Azzaytuna University

‘Ayn al ‘Arab, Syria

Azzaytuna University

‘Ayn al ‘Arab, Syria
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Almradi A.,Azzaytuna University | Almradi A.,University of Manchester
2016 IEEE Global Communications Conference, GLOBECOM 2016 - Proceedings | Year: 2016

This paper studies the deployment of multiple- input multiple-output (MIMO) full-duplex (FD) relaying systems in a multi-cell environment, where a multi-antenna amplify-and-forward (AF) FD relay station serves multiple half-duplex (HD) multi-antenna users. The fundamental challenges of loopback self-interference (LI) and multiple co-channel interferers (CCI) at the relay and destination when incorporating FD relaying in cellular systems are addressed. Due to the higher frequency reuse in FD relaying compared to its HD relaying counterpart, the number of CCI is expected to double as the FD relay station simultaneously schedule uplink and downlink transmission on the same channel. In this paper, the optimal design of transmit/receive precoding/decoding weight vectors which maximizes the overall signal-to- interefernce-plus-noise ratio (SINR) is formulated by a proper optimization problem, then a closed-form sub-optimal solution is proposed. The proposed hop-by-hop zero-forcing (ZF) beamforming vectors are based on added ZF constraints used to suppress the LI and CCI channels at the relay and destination. To this end, new exact expressions for the outage probability and ergodic capacity are derived in closed-form. Numerical results sustained by Monte-Carlo simulations show the exactness of the proposed analytical expressions. In addition, our results show that while multi- antenna terminals improve the system performance, the detrimental effect of the number of interferers on FD relaying is clearly seen. Furthermore, our findings reveal that MIMO FD relaying could substantially boost the system performance compared to its conventional MIMO HD relaying counterpart. © 2016 IEEE.


Almradi A.,Azzaytuna University | Almradi A.,University of Manchester
2016 IEEE Global Communications Conference, GLOBECOM 2016 - Proceedings | Year: 2016

This paper analyzes the performance of information and energy beamforming in multiple-input multiple- output (MIMO) wireless communications systems, where a self-powered multi-antenna hybrid access point (AP) coordinates wireless information and power transfer (WIPT) with an energy-constrained multi-antenna user terminal (UT). The wirelessly powered UT scavenge energy from the hybrid AP radio-frequency (RF) signal in the downlink (DL) using the harvest-then-transmit protocol, then uses the harvested energy to send its information to the hybrid AP in the uplink (UL). To maximize the overall signal-to-noise ratio (SNR) as well as the harvested energy so as to mitigate the severe effects of fading and enable long-distance wireless power transfer, information and energy beamforming is investigated by steering the transmitted information and energy signals along the strongest eigenmode. To this end, exact and lower-bound expressions for the outage probability and ergodic capacity are presented in closed-form, through which the throughput of the delay- constrained and delay-tolerant transmission modes are analyzed, respectively. Numerical results sustained by Monte Carlo simulations show the exactness and tightness of the proposed analytical expressions. The impact of various parameters such as energy harvesting time, hybrid AP transmit power and the number of antennas on the system throughput is also considered. © 2016 IEEE.


Emhemmed A.S.,University of Tripoli | Ahmed N.A.,Azzaytuna University
4th International Conference on Control Engineering and Information Technology, CEIT 2016 | Year: 2017

This paper present a new design of frequency reconfigurable elevated patch antenna without using RF MEMS switch. It is well known that the patch height of the elevated patch antenna is one of the major factors in determining the antenna resonant frequency. By decreasing the patch height, the fringing fields from the patch edges will decrease, which decreases the extension in the patch length and hence the effective length of the patch, thereby increasing the resonance frequency. Therefore, the basic idea of this design is based on electrostatically adjusting the patch height to control the resonate frequency of the antenna. The measured return loss of the fabricated antenna in the up-position 0 volt, the resonant frequency of the antenna is about 189.2GHz with 18.7dB return loss. As the height of the patch reduced by applying the dc voltage, the resonant frequency shifts to 191GHz at 42volt dc voltage and with nearly the same bandwidth. © 2016 IEEE.


Elmehdi A.,Azzaytuna University | Baqar M.,Azzaytuna University | Abdalla M.,Azzaytuna University
4th International Conference on Control Engineering and Information Technology, CEIT 2016 | Year: 2017

The effect of temperature and irradiance on photovoltaic cell outputs was studied using Alternating Transient Program (ATP). A non linear current source was implemented in ATP to model a PV module under varying solar irradiance and temperature conditions. In this study, the mathematical equations were implemented and MathCad software was used to confirm the obtained results. The implemented PV module using ATP shows that increasing the temperature has negative influence on output power. On the same trend, increasing the irradiance at the constant temperature increases the power. The obtained implemented PV module model is useful for further study of stand-alone and grid-connected PV generation systems. © 2016 IEEE.


