International Journal of Engineering Research in Africa Vol. 26

Volume 26

doi: 10.4028/

Paper Title Page

Authors: Chetankumar M. Patel, Kartik D. Kothari, Ghanshyam D. Acharya
Abstract: Non-prismatic beams are extensively used for many engineering application. Due to varying section, deflection analysis becomes very complex. Loading condition also makes the whole theory complex. This paper shows analytical analysis for the deflection of trapezoidal sectorial section with uniformly perpendicular loading condition. The method illustrated is comparatively easy and can be applied for the similar other sections as well. Analytical method is validated using Finite Element Analysis using Creo Simulation which shows good amount of match with analytical result.
Authors: Taoheed O. Sadiq, Taiwo G. Fadara, Peter O. Aiyedun, Jamaliah Idris
Abstract: Numerical estimation of rolling load and torque often showed large discrepancies when compared with experimental values. This was attributed to difficulty in estimating the mean rolling temperature from the available data. This work is thus directed at obtaining a good estimate for the mean rolling temperature which can effectively be used for load and torque estimates. Hot flat rolling stimulation by use of the Bland and Ford’s cold rolling (HRBF) theory confirmed the reverse sandwich effect in selected carbon steels at low strain rates. In this work, the effect of pass reduction on rolling temperature distribution, yield stress and rolling load were studied for AISI Type 316 stainless steel (HSCSS316). For this new simulation, at low and high strain rates, results showed that the ratio of experimental to calculated rolling load and torque were higher at lower reduction than at higher reduction. These results confirmed excess load and torque in the hot rolling of HSCSS316 low reductions. The results obtained from Hot Rolling Bland and Ford’s Theory based on Root Mean Square rolling temperature were in good agreement with values obtained using Reverse Sandwich Model and the Reverse Sandwich- Hot Rolling Bland and Ford’s Program under the same rolling conditions.
Authors: Williams S. Ebhota, Akhil S. Karun, Freddie L. Inambao
Abstract: The study investigates the application of centrifugal casting process in the production of a complex shape component, Pelton turbine bucket. The bucket materials examined were functionally graded aluminium A356 alloy and A356-10%SiCp composite. A permanent mould for the casting of the bucket was designed with a Solidworks software and fabricated by the combination of CNC machining and welding. Oil hardening non-shrinking die steel (OHNS) was chosen for the mould material. The OHNS was heat treated and a hardness of 432 BHN was obtained. The mould was put into use, the buckets of A356 Alloy and A356-10%SiCp composite were cast, cut and machined into specimens. Some of the specimens were given T6 heat treatment and the specimens were prepared according to the designed investigations. The micrographs of A356-10%SiCp composite shows more concentration of SiCp particles at the inner periphery of the bucket. The maximum hardness of As-Cast A356 and A356-10%SiCp composite were 60 BRN and 95BRN respectively, recorded at the inner periphery of the bucket. And these values appreciated to 98BRN and 122BRN for A356 alloy and A356-10%SiCp composite respectively after heat treatment. The prediction curves of the ultimate tensile stress and yield tensile stress show the same trend as the hardness curves.
Authors: Williams S. Ebhota, Akhil S. Karun, Freddie L. Inambao
Abstract: This paper discusses the main Functionally Graded Materials (FGMs) and their bulk fabrication techniques, their development, principles and applications. The fabrication processes considered include powder metallurgy (PM), sintering, squeeze casting, infiltration process, compocasting, centrifugal casting, stir casting, material prototyping. The paper provides an overview of the FGM processing parameters including reinforcement particles size and volume %, temperature, pressure (for PM), and stirrer and mould rotational speeds (for stir and centrifugal casting processes respectively). The paper notes that the FGMs are widely used in the following sectors: automotive, medical, aerospace, aviation, nuclear energy, renewable energy, chemical, engineering, optics electronics etc.
Authors: Munmun Bhaumik, Kali Pada Maity
Abstract: Electro discharge machining (EDM) is most popular non-conventional electro-thermal machining process where electrical energy is used to generate a spark and thermal energy used to remove material from the workpiece. The primary goal of EDM is getting more material removal rate (MRR) with lower tool wear rate (TWR). For this investigation, machining parameters like peak current, pulse on time, gap voltage and duty cycle are considered as process parameter, and material removal rate (MRR) and tool wear rate (TWR) are considered as response. AISI 304 stainless steel and tungsten carbide are used as work material and tool material respectively. Taguchi L27 orthogonal array has been applied for designing the experiment. A hybrid optimization technique like desirability in combination with grey relational analysis (GRA) has been performed to get the optimum level of the control parameter for getting higher MRR and lower TWR. Analysis of variance (ANOVA) is performed for the statistical analysis. These results show that peak current is the most significant parameter for MRR and TWR. The optimal parameter setting for maximum MRR and minimum TWR has obtained by desirability coupled with Grey relational analysis.
