International Journal of Engineering Research in Africa Vol. 13

Abstract: The petroleum refinery wastewater biological treatment is widely investigated because of the potential complete mineralization and environmental aspect. In this study, petroleum refinery wastewater was treated in an extended aeration activated sludge (EAAS) reactor A, operated in parallel with EAAS reactor B as a control, fed with municipal wastewater. The chemical oxygen demand (COD) organic loading rate (OLR) of the refinery wastewater in reactor B was approximately 0.057 kg COD/m³·d compared to reactor A of 0.004 kg COD/m³·d throughout the study period. The flowrate for both reactors was maintained at 21.4 L/day. Food to microorganism (F/M) ratio, COD, mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids (MLVSS) were monitored throughout the study period. The result indicated high removal efficiency of organic matter of approximately 87% as COD with 2582 mg/L of the petroleum refinery wastewater as influent and 140 mg/L as effluent.

Abstract: The unrestrained growth in urbanization and motorization generally contributes to an urban land use and transport system that is socially, economically, and environmentally unsustainable. Urban mobility systems are much diversified in developing countries taking into account their components in terms of transport modes and the development path linked to the urban growth. This paper uses Cotonou as a case study, which is the largest urban and economic city of Benin. The paper first reviews literatures on sustainable transport systems to comprehend the concept of sustainable development and transport. Based on the municipal development plan (MDP) adopted by the local authorities, the paper then evaluates the existing transport policies, projects and infrastructure system, to determine if the current paradigm is moving toward or away from sustainable transport. Furthermore, the principles for sustainable urban transport are developed to see what significance municipal transport policies have given to urban transport from a sustainable transport point of view. Finally some strategies are suggested, adoption of which may lead to a sustainable urban development and transport system in the city of Cotonou.Key words: Sustainable development; urbanization; Bus Rapid Transit; socio-economic; land use and urban transport system.

Abstract: The present study investigates the thermal diffusion and radiation effects on magneto hydro dynamic mixed convection flow of a micro polar fluid past an infinite, steadily moving porous plate with variable suction and constant viscosity. The equations of continuity, linear momentum, angular momentum, energy and diffusion, which govern the flow field, are solved by using a regular perturbation method. The behavior of the velocity, micro rotation, temperature, concentration, skin-friction, Nusselt number, and Sherwood number has been discussed for variations in the physical parameters with the help of the graphs.

Abstract: In allusion to phenomenon of large instability of underground goaf, research is carried on prediction of instability and mechanism of multi-factor comprehensive action. Firstly, according to large number of examples of instability disaster in mines at home and abroad, influence factors of goaf stability was analyzed, including characteristics of surrounding rock, conditions of engineering geology, engineering properties, structure parameters of goaf and other artificial mining and time etc; then, using BP neural network to establish the comprehensive function matrix RSE, and putting forward a prediction index F_i, this index can be real-time tracking on the actual change conditions of surrounding rock scene in mining goaf, showing the comprehensive action results of each factor on steady state of underground goaf engineering system; finally, on the basis of 36 samples, the stable value and interval value of the corresponding multi-factor comprehensive action index F_i can be obtained after calculation by using comprehensive function matrix RSE. An actual example showed that, value of multi-factor comprehensive action index F_i was-0.8159 in goaf of an iron mine, which was in instability state.

Abstract: Many Small and medium scale enterprises (SMEs), because of the limited scope and size of their operations consider investment in proprietary Enterprise Systems unattractive. Meanwhile In-house development approach has been identified as a way deepening the adoption of these productivity enhancement systems among SMEs in developing economies. This paper presents a framework for developing Manufacturing Resources Planning software adaptable for SMEs in Nigeria and other developing economies. After the critical study and analysis of manufacturing systems, algorithms were developed for generating the material requirement plans for four different lot-sizing techniques. Subsystems for determining Labour and machine capacity requirements and costs, subsystems for material and running costs were integrated into the MRP algorithms. User friendly software of the resulting system was developed using visual basic. The system components were tested using a small-scale process and a middle-scale process to ensure proper functionality. The software which comes with various graphical reporting tools like tables and bar charts was shown to be flexible and accurate, suitable for small and medium enterprises.Keyword: Enterprise Systems, inventory, Material Requirement Planning, Resources planning

