SOURCE: Diagnostics

AUTHOR: TAN XIAO JIAN (Main Author) 

RESEARCH CENTRE: CMSP

SDG: 3,9

CITATION: Tan, X.J.; Cheor, W.L.; Lim, L.L.; Ab Rahman, K.S.; Bakrin, I.H. Artificial Intelligence (AI) in Breast Imaging: A Scientometric Umbrella Review. Diagnostics 2022, 12, 3111. https://doi.org/10.3390/diagnostics12123111

ABSTRACT: Artificial intelligence (AI), a rousing advancement disrupting a wide spectrum of applications with remarkable betterment, has continued to gain momentum over the past decades. Within breast imaging, AI, especially machine learning and deep learning, honed with unlimited cross-data/case referencing, has found great utility encompassing four facets: screening and detection, diagnosis, disease monitoring, and data management as a whole. Over the years, breast cancer has been the apex of the cancer cumulative risk ranking for women across the six continents, existing in variegated forms and offering a complicated context in medical decisions. Realizing the ever-increasing demand for quality healthcare, contemporary AI has been envisioned to make great strides in clinical data management and perception, with the capability to detect indeterminate significance, predict prognostication, and correlate available data into a meaningful clinical endpoint. Here, the authors captured the review works over the past decades, focusing on AI in breast imaging, and systematized the included works into one usable document, which is termed an umbrella review. The present study aims to provide a panoramic view of how AI is poised to enhance breast imaging procedures. Evidence-based scientometric analysis was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline, resulting in 71 included review works. This study aims to synthesize, collate, and correlate the included review works, thereby identifying the patterns, trends, quality, and types of the included works, captured by the structured search strategy. The present study is intended to serve as a “one-stop center” synthesis and provide a holistic bird’s eye view to readers, ranging from newcomers to existing researchers and relevant stakeholders, on the topic of interest.

SOURCE: IEEE ACCESS

AUTHOR: TAN XIAO JIAN (Co-Author) 

RESEARCH CENTRE: CMSP

SDG: 9

CITATION: S. Y. Yip, D. W. Yong, K. H. Yiauw, X. J. Tan and J. Y. R. Wong, "Model Predictive Direct Torque With Fault Tolerance Control for a Permanent Magnet Synchronous Generator Based on Vienna Rectifier," in IEEE Access, vol. 10, pp. 94998-95007, 2022, doi: 10.1109/ACCESS.2022.3204809. 

ABSTRACT: This paper presents the fault tolerance of model predictive direct torque control for a permanent magnet synchronous generator under a faulty Vienna rectifier. The fault applied includes open-switch and short-switch fault in a particular active switching device of the Vienna rectifier. The measured input current is used in the proposed fault diagnosis approach to detect the switch fault’s position without any additional hardware being implemented. Whenever a switching fault occurs at any phase of the Vienna rectifier, the available switching vectors for prediction control are reduced from five to four. The feasibility and effectiveness of the proposed fault tolerance model predictive direct torque control under a faulty Vienna rectifier are demonstrated and investigated through MATLAB/Simulink. The results show that it is feasible for the proposed method to be operated under a short-switch fault with slightly higher total harmonics distortion of the input current but out of control under an open-switch fault.

SOURCE: IIUM Engineering Journal

AUTHOR: NG CHUI KIM (Main Author) 

RESEARCH CENTRE: CAM

SDG: 3,12,9

CITATION: Ng, C. K., Lee, S. K. Y., Tan, C. H., Singh, R., Ting, C. H. ., Chuah, Y. D., Tan, C. Y. ., & SUTHARSINI, . U. (2022). Characterization and Sintering Properties of Hydroxyapatite Bioceramics Synthesized From Clamshell Biowaste. IIUM Engineering Journal, 23(2), 228–236. https://doi.org/10.31436/iiumej.v23i2.2143 

ABSTRACT:

