International Journal of Integrated Engineering
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Investigating The Effect of Piezoelectric Material Type on Biomechanical Energy Harvesting Efficiency
Full text linkThis paper investigates the influence of piezoelectric material type on the performance of biomechanical energy harvesters, with a particular focus on footstep and finger-mouse-click energy-harvesting applications. A combination of design modelling and finite element analysis was employed to assess the energy conversion efficiency of various piezoelectric materials and their adaptability to dynamic forces generated by human motion. The findings indicate that PZT5H is the most efficient material for power generation in footstep harvesters, producing the highest power output of . Moreover, increasing the tip mass in the footstep model was found to enhance the voltage output further, reaching up to 3 . In contrast, PZT4 exhibited the highest energy harvesting efficiency from mouse-click motion, generating a power output of . These findings offer in-depth insight into the capabilities of piezoelectric materials for integration into self-powered biomedical and wearable energy-harvesting applications
Liquid Disintegration Regime of Plain Orifice, Swirl, and Effervescent Atomization: A Review
Full text linkLiquid atomization is a process in which bulk liquid disintegrates into sprays. Numerous liquid atomization mechanism theories have been developed to describe the disintegration process. The disintegration process of bulk liquid into sprays can be characterized using the liquid disintegration regime map. This map illustrates stages of liquid disintegration for a liquid atomization mechanism and is a helpful tool in understanding the underlying physics of a specific liquid atomization regime. However, a liquid disintegration regime map for a type of atomization, namely swirl effervescent atomization, is hardly available and is hypothesized in this paper. Swirl effervescent atomization has broad advantages within the hybrid category, and it is crucial to map the liquid disintegration regime for this type of liquid atomization. The first stage towards mapping the liquid disintegration regime is to review the liquid disintegration mechanisms. This article reviews the liquid disintegration regime of the plain orifice, swirl, and effervescent atomization considering their relation to swirl effervescent atomization
Effect of Specimen Shape on Bond Strength Between Deformed Steel Rebars and Normal Concrete
Full text linkThe study of the bond between deformed steel rebar and concrete is essential in reinforced concrete structures, considering the assumption that rebar and concrete function as composite materials. Over the years, researchers have carried out bond testing, typically using the most common types of specimens, which are cube and cylinder specimens. Despite these advancements, an observation reveals the absence of studies exploring the effect of specimen shape on bond strength. Therefore, this study attempts to investigate the influence of specimen shape on the bond strength between rebar and normal concrete. The experimental work involves the preparation of cube pullout specimens measuring 200 mm x 200 mm x 200 mm, embedded with 16 mm and 20 mm rebars. The cube pullout specimens were then subjected to direct pullout testing using the RILEM pullout test standard. Subsequently, comparisons were made with previous experimental results employing cylindrical pullout specimens (100 mm diameter x 200 mm height), which were obtained by another researcher. The bond strength analysis uses normalised bond strength to minimise the effect of variations in concrete compressive strength. The results of the analysis indicate that bond strength is affected by the thickness of the concrete cover, which is influenced by the shape of the specimens
Performance Assessment of Integrated Water Quality Monitoring Device with IoT Technology for Water Quality Monitoring
Full text linkA continuous water supply is a vital resource for domestic use and environmental sustainability, necessitating effective water management. Frequent water quality disruptions caused by river contamination have harmed aquatic life and led to shutdowns of water treatment plants, affecting consumers. The implementation of continuous online monitoring can facilitate early detection of contamination. The research focuses on the performance assessment of an integrated online water quality monitoring (IWQM) prototype (named Kolora meter) assisted with Internet of Things (IoT) technology. The IWQM prototype features seven water quality sensors, namely pH, dissolved oxygen (DO), conductivity (EC), total dissolved solids (TDS), temperature (T), turbidity (TUR), and volatile organic compound (VOC) gas, to monitor surface water. Additionally, the IWQM prototype was equipped with a mobile application, which was developed on the Blynk IoT platform. This enables the user to monitor wirelessly via smartphone or computer. This prototype was deployed and tested at Putrajaya Lake (Point 1) and Wetland (Point 2) for one month to determine its efficiency and reliability. The issues experienced during the field deployment period were identified. The data measured by the IWQM prototype was compared and validated using the data collected from a Horiba Multiparameter. The T sensor showed consistent readings with high accuracy (~0 to ~7%) while pH and DO showed inconsistent readings and accuracy. Unfortunately, the TDS, TUR, and EC could not be measured during the field deployment test due to sensor and hardware failures. The issues and mitigation strategies of the IWQM prototype have been discussed and highlighted for future improvement in the development of online water quality monitoring devices
Sustainable Water Quality Improvement in Small-Scale Tilapia Ponds Through Bio-DHS Filtration
Full text linkThis study investigates the performance of Bio-Downflow Hanging Sponge (Bio-DHS) filtration in improving water quality for small-scale Tilapia aquaculture, addressing sustainability and resource efficiency challenges. The Bio-DHS system introduces a zero-exchange water management approach, eliminating the need for water replacement by only adding small amounts to compensate for evaporation and sampling losses. This method aligns with SDG 12 (Responsible Consumption and Production) by promoting efficient water use and minimizing waste discharge. Results revealed progressive improvements in water quality, including reductions in Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), and Chemical Oxygen Demand (COD). Dissolved Oxygen (DO) levels increased to 7.00 mg/L during full-capacity operation, while nitrification efficiency reached 41.66%, indicating effective nitrogen cycling. The Water Quality Index (WQI) improved from 54.31 (polluted, Class III) without filtration to 68.20 (slightly polluted, Class III) with Bio-DHS filtration. While Class III water is suitable for aquaculture, fishery and livestock drinking, further optimization—such as extending Bio-DHS contact duration—could enhance quality for broader applications. By reducing pollutant loads in aquaculture, this system also supports SDG 14 (Life Below Water) by mitigating environmental impact and promoting cleaner water bodies. The Bio-DHS system is scalable and adaptable, making small-scale Tilapia fish ponds a viable, cost-effective solution for sustainable aquaculture in Malaysia. Future research should focus on optimizing microbial development and operational parameters to achieve higher WQI classifications
Post-Thermal Performance of Concrete Containing 60% of Slag
Full text linkPost-thermal performances of concrete have been studied extensively, as it is crucial to determine whether the structure can be used after a fire event; however, concrete properties can always be improved. One of the innovations introduced in concrete mixtures is the replacement of cement with industrial waste materials, such as slag. Concrete containing slag is already established in the construction industry. However, there is limited information regarding the post-thermal performance of concrete containing slag up to a 60% replacement. Hence, this study aims to investigate the post-thermal performance of concrete containing 60% slag replacement at ambient temperature and after exposure to elevated temperatures of 200°C and 500°C for one hour. Therefore, the properties of hardened concrete were determined. Three batches of 100 mm ´ 100 mm ´ 100 mm cubes specimens containing 0% (normal concrete, NC) and 60% slag replacement (concrete containing slag, CCS) were tested under compressive strength test. It was found that the compressive strength of CCS is 34.4 MPa, which is lower than that of NC, which achieved 40.6 MPa with 0.85 difference ratio. The residual compressive strength of CCS is 32.6 MPa, while NC has 47.4 MPa, with 0.69 difference ratio. The residual compressive strength decreases gradually with an increasing temperature exposure up to 500°C. A similar trend also occurs on modulus of elasticity (MOE); CCS has a decrease of elastic modulus compared to NC. In contrast for 200°C temperature exposure, CCS shows an increment about 19 on MOE value. However, both NC and CCS maintain a residual compressive strength exceeding 30 MPa, which remains within the acceptable target range. It can be concluded that slag can give an acceptable potential for the future in construction industry.
