UniMAP RIS :: Browsing Publications 2024 by Issue Date

Publication

An update on pathogenesis and clinical scenario for Parkinson’s disease: diagnosis and treatment

( 2023)

Adam Hussaini

;

Subash Chandra Bose Gopinath

;

Nor Azizah Parmin

;

Tijjani Adam

;

Mohd Khairuddin Md Arshad

;

Husein Irzaman

;

Uda Hashim

In severe cases, Parkinson’s disease causes uncontrolled movements known as motor symptoms such as dystonia, rigidity, bradykinesia, and tremors. Parkinson’s disease also causes non-motor symptoms such as insomnia, constipation, depression and hysteria. Disruption of dopaminergic and non-dopaminergic neural networks in the substantia nigra pars compacta is a major cause of motor symptoms in Parkinson’s disease. Furthermore, due to the difficulty of clinical diagnosis of Parkinson’s disease, it is often misdiagnosed, highlighting the need for better methods of detection. Treatment of Parkinson’s disease is also complicated due to the difficulties of medications passing across the blood–brain barrier. Moreover, the conventional methods fail to solve the aforementioned issues. As a result, new methods are needed to detect and treat Parkinson's disease. Improved diagnosis and treatment of Parkinson's disease can help avoid some of its devastating symptoms. This review explores how nanotechnology platforms, such as nanobiosensors and nanomedicine, have improved Parkinson’s disease detection and treatment. Nanobiosensors integrate science and engineering principles to detect Parkinson’s disease. The main advantages are their low cost, portability, and quick and precise analysis. Moreover, nanotechnology can transport medications in the form of nanoparticles across the blood–brain barrier. However, because nanobiosensors are a novel technology, their use in biological systems is limited. Nanobiosensors have the potential to disrupt cell metabolism and homeostasis, changing cellular molecular profiles and making it difficult to distinguish sensor-induced artifacts from fundamental biological phenomena. In the treatment of Parkinson’s disease, nanoparticles, on the other hand, produce neurotoxicity, which is a challenge in the treatment of Parkinson’s disease. Techniques must be developed to distinguish sensor-induced artifacts from fundamental biological phenomena and to reduce the neurotoxicity caused by nanoparticles.

7 17

Publication

Design and Simulation of a Customize Three-axis Gimbal Structure using Finite Element Analysis Method

( 2023-03-01)

Kamaruzzaman M.A.

;

Hassrizal Hassan Basri

;

Mohd Nasir Ayob

This paper presents a Finite Element Analysis (FEA) on a customized three-axis gimbal design application. Examples of applications of the gimbals such as drones, camera stabilizers, and spacecraft. The SolidWorks software checked the gimbal’s FEA characteristics with no existing load or normal conditions. Using the FEA method, a static simulation analysis where the material of this assembly design uses Polylactic Acid (PLA), used mainly by 3D printer machines. The force is given to the gimbal structure and obtains the results of the maximum value of stress in MPa, displacement in mm, and strain. Thus, based on the results obtained from SolidWorks, the structure will not fail. The maximum stress value between parts is 2.31 MPa for the support part and 3.09 MPa for the assembly model when the yield stress value of the PLA material properties is at 70 MPa. The new design structure for the gimbal hardware focuses on academic purposes based on PLA material and is easy to build using a 3D printer. In the summary, the customized three-axis gimbal design using SolidWorks will not fracture when the design is in normal condition which has a total force of 6.87 N, which is equal to 0.70 kg at 3.09 MPa where the weight of the base, O-ring, and servo motors at the U-shape part. In addition, the design can hold up to 230.87 N, which is equal to 23.54 kg at 69.90 MPa of the stress value before it will fail at 70 MPa.

6 49

Publication

SOSFloodFinder: A text-based priority classification system for enhanced decision-making in optimizing emergency flood response

( 2024-01-01)

Kamal S.H.

;

Aziz A.A.