Hydroxyapatite (HA) is a type of calcium phosphate-based bioactive ceramic that resembles the mineral phase of bone and teeth with great potential for bone substitution and biomedical implants. Biogenic-derived HA emerges as a cheap and eco-sustainable alternative to improve waste utilization. However, hydroxyapatite has limited applications due to its apparent brittleness, thus prompting investigation for enhanced sintering properties.  In the present study, the combination of calcination and chemical precipitation technique was used to extract hydroxyapatite (HA) from ark clamshells (Anadara granosa). The method successfully produced HA powder with a Ca/P ratio of 1.6 and characteristic bands corresponded to pure HA via Fourier Transform Infrared Spectroscopy (FTIR). The synthesized HA powder was then sintered at temperatures ranging from 1200 °C to 1300 °C, followed by mechanical evaluation of the density, Vickers hardness, fracture toughness and grain size. It was revealed that the samples sintered at 1250 °C achieved a relative density of ~88%, Vickers hardness of 5.01 ± 0.39 GPa, fracture toughness of 0.88 ± 0.07 MPa.m1/2 and average grain size of ~3.7 µm. Overall, the results suggest that ark clamshell synthesized HA (ACS) had the potential to be used as functional bioceramics for biomedical applications.

SOURCE: Materials Science Forum

AUTHOR: HO MUI YEN (Main Author) 

RESEARCH CENTRE: CAM

SDG: 7,9

CITATION: Yao, G. T. S., Yen, H. M., Lun, L. K., Wei, O., & Xiang, L. J. (2022). Synthesis of Graphene/Silver/Molybdenum Disulphide Composite for Supercapacitor Application. In Materials Science Forum (Vol. 1054, pp. 21–30). Trans Tech Publications, Ltd. https://doi.org/10.4028/p-u48e5d

ABSTRACT:

In this study, pristine graphene/silver/molybdenum disulphide (G/Ag/MoS2) and reduced graphene oxide/silver/molybdenum disulphide (rGO/Ag/MoS2) composites materials were prepared via green solvothermal synthesis method and evaluated as supercapacitor electrodes. The morphology and structure of composites were examined by using Scanning Electron Microscopy (SEM), Energy dispersive spectroscopy (EDX), X-ray diffraction spectroscopy (XRD), and Raman spectroscopy. SEM and TEM indicate successful reduction of silver nitrate (AgNO3) to spherical Ag nanoparticles (NPs) by sodium citrate. The Ag NPs were observed to be evenly deposited on sheets of rGO and MoS2. From the XPS analysis, the spherical Ag NPs exist in zero-valent state, reflecting successful reduction. Based on cyclic voltammetry (CV) performed under 50 mV/s scan rate, G/Ag/MoS2 ternary composite exhibits the highest specific capacitance of 56.38 F/g which is 31 % and 29 % enhancement in specific capacitance of rGO/Ag/MoS2 ternary composite and Ag/MoS2 binary composite, respectively. It is believed that the presence of graphene may provide conductive pathway and a larger surface area for the distribution of Ag NPs.

SOURCE: International Journal of Nanoelectronics and Materials

AUTHOR: YIP MUM WAI (Co-Author) 

RESEARCH CENTRE: CSIR

SDG: 9

CITATION:  Chua, H. (2022). Simulation, prototyping and testing of a new gripper design to automate double chlorination of rubber gloves. Universiti Malaysia Perlis (UniMAP). (Link)

ABSTRACT:

Chlorination improves rubber gloves donnability. Production of single-chlorinated gloves is fully automated. Double-chlorinated gloves are needed for medical applications. These gloves are chlorinated on both internal and external surfaces. Double-chlorinated gloves are produced with second chlorination. Gloves after the earlier chlorination were manually immersed into another chlorine tank. This manual process endangers the workers and is time-consuming. A gripper was designed to integrate double chlorination to be fully online. The gripper grasps the glove after first chlorination to proceed to second chlorine tank. The gripper has a solid stainless steel body and flexible rubber seal. It is applicable to different glove sizes, chlorine resistant, leakage proof, and heat resistant. Engineering analysis was conducted through simulation and experimental testing. Simulation results showed the solid body does not yield under load. Simulation results also showed the gripper does not experience fatigue damage after multiple working cycles. A prototype was built for experimental testing. Experimental results proved that gripper is heat resistant, grasps all glove sizes, and no seepage indication under water for all glove samples. It was concluded that the gripper justifies for a full trial production run. The project contributes to improved worker safety and productivity, leading to lower production cost.

