European Journal of Engineering and Technology Research

Multi-Objective Optimization of Skd11 Steel Grinding Process using Entropy and RAM Methods

Bui Thanh Danh — 2025-05-10

Grinding is a prevalent method employed for machining products demanding high precision within the mechanical processing industry. This study focuses on the multi-objective optimization of the SKD11 steel grinding process on a surface grinding machine. An experimental procedure, encompassing a total of nine trials, was designed utilizing the Taguchi method. Within each trial, variations were introduced to three cutting parameters: workpiece velocity, feed rate, and depth of cut. Concurrently, measurements were conducted for four objectives, also designated as criteria: surface roughness (Ra), cutting force component along the x-axis (Fx), cutting force component along the y-axis (Fy), and cutting force component along the z-axis (Fz). The ENTROPY method was deployed for the computation of criteria weights, while the RAM method was utilized to resolve the multi-objective optimization problem. The results yielded optimal values for workpiece velocity, feed rate, and depth of cut, corresponding to 10 m/min, 4 mm/stroke, and 0.01 mm, respectively. Associated with these optimal cutting parameter values, the objective values for Ra, Fx, Fy, and Fz were determined to be 0.49 mm, 18.4 N, 15.2 N, and 28.4 N, respectively.

Comparison of Mid-IR LED-Based and MEMS Hotplate-Based Photoacoustic CO2 Sensors

Lucky Ahmed Ishaku — 2025-05-16

The focus of this work is the development of two types of low-cost photoacoustic (PA) CO2 sensors, the first was made from mid-infrared (mid-IR) light emitting diode (LED) and the second was made from micro-electro-mechanical system (MEMS) hotplate. Both sensors use MEMS microphones for the detection of the generated acoustic signal. These sensors have advantages of low power consumption, small size and low cost. Analyses of results from both sensors show that temperature change (within−20°C–50°C range) affects their signal amplitude and sensitivities. Results also show that the absence of buffer gas in the cell reduces the PA signal amplitude. Furthermore, comparison of results from the sensors indicate that the LED sensor is more sensitive by about one order of magnitude while the hotplate sensor, which is less expensive, has a better noise performance. This is the first time that such comparison is done and it is important because it reveals the advantages and limitations of these sensors. The findings is vital for determining which sensor will be suitable for certain applications, considering the cost.

Study of Dynamic Fields in an Enclosure with Two Openings Heated by a Cylindrical Heat Source

Christian Anicet Koueni Toko — 2025-05-24

The objective of this work is to understand and predict the gas flows generated in an enclosure with an aspect ratio H/L= 0.83, having 02 openings located at the floor level and heated by a linear solid heat source. 02 enclosures Case 23 and Case 21 were studied. In these enclosures the openings are symmetrical and of the same sections. In the enclosure Case 23, the heat source is 3 mm above the floor and located at the position x+ = 0. In the enclosure Case 21, the heat source is at the position x+ = 0.24. The numerical computations of the velocity fields, pressure fields and mass flow rates will be carried out using the Direct Numerical Simulation (DNS) method and considering that a constant temperature is initially imposed on the heat source, that the enclosure is in thermal equilibrium with the outside and that there is no movement of gases at the openings. The results show that in the Case 23 enclosure, the velocity plume is turbulent and centered while in the Case 21 enclosure the velocity plume is strongly deflected near the side wall located at x+ = 0.5. This deviation can be due to the Couanda effect. In the Case 23 and Case 21 enclosures, we observe on each opening an incoming mass flow of fresh air and an outgoing mass flow of hot gases. Part of the hot gas flows descending towards the floor of the enclosures exits the enclosure and the other part is entrained by the velocity plume. The numerical computations of differential static pressure show that near the floor the values of differential static pressure are negative and outside the vicinity of the floor they are positive and increase with the height of the enclosure. The static pressure profiles have the same appearance. The comparisons of the static pressure profiles obtained in the Case 23 enclosure with the results of the literature are consistent.