International Journal of Engineering Research in Africa Vol. 35

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Authors: Sifeddine Abderrahmani, Toufik Maalem, Djamal Hamadi
Abstract: In this paper, we present a comparative study of the transverse shear effect on the plate bending. The element used is a rectangular finite element called SBRPK (Strain Based Rectangular Plate-Kirchhoff Theory-), it used for the numerical analysis of thin plate bending, and it based on the strain approach. This element has four nodes and three degrees of freedom per node (w, θx, θy). Through the numerical applications with different loading cases and boundary conditions; the numerical results obtained are in close agreement with the analytical solution.
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Authors: David O. Olukanni, Ola O. Oresanya
Abstract: One of the challenges of Lagos State is efficient and cost-effective solid waste management. This paper focuses on progress made in waste management operations in the State. An assessment to know how waste generation, collection, transportation and disposal have put demands on state resources, and its physical infrastructure was carried out. The state generates about 12,000 metric tons of waste daily (0.72kg/person/day). Due to limited budgetary allocation, the state government instituted the Lagos State Waste Management Authority (LAWMA) to perform supervisory roles and charged with the implementation, advocacy, monitoring and enforcement of waste management policies. As part of its roles, the agency enlisted Private Service Providers (PSP) for the purpose of appropriate billing of waste services. LAWMA centrally collects revenue and remits agreed portion of 60% of waste charges to individual PSP accounts in accordance to estimated waste collected. The state is focused on resource recovery programs such as composting, land filling and pelletizing of plastics and nylons. The implications (environmental, economic, social and financial) for managing solid waste gives credence to the renewal campaign for resource conservation and environmental sustainability. Thus, the 4 Rs of waste management – Reduction, Reuse, Recovery and Recycling are being demonstrated through establishment of compost production plant, championing of Waste-To-Wealth Initiatives and Renewable Energy (RE).
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Authors: Abderrahim El Attar, Mostafa El Hachloufi, Zine El Abidine Guennoun
Abstract: In this paper we present an approach to minimize the actuarial risk for the optimal choice of a form of reinsurance, and this is intended to be through a choice of treated parameters that minimize the risk using the Conditional Tail Expectation and the Conditional Tail Variance risk measures. The minimization procedure is based on the Augmented Lagrangian and a genetic algorithm with technical benefit as a constraint. This approach can be seen as a decision support tool that can be used by managers to minimize the actuarial risk in the insurance company.
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Authors: Youssef Saada, E.M. Yahyaoui, Nadia Ouadoudi, Rachid Skouri, Abdelmajid Daya
Abstract: In this work, we propose two mathematical simulation methods to evaluate the results of conditional preventive maintenance strategies based on controls and inspections with optimal performance. In order to have an optimal availability of the equipment in question, the evaluation of the maintenance strategies associated with the controls will be treated by the method of the fault trees based on the decision binary diagram with the calculation engine ALBIZIA. The maintenance performance associated with inspections will be determined by Petri networks coupled with the Monte Carlo method.
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Authors: Ogunboyo Patrick Taiwo, Remy Tiako, I. E. Davidson
Abstract: With ever increasing use of semiconductor devices and information technology (ICT) equipment in the industry, homes and offices, power quality is gaining attention to both industry and the electric utility. Power voltage quality cause huge economic losses to businesses all over the world. It is estimated to cost industry and commerce about €100 billion per annum in European Union, since voltage quality problem is one of the major power quality disturbances. This paper presents an investigative a study of the 11/0.4 kV, low voltage electrical distribution network and analyzes voltage unbalance. It recommends an effective method of improving the voltage profile and reducing the voltage unbalance to acceptable standard. The network was modelled using distribution network standard parameters for low voltage distribution network using MATLAB/Simulink sim power system tool box. The simulation results show that the percentage voltage unbalance, correct voltage profile and minimum voltage drop of 0.5 km distribution feeder line is of standard acceptable statutory limit, hence the distribution line operates at optimum performance. However, it is also established that the voltage profile for distribution network feeder lengths of 0.8 km to 5 km for balanced and unbalanced distribution lines from the beginning to the customer terminal of the distribution lengths are less than the acceptable allowable limit of – 5 %, of the nominal voltage value, hence voltages are inadmissible for customers use. Moreso, the percentage voltage unbalance, voltage profile and voltage drop on 0.8 km to 5 km distribution feeder line are all less than standard acceptable statutory limit, hence the distribution line operates below optimum performance. It was established that mitigating these problems require the electricity distribution company to install an effective voltage boosting devices along the network lengths in order provide admissible, permissible and normalize end users standard acceptable voltage.
