Print ISSN: 1813-162X

Online ISSN: 2312-7589

Volume 17, Issue 3

Volume 17, Issue 3, Summer 2010, Page 1-73

Magnetic Circuit & Torque Analysis Of Brushless DC Motor

Mohamed Rashide; Kais Wadi; Dr . Arif J. Abass

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 1-12

This work is concerned with magnetic and torque analysis of BLDCM and with development of a method of designing BLDCM that have symmetric winding on the rotor .make significant contribution to the rotor inductance position difficult. It is also show that the prediction detent torque can be extremely sensitive to the permanent magnet by altering magnet arc width. Finally, simple lumped models that allow one to predict motor performance and characteristics as a function of main dimension, magnet residual flux density and phase current are developed. These models are used as a basis for an approach to designing BLDCM.Keywords:Rotor construction, , Armature windings, Equivalent circuit, Torque analysis.

Study of the Effect of Reinforced Glass Fibers on Fatigue Properties for Composite Materials

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 15-24

يتضمن البحث دراسة تأثير تدعيم الألياف الزجاجية في خصائص الكلل للمواد المتراكبة إذ تم استخدام رانتج البوليستر كمادة رابطة لنوعين من الألياف لغرض التدعيم هما : النوع الأول هو الألياف الزجاجية المتضمنة ذات اتجاه (0-90) اما النوع الثاني فهو الألياف الزجاجية عشوائية الاتجاه. صنعت الألواح من المتراكبات. كما تم تقطيع الألواح إلى عينات لغرض أعدادها للفحص وفقا لمواصفات الجهاز المستخدم كالأتي:(1-2) طبقة من الألياف المنتظمة (0-90), و(1-2) طبقة من الألياف العشوائية وذلك لفحص تأثير زيادة عدد الطبقات في خاصية الكلل. وقد تبين ان عدد الدورات يقل عند زيادة عدد طبقات التسليح الى حد الكلال بالنسبة للعينات المسلحة,و ان عدد الدورات الى حد الكلال يقل بالنسبة للعينات ذات الطبقتين من التسليح العشوائي ((random مقارنة مع العينات ذات الطبقة الواحدة,وان المرونة واجهاد اللي يتأثران بأزدياد عدد الطبقات.

Carbon Dioxide Absorption in Packed Column inNon-Newtonian Fluid

Fadhil Hashim Farje; Alyaa Khadhier Mageed; Dr.Farah Talib Jasim

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 13-21

Absorption of carbon dioxide into carbonate solution (Na2CO3) with PAM (non-Newtonian fluid) has been performed in a countercurrent packed column (0.075m i.d. *1.25 m height) packed with glass Raschig rings ( 1*1cm) to a depth of 1m. The influence of liquid flow rate, gas flow rate, liquid temperature, and polyacrylamind (PAM) concentration on the absorption rate, overall mass transfer coefficient and the reaction kinetics regime are studied at constant carbonate concentration and atmospheric pressure. The results show that the absorption rate and overall mass transfer coefficient increases with increasing liquid flow rate and temperature. The mass transfer coefficient decreases with increasing gas flow rate while the absorption rate of carbon dioxide is virtually independent of gas flow rate. This indicates that carbon dioxide absorption is liquid film controlled. Increasing PAM concentration results of reduction of absorption rate and overall mass transfer coefficient. The reaction kinetics between carbon dioxide and carbonate solution with PAM was obtained as a pseudo first order reaction (Hatta number ,Ha >>1).Keywords: carbon dioxide absorption, non-Newtonian fluid, mass transfer

Tendons Arrangement Effects on Reinforced Concrete FramesUnder Blast Loading

Ayad B. Bahnam

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 22-30

The tendons arrangement effects on the response of reinforced concrete frame experiencing blast loads is investigated in this paper. The structure is modelled using nonlinear finite elements employing a bilinear hysteretic model. So that elements are used so that yielding of the structures could be accurately modelled and captured. The frame is analyzed using a non-linear, elastic-plastic finite element program written in code MATLAB. Six tendon architectures were investigated. A single tendon was placed between different floors and its effects investigated. From the obtained results, the ideal case which causes a reduction in the maximum displacement and the amount of permanent deflection without increase in the maximum structural shear forces greatly is obtained.Keywords:Tendon arrangement, Reinforced concrete, Blast loading, Finite elements.

Optimal Design of Round Bottomed Triangle Channels

Ayman T. Hameed

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 31-42

In optimal design concept, the geometric dimensions of a channel cross-section are determined in a manner to minimize the total construction costs. The Direct search optimization method by using MATALAB is used to solve the resulting channel optimization models for a specified flow rate, roughness coefficient and longitudinal slope. The developed optimization models are applied to design the round bottomed triangle channel and trapezoidal channels to convey a given design flow considering various design scenarios However, it also can be extended to other shapes of channels. This method optimizes the total construction cost by minimizing the cross-sectional area and wetted perimeter per unit length of the channel. In the present study, it is shown that for all values of side slope, the total construction cost in the round bottomed triangle cross-section are less than those of trapezoidal cross-section for the same values of discharge. This indicates that less excavation and a lining are involved and therefore implies that the round bottomed triangle cross-section is more economical than trapezoidal cross-section.Keywords: Open channels; Optimization; Effective cost; Channel design; Direct search.

