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Research Publications (Engineering and Built Environment)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/215

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Subject: search.filters.subject.Methodology

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    Optimization of photo-catalytic degradation of oil refinery wastewater using Box-Behnken design
    (Korean Society of Environmental Engineers, 2019-02-15) Tetteh, Emmanuel Kweinor; Naidoo, Bisetty Dushen; Rathilal, Sudesh
    The application of advanced oxidation for the treatment of oil refinery wastewater under UV radiation by using nanoparticles of titanium dioxide was investigated. Synthetic wastewater prepared from phenol crystals; Power Glide SAE40 motor vehicle oil and water was used. Response surface methodology (RSM) based on the Box-Behnken Design was employed to design the experimental runs, optimize and study the interaction effects of the operating parameters including catalyst concentration, run time and airflow rate to maximize the degradation of oil (SOG) and phenol. The analysis of variance and the response models developed were used to evaluate the data obtained at a 95% confidence level. The use of the RSM demonstrated the graphical relationship that exists between individual factors and their interactive effects on the response, as compared to the one factor at time approach. The obtained optimum conditions of photocatalytic degradation are the catalyst concentration of 2 g/L, the run time of 30 min and the airflow rate of 1.04 L/min. Under the optimum conditions, a 68% desirability performance was obtained, representing 81% and 66% of SOG and phenol degradability, respectively. Thus, the hydrocarbon oils were readily degradable, while the phenols were more resistant to photocatalytic degradation.
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    A methodology to design fibre reinforced laminated composite structures for maximum strength
    (Elsevier, 2003) Walker, Mark; Smith, Ryan E.
    A procedure to select the optimal fibre orientations and determine the maximum load carrying capacity of symmetrically laminated fibre reinforced composite structures is described. Cylindrical shells subject to combinations of torque and in-plane forces are used to illustrate the methodology and are optimally designed for maximum strength. Torque tubes are generally used as control mechanisms, for example, in the tail fins of aircraft. The finite element method, based on Mindlin plate and shell theory, is used in this application in conjunction with an optimisation routine in order to obtain the optimal designs. The methodology consists of two stages; the objective of the first is to maximise the strength of the cylindrical shells by determining the fibre orientations optimally while the objective of the second stage is to maximise the in-plane compression loading subject to a failure criterion. The effect of different shell aspect ratios, wall thickness, layer numbers and boundary conditions on the results is investigated.
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    A technique for optimally designing fibre-reinforced laminated plates under in-plane loads for minimum weight with manufacturing uncertainties accounted for
    (Springer, 2006) Walker, Mark; Hamilton, Ryan Jason
    A procedure to design symmetrically laminated plates under buckling loads for minimum mass with manufacturing uncertainty in the ply angle, which is the design variable, is described. A minimum buckling load capacity is the design constraint implemented. The effects of bending–twisting coupling are neglected in implementing the procedure, and the golden section method is used as the search technique, but the methodology is flexible enough to allow any appropriate problem formulation and search algorithm to be substituted. Three different tolerance scenarios are used for the purposes of illustrating the methodology, and plates with varying aspect ratios and loading ratios are optimally designed and compared.
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    A methodology for optimally designing fibre-reinforced laminated structures with design variable tolerances for maximum buckling strength
    (Elsevier, 2005) Walker, Mark; Hamilton, Ryan Jason
    A procedure to design symmetrically laminated structures for maximum buckling load with manufacturing uncertainty in the ply angle—which is the design variable, is described. It is assumed that the probability of any tolerance value occurring within the tolerance band, compared with any other, is equal, and thus the technique is aimed at designing for the worst-case scenario. The finite element method is implemented and used to determine the fitness of each design candidate, and so the effects of bending–twisting coupling are accounted for. The methodology is flexible enough to allow any appropriate finite element formulation and search algorithm to be substituted. Three different tolerance scenarios are used for the purposes of illustrating the methodology, and plates with varying aspect and loading ratios, as well as differing boundary conditions, are chosen to demonstrate the technique, and optimally designed and compared.