The most common three-phase problem in porous media is the flow of air and water. This is for example found in the unsaturated zone, where water infiltrates through partly saturated pores to the groundwater. Liquid flow in the unsaturated zone is controlled by a combination of gravitational, capillary, and viscous forces. The mechanical behaviour of partially saturated soils can be very different from that of fully saturated soils. It has long been established that for such soils, changes in suction do not have the same effect as changes in the applied stresses, and consequently the effective stress principle is not applicable. Conventional constitutive models, which are based on this principle, are therefore of limited use when analyzinggeotechnical problems that involve the presence of partially saturated soil zones. In this paper, Al-Mdaina trial embankment was the problem analysed. The finite element programs SIGMA/W and SEEP/W were used, and eight noded isoparametric quadrilateral elements were used for modelling both the soil skeleton and pore water pressure. Parametric study was carried out and different parameters were changed to find their effects on the behaviour of partially saturated soil. Theparameters include the modulus of elasticity and permeability of the soil. It was concluded that the effect of modulus of elasticity on the behaviour of unsaturated soil is apparent at early stages of consolidation and diminishes when the time proceeds. When the clay layer consists of soft clay (Esoil <10000 kN/m2), the effect of unsaturated soil is apparent, while the effect of the modulus of elasticity diminishes when the soil is stiff.

المسالة ثلاثية الطور الأكثر شيوعا في الأوساط المسامية هي جريان الهواء والماء. وهذا على سبيل المثال يوجد في المناطق غير المشبعة، عندما ينفذ الماء خلال مسامات مشبعة جزئيا إلى الماء الأرضي. جريان السائل في المنطقة غير المشبعة يسيطر عليه بواسطة علاقة مركبة من قوى الجاذبية والخاصية الشعرية وقوى اللزوجة. يمكن أن يكون السلوك الميكانيكي للترب المشبعة جزئيا مختلفا جدا عن سلوك الترب المشبعة كليا. لقد ثبت منذ زمن طويل انه لمثل هذه الترب لا يكون التغير في الامتصاص له نفس تأثير التغير في الإجهاد المسلط، وكنتيجة لذلك فان مبدأ الجهاد الفعال لا يكون قابلا للتطبيق. لذلكتكون العلاقات التكوينية التقليدية والتي تستند على هذا المبدأ محدودة الاستخدام عند تحليل المسائل الجيوتكنيكية المتضمنة وجود مناطق تربة مشبعة جزئيا. في هذا البحث تم تحليل مسألة سدة المدينة التجريبية. استخدم برنامجا العناصر المحددة وتم استخدام عناصر رباعية الأضلاع بثماني عقد لتمثيل هيكل ،( SEEP/W) و ( SIGMA/W) التربة و ضغط ماء المسام. أجريت دراسة معاملات و غيرت قيم معاملات متعددة لإيجاد تأثير هذه و معامل (E) العوامل على سلوك التربة المشبعة جزئيا.و تتضمن هذه العوامل معامل مرونة التربة .(k) النفاذية توصل البحث إلى أن تأثير معامل المرونة على سلوك التربة غير المشبعة يظهر في المراحل الأولى من عملية الانضمام ويتلاشى مع تقدم الزمن. وعندما تتكون طبقة التربة من طين رخو يكون تأثيره واضح في التربة غير المشبعة بينما يتلاشى هذا التأثير عندما تكون التربة قوية

Consolidation --- Unsaturated soil --- Finite elements --- Embankment.

In the present work, three transition metal oxides; tungsten trioxide (WO3), zirconium dioxide (ZrO2) and nickel oxide (NiO) were prepared as thin films. Spray pyrolysis and magnetron sputtering techniques were employed to deposit these thin films on indium-doped tin oxide (ITO) coated glass substrates. The prepared samples were characterized by x-ray diffraction, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-visible spectroscopy. The smart window (device) with the configuration: glass/ITO/WO3/ZrO2/NiO/ITO/glass was fabricated and characterized by UV-visible spectroscopy. This device was tested by applying ±5V and high optical transmittance modulation at about 30.93% was observed.

Electrochromic material --- Smart window --- Thin films --- Metal oxides

In this work, the current-voltage characteristics of dc plasma discharges were studied. The current-voltage characteristics of argon gas discharge at different inter-electrode distances and working pressure of 0.7mbar without magnetrons were introduced. Then the variation of discharge current with inter-electrode distance at certain discharge voltages without using magnetron was determined. The current-voltage characteristics of discharge plasma at inter-electrode distance of 4cm without magnetron, with only one magnetron and with dual magnetrons were also determined. The variation of discharge current with inter-electrode distance at certain discharge voltage (400V) for the cases without magnetron, using one magnetron and dual magnetrons were studied. Finally, the discharge current-voltage characteristics for different argon/nitrogen mixtures at total gas pressure of 0.7mbar and inter-electrode distance of 4cm were presented.

Plasma discharge --- Magnetron --- Glow discharge --- Sputtering

In this work, novel design of closed-field unbalanced dual magnetrons system was employed in a DC reactive sputtering system to prepare silicon nitride nanostructures. Two types of silicon wafers (n- and p-type) were sputtered in presence of nitrogen gas to deposit nanostructured silicon nitride thin films on glass substrates. The prepared nanostructured were polycrystalline with six dominant crystal planes: (101), (110), (200), (232), (301) and (321). The surface roughness of the sample prepared at inter-electrode distance of 4cm was higher than other samples prepared at smaller or larger distances and the average and R.M.S roughness were 0.777 and 1.03 nm, respectively. The nanoparticles of minimum size of 30nm were formed and recognized as individual accumulated particles. Two bands of significant absorption were observed around 960 and 1086 cm-1, those are attributed to the Si-N-Si vibration mode in Si3N4 molecule. An absorption peak was observed at 389nm, which is attributed to the quantum size effect of nanostructures. The refractive index of the prepared Si3N4 samples was determined to be 1.38-2.1 and the energy band gap was ranging in 5.1-5.2 eV. The energy band gap was found to increase with decreasing thickness of the prepared film. The wide energy band gap of Si3N4 nanostructures makes them good candidate, as similar as AlN, BN and GaN, for power electronics and optoelectronics operating at high temperatures.

Silicon nitride --- Nanostructures --- Reactive sputtering --- Magnetron sputtering

In this work, experimental results on Langmuir probe diagnostics of low-pressure glow discharge plasma using argon-nitrogen mixtures are presented. The effect of variation in working pressure on the current-voltage characteristics of Langmuir probe diagnostics in unmagnetized glow-discharge plasma was introduced. The current-voltage characteristics of Langmuir probe diagnostics in glow-discharge plasma were studied at working pressure of 0.7mbar and three different cases (no magnetron, using one magnetron at the cathode, and using dual magnetrons). Similarly, the current-voltage characteristics of Langmuir probe in glow-discharge plasma at three different positions of the Langmuir probe inside plasma volume were presented. The variation of electron temperature and density in plasma with working gas pressure at the center point between the electrodes when dual magnetrons were used was determined. As well, the effect of mixing nitrogen with argon on the Langmuir probe characteristics at total working pressure of 0.7mbar and inter-electrode distance of 4cm was studied.

Langmuir diagnostics --- Plasma parameters --- Glow discharge --- Sputtering