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Article
Influence of Geogrid Reinforced Loose Sand In Transfer of Dynamic Loading To Underground Structure

Authors: Mohammed Y. Fattah --- Nahla M. Salim --- Mohammad S. Ismaiel
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 11 Part (A) Engineering Pages: 1915-1927
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Underground facilities are an integral part of the infrastructure of modern society and are used for a wide range of applications, including subways and railways, highways, material storage, and sewage and water transport. Underground facilities built in areas subject to dynamic activity must withstand both dynamic and static loading. This study focuses on the effect of the geogrid reinforcement in transfer of the dynamic load to the underground structure. The underground structure was simulated as a PVC pipe 110 mm in diameter inside the sandy soil. In order to investigate the response of soil, footing and underground tunnel to dynamic loading, a physical model was manufactured. The manufactured physical model could be used to simulate the application of dynamic loading. The total number of the tests carried out is 4 models. All the 4 model tests with relative density equal to 40% corresponding to loose sand. The applied harmonic load has an amplitude of 0.5 ton and a frequency of 2 Hz. For each amplitude and frequency of the load, the sand models were tested without geogrid and with geogrid of three series of geogrid depths from the model surface (0.5B, 1B and 1.5B) and width equal to (1B), where B is the strip footing width. The dynamic load was applied in the tests by a hydraulic jack system. The response of the tunnel to dynamic loading includes measuring the pressure above the crown of the tunnel by using a pressure cell (manufactured by Geokon company) as well as measuring the amplitude of displacement by using a vibration meter. The response of footing was elaborated by measuring the total settlement using sensors in the dynamic load apparatus. It was found the pressure above the crown of the tunnel decreased by about (14-33) % when using geogrid reinforcement. Also, it was found the settlement decreased by about (13-20) % when using geogrid reinforcement.

Keywords

Tunnel --- dynamic load --- geogrid --- load transfer


Article
DYNAMIC LOAD BALANCING IN AD HOC NETWORK USING OMNET++ SIMULATER

Author: Zainab saad Karam Almosawi
Journal: Misan Journal of Acodemic Studies مجلة ميسان للدراسات الاكاديمية ISSN: 1994697X Year: 2016 Volume: 15 Issue: 29 Pages: 132-153
Publisher: Misan University جامعة ميسان

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Abstract

ABSTACTload balancing problem remains a critical issue and has a high priority in ad hoc network especially after the growing demand for this network. Designing effective load balancing strategies for this network is known to be difficult because of the complexity of the structure of the network, due to the nature of the variety of the dynamic connection nodes in ad hoc network. This complexity in ad hoc network may be influenced on many factors like performance, energy efficiency, scalability, power consumption, network topology.This paper describes five proposed methods for solving load balancing problem by applying them on node, link or on both of the node and link at the same time. The proposed methods are designed for dynamic load balancing based on the fuzzy neural network characterization benefits.Each proposed method uses some metrics to find load balancing in ad hoc network like bandwidth of link (amount of data that the link accepted it at the time (capacity)), throughput of node (a moment of data that processing at the time), queue state of node (under full ….. over full) ….etc. Since some problems like routing can be depended on these metrics. Load balancing attempts to maximize network throughput by distributing the load between links (or nodes) of the network, for example the traffic may be moved from the overloaded nodes to other lightly loaded.


Article
SLIP DETECTION FOR A SPECIFIC DESIGN OF FINGERTIP IN MULTI-DIRECTION UNDER DIFFERENT LOAD CONDITIONS

Authors: Hayder Ahmed Abdulrazzaq --- Ihsan Abdulhussein Baqer --- Mauwafak Ali Tawfik
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 1 Pages: 103-116
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

In this paper, a novel design of robotic fingertip has been proposed to detect slippage between the robotic fingertip and the grasped object in multi-direction under different types of loads (static and dynamic loads). The detection process is based on the monitoring of variation in the normal to the tangential component of contact force ratios. The fingertip is composed of a compression springs and a conventional force sensors that are mounted to be able to measure the contact force components continuously. A mathematical model has been derived relative to a proposed design with the help of Matlab-Simulink program. Furthermore, the robotic hand mechanism contains the flexible parts to adapt the grasping force during the slippage occurrence period in spite of the hand actuator is in a stopped status. The grasped object is designed in a cube shape with two unbalance DC motors to generate an excitation that is used as an external dynamic load. The experimental results revealed that the proposed design for detecting slippage in multi-direction is feasible and effective for improving the stability of the grasping process.


