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Article
Adsorption of Hexavalent Chromium Ion from Aqueous Solution by Sodium Alginate and Carboxymethyl Cellulose Beads: Kinetics and Isotherm Studies

Author: Ali J. Salim
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2015 Volume: 18 Issue: 4 Pages: 40-48
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

The removal of hexavalent chromium from aqueous solutions using biopolymeric beads of crosslinked sodium alginate (SA) and carboxymethyl cellulose (SCMC) as the adsorbent is reported in this paper. The biopolymeric alginate and carboxymethyl cellulose beads were prepared and characterized by FTIR spectra. The studies of adsorption of Cr(VI) were conducted by varying various parameters: such as contact time, pH, amount of adsorbent and concentration of adsorbate. A comparison of kinetic models applied to the adsorption of Cr(VI) ions on the adsorbents was evaluated for the pseudo-first-order, the pseudo second-order and intraparticle diffusion kinetic models respectively. Results show that the pseudo second-order kinetic model was found to correlate the experimental data well. The experimental equilibrium data were applied to Langmuir and Freundlich isotherm models and their equilibrium parameters were estimated.

في هذا البحث تم دراسة امتزاز ايون الكروم السداسي من محلوله المائي باستخدام بوليمرات حيوية محورة (صوديوم كاربوكسي مثيل سيللوز, صوديوم الجنيت) باستخدام عامل التشابك كلوريد الالمنيوم. تضمن البحث دراسة العوامل الموثرة على عملية الامتزاز: الدالة الحمضية, زمن التفاعل ,كمية المادة المازة وتركيز ايون الكروم السداسي. كذلك تم دراسة حركية امتزاز ايون الكروم السداسي باستخدام: المعادلة الحركية من الدرجة الاولى الكاذبة, المعادلة الحركية من الدرجة الثانية الكاذبة ومعادلة الانتشار بين الجسيمات حيث وجد ان الدراسة تخضع للمعادلة الحركية الكاذبة من الدرجة الثانية. كذلك تم دراسة ايزوثيرمات الامتزاز باستخدام معادلة فريندليش ولانكماير وتبين ان الامتزازلا يتبع كلا المعادلتين.


Article
Design of Compact Dual-band Antenna for 4G LTE Wireless Devices

Author: Ali J. Salim
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 6 Part (A) Engineering Pages: 1194-1206
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this paper, the planar dual-band monopole antenna is presented for Long Term Evolution (LTE) and Wireless Local Area Network (WLAN) applications. The design of the proposed antenna is based on Peano fractal curve and meander line structures. The antenna operates in 1.71 GHz to 2.01 GHz in the desired LTE frequency band and 5.0 GHz to 5.5GHz band (IEEE 802.11a band). The frequency band 1.71 - 2.01 GHz is already available as a study of the current plan according to UMTS and LTE systems (the band no.4). The antenna has been fixed on a substrate boardArlon with εr= 2.33 and thickness of 0.9 mm. Simulation results shows that the proposed antenna has promising radiation characteristics and a reasonable gain of 2.155 dBi at the lower band and 4.772 dBi at the upper band. The simulation and evaluation of antenna performance werecarried out using Microwave Studio Suite of Computer Simulation Technology CST.


Article
Design and Fabrication of Band Pass Filter (BPF) Based on Substrate Integrated Waveguide (SIW) Technology for Communication Applications

Authors: Aya Nabeel Alkhafaji --- Ali J. Salim
Journal: journal of kerbala university مجلة جامعة كربلاء ISSN: 18130410 Year: 2016 Issue: المؤتمر العلمي الرابع لكلية العلوم Pages: 186-194
Publisher: Kerbala University جامعة كربلاء

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Abstract

In this paper a new filter is constructed by embedding two semi-circular slots have been in the SIW structure for use in X-band applications. The insertion of these slots has successfully led to the compact size and the wide bandwidth. The cavity dimensions are 9.94×13.09 mm2 while the overall filter dimensions are 26.6×14 mm2 using a substrate with relative permittivity of 2.2 and thickness of 0.245 mm. The resulting structure exhibits a return loss less than -15 dB and insertion loss approaching to -0.26 dB over the passband, while a fractional bandwidth of about 68.4% centered at 11.7 GHz. An acceptable agreement between the experimental and simulation results. The compact size offered by this filter makes it a suitable for use in designing microwave circuits. The simulation and performance evaluation of the proposed filter have been carried out using Microwave Studio Suite of Computer Simulation Technology (CST).

في هذا البحث، تم تنفيذ مرشح جديد وذلك بتضمين شقوق شبه دائرية الشكل في تركيبة الـ (SIW) لغرض استخدامه في تطبيقات الـ (X-band). ان تضمين هذه الشقوق في هذا المرشح ادى الى الحصول على حجم مصغر وحزمة عريضة. ابعاد المرشح هي 13.09 × 9.94ملم مربع في حين الابعاد الكلية 14×.626 ملم مربع وذلك بإستخدام قاعدة اساس ذات سماحية نسبية 2.2 وسمك 0.254ملم. لقد اظهرت النتائج ان المرشح يتمتع بخسائر ارجاع اقل من dB 15- وخسائر داخلية تقترب من dB 0.26- على طول الحزمة والنسبة المئوية لحزمة العمل بلغت 68.4% وقيمة التردد الوسطي هي .11.7 GHz وقد تبين من خلال مقارنة النتائج العملية مع نتائج المحاكاة ان هناك تطابق تطابق مقبول جدا. ان الميزات التي وردت في اعلاه جعلت هذا المرشح ملائما للعمل في تصميم دوائر انظمة الموجات الدقيقة. ان عمليات المحاكاة وتقييم الاداء لهذا المرشح المقترح قد نفذت بأستخدام الحقيبة البرمجية المعروفة ب (MWS CST).

