الزهراني، عائشة حسين منصور

Herein, we reported the efficient synthesis of new azoles as bio-functional analogs, employing the easily obtainable N-acetyl-3,5-diphenyl-4,5-dihydro-1H-pyrazole-1-carbothioamide (149), 3-(3,5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)-5-methyl-1H-1,2,4-triazole-1-carbothioamide (151) and 1-(3-(dimethylamino)acryloyl)-3-(4,5-dihydro-3,5-diphenyl pyrazol-1-yl)-5-methyl-1H-1,2,4-triazole (170), as a versatile precursors in moderate yields. Then, the reactivity of the terminal carbothioamide, thiazole and acetyl tags, was exploited in a series of manipulations encompassing cyclocondensation for the modular synthesis of new pharmacophoric motif probes. The structures of the newly synthesized vi compounds were elucidated based on their IR, 1H NMR, 13C NMR mass spectral and elemental analysis. Finally, some selected newly synthesized compounds were screened for their in vitro antibacterial activity against two gram-positive species namely Staphylococcus aureus RCMB 0100010 (SA) and Bacillus subtilis RCMB 010067 (BS) and two gram-negative species Pseudomonas aeuroginosa RCMB 010043 (PA) and Escherichia coli RCMB 010052 (EC). They were also tested for their in vitro antifungal activity against two fungal species namely; Aspergillus fumigatus RCMB 02568 (AF) and Candida albicans RCMB 05036 (CA). The preliminary bioassay results indicate that, the majority of the tested compounds exhibited significant anti-microbial activity against the tested microorganisms. Compounds 160, 159, 166, 178, 170, 151 and 150 were found to be the most potent against the tested microorganisms with MIC ≤ (12.25 μg/ mL), in decreasing order .that conjugates bearing thiazole moiety as well as, those with N-substituted electron-withdrawing groups, exhibited higher potency than the rest of other compounds. Keywords: Pyrazoles, N-heterocycles, azoles, N-acetylcarbothioamide, anti-microbial activity.

الزهراني، صالح مطر سعيد

It has been approximately 50 years since researchers first began exposing polymeric materials to ionizing radiation, and reporting the occurrence of cross-linking and other useful effects. Today, a substantial commercial industry is in place based on processing of polymers with radiation. Innovation in this field has by no means ended; important new products made possible through radiation technology continue to enter the marketplace, and exciting new innovations in the application of radiation to macromolecular materials are under exploration at research institutions around the world. In this work we care both the successful radiation processing technologies now in use, and new material radiation technologies that are emerging from research laboratories. An objective of this work is to provide workers , and composite scientists in general, with an overview on the status of progress toward commercial products and technologies in the broad area of radiation processing. More recently, radiation curing of polymer/ceramic composites has begun to come into use. The material prepared by this process has significantly better stability, high-performance and high-temperature applications than polymer only. This technology has been commercialized. More recently, this approach has been extended to the production of Polystyrene/ferrite composite. This material is being explored for use in aggressive environments such as nuclear power plants, high tech electronic devices, integrated capacitors and aerospace applications. The present work is to study gamma radiation effect during composite preparation on the physical, structural, morphology, thermal and electrical properties. The Ni0.6Cd0.4Fe2-xSmxO4 was prepared using a conventional sintering ceramic process. Ferrite product and Styrene was mixed and achieve polymerization process by gamma irradiation at 50 kGy. The conclusions derived from study characteristics of PS/ Ni0.6Cd0.4SmxFe2-xO4 composite are summarized as follow : The diffraction peaks were shifted to different positions of Bragg's angle as the Sm content increases. X-ray patterns show single spinel phase for all investigated samples. Stability of the crystalline structure and no phase transition are found due to irradiation. The bulk density decreases, X-ray density increase and porosity increase with increasing Sm contents before and after irradiation. The lattice parameter increases after irradiation and became nonlinear dependence with increasing of Sm content. The theoritical lattice parameter ath. has values near aex at low concentration of Sm , but are slightly different at higher concentration of Sm. The tetrahedral radii rA remains constant with Sm concentration but octahedral radii rB increases before and after irradiation. Value of the shortest distance between B site and O2- ions (q) and the shortest distance between A site and the O2- ions ( p) decrease after irradiation.The distortion of the lattice increases by increasing Sm content.No significant changes after irradiation in the values of oxygen positional parameter (u)and deviation constant (δ).The average crystallite size tm increase with increasing of Sm content before irradiation and decrease with increasing of Sm content after irradiation but the crystallite size generally increase after irradiation at the same Sm concentration. The grain size shows increasing trend with gamma irradiation . The PS nearly coat the grains and so their boundaries become faint and not sharp.The gamma radiation transfer Fe3+ to Fe2+ due to its ionizing effect .The Fe 2+ occupy octahedral site and the stretching vibration of its bond with oxygen (Fe 2+- O2- ) gives absorption at about 462 Cm-1 near octahedral absorption at 392 Cm-1 .The PS/ Ni0.6Cd0.4SmxFe2-xO4 composite become thermally more stable than pure polystyrene. Introducing ferrite reduces the rate of decomposition. The activation energy of conduction Eσ has a small values in the range of hopping conduction mechanism .The Sm content increases the Curie point. Resistivity of PS/ferrite composite increase by about 109 order of magnitude than the ferrite. The electrical resistivity has three regions with increasing temperature, below Tg, above Tg, belongs to ferrite conduction mechanism at high temperature.