Article
A Correlation Between Dynamic and Static Pile Load Test Results
مقارنة بين نتائج فحص الركائز الستاتيكي والديناميكي

Authors: Kais T. Shlash --- Hussein H. Hussein
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2009 Volume: 27 Issue: 15 Pages: 2730-2737
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Three selected bored piles executed at Basrah area were tested both bystatic and dynamic pile test procedures in order to correlate their results when evaluating the piles capacities. The correlation showed that the results are close to each other in terms of load- settlement relations, but on the other hand, end bearing capacity and skin friction values obtained by the dynamics tests are far from the real behavior of piles. The reason may be due to lack of experience ofcrew that supervises the dynamic tests. They have to practice more dynamic tests and should build accumulated knowledge about the dynamic method of testing piles. The time is still early for the dynamic tests to replace the classical static test when evaluating piles capacities.

تم فحص عدد من الركائز المختارة بطريقتي التحميل الستاتيكي التقليدية والطريقة الديناميكية في محاولة لربط نتائج الفحص بالطريقتين و دراسة امكانية الاعتماد على فحص الركائز بالطريقة الديناميكية دون اللجوء الى فحص التحميل الستاتيكي المعمول به حاليا. وجد من خلال المقارنة بين نتائج الفحص بالطريقتين ان هناك تقارب جيد بين الطريقتين من حيث شكل العلاقة بين الحمل و الهبوط و لكن قيم مقاومة الاحتكاك و مقاومة بهاية الركيزة التي تسجلها الطريقة الديناميكية تختلف كثيرا عن تلك المحسوبة على ضوء خواص التربة المنفذة خلالها الركائز. قد يكون السبب في ذلك هو عدم كفاءة الفاحصين في تنفيذ الفحص و خاصة موضوع ادخال بعض المتغيرات الواجب تغذيتها الى برنامج الفحص الديناميكي وعليه يحتاج الفاحصون بالطريقة الديناميكية الىممارسة وجهد اكبر لغرض الالمام قبل اعتماد الطريقة الديناميكية في تقرير تحمل الركائز. على ضوء النتائج التي تم الحصول عليها يمكن القول بان احلال الفحص الديناميكي بدل الفحص الستاتيكي التقليدي امر يحتاج الى مزيد من الخبرة و الدراسة قبل اعتماده في العراق


Article
Deterministic Analysis of Wind Loads Effects on High-Rise Buildings
التحليلات المحددة لتأثير أحمال الرياح على البنايات العالية متعددة الطوابق

Authors: Ashraf Hameed Alsalmani أشرف حميد السلماني --- Salah R. Al Zaidee صلاح رحيمة عبيد
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2015 Volume: 21 Issue: 4 Pages: 123-137
Publisher: Baghdad University جامعة بغداد

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Abstract

This paper studies the effect of mean wind velocity on tall building. Wind velocity, wind profile and wind pressure have been considered as a deterministic phenomenon. Wind velocity has been modelled as a half-sinusoidal wave. Three exposures have been studied B, C, and D. Wind pressure was evaluated by equation that joined wind pressure with mean wind velocity, air density, and drag coefficient. Variations of dynamic load factor for building tip displacement and building base shear were studied for different building heights, different mode shapes, different terrain exposures, and different aspect ratios of building plan. SAP software, has been used in modelling and dynamic analysis for all case studies.Results For different building heights considered maximum dynamic load factor (DLF) occurs in height range from 100-150m because fundamental building frequency is so close as to dominate wind frequency. Effects of higher modes become insignificant for height greater than 175m. Effect of three different terrain exposures B, C, and D on DLF for tips displacement and building base shear have been insignificant effect on response of tip displacement and building base shear. . Finally, effect of aspect ratio λ for different building heights with dynamic load factor (DLF) for tips displacement and for building base shear have λ approaching 2, fundamental building frequency is so closed to dominate wind frequency.

