Journal Articles

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https://hdl.handle.net/20.500.14170/296

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  • Publication
    A BIM-based model checking in the green building maintenance: a review
    (Emerald Publishing, 2023)
    Zul-Atfi Ismail
    Purpose: This paper aims to identify the different system approach using building information modelling (BIM) technology that is equipped with automated evaluation processes. BIM research has mainly focused on theoretical models of acceptance in the green building (GB) maintenance industry. However, BIM has the potential to the competency’s performance and design knowledge of building control instrument. Realising this potential requires a study of BIM at the maintenance planning level, which is considered to be BIM-based model checking (BMC). BMC and its effect in the maintenance planning have not been sufficiently investigated. Design/methodology/approach: The aim of this paper is to present a critical review of literature on the theoretical background of BMC practices and the main features of information and communication technology tools and techniques in the GB maintenance projects. Findings: A theoretical framework of BMC is developed and presented. The proposed model incorporates requirement for maintaining a competency’s performance on maintenance planning schemes of GB projects and the importance of early integration of BMC in the design phase to identify alternative methods to cogenerate, monitor and optimise BMC. Originality/value: It is found that variables facilitating BMC are integrated at different GB maintenance environments levels and are shaped by the context. Directions for future research are presented.
  • Publication
    A critical study of the existing issues in circular economy practices during movement control order: can BIM fill the gap?
    (Emerald, 2022)
    Zul-Atfi Ismail
    The improper evaluation and information management of circular economy (CE) (i.e. design, planning, supply chain, waste pile and material hazard) is critical for public health and is a major problem in the waste management of precast concrete (PC) building manufacture and construction and demolition wastes industry. The CE model is particularly problematic for PC building construction projects where the standard practices for the total number of waste building materials are not appropriate and do not match the safe disposal design specification, such as the recent number increase in the Malaysian illegal construction waste pile during the Movement Control Order (11 March 2021, about 5 out of 29 landfills related to states enforcing Act 672). The study aims to develop a framework application (i.e. Building Information Modelling [BIM]) that supports intelligent waste recycling management and sophisticated CE model system solutions. Design/methodology/approach: Thus, the development of a new BIM-based programming algorithm approach is proposed for optimising CE in accordance with the needs of the current PC building construction schemes. As a precursor to this study, the concepts of CE practices are reviewed and the main features of BIM tools and techniques currently being employed on such projects are presented. Findings: Sophisticated CE system solutions are described as an essential component of this optimisation to reduce the amount of waste generated at the end of the life cycle of PC building construction projects and to better manage the resources used throughout it. Originality/value: Finally, the potential for a research framework for developing such a system in the future is presented.
  • Publication
    A DCV performance in IAQ services during COVID-19: a study of the contractor in Malaysia
    (Emerald Publishing, 2025-02)
    Zul-Atfi Ismail
    Demand-controlled ventilation (DCV) plays a significant role in human life by providing safe, reliable and cost-effective services that are environmentally friendly and enhance occupant satisfaction and building energy efficiency. Significant decisions are made at the early stages of building sector DCV systems, requiring effective tools to avoid measurement errors and failures in Volatile Organic Compound (VOC) generation. The continuous upgrading of this sector is necessary to respond to technological advances, environmental changes and increased ventilation demands. Integrating indoor air quality (IAQ) and machine learning algorithms (MLA) proves promising, as the scope of DCV typically does not extend beyond the footprint of the building; it does not encompass IAQ within a Corona Virus Disease 2019 (COVID-19) infection risk information. Therefore, integrating IAQ with MLA provides a comprehensive overview of the building sector’s DCV systems. However, this integration poses challenges, particularly in DCV activities, as they are among the most complex systems involving numerous processes critical for making important decisions. This study aims to identify how digitalized construction environments can integrate DCV into their processes.
