Engineering Transactions: A Research Publication of Mahanakorn University of Technology

Influence of nano-reinforcement through a combination with traditional fiber reinforcement in multi-scale laminate composites structural - Review

2025-03-27T18:15:01+07:00

The purpose of this study is to present the influence of nano-reinforcements graphene platelets (GPLs) with a sector of fiber-reinforced composite structures. Recently, GPLs has been widely used in composite structures due to its excellent properties such as high elastic modulus, high strength, large specific surface area, low density, etc. Therefore, these prominent properties are the promising choices for the development of novel types of laminated composite structures named multi-scale laminated composite. However, the paper focuses on the important effect of GPLs on the development of novel types of laminated composite structures, such as aspect ratio (l/d), weight fraction (wt.%), distribution of nano-reinforcements and aligned reinforcing fibers, respectively.

Recurrent Neural Network-based Model for Electrocardiogram Classification

2025-05-14T22:30:25+07:00

This paper presents the study of deep learning models for Electrocardiogram (ECG) classification. Abnormalities of heart diseases can detect and diagnose by ECG signal. Deep learning models have been interested for arrhythmia detection and classification from ECG signal. Recurrent Neural Networks (RNNs) represent a different category of artificial neural networks that incorporate feedback mechanisms. It makes suitable for capturing temporal dependencies in the time series data from ECG electrical signal. Long short-term memory (LSTM) network and gated recurrent unit (GRU) are types of RNN designs. The objective of this paper is to compare the performance of conventional RNN with LSTM and GRU models for capturing the long-term relationships in ECG data. Simulation results show that GRU model can classify the heart’s diseases more accuracy than simple RNN and LSTM model.

Preparation of mixed fuel pellets from used polypropylene canvas and biomass

2025-06-12T17:44:52+07:00

This research is an energy feasibility study on the production of fuel pellets from recycled polypropylene canvas and biomass materials, i.e. corn cobs and rice straw. The properties of mixed fuel pellets were analysed in order to find the appropriate proportion of used polypropylene canvas and biomass materials and to produce pellet fuels that meet Thailand’s pellet fuel standards for industrial applications, TIS 2772-2560. The ratio of polypropylene and biomass were varied into 3 ratios: 10:90, 20:80 and 30:70. The palletization was performed by a 3 hp pellet machine by using a 20 percent by mass of tapioca starch water was used as a binder. The results showed that the moistures of mixed fuel pellets produced from used polypropylene canvas with corn cobs at ratio 10:90, 20:80 and 30:70 were 9.09, 7.97 and 5.96 percent by mass, respectively. Heating values of 20.67, 21.69 and 24.89 MJ/kg, and ash contents of 1.86, 2.58 and 2.76 percent by mass were found, respectively. Whilst the moistures of mixed fuel pellets of used polypropylene canvas with rice straw at 10:90, 20:80 and 30:70 were 10.51, 10.42 and 6.99 percent by mass, heating values of 19.90, 21.14 and 22.95 MJ/kg, and ash contents of 8.49, 9.69 and 10.53 percent by mass were found, respectively.

In conclusion, fuel pellets can feasible be used as fuel due to the high heating value. All fuel pellets properties except bulk density meet the Thailand’s pellet fuel standard for industrial application. The reason of slightly below standard bulk density is might due to the fact that polypropylene canvas has a lightweight property.

Vibration Responses for SDOF System: I – Free and Forced Vibrations with and without Damping

2025-05-18T10:11:58+07:00

This paper presents a comprehensive analysis and clearly explains the responses of vibrating system having single degree of freedom (SDOF), which involved to free and forced vibrations with and without damping. Detailed analysis is given and led to obtaining an analytical closed-form solution. Important results are observed and discussed in the paper. The concepts can be used as a basic to model a more complex system using the multidegree of freedom (MDOF) suitable for numerical techniques.

Vibration Responses for SDOF System: II – Coulomb and Structural Damping

2025-05-18T10:56:47+07:00

The principal objective of this paper is to deal with the vibration analysis of single degree of freedom system with Coulomb damping and structural damping. Closed-form expressions in terms of vibration amplitude or magnification factor and phase angle are derived. Due to the difficulty and complexity in determining the damping value in practical systems, concepts of equivalent viscous damping coefficient are introduced and explained that how to treat and receive this coefficient properly. Important observations are found and clearly discussed herein.