تمت دراسة تأثير الرياح في معدلاتها ، سرعة الرياح ، مقطع الرياح و ضغط الرياح والذي تم اعتباره كظاهرة محددة ، سرعة الرياح تمت معاملتها كدالة نصف جيببة. تم تصنيف الأرض الى ثلاث مناطق تعرض هي B و C و D. تم تقييم ضغط الرياح من خلال معادلة تربط ضغط الرياح بمعدل سرعة الرياح و كثافة الهواء و معامل الأعاقة.تمت دراسة تأثير الرياح في معدلاتها ، على اختلاف معامل الحمولة الديناميكية لأقصى ازاحة واكبرقوة قص في القاعدة اخذين بنظر الأعتبار المعاملات التالية: ارتفاع البناية ، خشونة تضاريس المنطقة، طور الأهتزاز، نسبة الطول الى العرض بالنسبة للبناية. كانت النتائج لعدة ارتفاعات للبناية لأقصى ازاحة واكبر قوة قص في القاعدة مع اختلاف معامل الحمولة الديناميكية تحدث في مدى ارتفاع البناية بين (100-150)م وذلك بسبب معامل الحمولة الديناميكية يزداد عند اقتراب تردد الرياح من أحد ترددات البناية.بالنسبة لنتائج تأثير طور الأهتزاز مع اختلاف معامل الحمولة الديناميكية لأقصى ازاحة واكبرقوة قص في القاعدة كان التأثير غير مهم عندما يكون ارتفاع البناية اكبرمن 175م.كانت نتائج تأثير مناطق التعرض الثلاث B و C و D مع اختلاف معامل الحمولة الديناميكية لأقصى ازاحة واكبرقوة قص في القاعدة تأثيرها غير مهم.اخيرا كان تأثير اختلاف نسبة الطول الى العرض بالنسبة للبناية مع اختلاف معامل الحمولة الديناميكية لأقصى ازاحة واكبرقوة قص في القاعدة عندما تكون λ مساوية الى 2 وذلك بسبب معامل الحمولة الديناميكية يزداد عند اقتراب تردد الرياح من أحد ترددات البناية.


Article
A Comparison Between Static and Dynamic Load Tests on Bored Piles

Author: Makki K .Al-Recaby
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2016 Volume: 34 Issue: 15 Part (A) Engineering Pages: 2993-3004
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Pilesr are both statically and dynami cally tried to acquire the limit and to check outline. The two sorts will give comes about that may differ in light of the technique utilized as a part of leading the test. It is thusly, important to think about the aftereffects of a static load test with dynamic load test. Numerous comparison studies are directed around the world, yet the vast majority of them are for displacement driven pile. In this way, the consequences of the test are looked at for substitution-exhausted piles. The piles are tested statically before dynamic test. The test results show that a not too bad comprehension was expert between both the tests with in addition to less 7mm at design load regarding settlement. Moderately, the settlement foreseen in powerful load test is littler diverged from static load test. Regarding absolute bearing limit, Davisson's technique gives the insignificant outrageous load regard diverged from various strategies. The Davisson's strategy is utilized to analyze the outcomes since it is more moderate. The examination shows that the piles are inside 15% in regard as far as possible traversed Davisson's strategy. Since the static test was coordinated before unique test, the limit got from dynamic test is higher because of the pile experienced flexible pressure amid static load test and furthermore because of soil setup.


