Modern Mechanical Engineering

Journal Information
ISSN / EISSN : 2164-0165 / 2164-0181
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 165
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Latest articles in this journal

Samson K. Fasogbon, Vincent N. Ugwah, Olaleye M. Amoo, Patrick Ajaero, Ogagaoghene D. Emma-Egoro
Modern Mechanical Engineering, Volume 12, pp 63-73;

Internal combustion engines with application in automobiles and other relevant industries constitute significant environmental pollution via the release of toxic exhaust gasses like carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), and nitrogen oxide (NOx). Engine researchers and manufacturers are challenged to develop external and internal measures to ensure environmentally friendly solutions to accommodate and conform to the growing list of emission standards. Therefore, this work presents an experimental investigation of the NOx emission profile of a diesel engine that is fuelled and fitted with waste frying oil-based biodiesel and catalytic converter. Using a single-cylinder, four-stroke air-cooled CI engine at a constant speed of 1900 rpm and different loadings of 25%, 50%, 75%, and 100%; fitted with a catalytic converter at the exhaust outlet of the engine and linked to a dynamometer and a gas analyser, an experiment was conducted at biodiesel/diesel volume blends of B0 (0/10), B5 (5/95), B20 (20/80), B30 (30/70), B70 (70/30), B100 (100/0); and 30% concentration (v/v), 0.5 litre/hr flow rate of aqueous urea from the catalytic converter. The results show an increasing NOx emission as the biodiesel component increased in the blend. The catalytic converter showed a downward NOx reduction with a significant 68% reduction in efficiency at high exhaust gas temperatures. It is concluded that the combined utilisation of waste frying oil-based biodiesel and the catalytic converter yields substantial NOx emission reduction.
Joseph Voufo, Zakari Yaou, Florent Biyeme, Rolland Djomi, Richard Dadji Metangmo, Théodore Tchotang
Modern Mechanical Engineering, Volume 12, pp 1-26;

The present work deals with reducing greenhouse gas emissions through improving the life span of wooden power electric poles of Eucalyptus saligna. Indeed, in Sub-Saharan African countries, Cameroon in particular, most of the power line networks are made of wooden supports and according to the Cameroon energy distribution company, wooden poles represent 32% of the causes of death linked to the state of the network. The company’s 2019 annual report indicates that 40,000 wooden poles were in critical condition and should be replaced. A significant number of mechanical failures affecting these supports have been observed. For example, on the HVA/LV power line “D17 Nko- abang” in Yaoundé in Cameroon, less than three years old, 10 (ten) cases of poles falling and/or breaking, due to their mechanical loading, were observed over a period of fewer than nine months, causing an average service stoppage for more than 11 hours and affecting an average of 3280 customers. These incidents lead to questions about how the supports are dimensioned and what load capacities they are designed to support. The aim of this work is, therefore, to suggest a method of dimensioning wooden poles hence reducing green- house gas emissions due to the deforestation by reducing the number of woo- den poles at risk to be replaced on Cameroon’s electricity distribution network. And more specifically, to reduce the number of mechanical failures affecting the wooden supports observed by analyzing the current wooden supports with their loads and to make proposals for improving the actual dimensioning me- thods. From the study carried out, it appears that 449 out of 845 supports, i.e., 53% needed to be replaced or monitored because they support the nominal forces ranging from 85% to 150% of their admissible limit and proposals have been made to improve their dimensioning.
Casanova-Del-Angel Francisco, Córdova-Castillo Alejandra
Modern Mechanical Engineering, Volume 12, pp 27-44;

This document uses previous results (which we call the first stage), for the development of a computer model based on finite elements under the FEAP programmer, to carry out a structural analysis of a pipeline. For this purpose, we used environmental variables that we believe influence the failure of buried pipelines such as the internal pressure of fluid, the type of support used, the temperature at which the pipelines work, the type of soil and the stiffness of the soil acting on it. Once the model was finalized, analyses were made with each of the variables separately and combined to observe the behavior of the pipeline, finding the most unfavorable case that indicates the main causes that led to its failure.
Gagnon Koffi Apedanou, Kokou N’Wuitcha, Yendoubé Lare, Kossi Napo
Modern Mechanical Engineering, Volume 12, pp 45-61;

