https://repository.sustech.edu/handle/123456789/1316 2026-04-06T05:56:03Z 2026-04-06T05:56:03Z Abd Alfadel, Alzakey Abd Alfadel Mohammed Supervisor, -Shawgy Hussein AbdAlla https://repository.sustech.edu/handle/123456789/28360 2023-04-10T06:58:55Z 2022-07-25T00:00:00Z

Title: Effective Estimate with Self-Similarity for Lebesgue Measure of Some Cantorval Authors: Abd Alfadel, Alzakey Abd Alfadel Mohammed; Supervisor, -Shawgy Hussein AbdAlla Abstract: We obtain the spectrum and an effective estimate for the Lebesgue measure of the preimages of iterates of Farey and Gauss maps. The intervals and dichotomy between Farey fractions and sequence in the limit of infinite level and uniform distribution of the Stern-Brocot are determined. The structure, topology, separation and measure properties of the self-similar sets and Fractals and interated function systems of bounded distortion are characterize. We examine the asymptotic behavior of the Lebesgue measure of sum-level sets of continued function, self-similarity and nonempty interior. The family of self-affin and self-conformal sets with uniqueness, simultaneous and positive Hausdorff measure are studied. The nultigemetric. Subsum sets of sequences with recovering a purely atomic finite measure and Cantorvals with Lebesgue measure of M-Contorvals of Farey type are established. Description: Thesis

2022-07-25T00:00:00Z Ahmed, Ahmed Mohamed Nageeb Alwasela Supervisor, -Mohsin Hassan Abdalla Hashim https://repository.sustech.edu/handle/123456789/28359 2023-04-10T06:50:36Z 2023-01-19T00:00:00Z

Title: New Direction in Derivative Free Optimization Authors: Ahmed, Ahmed Mohamed Nageeb Alwasela; Supervisor, -Mohsin Hassan Abdalla Hashim Abstract: In this thesis, we study a derivative-free trust-region algorithm for large-scale unconstrained optimization, using symmetric-rank1 (SR1) to update the Hessian at every iteration. The centeral finite-difference iterations are used to approximate the gradient of the function. The iterative solution method and truncated Newton method were used to solve the trust-region sub-problem. Its performance is tested on some problems and compared the solutions found by truncated Newton method and iterative solution method. Description: Thesis

2023-01-19T00:00:00Z Fadl, Mahmoud Hassan Osman Supervisor, -Mubarak Dirar Abd-Alla Yagoub https://repository.sustech.edu/handle/123456789/28349 2023-04-03T08:00:49Z 2022-06-28T00:00:00Z

Title: Change of the Electrical Magnetic and Optical Properties of Nano Sodium Chloride Due to the Change of its Nano Structure Authors: Fadl, Mahmoud Hassan Osman; Supervisor, -Mubarak Dirar Abd-Alla Yagoub Abstract: Nano science represents one of the most popular powerful tools for controlling and changing the physical properties of matter. It is now widely used in many applications. One of the most popular known one is the field of electronics, where the optical and electrical properties of matter are important. This encourages to do this work. In this work 8 Na Cl samples were prepared and crushed for different micro sizes and nano sizes using crushing machine. Before that the samples where purified by being dissolved in water that flows through sever and dried using drying machine. Their optical, electrical and magnetic properties were investigated by UV, FTIR and XRD. The ultraviolet - visible (UV) determines absorption coefficient, energy gap and conductivity. Fourier transform infra-red spectrometer (FTIR) determines the chemical energy bonds. The X-ray diffraction (XRD) technique determines the crystal structure as well as the nana structure. The crushing of Nacl into small particles having different micro sizes shows that this causes their physical properties to change. It was found that their nano size increases upon increasing their micro size, where each micro particle consists of aggregates of nano crystals. The absorption coefficient, crystal spacing increases upon increasing the nano and micro size. The energy gap decreases upon increasing the nano and micro size. The optical conductivity also increases for a wide range of wavelengths. The electric conductivity, permittivity, refractive index and magnetic permeability decreases for short wavelengths and increases for long wave lengths upon increasing the nano and micro size Description: Thesis

2022-06-28T00:00:00Z Elhassan, Sanaa Ahmed Abbashar Supervisor, -Mohammed Sulieman Ali Eltoum https://repository.sustech.edu/handle/123456789/28348 2023-04-03T07:46:15Z 2023-01-12T00:00:00Z

Title: Physiochemical Properties of some metal oxides /glycol Nano fluids Authors: Elhassan, Sanaa Ahmed Abbashar; Supervisor, -Mohammed Sulieman Ali Eltoum Abstract: The thermal properties are a primary indicator in the development of energy efficient heat transfer fluids that is required in numerous industry sectors. Recently nanofluid was introduced into the heat fluids to enhance the thermal conductivity of the resulting nanofluids. The aim of this study is to synthesis, characterization and study of thermal properties of metal oxides of Co, Cu and Fe / glycol nanofluids. Metal oxides nanoparticles were prepared using Sol-Gel method; the nanofluids were obtained via dispersing of nanoparticles powder in 40 ml of ethylene glycol by four concentrations (0. 2 – 0.1 – 0. 05 - and 0.025 g) from nanoparticles at room temperature with mechanical agitation. The structures of the prepared Co3O4, CuO, and Fe2O3/glycol nanoparticles were confirmed using XRD technique and UV absorption spectra. The average crystallite size of nanoparticles obtained was as follows: 41.46 nm, 28, 58 nm, 78, 65 nm for Co3O4, CuO and Fe2O3 respectively. Absorption spectra of Co3O4 nanoparticles are show a strong fundamental absorption, edge approximately 496 nm, The UV- Vis spectra of CuO NPs show peak in the range of 200-350nm, and for Fe2O3 NPs the peak appear between 320 and 420 nm. The density increased with increasing particles concentration in the 12 samples nanofluid. All viscosity measurements were conducted using a capillary viscometer; the viscosity experiment was carried out at wide temperatures ranging between 20 and 80C° to determine their applicability in such range. The viscosity data were collected using a programmable rheometer result, increasing the temperature of nanofluids decreases their viscosity. The Differential Scanning Calorimeter (DSC) instrument was used for the measure of heat flux of the prepared metal oxides /glycol nanofluid in the thermal range between 300-500 °C. It was observed that the heat flux of the synthesized nanocomposites increase with increasing temperature and the rate of increase varies from one oxide to another. And from the heat flux data the thermal conductivity of the samples was calculated using Fourier law: in cobalt oxide nanofluids the thermal conductivity increases with temperature, thermal conductivity oscillates at the beginning of heating but is regulated with continued heating, except the concentration (0.2). For the copper oxide nanofluid and iron oxide nanofluid with their four concentrations their thermal conductivity increases with increase the temperature. The heat capacity of all the prepared samples (which is related to the change in temperature), has been calculated and its values change with the change in temperature and increase with the increase temperature and the concentration of nanoparticles. Description: Thesis

2023-01-12T00:00:00Z