Hariri Canadian University

Canadian, Lebanon

Hariri Canadian University

Canadian, Lebanon
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Tarnini M.Y.,Hariri Canadian University
EPEC 2010 - IEEE Electrical Power and Energy Conference: "Sustainable Energy for an Intelligent Grid" | Year: 2010

Power harmonic is the important factors affect the safety of transmitting and transforming power. This paper presents a news simplified series single-phase active power filter based on controlling harmonic levels in residential and commercial areas. We developed it in order to define new control schemes characterized by simple control algorithms, reduced number of current transducers, and a less price controller. It is able to install easily in any non-linear device. The proposed filter can improve especially for the harmonic defects arising from small non-linear loads like as computers, faxes, photocopier machines, printers...etc. The amplitude and the shape of the fundamental current are controlled through the microcontroller (PIC16f788). The harmonic rate of the distortion after filtering is lower than 5%, which is less than the maximum accepted value by the international recommendations standards. ©2010 IEEE.


Taha M.,Hariri Canadian University
Proceedings of the 2011 14th European Conference on Power Electronics and Applications, EPE 2011 | Year: 2011

There is a general move in the aerospace industry to increase the amount of electrically powered equipments on future aircraft. This trend is referred to as the "More Electric Aircraft". It assumes using electrical energy instead of hydraulic, pneumatic and mechanical means to power virtually all aircraft subsystem including flight control actuation, environmental control system and utility function. The concept offers advantages of reduced overall aircraft weight, reduced need for ground support equipment and maintenance and increased reliability [1, 2]. Many aircraft power systems are now operating with a variable frequency over a typical range of 360 Hz to 800 Hz. Distribution voltages for an aircraft system can be classified as: Nominal 14, 28 and 42 V dc. Nominal 115/200 V rms and 230/400 V rms ac, both one phase and three phase, over variable frequency range. This paper presents simulation results for a buck 3 phase converter at variable input frequency, which provide a 42 DC power supply for aircraft system. The design of this system poses significant challenges due to the supply frequency variation and requires many features such as: 1. The supply current to the converter must have a low harmonic content to minimize its impact on the aircraft variable frequency electrical system. 2. A high input power factor must be achieved to minimize reactive power requirements. 3. Power density must be maximized for minimum size and weight. © 2011 EPE Association - European Power Electr.


Khodr M.,Hariri Canadian University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

Temperature dependence is a key parameter in designing quantum well lasers. In this work, we calculated the effects of temperature on the energy levels and emitted wavelength for PbSe/PbSrSe Single Quantum Well Laser at four different temperatures: 77K, 150K, 200K, 250K, and 300K. This material system is currently being used in Tunable Laser Spectroscopy which plays a key role in detecting biomarker molecules in exhaled breath at wavelengths in the infrared region. We determined the system design parameters to obtain the desired emitted wavelengths associated with certain disease biomarkers as a function of temperature. Our calculated emitted wave lengths are in excellent agreement with experimental data assuming parabolic and nonparabolic energy band structures. Moreover, we calculated the effects of temperature on the confinement factor, gain and current density. The modal gain versus current density curved showed that the nominal current density and the saturation level increases with temperature similar to other material systems. © 2012 SPIE.


Khodr M.,Hariri Canadian University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

In order for laser oscillation to occur, the modal gain at the lasing photon energy must equal the total losses. In this work, we analyze and calculate the total losses due to the free carrier absorption, optical waveguide scattering and the laser cavity end losses for PbSe/Pb 0.934Sr 0.066 Se quantum well laser structures. The small confinement factor value causes the free carrier absorption loss to be negligible. The calculated scattering loss values showed a decreasing order for the MQW, MMQW and SCH-SQW structures, for a surface roughness amplitude of 10nm. Increasing the surface roughness amplitude increases these scattering losses even further. However, the calculated cavity loss calculations showed that its values are in an increasing order for the MQW (or MMQW) and SCH-SQW structures. These cavity losses are lowest for uncoated cavity ends. Coating these ends with a quarter wavelength BaF2 layer increases the total cavity loss. In addition, coating the cavity ends with alternating quarter wavelength layers of BaF 2 and CaF 2 also results in an increase in the cavity loss. The increase in cavity loss due to coating is caused by the decrease in the mirrors' reflectivity values. These results show that coating with fluoride layers can best be utilized in applications where high transitivity values are needed. © 2010 SPIE.


Al-Aawar N.,Hariri Canadian University | Hijazi T.M.,Hariri Canadian University | Arkadan A.A.,Hariri Canadian University | Arkadan A.A.,Marquette University
IEEE Transactions on Magnetics | Year: 2011

This work investigates the feasibility of utilizing an electromagnetic-team fuzzy logic (EM-TFL) robust identifier for use with the particle swarm optimization technique to increase the efficiency and fuel economy of a hybrid electric vehicle (HEV) powertrain system in series configuration. This optimization necessitates the characterization of the key electromechanical components of the hybrid electric powertrain system which includes a PM generator and an electric motor drive system. The basic objective of improving the fuel economy while maintaining the performance of the vehicle is met through the implementation of a particle swarm optimization algorithm. © 2011 IEEE.


