Leakage Detection in Pipeline using Wavelet Transform Method

This research project is focusing on the leakage detection in the pipelines using wavelet and cepstrum analysis. To fully complete this research project, experimental and analysis by using signal processing are required. This research project proposed a technique which is a transient method. The basic principle is the fact that water spouting out of a leak in a pressurized pipe generates a signal, and this signal contains information to whether a leak exists and where it is located. The present transient methods for finding leaks are mainly based upon correlation analysis, where one sensing device is installed at each side of a leak. This method is hard to operate because it needs many operators to operate it due to equipment in different place. This research project proposed a wavelet transform method to detect leakage in the pipeline system. The experimental results show appears  to improve the ability of the method to identify features in the signal

Detection of irregularities on weld bead from the L-Statistic analysis of the acquired sound during pulse mode laser welding process

Since several past decades, many studies prove that the statistical or signal features extracted from the sound acquired from laser welding process was significantly giving information on the weld condition. However, a considerable amount of studies were only emphasizing on the use of common statistical features in which it is restricted to some limitation when dealing with non-stationary random sound signal. In this particular work, the main aim was set to detect the irregularities along the weld bead by way of implementing the L-Statistic analysis on the acquired sound during pulse mode laser welding process. To achieve the goal, pulse mode laser welding have been done onto 22MnB5 boron steel plate in butt joined configuration. During the process, sound signal was acquired using microphone and further analyzed by extracting L-statistic features from it. According to the findings, among all the L-statistic features analyze in this study, L-Cv (scale) was found giving a significant indicator of the weld bead surface condition. Larger value of L-Cv was recorded at the point where the large underfill occurred. On the other hand, it was also found that the L-kurtosis values could give remarkable information on the existence of the irregularities on bead width and depth. Hence, it could be drawn into conclusion that the irregularities on the weld bead during the pulse mode laser welding could be detected from the appropriate L-statistic features of the acquired sound signal. The finding in this work was believed to be essential in enhancing the capability of acoustic sound method to be developed as online monitoring system for pulse mode laser welding process

Advancements in phase change materials for energy-efficient building construction: A comprehensive review

The building sector, representing a significant share of energy consumption, accounts for 60 % of energy consumption, particularly in Heating, Ventilation, and air conditioning (HVAC). Phase change materials (PCMs), distinguished by their ability to store and release substantial heat in response to ambient temperature changes, emerge as promising solutions for integrating thermal regulation technologies in building design. While literature showcases studies demonstrating the incorporation of PCMs into various building materials, there is a dearth of comprehensive reviews covering their integration into building components. This study classifies PCMs based on material composition and the nature of phase change, presenting a brief overview to highlight their diverse applications in the thermal regulation of buildings. Further, it summarizes various studies on PCM incorporation in building materials such as roofs, walls, cement, bricks, paints, floors, and windows, bridging the gap in existing research. Solid-liquid organic PCMs are widely researched compared to inorganic and solid-solid PCMs for building applications. Solid-liquid PCMs require containment for liquid state handling during phase changes, mainly applied in encapsulated forms. Building components such as bricks and floors can incorporate PCMs in any encapsulated form. Based on the Review findings, adding PCM to cement plaster often reduces mechanical properties and increases cement porosity, impacting the hydration process, except when using dopamine-coated cenosphere PCM capsules. Phase change paints, primarily utilizing micro/nano encapsulated PCMs, reveal varying effects on paint properties based on the percentage of PCM capsules added, with peak temperature reductions of 1–6 °C observed in building applications. Solid-solid PCMs are primarily applied in windows, where PCM-filled glazed windows significantly reduce peak temperatures up to 9 °C. Reduction in peak temperatures from 1 °C–7 °C and heat loads by 19–59 % were observed for PCM integrated in Roof. South-faced walls equipped with PCM layers exhibit superior thermal performance compared to other orientations. In conclusion, this review consolidates recent advancements and provides valuable insights into PCM applications in various building components, serving as a valuable resource for researchers, engineers, and industrial experts

Performance optimization of automotive air-conditioning system operating with al2o3-sio2/pag composite nanolubricants using taguchi method

