Suranaree Journal of Science and Technology

AN EARTHQUAKE VULNERABILITY ASSESSMENT OF ASAN TO INDRACHOWK SETTLEMENTS OF THE CITY CORE OF KATHMANDU

2025-09-08T08:59:53+07:00

Nepal, a South Asian Himalayan country, is particularly vulnerable to earthquake disasters due to its young geology, hilly terrain, and widespread non-engineered infrastructures. The country exhibits significant physical and cultural diversity in terms of geology, altitude, and location. Social and cultural activities were virtually prohibited for many years following the earthquake; the physical damage from past earthquakes was less severe than anticipated in comparison to the social and cultural consequences. Based on the study, this research proposes a tripartite mitigation framework for physical, social and cultural vulnerability of the Asan to Indrachowk settlements in Kathmandu’s city core, an area critical for its socio-cultural and economic significance, employing mixed-methods analysis and Analytic Hierarchy Process (AHP). The pragmatism/mixed method has been employed to find composite vulnerability. Physical vulnerabilities arise from non-engineered, high-rise buildings, social vulnerabilities from limited community resources, and cultural vulnerabilities from the erosion of traditional practices. The research outcome revealed physical (63.25%, extreme), social (41.3%, highly) and cultural (44.15%, highly) vulnerable. The composite vulnerability score of 57.23% indicates extreme vulnerability, necessitating urgent retrofitting and cultural preservation measures.

PETROGENETIC STUDY ON ULTRAMAFIC–MAFIC SUITE OF SATHYAMANGALAM SCHIST COMPLEX (SOUTH INDIA)

2025-06-26T15:58:51+07:00

The ultramafic–mafic suite exposed in the Gobichettipalayam region of Tamil Nadu, forming part of the Sathyamangalam Schist Complex (SSC), displays a well-layered stratiform structure aligned along the Bhavani Lineament Zone. Field evidence such as rhythmic layering, chromitite lenses, and preserved cumulate textures indicates an intrusive origin with co-magmatic relationships. The sequence comprises pyroxenite at the base, overlain by metagabbro and capped by meta-anorthosite, all emplaced into high-grade metamorphic terrain and later deformed under upper amphibolite to granulite facies. Petrographic analysis reveals adcumulate textures in anorthosites with calcic plagioclase, garnet-bearing metagabbros with relict pyroxenes, and clinopyroxene-rich pyroxenites, pointing to fractional crystallization and metamorphic overprinting. Major, trace, and REE geochemistry show a tholeiitic trend, with meta-anorthosites enriched in Al₂O₃ and CaO and depleted in TiO₂, K₂O, and P₂O₅. Tectonic discrimination diagrams and REE patterns suggest an arc-related, supra-subduction zone setting, marked by negative Eu anomalies and HREE enrichment, indicating plagioclase and pyroxene fractionation.

A NOVEL TWO-LAYER VERTICAL WIRE MEDIUM FOR ENHANCING MONOPOLE ANTENNA GAIN IN LoRaWAN-BASED IoT APPLICATIONS

2025-09-15T08:59:58+07:00

This research proposed a novel approach to enhance the gain of a monopole antenna. The design integrated a wire medium metamaterial structure and a dielectric material with a quarter-wavelength monopole antenna to improve gain performance, while maintaining compact size and lightweight characteristics. The antenna was designed to operate at a frequency of 922.5 MHz for use in a long range wide area network (LoRa WAN). The proposed structure consisted of a quarter-wavelength monopole antenna surrounded by a two-layer vertical wire medium. A polyamide material, shaped into a cylindrical form, was used as a spacer between the two layers of the vertical wire medium. Simulation results demonstrated that the dielectric wire medium significantly enhanced the gain of the monopole antenna from 4.5 dBi to 12.3 dBi-an improvement of 7.8 dBi. The antenna also exhibited a symmetric radiation pattern with reduced side lobes. The proposed technique enhanced the performance of existing systems without necessitating additional power input. To validate the simulation results, a prototype antenna was fabricated and experimentally tested. The measured results demonstrated good agreement with the simulations in terms of reflection coefficient, VSWR, radiation pattern, and gain.

GLOBAL PERSPECTIVES ON RC BEAM DESIGN: A COMPARATIVE STUDY OF CONCRETE CONTRIBUTION TO SHEAR STRENGTH ACROSS INTERNATIONAL STANDARDS

2025-09-17T15:41:50+07:00

Concrete and shear reinforcement give Reinforced Concrete (RC) beams their shear resistance. This study analyzes several national regulations and examines how concrete affects the shear strength of RC beams. Three-point loading was tested on six RC beams that were 150 mm wide, 300 mm deep, and 2000 mm long, made of M35 grade concrete. The optimal span of the supports was 1700 mm. The longitudinal reinforcement varied, with B1 to B3 being conventional mixes and B4 to B6 being 10% Metakaolin, 10% Flyash, 80% OPC, and 1.5% glass fiber. Measured experimental shear strengths were compared to the theoretical values found in ACI 318-19, Eurocode 2, and IS 456:2000. According to IS 456:2000, the comparison showed that concrete’s shear strength penetrates its shear resistance. Closer estimates to experimental results were given by codes like ACI 318-19 and Eurocode 2, with Eurocode 2 being the most accurate, as demonstrated by ACI 318-19 and IS 456:2000. According to the study’s findings, IS 456:2000 tends to underestimate shear strength and suggests modifications to lessen reliance on shear reinforcement. These results force researchers and structural engineers to choose appropriate shear strength values for RC beam designs that are both safe and economical.

