Journals of Universiti Tun Hussein Onn Malaysia (UTHM)
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Seasonal Impact of Water Parameters Variation on Signal Propagation in Underwater Communication Systems
Get PDFThe study explores how environmental variations affect signal propagation in freshwater bodies, focusing on five key sites: Niger River, Asejire Dam, Ede Dam, Osun River, and Eti-Osa River. Employing laboratory-based quantitative analysis, parameters such as temperature, salinity, pH, turbidity, and total dissolved solids (TDS) were measured using standard instruments. Distinct seasonal trends emerged—temperature increased by an average of 8°C in the dry season, while turbidity and TDS rose notably during the rainy period, ranging from 30–150 NTU and 25–80 mg/L in the dry season to 41–200 NTU and 30–120 mg/L in the rainy season. These variations directly influenced acoustic signal performance. The data revealed that higher temperatures improve signal velocity and reduce attenuation, whereas increased turbidity, TDS, and salinity contribute to greater scattering and absorption losses. The novelty of this work lies in its integrated assessment of multi-parameter water quality influences on underwater signal transmission, emphasizing the dual-season comparative approach within tropical freshwater systems. Unlike prior studies that generalized oceanic models, this research contextualizes findings within inland aquatic environments relevant to Nigeria. The study contributes to the existing body of knowledge by quantitatively linking environmental conditions with communication efficiency, establishing that signal reliability in Underwater Communication Systems (UWCS) is seasonally dependent. In conclusion, the results underscore the necessity of adaptive communication models that account for local hydrological dynamics to minimize signal degradation and optimize transmission efficiency across varying aquatic conditions.
Thermophysiological Comfort Assessment of Football Jersey Fabrics used in Hot and Humid Weather
Get PDFOptimizing thermophysiological comfort is crucial for enhancing athletic performances and well-being during intense exercise in hot and humid climates. This study assessed the comfort properties of four commercially available 100% polyester microfibre fabrics used in football jerseys: mini mesh (MM), polar eyelet (PE), eyelet (EY), and interlock (IT). Fabric assessments were conducted to evaluate thermal resistance, water vapour resistance, water vapour permeability, air permeability, and moisture management properties. Among the fabrics, the PE fabric demonstrated to give the most superior thermophysiological properties, with the lowest thermal resistance (0.009 m²K/W), the lowest water vapour resistance (0.44 m²Pa/W), and the highest water vapour permeability (237.7 g/m²/day) and air permeability (2149.2 mm/s). These values are attributed to the fabric’s porous, open-knit structure that enhances heat and moisture dissipation, resulting in improved breathability and wearer comfort. Statistical analysis confirmed significant differences among the fabric structures, reinforcing the influence of fabric design on comfort performance. The findings suggest that, among the fabrics, the PE fabric performs better as sportswear for tropical climates like Malaysia
Evaluation of Traffic Noise Exposure in Old Folks\u27 Homes, Batu Pahat, Johor
Get PDFExcessive noise exposure can adversely affect the elderly, causing sleep disorders, depression, and stroke. To analyze the noise levels in old folks’ homes, this study used a data logging sound level meter to evaluate traffic noise levels of three old folks’ homes located along the busy road of Jalan Kluang during peak hours of weekdays and weekend (7.30am to 9.30am and 4.30pm to 6.30pm). Traffic counts according to different classes were carried out during the first hour of the survey. The study showed that traffic volume did not affect noise levels at Rumah Sejahtera Batu Pahat and Sherun Old Folk Home (BP), but a positive correlation was found at Healthlife Old Folks Home. Noise levels (LAeq(2hrs)) recorded for Rumah Sejahtera Batu Pahat, Sherun Old Folks Homes (BP), and Healthlife Old Folks Homes were 75 dBA, 67 dBA and 70 dBA, respectively. They are all above recommended values set by the Department of Environment Malaysia (DOE) which is 60 dBA for daytime. The noise levels at nearby buildings, including old folks\u27 homes, are likely to be around or exceeding the DOE standard. The research is essential as it evaluates the seriousness of traffic noise pollution around the old folks’ homes along Jalan Kluang. This study will be helpful for future research and development of built-environment plans
Simulation of Sustainability and Energy Efficiency of NH3/CH4 Co-firing Flames in Swirl Combustors
