الفهرس 
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Abstract
This thesis investigates the design and performance of a novel municipal solid waste (MSW) bag opener machine, a device that can cut/open multiple bags of waste at once, for the Middle East and North Africa (MENA) region context especially for Egypt. Bag opener machines play a crucial role in the mechanical-biological treatment (MBT) lines to enhance the waste processing performance and increase the material recovery. The main research query is to evaluate and improve the design and performance of the MSW bag opener machine for the Egyptian context. Accordingly, the thesis followed a mixed-methods approach, consisting of MSW characterization studies, bag opener design methodology, blade design and geometry, finite element analysis, and machine fabrication plan.
The waste characteristics in Egypt have undergone an excessive survey to acquire all available data related to the waste composition, size distribution, and mechanical properties. And to complete the picture, a waste characterization study in five different places in Egypt was planned and implemented. In addition, the survey is extended to cover the available designs of the bag opener machines working in different MBT lines in Egypt including two local and two foreign machines to construct a detailed comparison between them and the current proposed design.
The bag opener design methodology proposed a novel design philosophy and assumptions for the bag opener machine, and identified the main parameters and variables that affect the bag opener performance, such as mesh size, capacity, blade size and shape, power transmission method, and speed.
The blade design was developed using the 3-D modeling software, SOLIDWORKS. The blade strength, performance, and durability are assessed using static and fatigue finite element analyses (FEAs) under a pressure of 1 MPa. The blade design methodology mainly comprises two blade models’ groups, each consisting of four models, that differ in their cutting edge dimensions (180 and 200mm) and angles (30°, 45°, 50°, and 60°), and provided the material properties and the boundary conditions for the blades.
The finite element analysis performed static and fatigue simulations on the blades, using different scenarios of blade shape, angle, and fixation methods (loose and tight fixations), and selected the optimal blade model based on the stress, strain, displacement, factor of safety, fatigue load factor, and fatigue life criteria.
The MSW samples from five sites in Egypt showed a high variability in their morphological and mechanical properties, indicating the need for a robust and adaptable bag opener machine. The results indicate that the proposed design can achieve a capacity up to 30 ton/hr with a power consumption of 22 kW. The results include the Von Mises maximum stress, strain, and displacement, as well as, the minimum factor-of-safety (FOS) and the fatigue stress analysis. The best suitable blade model for the bag opener machine is found to be model (G2-D), which has a longer cutting edge length (200mm) and a lower cutting angle (30°). It has a maximum stress of 15.18 MPa and a maximum strain of 5.5x10-5. Also, it has a minimum FOS of 18.12 and a maximum displacement of 8.7x10-3 mm. As for all blade models, it has a life of 106 cycles.
The thesis describes the fabrication process and the equipment used to construct the bag opener machine, based on the optimal blade model and the design parameters. The fabrication plan reveals a time required to implement the machine within 10 to 12 weeks with a cost about 136,000 [USD].