Elzlitne R.,University of Tripoli | Elhafi G.,Azzaytuna University
Journal of Advanced Veterinary and Animal Research | Year: 2016

Objective: The present study was primarily undertaken to determine the seroprevalnace of Chlamidya abortus infection in the Libyan camel (Camelus dromedarius). Materials and methods: Serological tests for C. abortus antibodies were conducted with 245 camels (205 females and 40 males) in different localities in the western region of Libya. Animals varied in age from < 1 to 20 years and were sampled randomly from both housed and nomadic herds. From each animal, 10 mL blood sample was collected and sera were separated. Antibodies in the sera against C. abortus were detected using an indirect enzyme-linked immunosorbent assay (ELISA). Results: Results of this study showed that out of the 245 camels tested for anti-chlamydia antibodies, 30 were found positive giving an overall prevalence of 12.25%. The seroprevalence of chlamydiosis was 2 folds higher in females (14.00%) as compared to males (5.00%). Conclusion: The present findings signify the C. abortus as a potential agent to cause abortion in Libyan camel (C. dromedarius). Besides, the persons who handle camels in Libya are at risk of infecting with C. abortus.


Baqar M.,Case Western Reserve University | Baqar M.,Azzaytuna University | Agag T.,Case Western Reserve University | Agag T.,Tanta University | And 4 more authors.
Macromolecules | Year: 2012

The polymerization mechanism of methylol-functional benzoxazine monomers is reported using a series of monofunctional benzoxazine monomers synthesized via a condensation reaction of ortho-, meta-, or para-methylol-phenol, aniline, and paraformaldehyde following the traditional route of benzoxazine synthesis. A phenol/aniline-type monofunctional benzoxazine monomer has been synthesized as a control. The structures of the synthesized monomers have been confirmed by 1H NMR and FT-IR. The polymerization behavior of methylol monomers is studied by DSC and shows an exothermic peak associated with condensation reaction of methylol groups and ring-opening polymerization of benzoxazine at a lower temperature range than the control monomer. The presence of methylol group accelerates the ring-opening polymerization to give the ascending order of para-, meta-, and ortho-positions in comparison to the unfunctionalized monomer. Furthermore, rheological measurements show that the position of methylol group relative to benzoxazine structure plays a significant role in accelerating the polymerization. © 2012 American Chemical Society.


Al-Habashi R.,Azzaytuna University | Abbas Z.,University Putra Malaysia
Key Engineering Materials | Year: 2013

A new developed formula named the Habashi-Zul formula, based on the Maxwell-Garnett (MG) formula was fabricated and used to calculate the complex permittivity of the Sm-YIG in PVDF composite samples in the frequency range of 10 MHz to 1 GHz. The calculated permittivities results were compared with the measured values of each sample of Sm-YIG in PVDF composite samples and, with calculated results from various theoretical models including the MG, Looyenga, Bruggeman and, Sen Scala and Cohen. The Habashi-Zule formula presented higher accuracy as compared to other models. © (2013) Trans Tech Publications, Switzerland.


Habashi R.A.,Azzaytuna University | Abbas Z.,University Putra Malaysia
Journal of Nano Research | Year: 2014

This work is concerned with the preparation of samarium iron garnet (Sm3Fe5O12) nanoparticles via an improved technique named: Modified Conventional Mixing Oxides (MCMO) method. This material was characterized by XRD, FESEM, EDX and TEM. Metal oxides and ethanol solution were used as raw materials to prepare Sm3Fe5O12 (SmIG) material. Single-phase SmIG nanoparticles with an average particle value of 25 nm and average crystallite size value of 44 nm have been synthesized at 1350 oC via the MCMO method. SmIG powders with grain sizes below 1 μm and high purity have been presented by FESEM and EDX results, respectively. Lattice constant value of 12.535 A° and density value of 6.221 g.cm-3, were calculated for the SmIG sample. The latter has reached around 99% of its theoretical density. The MCMO method appears to be an attractive route due to the enhancement of structural properties of the interested sample with high yield in the nano-scale product as compared to other preparation techniques. © (2014) Trans Tech Publications, Switzerland.


Yakhlef S.,Azzaytuna University | Hamdan M.A.,Azzaytuna University
2013 The International Conference on Technological Advances in Electrical, Electronics and Computer Engineering, TAEECE 2013 | Year: 2013

This paper studies the problems related to the location management strategies, i.e., Location Area Based, Movement Based, and Timer Based for Wireless networks. The simulation models are based on user motion and call arrival is based on Poisson arrival process. The Timer-based Location Management strategy is one in which the user updates its location periodically after an interval of time. This time is based upon the user's mobility. The scheme seeks to minimize the average signaling cost for individual mobile users for both paging and registration. In the adaptive Location Area Based strategy, the user updates its location on each Location Area (LA) call boundary crossing. In this case the LA size is adaptive changing according to the user's mobility characteristics. In the Movement Based Location strategy, the user keeps track of the number of LA calls boundary and updates when the number exceeds a predefined value. © 2013 IEEE.


Elfallagh F.A.,Azzaytuna University
Advanced Structured Materials | Year: 2014

The stresses around the Vickers indents in alumina [surface orientation ð11 _ 0 2Þ] were investigated by Cr3+ fluorescence spectroscopy, measuring the shifts in the Cr3+ R1 and R2 luminescence lines. Changes in R1 peak position can be related directly to changes in residual stress of the alumina in the sampled volume, and changes in R1 peak width arise from local stress variations due to microstructural defects such as cracks and dislocations. The intensity of the R1 and R2 fluorescence peaks was observed to decrease with increasing proximity to the indent centre due to increased scattering from residual surface and microstructural damage such as dislocations, cracks and surface debris. © Springer International Publishing Switzerland 2014.

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