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Effect the Grain Size on the Polymer Matrix Composites Reinforced by Reenia Particles
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 Synthetic polymers such as polyurethane are used widely in the field of biomedical applications such as implants or part of implant systems.

This paper focuses on the preparation of base polymer matrix composite materials by (Hand Lay-Up) method, and studying the effect of selected grain size (32, 53, 63, 75, and 90) µm of (Reenia) particles on some properties of the prepared composite.

Mechanical tests were used to evaluate the prepared system (Tensile, Compression, Impact, and Hardness) tests, and a physical test of (Water absorption %), and all tests were accomplished at room temperature.

Where results showed tensile test (maximum tensile strength and modulus of elasticity) high at small grain size while the percentage of elongation decreased with increasing size. As the compressive strength increased with small grain size. And also the values of hardness and fracture energy affected by particle size where the hardness and fracture energy increased at small particles size of compared to larger particles size. While the percentage of water absorption increased at large particle size.

In general the results showed clear improvement in properties and maximum values which get it of tensile strength, Modulus of elasticity, elongation percentage, compression strength, fracture energy, hardness and water absorption were as follows ((34.8 MPa), (10%), (268 N/mm2), ( 54.2 MPa),( o.408 J), (78.9 Shor (D)), (0.2668 %)) at using  (32µm)) except water absorption was at  (90µm) .

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Publication Date
Tue Dec 31 2013
Journal Name
مجلة كليه التربيه الاساسيه
صعوبات تدريس مادة الكيمياء الكمية في قسم الكيمياء - كلية التربية - للعلوم الصرفة من وجهة نظر تدريسي المادة و الطلبة
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تعد أساليب وطرائق تدريس المواد الدراسية العلمية من المجالات المهمة التي تساعد في تحويل المجرد إلى ثوابت في الذهن وترفع مستوى خبرات كل من المعلم والمتعلم على حد سواء إضافة إلى إنها جزء لا يتجزأ من العملية التربوية ومن الركائز المهمة التي تقوم عليها المناهج الدراسية لأنها تساعد الطلبة على اكتساب مهارات ومعلومات وتكوين اتجاهات وميول تخدم أهداف تدريس المادة وبما أن مادة الكيمياء الكمية هي إحدى المواد الدراسية

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Publication Date
Wed Sep 25 2019
Journal Name
Journal Of The College Of Education For Women
أثر انموذج بوسنر في تحصيل مادة الرياضيات لدى طلاب الصف الثاني المتوسط
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     يهدف البحث الحالي الى معرفة أثر انموذج بوسنرفي تحصيل مادة الرياضيات لدى طلاب الصف الثاني المتوسط .

ولتحقيق هدف البحث صاغت الباحثة الفرضية الآتية :

      لا يوجد فرق ذو دلالة إحصائية عند مستوى (0,05) بين متوسط درجات طلاب المجموعة التجريبية الذين درسوا مادة الرياضيات  وفق انموذج بوسنر، وبين متوسط درجات طلاب المجموعة الضابطة الذين درسوا المادة نفسها بالطريقة الاعتيادية في اخت

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Publication Date
Fri Jun 30 2023
Journal Name
مجلة نسق
اثر استراتيجية القوائم المركزة في تحصيل مادة الكيمياء طلاب الصف الثاني المتوسط
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يهدف البحث التعرف على اثر استراتيجية القوائم المركزة في تحصيل مادة الكيمياء عند طلاب الصف الثاني المتوسط وتم استخدام المنهد التجريبي ذو الضبط الجزئي وكذلك تم اختيار مجامع البحث جميع طلاب المدارس الثانوية والمتوسطة التابعة لمديرية تربية كربلاء

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Publication Date
Mon Jan 01 2007
Journal Name
Journal Of Educational And Psychological Researches
أثر أنموذج لاندا في تحصيل طالبات الصف الخامس العلمي في مادة الاحياء
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اظهرت نتائج ابحاث تربوية اجريت في الولايات المتحدة الامريكية ان تدريس مادة الاحياء يعتمد على حفظ المصطلحات والمفاهيم العلمية دون فهم واستيعاب لها، كما ان الاساليب والطرائق التدريسية المتبعة تقليدية وتؤكد على الجوانب الشكلية والنظرية والحفظ والتلقين. (عايش،1999،ص8).