  • Publication
    A hydrosuction siphon system to remove particles using fan blades
    (MDPI, 2023-01)
    Mohammed Hamid Rasool
    ;
    Mohd Remy Rozainy Mohd Arif Zainol
    ;
    Norazian Mohamed Noor
    ;
    Mohd Sharizal Abdul Aziz
    ;
    Mohd Hafiz Zawawi
    ;
    Muhammad Khairi A. Wahab
    ;
    Mohd Azmeer Abu Bakar
    Sedimentation in dam reservoirs can cause problems that lead to loss of storage capacity and decrease in the flood control volume. Hydrosuction sediment removal is one of the methods used to remove sediments from within a reservoir using the suction energy provided by the effective head. In this study, a new tool has been developed by attaching the reservoir to a suction pipe intake point and using a simple fan blade mechanism for the hydrosuction sediment removal system. This mechanism is used to create a vortex flow to suspend the settled particles. This paper investigated the effects of the fan blade angles, effective head, and inlet height from the surface of layer particles on the performance and efficiency of fan blades hydrosuction sediment removal (FBHSSR) and hydrosuction sediment removal (HSSR) systems based on the geometric scour hole parameters. Results from the experimental tests indicated the effectiveness of the FBHSSR system, with the fan blade angles of 30°, 45°, and 60° leading to approximately 800%, 200%, and 117%, respectively, removed particles greater than those of the HSSR system. Furthermore, the maximum depth and diameter of the scour hole were increased by 206%, 200%, and 137% and 135, 112%, and 117%, respectively, for each angle. The effective head or experiment time also enhanced system performance by increasing the suction discharge, but no change was observed in terms of efficiency. The critical inlet heights for the FBHSSR and HSSR systems are 1 time and 2.54 times, respectively, more than the diameter of the suction pipe. Thus, it can be concluded that using fan blades in HSSR systems is a good approach to improve the properties of the scour hole.
  • Publication
    A novel road traffic flow prediction model using hybrid Particle Swarm Optimization (PSO) and Radial Basis Function Neural Network (RBFNN)
    (Frontier Scientific Publishing Pte Ltd., 2023)
    Shanhua Zhang
    ;
    Hong Ki An
    Traffic congestion is a major problem in urban areas, leading to increased travel time, air pollution, and fuel consumption. Road impedance function, which describes the relationship between traffic status and travel time, plays an important role in predicting travel time and managing traffic flow. Traditional methods for estimating road impedance function rely on manual calibration and may have limitations in reflecting the complexity of traffic patterns. To address these challenges, researchers have proposed various machine learning models for predicting travel time and road impedance function. In this paper, a hybrid particle swarm optimization—radial basis function neural network model is proposed for improving the accuracy of the road impedance function. The model takes into consideration various vehicle types and is validated using travel time data collected from a road section in Huai’an City, China. The effectiveness of the proposed model is compared with the traditional road impedance function calibrated by nonlinear regression. The experimental results indicate that the Mean Relative Error (MRE) of PSORBFNN is increased by 3.89% and 6.28% respectively when compared with DPNR training samples and validation samples. When compared with DPPSO training and validation samples, the MRE of PSORBFNN is increased by 2.87% and 3.3% respectively. These findings suggest that the proposed model could guide and assist traffic engineers and practitioners in predicting travel time on road sections with improved accuracy.
  • Publication
    A Properties of Municipal Solid Waste Incineration Fly Ash (IFA) And Cement Used in The Manufacturing of New Inventive Blended Cement
    ( 2022-01-01)
    Norlia Mohamad Ibrahim
    ;
    Roshazita Che Amat
    ;
    Nur Liza Rahim
    ;
    Izzatul Nurain Che Sang Beri
    ;
    Syakirah Afiza Mohammed
    ;
    Zailani W.W.A.
    Municipal solid waste incinerator fly (IFA) ash is prone to accumulate high concentration heavy metals. Due to the increasing costs to treat remaining fly ash at the landfill, a lot of research has been done to recycle IFA. This study was focusing on the properties of IFA and cement as main raw materials in new inventive blended cement. The properties of blended cement were also being investigated. Properties of IFA and cement were examined through several test which includes density, specific gravity, X-Ray Fluorescence (XRF), Loss of Ignition (LOI) and through Toxicity Characteristic Leaching Procedure (TCLP) test. The density test and LOI test were also being done for the blended cement. From the tests for IFA and cement, it can be found that density the density of fly ash and cement that has been used for this study were found to be 0.76 g/cm3 and 3.67 g/cm3 respectively. Then, the specific gravity of fly ash and cement were 1.69 and 2.98, accordingly. XRF results shows that both materials have highest content of aluminium, silica and iron, as expected. LOI of fly ash and cement were found to be 17.33 % and 12.33 %, respectively. In terms of the leaching rates of heavy metals (Mn, Ni, Cd, Cr, Cu), only Cd leached at rate 2.39 mg/L, which is above the USEPA's regulatory level, 1.0 mg/L. 5 %, 10 % and 15 % of IFA was mixed with cement to produced blended cement. As the density of blended cement, it was found to be 1.12 g/cm3, 1.08 g/cm3 and 1.09 g/cm3 for each of 5 %, 10 % and 15 % of fly ash in blended cement.