المالكي، حنان موسى عبيد

Hydrogen gas is now considered as a source of efficient, clean, and renewable energy capable of addressing global and environmental challenges. It is therefore one of the most likely future fuels to diminish our dependence on fossil fuels. In industry, steam methane reformer method is widely used to generate hydrogen, carbon monoxide, and natural gas. However, the main disadvantage of this method, besides its requirements of high-energy (heat) input, is the production of CO2 gas as a by-product. CO2-free hydrogen can be produced at room temperature via water electrolysis. For this process to be efficient, an electro catalyst capable of reducing the over potential of the hydrogen evolution reaction (HER), the reductive half reaction of the water splitting process, and accelerating its kinetics should be used. Platinum-based materials are the most stable and efficient electro catalysts for the HER. However, these materials are highly expensive and therefore increase the cost of water electrolyzes. The objective here is to fabricate new, highly efficient, stable, and inexpensive electro catalysts for the HER for CO2-free H2 generation . The goal of this work was also to improve the performance of TiO2 nanomaterials by increasing their optical and electrical activities by shifting the onset of the response from the UV to the visible-light region. Among the several ways to achieve this goal, doping TiO2 nanomaterials with other elements (e.g. metals) was selected to narrow the band gap and enhance the optical and electrical properties of TiO2 nanomaterials. In this work, we have prepared RE-doped TiO2 nano-catalysts, characterized them and studied their properties, and the electrical ones in particular. To achieve this purpose, a new and facile synthesis method of RE- doped titanium dioxide (RE-TiO2) nanoparticles (NPs) at different atomic concentrations of RE is presented. This novel approach allows one to produce titanium dioxide nanoparticles owing to a modified solvothermal process that makes use of Titanium(IV) . The structure and morphology of the TiO2 nanoparticles have been characterized by using Fourier transform infrared spectroscopy (FTIR), thermo gravimetric-differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX) and high-resolution transmission electron microscopy (HRTEM). Afterthen, the obtained TiO2 nanoparticles-doped Gadolinium and neodymium as effective catalysts for efficient electrochemical hydrogen production. The proposed study of controlling doping will be important in tailoring the material for deliver better performance. The experimental work conducted here revealed promising results for improving the performance of the TiO2 nanomaterial by doping it with RE where the optical activity was enhanced and shifted to the visible region causing an appreciable increase in its effectiveness for electrocatalytic applications. Keywords: Titanium dioxide; RE-doped TiO2 nanoparticle; Band gap; Electrochemical Water Splitting; Hydrogen generation.