Mixed convection of heat and mass transfer in an isosceles trapezoidal cavity has been studied numerically. Constant heat flux is imposed through four outlets and the grid is insulated. The inclined walls are maintained in natural convection while the lower horizontal wall is adiabatic. These conditions reflect the air draft zone of the ASUTO charcoal stove. The governing two-di- mensional flow equations have been solved by using the finite difference method and Thomas’s algorithm. The investigations are conducted for different values of Richardson (Ri), Reynolds number (Re) and inclination angles of sidewalls. The results are presented in terms of streamlines, isotherms, moisture contours. It was found that for Reynolds number (Re) equal to 100, the flow pattern is strongly dependent on the inclination angle and Richardson number. Thus, for high Richardson number (Ri) values (10, 100), the dominance of natural convection over the flow structure decreases with the decreasing of the inclination angle of sidewalls of the cavity. For Ri = 1, an optimum air draft corresponds to an inclination angle in the vicinity of 22° while for Ri = 10 or 100 (in dominance of natural convection), the optimum inclination angle for air draft is in the vicinity of 15°.
Maurice Vanlie Kontchou, Théophile Emakoua, Achille Njomoue Pandong
Modern Mechanical Engineering, Volume 12, pp 74-82;

In the design of the CAT 3408 engine, the Low Temperature (BT) circuits used to cool the engine lubricating oil and the charge air and the High Temperature (HT) circuits for cooling the cylinder liners, cylinder heads and body of turbofans are mainly used to cool the engine, so that it works properly. This work, based on the analysis carried out, to determine the lubrication compliance of the Yacco VX 100 - SAE 15 W-40 oil and that of the Camwater water used in the engine of the Boat Yang 1 by carrying out a series of conventional tests such as that: the density, the viscosity, the viscosity index, the flash point, the density, the sulphate center content, the water content, the total acidity index (TAN), total basic number (TBN) and pour point for the oil case and pH, hardness, sodium chloride content [NaCl], sodium sulphate content [NaSO4] for the water case which will be compared to the specified requirements to determine whether compliance is achieved for each of these characteristics. The results of the oil and water samples taken from the engine after use show that the used oil gives a specific gravity of 0.8822, a viscosity (at 40°C) of 92.29 mm2/s, a viscosity (at 100°C) of 13.99 mm2/s, a viscosity index (VI) of 155.39, a pour point -21°C, a Flash Point (VO) 215°C, a Sulfated ash content of 18%, a density 881.5 kg/m3, a total basic number (TBN) of 12.60 mgKOH/g, a Total Acid Index (TAN) of 3.096 mgKOH/g, a Water Content of 1.8 % and the water used gives a pH of 6.00, a hardness of 3.2 french degrees, a sodium chloride content [NaCl] of 0.468 mg/L, and a calcium sulphate content [CaSO4] of 2.38345 mg/L. the results of the water content and content of sulfated centers justify the thermal overload and power losses in the marine diesel engine CAT 3408 of the boat Yang 1 because of their values which are not in conformity with the standards.
Ouliang Jin
Modern Mechanical Engineering, Volume 11, pp 53-72;

The microstructure of bacterial is an important reference to design underwater swimmers. Applying Buckingham Pi Theorem is a possible method to build a scaled model based on a theoretical flagellum designed with traditional Resistive Force Theory. By making a scaled model, the forward velocity could be obtained to verify the application feasibility of Buckingham Pi Theorem in such designs. The optimal value of the model’s pitch angle can be calculated with the traditional RFT as well as the forward velocity. Comparing the experimental results with the results of theoretical calculations, it is found that the experimental and calculated results are consistent, which means Buckingham Pi Theorem works well in such design of underwater swimmer.
Nurudeen A. Raji, Kasali A. Adedeji, Elkanah O. Oyetunji, Ayodeji D. Agbelusi
Modern Mechanical Engineering, Volume 11, pp 1-11;