      5  30
  • Publication
    A proposed aerobic granules size development scheme for aerobic granulation process
    ( 2015-04)
    Farrah Aini Dahalan
    ;
    Norhayati Abdullah
    ;
    Ali Yuzir
    ;
    Gustaf Olsson
    ;
    Myzairah Salmiati
    ;
    Mohd Fadhil Mohd Hamdzah
    ;
    Siti Aqlima Din
    ;
    Khalilah Abdul Ahmad
    ;
    Aznah Nor Khalil
    ;
    Zainura Zainon Anuar
    ;
    Zaini Noor
    Aerobic granulation is increasingly used in wastewater treatment due to its unique physical properties and microbial functionalities. Granule size defines the physical properties of granules based on biomass accumulation. This study aims to determine the profile of size development under two physicochemical conditions. Two identical bioreactors namely Rnp and Rp were operated under non-phototrophic and phototrophic conditions, respectively. An illustrative scheme was developed to comprehend the mechanism of size development that delineates the granular size throughout the granulation. Observations on granules’ size variation have shown that activated sludge revolutionised into the form of aerobic granules through the increase of biomass concentration in bioreactors which also determined the changes of granule size. Both reactors demonstrated that size transformed in a similar trend when tested with and without illumination. Thus, different types of aerobic granules may increase in size in the same way as recommended in the aerobic granule size development scheme.
  • Publication
    A recent study on Industrialized Building System (IBS) in Malaysian construction industry: a systematic review
    (Semarak Ilmu Publishing, 2025-05)
    Nurfadzillah Ishak
    ;
    Noorul Amilin Saipudin
    ;
    Nurul Ain Saipudin
    ;
    Mohd Said Abdul Kadir
    The construction sector has witnessed a significant increase in the use of Industrialized Building Systems (IBS) as a viable remedy for challenges related to productivity, cost effectiveness, and sustainability. Nevertheless, despite the increasing attention and extensive study conducted on this subject, there exists a significant requirement for a thorough and current evaluation of the most recent advancements in the field of Industrialized Building Systems (IBS). The primary aim of this systematic review is to fill in the current gaps in knowledge by undertaking a thorough examination of the current scientific literature and to give a thorough and up-to-date summary of the current research results on Industrialized Building Systems (IBS) in the Malaysian construction sector using a rigorous methodology that includes systematic search, screening, and synthesis. The expected outcomes are the recognition of developing patterns, inventive technology, and original methodologies in the application of IBS, along by a thorough analysis of their consequences and any obstacles. This article seeks to make a substantial contribution to the academic discussion on Industrialized Building Systems (IBS) by integrating the most recent findings. The final primary data was evaluated after a thorough search of the Scopus and Web of Science databases (n = 23). This systematic study aims to provide industry professionals, policymakers, and researchers with an understanding of the current advancements in the field. Furthermore, this study also aims to provide valuable insights for future research endeavours and practical implementations in the dynamic field of building.