Kinetics of Sulfur, Vanadium and Nickel Removal from Basra Crude Oil Hydro Treating

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 1-14

تم معاملة نفط خام البصرة كاملاً بالهيدروجين في مفاعل ثلاثي ألأطوار باستخدام الكوبلت مولبيدنيوم المحمول على ألألومينا كعامل مساعد. كانت حدود درجات حرارة التفاعل للنفط الخام بين 598 و 648 كلفن وحدود سرع السائل الفراغية من 0.7 الى 2 ساعة-1 وكانت هذه التفاعلات تحت ضغط هيدروجيني ثابت مقداره 3 ميكاباسكال وباستعمال نسبة هيدروجين الى المغـــذي مقدارها 300 لتر/لتر . درست حركية تفاعلات إزالة الكبريت والفناديوم والنيكل وقد وُجد ان الحركية الظاهرة لتفاعل إزالة الكبريت هي من الدرجة ألأولى والحركية الظاهرة لتفاعل إزالة الفناديوم والنيكل هي من الدرجة الثانية . تم حساب طاقات التنشيط الظاهرية فكانت 24.03 و75.86 و63.90 كيلوجول/مول لتفاعلات إزالة الكبريت والفناديوم والنيكل لنفط خام البصرة المعامل بالهيدروجين على التوالي .الكلمات الدالة :حركية ازالة الكبريت خلال المعاملة الهيدروجينية ، المفاعل ثلاثي ألأطوار ، حركية ازالة المعادن خلال عملية الهدرجة

Modeling Of Ballistic Missile DynamicsIn Pitch Plane And It's Stability

Salih Mahmoud Attiya

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 68-73

Aerodynamic modeling of ballistic missile in pitch plane is performed and the open-loop transfer function related to the jet deflector angle as input and pitch rate, normal acceleration as output has been derived with certain acceptable assumptions. For typical values of ballistic missile parameters such as mass, velocity, altitude, moment of inertia, thrust, moment and lift coefficient show that, the step time response and frequency response of the missile is unstable. The steady state gain, damping ratio and undamped natural frequency depend on the missile parameters. To stabilize the missile a lead compensator must be added to the forward loop.

Simulation and Evaluation of Ethernet Passive Optical Network

Salah A. Jaro Alabady

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 43-57

This paper studies simulation and evaluation of Ethernet Passive Optical Network (EPON) system, IEEE802.3ah based OPTISM 3.6 simulation program. The simulation program is used in this paper to build a typical ethernet passive optical network, and to evaluate the network performance when using the (1580,1625)nm wavelength instead of (1310,1490)nm that used in Optical Line Terminal (OLT) and Optical Network Units (ONU's) in system architecture of ethernet passive optical network at different bit rate and different fiber optic length. The results showed enhancement in network performance by increase the number of nodes (subscribers) connected to the network, increase the transmission distance, reduces the received power and reduces the Bit Error Rate (BER).Keywords: Optical Communications, Optical Networks, Passive Optical Network .

The Effect of Using Insulation on the Energy Saving in Building

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 25-38

تهدف الدراسة الحالية تحليل الأداء الحراري لبناية بحجم600 م3 مبنية وفق ثلاثة نماذج. بناء الجدران في النموذج الأول بالطابوق أما في النموذج الثاني فالجدران فيه مقسمة الى قسمين تفصلهما طبقة من مادة البولي ستايرين بسمك 4 سم والسقف مغطى بهذه المادة من الخارج بنفس السمك في حين تتكون الجدران في النموذج الثالث من جزئيين وتفصلهما فجوة هوائية بعرض 8 سم مع استخدام سقف ثانوي. تم اعداد برنامج بلغةQbasic لحل المعادلات الرياضية عدديا" باستخدام طريقة الفروقات الحدية وفي الظروف الجوية لمدينة بغداد لشهر كانون الثاني لسنة 1994. تبين من نتائج المحاكاة ان نسبة توفير الطاقة من قبل النموذجين الثاني والثالث بالمقارنة مع النموذج الأول هي 29.96% و 35.40% على التوالي. الكلمات الدالة: انتقال الحرارة من المباني، توفير الطاقة

A Study of Horizontal Displacement of Laterally Loaded PilesUsing Finite Element Method

Aram M. Raheem

Tikrit Journal of Engineering Sciences, Volume 17, Issue 3, Pages 58-67

A theoretical approach is used to analyze single pile and pile in group under lateral loading using two programs. The first one used the finite element method for single pile depending on plain strain condition while the second one used the characteristic load method for pile in group. Horizontal displacement for pile in group is measured while both horizontal displacement and shear stress for single pile are measured. A comparison between the results of horizontal displacement for both single pile and pile in group with the actual practical values are produced and shows a good agreement.Keywords: lateral loading, pile, horizontal displacement, pile group.