المالكي ، حنان موسى عبيد

Hydrogen gas is now considered as a source of efficient, clean, and renewable energy capable of addressing global and environmental challenges. It is therefore one of the most likely future fuels to diminish our dependence on fossil fuels. In industry, steam methane reformer method is widely used to generate hydrogen, carbon monoxide, and natural gas. However, the main disadvantage of this method, besides its requirements of high-energy (heat) input, is the production of CO₂ gas as a by- product. CO₂-free hydrogen can be produced at room temperature via water electrolysis. For this process to be efficient, an electro catalyst capable of reducing the over potential of the hydrogen evolution reaction (HER), the reductive half reaction of the water splitting process, and accelerating its kinetics should be used. Platinum- based materials are the most stable and efficient electro catalysts for the HER. However, these materials are highly expensive and therefore increase the cost of water electrolyzes. The objective here is to fabricate new, highly efficient, stable, and inexpensive electro catalysts for the HER for CO₂-free H₂ generation . The goal of this work was also to improve the performance of TiO₂ nanomaterials by increasing their optical and electrical activities by shifting the onset of the response from the UV to the visible-light region. Among the several ways to achieve this goal, doping TiO₂ nanomaterials with other elements (e.g. metals) was selected to narrow the band gap and enhance the optical and electrical properties of TiO₂nanomaterials. In this work, we have prepared RE-doped TiO₂ nano-catalysts, characterized them and studied their properties, and the electrical ones in particular. To achieve this purpose, a new and facile synthesis method of RE- doped titanium dioxide (RE-TiO₂) nanoparticles (NPs) at different atomic concentrations of RE is presented. This novel approach allows one to produce titanium dioxide nanoparticles owing to a modified solvothermal process that makes use of Titanium(IV) . The structure and morphology of the TiO₂ nanoparticles have been characterized by using Fourier transform infrared spectroscopy (FTIR), thermo gravimetric- differential thermal analysis (TGA-DTA), X-ray diffraction (XRD), X-ray fluorescence (XRF), transmission electron microscopy (TEM), energy dispersive X- ray spectrometry (EDX) and high-resolution transmission electron microscopy (HRTEM). Afterthen, the obtained TiO₂ nanoparticles-doped Gadolinium and neodymium as effective catalysts for efficient electrochemical hydrogen production. The proposed study of controlling doping will be important in tailoring the material for deliver better performance. The experimental work conducted here revealed promising results for improving the performance of the TiO₂ nanomaterial by doping it with RE where the optical activity was enhanced and shifted to the visible region causing an appreciable increase in its effectiveness for electrocatalytic applications.

الوعيل، نجوى عمر سعيد

Aims of the study Most of the previous studies clarified that the effect of vit C against the oxidative /antioxidant changes of MSG has not been investigated before. Therefore, the present study was conducted to determine the protective role of vitamin C against the toxicity of MSG. The body weights, hematological parameters, liver functions biomarker, kidney functions, balance of oxidative stress and antioxidant have been evaluated with /without vit C. This study had four main points to clarify 1) Determination of some blood serum contents. 2) Evaluation of hepatic damage biomarkers enzymes by measuring the activities of lactic dehydrogenase (LDH), alanine aminotransferase (ALT) and total proteins content as well as the levels of cholesterol and high density lipoprotein cholesterol were determined. 3) Evaluation of renal damage biomarkers by measuring the levels of uric acid and creatinine. 4) Investigation of oxidative damage/antioxidant biomarkers such as lipid peroxidation level, free radical scavenger enzymes (superoxide dismutase and glutathione-S-transferase) and levels of non-enzymatic antioxidant (reduced glutathione, ferric reducing antioxidant power and ascorbic acid).