Article
Dynamic Response of a Cracked Composite Beam subjected to moving Load

Author: Nazhad Ahmad Hussein
Journal: Anbar Journal of Engineering Sciences مجلة الأنبار للعلوم الهندسية ISSN: 19979428 Year: 2019 Volume: 7 Issue: 4 Pages: 393-398
Publisher: University of Anbar جامعة الانبار

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Abstract

The forced deflections of simply supported cracked composite beams are investigated when subjectedto moving dynamic load. The crack is modeled as rotational spring and used in the formulationof the composite beam with a moving load in sinusoid wave. The numerical solution issatisfactory compared to the experimental results. The effects of crack depth and crack positionsat different load speed are studied. The results show that the forced deflection increased withincreasing the speed ratio and crack depth.


Article
STUDY THE INFLUENCE OF SHOT PEENING TIME ON BUCKLING BEHAVIOR OF MEDIUM CARBON STEEL (CK 35) UNDER DYNAMIC LOADING (EXPERIMENTALLY AND NUMERICALLY)
دراسة تأثير السفع بالكريات على تصرف الانبعاج للفولاذ متوسط الكربون ((Ck35 تحت الاحمال الدينامية

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Abstract

A study of dynamic buckling behavior (experimentally and numerically) under increasing load had been conducted on medium carbon steel (CK35) specimen. 24 specimens were tested under compression loading, 12 specimens are long and others are intermediate. All these specimens were tested under four shot peening times (SPT) (0, 15, 25, 30) minutes. It was concluded that, the best buckling strength was appeared at (25 min) shot peening time. Also, the comparison between the experimental and numerical results showed good agreement between these results with maximum difference was about (12%).

دراسة سلوك الانبعاج الديناميكي (عمليا وعدديا) عند زيادة الحمل أجرت على عينات فولاذ متوسط الكاربون (CK35). 24 عينه اختبرت تحت تأثير حمل انضغاطي, 12 عينه طويلة والباقي متوسطه الطول. كل هذه العينات اختبرت عند أربعه أزمان للسفع بالكريات هي (0, 15, 25, 30) دقيقه. تم استنتاج مايلي, أفضل سلوك للانبعاج ظهرت عند (25 دقيقه) زمن سفع بالكريات. كذلك, المقارنة بين النتائج العملية والعددية أظهرت توافق جيد بين هذه النتائج بأكبر فرق لايتجاوز (12) %.


Article
Reduction of Noise and Vibration of Spur Gear by Using Asymmetric Teeth Profiles with Tip Relief
اختزال الضوضاء والاهتزاز للمسننات العدلة بواسطة جانبيات الاسنان غير المتناضرة مع تشذيب الحواف

Authors: Mohammad Qasim Abdullah محمد قاسم عبد الله --- Adnan Naji Jameel عدنان ناجي جميل --- Husam Saad Hasan حسام سعد حسن
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2015 Volume: 21 Issue: 9 Pages: 105-118
Publisher: Baghdad University جامعة بغداد

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Abstract

Reduction of noise and vibration in spur gear experimentally by using asymmetric teeth profiles with tip relief was presented. Both of classical (symmetric) and asymmetric (with and without tip relief) spur gears are used in this work. Gear test rig was constructed to achieve torsional vibration measuring, and two modified cutters are designed and manufactured to achieve tooth profile modifications. First to cut asymmetric gear tooth with pressure angles (14.5o/25 o) without tip relief for loaded and unloaded tooth sides respectively, and second to cut asymmetric gear tooth with pressure angles (14.5o/25 o) for loaded and unloaded tooth sides respectively with tip relief to achieve best dynamic performance. Dynamic load factor, transmission error and noise level are carried out in this work. Final results showed improvement in dynamic load factor and noise level for asymmetric gear (with and without tip relief) compared with classical spur gear.

