Royal Thai Naval Academy Journal of Science and Technology

Renewable Energy: Trends towards Sustainability in the 21st Century

Pramote Suksirisak — 2025-08-22

This article analyzes the current situation and trends of renewable energy both globally and in Thailand, focusing on the transition from fossil fuels to renewable and clean energy as a solution to reduce greenhouse gas emissions and mitigate climate change. Renewable energy sources, such as solar and wind power, have been continuously growing and their production costs have significantly decreased over the past decade. Thailand has developed a plan to increase the share of renewable energy to 50% by 2026, with a focus on biomass energy in rural areas. However, challenges remain in terms of infrastructure development and policy adjustments to support a sustainable transition, particularly in developing countries. This paper suggests that research and development of various forms of renewable energy and government support are critical factors in accelerating the transition to a more efficient and cleaner energy system.

Study of Friction Stir Welding Parameters Affecting the Microstructure and Mechanical Properties of Silicon Carbide Reinforced Aluminum 6061

Supparerk Boontein — 2025-08-22

The objective of this study is to investigate the effects of parameters on the metallurgical and mechanical properties of friction stir welding of aluminum AA6061 reinforced with Silicon Carbide micro-particles of 5 microns. A study on the effect of silicon particle addition in friction stir welding using a pinless tool in the first pass showed better silicon carbide dispersion in the welding zone compared to using a square pin tool. A study on the effect of transverse speed 26, 34, and 50 mm/min and rotational speed 920,1,040, and 1,350 rpm on the top welds appearance showed complete welds at all transverse speed which exhibited cracks along the weld line and the lowest hardness value of 54.21 HV. As for the microstructure, uniform silicon carbide particle distribution was observed at a travel speed of 26 mm/min and a welding rotation speed of 1350 round per minute (rpm). This resulted silicon carbide partical dispersed in a homogeneous with aluminum matrix and obtain the highest hardness of 77.16 HV.

Study on the Energy Absorption Capacity of Foam-Filled Thin-Walled Tubes with Polygon Cross-Sections under Torsional Loading

somya poonaya — 2025-08-22

This investigation aimed to study the energy absorption capacity of thin-walled tubes with polygon cross-sections under torsional loading. The tube cross-sections included square, hexagonal, octagonal, decagonal, icosagonal, hexacontagonal, octacontagonal, and circular shapes. Foam densities of 50, 100, 150, 200, and 250 kg/m³ were considered. The analysis was conducted using experimental and finite element methods.The analysis results concluded that the relationship of the torsional moment-angle curves from the finite element agreed well with experimental results and has an average percentage error is 8.31%. Then, the result of foam densities was found that increasing the foam densities at 0 kg/m³(empty tube) to 100 kg/m³ increase the energy absorption capacity of foam-filled polygon tubes. After that, when the foam density exceeds 100 kg/m³, the energy absorption capacity tends to reach a saturation state (the energy absorption capacity exhibits minimal variation). Furthermore, the result of the polygonal shapes was found that the octagonal, decagonal, icosagonal, hexacontagonal, octacontagonal, and circle tube exhibit the highest and comparable levels of energy absorption capacity. This is followed by the hexagonal tube and the energy absorption capacity of the square tube is the lowest.

Accuracy Assessment of the HEC-RAS 1D Model for Simulating Flow Through Aquatic Vegetation and Obstructions Using Laboratory Open Channel Experiments

Ronnakorn Soisee — 2025-08-22

Flooding represents a severe natural disaster with impacts on human lives and property in numerous regions, affecting both urban and rural areas. Hydraulic models serve as essential tools for water management and preventive planning, requiring accuracy and reliability to analyze and evaluate water flow behavior under various scenarios, thereby systematically supporting engineering decisions and risk management strategies. This research focuses on examining the accuracy of the one-dimensional Hydrologic Engineering Center - River Analysis System (HEC-RAS) model in predicting water flow behavior in open channels containing submerged vegetation and obstructions. The study compares model predictions against results from physical laboratory experiments simulating flow conditions to develop a clear understanding of the model's limitations and potential for practical applications. The experimental methodology involved measuring water levels and flow velocities in conditions with obstructions and simulated structures, then comparing these measurements with values calculated using the HEC-RAS model. Results indicate that the model demonstrated a high level of accuracy in predicting water surface levels across all cases, with NSE values ranging from 0.93 to 0.99. It also showed good accuracy in predicting flow velocity, with the lowest NSE value of 0.62 observed in the bare channel case and the highest value of 0.87 in the artificial grass case. The variability is attributed to the challenges in measuring flow velocity in laboratory conditions due to the turbulent nature of the flow. Therefore, the approach presented in this study can serve as a solid foundation for evaluating and developing models for water management in areas with aquatic vegetation or natural flow obstructions in the future.

