research centers


Search results: Found 20

Listing 1 - 10 of 20 << page
of 2
>>
Sort by

Article
Embedded Length Of Steel Bars In Self Compacted Concrete (SCC)

Authors: Ali I. Salahaldin --- Amer F. Izzat
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2011 Volume: 17 Issue: 5 Pages: 1077-1089
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Experimental research was carried out on eight reinforced concrete beams to study the embedded length of the longitudinal reinforcement. Six beams were casted using self compacted concrete, and the two other beams were casted using normal concrete. The test was carried out on beams subjected to two point loads. The strain and the slip of the main reinforcement have been measured by using grooves placed during casting the beams at certain places. The measured strain used to calculate the longitudinal stresses (bond stress) surrounding the bar reinforcement, The study was investigated the using of self compacted concrete SCC on the embedded length of reinforcing bars, and comparing the results with normal concrete.The test results show that using SCC improve the concrete properties like the compressive strength and the tensile strength which mainly affected the bond strength and the splitting of the concrete cover failure. The testes show that with increasing concrete strength the bond strength increased.

دراسة عملية اجريت على ثمان عتبات خرسانية مسلحة لدراسة طول الطمر لقضبان حديد التسليح الموضوع في الخرسانة.ست نماذج استخدمت فيها الخرسانة ذاتية الرص ونموذجان استخدم فيهما خرسانة اعتيادية. الفحوصات اجريت على عتبات حملت بنقطتي تحميل. وباستخدام فراغات معينة وضعت في اثناء الصب داخل النماذج لقياس الانفعالات في قضبان حديد التسليح وكذلك لقياس الانزلاق الذي من الممكن ان يحدث, تم قياس اجهاد القص المحيط بقضبان حديد التسليح والمسبب للفشل وانسحاب قضبان حديد التسليح. الدراسة ركزت على عاملين رئيسيين هما:-قوة تحمل الخرسانة.-وطول الطمر المتاح لقضبان حديد التسليح.لايجاد كيفية تاثيرهما على قيم اطوال الطمر في حالة استخدام خرسانة ذاتية الرص. وكذلك مقارنة النتائج مع الخرسانة الاعتيادية. اظهرت النتائج تحسن في خواص الخرسانة في حالة استخدام الخرسانة ذاتية الرص من ناحية مقاومة الانضغاط ومقاومة الشد الذي يؤثر تاثير مباشر على مقاومة الترابط وفشل الغطاء الخرساني وتهشمه


Article
The Effective Embedded Length of Steel Bars in Self Compacted Concrete (SCC)

Authors: Ali I. Salahaldin --- Amer F. Izzat
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2011 Volume: 17 Issue: 3 Pages: 594-609
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Eight reinforced concrete beams were tested in order to investigate the effective embedded length of the longitudinal reinforcement bar in self compacted concrete (SCC). All specimens were reinforced with a uni-reinforced bar, six of them embedded in self compacted concrete and the others embedded in normal concrete. The test was carried out on simply supported beams loaded at two points. At the end of the reinforcement bar slip was measured, also under the loading point slip and the bar strain were measured. The investigated variables in this study were: The bar diameter, and the available embedded length.To find out how these variables influence the embedded length in case of using self compacted concrete and comparing it with the normal concrete. The results show that, with increasing the bar diameter, bond stress slightly decreases, while with increasing the embedded length of the longitudinal bar the bond stress decreases and this improves the mode of the bond failure, especially for the specimens having small bar diameter

دراسة عملية اجريت على ثمان عتبات خرسانية مسلحة لدراسة الطول المطمور لقضبان حديد التسليح الموضوع في الخرسانة ذاتية الرص . كل التماذج تحتوي على قضيب تسليح احادي . ست منها استعملت فيها خرسانة ذاتية الرص ونموذجين استعمل فيها الخرسانة الاعتيادية. الفحوصات اجريت على عتبات بسيطة الاسناد, حملت بنقطتي تحميل. في نهاية حديد التسليح تم قياس الانسحاب , واسفل نقطة التحميل تم قياس الانسحاب لحديد التسليح مع الانفعال الحاصل في حديد التسليح.تم بحث المتغيرات التالية في هذه الدراسة: قطر قضيب حديد التسليح. وطول التثبيت المتاح لقضبان التسليح.لايجاد كيفية تاثيرهما على قيم الطول المطمور في حالة استخدام خرسانة ذاتية الرص ومقارنتها بالخرسانة الاعتيادية.اظهرت النتائج المختبرية بانه مع ازدياد قطر حديد التسليح يقل اجهاد الترابط بمقدار طفيف. ومع ازدياد الطول المطمور يقل اجهاد الترابط وهذا يحسن من نوع فشل الترابط الحاصل, وخصوصا في النماذج الحاوية على تسليح قليل.


