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Simulated metamorphosis - a novel optimizer

- Mutingi, Michael, Mbohwa, Charles

  • Authors: Mutingi, Michael , Mbohwa, Charles
  • Date: 2014
  • Subjects: Metamorphosis , Evolution , Optimization , Algorithm , Metaheuristics , Simulated metamorphosis
  • Type: Article
  • Identifier: uj:4972 , ISSN 2078-0966 , http://hdl.handle.net/10210/13073
  • Description: This paper presents a novel metaheuristic algorithm, simulated metamorphosis (SM), inspired by the biological concepts of metamorphosis evolution. The algorithm is motivated by the need for interactive, multi-objective, and fast optimization approaches to solving problems with fuzzy conflicting goals and constraints. The algorithm mimics the metamorphosis process, going through three phases: initialization, growth, and maturation. Initialization involves random but guided generation of a candidate solution. After initialization, the algorithm successively goes through two loops, that is, growth and maturation. Computational tests performed on benchmark problems in the literature show that, when compared to competing metaheuristic algorithms, SM is more efficient and effective, producing better solutions within reasonable computation times.
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Electric power grids distribution generation system for optimal location and sizing — a case study investigation by various optimization algorithms

- Ali, Ahmed, Padmanaban, Sanjeevikumar, Twala, Bhekisipho, Marwala, Tshilidzi

Enhanced NSGA based on adaptive crossover rate and reference points

- Essiet, Ima O., Sun, Yanxia, Wang, Zenghui

Enhancing productivity through simulation and layout planning : a case study of a manufacturing company in South Africa

- Lehlake, Stephen Katlego, Muyengwa, Goodwell, Mawane, Yvonie N.

  • Authors: Lehlake, Stephen Katlego , Muyengwa, Goodwell , Mawane, Yvonie N.
  • Date: 2018
  • Subjects: Optimization , imulation , Modelling
  • Language: English
  • Type: Conference proceeding
  • Identifier: http://hdl.handle.net/10210/290739 , uj:31567 , Citation:
  • Description: Abstract: This paper aims to optimize a manufacturing process through creation of a simulation model that will be used to identify bottlenecks, restructure the layout and improve productivity. The paper also highlights the significance of process optimization in a manufacturing set up. Process optimizations strive to find the best solution for a process within the available constraints. Simulation is a collection of methodologies used to mimic the characteristics and behaviour of real system using computer software. Literature review was carried out to understand system dynamics and simulation. A case study was conducted at a manufacturing company. An Arena simulation model representing the process under study was developed and analysed. Various models were run and the results compared. The best model was developed that improved productivity through restructuring of the layout and minimization of the cycle times on the identified bottleneck stations. The simulation results showed that there was a vast difference on the amount of material input and the ATMs and Safes produced. The limitation of this study was that it only focused on the production of two products in the case studied company.
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Numerical optimization of small-scale thermo-acoustic refrigerators considering maximum cooling

- Tartibu, L. K.

  • Authors: Tartibu, L. K.
  • Date: 2018
  • Subjects: hermo-acoustic , Cooling , Optimization
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/280975 , uj:30220 , Citation: Tartibu, L.K. 2018. Numerical optimization of small-scale thermo-acoustic refrigerators considering maximum cooling.
  • Description: Abstract: The use of sound wave to remove heat could potentially contribute significantly to the development of a more affordable, sustainable search of an effective solution for electronics coolers. This work provides details of the implementation of a lexicographic optimization scheme in order to address the issue of dimensional optimization of a small-scale standing-wave thermo-acoustic refrigerator system. The cooling load has been considered as main criteria in the formulation and the measurement of the performance of the system. The dimensional parameters describing the heart of the device, namely the porous media (or the stack), where the heat pumping takes place are the variables to optimize. The problem has been formulated as a non-linear programming problem with discontinuous derivatives and implemented in the General Algebraic Modelling Systems (GAMS). The main contributions of the work are the detailed GAMS model and the clarity about the most preferred position and length of the stack considering prior knowledge of its porosity. This work reveals that shorter stack perform relatively better with respect to the cooling load performance. In addition, it appears that the position of the stack within the resonator tube is closely related to its length for maximum performance of the device.
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Optimization of the casting technology and sustainable manufacture of 100mm grinding balls for the mining Sector in Zimbabwe

