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Article
A PARTICULAR SOLUTION OF THE TWO AND THREE DIMENSIONAL TRANSIENT DIFFUSION EQUATIONS

Author: Adel Al-Hemiri عادل احمد عوض
Journal: Iraqi Journal of Chemical and Petroleum Engineering المجلة العراقية للهندسة الكيمياوية وهندسة النفط ISSN: 19974884/E26180707 Year: 2011 Volume: 12 Issue: 2 Pages: 18-20
Publisher: Baghdad University جامعة بغداد

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Abstract

A particular solution of the two and three dimensional unsteady state thermal or mass diffusion equation is obtained by introducing a combination of variables of the form,η = (x+y) / √ct , and η = (x+y+z) / √ct, for two and three dimensional equationsrespectively. And the corresponding solutions are,θ t,x,y = θ0 erfc x+y√8ct and θ t,x,y,z =θ0 erfc ( x+y+z√12ct)


Article
Prediction of Three Dimensiomal Natural Convection from a Horzontal Isothermal Square Plante

Author: Ayad K. Hassan
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2006 Volume: 12 Issue: 3 Pages: 742-755
Publisher: Baghdad University جامعة بغداد

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Abstract

A theoretical study of a three-dimensional natural convection heat transfer from an isothermal horizontal square plate, with upper and lower heated surfaces is present. The transient Navier–Stokes and energy equations were solved by using finite deference method (F.D.M). The complete Navier–Stokes equations are transformed and expressed in terms of vorticity–vector potential and solved using an Alternating Direction Implicit (ADI) method for the parabolic portion of the problem, and Successive Over–Relaxation (SOR) method for the elliptic portion .A computer program in (FORTRAN 77) was built to carry out the solution. The numerical results were obtained for laminar flow range of Grashof number up to (10^5) in up ward–facing and downward–facing with Prandtl number of (0.72). The results of local Nusselt number have maximum values at the outer edge of plate for two cases upward and downward facing heating. The comparison of the results of average Nusselt number with numerical data for downward facing and experimental data for upward facing shows acceptable agreement. It may be noted that the present data are generally different with experimental data, since the available data are extrapolated to high Grashof number. Thus the deviation may be large with present data.

يقدم هذا البحث دراسة نظرية لانتقال الحرارة ثلاثي الابعاد للحمل الطبيعي من صفيحةمربعةبوضع افقي تكون مسخنة من الاعلى والاسفل .تتضمن الدراسة الحل العددي لمعادلة الزخم والطاقة الانتقالية باستخدام طريقة الفروق المحددة .معادلة الزخم الكاملة تم تحويلها والتعبير عنها بدلالة الدوامية _متجه دالة الانسياب . المعادلات المحولة تم حلها باستخدام طريقة الاتجاه الضمني للجزء القطعي مكافئ من المسالة وطريقة فوق التراخي للجزء البيضوي .تم بناء برنامج بلغة فورتران 77لتنفيذ الحل العددي ,الذي يغطي الصحيفة مسخنة للاسفل مربعة الشكلة افقية .النتائج العددية التي تم الحصول عليهاضمن الجريان الطبقي الى حد رقم كراشوف 5^10مع رقم برانتل(0.75).رقم نسلت الموضعي تكون اعلى قيمة له عند الحافة للصفيحة للحالتين الوجه المسخن للاعلى والاسفل.تم مقارنة النتائج الحالية لرقم نسلت المعدل مع نتائج عددية وكذلك لحالة الصفيحة الوجه المسخن للاسفل وكان هناك توافق بين النتائج .وكذلك مقارنة النتائج للبحث الحالي للحالة الصفيحة الوجه المسخن الى الاعلى مع نتائج عددية وعملية نلاحظ هناك توافق في النتائج العددية وهناك فارق في النتائج العملية.


Article
An Investigation Into Three Dimensional Turbulent Flow Of Newtonian Liquid In Stirred Tanks Mixer

Authors: Nizar Jawad Hadi --- Ihsan Y. Hussian
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2010 Volume: 16 Issue: 1 Pages: 4653-4672
Publisher: Baghdad University جامعة بغداد