Electromagnetic Simulation of Metamaterial Lens Antenna with Negative Refractive Index at 28GHz
Full text linkLens 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
Macrostructural Performance of Binary Blend Self-Compacting Concrete (SCC) Containing Calcined Eggshell and Silica Fume Exposed to Elevated Temperature
Full text linkConcrete, as a main material in the construction sector, has been essential for global advancement. Traditional cement production, a crucial component of concrete, contributes significantly to environmental challenges, particularly CO₂ emissions, which are a major concern in efforts to mitigate climate change. In addition, typical concrete frequently presents issues such as low workability and poor performance during handling and placing. While advancement has been made by combining sustainable resources, the potential for self-compacting concrete (SCC) using Calcined Eggshell Powder (CESP) and silica fume (SF) as a sustainable alternative remains underexplored. The present study addresses the urgent demand for environmentally friendly and high-performance concrete by assessing the fresh and macrostructural properties of SCC with CESP and silica fume (SF) as partial cement substitutes, particularly at elevated temperatures. Fresh properties tests, such as Slump Flow, T500, and Sieve Segregation, were used to evaluate the flowability and stability of SCC mixes, while macrostructural properties testing was used to measured compressive and split tensile strengths. SCC mixes were produced with varying CESP content (0%, 5%, 10%, and 15%) and 10% SF as partial cement replacements. Compressive strength was evaluated using 100x100x100 mm cubes, whereas split tensile strength was determined utilizing 50 mm diameter × 100 mm height cylinders. The experimental results revealed that all SCC combinations met or exceeded the EFNARC 2005 criteria for flowability and segregation resistance, with slump flow values that varied between 555–660 mm (EFNARC limit: 550–850 mm), T500 times between 3.56–5.82 seconds (EFNARC range: 3–6 seconds), and sieve segregation ratio of 5.67–11 % (EFNARC limit: ≤15 %). The compressive and split tensile strengths met critical threshold of 30 MPa and 2 MPa, respectively, confirming the practicality of the proposed mix designs. Additionally, the CE5S10 mix achieved optimal performance with compressive and split tensile strengths of 28.24 MPa and 2.67 MPa, respectively. Failure modes exhibited diverse fracture patterns, including edge cracks in compressive samples and horizontal center cracks in tensile specimens. A linear relationship was discovered between compressive and split tensile strengths, implying a forecasting potential for material performance. The study\u27s findings emphasize the innovative potential of incorporating calcined eggshell powder and silica fume into SCC, which provides an additional benefit of lowering the usage of cement while also reusing waste materials. This research not only adds to the development of more sustainable construction practices, but it also fills crucial gaps in understanding the performance of sustainable concrete at elevated temperatures. The findings lead to a path for widespread adoption of eco-friendly SCC formulations, which aligns with global initiatives to reduce environmental impacts and promote principles of the circular economy in the construction sector
Microstrip Patch Antenna Design for Natural Rubber Permittivity Detection
Full text linkThis paper presents a simulation-based analysis on a rectangular microstrip patch antenna sensor capable of detecting changes in natural rubber (NR) permittivity using CST Microwave Studio. In this work, the patch antenna sensor was designed with a gap distance of 1.0 mm, 1.5 mm, and 2.0 mm between the patch and the feeder, which affects the resonance characteristics of the antenna and enhances the interaction between its radiated waves and the NR, which is the Material Under Test (MUT). As the dielectric properties were disposed of between 2.7 to 4.8 according to the experimental observable (using vector network analyzer (VNA) and dielectric probe) for NR samples in simulation model. This could be helpful in designing to see how the gap distance affects the resonant frequency shift of the antenna, return loss, and sensitivity. The 2.0 mm gap configuration in this study has the highest sensitivity of -0.0072 GHz/ε with the linear measurement rate of 0.9979, which is more sensitive to the changes of dielectric. Therefore, these results verify the capability of the microstrip patch antenna sensor for precise and dependable permittivity detection in agriculture applications
3D Printed Tuneable Silicone Foams via Direct Templating Approach
Full text linkSilicone is well-known for its appealing properties like high elasticity, hydrophobicity and biocompatibility, which translates to diverse applications including silicone foams. However, current foaming methods are complex, lengthy and involves hazardous chemicals. The direct templating approach tackles these complications by saturating the silicone precursors with sacrificial templates, e.g. salts or sugar crystals. These templates are leached out in appropriate solvents after vulcanization, leaving behind porous structures. The resulting pores and mechanical properties of the foams can be tuned by varying the quantity of sacrificial templates introduced. In addition, 3D printed architectures present greater degree of complexity for said silicone foams. Herein, facile silicone foams with tuneable properties are fabricated via Direct Ink Writing (DIW) with the inclusion of glucose sugar crystals into a one-part room temperature vulcanizing (RTV-1) silicone formulation, with deionized water as the eco-friendly solvent. The silicone ink formulations were proven to fulfil viscoelastic requirements of DIW. Pore morphologies of formulated foams with varied glucose content of 15 phr to 55 phr were characterized by SEM. The results showed presence of macropores with pore sizes ranging from 26.44 µm to 52.39 µm and porosity ranging from 15.03 % to 31.60 %. The pore size and porosity of the foam samples were found to be linearly proportional to the amount of glucose content. Tensile tests unveiled that with increasing sugar content, mechanical properties of said foams had been varied with tensile strength (0.96 – 0.59 MPa), elongation at break (511 - 362 %), and Young’s modulus (0.50 - 0.37 MPa). The foams also displayed decreasing Shore A hardness (35.8 – 30.1) as porosity increased. This simplistic approach represents a feasible method of creating silicone foams with tuneable properties using easily attainable and safe materials.