The performance of an automotive air-conditioning (AAC) system is influenced by a variety of operating conditions. This can be addressed by employing optimization techniques that can suggest the appropriate parameters for the best results. In this study, the optimum operating conditions for a composite nanolubricants-fuelled AAC system were investigate using Taguchi's design of experiment approach and analysis of variance (ANOVA). The motor speed value, initial refrigerant charge, and composite nanolubricants composition ratio were chosen as operating parameters to investigate the AAC system performance, focusing on the coefficient of performance (COP) and compressor work. Orthogonal arrays (ORs) L25 (56) was selected to determine the optimum operating parameters of the AAC system. The optimum values for speed, refrigerant mass, and composition ratio were determined to be A4B1C5 (60:40, 900 rpm and 155 g), respectively. The motor speed was the significant factor influencing both COP and compressor performance by 78.13% and 89.29%. A confirmation test was conducted with the optimum levels of AAC system parameters to verify the efficiency of the Taguchi optimization method. The validation between the optimization results and the experimental results yielded a maximum error of 9.85%, indicating that the findings of this investigation were acceptable

Viscosity and friction reduction of double end capped polyalkylene glycol nanolubricants for eco friendly refrigerant

In sustainable tribology, researchers are investigating methods to enhance tribological performance by incorporating nanoparticles into lubricants. However, one potential drawback of this strategy is increased lubricant viscosity. The current study aimed to assess the impact of these nanoparticles on the viscosity and coefficient of friction (COF) of the nanolubricants. Three different nanolubricants were synthesized through a two-step process, including mono-nanolubricants (Al2O3/DEC PAG and SiO2/DEC PAG) and hybrid nanolubricants (Al2O3-SiO2/DEC PAG), at volume concentrations between 0.01% and 0.05%. The viscosity and shear flow behavior of these nanolubricants were evaluated using a digital rheometer, while the COF was measured using a Koehler four-ball tribometer. All the nanolubricants showed Newtonian behavior during the experiments. The dynamic viscosity velocity increment of SiO2/DEC PAG was found to be the lowest (1.88%), followed by Al2O3-SiO2/DEC PAG (2.74%) and Al2O3/DEC PAG (3.56%). The viscosity indices of all the nanolubricants were improved only at higher concentrations. At a volume concentration of 0.03%, the Al2O3-SiO2/DEC PAG nanolubricant reduced the COF by up to 8.1%. The results showed that the combination of nanoparticles, temperature, and volume concentration significantly influenced the viscosity and COF of nanolubricants. This study provides essential information for developing high-performance nanolubricants with improved viscosity and COF and advancing environmentally friendly tribology solutions

Pathway to Sustainability: An Overview of Renewable Energy Integration in Building Systems

Decarbonizing the building sector is crucial for mitigating climate change, reducing carbon emissions, and achieving an energy production–consumption balance. This research aims to identify key design principles and strategies to enhance energy savings and analyze the integration potential of renewable energy sources (RES) such as solar, wind, geothermal, and biomass, providing in-depth technical exploration and evaluating current building developments. Moreover, the study also examines recent developments, explicitly focusing on integrating hybrid renewable energy systems, energy storage solutions, and AI-based technological innovations. Through comprehensive analysis and critical evaluation, this research provides valuable insights and practical recommendations for achieving building sustainability and advancing the transition towards a low-carbon built environment

Stability and thermal conductivity of mono and hybrid nanoparticles dispersion in double-end capped pag lubricant

Stable nanolubricant mixtures are interrelated with thermal conductivity enhancement, thus improving heat transfer performance in automotive air conditioning (AAC) systems. This paper studies the stability and thermal conductivity of double-end capped polyalkylene glycol (PAG)-based nanolubricants specially designed for R1234yf refrigerant. Mono nanolubricants (Al2O3/PAG and SiO2/PAG) and hybrid nanolubricants (Al2O3–SiO2/PAG) were prepared using a two-step preparation method at different volume concentrations of 0.01 to 0.05%. The stability of these nanolubricants was observed by visual, UV-Vis spectrophotometer, and zeta potential. Thermal conductivity (k) was measured from 30 to 70 °C using a C-Therm thermal properties analyser. The results from the stability analysis show that all nanolubricants were confirmed in excellent stability conditions for more than six months with minimum visual sedimentation, more than 70% concentration ratio, and zeta potentials greater than 60 mV. The Al2O3–SiO2/PAG samples recorded the highest values of thermal conductivity increment, followed by the Al2O3/PAG and SiO2/PAG samples with 2.0%, 1.7%, and 1.5% enhancement. Hybrid nanolubricants have been shown to have greater potential in the AAC system because of their excellent stability and better property enhancement in thermal conductivity