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Abstract

The present work is concerned with the theoretical and experimental investigation of flow pattern of Newtonian fluid in liquid mixing process in stirred tank with flat blade impeller. A three-dimensional model for mixing process was simulated. The effected parameters are rotation speed and impeller diameter. Continuity, momentum, and turbulent equations were solved by ANSYS package software 5.4 code with FLOTRAN/CFD based on Finite Element method. In the experimental work, two visualization methods are used in this work, the first method is the acid-base reaction visualization method and the second is the particle distribution visualization method. Different chemical materials were used in the first method,H2SO4 as a base,NaOH .Different chemical materials were used in the first method, Methyl red as indicator, while polymer particles were used in the second method. The results of 3D model showed that the speed rotation directly affected the mixing zones, where the speed reduction by half decreasing the mixing zones approximately by half. Also the impeller diameter increasing clearly affected the mixing process where the mixing zones concentrated directly above and below the impeller. In the experimental work, the acid-base reaction visualization method showed that the mixing zones decreased due to the rotation speed reduction depend on the red and yellow colors, which describe the good mixing and poor mixing zones respectively. The mixing zones were concentrated directly above and below the impeller due to the impeller diameter increasing,. The particles distribution method showed that the mixing zones decreased due to the speed reduction, while the mixing zones concentrated directly above and below the impeller due to the impeller diameter increasing. The results showed a good agreement between the theoretical and experimental works in studying the effect of rotating speed, and impeller diameter .

هذا البحث يتعلق بالدراسة العملية والنظرية لجريان سائل نيوتيوني أثناء عملية خلطه باستخدام تأثير عوامل مختلفة في خزان يدور فيه السائل بواسطة ريشة مسطحة. تصميم ثلاثي الأبعاد لعملية الخلط تمت محاكاته في هذا البحث. العوامل المؤثرة التي استخدمت في التصميم ثلاثي الأبعاد هي السرعة ألد ورانية، قطر الريشة. معادلة الاستمرارية، الزخم، والاضطراب تم حلها بواسطة Ansys package FLOTRAN/CFD والتي استندت إلى طريقة العناصر المحددة F .E. method. في الجانب العملي من البحث ، طريقتان لتصوير جريان السائل استخدمت في هذا البحث الطريقة الأولى هي طريقة تصوير تفاعل الحامض مع القاعدة والثانية هي طريقة تصوير توزيع الجزيئات. مواد كيميائية مختلفة استخدمت في الطريقة الأولى هيدروكسيد الصوديوم NAOH كقاعدة، حامض الكبريتيك H2SO4 كحامض، والمثيل الأحمر Methely red ككاشف بينما جزيئات بلاستيكية استخدمت في الطريقة الثانية .النتائج للتصميم ثلاثي الأبعاد أظهرت إن السرعة ألد ورانية أثرت بشكل مباشر على مناطق الخلط حيث أن تقليل السرعة إلى النصف أدى إلى تقليل مناطق الخلط تقريبا إلى النصف وبشكل واضح زيادة القطر أثرت على عملية الخلط. في الجانب العملي طريقة تصوير تفاعل الحامض مع القاعدة أظهرت إن مناطق الخلط قلت بسبب نقصان السرعة ألد ورانية اعتمادا على توزيع الألوان الأصفر والأحمر والتي توصف مناطق الخلط الجيدة والغير جيدة على التوالي. مناطق الخلط تتركز مباشرة فوق وتحت الريشة بسبب زيادة القطر. طريقة توزيع الجزيئات أظهرت إن مناطق الخلط تقل نتيجة لتقليل السرعة الدورانية، بينما تتركز فوق وتحت الريشة بسبب زيادة القطر . النتائج أظهرت توافق جيد بين الجانب النظري و العملي في دراسة تأثير السرعة ألد ورانية و قطر الريشة.


Article
Influence of occlusal schemes on the stress distribution in upper complete denture in centric and eccentric relation

Author: A bdalbasit A. Fatihallah عبد الباسط فتح الله
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2005 Volume: 17 Issue: 2 Pages: 17-20
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: This study was aimed to identify the sites of maximum stresses in both balanced and lingualized occlusion in centric and eccentric relationMaterials and Methods: Two sets of complete denture constructed and a load of 60 N applied to sites of occlusal contacts so the Von-mises stresses produced from this load applied collected.Results: Balanced and lingualized occlusal schemes compared in centric and eccentric relation, both mean and standard deviation for the calculated stresses compared at the crest of the ridge, buccal flange and mid-palatal suture.Conclusion: Both balanced and lingualized occlusion transmit minimal pressure at the mid-palatal suture and with the concentration of stresses at the crest of ridge in centric, while at the working side balanced occlusion produced greater pressure than lingualized scheme and at balancing side vice versa occur.