تم تقديم اختزال الضوضاء والاهتزاز للمسننات العدلة عمليا بواسطة استخدام جانبيات اسنان غير متناضرة مع تشذيب الحواف في هذا البحث. كلا من الاسنان المتناضرة والغير متناضرة ( مع تشذيب الحواف وبدونها) تم استخدامه في هذا العمل. منصة اختبار المسننات بنيت خصيصا لتحقيق قياس الاهتزاز الدوراني وتم تصميم وتصنيع قاطعات مسننات محورة لتحوير جانبيات الاسنان. الاولى لقطع مسنن غير متناظر ذو زوايا ضغط (14.5/25 ) درجة بدون تشذيب الحواف. والثانية لقطع مسنن غير متناضر ذو زوايا ضغط (14.5/25 ) درجة ذو خاصية على تشذيب حواف المسنن وذلك لضمان افضل اداء ديناميكي . في هذا البحث تم استخراج معمل الحمل الديناميكي وخطا النقل الديناميكي ومستوى الضوضاء . النتائج النهائية اظهرت تحسين في معمل الحمل الديناميكي ومستوى الضوضاء للمسننات غير المتناضرة ( بوجود وعدم وجود تشذيب لحافات الاسنان ) مقارنة بالاسنان التقليدية .


Article
A Load Balancing Scheme for a Server Cluster Using History Results
توزيع مهام مجموعة خوادم بأستخدام النتائج القديمة

Author: Husam Ali Abdulmohsin
Journal: Iraqi Journal of Science المجلة العراقية للعلوم ISSN: 00672904/23121637 Year: 2016 Volume: 57 Issue: 3B Pages: 2121-2130
Publisher: Baghdad University جامعة بغداد

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Abstract

Load balancing in computer networks is one of the most subjects that has got researcher's attention in the last decade. Load balancing will lead to reduce processing time and memory usage that are the most two concerns of the network companies in now days, and they are the most two factors that determine if the approach is worthy applicable or not. There are two kinds of load balancing, distributing jobs among other servers before processing starts and stays at that server to the end of the process is called static load balancing, and moving jobs during processing is called dynamic load balancing. In this research, two algorithms are designed and implemented, the History Usage (HU) algorithm that statically balances the load of a Loaded Web Server (LWS) and the Massage Passing Optimization (MPO) algorithm. HU algorithm is used at the Domain Name System (DNS) side is to minimize the time required to execute the client requests based on using history results available in one of the Web servers in the server cluster. The MPO is for optimizing the message passing between the Web servers and the DNS. This message optimization will lead to optimize the processing time in the DNS cluster required to find under-loaded Web servers that will perform the request.

موازنة الحمل من المواضيع التي جذبت انتباه اكثر الباحثين في العقد الاخير من الزمن. موازنة الحمل تؤدي الى عاملين, تقليل وقت معالجة البيانات و تقليل استخدام الذاكرة لذلك تعتمد الشركات على هذين العاملين في تقييم اي نظرية تخص موازنة الحمل. هنالك نوعان من نظريات موازنة الحمل, النوع الثابت, هذا النوع يقوم بتوزيع المهام من جهة الخادم المحمل بالمهام الى الخوادم الغير محملة بالمهام قبل بدء المهام, و هنالك النوع المتحرك, و هنا من الممكن ان يتم توزيع المهام حتى اثناء تنفيذها. استخدام مصادر و امكانيات خوادم غير مشغولة او غير مستخدمة سوف تكسب المنظومة وقت و تلغي الحاجة الى اي تتطوير في المنظومة و التي تكلف الكثير. في هذا البحث تم تصميم خوارزميتين, خوارزمية استخدام التأريخ (HU) و خوارزمية تقليل مناقلة الرسائل (MPO). يتم استخدام نظرية ال HU عند جهة نظام مجال الاسم (DNS) و الذي يقوم بتوجيه المهام المرسلة من قبل الزبون الى اي خادم ضمن المدى و الذي قام بتنفيذ نفس المهام في الماضي و يتم استخدام خوارزمية ال MPO لغرض تقليل مناقلة الرسائل بين الخوادم و ال DNS و بالتالي تقوم الخوارزمية بتقليل وقت التنفيذ في ال DNS من خلال تقليل وقت ايجاد خوادم في حالة ركود او غير محملة و التي سوف تقوم بتنفيذ المهام.

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