الحارثي، أروى عواض محمد

Our aim in this thesis is to study some problems of thermoelastic for a half-space without energy dissipation under certain boundary conditions. The thesis consists of four chapters in the current field, we present them as follow

القثامي ، روابي محمد سعيد

Simple, new and accurate spectrophotometric method has been developed for the quantitative determination of azole antifungal drug miconazole nitrate (MCO), in pure form and in pharmaceutical formulation. The method was based on the formation of a yellow colored ion-pair complex between the basic nitrogen of the drug (MCO), and the acid dye namely; methyl orange (MO) in acidic buffer of pH range (3.84-6.04). Beer’s law was obeyed in the range 2-24 μg mL-1 . The correlation coefficient was ≥0.9997 with a relative standard deviation (RSD) of ≤ 0.92. The limits of detection and quantification are also reported . Intra-day and inter-day precision and accuracy of the method have been evaluated. The proposed method was successfully applied to determine the studied drug in their formulation without any evidence for interference from pharmaceutical additives and the results were statistically compared with those of the reference methods by applying student’s t-test and F-test. The accuracy of the method was further ascertained by performing recovery studies via standard–addition method. The proposed method can be confidently applied for quality control and routine analysis of the studied drugs .

المالكي ، فوزية محمد بحان

ظبي ، مرام محمد سالم

One of the most widespread diseases in urinary system is urinary stones. It is a global health problem affect both genders since prehistoric period. Based on the present study, different types of urinary stones were studied . It is well known that, the medical. therapy does not work with some stones , which could lead to the surgical intervention. In order to understand the urinary stone formation mechanism, knowing the composition of stones is the first step to find the right treatment. Fifty different types of urinary stones were collected from different patients at the King Abulaziz specialist hospital . In order to collect more information about the patients, a medical questionnaire was used in order to understand the relationship between the different influence factors and the structures of urinary stones. Investigation of the structural and composition of the urinary stones were carried out using different spectroscopic techniques namely; Energy Dispersive X-ray fluorescence (EDXRF), Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) and differential thermal analysis (DTA). Each technique has its own advantages and disadvantages and they are cooperative in achieving the best results.) samples were crushed using agate mortar and pestle after being washed with distilled Most of the water in order to have a fine powder adopted with the different spectroscopic techniques .. Using EDXRF spectrometer, two different quantitative elemental analysis methods were investigated namely powder using Mylar foil and pressing using a suitable binder . In case of powder analysis method, the urinary stone powder can be used afterwards and it is completely nondestructive. However, the impurities found in the Mylar foil were considered and subtracted from the final quantitative analysis results. This method was found the most suitable in the present work whereas the samples can be used for further physical and chemical characterization. Using the second method, specific amount of the urinary stone sample should be mixed well with pure and suitable binder such as wax, cellulose, or urea. The binders seem to be essential additive in order to prevent caking and to get a stable disc especially when using vacuum environment. Furthermore, the binder should be from light elements to decrease the x-ray scattering as well as the background intensities. The main drawback of this method is the pressed sample cannot be used for further characterization and the required amount of urinary stone samples is not always available. Although the pressed sample method was not used in the present work, optimization of the most suitable binder was investigated. Pure and commercial four types of binder have been used for this purpose namely; cellulose, starch, urea, and wax in order to find out the best and low cost binder that can be used for the pressed sample method. The pure and commercial wax show good result in most photon energy range in the EDXRF spectra. Using powder sample method, nineteen elements were quantitatively determined but these elements are not found in all the urinary stones samples. These elements are Ca, Na, P, S, Mg, Cl, Zn, K, Ti, Sr, Ni, Co, Fe, Cu, Cd, Br, Pb, Se, and Mn. Based on the X-ray Diffraction analysis, the main two type’s urinary stones were calcium oxalate and urea. Other minor types of urinary stone were also found. However, each type has its own composition and its own elemental composition. The main compositions of the urinary stones were confirmed by FTIR..