High-Performance Liquid Chromatography Using Monolithic Column for Simultaneous Determination of Oxymetazoline Hydrochloride and Xylometazoline Hydrochloride in Nasal Spray Formulations

Somsak Sirichai — 2025-08-22

In this research, a simple and rapid high-performance liquid chromatography for simultaneous determination of oxymetazoline hydrochloride and xylometazoline hydrochloride in nasal spray formulations was developed. The separation was conducted in monolithic column (C₁₈, 100 mm x 4.6 mm). A mixture of acetonitrile (28% by volume) and 0.01% phosphoric acid (72% by volume) was used as the optimal mobile phase, with the flow rate of 2.50 mL/min. All analytes were detected at 220 nm. Under the optimized conditions, oxymetazoline hydrochloride and xylometazoline hydrochloride could be completely separated within 2 min. Calibration curves for standard solution of oxymetazoline hydrochloride and xylometazoline hydrochloride were in the range of 0.50-10.00 mg/L with R² > 0.9987. Limits of detection of oxymetazoline hydrochloride and xylometazoline hydrochloride were 0.03 and 0.04 mg/L, respectively. The proposed method can be used for routine analysis of oxymetazoline hydrochloride and xylometazoline hydrochloride in nasal spray formulations.

Shoreline Extraction Using Water Indices for Nautical Chart Assessment: A Case Study of Hua Hin Beach, Thailand

Aree Hwanlabeh — 2025-08-22

Shoreline change is a crucial indicator of coastal dynamics, impacting maritime navigation, coastal planning, and nautical chart accuracy. In Thailand, traditional hydrographic surveys are limited by time and resources, resulting in outdated shoreline data. This study investigates the use of satellite-based remote sensing and geospatial analysis to assess shoreline change along Hua Hin Beach from 2012 to 2024.

Multi-temporal Landsat imagery from five periods, spaced three years apart, was analyzed using six spectral water indices: NDWI, MNDWI, AWEIsh, AWEInsh, LSWI, and WI2015. The analysis was conducted using Google Earth Engine in combination with the geemap Python API on Google Colab. Shoreline positions extracted with each index were compared to a reference shoreline from Thai nautical chart No.246 (edition 2012), using 430 validation points at 90-meter intervals. Accuracy was evaluated using RMSE and MAE, with WI2015 showing the highest accuracy (RMSE = 7.156 meters).

The best results from WI2015 were used in the Digital Shoreline Analysis System (DSAS) to compute shoreline change metrics; EPR, SCE, and NSM, across 380 transects. The results showed accretion in Zones A and E, erosion in Zones B and C, and stability in Zone D. Based on NSM, shoreline change was classified into Stable (<10 m), Moderate (10–50 m), and Significant (>50 m) categories for resurvey prioritization.

This study highlights the effectiveness of integrating satellite-derived water indices with DSAS for monitoring shoreline change and updating nautical charts in coastal zones.

The development of a sensor experimental set for measuring the oscillation period of a mass attached to a spring for the physics laboratory, Royal Thai Naval Academy

veera boonphud — 2025-08-22

This research aims to develop an experimental setup for Physics Lab 1 at the Naval Academy on Simple Harmonic Motion (SHM) of a mass attached to the end of a spring, making it more modern and highly accurate in measuring the oscillation period using sensors. The research applied an ultrasonic distance sensor module controlled by a microcontroller. The measured value is the average time (Average time) used to calculate the spring constant, and the results are compared with the standard spring constant from PASCO USA. The research findings indicate that the spring constant of the experimental setup has a deviation of only 2.625% when compared to the standard spring constant.