الحارثي ، بشرى حاظر عبدالله

In this thesis, we study the complex lag synchronization (CLS) of chaotic complex nonlinear systems with uncertain parameters. We introduce an application in secure communications in light of the results of CLS. Also, we propose a novel kind of complex synchronization; we call this type "modified complex phase synchronization" (MCPS). We make an application in secure communications based on the results of MCPS. We introduce and analyze a new hyperchaotic complex detuned laser system. We study the dynamics of this system. We combine the two previous types of complex synchronization and introduce a new definition of complex synchronization. We call this type "modified complex phase synchronization with time lag" (MCPSTL). We employ the results of MCPSTL to achieve a simple application in secure communication. The results of this thesis are consistent with the Kingdom’s vision (2030), especially on cybersecurity, given the recent increase in cyber attacks. Various types of synchronization have been applied to secure communications, and this supports our goals and aspirations to provide a secure communication and ensure the confidentiality of information transfer.

الحارثي، بشرى حاضر عبدالله

In this thesis, we study the complex lag synchronization (CLS) of chaotic complex nonlinear systems with uncertain parameters. We introduce an application in secure communications in light of the results of CLS. Also, we propose a novel kind of complex synchronization; we call this type "modified complex phase synchronization" (MCPS). We make an application in secure communications based on the results of MCPS. We introduce and analyze a new hyperchaotic complex detuned laser system. We study the dynamics of this system. We combine the two previous types of complex synchronization and introduce a new definition of complex synchronization. We call this type "modified complex phase synchronization with time lag" (MCPSTL). We employ the results of MCPSTL to achieve a simple application in secure communication. The results of this thesis are consistent with the Kingdom’s vision (2030), especially on cybersecurity, given the recent increase in cyber attacks. Various types of synchronization have been applied to secure communications, and this supports our goals and aspirations to provide a secure communication and ensure .the confidentiality of information transfer

السرحان ، بدرية أسامة

Antibiotic therapy is one of the most important therapies used for fighting infectious diseases and has tremendously enhanced the health aspects of human life since its introduction. Despite the advancements in this therapy, we still live in an era where incidents of antibiotic resistant infections are alarmingly on rise . In total, 50 clinical Escherichia coli isolated from urine of UTI patients were investigated. Their ages ranging from two months to 90 years containing 31 females, 12 males and 7 children. Antibiotic susceptibility of isolates was tested on 25 antibiotics. Our finding showed a resistance to all antibiotic except Meropenem. The percentage of resistance was ranged from 100% for penicillin to 2% for imipenem . In addition, 30% of the isolates appeared as for Extended Spectrum Beta-Lactamase (ESBL) positive. Out of the 50 isolates we noted the existence of 46 profiles and 74% of isolates are considered as multi-drug resistance strains Distribution of antibiotic resistance genes showed that the genes aac(3)-IVand blaSHV were identified in 33.33% of isolates. In addition, the genes qnrA, blaCMY and dfrA1 were founded in 37.25%, 19.60% and 17.64% of the isolates respectively. In total, 17 different genotypes were detected and 12 isolates (24%) do not include any genes in their genomes. 5 medicinal plant essential oils showed activity only in cases of Antibacterial effect of Origanum majorana, Thymus zygis and Rosmarinus officinalisagainst E. coli isolates, while Juniperus communis and Zengiber officinale does not showed any effect. Of the three oils, Thymus zygis showed the highest percentage of antibacterial effect. Antibiofilm activity of essential oils demonstrated that Rosmarinus officinalis essential oil has the higher antibiofilm. activity against E. colifollowed by Thymus zygisand Origanum majorana Based on these results, Thymus zygis, Origanum majorana and Rosmarinus officinalis essential oils could be an alternative to antibiotics which is a natural compound.