Authors: Jefferson Stanley David, Jayaraman Viveckraj, Sivamani Seralathan, K. Varatharajan
Abstract: Solar energy is one of the alternatives to replace the use of conventional energy sources to heat water for domestic use. This paper focuses on the design and fabrication of a second generation indigenized FPC with locally available low cost material and compares its performance with existing costlier ETC solar water heating system. Readings of FPC and ETC are taken on different days at different time intervals having varied climatic conditions and humidity levels. Analysis of data showed that the rate of temperature rise in ETC is higher than FPC. The maximum temperature reached by these two solar water heating system varies from 2°C to 4°C. The difference between ETC and the indigenized FPC is the time taken to reach the peak temperature. This is due to a better conversion factor and a comparatively low thermal loss factor of ETC. Considering the energy saving involved, as the difference in temperature between FPC and ETC ranges from 0.10°C to 6.80°C, FPC is better suited to heat water for domestic uses given the climatic conditions prevailing in Coimbatore city, India.
Authors: Muhammad Syukri Imran, Azhaili Baharun, Siti Halipah Ibrahim, Wan Azlan bin Wan Zainal Abidin
Abstract: This study investigates cooling of water at night in Malaysian climate as renewable cooling medium source for radiant cooling purpose. An experiment with a 1.95 m2 steel roof rig structure was constructed and night cooling cycle was conducted during the hot season and cold season of the year. Regression model was developed to predict water temperature after the night cooling process and the corresponding water and roof ratio was established. An annual simulation of a low income home model retrofitted with radiant cooling system charged by night cooled water as cooling medium shows that 99% of the time the thermal condition could meet ISO 7730 category C PMV between-0.7 and + 0.7 . For an outdoor ASHRAE design day condition, the peak indoor operative temperature of 37oC could be lowered to about 30oC with the use of radiant cooling system. The calculated energy saving for the home model was 85% or about 15% of the conventional air system operating cost.
Authors: Nassim Djedoui, Abdelhafid Ounis, Mahdi Abdeddaim
Abstract: In this paper, a closed loop control approach for controlling the vibration of buildings under earthquake excitations is introduced. An active hybrid control combining base isolation and active tuned mass damper (AMD) installed on the lowest floor of a base-isolated frame building is investigated. The Active control force is controlled by the mean of a proportional–integral–derivative (PID) controller, incorporated with a negative feedback error closed loop. The difference between the base displacement and equilibrium position of the structure is used to evaluate the error and feed the PID controller. A simulation is carried out on a six degrees of freedom base-isolated frame structure using MATLAB. The performances of the proposed active hybrid control system are tested under El Centro, Northridge, and Loma Pietra earthquakes.Compared results with base-isolated structure and base-isolated structure equipped with a passive and active tuned mass damper (TMD)/ (ATMD) showed that the active hybrid control system is more efficient. A reduction of 70% in base displacement, velocity and 15% in base acceleration is obtained.
Authors: H.A. Bakir, F. Debbat, F.T. Bendimerad
Abstract: The combined system STBC-OFDM has considered an important association to integrate into actual and next wireless system. Such as the Wifi standard, WiMAX standard, the LTE fourth generation of mobile. Which combat the effect of multipath fading channel that limited the performance in wireless communications. In recent years, this association has been a large study to achieve a better performance of BER and designed for the different situation of the wireless channel from slow to fast fading channel, with various parameters of OFDM modulation and under different condition of STBC code. To contribute in this axis of research, we present a comparative study of the simulation result for STBC-OFDM. The first results are the comparison between three schemes of STBC (Alamouti code, Orthogonal STBC, Non-Orthogonal STBC) associated with OFDM. The second results are the comparison between three schemes when applied OFDM in different parameters and also when these codes used without OFDM modulation. The channel considered across simulation is Rayleigh fading channel that presented a real situation of the wireless environment, the Maximum Likelihood (ML) is used for detection the data that encoded in the first. The performance of three schemes is evaluated by BER (Bit Error Rate) versus the different values of SNR (Signal Noise Ratio).
Authors: Ighodaro Osarobo, Akaeze Chika
Abstract: It is common occurrence that the transportation of petroleum products via pipelines is susceptible to failure either naturally or intentionally. The paper is a diagnostic problem having continuous inputs of pattern recognition used in predicting pipeline failures. Our problem is to design a neural network that will recognize failure events in pipelines when fed with an input pattern denoting such a scenario. A neural network paradigm is selected, and encoding of input is done to obtain the input pattern. The selected model is simulated and trained to recognize the output pattern, which in our scenario after training, goes into operational mode.The neural network is fully implemented on a Pentium II MMX computer with a Borland C++ builder.

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