Print ISSN: 1813-162X

Online ISSN: 2312-7589

Volume 18, Issue 2

Volume 18, Issue 2, Spring 2011, Page 1-101


Polymeric Materials For Scale Inhibition In Cooling Water Systems

Dr.Najwa S.Majeed

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 1-11

Calcium carbonate deposition is generally predominant in cooling water-circulating system. For the control of calcium carbonate scale formation two types of polymeric scale inhibitors were used Polyamino polyether methylene phosphonate (PAPEMP)and polyacrylaminde(PAA).Model of cooling tower system have been built up in laboratory scale. Experiments were carried out using different inhibitor concentrations(0.5,1,1.5,2,3)ppm ,at water temperature of 40oC and flow rate of 150 l/hr. It was found that Polyamino polyether methylene phosphonate more effective than polyacryle amide' as scale inhibitor in all used concentrations and the best inhibition efficiency (95%) was at (2.5)ppm of Polyamino polyether methylene phosphonate and (85%) with poly acryle amide at concentrations of (3) ppm. The performance of the polymeric scale inhibitors was compared with a method used to control heavy calcium carbonate scale forming by the deposition of sufficiently thin protective calcium carbonate scale using sulfuric acid and depending on Ryznar stability index controlling method.Key words: Scale inhibitor, Cooling towers, Polymeric materials, Polyamino polyether methylene phosphonate, Polyacryle amide, Ryznar stability index, Calcium carbonate deposition.

Study of the Resonance in Series Piping Systems with Oscillating Valve

Muhammad Asmail Eleiwi

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 45-61

In This search, the phenomena of resonance in series piping systems with oscillating valve have been studied. The one-dimensional flow, unsteady state flow, and partial differential equations have been solved by using transfer matrix method. The details of the transfer matrix method, the derivation of the field matrices and point matrices, and procedures for determining the natural frequencies and frequency response of piping system are then presented. A computer program (Resonance) was developed to calculate the pressure and discharge oscillations at the valve, the phase angle between the pressure head and relative gate opening of the valve, the phase angle between the discharge and the relative gate opening of the valve and also the pressure and discharge oscillations at certain sections of the pipes. To verify the transfer matrix method, the results have been compared with impedance method and agreement has been found.Keywords:-Oscillating Valve, Series Piping, Resonance

Variable Length Cyclic Prefix OFDM Using Multipath Delay Tracking

Dr. Abdulrahman Ikram Siddiq

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 12-21

The Cyclic Prefix (CP) technique is widely used in Orthogonal Frequency Division Multiplexing (OFDM) systems. A CP of length greater than the channel order guarantees the orthogonality of the consecutive OFDM symbols. Therefore, the effects of Inter Symbol Interference (ISI) and Inter Carrier Interference (ICI) are cancelled. On the other hand, CP reduces the transmission efficiency. Conventional OFDM systems use constant length CP. For time varying channels, CP length may become shorter than channel order resulting in considerable loss in orthogonality and performance degradation. Otherwise, when CP length becomes much greater than channel order it results with time and power wasting, and hence decreasing transmission efficiency. This paper proposes the usage of a multipath delay tracking module to provide the OFDM system with the actual channel order and accordingly the suitable CP length will be determined. Computer simulations show that the proposed system saves about 47.6% of the time and power spent by the same constant length CP OFDM system tested under the same conditions.Keywords: Adaptive OFDM, Variable CP, Multipath delay tracking, AWGN.

Image Compression using Haar and Modified Haar Wavelet Transform

Musab Tahseen Salah Aldeen; Haithem Abd Al-Raheem Taha; Mohannad Abid Shehab Ahmed

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 88-101

Efficient image compression approaches can provide the best solutions to the recent growth of the data intensive and multimedia based applications. As presented in many papers the Haar matrix–based methods and wavelet analysis can be used in various areas of image processing such as edge detection, preserving, smoothing or filtering. In this paper, color image compression analysis and synthesis based on Haar and modified Haar is presented. The standard Haar wavelet transformation with N=2 is composed of a sequence of low-pass and high-pass filters, known as a filter bank, the vertical and horizontal Haar filters are composed to construct four 2-dimensional filters, such filters applied directly to the image to speed up the implementation of the Haar wavelet transform. Modified Haar technique is studied and implemented for odd based numbers i.e. (N=3 & N=5) to generate many solution sets, these sets are tested using the energy function or numerical method to get the optimum one. The Haar transform is simple, efficient in memory usage due to high zero value spread (it can use sparse principle), and exactly reversible without the edge effects as compared to DCT (Discrete Cosine Transform). The implemented Matlab simulation results prove the effectiveness of DWT (Discrete Wave Transform) algorithms based on Haar and Modified Haar techniques in attaining an efficient compression ratio (C.R), achieving higher peak signal to noise ratio (PSNR), and the resulting images are of much smoother as compared to standard JPEG especially for high C.R. A comparison between standard JPEG, Haar, and Modified Haar techniques is done finally which approves the highest capability of Modified Haar between others. Keywords: Discrete Wavelet Transform, Haar, Modified Haar, Linear Matrix Algebra, Sparse matrix