;

Wan Azani Wan Mustafa

Flooding is a significant concern in nations with frequent precipitation because it can instantly affect multiple regions simultaneously. Due to the unpredictability of their occurrence caused by rapid water level rise, it is challenging to predict such natural disasters accurately. During flooding, prompt rescue efforts are crucial for the affected population. Due to flooded highways and residences, rescue teams may have difficulty locating victims. This hinders the potentially perilous and time-consuming rescue operation. To address this problem, we propose a web-based system that integrates natural language processing (NLP) with global positioning system (GPS) functionality. The SOSFloodFinder system provides automatic classification priorities for text messages sent by flood victims, as well as their most recent or current locations. The classification of text based on priority enables efficient resource allocation during rescue operations. In conclusion, this system has the potential to reduce future flood-related fatalities. Additional research and development are necessary to thoroughly investigate this method’s practical capabilities and effectiveness.

Publication

Enhancing Active Power Dispatchability of WTG-BESS Through Integrated Control Considering Wind Forecast Error

( 2024-01-01)

Suboh S.M.

;

Sharma R.

;

Tushar W.

;

Ahamad N.B.

This paper proposes a new integrated control scheme for large-scale wind turbine generators (WTG) incorporated with a battery energy storage system (BESS). The primary goal is to improve the dispatchability of wind power over a wide range. The proposed controller consists of switching feedback controllers for WTG equipped with BESS management and is developed to systematically govern both systems for optimal regulation while ensuring safe operation within defined limits. A scenario-based switching logic is recommended to coordinate the hybrid systems, and a three-layer WTG controller is devised using a gain-scheduled control method. The suggested controller's performance is evaluated through simulation case studies, particularly in dealing with wind forecast errors (WFE) in the short-term dispatch scheme. To assess the proposed controller's effectiveness, a comparison is made against a baseline controller in three criteria: standard deviation (STD), mean ( $\bar {X}$ ) and an integral absolute error (IAE). These criteria help to evaluate the energy mismatch concerning the reference power command. The results are presented to elucidate the effectiveness of the proposed controller in regulating WTG-BESS throughout the entire operating region using a real wind profile from a wind farm in Australia. The findings show that the proposed approach has significant potential to enhance performance, leading to vastly improved wind power dispatch compared to the baseline approach.

Publication

R-Peaks and Wavelet-Based Feature Extraction on K-Nearest Neighbor for ECG Arrhythmia Classification

( 2024-01-01)

Khairuddin A.M.

;

Ku Nurul Fazira Ku Azir

;

Mohd Rashidi Che Beson

The aim of this research is to classify 17 types of arrhythmias by applying the algorithm developed from combining the morphological and the wavelet-based statistical features. The proposed arrhythmia classification algorithm consists of four stages: pre-processing, detection of R-peaks, feature extraction, and classification. Seven morphological features (MF) that were retrieved from the R-peak locations. Following this, another nine wavelet-based statistical features (SF) were gathered by decomposing wavelets in level 4 from the Daubechies 1 wavelet (Db1). These 16 features are then applied to the k-nearest neighbor (k-NN) algorithm. The accuracy (ACC) of the suggested classification algorithm was assessed by using the MIT-BIH arrhythmia benchmark database (MIT-BIHADB). The experimental results of this work attained an average accuracy (ACC) of 99.00%.

Publication

Surface Functionalization of Magnetite Nanoparticles for Remediation Enhancement of Phenol from Aqueous Solutions

( 2024-01-01)

Solan T.D.E.

;

Rozi S.K.M.

;

Saleh N.M.

;

Mohamad S.

;

Ishak A.R.

;

Rahim N.Y.

;

Solan M.D.E.

Phenol is a toxic pollutant generated by industries. It can diminish the supply of clean water and is hazardous to human health. Hence, an effective abatement method is important to remove phenol from water sources. The following amine-functionalized magnetite nanoparticles, ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and polyethylenehexamine (PEHA), were used to study the adsorption performances of phenol from the prepared samples. The morphological study revealed long rod shapes with rough and sharp edges, while the elemental analysis presented the addition of two elements, C and N atoms. In addition, the TETA@MNP possessed weaker magnetism compared to MNPs, showing that the surface functionalization of MNPs was successful. TETA@MNP showed the highest percentage for phenol removal compared to others. The TETA@MNP achieved a removal efficiency of 99.2% at optimum conditions of 60 mg dosage, contact time of 25 min, and pH of 7. TETA@MNP obeyed the pseudo-second-order kinetic model and the Freundlich isotherm model, with coefficients of determination (R2) of 0.9765 and 0.9682, respectively. The reusability study has demonstrated that TETA@MNP can be reused approximately 6 times with extremely minor loss. Therefore, TETA@MNP is a good adsorbent for the adsorption of phenol from prepared sample solutions.