      3  2
  • Publication
    A State-of-the-Art review on innovative geopolymer composites designed for water and wastewater treatment
    ( 2021)
    Ismail Luhar
    ;
    Salmabanu Luhar
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Rafiza Abd Razak
    ;
    Petrica Vizureanu
    ;
    Andrei Victor Sandu
    ;
    Petre-Daniel Matasaru
    There is nothing more fundamental than clean potable water for living beings next to air. On the other hand, wastewater management is cropping up as a challenging task day-by-day due to lots of new additions of novel pollutants as well as the development of infrastructures and regulations that could not maintain its pace with the burgeoning escalation of populace and urbanizations. Therefore, momentous approaches must be sought-after to reclaim fresh water from wastewaters in order to address this great societal challenge. One of the routes is to clean wastewater through treatment processes using diverse adsorbents. However, most of them are unsustainable and quite costly e.g. activated carbon adsorbents, etc. Quite recently, innovative, sustainable, durable, affordable, user and eco-benevolent Geopolymer composites have been brought into play to serve the purpose as a pretty novel subject matter since they can be manufactured by a simple process of Geopolymerization at low temperature, lower energy with mitigated carbon footprints and marvellously, exhibit outstanding properties of physical and chemical stability, ion-exchange, dielectric characteristics, etc., with a porous structure and of course lucrative too because of the incorporation of wastes with them, which is in harmony with the goal to transit from linear to circular economy, i.e., “one’s waste is the treasure for another”. For these reasons, nowadays, this ground-breaking inorganic class of amorphous alumina-silicate materials are drawing the attention of the world researchers for designing them as adsorbents for water and wastewater treatment where the chemical nature and structure of the materials have a great impact on their adsorption competence. The aim of the current most recent state-of-the-art and scientometric review is to comprehend and assess thoroughly the advancements in geo-synthesis, properties and applications of geopolymer composites designed for the elimination of hazardous contaminants viz., heavy metal ions, dyes, etc. The adsorption mechanisms and effects of various environmental conditions on adsorption efficiency are also taken into account for review of the importance of Geopolymers as most recent adsorbents to get rid of the death-defying and toxic pollutants from wastewater with a view to obtaining reclaimed potable and sparkling water for reuse offering to trim down the massive crisis of scarcity of water promoting sustainable water and wastewater treatment for greener environments. The appraisal is made on the performance estimation of Geopolymers for water and wastewater treatment along with the three-dimensional printed components are characterized for mechanical, physical and chemical attributes, permeability and Ammonium (NH4+) ion removal competence of Geopolymer composites as alternative adsorbents for sequestration of an assortment of contaminants during wastewater treatment.
      30  1
  • Publication
    A study on the effect of flooding depths and duration on soil subgrade performance and stability
    (GEOMATE International Society, 2020)
    Muhd Shahril Nizam Ismail
    ;
    Ghani, Abdul Naser Abdul
    ;
    Zuhayr Md Ghazaly
    ;
    Close Dafalla, Muawia
    In the event of flooding, the road infrastructure especially the subgrade will be affected in terms of its capacity to support the pavement. It is well known that subgrade deterioration will eventually cause pavement failure. However, little is known on how the subgrade reacts to different flooding conditions especially in terms of the depth and duration of the floods. The aims of this study are to evaluate the moisture content variation and strength of the subgrade using the flood simulation model. The pavement loading characteristics are referred to the Manual on Flexible Pavement Design published by the Malaysian Public Works Department (ATJ 5/85 Rev. 2013). The flood parameters used for this experimental model are based on actual data of flooding events from 1991 to 2014. It includes the parameters of flood water level, flood duration and repeated flooding. The samples were exposed to flooding for a duration of 3, 24 and 48 hours for unrepeated flooding and 2, 5, and 24 hours for repeated flooding. Flood water levels were set to 0.3 m, 0.6 m and 1 m. This study shows that there is a strong relationship between moisture content and subgrade strength. The increase in the duration of the flooding affected the performance of the subgrade due to the increasing moisture content. The study also revealed that the rate of deterioration in subgrade strength for second flooding events is 15% more than for first flooding events. The result of this experiment will be used to develop the basis for including flooding characteristics in the modified California Bearing Ratio test for soils in flood prone areas.
  • Publication
    Adsorption and toxicity of heavy metals on activated sludge
    ( 2010)
    Ong Soon An
    ;
    Eiichi Toorisaka
    ;
    Makoto Hirata
    ;
    Tadashi Hano
    The adsorption of Cu, Cd, Ni, Zn, and Cr from synthetic solutions on powdered activated carbon (PAC), activated sludge, and dried sludge were investigated under laboratory conditions to assess its ability to remove heavy metals. The adsorption efficiency increased rapidly within the first 30 min and then slowed down as it approached a steady state after 5 h of contact time. The results showed that activated sludge and PAC had a higher adsorption capacity than dried sludge. However, PAC showed a better adsorption capacity for Cu, Zn, and Ni than activated sludge. The maximum adsorption capacity, as quantified by the Langmuir parameter Q for activated sludge was 44, 30, 24, 23, and 18 mg/g for Cu, Ni, Cd, Cr, and Zn, respectively. In the case of dried sludge, the respective values of Q were 20, 13, 11, 3, and 10 mg/g. The acute toxicity of these five heavy metals to the activated sludge microorganisms was determined on the basis of the reduction in the specific oxygen uptake rate (SOUR). The results obtained from the SOUR measurements indicated a decreasing toxicity scale, Cu > Cd > Ni ' Cr > Zn on activated sludge microorganisms.