Article
Accuracy and precision of a photographic system for the three-dimensional study of facial morphology

Authors: Shwan E Abdulkareem شوان عبد الكريم --- Nagham Al-Mothaffar نغم المظفر
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 1 Pages: 138-145
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Facial analysis is vital for orthodontic treatment planning but traditional methods of facial analysis areincapable of fully capturing the three-dimensional complexity of the human face. The purpose of this study was todetermine the precision and accuracy of facial anthropometric measurements obtained through low-cost digitalthree-dimensional photogrammetry system.Materials and methods: Eighteen standard craniofacial measurements were obtained from faces of thirty youngadults using two methods: calipers and 3D photos (obtained with a Photomodeler system). After markinganthropometric landmarks on the faces of the sample, direct measurements were taken using calipers then fivephotographs were taken at different angles and 3D model constructed and the same measurement were takenusing Photomodeler. Differences between two methods were calculated. To test the precision of the newphotogrammetric system, measurements were repeated on the same photographs by the researcher and then byanother examiner and also a new set of photographs were taken for each individual and measurements were doneon them. Three different precision estimates were calculated to measure random error for the new method.Results: Systematic errors between the two methods were found for seven measurements but most mean differenceswere clinically insignificant (below 2 mm). In terms of measurement precision, no systematic biases were foundbetween repeated measurements on the same photographs or on different photographs and our precisionestimates showed a clinically acceptable level of repeatability for the Photomodeler system.Conclusion: It can be concluded that Photomodeler 3D photogrammetry system can provide accurate and reliablefacial measurements. It is relatively fast and requires only inexpensive equipment


Article
Three-dimensional ultrasound in evaluation of fetal brain anomalies
الموجات فوق الصوتية ثلاثية الأبعاد في تقييم تشوهات دماغ الجنين

Author: Salwa Ahmed Amin AL-Najjar
Journal: Zanco Journal of Medical Sciences مجلة زانكو للعلوم الطبية ISSN: 19955588/19955596 Year: 2016 Volume: 20 Issue: 3 Pages: 1490-1496
Publisher: Hawler Medical Univeristy جامعة هولير الطبية

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Abstract

Background and objective: Prenatal diagnosis of central nervous system anomalies by two-dimensional sonography is challenging because of difficulties in obtaining complete visualization of the fetal brain during routine examinations. Three-dimensional sonography has been introduced as a tool for studying the fetal central nervous system because of its ability to facilitate examinations of the fetal brain. This study aimed to visualize an intracranial structure of the fetal central nervous system anomaly using transabdominal three-dimensional sonography.Methods: A prospective cross–sectional (observational) study in which three-dimensional ultrasound examination was performed in 82 patients between 12 and 38 weeks of gestation suspected to have fetal brain malformation detected by conventional two-dimensional ultrasound. Each anomaly was reviewed again to determine whether three-dimensional ultrasound data were advantageous compared to two-dimensional ultrasound. Results: Three-dimensional images provided additional information in 43 (52.4%) of cases including extracerebral anomalies. The three-dimensional ultrasound was advantageous in evaluating the encephaloceles (10 of 43 cases) in that the exact location of the extracranial mass and the amount of extracranial tissue in the encephalocele was better defined with the simultaneous display of three orthogonal planes images that could not be obtained with two-dimensional ultrasound were seen with three-dimensional ultrasound.Conclusion: Three-dimensional ultrasound is an excellent adjunctive tool to two-dimensional ultrasound in the evaluation of fetal anomalies


Article
Three dimensional cephalometric measurements of craniofacial skeleton of adolescent with Class I normal occlusion in Mosul City

Authors: Khidair A Salman --- Saba H Al–Zubaidi
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2004 Volume: 4 Issue: 4 Pages: 150-156
Publisher: Mosul University جامعة الموصل

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Abstract

The aims of the present study were to establish the cephalometric craniofacial skeletal norms of Iraqi adolescents by means of linear and angular analyses of postero–anterior and lateral cephalometric radiographs and to reveal any correlation between the variables measured. The sample consisted of 101 Iraqi adolescents (52 males and 49 females) aged 12–15 years with Class I normal occlusion. Postero–anterior and lateral cephalometric radiographs were taken for each adolescent, and twenty cephalometric radiographic measurements (6 angular, 10 linear and 4 ratio) were determined. Skeletal comparison between males and females showed that the angle of palatal plane inclination in relation to anterior cranial base (SN–PP) was significantly higher in females whereas the gonial angle (ArGoMe) was significantly higher in males. For linear measurements, mandibular base length (Go–Gn) showed no significant sex differences. The remaining linear measure-ments showed significant sex differences with the males having higher values. All ratios showed no significant differences between males and females.