Publication

Experimenting with Variable Arm Quadrotors: Realizing Dynamic Configurations for Enhanced Flight Performance

( 2024-01-01)

Hazry Desa

;

Azizi M.

This paper introduces two innovative concepts for variable arms designed for a quadrotor, enabling precise control of its movement through manipulation of the bending moment via varying arm lengths. The primary objective of this research is to develop and identify the most suitable variable arm configuration that facilitates smooth and stable quadrotor movement. The study delves into two concept designs that are well-suited for the quadrotor application. By employing a suitable variable arm, the quadrotor’s maneuverability can be effectively regulated based on the bending moment adjustments made possible by the variable arm. Ultimately, the paper presents the design and performance testing of two types of variable arms. The obtained results confirm that the variable arm of the electric actuator with linear guide-Type 2 exhibits smooth and stable movement.

Publication

Uncovering Anaerobic Hydrocarbon Biodegradation Pathways in Oil Sands Tailings from Two Different Tailings Ponds via Metabolite and Functional Gene Analyses

( 2024-01-01)

Mohd Faidz Mohamad Shahimin

;

Tariq Siddique

Oil sands tailings, a slurry of alkaline water, silt, clay, unrecovered bitumen, and residual hydrocarbons generated during bitumen extraction, are contained in ponds. Indigenous microbes metabolize hydrocarbons and emit greenhouse gases from the tailings. Metabolism of hydrocarbons in tailings ponds of two operators, namely, Canadian Natural Upgrading Limited (CNUL) and Canadian Natural Resources Limited (CNRL), has not been comprehensively investigated. Previous reports have revealed sequential and preferential hydrocarbon degradation of alkanes in primary cultures established from CNUL and CNRL tailings amended separately with mixtures of hydrocarbons (n-alkanes, iso-alkanes, paraffinic solvent, or naphtha). In this study, activation pathway of hydrocarbon biodegradation in these primary cultures was investigated. The functional gene analysis revealed that fumarate addition was potentially the primary activation pathway of alkanes in all cultures. However, the metabolite analysis only detected transient succinylated 2-methylpentane and 2-methylbutane metabolites during initial methanogenic biodegradation of iso-alkanes and paraffinic solvent in all CNUL and CNRL cultures amended with iso-alkanes and paraffinic solvent. Under sulfidogenic conditions (prepared only with CNUL tailings amended with iso-alkanes), succinylated 2-methylpentane persisted throughout incubation period of ~ 1100 days, implying dead-end nature of the metabolite. Though no metabolite was detected in n-alkanes- and naphtha-amended cultures during incubation, assA/masD genes related to Peptococcaceae were amplified in all CNUL and CNRL primary cultures. The findings of this present study suggest that microbial communities in different tailings ponds can biodegrade hydrocarbons through fumarate addition as activation pathway under methanogenic and sulfidogenic conditions.

Publication

Delaying the Ripening of Banana Fruit and Increased Storage Shelf-Life Using Hydrophobic Deep Eutectic Oil (Menthol–Thymol)-In-Water Nanoemulsion Coating

( 2024-01-01)

Gidado M.J.

;

Ahmad Anas Nagoor Gunny

;

Sri Alamelu Sankari R.

;

Subash Chandra Bose Gopinath

;

Wongs-Aree C.

;

Shukor H.

;

Ibrahim R.

Hydrophobic deep eutectic oil (menthol-thymol)-in-water nanoemulsion was developed to preserve the quality of banana fruit and extend their storage shelf life. Storage preservation of bananas presents several challenges due to their high respiration rate, ethylene production, and susceptibility to various physiological and biochemical changes. The storage shelf life of bananas is relatively short compared to other fruits due to the combination of rapid ripening and sensitivity to ethylene and temperature. In this study, the effectiveness of HyDEN treatment was assessed on changes in banana fruit’s physiological parameters such as firmness, weight loss, total soluble solids, titratable acidity, and colour for 14 days storage time [25 °C ± 1 °C, 67% relative humidity (RH)]. HyDEN treatment preserved the physicochemical characteristics of banana fruit and was effective in delaying the ripening process. The storage shelf life of banana fruit treated with HyDEN increased for 14 days compared to control that ripened and physically damaged after 8 days of storage. This study provided a new delivery system for applying HyDEN as an edible coating to fruit after harvest preservation.