SOURCE: Journal of Ceramic Processing Research

AUTHOR: SARA LEE KIT YEE (Co-Author)            

RESEARCH CENTRE: FOET

SDG: 3,12,9

CITATION: K.W. Goh, Y.H. Wong, R.S.K. Singh, Hari Chandran, S.K. Wong and K.Y. Sara Lee. (2022). Irradiation time-dependent study of eggshell-derived hydroxyapatite powder synthesized by microwave-assisted wet chemical precipitation method. Journal of Ceramic Processing Research, 23(2), 158-164. Link

ABSTRACT:

The extraction of calcium from natural biowaste material such as chicken eggshells have been shown to be viable to synthesis calcium phosphate bio ceramic. In this work, eggshell-derived hydroxyapatite powder was synthesised by using the wet chemical precipitation technique coupled with microwave irradiation at low power (700 W) at varying exposure time from 5to 30 min. The derived nano-powders were examined to determine the phases present, chemical bonding and micro structural evolution. It was revealed that the irradiation time has an effect on the degree of crystallinity and both the crystallite and particle size of the derived powders although the hydroxyapatite phase stability was not disrupted. An exposure time of 15 min. was determined to be sufficient when subjected to low power microwave irradiation to formed a well-defined needle-like hydroxyapatite particles having an average crystallite size of about 22 nm. On the contrary to many literatures, this study has demonstrated the viability of synthesizing a useful bioceramic from using biowaste eggshells coupled with microwave irradiation at low power of 700 W for very short period of time to produce nano-range needle-like hydroxyapatite particles suitable for biomedical application.

SOURCE: MDPI sensors

AUTHOR: GOH KAM MENG (Co-Author) 

RESEARCH CENTRE: CMSP

SDG: 9

CITATION: Cheng, X.; Chaw, J.K.; Goh, K.M.; Ting, T.T.; Sahrani, S.; Ahmad, M.N.; Abdul Kadir, R.; Ang, M.C. Systematic Literature Review on Visual Analytics of Predictive Maintenance in the Manufacturing Industry. Sensors 2022, 22, 6321. https://doi.org/10.3390/s22176321 link

ABSTRACT:

The widespread adoption of cyber-physical systems and other cutting-edge digital technology in manufacturing industry production facilities may motivate stakeholders to embrace the idea of Industry 4.0. Some industrial companies already have different sensors installed on their machines; however, without proper analysis, the data collected is not useful. This systematic review’s main goal is to synthesize the existing evidence on the application of predictive maintenance (PdM) with visual aids and to identify the key knowledge gaps in areas including utilities, power generation, industry, and energy consumption. After a thorough search and evaluation for relevancy, 37 documents were identified. Moreover, we identified the visual analytics of PdM, including anomaly detection, planning/scheduling, exploratory data analysis (EDA), and explainable artificial intelligence (XAI). The findings revealed that anomaly detection was a major domain in PdM-related works. We conclude that most of the literature lacks depth in terms of an overall framework that combines data-driven and knowledge-driven techniques of PdM in the manufacturing industry. Some works that utilized both techniques indicated promising results, but there is insufficient research on involving maintenance personnel’s feedback in the latter stage of PdM architecture. Thus, there are still pertinent issues that need to be investigated and limitations that need to be overcome before PdM is deployed with minimal human involvement.

