scholarly works
Permanent URI for this collectionhttps://repository.ui.edu.ng/handle/123456789/473
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Item Comparison of compromise constraint bi-objective LP method and three traditional weighted criteria methods(Department of Industrial and Production Engineering, University of Ibadan, 2020) Adeyeye, A. D.; Arise, O. T.; Charles-Owaba, O. E.Item Application of mathematical programming approach to welding flux development(Nigerian Metallurgical Society, 2011-05) Adeyeye, A. D.Item A biobjective production planning model and application of three LP procedures(Nigerian Metallurgical Society, 1999) Adeyeye, A. D.; Charles-Owaba, O. E.A biobjective model is proposed for production planning in a multi-stage, multi-facility production system. The decision situation considered was a case where the Decision Maker (DM) wants to determine the quantities of materials to be fed into each production facility at each stage of production that gives maximal realization of his objectives. A numerical example is solved using three Linear Programming procedures. The methods used are: Compromise Constraint Biobjective LP (CCBLP), Linear Combination of the Objective Functions (LCOF) and Goal Programming (GP). The behaviour of the CCBLP model shows that it is superior to LCOF and non-preemptive GP in terms of its sensitivity to relaxations in the objectives. It also supports the result of an earlier research that the CCBLP gives the real compromise solution.Item Effect of some variables on the carburization of a locally produced steel(Nigerian Metallurgical Society, 1987) Adepoju, O. T; Balogun, S. A.; Adeyeye, A. D.The effects of carburizing time, temperature and percentage energizer on the case-depth and hardness of a steel ST37-2 have been studied. For carburizing medium consisting of hardwood charcoal and coke and various amount of sodium carbonate as energizer, increasing carburizing time and temperature increased both the depth and hardness of the case. Increasing both the amount of energizer and carburizing time lowered the activation energy for the carburization process. The average hardness of the carburized layer decreased with tempering. Two processes are found to be operative during carburizing; one which is strongly activation energy dependent and the other which is mildly dependent on activation energy.Item A mathematical modelling of the intensity of contaminants (C02) on occupancy level of a spacein continuous use(Inderscience Enterprises Limited, 2008) Oke, S. A; Oyedokun, O. I.; Akanbi, O. G.; Adeyeye, A. D.This study investigates the Indoor Air Quality (IAQ) of a room apartment and focused on the number of occupants that a space or an apartment can accommodate as a result of increase in the concentration level of the CO2 contaminant present within the space. The law of mass action was applied to generate a relation between the concentration of CO2 produced and the concentration of the reactants (i.e., O2 and CO). A decay equation was also used to relate the variation in the number of occupants with the level of the concentration of CO2 within the space only at steady state conditions.Item A Study of Processing Parameters on the Carburization of C2R Steels(Scientific Research Publishing, 2009) Atanda, P. O.; Olorunnuwo, O. E; Umoru, L. E.; Adeyeye, A. D.; Adeyeye, A. D.This study reports an investigation of the effect of carburizing variables - temperature, time and percentage of energizer on the case properties of C2R steel obtained from HMT Ltd. India. A carburizer consisting of hardwood charcoal and coke respectively in the ratio of 2:1 was used for the research with sodium carbonate as the energizer. The carburizing box was filled with 20mm thick carburizer compound prior to fixing the steel samples in place. The specimens were carburized using different percentages of energizers (10, 20 and 30%) at different temperatures (820, 860, 900 and 940°C) for different times (from one to five hours). All the specimens were quenched from carburizing temperature, ground to polished surfaces and then etched for ten minutes in 25% Nital. The case depth was measured using the calibrated ocular of an inverted metallurgical microscope fixed at 100 x magnification. The hardness values of the C2R steel cases were measured with a micro hardness tester that uses diamond pyramid indenter. The results of the study showed that the average hardness of the C2R steel cases increased with temperature for any given carburizing time and temperature. For a given percentage energizer and temperature, the case depths and hardness increased with time. Increase in the percentage energizer however decreased the activation energy required for diffusion to occur exponentially.Item What and how about competitive benchmarking(ABM, ABC and ABPol, 2011) Adeyeye, A. D.Most of the domestic industries In Nigeria lag behind their foreign competitors when it comes to cost and quality. People turn to the low price and often higher quality of imported goods. This paper suggests that benchmarking could be used to match and even exceed the competition. Based on the experience of companies in the industrialized world that have successfully used benchmarking to overcome adversity and have emerged stronger, the paper suggests that the same success could be achieved by our domestic industries. The description of the benchmarking process, the guidelines and framework for its application and some of the implementation problems are discussedItem Weld-metal property optimization from flux ingredients through mixture experiments and mathematicla programmimng approach(ABM, ABC and ABPol, 2009) Adeyeye, A. D.; Oyawale, F. A.This paper presents a new methodology for weld-metal properties optimization from welding flux ingredients. The methodology integrates statistical design of mixture experiment with mathematical programming optimization technique. The mixture experiment is responsible for the modeling of the weld-metal properties as a function of welding flux levels while mathematical programming optimizes the model. Data and confirmed models from the literature were used to perform optimization on the responses. The maximum values possible with the prevailing conditions for acicular ferrite, charpy impact toughness and silicon transfer are 51.2%, 29 J and 0.231% respectively while the minimum oxygen content possible is 249 ppm. The new methodology is able to eliminate the limitations associated with the traditional experimental optimization methodology for flux formulation.Item Optimisation of weld-metal chemical composition from welding flux ingredients: A non-pre-emptive goal programming approach(Maejo University, San Sai, Chiang Mai, 50290 Thailand., 2010) Adeyeye, A. D.; Oyawale, F. A.A non-pre-emptive goal programming (NGP) model for weld-metal chemical composition optimization from welding-flux ingredients is proposed. The proposed model, which is the first multi-objective mathematical programming approach to welding-flux formulation, provides increased flexibility to the welding-flux formulator in several ways: (1) several conflicting objectives can be simultaneously considered, (2) the best compromise for welding-flux formulation can be achieved with minimal expenditure of resources and experimental efforts, (3) the welding-flux designer can explore various trade-off options, and (4) the lead time and cost of developing welding consumables can be drastically reduced. This paper has extended the work of Kanjilal and co-investigators by coupling it with the NGP optimisation technique so as to prescribe the welding-flux ingredient levels that will achieve optimum performance for the flux at minimum experimental efforts and cost. The feasibility and suitability of the model is illustrated with data from the literature.Item Multi-objective methods for welding flux performance optimization(Faculty of Natural Science and Engineering, Ljubljana, Velenje Coal Mine and Institute for Mining, Geotechnology and Environment (IRGO), Ljubljana, 2010) Adeyeye, A. D.; Oyawale, F. A.The traditional welding flux development is by lengthy and costly trial and error experiments and the optimum welding flux formulation is not guaranteed. This paper presents discussions on promising multi-objective decision making (MODM) methods that can mitigate the limitations of the traditional approach to welding flux design. The methods are weighted-sum scalarization (WSS), desirability indices, goal programming and compromise programming. The steps a welding flux designer (WFD) may follow to determine the best compromise welding flux, welding flux design situations where each may be useful and tradeoff explorations were mentioned. No attempt was made to determine the relative merits of the approaches because the usefulness of each depends on the welding flux design situation. The descriptions only serve as a guide for the WFD to decide which method best suits his needs.