MOD cavities in 60 endodontically treated teeth were restored using six different methods. Copper rings were filled with commercial hard-setting cement and the teeth were placed up to the level of the cemento-enamel junction. The teeth were grouped according to restorative method, mounted in an Instron TT machine, and the buccal walls subjected to a slowly increasing compressive force until fracture occurred. The force of fracture of the walls of each tooth was recorded and the results in the various groups compared. All teeth fractured in a similar manner irrespective of the restorative method used. All groups restored with the newer bonding system had higher resistance to fracture than those restored with an acid etch chemically cured composite resin technique. The groups restored with Den-Mat Tenure Core Paste or a Variglass VLC base and Prisma APH were significantly stronger than the acid etch Concise restored teeth (P < 0.05). No statistically significant differences were found between the other groups (P > 0.05).
The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications.
This study uses linear programming to develop a methodology for selecting the best raw material mix in an ASCOM cement plant in Egypt. In cement factories, this type adheres to Egyptian chemical composition criteria for raw feed (e.g. 82.5% calcium carbonate, 14.08% silica, 2.5% alumina and 0.92% iron oxide). Furthermore, the model is bound by industry-specific characteristics (e.g. lime saturation factor, silica modulus, alumina modulus and loss of ignition). The results reveal that the model is able to accurately reproduce the mixing of high-quality feed with varying constituent percentages. It is also capable of determining the combining limitations of each ingredient. Furthermore, it demonstrates optimality for additive sourcing short-term planning and capping limestone quality to meet changeable component combinations. Additionally, improving the raw mix reduces limestone feed quality from 51 to 50.6%, resulting in the inclusion of extra limestone reserves.
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