An Optimal Solution for Locating Tide Station Locations in Internal Gulf of Thailand by Using Location Allocation models (P – median)

Sanhanat Itsama-ael — 2025-08-22

The aim of this study is to utilize a location allocation model (P-median) to determine the optimal locations for tide stations in the Historic Bay of Thailand, based on three factors: variation in tide elevation, the number of ports, and population density. Two scenarios were considered: (1) adding new tide stations while retaining all existing ones; and (2) not retaining the existing tide stations but instead rearranging and adding new stations. The results indicated that the second scenario—rearranging the tide stations and adding new ones without retaining the existing stations—provides a more optimal long-term solution in terms of budget efficiency and coverage. This study can serve as a guideline for hydrographic offices to adopt when planning the construction of tide stations.

Study on Storm Surge Warning Guidelines in the Andaman Sea

Saluk Littidet — 2025-08-22

Storm Surge, a coastal flooding phenomenon, is often mistaken for a tsunami due to its destructive impact. Although their impacts may be similarly severe, the forecasting and warning mechanisms for storm surges remain limited in Thailand, especially along the Andaman Sea coast, due to outdated or insufficient early warning systems and a lack of localized, real-time monitoring tools.This study was conducted in response to recurrent storm surge events affecting coastal infrastructure and accelerating coastal erosion in provinces bordering the Andaman Sea. The inability to issue timely alerts has heightened the vulnerability of these regions.The objective of this research is to explore the feasibility of using southwest monsoon wind strength as a predictive indicator for storm surge events. The study specifically examines the official weather warnings issued by the Royal Thai Navy Hydrographic Department and compares them against actual sea level data recorded at four tide gauge stations: Ranong Tide Station, Kuraburi Tide Station (Phang Nga Province) Thap Lamu Tide Station(Phang Nga Province) and Taphao Noi Tide Station (Phuket Province) The study period spans from January 2020 to December 2021 Findings from the two-year dataset (2020–2021) reveal a notable correlation between stronger southwest monsoon winds and periods of elevated sea levels at the monitored coastal stations. Although the timing and magnitude were not always precisely matched in every instance of warning issuance, the general trends show sufficient consistency to suggest that this method holds promise for operational use.

Technical Aspects by Equal-Circumstances for Delimitation between Thailand – Cambodia above Latitude 11 N.

Samharn Dairairam — 2025-08-22

Thailand and Cambodia have claimed continental shelf unilaterally in Gulf of Thailand resulting overlapping claim area. Negotiation between Thailand and Cambodia is contiguous. Presently, the still agreement is the Memorandum of Understanding between the Royal Government of Cambodia and the Royal Thai Government regarding the Area of their Overlapping Maritime Claims to the Continental Shelf, named as Overlapping Claims Area (OCA), done on 18 June B.E. 2554 (MOU 2544). This research aims at finding solution for maritime delimitation between Thailand and Cambodia based on MOU 2544 that the delimitation is above latitude 11 north. The research begins with case study from International Court of Justice (ICJ) and International Tribunal for the Law of the Sea (ITLOS). Geographic Information System (GIS) is the tool for analysis the input data which are topographic information such as general direction of the coast, relevant coastline for finding the relevant area. The overlapping area to be delimited is from the relevant area. The overlapping area stemmed from the relevant area is to lower the different aspects for defining overlapping independently. The maritime area from the research is equitable because the input data, topographic information, is subjective. This research strengthens the equitable solution for delimitation in UNCLOS 1982. The research is from author’s analysis based on geographic circumstances. The other circumstances such as historic title and socialites are none for analysis. The results is the author’s opinion only.

Analysis of Signal Processing System for Electronic Protection regarding the Air Base Security

Watcharapong Ketpan — 2025-08-22

In the operation of unmanned aerial vehicles (UAVs) for perimeter surveillance around airbases, communication systems are paramount, encompassing both video transmission and flight control. The presence of communication signals and/or similar signals can cause significant damage to the UAV's communication links, severely impacting mission performance. This research designs a simulation system capable of modeling signal interference, categorizing it into two types: unintentional and intentional interference. The system employs stochastic geometry, a mathematical model widely used to simulate interference in both wireless communication systems and automotive radar systems, to randomly position interference sources. Furthermore, the two types of interference are designed to have distinct characteristics. Experimental results demonstrate that the system can effectively simulate the impact of both interference types, consistent with the initial hypotheses. The mathematical models employed provide a reference, allowing the obtained average interference values to serve as a baseline for defining the lower bounds of UAV communication systems. Additionally, this research showcases the use of a prototype interference detector utilizing an embedded software-defined radio (SDR) device, the USRP-E312. The results demonstrate its efficiency and suitability for further development into a practical, deployable system.