SOURCE: Journal of Mechanical Engineering and Sciences (JMES)

AUTHOR: TEOH CHOE YUNG (Main Author)         

RESEARCH CENTRE: CASRR

SDG: 9

CITATION: Yung, T. C., J.S. Pang, M.N. Abdul Hamid, L.E. Ooi, & W.H. Tan. (2022). Ultrasonic guided wave testing on pipeline corrosion detection using torsional T(0,1) guided waves. Journal of Mechanical Engineering and Sciences, 16(4), 9157–9166. https://doi.org/10.15282/jmes.16.4.2022.01.0725

ABSTRACT:

Ultrasonic guided wave testing (UGWT) is used in rapid screening to detect, locate and classify corrosion defects. This non-destructive testing technique can perform wide-range inspection from a single point, thus reducing the time and effort required for NDT. However, the mode conversion phenomena and the dispersive nature of the guided waves make corrosion detection difficult. Hence, the parametric studies on the response signals of a T (0, 1) wave from pipe defects were presented in this paper. Firstly, a mathematical model of 6-inch schedule 40 pipes was developed. The corrosion profile of various geometries was then constructed on the outer surface of the pipeline by varying the circumferential length and depth. The numerical study was performed to analyse the characteristics of the response signals when a torsional guided wave impinges on the corroded pipelines. A five-cycle Hanning tone-burst signal with a central frequency of 30k Hz was used throughout the study. The results demonstrated that mode conversion to a flexural mode F (1, m) occurs when the stimulated T (0, 1) strikes non-symmetric defects. Nonetheless, as the circumferential extent of the corrosion increased, the response signals tended to behave symmetrically, and there was less mode conversion detected. Thus, the presence of flexural mode F (1, m) can be used as the criteria to distinguish symmetric and asymmetric faults. In addition, the results demonstrated that the reflection coefficients increase monotonically with the defect's depth due to the increases in the estimated cross-sectional area loss (ECL). As a result, a more significant proportion of the transmission wave was reflected. These findings serve as guidelines for on-site inspections. With the known speed of guided wave propagation, it is possible to precisely forecast the position of faults.

SOURCE: Journal of King Saud University - Computer and Information Sciences

AUTHOR: TAN XIAO JIAN (Main Author) 

RESEARCH CENTRE: CMSP

SDG: 9,17

CITATION: Tan, X. J., Cheor, W. L., Yeo, K. S., & Leow, W. Z. (2022). Expert systems in oil palm precision agriculture: A decade systematic review. Journal of King Saud University-Computer and Information Sciences, 34(4), 1569-1594. (link)

ABSTRACT:

Oil palm (Elaeis guineensis Jacq.) is of the most profitable and widespread commercial high tree crops in the tropical world, typically in Southeastern Asia. The present study aims to provide a brief but broad overview of different applications of expert systems (ESs) in oil palm precision agriculture (PA), focusing on the three main generic categories: crop, water, and soil management. This study is meant to review research articles from the past decade: 2011–2020. Based on the search strategy alongside the inclusion criteria, 108 articles were included for synthesis activity. The findings of the study reveal patterns, networks, relationships, and trends in the application of ESs in oil palm PA in the past decade. The broad insight obtained from the synthesis activity was used to identify the possible roads ahead in oil palm PA. The findings of this study could be useful and beneficial to the research community and stakeholders in identifying the progress and trends of ESs in oil palm PA in the past decade, help to gain a holistic view on research gaps, potential markets, relevant advantages, the roads ahead, and contributing to further systematic research (deepen or broaden) in this topic.

SOURCE: Journal of Mechanical Engineering (JMechE)

AUTHOR: TEOH CHOE YUNG (Co-Author) 

RESEARCH CENTRE: CASRR

SDG: 9

CITATION: Cong Ho, Z., & Teoh, C. (2022). Modal Analysis of Delaminated Flax Fibre Reinforced Epoxy Composite Plate. Journal Of Mechanical Engineering (JMechE), 19(3), 135-153. doi:10.24191/jmeche.v19i3.19800 link

ABSTRACT:

This paper describes the influence of fibre orientation, delamination size and location on the natural frequencies of the single mid-plane delaminated unidirectional flax fibre reinforced epoxy (FFRE) composite plates under different boundary conditions numerically by using ANSYS MAPDL. The delaminated composite plate was modelled as two separate volumes divided at the midplane of the plate, with the nodes on the intact surfaces merged. In contrast, the nodes on the delaminated region remained separate. The results show that the CCCC delaminated composite plate has the highest fundamental natural frequency (219.996 Hz). Furthermore, for increasing fibre orientation from 0 to 45, the fundamental natural frequencies decreased by 10.12% for the CCCC condition and increased by 6.01% for the SSSS condition. The fundamental natural frequency for the cantilever condition decreased 60.91% when fibre orientation increased to 90. Moreover, the CCCC condition significantly reduces the fundamental natural frequency (up to 38.95%) with increasing delamination size. For CCCC and SSSS conditions, the centre delamination possesses the highest fundamental natural frequency (219.996 Hz and 116.525 Hz, respectively). The highest fundamental natural frequency for cantilever conditions is 33.081 Hz, with delamination located at the middle of the width and near the free end.

SOURCE: Materials Today: Proceedings

AUTHOR: SARA LEE KIT YEE (Main Author)         

RESEARCH CENTRE: FOET

SDG: 3,12

CITATION: Lee, KY Sara, et al. "Low-temperature degradation behaviour of microwave sintered CuO-doped Y-TZP ceramics." Materials Today: Proceedings 66 (2022): 2791-2795. here

ABSTRACT:

The low-temperature degradation (LTD) behaviour of undoped and 0.2 % copper oxide-doped 3 mol% yttria-tetragonal zirconia polycrystal (Y-TZP) via microwave (MWV) sintering were studied in this work. The MWV-sintered samples were heated at temperatures varying from 1100 to 1400 °C, with a heating rate of 30 °C per min and holding time of 5 min. These samples were then assessed and compared with the conventional (CV) sintered samples that were executed at the ramp rate of 10 °C per min. The MWV and CV-sintered Y-TZPs were aged in an autoclave vessel and kept in an oven at 180 °C/10 bar up at different intervals, up to 200 h. The results show no substantial difference in the microstructure or grain size between MWV and CV-sintered samples at above 1250 °C. In addition, there was no monoclinic phase detected from the X-ray diffraction (XRD) for both undoped and doped Y-TZPs after ageing for 200 h, regardless of sintering methods, with sintering temperature up to 1400 °C. It was revealed that Y-TZPs with a grain size smaller than 0.28 μm were resistant to hydrothermal ageing. The study also indicated that the beneficial effect of microwave diminished when samples were sintered at elevated temperatures.

SOURCE: Multimedia Tools and Applications

AUTHOR: TAN XIAO JIAN (Main Author)         

RESEARCH CENTRE: CMSP

SDG: 3, 9

CITATION: Tan, X. J., Mustafa, N., Mashor, M. Y., & Ab Rahman, K. S. (2021). Spatial neighborhood intensity constraint (SNIC) clustering framework for tumor region in breast histopathology images. Link

ABSTRACT:

Precise segmentation of tumor regions plays prominent role in the grading of breast carcinoma using the Nottingham Histological Grading (NHG) system. A robust segmentation framework is expected to produce cost-effective, repeatable, and reproducible quantitative outputs. In this study, a spatial neighborhood intensity constraint (SNIC) clustering framework for tumor region in breast histopathology images is presented. The proposed framework consists of five main stages:(1) color normalization,(2) segmentation and removal of nucleus cells,(3) SNIC,(4) FCM with knowledge-based initial centroids selection, and (5) post-processing. The novelty of the proposed framework lies within its simple but powerful in clustering tumor regions precisely in a heterogenous environment. The SNIC is implemented to remove and replace the intensity of the nucleus cells based on the spatial constraints. Also, a knowledge-based initial centroids selection method is implemented to ease the FCM clustering algorithm. Both of these methods are posited to facilitate the clustering stage producing complementary results. To validate the hypothesis, careful justifications are performed to evaluate the role of SNIC and knowledge-based initial centroids selection. These methods are found plausible by achieving positive results in\(Acc\),\(F1\),\(AOM\), and\(CEI\) of 91.2%, 92.1%, 85.7%, and 90.1%, respectively. To further demonstrate the applicability of the proposed framework, four recent works are included for benchmarking purposes. The proposed framework found outperformed these methods with the lowest percentages in over-segmentation and under-segmentation: 8.7% and 6.6%, respectively.