Publication

The behaviour of Reinforced Concrete Beams by Using Expanded Polystyrene Beads and Palm Oil Fuel Ash as Replacement Materials

( 2024-01-01)

Osman M.H.

;

Chin L.Y.

;

Suraya Hani Adnan

;

Jeni M.L.M.

;

Jusoh W.A.W.

;

Salim S.

;

Nur Liza Rahim

;

Wysłocki J.J.

The Reinforced Concrete (RC) beams containing Expanded Polystyrene Beads (EPS) and Palm Oil Fuel Ash (POFA) as sand and cement replacement with a percentage between 10% and 30%were studied in terms of load-deflection behaviour. RC beam’s size was 1000×150×150 mm and simply supported at spaced 750 mm apart. The 10% of POFA without EPS shows a slight increase which is 0.26% higher than normal concrete in compressive strength. The ultimate load and flexural performance of RC beams with EPS and POFA exhibited a decreasing trend. All beams’ ultimate load exceeds the design value. The cracks of the RC beam may be classified as vertical flexural cracks, and some of the cracks can be classified as shear cracks based on the crack angle. As the percentage of EPS and POFA increases above 20% for all specimens, cracking starts to change to shear cracking.

Publication

Oil palm waste-derived reduced graphene oxide (rGO) for dynamic adsorption of dye in a fixed-bed system

( 2024-01-01)

Mohd Ali Jinnah S.N.H.

;

Umi Fazara Md Ali

;

Subash Chandra Bose Gopinath

;

Naimah Ibrahim

;

Razi Ahmad

;

Mohamed Zuki F.

This study focuses on investigating the dynamic adsorption of Rhodamine B (RhB) from reduced graphene oxide (rGO) derived from oil palm waste. The synthesis of rGO from palm kernel shell (PKS) was achieved through double oxidation and carbonization method, resulting in a yield of 73.5 wt%. The reduction of oxygen-containing functionalities process using PKS was confirmed by FTIR spectroscopy, microscopic evaluation, and X-ray diffraction analyses. Laboratory-scale fixed-bed experiments were conducted with various process parameters. Both PKS and rGO were used as adsorbents, and a comparison was made based on breakthrough curve analysis, adsorption capacity and percentage removal of dye. The adsorption kinetics of RhB on PKS and rGO were best described by the non-linear Yoon-Nelson model, with a high adsorption capacity of 88.32 mg/g and 195.24 mg/g respectively. Using both PKS and rGO, the maximum adsorption capacity was observed when using 10 cm bed depth column, inlet dye concentration of 5 mg/L, flow rate of 12 mL/min and pH of 7. PKS exhibited good dye removal with an efficiency of 66.54%. Meanwhile, the exothermic behavior highlighted the potential of utilizing rGO for maximum dye removal, achieving an efficiency of 90.35%. This study justifies rGO as a cost-effective superior dye removal adsorbent, providing new prospect for large-scale dye removal.

Publication

Self-Isolated Frequency Reconfigurable two-port MIMO Antenna for 5G Application

( 2024-01-01)

Angadi S.

;

Sharma Y.

;

Rghava S.N.

;