Article
Arm Span to Height Ratio in Relation to Severity of Dyspnea
العلاقة بين مدى اتساع الذراعين الى الطول مع شدة عسر التنفس

Author: Amar K. Muhamad عمار قاسم محمد
Journal: Journal of the Faculty of Medicine مجلة كلية الطب ISSN: PISSN: 00419419 / EISSN: 24108057 Year: 2012 Volume: 54 Issue: 2 Pages: 131-133
Publisher: Baghdad University جامعة بغداد

Loading...
Loading...
Abstract

Background: Arm span is the closest physiologic measurement to standing height. Increased arm span to standing height ratio, which indicates a possible loss of height, due to aging, often results from osteoporosis-related vertebral collapse or other causes. This has possible consequences on lung functions. Objective: To evaluate the effects of aging related loss of height to severity of dyspnea.Method:Patients visited pulmonary function test laboratoryat Baghdad teaching hospital outpatient clinic department from first of November 2009 to thirty first of December 2010 for preoperative assessment were recruited to participate in our study. All recruited subjects were evaluated with a clinical history and physical examination followed by measurements of arm span, standing height, weight, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC). Patients 40 years old of age and older were included .Patients with chronic disabilities (cardiac, respiratory or systemic diseases) were excluded. Patients were classified according to their gender and Medical Research Council severity of dyspnea.Results: one hundred thirty one subjects aged 40 years and older were recruited for this study. Arm span to height ratio was significantly negatively correlated with FEV1/FVC ratio, FVC, and posi-tively correlated with severity of dyspnea. Conclusion:There is a significant association between increased arm span to height ratio with in-creased severity of dyspnea. The role of arm span measurements in assessment of pulmonary func-tion tests in older patients and the association between loss of height and dyspnea deserves further evaluation. Keywords:Arm Span,height ratio, dyspnea.

الخلفية :امتداد الذراعين هو اقرب قياس فسلجي للطول.زيادة نسبة الطول الى امتدادالذراعين,التي قد تعني احتمال نقص الطول نتيجة للتقدم في السن ,والذي قد ينتج عن وهن العضام المؤدي الى تهشم الفقرات,او اسباب اخرى.مما قد يكون له علاقة بوضائف الرئة.الطرائق: المشاركين الذين راجعوا مختبر فحص وضائف الرئة في العيادة الاستشارية لمستشفى بغداد التعليمي للفترة من1/11/2009ولغاية31/12/2011,لاسباب متعددة,تم ادخالهم في هذه الدراسة.كل المشاركين تم اخذ التاريخ الطبي وفحصهم سريريا وقياس طولهم,مع قياس امتداد الذراعين . .FEV1, و FVC, وزنهم,فقط المشاركين 40 سنة فاكثر تم شمولهم. المشاركين الذين يعانون من اعاقات مزمنة (سواء كانت قلبية ,تنفسية اوعامة) تم استثناؤهم من هذه الدراسة.تم تقسيم المشاركين حسب الجنس وحسب تقييم مجلس البحوث الطبية لشدة عسر التنفس. النتائج:مئة وواحد وثلاثون مشاركا في هذه الدراسة,اعمارهم تتراوح من40 سنة فاكثر. نسبة الطول الى امتدادالذراعين ارتبطت بشكل سلبي احصائيا مع قياس السعة الحيوية القسرية قياس حجم الزفير القسري في الثانية الاولى /قياس السعة الحيوية القسري وارتبطت بشكل ايجابي احصائيا مع شدة عسر التنفس. الاستنتاجات:هذه الدراسة توصلت الى وجود ارتباط احصائي وثيق بين. نسبة الطول الى امتدادالذراعين معشدة عسر التنفس, ان دور قياس امتدد الذراعين واهميته في تقييم نتائج فحص وضائف الرئة عند كبار السن والعلاقة بين عسر التنفس مع خسارة الطول تحتاج الى مزيد من التقييم. مفتاح الكلمات: اتساع الذراعين ,الطول ,عسر التنفس


Article
Preparation and In-vitro Evaluation of Metoprolol Tartrate Proniosomal Gel
تحضير وتقييم مختبري لهلام البرونايوسوم للميتوبرولول تارتريت