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Authors: Vasyl Lozynskyi, Pavlo Saik, Mykhailo Petlovanyi, Kateryna Sai, Yevhenii Malanchuk
Abstract: In this paper, the geological faults in the zone of stable geodynamic and tectonic activity are studied. The purpose of the analytical research is to establish regularities of rock pressure in the hanging and foot walls of the geological fault and its influence on the state-deformed state of the rock massif. Comprehensive methodology that included analytical calculation will be implemented in the work. Taking into account the complexity of determining the stress-deformed state of the rocks, evaluation method of tension is adopted. Results of previously conducted computer modeling results are compared with analytic data. Conclusions regarding the implementation of the offered method are made on the basis of undertaken investigations. The obtained results with sufficient accuracy in practical application will allow consume coal reserves in the faulting zones.
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Authors: Taoheed O. Sadiq, Sulaiman A. Olawore, Jamaliah Idris
Abstract: Machining of titanium alloys poses a serious challenge for the industry, due to its tendency to work harden during the machining process, high cutting temperatures, high cutting pressures, chatter, and its reactivity with tool materials over 500°C. In conjunction with its low thermal conductivity and low modulus of elasticity, these factors impede the machinability of titanium. This work presents an overview on machining the Titanium Alloy by considering the energy involved in the manufacturing processes in order to have a low carbon manufacturing requirements by evaluating carbon emission in the manufacturing process plan.
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Authors: Remigius Chidiebere Diovu, John Terhile Agee
Abstract: In a secured smart grid AMI environment, congestion management during data aggregation with security encryption for privacy preservation is a challenging issue. By introducing data communication network schemes into the Advanced Metering Infrastructure (AMI), network traffic congestion and service rates can be improved while preserving user’s privacy from the grid operator’s end. In this paper, a resilient architecture called Ring Triangulation Communication Architecture (RTCA) for data aggregation and user privacy protection is proposed. To preserve privacy as well as reducing traffic congestion in the architecture, DMF homomorphic encryption algorithms were formulated for local concentrators while using a global concentrator to check for anomalies in the AMI server clusters. With TCP/IP protocol and IEEE 802.11 MAC/PHY on the network, TCP message flooding was contextualized for congestion scenario. Stochastic TCP congestion management schemes with wired equivalent privacy (WEP) and the Data Minimizing Function (DMF) scheme were compared. Our proposed architecture significantly reduced transmission congestion and cryptographic overheads incurred during message aggregation. The results of the performance of the DMF Homomorphic encryption scheme incorporated into our proposed architecture for the SG AMI were discussed. These include service rate and other QoS metrics which are negatively affected by a congestive network condition.Keywords: Advanced Metering Infrastructure (AMI), Data Minimizing Function (DMF), Ring Triangulation Communication Architecture (RTCA), Data Aggregation, Smart Grid (SG), Smart Meter (SM).
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Authors: Vincent Aizebeoje Balogun, Edem Friday Isuamfon, B. Otanocha Omonigho
Abstract: The energy consumption and machinability index of metallic alloys are very important in determining the economic and environmental value of manufacturing process. Various machinability problems with Nitronic 33 steel alloy have been reported in literature. These problems have been attributed to the work hardening of the material during machining operation and hence greatly influences and contributes to the green house gas emission. In this work, the chip and burr formation during the machining of Nitronic 33 steel alloy was investigated in other to optimize the cutting parameters and provide a knowledge base for machinists when machining austenitic stainless steels. The result shows that although continuous chips were formed throughout the machining tests, an evidence of continuous chip with built-up edges was also observed. This phenomenon tends to initiate the formation of discontinuous chips especially at high pressure coolant flow of 7 and 9.7 MPa. It is concluded that conventional cutting environment at 90 m/min cutting velocity is the optimum process parameter most suitable for machining Nitronic 33 steel alloy. The research outcome will address some of the problems encountered during high speed machining of Nitronic 33 steel alloy and the general understanding of the machinability of this alloy.
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Authors: Abdulwahab Giwa, Abel Adekanmi Adeyi, Victoria Abosede Adeyi
Abstract: The combination of chemical reaction and distillation, which is analogous to inserting a chemical reactor into a distillation column, is a phenomenon that can be accomplished using a single piece of equipment known as a reactive distillation column, and the phenomenon is, thereby, referred to as reactive distillation process. Because of this combination, a lot of benefits such as improving reaction conversion, suppressing side reactions and utilizing heat of reaction for mass transfer operation can be achieved. However, this combination has made the control of this process a little bit challenging because of some disturbances that normally affect its smooth running. Therefore, cascade control method, being a type that can be used to handle any disturbance before it affects the main process, is applied in this work to carry out the control of a biodiesel reactive distillation process using proportional-integral-derivative (PID) control algorithm. The responses of the process towards the applications of step changes to the input variable (reboiler duty) of the process revealed that it was stable because it could attain steady states. Also, the closed-loop simulations showed that cascade PID controller was better for the control of the process than the conventional PID controller owing to the fact that the responses of the cascade PID control system, upon the application of step changes to the set-point value of the controlled variable, were found to get to the desired setpoint faster and in a better way than those of the conventional PID control system. Moreover, the superiority of the cascade PID controller over the conventional one was demonstrated by the estimation of the integral absolute error (IAE) and integral squared error (ISE) of the cascade control system, which were obtained to be less than those of the conventional PID control system.
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