Abstract: The dynamic behavior assessment of material is very important before selecting the material for structural applications. In the modern world, Modified Hopkinson pressure bar apparatus is being widely used to investigate the dynamic behavior of engineering materials under compressive and tensile loading. Materials like ceramics, rocks, metals, concrete and soft material are being tested. The cost associated with the dynamic loading pressure bar apparatus are also low and can be easily built. For accurate measurement of material properties we need to understand the basic concepts associated with dynamic loading. With the advancement in computational capabilities, the dynamic load testing of materials is also performed in available commercial software's. In the current work, the basic concepts and components associated with dynamic compressive loading system are discussed and a test case studies are also selected for analyzing material specimen behavior during testing. For simulation of dynamic compressive loading ANSYS LS-DYNA software is used and the output of the simulation results is analyzed. The effects of changing the diameter of material specimen, and hollow bars on stress and strain values in the bar and setup are also discussed.

Abstract: The conventional models of car-following are too idealistic since they did consider that vehicles travel in middle of the lane. In order to depict the real car-following behaviors better, in this paper we present a new car-following model by introducing the minimum safe distance and proposing the concepts of maximum escape speed (MES) after taking into account the leading vehicle position in the road and the impact of the centerline separation between the leading vehicle and the following vehicle on the car-following behavior, extending the car-following model into two-dimensional model. Finally, the numerical simulation analysis was made using the built model by the Matlab simulation platform. It is found that required minimum safety distance of the presented model is less than the previous models required. Meanwhile, the model can describe some macroscopic phenomena in the actual traffic flow and can improve effectively the road capacity and smooth.

Abstract: The chemical quality of several water samples comprised groundwater from various aquifers and water dam, in Biskra area of South Algeria was investigated. Water samples were collected to monitor water chemistry of major ions and minor ions comprising inorganic pollutants such as fluoride, phosphates, nitrates and trace element as cadmium. The results showed a high salinity associated with an excessive hardness. The concentrations of many inorganic compounds are above the permissible limits for standard drinking water in almost water sources. The pollution is mainly attributed to a geological origin and an extensive use of fertilizers. Some water need adequate treatment to overcome inorganic pollution problem for drinking purpose. The adsorption of fluoride, nitrate, phosphate and cadmium ions onto Algerian bentonitic clay was studied in batch system. The results showed that sulphuric acid activated bentonite was more efficient than raw clay for fluoride, nitrate and phosphate removal. The results also revealed that cadmium adsorption was better with raw bentonite. The equilibrium data were confirmed using Langmuir isotherm model.

Abstract: This paper proposes a multi-objective fuzzy linear programming (MFLP) procedure for maximizing the effects of preventive reactive power control actions to overcome any emergency condition when they occurred. The proposed procedure is very significant and seeks to eliminate violation constraints and give an optimal reactive power reserve for multi-operating conditions. The proposed multi-objective functions are: minimizing the real transmission losses, maximizing the reactive power reserve at certain generator and maximizing the reactive power reserve at all generation systems and/or switchable devices. The proposed MFLP is applied to 5-bus test system and the West Delta region system as a part of the Egyptian Unified network. The numerical results show that the proposed MFLP technique achieves a minimum real power loss with maximal reactive reserve for power systems for different operating conditions.

Abstract: Micro, Small and Medium Enterprises (MSMEs) make a significant contribution, by reducing unemployment in India. They need to operate efficiently and productively in order to maximize their contribution to nation, as well as national economies. MSMEs play a significant role in the economic growth of the country owing to production, exports and employment. They contributes 8% to the countrys GDP, 45 % to manufactures output and 40% to the countrys exports. It provides employment to 60 million people. The aggressive competition situation arising out of globalization and liberalization is forcing the organization across the globe to realize that their survival is not feasible in the absence of technological innovation. Technology innovation reflect a critical way in which organization respond to either technological or market challenges. Therefore, the importance of technology innovation in organizations competitiveness is an undeniable fact. The literature reveals that most significant determinants of technology innovation associated with MSMEs are technological collaboration and monetary management. These determinants are relatively significant in improving the manufacturing performance of MSMEs.