Abstract Laser surface treatment of materials is one of the most effective methods of improving properties and performance of metallic articles. This technique proved its capabilities and advantages in comparison with other methods of surface treatment As an example, it has been shown that the distortion caused by this type of treament is at least one order of magnitude smaller than by that due to other techniques. Moreeover, laser beam is capable of reaching practically any point of the surface whatever it is narrow or difficult to reach by other techniques. The current work investigates the possibility of improving certain mechanical properties of both technically pure aluminum and A1-4o/oSi alloy, using ruby laser of 3 xl 05 W/cm2 power density. The surface of the investigated materials has been impregnated by SiC particles of varying size ranges, with or without firrther alloying of the surface with Titanium powder addition to the impregnated mixture. The laser treatment included coating one surface of each specimen of SiC particles by means of a binder added at a certain ratio (with or without Ti additions to the mixture). The coated surface was then subjected to the laser beam, which melted a layer I OO-150Jilll thick. Due to hydrodynamic effects the melt mixes with SiC particles and dissolves some or all of the added Ti and rapidly solidifies forming a thin layer distinct in properties from the original surface. Two groups of specimens were used in this study. The first group was treated by impregnating SiC particles of one size range with or without Ti-additions. Various numbers of laser pulses have been applied increasmg in a geometrical progression (1-2-4-8 pulses). These specimens were used for the study of the effect of varying: 1) the chemical composition of the substrate materials ;2) the number of laser pulses :and 3) the effect of Ti additions to the impregnating mixture on the microstracture and microhardness of the treated zones. The specimens of the 2nd group were coated by a square network of laser treated zones each 1.5mm in diameter. These specimens have been used to study :1) the effect of the chemical composition of the substrate material ;2) the size of the SiC particles and 3) the effect of Ti addition to the mixture on the wear perfomance of the treated specimens. Identical specimens have been used to determine the solubility of Si into the aluminum phase during the test by means of x-ray diffraction. This dissolved Si is partly responsible for the increase ID microhardness and wear resistance of the investigated specimens. The results show the positive effect of the applied treatment on the properties and preformence of technically pure AI and A-4%Si alloy. The materials microhardness within the treated zones has been increased by a factor of 2.7 and 2.4 for pure Al and Al-4%Si substrates, respectively. The microstructure of the treated zones became more homogeneous and the penetration of SiC particles into them has been increased with increasing the number of the applied laser pulses. The wear resistance of pure Al has been increased by a factor of 73.6 due to laser assisted impregnation, while that of AI-4%Si by afactor of 42.5. Wear resistance was found to increase with I) Si addition to the base metal; 2) Ti addition to the impregnated mixture, and 3) increasing the SiC particle size. This thesis is a part of a wider study that deals with surface treatment of Al and AI-Si alloys undertaken in our laboratry. Such study proved how effective the laser alloying and impregnation of such alloys in improving some of their mechanical properties which are important in industrial application, especially in internal combustion engine design.
أسماء عبد الرزاق وهرة (2002)

تمت دراسة تأثير أيون الصوديوم على الخواص الفيروكهربائية للمركب (NaxBa1-xTiO3) بقيم (x=0.0,0.3,0.4,05)، الذي تمّ تحضيره بطريقة (تحضير المواد السيراميكية الالكترونية المنشورة والمألوفة). التأثير لدرجة الحرارة في المدى (RT-160ºC) والتردد في المدى (0.01,0.1,1KHz) على السماحية الكهربائية، وكذلك على الفقد العزلي الكهربائي، في الوسط الفيروكهربائي. نتائج أشعة –X [XRD]. تبين أن العينات النقية والمطعمة تتشكل في التركيب البلوري المتماثل عند درجة حرارة (1100ºC). عند درجات حرارة الأعلى من نقطة كوري، قيم السماحية النسبية تحقق قانون "كوري وايز" في المدى الباراكهربائي. طاقة التنشيط لكل العينات تمّ حسابها من منحنى آرهينيوس. Abstract The effect of sodium doping was studied on ferroelectric properties of (NaxBa1-xTiO3) with x= 0.0, 0.3, 0.4 and 0.5 prepared through solid-state route. The effect of temperatures in the range of (RT-160ºC), frequencies (0.01, 0.1 and 1 KHz), and doping ration on the dielectric permittivity and dielectric loss were studied in ferroelectric region. The X-ray diffraction [XRD] results indicate that pure and doped samples crystallize in to tetragonal symmetry on heat treatment at (1100ºC). Above the Curie temperature, the relative permittivity follows curi-weiss law in the paraelectric region. The activation energies were calculated from the (Arrhenius-plot) for all samples.