الشمراني، ابتسام محمد عبدالرحمن

Bean (Phaseolus vulgaris L.) is considered an important food worldwide and a significant source of nutrients because of its consists of fiber, proteins ,mineral salts and vitamins .Several viruses have been reported to infect bean. The present study was conducted to recognize the suitable motheds for diagnosis of Bean yellow mosaic virus diseases. The obtained results could be summarized in the following points: 1- The virus was isolated from naturally .Infected bean plants grown AL.Makhwah Governorate in Southern region of Saudia Arabia .The virus under study was identified as BYMV according to symptomatology , host range ,physical properties , modes of transmission , serological reactions , cytological studies and molecular biology studies. 2- Host range studies revealed that, BYMV infected seventeen plant species and cultivars belonging to seven families . 3- BYMV was inactivated by 10 minutes exposure to 65°C,withstood dilution between 10-3 to 10-4 and persisted in crude sap at room temperature 4 days. 4- Modes of transmission of BYMV were mechanically and aphid transmitted. Two aphid species.( Aphis faba and Myzus persicae ) 5- could transmit Bean yellow mosaic virus none persistently and Aphis faba was the most effective vector as percentage transmission was 60% . 6- The virus was transmitted through the seeds of the tested bean cultivars and the percentage of seed transmission were between 2-3% . 7- The prevalence of the virus in flower and seed parts indicated that ,BYMV was detected in seed parts (seed coat and embryo ) but not found in cotyledons .On the other hand results showed that, BYMV was detected in flower parts (Sepals, Petals, Anthers and Pistils). The percentage of virus detection in Petals , Anthers and Pistils were higher than in Sepals of infected bean (Phaseolus vulgaris cv.Elixir). 8- Positive reactions were obtained only with the virus isolate and its corresponding antiserum using indirect ELISA , provided further evidence that the virus isolate is BYMV. 9- Immunological detection of BYMV was performed by using tissue blot immunoassay (TBIA) and dot blot immunoassay (DBIA) on nitrocellulose membranes . 10- Light microscopy examinations revealed amorphous cytoplasmic and crystalline inclusions in bean plants infected with BYMV. 11- Ultra structural changes in the deformed chloroplasts and grana were severe affected, the chloroplats were more affected in this stage , swollen, irregular, rupture lamella, crash grana and combination with each in the form of amoebic . Cylindrical cytoplasmic inclusions were appeared as pinwheels. The nucleus was elongated irregular with spindle like shape and the chromatin was separately in on side ,were found by electron microscopy in the cross section of infected tissues. 12- Experiments were carried out to scrutinize the depressive effect in the mitotic process of Vicia faba L. when infected with Bean yellow mosaic virus. Remarkably, there was a progressive decrease in mitotic indices and increase in the total percentage of abnormalities due to infection of bean yellow mosaic virus. Types of abnormalities revealed the induction of spindle disturbance, stickiness, laggards, fragments, bridges and micronuclei which lead to the loss of genetic material. 13- RT-PCR based assay was applied for detection of the nucleic acid of Bean yellow mosaic virus (BYMV) in infected bean plants 14- Primer BYMV1 and BYMV2 was prepared. This primer was used for isolation of a part of the 3' end of NIb region and the 5' end of the (CP) region gene for BYMV from infected bean plant sample. RT-PCR was used and electrophoresis followed by staining with staining ethedium bromide. The products was 700bp for the primer specific BYMV 15- DNA sequencing and phylogenetic analysis of the 3' end of NIb region and the 5' end of the (CP) region, of a fragment from the Bean yellow mosaic virus showed 99% homology with the same region of the BYMV strain that isolated in Japan. 16- Nucleic acid hybridization using non- radioactive DNA probes through southern blot and dot blot hybridization techniques revealed the sensitivity of this technique for detection of BYMV infected bean plants. 17- Southern blot hybridization process used from the PCR product, was transferred to the nitrocellulose membrane. These products hybridized strongly with their respective nonradioactive-labelled probe to identify the BYMV part of the 3' end of NIb region and the 5' end of the (CP) region gene fragments. 18- The reaction between dig -labeled cDNA specific for BYMV and BYMV-PCR using dot blot technique .Strong positive reaction of dot blot hybridization was observed with bean and faba bean infected with BYMV. Uninfected leaves of bean (negative controls) gave no reaction in dot blot hybridization technique.