The Effect of Spark Timing on the Spark IgnitionEngine Performance

Rafeq Ahmad Khalefa

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 62-71

In this work the effect of spark timing on the spark ignition engines is investigated by computer simulation and experimental test for speeds of (1500,2000,2500,3000 and 3500)rpm at spark timing of (20o,30o,40o,50o and 60o) before TDC for each speed. This is done in order to find a suitable mathematical expression for spark ignition advancing with respect to the speed of the engine to predict the correct ignition advance as in real engines .The results showed that the method of using a mathematical expression is more realistic and reasonable comparing with the results obtained by other workers. Key words: S.I. Engine, Engine Performance, Engine Simulation, Spark Timing

Building Model for the University of Mosul Computer Network Using OPNET Simulator

Modhar A. Hammoudi

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 33-44

This paper aims at establishing a model in OPNET (Optimized Network Engineering Tool) simulator for the University of Mosul computer network. The proposed network model was made up of two routers (Cisco 2600), core switch (Cisco6509), two servers, ip 32 cloud and 37 VLANs. These VLANs were connected to the core switch using fiber optic cables (1000BaseX). Three applications were added to test the network model. These applications were FTP (File Transfer Protocol), HTTP (Hyper Text Transfer Protocol) and VoIP (Voice over Internet Protocol). The results showed that the proposed model had a positive efficiency on designing and managing the targeted network and can be used to view the data flow in it. Also, the simulation results showed that the maximum number of VoIP service users could be raised upto 5000 users when working under IP Telephony. This means that the ability to utilize VoIP service in this network can be maintained and is better when subjected to IP telephony scheme.Keywords: Computer network, Simulation, OPNET, Campus, VoIP.

Using of Fine Particle to Improvement of Sludge Dewater Ability

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 34-43

إن الهدف الرئيس من هذه الدراسة هو المقارنة بين ثلاثة بدائل استخدمت كمواد لتحسين قابلية نزع الماء من الحمأة الناتجة من أحواض الترسيب الثانوية في محطة معالجة مياه فضلات مدينة طب الموصل ، وهذه المواد هي الكاؤلين و الحجر الجيري و الحجر الطيني. استخدمت ستة جرع من هذه المواد بنسب وزنية جافة (2, 4, 6, 8, 10, 12)% من الوزن الجاف للحمأة. تم اعتماد المقاومة النوعية للحماة المعالجة كمعيار للمقارنة في تحديد المادة الأكفأ من بين البدائل المدروسة.بينت النتائج العملية إن اقل قيم للمقاومة النوعيــة للحمأة كانت 4.1× 1012، 5.9× 1012، 5.8× 1012 م/ كغم عند استخدام جرعة اضافة مقدارها 8% لكل من الكاؤلين و الحجر الجيري و الحجر الطيني على التوالي, وتبين من الدراسة ان افضل البدائل المدروسة هو الكاؤلين اذ حقق كفاءة تقليل في المقاومة النوعية للحمأة تجاوزت 70%. الكلمات الدالة: نزع الماء من الحمأة, معالجة الحمأة, المقاومة النوعية للحمأة

Verification and Generation of Safe Straight Paths for a 4-DOF Spherical Manipulator

Rawand Ehsan J.T

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 72-87

Sometimes in a manufacturing environment, a robotic arm is wanted to move in a straight path such as welding, painting and assembling. This straight path causes the manipulator to actuate all or most of its joints in the same time to track the path. Along this path, the manipulator may reach a specific singular configuration in its workspace at which one or more joints are in their limits, or a part of the path lies outside the workspace. These conditions make the arm’s movement be unsmooth and may cause damage to the manufacturing process. In this paper, the singularities inside the workspace of a 4-DOF spherical manipulator are indicated and a method is presented for finding the arm configurations (assuming that all joints are actuated at the same time) along a straight path between an initial and a goal configurations. All joint limits are presented and if a part of the path lies outside the workspace, the model processes this condition by introducing a new initial configuration through changing the third joint’s (q3) position only. A smooth straight path is generated between any two configurations using the parametric equations of the line connecting them. Unlike the analytical inverse kinematics, which needs a (4 x 4) homogeneous transformations convention matrix (DH) to find the joint variables, this method needs only the initial configuration, goal configuration, link lengths and the corresponding Cartesian coordinates of the path. It always gives the correct solution for the under taken path.Keywords: Singularity, Jacobian matrix, rank deficiency, path generation, kinematics, configuration.