SOURCE: Alexandria Engineering Journal

AUTHOR: LIM LI LI (Co-Author) 

RESEARCH CENTRE: CMSP

SDG: 9

CITATION: Geok, T. K., Hossain, F., Rahim, S. K. A., Elijah, O., Eteng, A. A., Loh, C. T., ... & Hindia, M. N. (2022). 3D RT adaptive path sensing Method: RSSI modelling validation at 4.5 GHz, 28 GHz, and 38 GHz. Alexandria Engineering Journal, 61(12), 11041-11061. Link

ABSTRACT:

This paper explains a new Adaptive Path Sensing Method (APSM) for indoor radio wave propagation prediction. Measurement campaigns, which cover indoor line-of-sight (LoS), non-line-of-sight (NLoS) and different room scenarios, are conducted at the new Wireless Communication Centre (WCC) block P15a) of Universiti Teknologi Malaysia (UTM), Johor, Malaysia. The proposed APSM is evaluated through a computerized modelling tool by comparing the Received Signal Strength Indicator (RSSI) with measurement data and the conventional Shooting-Bouncing Ray Tracing (SBRT) method. Simulations of the APSM and SBRT are performed with the same layout of the new WCC block P15a by using the exact building dimensions. The results demonstrate that the proposed method achieves a better agreement with measured data, compared to the conventional SBRT outputs. The reduced computational time and resources required are also important milestones to ray tracing technology. The proposed APSM method can assist engineers and researchers to reduce the time required in modelling and optimizing reliable radio propagation in an indoor environment.

SOURCE: Alexandria Engineering Journal

AUTHOR: LIM LI LI (Co-Author) 

RESEARCH CENTRE: CMSP

SDG: 9, 7

CITATION: Faiq, M., Tan, K. G., Liew, C. P., Hossain, F., Tso, C. P., Lim, L. L., ... & Shah, Z. M. (2023). Prediction of energy consumption in campus buildings using long short-term memory. Alexandria Engineering Journal, 67, 65-76. Link

ABSTRACT:

In this paper, Long Short-Term Memory (LSTM) was proposed to predict the energy consumption of an institutional building. A novel energy usage prediction method was demonstrated for daily day-ahead energy consumption by using forecasted weather data. It used weather forecasting data from a local meteorological organization, the Malaysian Meteorological Department (MET). The predictive model was trained by considering the dependencies between energy usage and weather data. The performance of the model was compared with Support Vector Regression (SVR) and Gaussian Process Regression (GPR). The experimental results with a dataset obtained from a building in Multimedia University, Malacca Campus from January 2018 to July 2021 outperformed the SVR and GPR. The proposed model achieved the best RMSE scores (561.692–592.319) when compared to SVR (3135.590–3472.765) and GPR (1243.307–1334.919). Through experimentation and research, the dropout method reduced overfitting significantly. Furthermore, feature analysis was done with SHapley Additive exPlanation to identify the most important weather variables. The results showed that temperature, wind speed, rainfall duration and the amount had a positive effect on the model. Thus, the proposed approach could aid in the implementation of energy policies because accurate predictions of energy consumption could serve as system fault detection and diagnosis for buildings.