اليامي، مبارك راشد

The present study aimed at use both of ELISA and Real Time-PCR for detecting the presence of HBV and HCV in blood samples collected from different regions: Jeddah, Riyadh, Hafer El-Baten and Taif. Determination of the nucleotide sequences of pol gene of HBV was also aimed. A total 45 blood samples were collected from Jeddah (13 samples), Riyadh (10 samples), Hafer El-Baten (6 samples) and Taif (16 samples), and represent the four major locations of KSA. Both of HBV and HCV were detected in the collected blood samples using the BIO ELISA kits specific to both of viruses. The nucleotide sequences of pol gene of HBV was determined using the DNA extracts of +ve ELISA samples. Results conluded that three (represnting 6.66%) and five (represnting 11.11%) blood samples out of the 45 samples collected from the four different regions of KSA were infected with both of HBV and HCV, respectively. As interestingly, both of HBV-DNA and HCV-RNA were not detected in 100% of blood samples of Hafr El-Batten. While the nucleic acids of the two viruses (HBV and HCV) were detected in a minimum one sample and a maximum two samples in Jeddah, Riyadh and Taif regions. In other mean, a total number of three (6.67%) out of the 45 blood samples were +ve via PCR detection of HBV-DNA. It was noted that seven samples out of the 45 blood samples were infected with both of HBV and HCV. Results confirmed that the male was more avaliable to be infected with hepatitis viruses than female. Correlation between age and HBV & HCV infection based on PCR in blood samples collected from different regions of KSA was discussed. Results showed that the partial sequences of polymerase (pol) gene of HBV-isolate 1 (from Jeddah) and 8 (from Taif) were 272 and 676 (GenBank: LC101676.1) nucleotides, respectively, and their analysis gave two ORFs which deduced into 83 and 224 amino acids, respectively. Percent homology and differences between the two sequences and that of partial sequence of pol gene of 8 overseas strains of HBV in GenBank were discussed.

الحصيني، إيمان محمد أحمد

Cationic surface active agents are important type of surfactants due to their incorporation in several applications including emulsification, detergency, solubilization,biocides and antitumor activity. In this thesis, the type of cationic tetrahalometallate surfactants (ICu, ICo,IZn, IAs,ILa and IFe) were synthesized based on complexation of metal halides and cetyltrimethyl ammonium bromide(CTAB) by grinding in solid state. The chemical structures of the synthesized compounds were confirmed using several analytical tools including micro elemental analysis to determine the percentage of each element in the structure, FT-IR spectroscopy, Raman-spectroscopy and atomic absorption. The synthesized cationic complexes were evaluated as surface active agents throughout measuring their surface properties including surface tension (γ),critical micelle concentration (CMC), and emulsification power as well as their surface parameters including effectiveness (cmc), maximum surface exess (Γmax) and minimum surface area(Amin). The theromodynamic parameters such as free energy change for adsorption Goads and micellization Gomic were calculated . The synthesized tetrahalometallate surfactants (ICu, ICo,IZn, IAs,ILa and IFe)were evaluated asantitumor activity in vitro for normal cell (BHK) and different tumor cell lines, brest(MCF-7),colon(HCT-116) and liver(HepG-2) Also, the synthesized tetrahalometallate surfactants evaluated as biocides for different microorganisms, including; gram-positive bacteria and gram-negative bacteria. summery of the above work was as follows:- – The elemental analysis showed that the synthesized cationic surfactants are highly pure compounds. – The instrumental tools, FTIR and Raman spectroscopy proved the chemical structure of prepared tetrahalometallate surfactants (ICu, ICo,IZn, IAs,ILa and IFe)whichare accordance to the expected structure. – Atomic absorption showed that the ratio of metal in complexes is as expected. – Surface tension measurement showed surface activity of these compounds in their long chain forms. – Emulsification power of the synthesized surfactants was depend on the chemical structure of the used surfactants in the emulsification process. – The effectiveness (cmc) of the synthesized surfactants showed their good surface activity. The maximum surface excess (Γmax ) and minimum surface area (A min) showed the ability of these compounds to accumulated at interface. – The synthesized metallosurfactants showed antitumor activity towards different tumor cell lines(brest (MCF-7), colon (HCT-116) and liver (HepG-2)). Alsohave no cytotoxicity on normal cell(BHK) – The synthesized IAs showed high antitumor activity for all tested cell lines and lower cytotoxicity for normal cell (BHK) also cobalt complex ICo showed antitumor activity towards (HCT-116) cell line. – Lanthanum complex ILa is the lowest antitumor activity and higher cytotoxicity for normal cell (BHK) than other prepared complexes (ICu, ICo,IAsand IFe). – The rest of the synthesized complexes have low cytotoxicity on normal cell(BHK) and higher antitumor activity for all tested cell lines than CTAB. – The synthesized tetrahalometallate surfactants (ICu, ICo, IZn, IAs,ILa and IFe)tested as antibacterial against gram (+ve)(S. auerus) and gram (–ve)(E. Coli). The result showed that these compounds can be used as antibiotics.

