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Eltaher, Mohamed A.,Almalki, Talaal A.,Ahmed, Khaled I.E.,Almitani, Khalid H. Techno-Press 2019 Advances in nano research Vol.7 No.1
This paper focuses on two main objectives. The first one is to exploit an energy equivalent model and finite element method to evaluate the equivalent Young's modulus of single walled carbon nanotubes (SWCNTs) at any orientation angle by using tensile test. The calculated Young's modulus is validated with published experimental results. The second target is to exploit the finite element simulation to investigate mechanical buckling and natural frequencies of SWCNTs. Energy equivalent model is presented to describe the atomic bonding interactions and their chemical energy with mechanical structural energies. A Program of Nanotube modeler is used to generate a geometry of SWCNTs structure by defining its chirality angle, overall length of nanotube and bond length between two adjacent nodes. SWCNTs are simulated as a frame like structure; the bonds between each two neighboring atoms are treated as isotropic beam members with a uniform circular cross section. Carbon bonds is simulated as a beam and the atoms as nodes. A finite element model using 3D beam elements is built under the environment of ANSYS MAPDL environment to simulate a tensile test and characterize equivalent Young's modulus of whole CNT structure. Numerical results are presented to show critical buckling loads, axial and transverse natural frequencies of SWCNTs with different orientation angles and lengths. The understanding of mechanical behaviors of CNTs are essential in developing such structures due to their great potential in wide range of engineering applications.
Khalid A. Almalki,Ali A. Al-Namazi 대한공간정보학회 2019 Spatial Information Research Vol.27 No.3
Jubail is an industrial city that has registered the highest growth in Saudi Arabia in recent years, and it is important to understand the potential effects of this growth on both the environment and the City’s residents. The collaboration between the industry and the academic researches and scientific technologies would contribute to achieve a proper management to reduce the potential industrial risks on the environment and living organisms. In this study, we used remote sensing technology using Landsat 8 satellite images to calculate and analyze surface temperatures in Jubail Industrial City. Previous observations of Jubail using Landsat 7 satellite images from 2001 demonstrated that a heat island is centered above the industrial area. Heat islands can lead to serious environmental and health issues. The land surface temperatures observed in this study (29–77.2 C) are, to some extent, consistent with those of a previous study (33–85 C); however, increased industrial activity in Jubail has led to an expansion of heat coverage, both inland and offshore. Our study illustrates the importance of remote sensing data for detecting and understanding historical climate change in industrial urban areas, thus providing valuable data for future management planning.
Syed Amir Mahmud,Mike W. Hall,Khalid A. Almalki 한국지질과학협의회 2018 Geosciences Journal Vol.22 No.5
Mineralogical studies were conducted on sandstones of Late Cambrian–Early Ordovician Owen Group, southern West Coast Range, Tasmania, Australia. Several samples were analysed using conventional thin section and point counting techniques, while others were further analysed under a Scanning Electron Microscope with back scattering and Energy Dispersive X-ray Spectroscopy capabilities. The result of petrographic analyses includes provenance, possible sources and controls over coloration in sandstone samples. The sandstones are mainly comprised of quartz, mica, lithic grains (volcanic, metamorphic and sedimentary), clays, zircon, tourmaline, leucoxene, rutile, and chert grains. These were derived from a Proterozoic Tyennan metamorphic and a Middle Cambrian Mount Read Volcanic provenance. Following deposition, sediments underwent severe diagenesis including quartz overgrowth, iron coatings, haematite, chlorite and sericite alterations, linings and cements. Multi-phase haematite-related diagenesis is present and late stage hydrothermal fluid alterations assemblages have severely altered and colored the sediments.