanes are added to ensure not reducing the safety on the highway, because the reduced speed of trucks on the upgrade results in obstructing the traffic behind them. Codes and references illustrated the cases when climbing lanes must be added in graphics, but these cases are limited by specific characteristics of trucks and specific design speeds. This leads to limitation of applicability of the graphics. In this research, general relationships that relate the value of upgrade to the design speed and to the predominant truck characteristics are concluded. These relationships are applicable for design speeds between 40 km/h and 130 km/h and for different truck characteristics. This makes them have a wider range of usage than the graphics included in the current codes and references. © 2017 JUST. All Rights Reserved.
Sayem El-Daher M.,Arab International University
Advances in Optical Technologies | Year: 2017
Thermal effects are the main obstacle to getting high power and good beam quality in diode end-pumped solid-state lasers. In this work, a theoretical investigation of thermal effects in single and dual end-pumped solid-state lasers is carried out using finite element analysis (FEA) for a selected number of widely used laser producing materials, namely, Nd:YAG, Yb:YAG, and Nd:KGW. Crystals with different dimensions are also investigated both in single and in dual end-pumped configuration. Finally, the effect of using composite crystals on thermal lensing is investigated. An experiment to measure the thermal focal length for two different crystals was carried out and a comparison with FEA computed focal length of the thermal lens is made. In all cases studied in this work, results show clear effects of thermal lensing with some differences depending on crystal type, pump power, and size. © 2017 Moustafa Sayem El-Daher.
Gansen P.,Otto Bock Kunststoff Holding GmbH |
Dittgen M.,Arab International University
Drug Development and Industrial Pharmacy | Year: 2012
The new technology to manufacture transdermal active patches without solvents or increased temperatures described here is based on polyol and isocyanate reacting to polyurethane (PU) in the presence of the drug. The technology was proven using testosterone (T) as the drug and N,N-Diethyl-m-toluamide (DEET) and Limonene (L) as enhancers for skin permeation. The experimental patches varied in drug content and enhancer concentration. The patches were evaluated regarding adhesion to stainless steel or leather, in vitro drug release and T permeation across human cadaver skin using Franz cell. Comparing the results with those of a parallel investigation of the commercial product, Testopatch®, adhesion to leather and in vitro drug release of the experimental patches were found to be higher. The steady-state flux (J SS) of T from the experimental patches was found lower than Testopatch®. The flux of the experimental patch P3, which had the highest concentration of DEET and a low concentration of L was comparable to J SS of the commercial product, Testopatch®. © 2012 Informa Healthcare USA, Inc.
Baqar M.,Case Western Reserve University |
Baqar M.,Arab International University |
Agag T.,Case Western Reserve University |
Ishida H.,Case Western Reserve University |
Qutubuddin S.,Case Western Reserve University
Polymer | Year: 2011
Historically, applications for traditional phenolic resin/polyurethane materials are limited due to the inherently weak thermal stability of urethane-phenolic linkage and slow reaction rate. A novel concept has been developed to produce phenolic resin/polyurethane copolymers via benzoxazine chemistry. Through one-pot synthesis, a series of linear poly(benzoxazine-co- urethane) materials has been synthesized via the reaction of a newly developed dimethylol functional benzoxazine monomer with 4,4′-methylene diphenyl diisocyanate and poly(1,4-butyleneadipate). The structure of the copolymers has been characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR). The copolymers in the film forms have been further thermally treated for crosslinking to produce crosslinked poly(benzoxazine-co-urethane) via the ring opening polymerization of cyclic benzoxazine moieties in the main-chain. The tensile properties of the films have been studied and compared with those of traditional high performance materials. The thermal properties of the crosslinked copolymers have also been studied by dynamic mechanical analysis, and thermogravimetric analysis (TGA). © 2010 Elsevier Ltd. All rights reserved.