المليص، أحمد صلاح الدين سعد عبدالله

This thesis consists of five chapters, we display them as follow: Chapter 1. In the first chapter we will know the basic concepts, and equations of elasticity of the laws of the stress, displacement, also recognize and types of surface waves, and conclude the chapter for the identification of thermal flexibility, and some distinctive theories. Chapter 2. The objective of this chapter is to investigate the surface waves in fibre-reinforced anisotropic elastic medium subjected to gravity field. The theory of generalized surface waves has firstly developed and then it has been employed to investigate particular cases of waves, viz., Stoneley waves, Rayleigh waves, and Love waves. The analytical expressions for displacement components and stress force are obtained in the physical domain by using the harmonic vibrations. The wave velocity equations have been obtained in different cases. The numerical results are given and presented graphically. Comparison was made with the results obtained in the presence and absence of gravity and parameters for fibre-reinforced of the material medium. The results indicate that the effect of gravity and parameters of fibre-reinforced of the material medium are very pronounced. Chapter 3. The objective of this chapter is to investigate the surface waves in fibre-reinforced thermoelastic medium subjected to gravity field. The theory of generalized surface waves has firstly developed and then it has been employed to investigate particular cases of waves, viz., Stoneley waves, Rayleigh waves and Love waves. The analytical expressions for surface waves velocity and attenuation coefficient are obtained in the physical domain by using the harmonicvibrations. The wave velocity equations have been obtained in different cases. The numerical and graphically results are given for Equation of coupled Thermoelastic Theory (CT), Lord-Shulman Theory (LS), Green – Lindsay Theory (GL) and The linearized G-N theory of type II . Comparison was made with the results obtained in the presence and absence of gravity and parameters for fiber-reinforced of the material medium. The results indicate that the effect of gravity, relaxation times and parameters of fiber-reinforced of the material medium are very pronounced. Chapter 4. In this chapter estimation is done to investigate the gravitational and rotation parameters effects on surface waves in fibre-reinforced thermoelastic media. The theory of generalized surface waves has firstly developed and then it has been employed to investigate particular cases of waves, viz., Stoneley waves, Rayleigh waves and Love waves. The analytical expressions for surface waves velocity and attenuation coefficient are obtained in the physical domain by using the harmonic vibrations and four thermoelastic theories. The wave velocity equations have been obtained in different cases. The numerical results are given for equation of coupled thermoelastic theory (CT), Lord-Shulman theory (LS), Green- Lindsay theory (GL) and the linearized (GN) theory of type II. Comparison was made with the results obtained in the presence and absence of gravity, rotation and parameters for fibre-reinforced of the material media. The results obtained displayed by graphs to clear the phenomena physical meaning. The results indicate that the effect of gravity, rotation, relaxation times and parameters of fiber-reinforced of the material medium are very pronounced.Chapter 5. In this chapter, we studied the effect of the gravity field and magnetic field on surface waves in fibre-reinforced thermoelastic media with initial stress. The theory of generalized surface waves has firstly developed and then it has been employed to investigate particular cases of waves, viz., Stoneley waves, Rayleigh waves, and Love waves. The analytical expressions for surface waves velocity and attenuation coefficient are obtained in the physical domain by using the harmonic vibrations and two thermoelastic theories. The wave velocity equations have been obtained in different cases. The numerical results are given for equation of coupled thermoelastic Lord-Shulman theory (LS) and Green- Lindsay theory (GL). Comparison was made for the results obtained in the presence and absence of gravity field, magnetic field, and parameters for fiber-reinforced of the material media. The results obtained displayed by graphs to clear the phenomena physical meaning. The results indicate that the effect of gravity, magnetic field, relaxation times, and parameters of fiber-reinforced of the material medium are very pronounced.