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Article
Design of Fractal- Based Bandstop Filter for Microwave Radiation Leakage Reduction

Authors: Ali J. Salim --- J.K. Ali --- H.S. Ahmed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 1 Part (A) Engineering Pages: 16-23
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

There is a continuing concern over the risks associated with the use of microwave ovens because of the probable effects of the radiation leakage on the health of the individuals. In this paper, a new microstrip bandstop filter BSF is presented, designed and measured as an attempt to reduce the radiation leakage from the domestic microwave ovens operating at 2.45 GHz. The proposed BSF is composed of fractal based open-loop resonators coupled with an open-stub transmission line. The open-loop resonators are in the form of modified Minkowski fractal geometry of the 1st iteration. The open stubs have been adopted to increase the selectivity of the filter stopband response. The suggested filter is designed at 2.45 GHz. Modeling and performance assessments of the proposed filter have been evaluated by means of the computer software technique CST Microwave Studio and the Sonnet EM simulator. Simulation results reveal that the modeled filter offers stopband response with high selectivity. A prototype of the proposed filter is fabricated. The size limitations of the microwave oven opening width have been taken into account. Good agreement has been found between measured and simulated results. Four arrays of such a filter have been implemented to cover the microwave oven door frame taking into consideration the opening dimensions such that it well fit it. Measured radiated electric fields from the oven show that it considerably reduces the leaked radiation. By suitable choice of substrate material and carrying out the required dimension scaling, the proposed design idea is flexible and can be generalized for use with a wide variety of microwave equipment in which microwave leakage represents a serious issue.


Article
A Compact Dual-Band BPF Based on Open Loop Resonator for Satellite Communication Applications

Authors: Ali J. Salim --- Aya N. Alkhafaji --- Mushtaq A. Alqaisy
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 9 Part (A) Engineering Pages: 997-1001
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this paper, a new filter is constructed by inserting two slots in the form of rectangular open loop resonator with folded ends. The insertion of these slots has successfully led to the compact size and the dual bandwidth behavior. The overall filter dimensions are 16×12 mm2, which correspond to 0.61λg × 0.4λg using a substrate with Rogers Ro 4003 with a relative permittivity of 3.38 and thickness of 1.0 mm. The resulting structure exhibits a dual-band behavior. The first passband has a center frequency of 6.2 GHz with FBW of 16.833% and input reflection coefficient better than -30 dB and insertion loss is approximately equal to -0.3 dB. In the second passband, the center frequency is 9.6 GHz, and the FBW is 12.57% with an input reflection coefficient better than -25 dB and insertion loss is approximately equal to -0.5 dB. The transmission zero is located between the dual passbands at 7.8 GHz with over -28.66 dB of the stopband. The simulation and performance evaluation of the proposed filter have been carried out using Microwave Studio Suite of Computer Simulation Technology (CST). As a result, this makes the proposed filter candidate for operating in satellite applications.


Article
Synthesis and Characterization of New 1,2-Dihydropyridine-3-Carbonitrile Compounds with Study of Expected Biological Activity

Authors: Hiba H.Ibraheem --- Yasameen K. Al-Majedy --- Ali J.Salim --- Redha I. Al-Bayati
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2018 Volume: 21 Issue: 2 Pages: 45-50
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

New 1,2-dihydropyridine-3-carbonitrile derivative compounds (3,4) were synthesized by cyclization of ketones (compound (1) and compound (2)) with appropriate aldehydes (4-N, N-dimethylaminobenzaldehyde and 4-chloro-2-oxo-2H-chromene-3-carbaldehyde) in presence of ethyl cyano acetate and ammonium acetate. The new synthesized compounds have been characterized using Melting point, FT-IR spectroscopy and 1H-NMR and 13C-NMR spectrum. The evaluation of biological activity of some synthesized compounds (1-4) with different concentration 10 mg mL−1, 1 mg mL−1 and 0.1 mg mL−1, against two types of bacteria on gram positive bacterial Staphylococcus aureus, Streptococcus pyogenus and gram nagetive bacterial Escherichia coli, Klebsiella pneumniae.


Article
Fabrication and Performance Evaluation of a Fractal- based Slot Printed Antenna for Dual-band Wireless Applications

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Abstract

Abstract – Different fractal geometries are successfully applied to design compact size printed and microstrip antenna structures for multiband and dual-band wireless communication applications. In this paper, a printed antenna with fractal based slot structure is presented as a candidate for use in dual-band wireless applications. The slot structure of the proposed antenna is with circle based fractal geometry. The slot structure has been etched in the ground plane of an FR4 substrate with relative dielectric constant of 4.4 and 1.6 mm thickness and on the reverse side a microstrip line has to be printed as a 50 Ω feed. Simulation results of the modeled antenna show that it offers a dual-band resonant behavior with a considerable resonant frequency ratio; covering a wide variety of wireless applications. Modeling and performance evaluation of the resulting antenna are carried out using the commercially available EM simulator HFSS, from Ansoft Corporation. A parametric study reveals that the proposed antenna offers fractional bandwidths of about 13% to 27% for the lower resonant band and 7% to 28% for the upper resonant band. The corresponding gain throughout these bands varies from 2.53 to 3.58 dB and from 4.08 to 5.76 dB respectively. This makes the antenna suitable for use in a wide variety of wireless applications. A fabricated prototype of the proposed antenna shows a return loss response which is in reasonable agreement with that theoretically predicted within the same swept frequency range. Furthermore, the proposed antenna exhibits good radiation characteristics at the resonant bands.Keywords – Fractal antenna; slot antenna; dual-band antenna; printed antenna; circle-based fractal geometry.

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