Advance of Wetting Front in Silt Loam SoilUnder a Trickle Line Source

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 1-17

إن المجموعة الجذرية للنبات تتركز في بصلة الابتلال، وتطورها يتحدد بحجمه، فهو ذو تأثير كبير في نمو النبات وإنتاجيته، لذا يؤخذ بنظر الاعتبار عند تصميم منظومة ري تنقيط، سواء كان نمط الابتلال منفصلا لمنقط منفرد أو متصلا ناتجا من تداخل أنماط ابتلال لمنقطات منفردة. إن هدف الدراسة بيان تأثير الرطوبة الابتدائية للتربة والفاصلة بين مصدري تنقيط متجاورين لمعدلات مختلفة لإضافة الماء في تقدم جبهة الابتلال وتوزيع الرطوبة. شملت الدراسة 16 فحصا لمتابعة تقدم جبهة الابتلال مع الزمن, خلال طور الترطيب وطور إعادة توزيع الرطوبة, بعد إيقاف تجهيز الماء وقياسات التوزيع الرطوبي, باستخدام حالتين لمقد التربة, الأولى بمستوى رطوبة حجمية ابتدائية (4.08%), والثانية بمستوى رطوبة حجمية ابتدائية مقدارها (12.24%), وفاصلتين(25 سم و50 سم) بين المنقطين, واستخدام أربعة معدلات لإضافة الماء (0.606، 1.212, 1.818, 2.424 سم مكعب/دقيقة/سم), لتوضيح التأثير المشترك لمنقطين متجاورين بفاصلة محددة في جبهة الابتلال. اقترحت الدراسة أسلوباً لتحديد الفاصلة بين مصدري التنقيط ومعدل إضافة الماء وزمن الترطيب باعتماد منطقة ترطيب التربة ذات عمق يساوي عمق المنطقة الجذرية ويساوي كل من أقصى تقدم عمودي (شاقولي) لجبهة الابتلال تحت المنقط و أقصى تقدم عمودي (شاقولي) لجبهة الابتلال عند منتصف الفاصلة بين مصدري التنقيط. وبينت النتائج أن مقدار كل من التقدم العمودي تحت المنقط والتقدم الأفقي لجبهة الابتلال يكون أكبر في حالة المنقطين المتجاورين عنه في حالة المنقط المنفرد، كما إن التقدم العمودي لجبهة الابتلال تحت المنقط يزداد مع نقصان الفاصلة بين مصدري التنقيط، وأنّ التقدم الأفقي لجبهة الابتلال لا يتأثر بتغير الفاصلة وذلك لحالتي الرطوبة الابتدائية قيد الدراسة.الكلمات الدالة: الري بالتنقيط، جبهة الابتلال، الرطوبة الابتدائية، الفاصلة بين أنابيب التنقيط

Measurement Of Electromagnetic Field Radiation In The Internet Halls And Educational Computer Laboratories

Ghanim Thiab Hasan

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 22-32

There are more concerns about possible health effects related to electromagnetic fields from computer monitors and other video display terminals because of the widespread using of computers in laboratories ,offices and internet halls. This research aims to detect the effect of electromagnetic field radiations in these halls and laboratories and study the successful ways of minimizing its negative health effect on human health. The research has been performed on both the mathematical calculations and practical measurements. The obtaining results show that the practical measurements are consistent with the mathematical calculations results. Comparison of these results with the safety standard guideline limits shows that they are within the acceptable exposuring limits recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP ) and that means there is no health risk from exposure to these fields if the exposure is within the acceptable limits.

Dualism of Spirit-Material in Arabic Islamic Architecture

Dr. Rasheed Hameed Yaseen

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 18-33

Most of the current studies of Arabic Islamic architecture indicates different theoretical bases, whether in its definition or analyses, between different thinkers and researchers, dependable on the cultural, thoughtful and ideological bases of related references; thus, we can find Arabic Islamic architecture, both in urban planning and architectural point of view, in the light of deferent visions of: western thinkers, as an artistic forms and compositions, Arab national pioneers, analyzing its components on Arab society values, declined from its establishment of Arab desert and its impact on its rural culture; and radical Muslims thinkers restricting it on certain historical period, trying to reform it according to blocked theoretical rules, giving up its capability to development, sustainability and renewal.
The reason of all these problems is the ambiguity of the comprehensive emphasizes of one the most effective bases of Arabic Islamic architecture, which is the balance between the poles of spirit-material dualism; so that, some thinkers stood on one pole of this dualism, trying to study it through this defect point of view; meanwhile others stand on the other pole; without conscious or preconscious of the other pole, consequently the result of this hard shortage in identifying the bases of Arabic Islamic architecture in most of these studies.
This research concludes an example of Arabic Islamic cities, Samarra City, which passed on different ages, lasting from Abbasid age to modern age, reflecting different spiritual and materialistic changes according to change in political, economic, social and cultural regimes; all these indicated by the vital ruins, obviously translating these changes, where it appoints the importance of the balance between both poles of this dualism, to illustrate vision of Arabic Islamic City, through these ages

Study of Scour Downstream Different Shapes of Culverts

Ebrahem Adel Al Hafed

Tikrit Journal of Engineering Sciences, Volume 18, Issue 2, Pages 44-55

non in sandy soil beds downstream different shapes of culverts, Four shapes of culverts such as circular, ellipse, rectangular and square were used. So, a best hydraulic section was used in rectangular and ellipse shapes. The study includes the measurement and comparison of maximum scour depth and length of scour hole downstream these different shapes of culverts. Also, the distribution of soil parts was studied. It was used five discharges for each one of culvert.
Laboratory results of this study showed that the minimum depth of scour in the same discharge occurred downstream ellipse culvert and then rectangular culvert and then square culvert and the last circular culvert.