Print ISSN: 1813-162X

Online ISSN: 2312-7589

Volume 13, Issue 2

Volume 13, Issue 2, Spring 2006, Page 1-118


FINITE ELEMENT ANALYSIS OFTHICK ORTHOTROPIC SQUARE PLATES ON ELASTIC FOUNDATIONS

Dr. Adel A. Al-Azzawi; Mustafa H. Al-Allaf; Dr. Riyad J. Aziz

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 1-25

This paper deals with the linear elastic behavior of thick orthotropic square plates on Winkler type elastic foundations with both compressional and tangential resistances. The finite element method with different isoparametric thick plate and brick elements are used to solve problems, which were previously solved by the finite difference method. Good agreement is found between the different methods with percentage difference about 1%.. KEYWORDSFinite element, Orthotropic material, Thick square plates, Winkler foundations

EXPERIMENTAL STUDY THE EFFECT OF OCTANE NUMBER ON PERFORMANCE OF THE SPARK IGNITION ENGINE

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 15-29

يهدف البحث الحالي الى دراسة عملية لتأثير العدد الاوكتاني على اداء محرك الإشعال بالشرارة. شملت الدراسة نماذج من الوقود بعدد اوكتاني (90,85,80,75,70) تم تحضيرها في مختبرات البحوث والسيطرة النوعية لشركة مصافي الشمال /بيجي باستخدام محرك قياسي (CFR) . أجريت الاختبارات باستخدام محرك رباعي الأشواط نوع (TD110) أحادي الاسطوانة ذو نسبة انضغاط (1:6) مربوط الى داينموميتر هيدروليكي نوع (TD115) . لقد تبين أن استخدام الوقود ذو العدد الاوكتاني (70و75) له مشاكل في بداية التشغيل والتعجيل تمثلت في صعوبة الإدارة وتأخير فترة التسخين علاوة عل الطرق للوصول الى حالة الاستقرار. أظهرت النتائج أن هناك تحسن في معاملات الأداء للمحرك تبعا لزيادة العـدد الاوكتاني ويـبرز التحسـن واضحا عند المقارنة بين نـتائج النموذجـين ( 70و90) وكما يلي :عند سرعة 2800 دورة في الدقيقة يزداد عزم المحرك والكفاءة الحرارية المكبحية بنسبة %9.75 و%12.48على التوالي. بينما عند سرعة 3400 دورة في الدقيقة تزداد القدرة المكبحية ودرجة حرارة العادم بنسبة %8.97و%3.7 على التوالي .اما الاستهلاك النوعي المكبحي للوقود فينخفض بنسبة %15 عند سرعة 2800 دورة في الدقيقة.

MATHEMATICAL AND COMPUTER MODELS FOR THERMODYNAMIC PROPERTIES OF METHANE (R-50), ETHYLENE (R-1150) AND PROPYLENE (R-1270)

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 93-118

A set of computer methods for calculating densities, vapor pressures, enthalpies, internal energies and entropies of methane (R-50), ethylene (R-1150), and propylene (R-1270) to be described. Formulation and solution of equations for these thermodynamic properties to be presented first based on what published by ASHRAE. The data obtained from these subroutines showed very small and acceptable percentage errors when compared with ASHRAE data and what available in the literature. These results ensure that these subroutines are acceptable.KEY WORDSThermodynamic properties, hydrocarbon refrigerants

STUDY OF POSSIBILITY OF USING THE REED AS THERMAL INSULATION

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 1-14

يهدف البحث إلى توفير عازل محلي رخيص الثمن بديل للعوازل المستوردة، وقد وقع الاختيار على سيقان القصب لتوفره بكثرة ولما يحويه من فجوات هوائية يمكنها ان تلعب دورا كبيرا" في عملية العزل الحراري. تم صنع جهاز لقياس معامل التوصيل الحراري للعوازل بطريقة الصندوق. و تم تحضير عينات مختلفة السمك من سيقان القصب التي تم ربطها باستخدام الغراء الأبيض او الأسلاك المعدنية. وتم التحكم في سمك العازل عن طريق التحكم بعدد الطبقات. أجريت بعد ذلك قياسات معامل التوصيل الحراري لمديات من درجات الحرارة تراوحت بين Co(40-90) لأسماك مختلفة. تم كذلك حساب معامل التوصيل الحراري عدديا بطريقة العناصر المحددة وباستخدام برنامج ANSYS . وبمقارنة النتائج العملية مع النظرية وجد أن نسبة التوافق بينهما بلغت 90% . أثبتت النتائج أن سلوك معامل التوصيل الحراري مشابه لسائر العوازل الحرارية إذ إن قيمة معامل التوصيل الحراري تقع ضمن المدى (0.0938-0.0394) W/m.Co وبمقارنة هذه القيم بمعامل التوصيل الحراري لمادة الستايروبور التي تقع ضمن المدى (0.0433-0.0336) W/m.Co يمكن اعتبار مادة القصب واحدة من العوازل الحرارية المقبولة والواعدة بعد دراستها من الجوانب الأخرى.