Performance enhancement and optimization of residential air conditioning system in response to the novel FAl2O3-POE nanolubricant adoption

This paper aims to evaluate residential air conditioning systems' performance enhancement and optimization by adopting a novel functionalized Al2O3 (FAl2O3)–Polyolester (POE) nanolubricant. Comprehensive discussions were conducted on key performance parameters, including heat absorption, compressor work, cooling capacity, coefficient of performance (COP), and power consumption. Novel FAl2O3 nanoparticles were dispersed into the POE lubricant using a two-step method. The findings reveal that FAl2O3–POE nanolubricant exhibits superior heat absorption compared to pure POE. Heat absorption decreases with an increased initial refrigerant charge, while cooling capacity performance improves with an increased initial refrigerant charge. The COP shows an increasing trend at all concentrations of FAl2O3–POE nanolubricant when operating with R32. FAl2O3–POE/R32 demonstrates an enhanced range of 3.12%–32.26% for COP. The results suggest that applying novel FAl2O3–POE nanolubricant with R32 can reduce electrical power consumption by 13.79%–19.35%. The central composite design (CCD) offers an optimal condition for FAl2O3–POE nanolubricant with a concentration of 0.11 vol%, an initial refrigerant charge of 0.442 kg, resulting in a COP of 3.982, a standard error of 0.019, and a desirability of 1.0

CFD-study of the H-Rotor Darrius wind turbine performance in drag-lift and lift regime : Impact of type, thickness and chord length of blades

The high power coefficient of the Darrius vertical axis wind turbine lift regime has prompted researchers to concentrate their efforts on this regime, despite the fact that these turbines suffer from major problems in the drag-lift regime. In the present study, in addition to exploring the performance of the Darrius type wind turbine at blade tip speeds Ratio above 1, the effect of design factors on its performance at TSRs below 1 is also investigated. The results were extracted from numerical analysis recruiting Fluent software and the k-w SST turbulence model. The effect of blade type, thickness, and chord length on turbine performance has been investigated. The blade angle of attack (AOA) at TSR less than one was calculated using a new equation, and the results were evaluated. The numerical study of the Darrius wind turbine showed that increasing the chord length for symmetric and asymmetric airfoils from 0.1 to 0.2 m enhances the turbine performance in drag-lift regime, whereas decreasing chord length improves turbine performance at higher TSRs. The blade with a curvature of 4 % and a chord length of 0.1 m has the best performance at TSR 2.25. Increasing the thickness from 18 to 22 % of chord length exerts a negative influence on the turbine's performance in both regimes, and at lower TSRs, NACA0018 airfoil with a chord length of 0.2 m was of the optimum performance in the drag-lift regime

Spectral subtraction-based filter for experimental modal analysis under harmonics excitation force

In modal analysis, measurement of input force and vibration response are crucial to accurately measure the transfer function of the structure. However, under operating condition, the force induced by operating machinery is impossible to be measured due to the sensor placement issue. In this case, the ambient response induced by the operating force should be suppressed to minimize the error in the Frequency Response Function (FRF) calculation. This paper presents the utilization of a modified spectral subtraction filter for ambient suppression. The introduction of effective ambient magnitude in gain function calculation has increased the efficiency of spectral subtraction filter. This parameter is calculated based on the phase information of the reconstructed artificial ambient response. The measurement using EMA was carried out on a motor-driven structure to verify the proposed technique. Two sets of data under shutdown and running condition were recorded to observe the effect of ambient operating force. Under the operating condition, the measured FRF show the non-identical features at operating frequencies as compared to the baseline data. The utilization of filtering process shows the ambient features contained in the transfer function was effectively suppressed. The output of filtering algorithm could provide an alternative option to perform EMA procedure under running condition