Thennarasan Sabapathy

In this work two-port multiple input multiple output (MIMO) antenna with self-isolation between antenna elements is presented. Initially, the proposed antenna is constructed as a single-port square-shaped radiating patch connected diagonally with a stub to operate the antenna in frequency reconfigurable mode. A 2×2 mm slot is cut at the middle part of the stub for implementing reconfigurability on the radiating patch to operate the antenna in multi-functional mode. Later the proposed antenna is converted to two-port frequency reconfigurable MIMO antenna that realizes an S11 below -10 dB intended for two resonant bands operating at 3.79 GHz (3.41-4.04 GHz) with pin-diode off-mode and 4.53 GHz (4.69-4.88 GHz) in on-mode with maximum peak realized gain of 4.93 dB at diode off-mode and 4.55 dB in pin diode on-mode. moreover, the gain is enhanced by 1.5 dB after converting to the two-port antenna. The two feeding ports of the proposed antenna are positioned orthogonal to each other to permit the antenna in self-isolation mode without connecting any de-coupling circuit and maintaining the mutual coupling (S21) below-21 dB in off-mode and -29.50 dB in diode on-mode. The distance between antenna elements is 0.12 λ0. In addition to that, two-port MIMO of envelope correlation coefficient (ECC), channel capacity loss (CCL), total active reflection coefficient (TARC), mean effective gain (MEG), and diversity gain (DG) are simulated. The designed antenna is applicable for 5G new radio (NR) bands of n48, n78 in off-mode, and n79 in on-mode respectively.

Publication

The Effect of Cross Sectional Properties of Concrete Column on the Repair Material: A Review

( 2024-01-01)

Ali S.A.A.

;

Zahid M.Z.A.M.

;

Razak S.M.

;

Rahim N.L.

;

Johari I.

The utilization of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) as a material for repairing concrete structures holds immense promise and potential. UHPFRC usage in concrete has been a significant rise in the interest surrounding the enhancement and renovation of concrete structures, particularly focusing on columns. UHPFRC has showcased remarkable bonding potency with concrete, along with an impressive capacity to renew the load-bearing capability of compromised reinforced concrete columns. However, the limited application of UHPRFC as a repair material for concrete columns is primarily attributable to a lack of comprehension regarding the influence of shape and size effects, particularly as they pertain to square and rectangular columns. In this paper, the factors behind the impact of cross-sectional properties on the effectiveness of UHPFRC as a repair material is presented. Therefore, it can be adopted by researchers to explore the UHPFRC potential in structural rehabilitation applications especially for concrete columns. It is believed that the relationship between the cross-sectional area, aspect ratio, and corner radius ratio of the column and repair material is a vital parameter affecting the performance of repaired columns.

Publication

Revisiting job characteristics and job satisfaction: A systematic review with bibliographic analysis

( 2024-01-01)

Mostafa R.

;

Jaafar H.J.B.

This systematic review with bibliographic analysis revisits the association between job characteristics and job satisfaction, aiming to identify thematic clusters that underlie this association. With the objective of discerning the multifaceted dynamics within the realm of organizational psychology, this study focuses on elucidating key themes that contribute to employees' overall satisfaction in the workplace. The primary thematic clusters identified in this study include learning and growth opportunities, health, and well-being. Using the Scopus database, a comprehensive collection of relevant literature was obtained, resulting in a total of 729 documents. Following the PRISMA approach, a meticulous screening process was conducted to select papers for inclusion in the analysis. A total of 15 papers were selected for reporting, encompassing a diverse range of studies that explored various facets of job characteristics and their impact on job satisfaction. The results of this comprehensive analysis underscore the significant influence of job attributes on employees' interpretations of their workplace atmosphere and their overall satisfaction with their employment. Learning and growth opportunities emerge as significant determinants of job satisfaction, emphasizing the importance of continuous development and skill enhancement within the workplace. Additionally, the themes of health and well-being underscore the significance of creating a supportive and conducive work environment that prioritizes employee well-being and fosters a healthy work-life balance. By synthesizing the literature and identifying key thematic clusters, this study contributes to a deeper understanding of the complex interplay between job characteristics and job satisfaction. Ultimately, by addressing the identified thematic clusters, organizations can strive to create work environments that stimulate employee engagement, satisfaction, and overall well-being.

Publication

Integration of Hybrid Networks, AI, Ultra Massive-MIMO, THz Frequency, and FBMC Modulation Toward 6G Requirements: A Review

( 2024-01-01)

Alhaj N.A.

;

Jamlos M.F.

;

Manap S.A.

;

Abdelsalam S.

;

Bakhit A.A.

;

Mamat R.

;

Mohd Aminudin Jamlos

;

Gismalla M.S.M.

;

Hamdan M.