بو سعيد، امل عبدالله سعيد

Our aim in this thesis is to study Solutions of some Problems in Continuum Mechanics of Magneto-thermoelastic Media. This thesis consists of four chapters will introduce them as follow: Chapter 1: This chapter displays a general introduction, general definitions and fundamental equations for elastic problem. Chapter 2: This chapter shows the effect of gravity, initial stresses, non-homogeneity, rotation and magnetic field on the propagation of shear waves in an isotropic incompressible medium. Formulation governing equations various graphs are plotted to show the effect of direction of propagation, anisotropy, magnetic field, non-homogeneity of the medium and the initial stress on shear waves. The dispersion equations for shear waves are obtained and discussed for different cases. In fact, in the absence of various material parameters, these equations are in agreement with the classical results for an isotropic medium. Chapter 3: This chapter is to study the effects of rotation and three-phase-lag parameters in a micropolar generalized thermo-viscoelastic medium. By employing normal mode analysis, the analytical expressions for the displacement components, stresses and temperature field are obtained in the physical domain. These expressions are also calculated numerically and corresponding graphs are plotted to illustrate and compare theoretical results. ~2~ The effects of rotation, ramp and viscous parameters are also studied. Some particular cases of interest have been deduced from the present investigation. Chapter 4: This chapter is concerned with giving a mathematical model on the propagation of Rayleigh waves in a homogeneous magneto-thermo-viscoelastic, pre-stressed elastic half – space subjected to the initial stresses and rotation. The dispersion equation has been derived for a half-space, when both media are considered as pre-stressed and the effect of rotation and initial stress shown in earlier investigators. Numerical results have been obtained in the physical domain. Numerical simulated results are depicted graphically to show the effect of rotation and magnetic field and initial stress on Rayleigh wave velocity. Comparison was made with the results obtained in the presence and absence of the rotation, initial stress and magnetic field. The study shows that there is a variational effect of magneto-elasticity and rotation, initial stress on the Rayleigh wave velocity.

العتيبي ، هند عبد الله معيض

العتيبي، رفعة عبدالله مبارك

The integral equations take an important place in solving many problems of pure mathematics, mathematical engineering and mathematical physics. There are many different methods to solve the integral equations analytically such as :  Homotopy analysis method (HAM).  Homotopy analysis transforms method (HATM).  Optimal homotopy analysis transforms method (OHATM).  Fractional homotopy analysis transforms method (FHATM). The main aim of this thesis is to obtain approximate analytical solutions for the following integral equations: Volterra integral equations, Abel's integral equations, Integro-differential equations and Volterra integro-differential equations by using HAM , HATM , OHATM & FHATM. We propose a reliable combination between this methods and Laplace transformation method (LTM) to find the analytic approximate solution for integral equations. we show that the proposed method is very efficient and computationally attractive This method is reliable and capable of providing analytic treatment for solving such equations. Integral equations often do not have an analytical solution and should be solved numerically