SOURCE: Journal of Engineering Science and Technology

AUTHOR: SARA LEE KIT YEE (Co-Author) 

RESEARCH CENTRE: FOET

SDG: 3

CITATION: SIVARAO, S., SIVAKUMAR, S., RAMESH, S., LEE, K. S., SALLEH, M., ALI, M., ... & VATESH, U. (2022). FINITE ELEMENT ANALYSIS OF STRESS DISTRIBUTION ON HIGH-HEELED SHOES. Journal of Engineering Science and Technology, 17(6), 4082-4091. Link

ABSTRACT:

The use of high-heeled shoes has become an increasingly popular among women. However, this type of footwear has contributed a lot to several foot related problems such as muscle pain, spasms, and lower back pain. During static standing position, excess pressure is seen to be located at heel and forefoot region. Finite Element Analysis (FEA) can offer an alternative means to solve biomechanics problems. Preliminary investigations have been done to find out relevant information regarding the design of high-heeled shoe and computational model approach to simulate static standing condition. Static simulation is carried out to study the correlation between heel heights, shoe material, and stress distribution. Peak stress was seen located at the heel region and is in good agreement to previous findings. The current study offers a prior computational approach, which is capable to predict and estimate comprehensive data and results which aims to aid researchers in determining best parameters for design of high-heeled shoes.

SOURCE: Ceramics International

AUTHOR: SARA LEE KIT YEE (Co-Author) 

RESEARCH CENTRE: FOET

SDG: 3, 12

CITATION: Abbas, M. K. G., Ramesh, S., Lee, K. S., Wong, Y. H., Tan, C. Y., Alengaram, U. J., ... & Zalnezhad, E. (2022). Densification of copper oxide doped alumina toughened zirconia by conventional sintering. Ceramics International, 48(5), 6287-6293. Link

ABSTRACT:

The effect of copper oxide doping (0.05–1 wt%) on the densification, microstructure evolution and mechanical characteristics of alumina toughened zirconia (ATZ: 80 wt% Y-TZP + 20 wt% Al2O3) ceramic composites was investigated. Green samples were pressureless sintered using a short hold time of 12 min at temperatures varying from 1250 °C to 1500 °C. The incorporation of up to 0.2 wt% copper oxide was beneficial in promoting densification at low sintering temperature and improving the mechanical properties of ATZ without affecting the tetragonal phase stability. It was found that 0.2 wt% copper oxide addition was most efficacious, and the samples could attain a relative density of approximately 92% at 1250 °C, approximately 97% dense at 1350 °C and above 99% dense at 1450–1500 °C. This approach was also accompanied by an improvement in the Vickers hardness (12.7 GPa) and fracture toughness (6.94 MPam1/2) when consolidated at 1450 °C/12 min. In comparison, the undoped composite exhibited relative densities of approximately 80% at 1250 °C, 87% at 1350 °C and approximately 97%–98% at 1450 °C-1500 °C. However, the study also found that higher dopant levels (0.5 wt% and 1 wt%) was not beneficial because the tetragonal zirconia phase was disrupted upon cooling from sintering, resulting in the monoclinic phase formation. In addition, low densification and poor mechanical properties were obtained.

SOURCE: Sensors

AUTHOR: GOH KAM MENG (Co-Author) 

RESEARCH CENTRE: CMSP

SDG: 9

CITATION: Cheng, X., Chaw, J. K., Goh, K. M., Ting, T. T., Sahrani, S., Ahmad, M. N., ... & Ang, M. C. (2022). Systematic literature review on visual analytics of predictive maintenance in the manufacturing industry. Sensors, 22(17), 6321. Link

ABSTRACT:

The widespread adoption of cyber-physical systems and other cutting-edge digital technology in manufacturing industry production facilities may motivate stakeholders to embrace the idea of Industry 4.0. Some industrial companies already have different sensors installed on their machines; however, without proper analysis, the data collected is not useful. This systematic review’s main goal is to synthesize the existing evidence on the application of predictive maintenance (PdM) with visual aids and to identify the key knowledge gaps in areas including utilities, power generation, industry, and energy consumption. After a thorough search and evaluation for relevancy, 37 documents were identified. Moreover, we identified the visual analytics of PdM, including anomaly detection, planning/scheduling, exploratory data analysis (EDA), and explainable artificial intelligence (XAI). The findings revealed that anomaly detection was a major domain in PdM-related works. We conclude that most of the literature lacks depth in terms of an overall framework that combines data-driven and knowledge-driven techniques of PdM in the manufacturing industry. Some works that utilized both techniques indicated promising results, but there is insufficient research on involving maintenance personnel’s feedback in the latter stage of PdM architecture. Thus, there are still pertinent issues that need to be investigated, and limitations that need to be overcome before PdM is deployed with minimal human involvement.