Loading...
Loading...
Abstract

The aim of this research is to prepare metoprolol tartrate niosomal gel as transdermal drug delivery system and also to evaluate procedure related variables like type of surfactant and release of drug from niosomes. Metoprolol tartrate niosomes are formulated by coacervation-phase separation method using different types of non-ionic surfactant (Span or Tween of different HLB value), lecithin and cholesterol. The prepared formulations are estimated for its entrapment efficiency, vesicle size (optical microscope and ABT-9000 NANO Laser particle size analyzer), the compatibility of the drug and additives used (Fourier Transform Infra Red -FT-IR spectroscopy) and morphological characters (Scanning Electron Microscopy- SEM). Fourier Transform Infra Red (FT-IR) studies, confirm that there is no interaction between drug and other formulation components of niosome. Higher entrapment efficiencies are obtained with Span 40 and span 60 (86.6%±8.07 and 78.09±15.44 respectively) and the release rate at 11 hr from span 40 niosomes is found to be 31.18%. In conclusion, the niosomal gel formulation could be a promising transdermal delivery system for metoprolol tartarate with prolonged drug release profiles

الهدف من هذا البحث هو تحضير هلام النايوسوم لعقار الميتوبرولول تارتريت كنظام اعطاء للدواء عبر الادمة وكذلك تقييم المتغيرات المتعلقة بالطريقة كنوع العامل الفاعل وتحرر الدواء من النايوسوم.متوبرولول طارطريت حضرت بطريقة التقوصر باستخدام انواع مختلفة من العامل السطحي الفاعل الغير ايوني ( سبان او توين لقيم مختلفة من HLB) , الليسثين والكولسترول. إن الصيغ المحضرة قد قيمت لكفاءة التحميل ,حجم الحويصلة (المجهر الضوئي واليزري), توافق الدواء مع المواد الاضافية المستخدمه (مطياف الاشعة تحت الحمراء) والصفات التشكيلية (الماسح الاكتروني الدقيق). دراسات مطياف الاشعة تحت الحمراء اثبتت بأنه لا يوجد تفاعل بين العقار وبقية مكونات صيغة النايوسوم . كفاءات تحميل عالية تم تحصيلها مع سبان 40 و سبان 60 (86.6%±8.07 و78.09±15.44 بالتوالي) وسرعة التحرر عند الساعة 11 من سبان نايوسوم كانت 31.18%. بالنتيجة صيغة الهلام للنايوسوم قد تكون نظام واعد للاعطاء عبر الادمة لعقار الميتوبرولول تارتريت مع إطالة صور تحرر الدواء.


Article
Effect of Shear Span-Depth Ratio on Shear Strength of Porcelanite Lightweight Aggregate Reinforced Concrete Deep Beams Strengthened by Externally Bonded CFRP Strips

Authors: K.F. Sarsam --- N.A.M. Al-Bayati --- A.S. Mohammed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2017 Volume: 35 Issue: 3 Part (A) Engineering Pages: 267-275
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

This paper presents an experimental investigation of structural behaviour of reinforced concrete deep beams strengthened in shear by CFRP strips. The experimental program consisted of fabricating, casting and testing of nine identical porcelainte lightweight aggregate reinforced concrete deep beams. Three of the tested deep beams were unstrenghtened to serve as reference beams, while the remaining beams were tested after being strengthened using CFRP strips in two different orientations (vertical and horizontal). The locally available natural porcelanite aggregate is used to produce lightweight aggregate concrete. The beams were designed to satisfy the requirements of ACI 318M- 14 building code. In order to insure shear failure modes, adequate flexural steel reinforcement were provided. Effect of three different values of shear span to effective depth ratio (a/d =1.0, 0.8, 1.2) were selected. All beams have been tested as a simply supported beams subjected to two concentrated points loading. The beam specimens were tested up to failure under monotonic loads. The experimental work showed that the failure load increases as the shear span to effective depth ratio deceases. As the shear span to effective depth ratio decreased from 1.0 to 0.8, the percentage of increase in the ultimate load was about 24%. In addition, the diagonal compression strut crack of unstrenghtened control beams was changed to several diagonal cracks at mid depth within the shear span of the strengthened beams and exhibited more ductile failure mode.