Get PDFAmmonia has emerged as a promising candidate due to its carbon-free and renewable nature. As a green energy carrier, ammonia can significantly reduce greenhouse gas emissions, but its utilization as a fuel faces challenges, including lower laminar flame speed, lower adiabatic flame temperature, higher ignition energy, narrower flammability limits, and increased nitrogen oxide emissions. To investigate their sustainability and energy efficiency, the study aims to simulate NH3/CH4 co-firing flames in a swirl combustor. The research focuses on premixed NH3/CH4/air reactants with varying methane fractions (0%, 25%, 50%, 75%, and 100%) at standard atmospheric pressure. The study simulates the steady flow field using ANSYS Fluent and the RNG k-ε model and uses the results for unsteady simulations. Through the simulation, it indicates a trade-off between CO2 and NOx emissions. High CO2 emissions correspond to the complete combustion of methane, while low CO2 emissions indicate incomplete combustion, resulting in unburned methane. From the simulation results, 25% of methane fraction, with its highest energy efficiency and temperature, emerges as the most sustainable despite producing unwanted NOx emissions. Overall, 25% of methane fraction results are identified as the optimal mixture for energy production, highlighting the need for balancing efficiency and emission controls in sustainable combustion processes
Finite Element Model for Pull-Out Test of Reinforcement Embedded in Confined Concrete
Get PDFA finite element (FE) model was developed to simulate the pull-out test of steel rebar embedded in concrete confined with pre-tensioned steel straps. The model treated both the concrete and steel rebars as refined solid elements, enabling explicit representation of their deformations. A surface-to-surface contact model was employed at the concrete-rebar interface to ensure accurate load transfer. The importance of using a confined concrete model capable of accurately simulating nonlinear behavior under high confining pressures was emphasized in the modelling process. For this purpose, the concrete damaged-plasticity (CDP) model was adopted. Multiple pull-out tests were simulated using this approach, and comparisons with experimental data demonstrated that the proposed FE model accurately reproduced bond stress-slip responses. Additionally, the model successfully captured different failure modes, including splitting failure in specimens without confinement and pull-out failure in confined specimens
Advancement of Big Data Analytics Capabilities in Construction Industry: A Resource-Based Theory and Dynamic Capabilities Perspective
Get PDFThe potential of big data analytics (BDA) to boost productivity and performance is reshaping business models in various industries including construction. As construction data grows exponentially, BDA’s role in driving a competitive edge becomes increasingly critical. Through advancements in big data technology, big data analytics capabilities (BDAC) have emerged as essential tools for construction organizations to transform their organizational resources into competitive advantages. However, while existing studies highlighted the benefits of BDA in construction, they paid little attention to the specific capabilities required to leverage these advantages from a strategic management perspective. Hence, this study aims to identify the BDAC that enables construction organizations to strategically leverage their resources for BDA adoption. To achieve the aim, this study employed the systematic review approach following the PRISMA methodology in which 781 relevant publications from Scopus and the Web of Science databases were identified. Following a set of inclusion and exclusion criteria, 58 articles were included in the review to identify the critical dimension of BDAC, grounded from resource-based theory (RBT) and dynamic capabilities theory (DCT) alongside literature on BDA. Findings were then validated through semi-structured interviews with big data experts in Malaysia’s built environment that supports the outcomes. This study identified eight dimensions of BDAC which further categorized into three domains of technological capability, human capability and organizational management capability necessary for the conceptualization of BDAC. The findings offer specific capability domains necessary to foster BDA adoption among construction organizations, potentially shifting their competitive strategies through innovative use of BDA
Electromagnetic Simulation of Metamaterial Lens Antenna with Negative Refractive Index at 28GHz
Get PDFLens antennas are widely used to achieve multi-beam radiation patterns. When designed with negative refractive index (NRI) materials, these patterns improve further due to reduced lens thickness. Evaluating radiation characteristics requires electromagnetic simulation tools, but only a few can accurately model NRI properties. This paper explores the feasibility of using HFSS for such simulations. The study outlines the modeling approach, parameter settings, and computational techniques. Key results, including near-field, aperture amplitude and phase, and radiation patterns, are analyzed. To ensure accuracy, the simulated outcomes are compared with theoretical calculation
