Engineering Transactions: A Research Publication of Mahanakorn University of Technology

Semi-blind with Mixing Parameter Receiver for Channel Estimation in TDD massive MIMO Systems

Thu, 27 Jun 2024 00:00:00 +0700

This paper presents the application of the semi-blind principle to an LS algorithm to estimate the channel state information of the TDD massive MIMO systems. The mixing parameter is used to mix the channel coefficients that are estimated from the pilot and data signals. The orthogonal codes are used to identify base stations and users to reduce the effect of full pilot contamination. The simulation results show that the proposed semi-blind algorithm can improve the SINR performance and the achievable downlink rate of downlink systems, which are higher than those of the LS algorithm using the orthogonal code and the conventional LS algorithm.

Study of brain MRI Image classification by Convolutional Neural Network

Sirapoap Thamthum, Suchada Sitjongsataporn — Thu, 27 Jun 2024 00:00:00 +0700

This research presents a method for classifying Magnetic Resonance Imaging (MRI) images using Convolutional Neural Networks (CNNs). The CNN model is trained on a labeled dataset of MRI images, which allows the model to learn patterns and specific features of MRI images related to various diseases or medical conditions. Simulation result show that the appropriate model for classification of Alzheimer’s brain MRI image is ResNet50. This is used the less epochs for training compared to MobileNetV2 and efficientNetB7 with high accuracy.

Design and Implementation of an Explorer Robot Suspension Based Rocker-Bogie Mechanism

Somkiat Maithomklang, Sorasak Kanjan, Sakan Changklin , Kritsada Wichienlam — Thu, 27 Jun 2024 00:00:00 +0700

Robots are essential in the industrial sector, especially when it comes to surveying and ensuring safety. There is an increasing need for robots that can navigate and work in challenging and dangerous environments, which are difficult for humans to access. As a result, the researchers are actively studying and developing an explorer robot using a rocker-bogie suspension system. To create the suspension model, the researchers used computer-aided design-based analysis in SolidWorks and finite element analysis (FEA) to evaluate its structural strength. Before commencing construction, it is critical to simulate the suspension movement of the explorer robot. The explorer robot’s study findings and design have dimensions of 52, 100, and 37 cm, as well as a weight of 35.90 kg. Under the specified conditions, the analysis of the explorer robot suspension’s structural strength revealed a maximum stress concentration of 14.538 MPa, along with a safety value factor of 16.852. The explorer robot’s suspension design accommodates a required load of 2,479 N. In addition, the researchers conducted simulations to model the physical characteristics of movement in various scenarios. The suspension of the Explorer robot retains its original design features

Design and implementation of Motor Speed Control for the automatic cutting and wrapping machine

Nattapong Paenoi, Natcha Salamat — Thu, 27 Jun 2024 00:00:00 +0700

This paper presents the design and implementation of a motor speed control system for an automatic cutting and wrapping machine. The idea is to reduce the cost of purchasing expensive machinery. The prototype machine will have the ability to automatically cut and wrap the small products. The aim of this work is to create a prototype automatic motor speed controller in order to control the motor speed up and down for an automatic candy cutting and wrapping machine. This work leads to reduce the weight of uneven candy pellets and reduce defects in the production line. The dimensions of the machines in the factory are width 63 cm., length 170 cm., height 130 cm. and the dimensions of the prototype kits are width 50 cm., length 50 cm., height 40 cm. using an Arduino Uno R3 Controller for controlling the main operations. And the motor speed can be adjusted according to the distance of the sugar lines used for cutting to the pellet candy and to apply a set of sensors and IoT systems to use with smartphone. The experimental results at a speed of 450 rpm were compared between the motor speed and the candy weight loss. The results of the candy weight are closed to the standard as 7.5 grams/pellet. And when comparing the results of the waste before and after working with the machine's working time of 7 hours/day, it was found that after Improvements can reduce the amount of waste by approximately 275 pieces per day.

A review of heat transfer enhancement with baffle turbulators

Thu, 27 Jun 2024 00:00:00 +0700

Surface modification, turbulator insertion, duct/tube form modification, and nanofluid application are among the most extensively used heat transfer improvement techniques. Surface modification with artificial roughness, such as baffles and similar devices, is one of the most effective ways to generate turbulence in air channels used as heat exchangers, and solar air heaters. In general, the usage of rough surfaces resulted in both preferred heat transfer enhancement and an undesirable friction loss. To assess the augmented system's practical use, the overall thermal performance is assessed while accounting for both heat transfer augmentation and friction loss. The baffle turbulator is one of the passive methods to improve heat transfer rates. This research focuses on a literature review of solar air heaters using baffle turbulators. The research discusses the heat transfer characteristics and thermal performance enhancements of several types of baffle turbulators.

Influence of transverse baffles on thermal enhancement characteristics

Thu, 27 Jun 2024 00:00:00 +0700

The objective of this paper is to investigate the influence of transverse baffles (TB) on Nusselt number (Nu), friction factor (f), and thermal enhancement factor (TEF) in the Reynolds number (Re) range of 6,000-24,000. In the experiments, the transverse baffles (TB) have the blockage height ratio (e/H) equal to 0.30, while keeping the baffle pitch to baffle height ratio (P/e) constant at 2. The results showed that for TB (e/H=0.30, P/e=2), the highest Nusselt number (Nu) value is 96.15 and the Reynolds number of 24,000. The transverse baffle (TB) gives the highest thermal enhancement factor (TEF) of 0.97 at a Reynolds number of 6,000.