- Nyemba, Wilson R., Moyo, Ranganai T., Mbohwa, Charles

  • Authors: Nyemba, Wilson R. , Moyo, Ranganai T. , Mbohwa, Charles
  • Date: 2018
  • Subjects: Mould , Optimization , Sustainable production
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/260433 , uj:27423 , Citation: Nyemba, W.R., Moyo, R.T. & Mbohwa, C. 2018. Optimization of the casting technology and sustainable manufacture of 100mm grinding balls for the mining Sector in Zimbabwe.
  • Description: Abstract: Excess waste is common in foundry die-casting processes due to a number of factors. These include sizes of runners and gates, heat and pressure that may result in expanded sizes of runners and oversized products that require more time for fettling after solidifying and removal from moulds. The gating system, runners and handling of the molten metal play critical roles in the efficiency and productivity of casting processes. This research was prompted and motivated by one of Zimbabwe’s largest foundries’ desire to reduce product costs brought on by drops in sales caused by more affordable imports. The research focused on the company’s major challenges such as excess waste and the long hours spent in manual fettling. This was done by optimizing the casting technology through the redesign of the gating systems for the sustainable manufacture of 100 mm grinding balls for the mining sector. The conventional casting approach, which is often unsystematic, was optimized using computational fluid dynamics and resizing of the gating system for the efficient and sustainable production of grinding media. Reductions in waste from 37% to 24% were anticipated based on the redesign, thus marginal reductions in the cost of grinding balls.
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Improved genetic algorithm based on PSO-inspired reference point placement

- Essiet, Ima O., Sun, Yanxia, Wang, Zenghui

  • Authors: Essiet, Ima O. , Sun, Yanxia , Wang, Zenghui
  • Date: 2019
  • Subjects: Non-dominated sorting genetic algorithm , Reference points , Optimization
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/395582 , uj:32807 , Citation: Essiet, I.O., Sun, Y. & Wang, Z. 2019. Improved genetic algorithm based on PSO-inspired reference point placement.
  • Description: Abstract: This paper investigates the performance of the Non-dominated Sorting Genetic Algorithm (NSGA) based on the placement of reference points in the objective function space. An improved version of NSGA is proposed and its performance is analysed for five and eight reference points respectively in the multi-objective function space. The reference points are arranged as two effective swarm topologies: wheel and Von Neumann topology, which have been widely used in Particle Swarm Optimization (PSO). Through the simulations, the wheel topology (called wheel reference point genetic algorithm (wRPGA)) based method achieves better performance than the one which is based on the Von Neumann topology. The wheel topology also achieves better performance with respect to IGD compared to KnEA, NSGAIII and MOEAD/D for 7 out of 15 CEC 2017 benchmark problems. Moreover, wRPGA gives a good approximation of the Pareto front for the 3-objective model representing the hypothetical microgrid.
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Performance analysis of cow dung as an eco-friendly binder and additive material for sustainable moulding and casting

- Patel, Manjunath G. C., Gupta, Kapil, Chate, Ganesh, Parappagoudar, Mahesh B., Sandeep, M. J., Daivagna, U. M.

  • Authors: Patel, Manjunath G. C. , Gupta, Kapil , Chate, Ganesh , Parappagoudar, Mahesh B. , Sandeep, M. J. , Daivagna, U. M.
  • Date: 2019
  • Subjects: Casting , Cow-dung , Optimization
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/404615 , uj:33939 , Citation: Patel, M.G.C. 2019. Performance analysis of cow dung as an eco-friendly binder and additive material for sustainable moulding and casting.
  • Description: Abstract: In the present work, an attempt is made to partially replace the high cost silica sand with sustainable eco-friendly material, namely cow-dung. Practical utility of cow dung as a binding and additive material in foundries has been tested in the present work. Taguchi method is used to plan and conduct nine experiments with three replicates each. Pareto analysis of variance study is done to understand the practical significance of moulding sand variables namely percent of cow dung, percent of clay, percent of water, and degree of ramming on sand mould properties. The conflicting multiple objective functions (maximize: mould hardness, and minimize: collapsibility and gas evolution) are optimized by utilizing data envelopment analysis ranking (DEAR) method. The optimal parameter levels i.e. 6% of clay, 4% of water, 5% of cow-dung and 4 numbers of ramming strokes are obtained by applying hybrid Taguchi- DEAR method. These parameters yielded the best moulding properties i.e. mould hardness 55, gas evolution 5.9 ml/gm , and collapsibility 470 g/cm2. Thereafter, Lovejoy coupling made of aluminium is cast in the sand mould prepared with cow-dung and without cow-dung. The sand mould is prepared with the optimum set of parameters and the casting produced in the mould has been tested for its quality characteristics. The mechanical properties, surface finish, and microstructure of the casting made in sand mould with cow-dung are found to be better than that obtained with sand mould without cow-dung. The present research work is found to be more useful in foundries for sustainable production of good quality casting.
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Intelligent optimization of Wire-EDM parameters for surface roughness and material removal rate while machining WC-Co composite

- Gupta, Kapil

Optimization of laser machining parameters and surface integrity analysis of the fabricated miniature gears

- Anghel, C., Gupta, K., Jen, T. C.