عبد الرحمن رجب علي النيفرو (2008)

تمت دراسة الغطاء النباتي بالجزء الشمالي لشعبية غريان حيت جُمعت نباتات المنطقة على مدار السنة في حوالي (66) رحلة حقلية في الفترة مابين 1-1-2006 إلى 1-1-2007 وكذلك (18) رحلة تأكيدية في الفترة ما بين2-1-2007 إلى 30-4-2007، ثم جُففت النباتات المُجمعة وصُنفت حسب الطرق العلمية ثم حُفظت بمعشبة كلية العلوم جامعة الفاتح ، وكان عدد الأنواع التي تم تجميعها حوالي (387) نوعاً نباتياً من النباتات الزهرية البرية تنتمي إلى (260) جنساً تحت (58) فصيلة تضمهم (32) رتبة . وكان منها (8) فصائل تابعة لذوات الفلقة الواحدة، و(50) فصيلة من ذوات الفلقتين. وبدراسة النسبة بين عدد الأنواع لكل فصيلة تبين أن الفصيلة النجيلية ((Poaceae هي أكبر فصائل ذوات الفلقة الواحدة، بينما كانت الفصيلة المركبة (Asteraceae) من أكبر فصائل ذوات الفلقتين، كما تم مقارنة الدراسة الحالية للمنطقة بالدراسات السابقة. وقد شمل هذا البحت وصفاَ مختصراَ للطوائف والفصائل التي تم تجميعها في هذه الدراسة، وكذلك وصف دقيق وبناء دوال تصنيفية لعدد (5) أنواع نباتية سٌجلت لأول مرة (New recored) ولم يرد ذكرها في موسوعة النباتات الليبية. كما تم تحديد النباتات المتوطنة والنادرة في المنطقة وفقاَ لدراسة (Qaiser,M.& El-Gadi,A. 1984)، بالإضافة لحصر النباتات الطبية و الرعوية في هذه المنطقة، وقد أُلتقطت صور لجميع الأنواع النباتية التي جُمعت باستخدام آلة تصوير رقمية ، كما وُصفت منطقة الدراسة من حيت الموقع،التضاريس،البناء الجيولوجي وكذلك عناصر المناخ التي لها علاقة بالعينات النباتية في بداية هذا البحت. Abstract This study has intended to cover the area of the northern part of shabiat Garian. In this survey (66) field trips have been conducted during Janury 2006 to January 2007. Moreover, (18) field trips have been confirmed in January 2007 and April 2007. The collected plant species were subjected to the ordinary herbarium procedures. As a result, a list of flowering plants in the study area have been prepared. A total number of (387) species belong to (260) genera, (58) families and (32) orders were recorded Eight families belong to Monocotyledons and Fifty families belong to Dicotyledons. The analysis of the flora in relation to the total number of species and genera belonging to each family revealed that the family Poaceae was the largest family in class Monocotyledoneae (Liliopsida) while the family Asteraceae is the largest family in class Dicotyledoneae (Magnoliopsida). A comparison between the current study and the previous studies were conducted, with an addition of a brief description of the orders and families surveyd in this study .There were (5) species recorded for the first time. Then species were provided with a key and detailed description, as well as (6) endemic were determined according to the study of Qaser&EL-Gadi (1984), in addition to the list of medicinal plant and rare species. Photographs of all species collected in this survey were taken by digital camera, and general back ground about the study area was out-lined including geographical location ,geology, geomorphology, soil & climate was prepared.
شهوب محمد أمحمد ألاحمر (2008)