Article
Numerical Study for a Three Dimensional Laminar Natural Convection Heat Transfer from an Isothermal Heated Horizontal and Inclined Square Plate and With a Circular Hole

Authors: Ikhlase M.Fayed --- Yasmeen Hameed Abd
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2007 Volume: 13 Issue: 2 Pages: 1519-1538
Publisher: Baghdad University جامعة بغداد

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Abstract

A theoretical study for a three-dimensional natural convection heat transfer from an isothermal horizontal , vertical and inclined heated square flat plates (with and without circular hole) has been done in the present work. The study involved the numerical solution of the transient Navier-Stokes and energy equations by using finite deference method (F.D.M.). The complete Navier-Stokes equation are transformed and expressed in terms of vorticity-vector potential. The Energy and Vorticity equations were solved by using an Alternating Direction Implicit (ADI) method because they are transient equations of parabolic portion, and the Vector potential is solved by using an equations Successive Over-Relaxation (S.O.R) method because it is from elliptic portion. The numerical solution is capable of calculating the Vector potential, three components of Vorticity and temperature field of the calculation domain. The numerical results were obtained in rang of Grashof number (10^3≤Gr≤5x10^4) with Prandtl number of (0.72) for square flat plate and the other consist a circle hole with ratio 0.6 and 0.8 diameter of the hole to main square side length. The numerical results showed that the main process of heat transfer is conduction for Grashof number less than 10^3 and convection for Grashof number larger than 10^3 and the results of local Nusselt number show fairly large dependence on inclination angle. For horizontal plate facing upward and downward, average Nusselt number is proportional to one-fifth power of Rayleigh number, and there is a significant difference in heat transfer rates between the upward and downward cases. For horizontal plate with circle hole facing upward for Grashof number 10^4, the effect of core portion caused a limited increment in the heat transfer rate, where as for the facing downward case, the effect was larger and the maximum value of heat transfer rates is be for square flat plate with circle hole by ratio 0.6 for all inclination angles. With the increase of Grashof number to 5x104 heat transfer rates decrease except the square horizontal flat plate with circle hole by ratio 0.6 . The average Nusselt number increases with the increase of inclination of plates facing upward to reach to the higher average Nusselt number at vertical position then decrease with increase of inclination of plates. And the maximum value of average Nusselt number is depended on the ratio of diameter of the hole to main square side length, showed that the maximum temperature gradient occurs at the external edge of the horizontal plate (with and without circle hole) facing upward and at the lower external edge in inclined case. The numerical results was made through comparison with a previous numerical and experimental work, the agreement was good.

يقدم هذا البحث دراسة نظرية لانتقال الحرارة ثلاثي الأبعاد للحمل الحر من صفيحة مربعة و أخرى ذات ثقب دائري أفقية و عمودية و مائلة عن الأفق مسخنة بثبوت درجة الحرارة. تضمنت الدراسة ، الحل العددي لمعادلات الزخم الكاملة والطاقة الانتقالية باستخدام طريقة الفروق المحددة . معادلات الزخم الكاملة تم تحويلها والتعبير عنها بدلالة الدوامية و متجه الجهد الكامن. تم حـل كل من معادلة الطاقة و معادلة دالة نقل الدواميـة باستخدام طريقة(الاتجاه المتناوب الضمني)، وذلك لكونها معادلات انتقالية من نوع القطع المكافئ، و حل معادلة متجه الجهد الكامن بطريقة فوق التراخي المتعاقبة لكونها معادلات من نوع قطع ناقص. يتضمن الحل العددي حساب كل من متجه الجهد الكامن والمركبات الثلاث للدوامية ودرجة الحرارة لمنطقة الحساب. النتائج التي حصل عليها لحدود رقم كراشوف(Gr ≤ 5x10^4 ≥) مع رقم براندتل(0.72) للصفيحة المربعة و الصفيحة المثقبة بنسبة قطر الثقب الدائري إلى طول ضلع الصفيحة المربعة مساوٍ إلى 0.6و 0.8 .بينت النتائج العددية إن العملية الرئيسية لانتقال الحرارة هي التوصيل لرقم كراشوف 10^3 والحمل لرقم كراشوف أعلى من 10^3 و إن رقم نسلت الموضعي يعتمد كليا على زاوية الميلان. في حالة الصفيحة الأفقية وجهها المسخن إلى الأعلى والأسفل، متوسط رقم نسلت يتناسب مع رقم رالي للأس (5/1)، كذلك هنالك اختلاف واضح في معدلات انتقال الحرارة بين الوضع الأفقي الموجه للأعلى والأسفل. يسبب تأثير قطر الثقب لرقم كراشوف 10^4 زيادة محدودة في معدلات انتقال الحرارة في حالة الصفيحة المثقبة وجهها المسخن إلى الأعلى بينما تكون اكثر تأثيرا في حالة الصفيحة المثقبة وجهها المسخن إلى الأسفل و ان أقصى قيمة لمعدل انتقال الحرارة تكون للصفيحة المربعة المثقبة بنسبة تثقيب 0.6 و لزوايا الميل المختلفة. بزيادة رقم كراشوف إلى 5x10^4 يقل معدل انتقال الحرارة ما عدا الصفيحة المربعة الأفقية وجهها المسخن إلى الأسفل حيث يكون أقصى قيمة عند نسبة تثقيب 0.6 . تزداد قيم متوسط رقم نسلت بزيادة زاوية ميل الصفيحة المربعة وجهها المسخن إلى الأعلى لتصل إلى أعلى قيمة لها عند الوضع العمودي وبعدها تقل بزيادة ميلان الصفيحة، و إن أقصى قيمة لمتوسط رقم نسلت تعتمد على نسبة التثقيب، و إن أقصى انحدار لدرجة الحرارة يكون عند الحافة الخارجية للصفيحة المربعة و المثقبة الأفقية المسخنة إلى الأعلى و عند الحافة السفلى الخارجية في حالة الميلان . تم مقارنة نتائج الدراسة الحالية مع نتائج عددية و عملية لدراسات سابقة و كان التوافق بينها جيد .