Evaluating Thermal Exposure Effects on Dielectric and Structural Properties of Water Treatment Residuals
Get PDFEffective handling of water treatment residuals (WTRs) is essential due to their substantial volume and environmental impact. This study investigates the effects of two thermal treatment methods—microwave and oven heating—on the dielectric properties and morphological changes of WTRs. Utilizing Microwave Non-Destructive Testing (MNDT), dielectric permittivity was measured using a vector network analyzer, while morphological transformations were assessed through scanning electron microscopy (SEM). Microwave heating at power levels of 450W, 600W, and 800W resulted in a consistent increase in dielectric permittivity, ranging from 0.94 to 1.26, indicating improved dipolar alignment and material response. In contrast, oven heating produced less predictable results, with dielectric permittivity decreasing from 1.03 at 100°C to −0.55 at 200°C. SEM analysis further confirmed that microwave-treated samples exhibited more uniform structural modifications, including particle fusion and smoother surface morphology, compared to the more fragmented and heterogeneous changes observed under oven heating. The findings support the potential of microwave heating combined with MNDT as a more effective and non-invasive method for characterizing and transforming WTRs. This approach could contribute to the development of more efficient and sustainable residual management processes in the water treatment industry
Synthesis and Characterization of Cinnamon Bar Soap from Waste and New Cooking Oils: A Comparative Study
Get PDFImproper disposal of waste cooking oil led to environmental risks. Converting waste cooking oil into handmade soap, especially by adding cinnamon, offers a sustainable reuse method. This study investigates cinnamon’s impact on soap’s cleaning ability by using cold process method. The fundamental materials used in this process such cooking oil, sodium hydroxide (NaOH), distilled water, and cinnamon. Cinnamon was added with variation concentration from 0g, 3g, 6g, 9g, and 12g for both using new cooking oil (NCO) and waste cooking oil (WCO). Soaps were evaluated for colour, pH value, FTIR analysis, moisture content, swelling test, and stain removal test. The results indicate that the soap sample from new and waste oil without cinnamon appeared nearly white, while soap samples with highest concentration of cinnamon were dark brown. Both soap from new and waste oil had a pH level of 8 and a moisture content of 11.11%. Cinnamon bar soap using new oil and 6 grams of cinnamon has the highest degradation rate at 12.31%, and cinnamon bar soap using waste oil and 3 grams of cinnamon has the lowest at 6.46%. The soap in vinegar solution showed the most chemical reaction with a pH level of 2, while the soap observed remain stable in the salt solution due to its pH value of 9. Both bar soaps from NCO and WCO are equally effective at removing stains. Specifically, both soap from new and waste oil removed 94% of soy sauce stains. For chili sauce stains, the soap using new oil removed 87%, while the soap using waste oil removed 88%. However, for lipstick stains, both soaps only managed to remove 80% of the stain. This study suggested that bar soaps made from WCO with cinnamon additives can be used as raw material in production of high-quality soap which promotes environmental responsibility and contributes to sustainable waste management
TiungLap: A Quadcopter Drone for Window Cleaning with an Integrated Pressure Washer Tethering System
Get PDFThe TiungLap drone, developed to address the high risks and inefficiencies associated with traditional high-rise window cleaning, integrates a tethered high-pressure washer system to improve safety and operational time. The drone features advanced GPS navigation, real-time monitoring, and LiDAR-based obstacle avoidance for precise cleaning in complex environments. The objective of this study was to optimize the thrust, power consumption, and control stability of the drone during cleaning operations. Utilizing four X9 motors, the drone achieved a maximum thrust of 21.23 kgf per motor, ensuring sufficient lift to handle its 22 kg payload. Power analysis revealed the motors consumed 4790.2W each, contributing to a total system power consumption of 7421.25W. A key challenge was stabilizing the drone under the influence of external forces from the tethered hose, which was addressed through manual tuning of the PID controller. This tuning reduced roll error by 94.9% and pitch error by 87.8%, significantly improving drone stability. Future research should focus on enhancing flight endurance and further optimizing control algorithms to handle external forces more effectively