الغامدي ، رفعة مسفر

censoring is a common phenomenon in life-testing, and reliability studies. The subject of progressive censoring has received considerable in the past few years, due in part to the availability of high speed computing resources, which make it both a feasible topic for simulation studies for researchers and a feasible method of gathering lifetime data for practitioners. The inference is feasible and practical when the sample data are gathered according to a Type-II progressive censored experimental scheme. In many applied sciences such as medicine, engineering and finance, amongst others, modeling and analyzing lifetime data are crucial. Several lifetime distribution have been used to model such kinds of data. For instance, the exponential, Weibull, gamma, Rayleigh distribution and their generalizations. Each distribution has it is own characteristics due specifically to the shape of the failure rate function which may be only monotonically decreasing or increasing or constant in its behavior, as well as non-monotone, being bathtub shaped or even unimodel. in this thesis, we have considered Bayesian and non-Bayseian estimators for extended Lindley distribution parameters, which offers a more flexible distribution for modeling lifetime data, IN CHAPTER I: we present some basic concepts which will be used throughout this thesis. Also we show a historical survey on some studies in theoretical and application which have been made on different progressive censoring. Finally, it contains a description of under-study problem. IN CHAPTER 2 : some classical estimators have been obtained for the Parameters of the extended Lindley distribution using a life-test plan called a progressive Type-II censored data. Asymptotic confidence intervals and bootstrap confidence intervals are also proposed. IN CHAPTER 3:- Bayes point estimators of the parameters extended Lindley distribution based on progressive Type-II censoring scheme with respect to squared error (SE) loss functions. The Bayes estimators cannot be obtained in explicit forms. Approximate Bayes estimators are computed using the idea of (MCMC) methods to generate from the posterior distribution. An analysis of a real and simulate life data sets is presented for illustrative our purposes. Results from simulation studies assessing the performance of our proposed method are included.

البقمي، أسماء محمد راجح

Analysis of infectious disease data is statistically challenging and can be useful for planning and assessing various intervention strategies against infectious diseases. However, the resulting inferences are conditional on whether a model fitted adequately describes the main features of the data. Methods to assess and compare stochastic epidemic models within a Bayesian framework are not yet wellestablished and various approaches are still being investigated. In this thesis, we present a method for model adequacy for stochastic epidemic models. We work with continuous-time SIR (Susceptible-Infective-Removed) epidemic models, and assume that all infection and removal times are available. Throughout this thesis, we evaluate our method using simulated outbreak data. Additionally, we use Markov Chain Monte Carlo (MCMC) techniques to infer model parameters. Under a Bayesian framework, two predictive distributions are examined, namely the predictive distribution of the epidemic final size and the predictive distribution of the epidemic duration. This method involves comparing the observed data with the predicted data using the posterior predictive model checking approach, in which the posterior predictive p-value is used. Our extensive simulation study reveals that the epidemic final size statistic has the ability to recover the true model, however the epidemic duration statistic fails to do that.

السعدي ، منال غازي

In this thesis, based on an adaptive Type-II progressive censoring scheme, we make some statistical inferences (estimation and prediction) for the Gompertz distribution and Generalized Gompertz distribution with the help of an algorithm to explain how we apply methods of estimation and prediction. We used the maximum likelihood estimator and the Bayesian method to estimate the parameters of these distributions as well as some lifetime parameters (reliability and hazard functions). Also, the two-sample Bayesian prediction intervals are used to obtain some estimation for future data based on the past data from the same distribution.

الحربي، فاطمة صالح عبدالله

This study was designed to :- 1- Studying the epidemiology of Fasciola spp. among goats in Taif governorate. 2- Identified the recovered parasites from examined livers of goats. 3- Studing the pathological hepatic lesions induced by bacteria in liver infested with Fasciola and to detect the relationship between these bacterial infections and liver fascioliasis. 4- In vitro studying the effects of some medicinal Herbal drug extracts (Calligonum comosum plant) and triclabendazole (TCBZ) on Fasciola spp. through scanning electron microscope (SEM) examination.

الجعيد، فهد عابد

A photovoltaic (PV) study of dye-sensitized solar cells based on ZnO and ZnO-coated TiO2 photo-electrodes was carried out. The sol-gel spin-coating technique was employed in the preparation and deposition of ZnO. Measured absorbance and transmittance spectra at different ZnO precursor concentrations have revealed clear thickness dependence. There was a small shift of both spectra in the visible range (400nm-800nm), but the transmittance remains above 80% at all precursor concentrations, indicating the suitability of ZnO film to DSSCs. The optical gap was estimated around 0.315 eV without noticeable change with the precursor concentration. For the ZnO DSSC, the I/V characteristics under 1000 W/m2 AM1.5-filtered light have shown dependence on preparation conditions such as ageing before spincoating, annealing before dye-loading and ZnO amount (number of sol drops and/or precursor concentration). Despite attempting to optimize these conditions, only small efficiencies (less than 0.45%) were attained, suggesting that the sol-gel method needs improvement to produce a thick nanoporous film suitable for high  DSSC. As for the ZnO-coated TiO2 DSSC, the I/V characteristics resulted in a remarkably dependent on the ZnO amount. An optimization was achieved, resulting in ZnO amount of a single sol drop at a precursor concentration between 0.1M and 0.2M, which improved  by more than 100% (from ~2% to ~4.5%). The results were interpreted in terms of the formation of an energy barrier upon ZnO coating which reduces the electron back-recombination rate, and thereby enhances the photocurrent without affecting the dye-adsorption efficiency of the TiO2 film.

