Browsing by Author "Nasr Azadani, Meysam"

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    Modelling Heat Transfer in an Extruder for Recycling Plastics into Filaments for use in Additive Manufacturing
    (2022-08-10) Nasr Azadani, Meysam; Akinlabi, Esther; Whitehead, Timothy; Oyinlola, M. A.
    Global production of plastic increased by 500% over the last 30 years and it is expected to continue to grow to 850 million tons/year by 2050. Plastic use results in a substantial environmental burden due to both land and water pollution as plastics take 10 to 450 years to decompose in landfills. This has resulted in increased calls for innovative ways to recycle plastics, one of which is a decentralised solution where wasted plastics are recycled into filaments for 3D printing. This has been identified as a promising solution, especially for low-income communities in the global south where waste management infrastructure is inadequate. However, studies have highlighted the need for more research and development in the extruder design and operation, especially in terms of optimising temperature distribution and the cooling rate in order to prevent poor filament quality and inconsistent filament diameter. This paper describes the modelling of the temperature distribution and cooling rate of an extruder. The innovation is that the extruder is designed to be built and operated in low-income settings of the global south using locally available materials and skills. The aim of the work is to develop a mathematical model for evaluating the thermal distribution in the extruder as well as optimise the cooling rate conditions. The model is useful for optimising the operating conditions such as ambient temperature, extrusion temperature, extrusion speed, cooling rate and spooling mechanism.
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    A review of current challenges and prospects of magnesium and its alloy for bone implant applications
    (Springer, 2022-03-03) Nasr Azadani, Meysam; Kingsley Bowoto, Oluwole; I. Oladapo, Bankole; Zahedi, S. A.
    Medical application materials must meet multiple requirements, and the designed implant must mimic the bone structure in shape and support the formation of bone tissue (osteogenesis). Magnesium (Mg) alloys, as a “smart” biodegradable material and as "the green engineering material in the 21st century", have become an outstanding bone implant material due to their natural degradability, smart biocompatibility, and desirable mechanical properties. Magnesium is recognized as the next generation of orthopaedic appliances and bioresorbable scaffolds. At the same time, improving the mechanical properties and corrosion resistance of magnesium alloys is an urgent challenge to promote the application of magnesium alloys. Regardless, the excessively quick deterioration rate generally results in premature mechanical integrity disintegration and local hydrogen build-up, resulting in restricted clinical bone restoration applicability. The condition of Mg bone implants is thoroughly examined in this study. The relevant approaches to boost the corrosion resistance, including purification, alloying treatment, surface coating, and Mg-based metal matrix composite, are comprehensively revealed. These characteristics are reviewed in order to assess the progress of contemporary Mg-based biocomposites and alloys for biomedical applications. The fabricating techniques for Mg bone implants also are thoroughly investigated. Notably, laser-based additive manufacturing fabricates customised forms and complicated porous structures based on its distinctive additive manufacturing conception. Because of its high laser energy density and strong controllability, it is capable of fast heating and cooling, allowing it to modify the microstructure and performance. This review paper aims to provide more insight on the present challenges and continued research on Mg bone implants, highlighting some of the most important characteristics, challenges, and strategies for improving Mg bone implants.