INFLUENCE OF ADDING DIFFERENT FILLERS ON POLY ETHYLENE PROPERTIES

Saba A. Ghani; Dr. Abdulla Abd Al-Shakoor; Dr. Ame; r H. Majeed

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 26-38

The aim of this study was focused on the improvement of pouring, mechanical and thermal properties of high density polyethylene using chemically treated kawaline as a filler which is composed of 10% carbamide and 90% kawaline.
A composed had been made among the new filler (kawaline-carbamide), alumina and the pure kawaline in improving the latter properties of polyethylene.
It was found that all the mentioned properties affect deeply by filler type and its content. Also it was found that the suitable filler is alumina and kawaline –carrbamide in less performance.

ESTIMATION OF MISSING LEFT TURNING MOVEMENT FOR INTERSECTIONS TRAFFIC VOLUME COUNT

Mohammad Ahmad Hummody

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 39-66

Intersection traffic volume count must be in of the accurate data, because it is a crucial in the calibration and validation of traffic demand models. It is process in a continuous manner done by the analyst, planner or designer.
Many procedures were recently produced to estimate the intersection turning movement matrix. Sometimes, these procedures of traffic volume count may have unusual, unavailable or missing values especially for the left turn movement, which is more effective in capacity analysis.
Typical four mathematical and statistical methods of estimating the missing left turn movement volume were developed for about twenty signalized intersections. The most significant one is the typical curve estimation method. It is a power curve and in a simple formula compared with several other imputation techniques. This method can be superior to substitute the other methods in estimating the intersection traffic volume matrices.

THE USE OF BENTONITE CLAY AS A COAGULANT OR A COAGULANT AID WITH ALUM IN TURBIDITY REMOVAL

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 72-93

The main goal of this study is to use bentonite clay as a coagulant and coagulant aid in removing different water turbidities levels in order to improve drinking water quality at economical costs. The study showed that this material as coagulant has been proven to be efficient especially at low turbidity levels (i.e. not more than 25 ntu) with a dose of not more than 25 mg/l. As a coagulant aid with alum bentonite has shown to very effective with dose as much as 15 mg/l for low and intermediate initial turbidity level (not more than 100 ntu) and with a dose not more than 30 mg/l for high initial turbidity level 500 ntu, this efficiency is be better for low initial turbidity level and with low alum dose.

STUDY THE EFFECT OF INDUSTRIAL WASTE

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 53-71

This Research deals with the effect of industrial waste on the engineering properties of clayey soil .The investigated soil was obtained from (1.0) meter depth Al- Yarmook district in Mosul City. The soil can be described as light brown stiff clay, in organic clay with high plasticity (CH), and it contains (38%) clay size particles ( 0.002 mm). The soil was treated with four types of industrial waters, taken from several factories located in Mosul city and from fertilizers factory in Baiji region.
The Results, show that the industrial waters caused a little reduction in the liquid limit and Increased the plasticity index, except the fertilizers factors Industrial waters where plasticity index of the soil decrease with increasing the addition of this type of industrial waters. As far as the effect of industrial waters on the compaction characteristics, the result showed that the maximum dry density of the soil increased with the addition of industrial waters and the optimum moisture content decreased.
The industrial waters increased the unconfined compressive strength and the shear strength parameters (angle of internal friction ( ) and cohesion (c')) , except the industrial waters from sugar and yeast factories decreased the angle of internal friction .
The study, showed that the swelling percentage and swelling pressure increased with increasing the concentration of industrial waters, except the industrial waters of the fertilizers factory, where the swelling characteristics decreased.
The results of consolidation test showed that the compression Index (cc) and coefficient of consolidation (cv) increased when the soil was treated with industrial waters.
The results of chemical tests showed that the values of cat ion exchange capacity and organic matter content increased while the (pH- value) decreased for treated soil, except the Industrial waters of fertilizers factory, which caused an increase in the (pH-value) .

CURVATURE DUCTILITYOF REINFORCED CONCRETE COLUMN SECTIONS UNDER DIFFERENT STRAIN RATES

Dr. Raad K. Al Azawi; Dr. Thamir K. Al-Azawi

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 67-92

This paper presents theoretical parametric study of the curvature ductility capacity for reinforced concrete column sections. The study considers the behavior of concrete and reinforcing steel under different strain rates. A computer program has been written to compute the curvature ductility taking into account the spalling in concrete cover. Strain rate sensitive constitutive models of steel and concrete were used for predicting the moment-curvature relationship of reinforced concrete columns at different rate of straining. The study parameters are the yield strength of main reinforcement, yield strength of transverse reinforcement, compressive strength of concrete, spacing of ties and the axial load. The results indicated that higher strain rates improve both the curvature ductility and the moment capacity of reinforced concrete column sections.

EFFECT OF MATERIALS THAT COMPONENT THE CONCRETE MIXTURES USED IN SALAH AL- DAIN PROJECTS ON THE COMPRESSIVE STRENGTH

Dr. Jawdat Kadhim Abbas; Yassen Ali Salh

Tikrit Journal of Engineering Sciences, Volume 13, Issue 2, Pages 30-52

In this research, (192) concrete cubes were taken from different concrete mixtures incorporating coarse and fine aggregate from four different sources in Salah Al-Dain area with two types of cement; Iraqi cement & Turkish cement. The compressive strength of these cubes was examined to know the most suitable materials to product good concrete for use in the projects of Salah Al-Dain area. The results indicate that, the aggregate brings from Al-Tuz source gives compressive strength higher than the aggregate brings from other sources. The Turkish cement gives compressive strength higher that that gives by Iraqi cement.