العتيبي، منى ماطر

In this thesis, we demonstrated, for the first time, aluminum titania nanoparticle (Al-TiO2 NP) composites with variable amounts of TiO2 NPs as nonprecious active catalysts for the electrochemical generation of H2. These materials were synthesized by mixing desired amounts of hydrogen titanate nanotubes (TNTs), fabricated here by a cost-effective approach at moderate hydrothermal conditions, with aluminum powder (purity 99.7%; size 35 μm). The mixture was compacted under an applied uniaxial stress of 300 MPa followed by sintering at 500 °C for 1 h. After sintering had been completed, all TNTs were found to convert to TiO2 NPs (average particle size 15 nm). Finally, Al-xTiO2 NP nanocomposites (x = 1, 3, 5, and 10) were obtained and characterized by scanning electron microscopy/energy-dispersive X-ray, X-ray diffraction, and X-ray photoelectron spectroscopy. The hydrogen evolution reaction (HER) activity of these materials was studied in 0.5 M H2SO4 at 298 K using polarization and impedance measurements. The nanocomposite of chemical composition Al-5% TiO2 NPs showed the best catalytic performance for the HER, with an onset potential (EHER), a Tafel slope (βc), and an exchange current density (j0) of −100 mV (RHE), 59.8 mV decadeˉ¹, and 0.14 mA cmˉ², respectively. This HER activity is not far from that of the commercial platinum/carbon catalyst (EHER = 0.0 mV, βc = 31 mV decˉ¹, and j0 = 0.78 mA cmˉ²). The best catalyst also exhibited good stability after 10000 repetitive cycles with negligible loss in current.

الدماس ، سها إبراهيم صالح

الأسمري ، فاطمة حمود ظافر

to provide undemanding and efficient solar power generation to meet future energy needs. PSCs are considered as promising contender for conventional solar cells technology, where high performance perovskite solar cells have attained power conversion efficiencies (PCEs) over 22% in recent years. The planar (n-i-p) perovskite solar cells have uprising photovoltaic research and improvement because they can be fabricated at low cost in room temperature, besides their flexibility and high efficiencies. This work is consider with the improvement of the performance of planar perovskite solar cells (PSCs) with the addition of CdSe quantum dots (QDs) layers as supporting absorbers. The FTO/TiO2/ CH3NH3PbI3/Spiro-OMeTAD/CNs solar cells with and without different number of layers of CdSe QDs were characterized in terms of their structure, morphology, optical and photovoltaic properties. X-ray diffraction (XRD) and scanning electron microscope (SEM) were utilized to investigate the structure and morphology of the obtained cells. Also, the optical properties of the samples were investigated by using spectrophotometer. Finally, the I-V characteristics of the obtained cells were measured using a solar simulator setup. It has been found from the XRD results that there is no significant changes in the crystalline structure upon the addition of the CdSe QDs layers. However, there is a noticeable increase in the intensity with the increase in CdSe QDs layers because of the accumulation of QDs nanoparticles and this is an agreement with the increase of the particle size seen in the SEM images. Furthermore, the absorption of the perovskite-CdSe QDs composite has been increased in the visible region with increasing the number of QDs layers. The photovoltaic effect has been observed to be improved upon the addition of CdSe QDs layers. The efficiency of the constructed perovskite solar cells increased from to 14.4% by adding 5 layers of CdSe QDs on the top of perovskite layer in the 7.2% solar cells. This was indicated by the increase of life time of the electron when adding more layers of CdSe QDs .The reproducibility of the obtained cells has been tested showing a high performance with the cut ON-OFF of light.