The fifth-generation (5G) wireless communications have been deployed in many countries with the following features: wireless networks at 20 Gbps as peak data rate, a latency of 1-ms, reliability of 99.999%, maximum mobility of 500 km/h, a bandwidth of 1-GHz, and a capacity of 106 up to Mbps/m2. Nonetheless, the rapid growth of applications, such as extended/virtual reality (XR/VR), online gaming, telemedicine, cloud computing, smart cities, the Internet of Everything (IoE), and others, demand lower latency, higher data rates, ubiquitous coverage, and better reliability. These higher requirements are the main problems that have challenged 5G while concurrently encouraging researchers and practitioners to introduce viable solutions. In this review paper, the sixth-generation (6G) technology could solve the 5G limitations, achieve higher requirements, and support future applications. The integration of multiple access techniques, terahertz (THz), visible light communications (VLC), ultra-massive multiple-input multiple-output ( μm -MIMO), hybrid networks, cell-free massive MIMO, and artificial intelligence (AI)/machine learning (ML) have been proposed for 6G. The main contributions of this paper are a comprehensive review of the 6G vision, KPIs (key performance indicators), and advanced potential technologies proposed with operation principles. Besides, this paper reviewed multiple access and modulation techniques, concentrating on Filter-Bank Multicarrier (FBMC) as a potential technology for 6G. This paper ends by discussing potential applications with challenges and lessons identified from prior studies to pave the path for future research.

Publication

COVID-19 Detection System with Gradient Vector Flow Snake

( 2024-01-01)

Jusman Y.

;

Almizar N.

;

Widyasmoro

;

Tyassari W.

;

Kanafiah S.N.A.M.

COVID-19, attacking the lung and respiratory system, can infect people of all ages since it is easily transmitted through contact with sufferers. However, despite having similar symptoms to pneumonia, COVID-19 is more dangerous as late diagnosis can lead to death. COVID-19 and pneumonia diagnosis can be performed using chest X-ray images. This study aims to detect COVID-19 in chest X-ray images using Gradient Vector Flow Snake (GVFS) segmentation and Hu Moment extraction, with Support Vector Machine (SVM) and K-Nearest Neighbor (KNN) as the classification methods. Chest X-ray image data were obtained from Joseph Paul Cohen's Github open source from various hospitals in various parts of the country by taking three image classes: COVID-19, normal, and pneumonia. Hu Moment Cubic KNN outperformed other methods by producing the greatest training accuracy of 56.20% and the highest testing accuracy of 66.30%.

Publication

CHARACTERISATION OF POMACEA CANALICULATA EGGS TREATED WITH PROTEASE

( 2024-01-01)

Noor Hasyierah Mohd Salleh

;

Nurhadijah Zainalabidin

;

Siti Noor Hajjar Md Latip

Pomacea canaliculata is a type of freshwater snail that has become a major pest in paddy fields, as it feeds on young paddy leaves and stems, thus, posing a serious threat to paddy production. It was named one of the world’s top 100 worst invasive species, with serious consequences for the environment, human health, and the social economy. Their hatchability rate is high, which explains their global distribution worldwide. Therefore, it is vital to manage their hatchability to prevent their population from expanding further by understanding the protection that permits the eggs to survive. P. canaliculata eggs are covered with a thin layer of cuticle that is rich in protein to protect the embryo during the hatching process. The biological treatment with protease enzyme successfully hydrolysed the protein cuticle layer, lowering the percentage of hatchability. Disruption of the protein cuticle may have an impact on conductivity, water loss, hatching time, protein content, and other factors. However, documentation of the protease effect on the protein cuticle is scarce. Therefore, the goal of this study is to evaluate the protease treatment on the protein cuticle of P. canaliculata eggs physically (conductivity, water loss, and morphological analysis) and chemically (cuticle protein content, protein breakdown, and amino acid profile). Physical characterisation revealed that protease-treated eggs have higher conductivity and water loss than the control egg. Images taken with a light microscope (LM) and a scanning electron microscope (SEM) revealed changes in cuticle structure, which explained the protease-induced cuticle hydrolysis. Chemical characterisation revealed a decrease in cuticle protein content, hydrolysis of protein to a small size, and changes in amino acid composition. The physical and chemical analyses strongly suggested that protease can damage the cuticle protein, thus, preventing the eggs from hatching.