Article
Numerical Investigation intoVelocity and Temperature Fields Over Smooth and Rough Ducts for Several Types of Turbulators

Authors: Sabah Tarik Ahmed --- Waheed S. Mohammed --- Laith J.H
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2007 Volume: 25 Issue: 10 Pages: 1110-1127
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Numerical study on a laminar and turbulent fluid flow andtemperature distribution in a rectangular duct with six types of vortexgenerators has been carried out. A modified version of ESCEAT threedimensioncode has been used to solve Navier-Stokes and energy equations.The effect of vortex generator type, geometrical configuration, anddimensions on flow and temperature in different planes has been presented.The purpose of the present investigation is to highlight the complex threedimensionalinteraction of the vortices generated by wings and other vortexgenerators to understand how such vortices configurations structure thevelocity and temperature fields. Experiment in terms of velocities andtemperatures vectors and contours were performed on 6 configurations,which experiments are (fin, fence, rib, wing-type, rectangular-type, andwinglet-type) vortex generators The results show good agreement withpublished data.

تم إجراء دراس ة عددية على توزيع الجريان ودرجة الحرارة للمائع لحالتي الجريانالطباقي والاضطرابي داخل ق نوات مستطيلة حاوية على ستة أنواع من مولدات الدوامات .بثلاثة أبعاد لحل معادلتي نفير–ستوك (ESCEAT) واستخدم لذلك نسخة مطورة من برنامجوالطاقة. حيث تم دراسة تأثير نوع مولد الدوامات وشكله الهندسي وأبعاده على الجريانودرجة الحرارة في مختلف المستويات . ان الغرض من البحث الحالي هو لتسليط الضوء علىومولدات الدوامات (wings) التأثير المعقد ذو الثلاثة أبعاد للدوامات المتولدة بواسطة الجنيحاتالأخرى لفهم كيف ان الأشكال الهند سية لهذه الدوامات تُشّ كل مجالي السرعة ودرجة الحرارة .لقد أخذت النتائج بصيغة متجهات وكنتورات (منحنيات مقفلة ) للسرع ودرج ات الحرارة لستةوجنيح (rib) والنتوء (fence) والحاجز (fin) أشكال من مولدات الدوامة وهي الزعنفةوقد أثبتت النتائج توافق . (winglet) وعائق نو ع (rectangular) وعائق مستطيل (wing)وتطابق جيد مع تلك المنشورة سابقاً.


Article
Finite Element Analysis of Fire Extinguisher for Different Types of Composite Materials

Author: Raed Naeem Hwyyin
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2011 Volume: 29 Issue: 13 Pages: 2617-2636
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The stress and strain concentrations of a fire extinguisher made of different types of composite materials are investigated. The prediction of the failure limit and its location in the proposed design is always the associated problem that is inescapable and difficult to be solved completely in the shape design of pressure vessel. A three dimensional analysis in finite element method was made for determining theconcentration of stress and strain of the extinguisher. The xtinguisher is made of polyester resin reinforced with different types of fiber glass. The aim of the present investigation is to study the effect of different levels of internal pressure and different types of composite material on the failure limit for limiting capability of applying thatproduct in practical field.The results are compared with those obtained from the corresponding model where xy-strain of composite material reinforced with random fiber glass increases with rate (98%) while in the composite material reinforced with fiber glass arrangedwith 45o it increases with rate (99.8 %) due to increase in the internal pressure to (0.9-5) MPa. The comparison between theoretical and numerical results gives a good agreement.

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