Khodr M.,Hariri Canadian University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Threshold current is a key parameter in the design and proper operation of quantum well lasers. In this publication, threshold current analysis and calculations are done on four PbSe/Pb0.934Sr0.066Se quantum well laser structures: SQW, SCH-SQW, MQW, and MMQW. The current work is a continuation to previous publications where energy levels, modal gain, optical confinement, and total losses were published for these four structures assuming the energy bands are nonparabolic. The threshold current as a function of total losses, cavity length, and cavity end mirror reflectivity was obtained for these structures. It is shown that the threshold current decreases with a decrease in the cavity length and then increases at a critical cavity length. The effects of non-parabolicity on the threshold current values are more obvious for short cavities and decreases with an increase in cavity. Whether the SQW or the MQW is the better structure depends on the loss level. At low loss, the SQW laser is always better because of its lower current density where only one QW has to be inverted. At high loss, the MQW is always better because the phenomena of gain saturation can be avoided by increasing the number of QW's although the injected current to achieve this maximum gain also increases. Owing to this gain saturation effect, there exists an optimum number of QW's for minimizing the threshold current for a given total loss. At this typical value, the effects of non-parabolicity on the threshold current values can be neglected without loss of accuracy. However, there is a 20% shift in the output lasing energy that cannot be neglected. © 2011 SPIE.


Kasti N.A.,Hariri Canadian University
Advanced Materials Research | Year: 2012

When using structural mechanics to study the deformation of carbon nanotubes (CNTs), one has to pick the structural mechanics properties that are equivalent to the molecular mechanics properties. In a previous publication [1], we have determined the relation between the bending stiffness EI/a used in structural mechanics and the bond bending stiffness C used in molecular mechanics for zigzag carbon nanotubes under simple tension. This paper extends the concept and determines the corresponding relation for simple torsion. We show that the relation obtained is different than that of simple tension; in simple torsion, EI/a is load and chirality dependent. However, for the particular case of a graphene sheet, simple tension and torsion lead to the same value of EI/a, namely C/2. We also include the structural mechanics deformation of the tube that accounts for axial, bending and torsional structural stiffnesses. Unlike simple tension, the deformation in the case of simple torsion has the axial stiffness coupled to the bending and torsional stiffnesses. © (2012) Trans Tech Publications.


Ghanem H.,Hariri Canadian University | Zollinger D.,Texas A&M University | Lytton R.,Texas A&M University | Ghanem N.,University of Balamand
Construction and Building Materials | Year: 2012

Alkali-silica reaction (ASR) is a major durability problem in concrete leading to premature deterioration of different types of concrete structures. Current laboratory tests are largely simulative in nature and yield mainly empirical results, and users state that there is little relationship between the test, the results and actual field performance. A different approach is necessary. This paper is part of a broader research study to assist owners, engineers, and contractors to identify and quantify the potential for concrete pavement deterioration, as a result of ASR. To achieve this objective, a comprehensive study on concrete and mortar mixtures using different types of aggregates of different reactivity was conducted to formulate a reliable and timely testing protocol. A kinetic model was proposed to predict ASR characteristics which were calculated using the system identification method. From test results, it was determined that the proposed testing approach provides direct accountability for various factors affecting ASR, such as aggregate reactivity, calcium concentration, presence of fly ash, and solution alkalinity. Chemistry of the alkali solution validates the laboratory research findings. © 2012 Elsevier Ltd. All rights reserved.


Ghanem H.,Hariri Canadian University | Zollinger D.,Texas A&M University | Lytton R.,Texas A&M University
Construction and Building Materials | Year: 2010

Alkali-silica reaction has become in concrete structures a growing and annoying problem for engineers, contractors and government agencies. Laboratory standards tests like ASTM C 1260 and ASTM C 1293 are available and are currently used by researchers and agencies. However, those tests have limitations and drawbacks. Those short comings warrant a completely different approach to ASR testing. Hence, a detailed study was conducted to develop a reliable aggregate test protocol that will assist the engineers, contractors and owners to identify and measure the potential for concrete pavement degradation because of ASR. Results indicate that the activation energy concept of ASR can be seen as a useful parameter and has the potential of playing the role of a screening parameter for rocks with different reactivity. Statistical analysis conducted shows that the test protocol is highly repeatable and reliable. © 2009 Elsevier Ltd. All rights reserved.


Ghanem H.,Hariri Canadian University | Zollinger D.,Texas A&M University | Lytton R.,Texas A&M University
Journal of Materials in Civil Engineering | Year: 2010

Although concrete is widely considered a very durable material, if conditions are such, it can be vulnerable to deterioration and early distress development. Alkali-silica reaction (ASR) is a major durability problem in concrete structures. The product of this reaction is a gel that is hygroscopic in nature. When the gel absorbs moisture, it swells leading to tensile stresses in concrete. When those stresses coming from the gel swelling exceed the tensile strength of concrete, cracks occur. This paper is part of a broader research study to assist engineers to effectively mitigate ASR in concrete, leading to an increase in the life span of concrete structures. To achieve this objective, a comprehensive study on different types of aggregates of different reactivity was conducted to formulate a robust approach that takes into account the factors affecting ASR, such as temperature, moisture, calcium concentration, and alkalinity. A kinetic model was proposed to determine aggregate ASR characteristics which were calculated using the system identification method. Analysis of the results validates that ASR is a thermally activated process and, therefore, the reactivity of an aggregate can be characterized in terms of its activation energy (E a) using the Arrhenius equation. © 2010 ASCE.

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