      1  12
  • Publication
    Adsorption of diclofenac sodium using low-cost activated carbon in a fixed-bed column
    ( 2022-12-15)
    Fadirah Fadzail
    ;
    Masitah Hasan
    ;
    Naimah Ibrahim
    ;
    Zulfakar Mokhtar
    ;
    Asih A.Y.P.
    ;
    Syafiuddin A.
    In recent years, the presence of pharmaceutical contaminants, such as diclofenac sodium (DCF) in water bodies and their potential influence on aquatic organisms gained much attention. As a result of high demand and usage by consumers, in addition to incomplete removal during wastewater treatment, pharmaceutical contaminants will end up on water surfaces. To mitigate this problem, the elimination of DCF by employing activated carbon derived from Dillenia Indica peels was evaluated. The adsorption of DCF was performed in a continuous process. The findings showed that the adsorption of DCF was favorable at a lower flow rate, greater bed height, and initial DCF concentration, with the highest removal percentage of 44.93%. To assess the characteristics of the breakthrough curve of DCF, the adsorption data were used to match three distinct adsorption models, namely, Boharts and Adam, Yoon-Nelson, and Thomas. The breakthrough results were well-fitted with these models, as the values of R2 for all models and parameters were higher than 0.88. Thus, it was concluded that the activated carbon from Dillenia Indica can effectively remove DCF from an aqueous solution.
      5  31
  • Publication
    Anaerobic co-digestion of different types of cow dung with food waste
    (Universitatea Gheorghe Asachi din Iasi, 2023)
    Irnis Azura Zakaria
    ;
    Nur Adlina Mohd Hilmi
    ;
    Muhd Fakhrul Samah
    ;
    Zaki Abdul Aziz Mh Daud
    ;
    Madalina Boboc
    The value of manure as a source of clean energy can be increased through the conversion of animal waste into energy, which can also reduce the negative effects that animal waste disposal has on the environment. Anaerobic digestion (AD) is a potential bioprocess for the utilisation of waste biomass and the conservation of energy. It is also an alternative method of energy recovery and waste treatment that produces biogas, which can be used to generate either electricity or heat and is a byproduct of the digestion process. In this study, different types of cow dung in terms of nutritional processes (grass: bran); 100 % grass, 95 % grass: 5 % bran, and 80 % grass: 20 % bran were taken for anaerobic co-digestion with food waste. The purpose of this study is to investigate the production of biogas as well as the properties of anaerobic co-digestion using different types of cow dung under mesophilic temperature (37°C). Biogas production was measured by the water displacement method. The pH value, Organic Matter (OM) content, C/N ratio, and Volatile Acid (VA) were recorded throughout the experiment. Samples of 100 % grass accumulated the highest biogas production (1250 ml) followed by samples of 80 % grass: 20 % bran (1080 ml) and samples of 95 % grass: 5% bran (780 ml) between the 20th and 23rd days. This shows the sample of 100 % grass-feeding has a better performance on biogas production among the samples.
      16  2
  • Publication
    Analysis of air pollution in Malaysia: implications for environmental conservation using granger causality and pearson correlation
    (Universitatea Gheorghe Asachi din Iasi, 2025)
    Zulkifli Abd Rais
    ;
    Norazrin Ramli
    ;
    Hazrul Abdul Hamid
    ;
    Norazian Mohamed Noor
    ;
    Ahmad Zia Ul-Saufie
    ;
    Mohd Khairul Nizam MAHMAD
    This study investigates the relationships between air pollutants (PM₁₀, SO₂, NO₂, O₃, CO) and meteorological factors (temperature, relative humidity, wind speed) across five states in Malaysia: Seberang Perai, Shah Alam, Nilai, Larkin and Pasir Gudang. Using time-series data from 2017 to 2021, we applied Granger causality and Pearson correlation to explore the predictive relationships and linear associations between these variables. Granger causality provided insights into temporal precedence, revealing significant predictive relationships such as temperature Granger-causing PM₁₀ and O₃ in Nilai and Shah Alam. Meanwhile, Pearson correlation highlighted strong linear relationships, such as the positive correlation between PM₁₀ and wind speed in Shah Alam and the negative correlation between humidity and O₃ across several stations. By comparing both methods, we show how combining Granger causality with Pearson correlation can enhance environmental modelling, offering a comprehensive approach to air pollution prediction. This integration provides robust insights into the dynamics of air quality, which are critical for developing effective pollution control strategies.