Ali B.,Arab International University |
Sadek M.,Lille University of Science and Technology
Arabian Journal of Geosciences | Year: 2013
The use of rubber pavement technology, also known as ecological pavement, offers a solution to a problem of worldwide dimensions. The rubber-modified asphalt becomes an excellent alternative compared to conventional asphalt. A series of laboratory tests was conducted to evaluate the effect of tire rubber addition on the performance of asphalt and asphalt concrete produced in Syria. The paper is composed of three parts: the first part includes a literature review on asphalt aging and the use of modified rubber asphalt in pavement road applications. The second part emphasizes rheological properties of two types of Syrian asphalt hard and soft and analyzes the influence of short-term aging on each type of asphalt. The last part presents a comparison of properties obtained for both cases of nonmodified asphalt and crumb rubber-modified asphalt that have been subjected to short-term aging. Results show an improvement of the resistance to short-term aging for the crumb rubber-modified asphalt. It also demonstrates that adding tire rubber to asphalt improves the performance of asphalt concrete by increasing its stability and reducing permanent deformations. © 2011 Saudi Society for Geosciences.
Al-Swaidani A.M.,Arab International University
CONCREEP 2015: Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures - Proceedings of the 10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures | Year: 2015
Use of blended cements is growing rapidly in the construction industry due to economical, ecological and technical benefits. Syria is relatively rich in volcanic scoria. In the study, three types of cement were prepared; one plain Portland cement CEM I (control) and two blended cements: CEM II/A-P and CEM II/B-P (EN 197-1), each of them with three replacement levels of scoria: (10%, 15%, 20%) and (25%, 30%, 35%), respectively. Evaluation of sulfate resistance of mortars containing scoria-based cements was performed in accordance with ASTM C1012. Length measurements were performed up to 52 weeks after immersing the specimens into 5% Na2SO4 solution. Drying shrinkage has been evaluated using mortar bar method in accordance with ASTM C596. Lengths of mortar bars subjected to drying shrinkage were measured periodically up to 360 days. SRPC cement was employed for comparison in both tests. Test results revealed that the increase of scoria significantly improves the sulfate resistance of mortars. The expansion of scoria-based mortar bars decreased with the increase of scoria replacement level. Further, according to the expansion test results, CEM II/B-P can be used instead of SRPC in sulfate-bearing environments. The results of drying shrinkage showed that the CEM II/B-P-based mortar bars exhibited greater contraction when compared to the control mortar, especially at early ages. However, the long-term drying shrinkage of mortars was not influenced much by the addition of volcanic scoria. © ASCE.
Mahmoud A.B.,Arab International University
Business: Theory and Practice | Year: 2013
The goal of this research is to determine the dimensions of beliefs about internet advertising affecting Syrian consumers' attitudes and behaviors towards internet advertising. The results indicate that Attitudes are influenced positively by information, and entertainment; and negatively by irritation and values' corruption. Irritation positively influences consumers' behaviors of leaving websites showing the ads. Entertainment positively influences consumers' behaviors of clicking on internet ads for further information concerning advertised products. Attitude is found to fully mediate the relationships between beliefs of information, irritation, and values' corruption and the behaviors clicking on internet ads, and partially mediate the relationship between entertainment and the behaviors of clicking on internet ads. Attitudes fully mediate the relationships between beliefs of information, entertainment, and values' corruption and the behaviors of leaving websites showing the ads, and partially mediate the relationship between irritation and the behaviors of leaving websites showing the ads. This research comes to be one of the first studies to investigate Syrian consumers' beliefs about, attitudes, and behavioral responses towards internet advertising. As well as, this study provides evidence of the direct relationship between some of the beliefs about internet advertising (i.e. entertainment and irritation) and the behavioral responses towards it. © 2013 Vilnius Gediminas Technical University (VGTU) Press Technika.
Shammaa Y.,Arab International University |
Zhu D.Z.,University of Alberta
Journal of Hydraulic Engineering | Year: 2010
An experimental study was conducted to investigate the use of a temperature-control curtain in selective withdrawal from a two-layer stratified reservoir. This study focused on the case where cool water at a depth was forced to flow under the curtain. The evolution of the mean flow, the withdrawal water quality, and the mean velocity field were studied using particle image velocimetry and laser-induced fluorescence. Practical relationships were developed for predicting the withdrawal water quality and the interface height as a function of time. The structures of the flow field in both the upper and lower layers are discussed in detail. The flow in the lower layer was dominated by the recirculation eddy induced by the jet flow under the curtain and a relation between the eddy length and the interface height was obtained. Close to the intake, within about 3d (where d=intake diameter), the velocity field can be well described by the potential flow theory. Beyond 3d, however, the flow field considerably deviated from the potential flow theory due to the jet expansion and stratification. A general discussion of the results and engineering applications are also provided. © 2010 ASCE.