Article
EFFECT OF WEB OPENING'S SHAPE ON THE BEHAVIOR OF HYBRID REINFORCED CONCRETE DEEP BEAMS UNDER REPEATED LOADING

Authors: Sawsan Akram Hassan --- Mohammed Kamil Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 3 Pages: 128-141
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

This research aims to study experimentally behavior of hybrid deep beams with web openings when subjected to two points' monotonic and repeated loading in effect of web openings shape. All tested deep beams have the same flexural (0.0184) and web reinforcement (ρw=0.003) and same dimensions of (1500mm length, 150mm width and 350mm height). In this research, the idea of hybridity was achieved by reinforcing the two shear spans with steel fiber keeping the middle span free from this fiber. The aim was to strengthen shear region against shear failure (diagonal strut failure). To achieve the aim, six deep beams were cast and tested. Three of them were tested under monotonic loading as control beams to the other three beams tested under repeated loading at levels of 55% of the ultimate load of their control beams. The variables studied were: loading type (either monotonic or repeated) and web opening shapes. The results indicated that using different opening shapes (rectangular, circular or square) with an equivalent shape of 1.37% of beam size show that the ultimate load of beams with rectangular opening decreases by 10% as compared with beams with square web openings of the same area. Also, the ultimate load of beams with circular openings increases by 6.8% as compared with beams with square web openings of the same area. Also, it can be concluded that deep beams haves circular openings are increasing in ultimate loads by 17.5% as compared to rectangular web openings shapes with equivalent area.


Article
BEHAVIOR OF HYBRID REINFORCED CONCRETE DEEP BEAMS WITH WEB OPENINGS UNDER REPEATED LOADING

Authors: Sawsan Akram Hassan --- Mohammed Kamil Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 4 Pages: 52-75
Publisher: Al-Mustansyriah University الجامعة المستنصرية

Loading...
Loading...
Abstract

This research aims to study experimentally behavior of hybrid deep beams when subjected to two point's monotonic and repeated loading in presence or absence of web openings. All tested deep beams have the same reinforcement in flexural (ρ= 0.0184) and web (ρw=0.003) and same dimensions of (1500mm length, 150mm width and 350 mm height). In this research, the idea of hybridity was achieved by reinforcing the two shear spans with steel fiber keeping the middle span free from this fiber. The aim was to strengthen shear wings against shear failure (diagonal strut failure). To achieve the aim, twelve deep beams were cast and tested. Six of them were tested under monotonic loading as control beams to the other six beams tested under repeated loading at levels of 55% of the ultimate load of their control beams. The variables attempts were: loading type (either monotonic or repeated), beam type (either hybrid or non-hybrid), steel fiber (SF) ratio, and finally web opening sizes. The results illustrate that the ultimate load of deep beam with web openings under monotonic loading increases as the SF ratio increases. When SF was added to shear spans with a ratios of 1% and 2% under monotonic loading system, the ultimate load percentages increase are 37.5% and 68.75%, respectively compared with ultimate loads of beams which are without SF. Also, using fiberous concrete in casting the entire length of beams leads to an increase in the ultimate load of 4.55% as compared with deeps beams with the same SF ratio of 1%, and 43.75% as compared with beams cast with conventional concrete. The results using different opening size of square shapes, it was found that the ultimate load decrease as size of web openings increases from 0.61% of beam size to 1.37% of beam size by 10.17% and 25.42%, respectively as compared with hybrid deep beam without openings.


Article
Effect of CFRP Strips Orientation on Performance of Strengthened Deep Beams

Author: Ahmed Sagban Saadoon
Journal: Al-Qadisiyah Journal for Engineering Sciences مجلة القادسية للعلوم الهندسية ISSN: 19984456 Year: 2019 Volume: 12 Issue: 3 Pages: 172-177
Publisher: Al-Qadisiyah University جامعة القادسية

Loading...
Loading...
Abstract

This study was carried out in order to explore the behaviour of RC deep beams strengthening with CFRP strips. Eight simply supported deep beams were fabricated and tested under four-points loading scenario. Three different orientations for CFRP strips were used for strengthening the RC deep beams ; vertical, horizontal and inclined. All of the tested samples were of the same dimensions, concrete strength and steel reinforcement. A percentage increase in load carrying capacity of 48, 19 and 38% (with respect to the unstrengthened beam) was gained for beams strengthened with vertical, horizontal and inclined FRP strips, respectively. It was concluded that the strengthening with FRP strips of vertical fabric orientation is more efficient than strengthening with horizontal or inclined orientation since the vertical orientation gives the highest load carrying capacity, largest deflections at ultimate load and smallest crack width. On the other hand, applied the FRP strips in a horizontal orientation was insufficient for the strengthening purposes.