  • Publication
    Analysis of short time period of operation of horizontal ground heat exchangers
    ( 2015)
    Salsuwanda Selamat
    ;
    Akio Miyara
    ;
    Keishi Kariya
    Ground source heat pump (GSHP) systems have been proven to have higher efficiency compared to conventional air source heat pump systems for space heating and cooling applications. While vertical ground heat exchangers (GHE) are favorable in GSHP installation, this type of configuration requires higher capital costs as opposed to horizontal configuration. Numerical simulation has been used to accurately predict the thermal performance of GHE. In this paper, numerical analysis of thermal performance for slinky horizontal GHE loops in different orientations and operation modes is discussed. It was found that the loop orientation is not so important due to the little effect it has on thermal performance. While the mean heat exchange rate of copper loop increases 48% compared to HDPE loop, the analysis supports the common claim that heat exchange rate is predominantly limited by the thermal conductivity of the ground. With the same amount of circulation work, the mean heat exchange rate increases by 83%–162% when operated in parallel loops operations. The performance in these operations can be further optimized to 10%–14% increase when spacing between adjacent loops was provided. The spacing helps to minimize interference of heat flow that would penalize the overall thermal performance.
      2  21
  • Publication
    Assessing the concentration, distribution and characteristics of suspended microplastics in the Malaysian indoor environment
    (Elsevier B.V., 2025-01)
    M. Dewika
    ;
    Kalaimani Markandan
    ;
    Shalini Nagaratnam
    ;
    N. Ahmad Irfan
    ;
    Muhammad Amirul Aizat Mohd Abdah
    ;
    J. Nor Ruwaida
    ;
    Sara Yasina Yusuf
    ;
    Mohammad Khalid
    This study examines the concentration, distribution, and characteristics of suspended microplastics (MPs) across various indoor environments in Malaysia, including offices, classrooms, landed homes, and apartments. Over a six-week period, MPs were collected using a vacuum pump and analyzed through gravimetric analysis, stereomicroscopy, and Raman spectroscopy. The results revealed significant variability in MPs concentrations among different locations, with fibers identified as the predominant morphological type. The average counts of MPs in the respective environments were found to be 599 ± 182 in offices, 399 ± 52 in classrooms, 505.17 ± 203.78 in apartments, and 515 ± 134 in landed homes. Statistical analysis indicated no significant differences in MPs counts across the sampled locations. Fibers were consistently the most prevalent shape, followed by films and foams. The MPs were predominantly transparent, with sizes ranging from 101 to 500 μm. Notably, the estimated daily intake (EDI) of MPs was significantly higher in residential settings compared to offices and classrooms, raising potential health concerns regarding prolonged exposure. These findings underscore the pervasive presence of MPs in the Malaysian indoor environment and emphasize the urgent need for further research to identify their sources, assess health impacts, and develop effective mitigation strategies.
  • Publication
    Assessment of moisture resistance and bonding behavior of cup lump rubber modified asphalt mixture containing wax-based surfactant
    (Institute of Physics, 2025-01-15)
    Zainiah Mohd Zin
    ;
    Mohd Rosli Mohd Hasan
    ;
    Azura A Rashid
    ;
    Muhammad Munsif Ahmad
    ;
    Tracy Leh Xin Wong
    ;
    Hui Yao
    The present study evaluates moisture induced damage potential using a sessile drop method and a pneumatic adhesion tensile testing instrument (PATTI). The bonding behavior of the aggregates (granite and limestone) and cup lump rubber modified asphalt binder (CMB) with wax-based surfactant (WS) was evaluated. The results revealed that the granite aggregate exhibited a higher work of adhesion compared to the limestone. In the dry condition, the addition of more than 0.15% WS to the CMB reduced the work of adhesion and the bonding strength. Using the sessile drop method, the moisture resistance of the limestone aggregate with the CMB and WS was enhanced, but the bonding strength was reduced. The incorporation of WS reduced the surface free energy (SFE) regardless of the aging conditions and made the aggregate surface more hydrophobic for the increased interfacial adhesion. Incorporating WS in the CMB improved the work of adhesion under the wet condition, thus indicating that WS is an effective anti-stripping agent. Considering its comprehensive properties in the CMB, the amount of WS should be limited to 0.15%.