The design of bevel gear for use in the development of revolving rostrum is presented. The pinion gear is designed to rotate at 1400 rpm for the output gear of 23 rpm. A suitable gearmotor was selected for the design based on the bevel gear design analysis. The motion is transmitted to the rostrum via a shaft keyed to it with a gib-head key and assembled on the rostrum with a spline connector. The analysis of the bevel mesh shows that maximum deformation of about 26.552 mm occurs in the pinion due to the loading the pinion tooth. The deformation of the tooth is observed to affect considerable the performance of the system. The transmission efficiency of the mechanism was obtained as 86% though effective for the operation of the system but could be improved by a more careful material selection for the bevel gear mesh.
Wissam M. Alobaidi, Eric Sandgren
Modern Mechanical Engineering, Volume 11, pp 27-51;

A creative and/or innovative computer aided design environment is developed around the concept of an evolutionary optimization algorithm. Designs are generated within a set of prescribed design frameworks using a problem specific encoding and modified through operations including recombination, crossover and mutation. Evaluation of all candidate designs is performed by a user through a graphical user interface. A set of problems involving the creation of graphic images is presented. The examples include the generation of a set of two dimensional polygonal shapes, fractal images, path generation from a multi-degree freedom mechanical planar linkage and a mathematically prescribed pattern generation from a graphic design application utilized in quilting. Post design evaluation of the user input to the process provides insight into the individuals design strategy as well as determination of common user attributes in the creative design process.
Olusegun A. Adefuye, Nurudeen A. Raji, Rafiu O. Kuku, Timothy Oyetade, Ridwan O. Ola-Gbadamosi
Modern Mechanical Engineering, Volume 11, pp 13-26;

A composite material is made up of two phases, the matrix, and the reinforcing materials. The reinforcing material is embedded over matrix material. The reinforcing material works to make the matrix material harder. A fibreglass reinforced composite was developed using E-glass fibre reinforcement and epoxy resin matrix. The composites were produced using the hand lay-up technique with varying fibre percentage of 9%, 13% and 25% by weight percentage of fibreglass mat at orientations of 0°, 15°, 45°, and 90° chosen at random. A 13% by weight percentage of chopped mat was also developed for purpose of comparison. The fabricated composites were subjected to tensile test, flexural test, impact test, punch shear test and hardness test to ascertain the appropriate fibre contents and orientation that is optimum for the manufacture of headgears. Analysis of Variance was carried out to determine level of significance and percentage contribution of the parameters. The results show that both fibre orientation and percentage of fibre content reinforcement of have significant influence on the strength and fracture energy of the composite .The fibre orientation has a higher impact on the strength of the composite (79.74%) while the percentage of fibre reinforcement has a lesser impact on the tensile strength of the composite (20.26%). However, the fibre orientation has a lesser impact on the fracture energy of the composite (24.54%) while the percentage of fibre reinforcement has a higher impact on the fracture energy of the composite (75.46%) The result from this study shows that the increase in fibre content increases flexural strength and impact toughness of the fibreglass reinforced composite. A fibre orientation of 90° and fibre reinforcement of 25% wt. was determined to be optimally suitable for the manufacture of headgears.
Haotian Yan
Modern Mechanical Engineering, Volume 10, pp 39-49;

In this paper, we use Port-Hamiltonian framework to stabilize the Lagrange points in the Sun-Earth three-dimensional Circular Restricted Three-Body Problem (CRTBP). Through rewriting the CRTBP into Port-Hamiltonian framework, we are allowed to design the feedback controller through energy-shaping and dissipation injection. The closed-loop Hamiltonian is a candidate of the Lyapunov function to establish nonlinear stability of the designed equilibrium, which enlarges the application region of feedback controller compared with that based on linearized dynamics. Results show that the Port-Hamiltonian approach allows us to successfully stabilize the Lagrange points, where the Linear Quadratic Regulator (LQR) may fail. The feedback system based on Port-Hamiltonian approach is also robust against white noise in the inputs.
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