OPTIMAL DESIGN OF A SILENCER FOR ENHANCING NOISE REDUCTION IN A 5G BASE STATION

2025-09-29T14:52:19+07:00

A 5G base station, also referred to as a 5G cell site or 5G cell tower, is a crucial component of a 5G wireless network infrastructure. It is responsible for providing wireless connectivity and enabling high-speed data transmission for 5G-enabled devices, such as smartphones, tablets, and other Internet of Things (IoT) devices. The compo-nents of the 5G base station are significantly more powerful than those of previous stations, such as 2G, 3G, and 4G. As a result, the cooling systems require more power and cause noise pollution to the environment. This study focuses on developing a novel silencer to reduce acoustic noise from servers in a 5G base station. The proposed silencer is made from high sound-absorbing materials to reduce noise. In addition, the silencer is designed with optimal vertical and horizontal ribs to enhance noise reduction while retaining comfortable airflow. The design performance was verified through simulations and validated by experiments.

PET FOOD INDUSTRY APPLICATION OF LEAN AND ECRS TECHNIQUES TO IMPROVE PROTEIN POWDER DELIVERY PROCESS

2025-09-01T09:21:43+07:00

This study aimed to improve the product delivery process by focusing on a case study of a protein powder manufacturer in the pet food industry. Various steps in the process were examined, on a questionnaire, participatory observation, and a process flow chart. Pareto analysis was used to evaluate activity value and prioritize issues needing improvement. In addition, the causes of delays in the delivery process were assessed using the Why-Why analysis tool. The ECRS tool was applied to improve the product delivery process. The efficiency of the process was compared before and after this improvement using descriptive statistics. Based on the study result, batch and pooled sample quality analysis steps, along with associated waiting times, accounted for 99.68 percent of the total delivery process duration. The study achieved a 50.29 percent reduction in total delivery process time by improving the quality analysis process to facilitate better communication of results and organizing the sample pickup logistics. This also resulted in a 69.0 percent reduction in time spent on non-value-added (NVA) steps and a 34.61 percent reduction in time spent on non-value-added but necessary (NNVA) steps, along with a 51.02 percent decrease in the amount of minimum cash required to support operations, allowing the company to reallocate working capital toward value-added activities. These improvements enhanced customer satisfaction, as demonstrated by internal audit feedback and the repeat purchase behavior observed during the post-implementation period, indicating a positive shift in service perception.

ANALYZING THE TRAVEL INTENTION OF ELDERLY PASSENGERS IN THAILAND’S PUBLIC TRANSPORTATION SYSTEM: A STRUCTURAL EQUATION MODELING APPROACH

2025-10-14T10:53:10+07:00

This study aims to investigate the factors influencing the intention to use public transportation among older adults in Thailand. The analysis was conducted using Structural Equation Modeling (SEM), guided by the Theory of Planned Behavior (TPB) and the SERVQUAL framework. Data were collected from 2,250 individuals aged 60 and above, across five regions of the country, through structured questionnaires and in-depth interviews. The survey instrument consisted of sections on demographic information, travel experience, and perceived service quality. The findings reveal that passenger satisfaction plays a significant and strong role in shaping the intention to use public transport. Positive attitudes toward public transportation were found to have both direct and indirect effects mediated by satisfaction on the behavioral intentions of elderly individuals. In contrast, habitual use of private cars exerts a negative influence on the intention to use public transport. This highlights the need to foster an environment that supports the development of new travel habits, encouraging older adults to shift from private vehicle dependence to public transportation. These insights offer valuable implications for policymakers and relevant stakeholders in understanding the perspectives and needs of elderly public transport users. By implementing a policy framework that promote inclusive and age-friendly public transportation, the results of this study can contribute to advancing social equity and long-term societal resilience.

OVERVIEW OF MULTIPORT EV FAST CHARGING STATIONS WITH FLOATING SOLAR PV USING MODIFIED Z-SOURCE INVERTER TECHNOLOGY

2025-09-29T14:30:25+07:00

Electric cars (EVs) are growing in popularity, thus infrastructure for charging them must be sufficient to make refueling them as pleasurable as driving a conventional car. In this regard, advancements in Multiport Fast-charging (MFC) offer promising alternatives. MFC systems can use floating solar PV (FPV) and innovative modified Z-source inverters (MZSI) to adjusted to the evolving demands of EV recharging. MZSI is better for EV charging stations because of the recent increase in EV usage. For the charging station design to integrate several sources and offer a multiport charging option, an efficient inverter was required. This article describes how MZSI is made for multiport EV charging stations using FPV and the grid. The suggested MZSI is positioned between the input and output sides to increase the voltage in response to the battery side's needs. This converter architecture has five operational modes : FPV-Grid, FPV-battery, grid-battery, battery-grid, and FPV to grid and battery. Some studies use two connections for charging, producing 1 kW at each charger. Both chargers generate 2 kW with 90% efficiency as a result. Based on FPV, the review suggests that MZSI would be a better choice than a multiport EVCS. Our analysis focuses on integrating multiport converters with FPV energy and offers details on a unique MFC topology architecture for EV charging stations that employs MZSI. For FPV-based multiport EVFCS, we note that a modified Z-source inverter (MZSI) offers greater efficiency and adaptability, cheap cost, control mechanism, and straight forward construction.