  • Publication
    Assessment of the suitability of ceramic waste in geopolymer composites: an appraisal
    ( 2021)
    Ismail Luhar
    ;
    Salmabanu Luhar
    ;
    Mohd. Mustafa Al Bakri Abdullah
    ;
    Marcin Nabiałek
    ;
    Andrei Victor Sandu
    ;
    Janusz Szmidla
    ;
    Anna Jurczyńska
    ;
    Rafiza Abdul Razak
    ;
    Ikmal Hakem A Aziz
    ;
    Noorina Hidayu Jamil
    ;
    Laila Mardiah Deraman
    Currently, novel inorganic alumino-silicate materials, known as geopolymer composites, have emerged swiftly as an ecobenevolent alternative to contemporary ordinary Portland cement (OPC) building materials since they display superior physical and chemical attributes with a diverse range of possible potential applications. The said innovative geopolymer technology necessitates less energy and low carbon footprints as compared to OPC-based materials because of the incorporation of wastes and/or industrial byproducts as binders replacing OPC. The key constituents of ceramic are silica and alumina and, hence, have the potential to be employed as an aggregate to manufacture ceramic geopolymer concrete. The present manuscript presents a review of the performance of geopolymer composites incorporated with ceramic waste, concerning workability, strength, durability, and elevated resistance evaluation.
  • Publication
    Assessment of time series model for predicting long-interval consecutive missing values in air quality dataset
    (Penerbit Akademia Baru, 2025)
    Daniel Kim Boon Bong
    ;
    Norazian Mohamed Noor
    ;
    Ahmad Zia Ul-Saufie
    ;
    Faizal Ab Jalil
    ;
    György Deák
    Air pollutant concentration in Malaysia is continuously monitored using the Continuous Ambient Air Quality Machine (CAAQM). During the observation phase by CAAQM, some air pollutant datasets were detected missing due to machine failure, maintenance, position changes and human error. Incomplete datasets especially with the longer gaps of consecutive missing observation may lead to several significant problems including loss of efficiency, difficulties in using some computational software and bias estimation due to differences of observed and predicted dataset. This study aim evaluates the performance of the time series method i.e. Auto Regression Integrated Moving Average (ARIMA) for filling long hours of missing data in an air pollution dataset. The dataset of PM10, SO2, NO2, O3, CO, wind speed, relative humidity and ambient temperature for Pegoh and Kota Kinabalu in 2018 were used for analysis. Monte Carlo Markov Chain (MCMC) and Expectation-Maximization (EM) were employed to compare with ARIMA's effectiveness in filling the simulated missing gaps in air quality dataset. Existing missing data in the raw data were pre-treated and then simulated into 5%, 10% and 15% of missing data ranging from 24-hour to 120-hour intervals. The performance of the imputation approach was assessed using Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Prediction Accuracy (PA) and Index of Agreement (IA). Overall, the Expectation-Maximization technique was selected the most effective at filling in simulated long gaps of missing data of air pollutant dataset with the range of IA from 0.74 to 0.77. In contrast, the ARIMA approach performed poorly in this research with range of IA value of 0.44 to 0.48. This was because of it requires past time-series data to generalize a forecast or impute missing data, hence, the forecast becomes a straight line and performed poorly at predicting series with long hours of missing observation.
  • Publication
    Bridging the gap between health and safety performance and owner’s satisfaction in construction projects adopting pro-environmental construction practices: role of economic performance
    (Springer, 2023)
    Hilary Omatule Onubi
    ;
    Manuel Carpio
    ;
    Fatin Umaira Muhamad Azian
    ;
    Pirmah Binwai
    The satisfaction of clients/owners, though very important as a determinant of construction project performance, has often been given very little attention in pro-environmental-related studies. To this end, this study’s aim is to determine how owner’s satisfaction (OS) can be realized via health and safety performance (HSP) and economic performance (EP) on construction projects that adopt pro-environmental construction practices (PCP) in Nigeria and to determine how the impact of HSP on OS can vary contingent on the level of EP. This study’s aim was realized through data obtained from a survey of 249 construction projects and analyzed by adopting the partial least squares structural equation modeling (PLS-SEM) technique. The results of this study signify that HSP has a significant positive effect on OS; the nexus between HSP and OS is partially mediated by EP, while EP moderates the HSP–OS link with high EP producing the stronger effect. The practical contributions of this research emanate from the fact that its findings show that the existing gap between the level of HSP and OS is partly due to EP. Also, projects with high EP have a greater influence on the HSP–OS relationship. Therefore, to bridge the gap between HSP and OS in construction projects that adopt PCP, due attention should be given to EP.
      9  13