الثقفي، الهام حسن سعد

Glasses in the system 40 %B2O3- (40-x) %GeO2- x% V2O5 –20%Li2O (where x = 2, 4, 6, 8, 10 mol %) were prepared at intervals through the glass-forming composition range. We have characterized the samples from the XRD study. The density measurement made at room temperature. No crystalline phase was observed. The density values showed a decrease with the increase of V2O5 content. The conductivity measurements were carried out as functions of composition, frequency and temperature. Dc and ac Conductivity found to increase as the total vanadium content increased. The ac conductivity exhibited a Jonscher’s universal power law and it is observed that as the temperature increases, frequency exponent (s) decreases. The results of dc conductivity analyzed with reference to three models as activation model, variable range hopping model and small polaron multi-phonon assisted hopping. It was found that small polaron hopping model was applicable at the temperature above D/2 (D : the Debye temperature). The electrical conduction at T > D/2 was due to variable range hopping, however the ac conductivity in present system was analyzed using quantum mechanical tunneling and correlated barrier-hopping vi models. It was found that the correlated barrier hopping models gives plausible fitting to the experimental data of the present system.

الدوسري، عبير عبيد

The present thesis is devoted to study structural and optical properties of niobium pentoxide (Nb2O5) thin films. Nano thin films of Nb2O5 were sputter deposited on glass substrates using RF sputtering technique. The effect of variation RF sputtering powers (150, 175 and 200 W) on the structural and optical properties of as-deposited and annealed ( at 773 K for 6 hrs. in air) Nb2O5 thin films are examined using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) techniques, UVVis- NIR double beam spectrophotometer and Photoluminescence (PL) measurements. X-ray diffraction results revealed that the as-deposited and annealed films are polycrystalline structure. The structures morphology was characterized with atomic force microscopy (AFM) for as-deposited and annealed samples at 773 K . FESEM images of the films showed a uniform distribution of nano-grains. It can be observed that the nano-grains size increasing with increasing RF power. The optical properties of as-deposited and annealed films were studied using their reflectance and transmittance spectra. Transmission and reflection of films were studied by the spectrophotometer measurements at normal incidence of light to determine the dispersion and absorption spectral behaviour, as well as, the high frequency dielectric constant, the lattice dielectric constant optical band gap energy, refractive index, dielectric constants and oscillators’ parameters. The estimated direct optical bandgap energy values are found to be 𝐸" # =3.79 eV ,3.68 eV and 3.74 eV for the as deposited while for the annealed films at 773 K are 𝐸" # =3.82 eV,3.68 eV and 3.74 eV with the increasing of RF sputtering powers (150, 175 and 200 W) respectively. It is observed that the value of real refractive index decreases and increases with the increasing of RF sputtering powers for as-deposited and annealed films respectively. The dispersion curves of the refractive index of Nb2O5 thin films were found to obey the single oscillator and Drude models.

الدوسري ، عبير عبيد محمد

The present thesis is devoted to study structural and optical properties of niobium pentoxide (Nb₂O₅) thin films. Nano thin films of Nb₂O₅ were sputter deposited on glass substrates using RF sputtering technique. The effect of variation RF sputtering powers (150, 175 and 200 w) on the structural and optical properties of as-deposited and annealed ( at 773 K for 6 hrs. in air) Nb₂O₅ thin films are examined using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) techniques, UV- Vis-NIR double beam spectrophotometer and Photoluminescence (PL) measurements. X-ray diffraction results revealed that the as-deposited and annealed films are polycrystalline structure. The structures morphology was characterized with atomic force microscopy (AFM) for as-deposited and annealed samples at 773 K . FESEM images of the films showed a uniform distribution of nano-grains. It can be observed that the nano-grains size increasing with increasing RF power. The optical properties of as-deposited and annealed films were studied using their reflectance and transmittance spectra. Transmission and reflection of films were studied by the spectrophotometer measurements at normal incidence of light to determine the dispersion and absorption spectral behaviour, as well as, the high frequency dielectric constant, the lattice dielectric constant optical band gap energy, refractive index, dielectric constants and oscillators’ parameters. The estimated direct optical bandgap energy values are found to be Edg = 3.79 e V,3.68 eV and3.74 eV with the increasing of RF sputtering for the as deposited while for the annealed films at 773 K are Edg = 8.32 eV,3.68 eV and 3.74 eV powers (150, 175and 200 W ) respectively. It is observed that the value of real refractive index decreases and increases with the increasing of RF sputtering powers for as-deposited and annealed films respectively. The dispersion curves of the refractive index Nb₂O₅ of thin films were found to obey the single oscillator and Drude models