Publication

A Preliminary Investigation on The Correlation Between the Arrival Time of Ultrasonic Signals and The Concrete Condition

( 2024-01-01)

Mohamad F.A.J.

;

AA. Ahmad

;

Rahim R.A.

;

Ibrahim S.

;

Jamaludin J.

;

Ahmad N.

;

Yunus F.R.M.

;

Mohd Hafiz Fazalul Rahiman

;

Zaini N.A.H.S.

Concrete is a composite material that is widely used in a construction project. The evaluation of concrete structure is very important in order to determine its strength and quality. Concrete is commonly evaluated by using the ultrasonic pulse velocity (UPV) method, which adopted the concept of measuring time of a first arrival of the received signal. Hence, this paper aims to evaluate the first arrival time of the detected ultrasonic signals based on different conditions of concrete structure. A simulation study was conducted by using COMSOL Multiphysics software version 5.6. Data collected were categorized into three sections, including in concrete model with inclusion of air hole, crack, and rust. From the simulation results, concrete models with inclusion of air hole showed an increment in the arrival time as the size of air hole increase. For the concrete models with rust, the arrival time were significantly increased in 20-mm and 40-mm rust, however it turns down as the size of rust reached 60-mm. The results also indicated that transverse crack took a longer arrival time compared to other orientation of crack.

Publication

Sound absorption coefficient measurement and analysis for multisection perforation microperforated panel

( 2024-01-01)

Tan W.H.

;

Wahab F.

;

Mat F.

;

Chan C.K.

;

Teoh R.J.

The microperforated panel (MPP) is a resonant-type sound-absorbing material considered the next-generation sound-absorption material due to its attractive characteristics. However, the drawback of narrow bandwidth sound absorption remains a matter of concern. This study explored the impact of varying backing cavity depths and different combinations of multi-section perforation sizes on the sound absorption performance of microperforated panels (MPP). A two-microphone impedance tube was used to obtain the sound absorption coefficient (SAC) of MPP following the ISO 10534-2 standard. MPP with single-size perforation diameters of 0.5, 0.7, and 1.0 mm which were compared to multi-section MPP with combinations perforation sizes of 0.5 & 0.7, 0.7 & 1.0, and 0.5 & 1.0 mm. The investigation reveals that increasing the backing cavity depth from 1.0 cm to 3.0 cm generally shifts the sound absorption coefficient (SAC) peak to a lower frequency range and decreases the SAC peak across all MPP samples. A higher SAC peak and wider absorption bandwidth were achieved from 0.5 mm single-size perforation diameter MPP and its combination in multi-section perforation MPP.

Publication

Aerobic Co-composting of Spent Mushroom Medium Using Food Waste Fermented Liquid

( 2024-01-01)

Siti Nazrah Zailani

;

Zaidnuddin A.S.

;

Mokhtar N.F.

;

Zulaika E.

;

Shovitri M.

;

Kuswytasari N.D.

;

Hidayati D.

;

Zabidi K.A.A.

Spent mushroom medium and dried sludge from bioethanol industry can be utilized into beneficial organic compost after completion the composting process. Food waste fermented liquid and commercially effective microorganisms (EM) from EMRO Sdn. Bhd. were used as the microbial inoculant for the aerobic composting. Three kg of composting pile made of spent mushroom and dried sludge are used to obtain a 23.07 C/N ratio at the initial composting process. In order to ascertain the impact of composting process in seven days, the sample from each of the composting beds for analysis of temperature, pH, moisture, and total organic matter was assessed. Food waste fermented liquid and commercial EM composts reached the thermophilic phase (40 °C) after a day of the composting process. Moisture content showed a significant result for both composting piles on day 1 due to the highest evaporation of water at the thermophilic phase. The composting process was not extended until reached stability and maturity phases; thus, the pH for both composting piles was recorded at 9, which is far from the stable compost normally at neutral pH (~7). The organic matter content of each composting pile showed gradually decreased during the composting process. The degradation rate for the composting pile using food waste fermented liquid showed slightly higher than commercial EM which was 0.0363 and 0.0232 day 1, respectively. In conclusion, food waste fermented liquid shall be used as a replacement for EM commercial as a microbial inoculant for the composting process based on the results shown in this study.

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