        واشارت دراسة في وزارة التربية العراقية ان مادة الاحياء تشارك بعض المواد الاخرى في صعوبتها في المرحلة

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Publication Date
Sat Sep 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
The effect of strategic decisions for operations management in performance excellence organizational.
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This research focused on clarifying the relationship strategic decisions for operations management & performance excellence organizational, The research emerges from a problem which explained by many application questions. Special questionnaire has been prepared for this purpose distributed (72) to sample of  management levels (Top, middle) in the General company for mining industries and aquatic Insullation & the General company of batteries industry, The research has tried to test a number hypotheses related to the relation and regression among the variables of the research, and the differences among the <

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Engineering
The Response of Reinforced Concrete Composite Beams Reinforced with Pultruded GFRP to Repeated Loads
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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Engineering
The Response of Reinforced Concrete Composite Beams Reinforced with Pultruded GFRP to Repeated Loads
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This paper investigates the experimental response of composite reinforced concrete with GFRP and steel I-sections under limited cycles of repeated load. The practical work included testing four beams. A reference beam, two composite beams with pultruded GFRP I-sections, and a composite beam with a steel I-beam were subjected to repeated loading. The repeated loading test started by loading gradually up to a maximum of 75% of the ultimate static failure load for five loading and unloading cycles. After that, the specimens were reloaded gradually until failure. All test specimens were tested under a three-point load. Experimental results showed that the ductility index increased for the composite beams relative to the refe

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Publication Date
Sun Jan 01 2023
Journal Name
Journal Of Engineering
The Response of Reinforced Concrete Composite Beams Reinforced with Pultruded GFRP to Repeated Loads
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This paper investigates the experimental response of composite reinforced concrete with GFRP and steel I-sections under limited cycles of repeated load. The practical work included testing four beams. A reference beam, two composite beams with pultruded GFRP I-sections, and a composite beam with a steel I-beam were subjected to repeated loading. The repeated loading test started by loading gradually up to a maximum of 75% of the ultimate static failure load for five loading and unloading cycles. After that, the specimens were reloaded gradually until failure. All test specimens were tested under a three-point load. Experimental results showed that the ductility index increased for the composite beams relative to the reference specim

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Publication Date
Mon Oct 01 2012
Journal Name
Iraqi Journal Of Physics
Synthesis and study the electrical properties of carbon nanotubes- polyvinylchloride composites
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The aim of this paper, study the effect of carbon nanotubes on the electrical properties of polyvinylchloride. Samples of polyvinylchloride carbon nanotubes composite prepared by using hot press technique. The weight percentages of carbon nanotubes are 0,5,10 and 20wt.%. Results showed that the D.C electrical conductivity increases with increasing of the weight percentages of carbon nanotubes. Also, the D.C electrical conductivity changed with increase temperature for different concentrations of carbon nanotubes. The activation energy of D.C electrical conductivity is decreased with increasing of carbon nanotubes concentration.

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Publication Date
Mon Sep 01 2014
Journal Name
Al-khwarizmi Engineering Journal
An Experimental Study of the Effect of Vortex Shedding on Solar Collector Performance
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In this work, the effect of vortex shedding on the solar collector performance of the parabolic trough solar collector (PTSC) was estimated experimentally. The effect of structure oscillations due to wind vortex shedding on solar collector performance degradation was estimated. The performance of PTSC is evaluated by using the useful heat gain and the thermal instantaneous efficiency. Experimental work to simulate the vortex shedding excitation was done. The useful heat gain and the thermal efficiency of the parabolic trough collector were calculated from experimental measurements with and without vortex loading. The prototype of the collector was fabricated for this purpose. The effect of vortex shedding at different operation condition

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