SOURCE: Scientific Reports

AUTHOR: HOI SU MIN (Main Author) 

RESEARCH CENTRE: FOET

SDG: 9

CITATION: Hoi, S. M., Ooi, E. H., Chew, I. M. L., & Foo, J. J. (2022). SPTV sheds light on flow dynamics of fractal-induced turbulence over a plate-fin array forced convection. Scientific Reports, 12(1), 76. Link

ABSTRACT:

A 3D stationary particle tracking velocimetry (SPTV) with a unique recursive corrective algorithm has been successfully established to detect the instantaneous regional fluid flow characteristics. The veracity of SPTV is corroborated by conducting actual displacement measurement validation, which gives a maximum percentage deviation of about 0.8%. This supports the accuracy of the current SPTV system in 3D position detection. More importantly, the SPTV detected velocity fluctuations are highly repeatable. In this study, SPTV is proven to be able to express the nature of chaotic fractal grid-induced regional turbulence, namely: the high turbulence intensity attributed to multilength-scale wake interactions, the Kolmogorov’s −5/3 law decay, vortex shedding, and the Gaussian flow undulations immediately leeward of the grid followed by non-Gaussian behaviour further downstream. Moreover, by comparing the flow fields between control no-grid and fractal grid-generated turbulence of a plate-fin array, SPTV reveals vigorous turbulence intensity, smaller regional integral-length-scale, and energetic vortex shedding at higher frequency for the latter, particularly between fins. Thereupon, it allows the unravelling of detailed thermofluid interplays of plate-fin heat sink heat transfer augmentation. The novelty of SPTV lies in its simplicity, use of low-cost off-the-shelf components, and most remarkably, low computational complexity in detecting fundamental characteristics of turbulent fluid flow.

SOURCE: Scientific Reports

AUTHOR: HOI SU MIN (Co-Author) 

RESEARCH CENTRE: FOET

SDG: 9

CITATION: Chew, S. H., Hoi, S. M., Tran, M. V., & Foo, J. J. (2022). Partially-covered fractal induced turbulence on fins thermal dissipation. Scientific Reports, 12(1), 7861. Link

ABSTRACT:

The impacts of partially-covered fractal grids induced turbulence on the forced convective heat transfer across plate-fin heat sink at Reynolds number ReDh = 22.0 × 103 were numerically and experimentally investigated. Results showed that partially covered grids rendered a higher thermal dissipation performance, with partially-covered square fractal grid (PCSFG) registering an outstanding increase of 43% in Nusselt number relative to the no grid configuration. The analyzation via an in-house developed single particle tracking velocimetry (SPTV) system displayed the findings of unique “Turbulence Annulus” formation, which provided a small degree of predictivity in the periodic annulus oscillations. Further assessments on PCSFG revealed the preferred inter-fin flow dynamics of (i) high flow velocity, (ii) strong turbulence intensity, (iii) vigorous flow fluctuations, (iv) small turbulence length scale, and (v) heightened decelerated flow events. These features stemmed from the coupling effects of multilength-scale fractal bar thicknesses in generating a veracity of eddy sizes, and a vertical segmentation producing heightened mass flow rate while inducing favourable wake-flow structures to penetrate inter-fin regions. Teeming effects of such energetic eddies within plate-fin array unveiled a powerful vortex shedding effect, with PCSFG achieving fluctuation frequency f = 18.5 Hz close to an optimal magnitude. The coaction of such traits limits the growth of fin boundary layers, providing superior thermal transfer capabilities which benefits the community in developing for higher efficiency heat transfer systems.