TOPSIS-Fuzzy-PSO Integrated Modelling and Computation of Wire-EDM Parameters for Productivity and Surface Quality while Machining Ni55.8Ti Shape Memory Alloy

- Gupta, Kapil

  • Authors: Gupta, Kapil
  • Date: 2020
  • Subjects: Computation , Optimization , PSO
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/411327 , uj:34561
  • Description: Abstract: Modelling and optimization of manufacturing processes for better quality engineered parts has always been a requirement. Numerous statistical and soft computing techniques have been used for this purpose. This paper reports on modelling and computation of Wire-EDM process parameters for optimum productivity and surface quality when machining Ni55.8Ti shape memory alloys using a TOPSIS-Fuzzy-PSO integrated hybrid technique. Ni55.8Ti is an important biomaterial and its appropriate machining at optimum set of parameters is essential to achieve high process productivity and to simultaneously maintain high product quality. Productivity in terms of material removal rate ‘MRR’ and surface quality in the form of maximum roughness ‘Rt’ and recast layer thickness ‘RCL’ have been considered. Four wire-EDM parameters namely servo voltage ‘SV’, pulse-on time ‘Pon’, pulse-off time ‘Poff’, and wire feed rate ‘WF’ have been varied at four levels each to machine Ni55.8Ti alloy based on Taguchi L16 robust design of experiment technique and the aforementioned conflicting responses have been measured corresponding to each experiment. To establish the relationship between wire-EDM parameters and the responses, all the response characteristics were converted into a single response of TOPSIS-fuzzy performance index (TFPi). PSO coupled with TOPSIS and Fuzzy logic has been employed for computation of optimum wire-EDM parameters for the best values of all responses considered. Analysis of variance (ANOVA) of TOPSIS-fuzzy performance index (TFPi) exhibited the effectiveness of the integrated hybrid technique. The optimum values of wire-EDM parameters obtained by hybrid technique are SV-50V; Pon-1µs; Poff-17 µs; WF-4 m/min for MRR-0.049 g/min, Rt- 11.45 µm, and RCL- 22.10 µm. Validation experiments conducted to confirm the reproducibility of the response characteristics predicted by hybrid technique.
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An Overview of TIG Welding of Ti6Al4V : Recent Developments

- Omoniyi, Peter O., Mahamood, Rasheedat M., Jen, Tien-Chien, Akinlabi, Esther T.

Intelligent machining of shape memory alloys

- Gupta, Kapil

  • Authors: Gupta, Kapil
  • Date: 2021
  • Subjects: Optimization , Shape memory alloy , TOPSIS-Fuzzy
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/482647 , uj:43774 , Citation: Gupta, K. 2021. Intelligent machining of shape memory alloys.
  • Description: Abstract: Shape memory alloys are important biomaterials but difficult-to-machine (DTM). Their machining needs to be done using intelligent techniques to obtain a better machinability. Hybrid optimization is one of such techniques which can perform modeling and optimization of machining parameters for the best values of machinability indicators. Wire electric discharge machining (WEDM) of shape memory alloy has been found as a prominent alternate to the conventional machining techniques; however it needs the assistance of intelligent techniques to machine such materials to obtain the optimum values of machinability indicators. In this paper, WEDM of shape memory alloy Ni55.8Ti was reported. WEDM was carried out by varying four process parameters i.e. servo voltage SV, pulse-on time Pon, pulse-off time Poff, and wire feed rate WF using Taguchi L16 robust design of experiment technique. A hybrid optimization technique TOPSIS-Fuzzy-PSO has been successfully used to optimize these parameters (SV-50V; Pon-1µs; Poff-17 µs; WF-4 m/min) for the best possible values of material removal rate (MRR) – 0.049 g/min, maximum roughness – 11.45 µm, and recast layer – 22.10 µm simultaneously.
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Modeling a Sustainable, Self-Energized Pine Dust Pyrolysis System With Staged Condensation for Optimal Recovery of Bio-Oil

- Gratitude Charis, Gwiranai Danha, Edison Muzenda, Trust Nhubu2

Modeling a Sustainable, Self-Energized Pine Dust Pyrolysis System With Staged Condensation for Optimal Recovery of Bio-Oil

- Charis, Gratitude, Danha, Gwiranai, Muzenda, Edison, Nhubu, Trust

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