Article
Developing Multistage Heuristic Algorithm To Minimize Idle Time And Makespan In Job Shop Scheduling
بناء خوارزمية توجيهية متعددة المراحل لتدنية الوقت العاطل ووقت الأنهاء الأكبر في جدولة الأنتاج الوظيفي

Author: Mahmoud Abbas Mahmoud
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2010 Volume: 28 Issue: 14 Pages: 4789-4805
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

The behavior and performance of job shops have been the focus andattention in both operations research and operations management literature. Job shop scheduling has received this large amount of attention, because it has the potential to dramatically decrease costs and increase throughput, thereby, profits. Moreover, the increasing of product customization creates more job shop environment in manufacturing world. No doubt, a wide variety of approaches tothe modeling and solution of job shop scheduling problems have been reported in the literature. But, the research in this area is continuous. In this paper, Multistage Heuristic Algorithm based on priority dispatching rules is developed. This algorithm has been implemented to solve three cases. Schedules generated havebeen compared with those obtained by means of the basic algorithm. As a result, Multistage Heuristic Algorithm shows the ability of minimizing: machines idle time, total time of machines and makespan.

لقد لقى موضوع طبيعة وأداء نظم الانتاج الوظيفي اهتماما ملحوظا في أدبياتموضوعي بحوث العمليات وادارة العمليات على السواء. و يعودالسبب في هذا الحجم الواسع من الاهتمام بجدولة العمليات في نظم الانتاج الوظيفي لما لهذا الموضوع من أثر كبير في خفض الكلفة وزيادة الأنجاز وبالتالي زيادة الربح. اضافة لما ورد فان الازدياد بالتوجه نحو الانتاج التخصصي قد ادى الى توسع مساحة بيئة الانتاج الوظيفي في عالم التصنيع. لاشك بأنه يوجد في الأدبيات تنوعا واسعا في اساليب النمذجة والحل لمشكلة الجدولة هذه ولكن البحث في هذاالمجال مازال مستمرا. في هذه الورقة تم بناء خوارزمية توجيهية متعددة المراحل مبنية على قواعد الاسبقيات في التقديم. هذه الخوارزمية قد طبقت في حل ثلاث حالات وتم مقارنة الجدولة الناتجة لكل حالة مع تلك الناتجة من تطبيق الخوارزمية الاساسية. وقد اوضحت النتائج بان الخوارزمية الجديدة ادت الى تقليل الوقت العاطل والوقت الكلي للمكائن وكذلك وقت الأنهاء الأكبر.


Article
Anticipation ofMid-Span Deflection atUltimate Loadfor Concrete BeamsStrengthenedby FRP BarsUsing Artificial Neural Networks

Author: Abdulnasser Mohammed Abbas
Journal: Journal of University of Babylon مجلة جامعة بابل ISSN: 19920652 23128135 Year: 2018 Volume: 26 Issue: 5 Pages: 9-19
Publisher: Babylon University جامعة بابل

Loading...
Loading...
Abstract

A mid-span deflection of concrete beam strengthened by FRP bars has beenanticipated. A case of simply supported beam loaded by two point loads has been simulated by using artificial neural networks (ANNs) which are involved in MATLAB package, version 9.0.0.341360 (R2016a). The proposed model presupposes60 beam specimens to collect the required data for the neuralpattern. A set of 8 input variables was selected to construct the proposed neural pattern; these are, beam dimensions, concrete specifications, and FRP properties. While the mid-span deflection at the ultimate load, will be the output inconstant. The use of 9 nodes in the hidden layer is active in predicting the mid-span deflection. A comparison between the gained results and the past experimental data shows that the proposed neural patterngives a reasonable anticipation with an overall error of 8.2 %.

تمتخمينالهطول عند الحمل الاقصى لمنتصفعتبة خرسانية مسلحة بقضبان تسليح بوليمرية.تمتدراسةحالةعتبة بسيطة الاسناد معرضة الى حملين متناظرين باستخدامالشبكاتالعصبيةالاصطناعية الموجودة ضمن برنامج الماتلاب ذي الاصدار9.0.0.341360 (R2016a). لقد تم استخدام 60عينةلغرض جمعالبياناتالمطلوبةلمحاكاة النموذج. كما تماختيارمجموعة المدخلاتمن8متغيرات. تمثلت بأبعادالعتب،خصائصالخرسانة،وخصائصقضبانالتسليح البولمرية.في حين كانت بياناتالإخراج هي الهطول في منتصفالعتب عند الحملالاقصى. لقد وجد ان استخدام9عقدفيالطبقةالمخفيةفعالا لتوقع الهطول في منتصفالعتبة. لقد بينت المقارنةبينالنتائجالمكتسبةمعالبياناتالتجريبيةالسابقةأنالنموذجالمقترحأعطىتقييمامعقولاومعدل خطأ عاميساوي 8.2٪.

Listing 1 - 10 of 20 << page
of 2
>>
Sort by
Narrow your search

Resource type

article (20)


Language

English (20)


Year
From To Submit

2019 (6)

2018 (3)

2017 (2)

2016 (1)

2015 (1)

More...