Monitoring the state of civil engineering infrastructure is critical for a country’s economic development since structures with long service life and timely maintenance have lower reconstruction costs. Crack occurrence is the most important element that influences the performance and lifespan of civil infrastructures like bridges and pipelines. As a result, several fracture detection and characterization approaches have been explored and developed in the domains of Structural Health Monitoring (SHM) throughout the last few decades. The major goal of implementing the Internet of Things (IoT) paradigm is to enable the Internet-based connectivity extension of various typical SHM devices. As a result, connected devices can communicate and process data, opening new possibilities in the design of acquisition systems in various disciplines of research and engineering. The researchers have extended the application of the IoT paradigm to the SHM crack detection because of the advances, ensuring that the tests done in this framework can produce good results with promising future improvements. Thus, this paper reviews structural crack detection based IoT for SHM as reported by previous research in the literature. The strengths and limitations of current systems are discussed. This paper is aimed to serve as a reference for crack detection and characterisation researchers as well as others who are interested in SHM in general. In addition, several case studies on real structures, as well as laboratory experiments for monitoring structural crack health of civil engineering structures, are also presented.

Keywords : Structural crack; structural health monitoring; sensors; internet of things

Floods and landslides, which cause significant loss of human life and economic loss, are the most reported catastrophic events worldwide. The Geographical Information System (GIS) has been recognized as one of the most effective tools in disaster related analysis. Therefore, this article uses GIS to review the development of landslide and flood research for the past 20 years. The main elements in this review are to scrutinize the trend and scope of studies related to disaster mapping around the globe. Amongst the criteria reviewed are; details of the study area, articles that received many citations, journals with high Impact Factor scores, scope breakdown based on single and multi-hazard analysis and the theme of the study. The methodology used in this Systematic Literature Review is based on the PRISMA guidelines. Results from the review found that studies related to disaster mapping are increasing every year. This trend is influenced by data availability, efforts to produce better disaster management, frequent disaster occurrences due to climate change and evolution of GIS to analyse spatial data. Nevertheless, articles related to multi-hazard analysis are still limited, and this study suggests conducting and publishing more studies related to multi-hazard assessment in the future. This review also shows that GIS has been used widely for various types of application in disaster analysis. Articles on disaster risk assessment have been the most common. This review will help other researchers in the field of disaster management to better understand the current trend of studies related to disaster mapping.

Keywords: Disaster; disaster risk management; GIS; flood; landslide

Pipelines and risers are major transportation of oil and gas. These components are often exposed to extreme marine environmental conditions that can cause pipelines to fail due to corrosion. Hence, epoxy grouts are used as a coating material on the surface of pipelines and risers for supporting the pipe structure and corrosion prevention. In this case, the efficiency of epoxy grout is important in pipeline rehabilitation. Research on the adaptation of seawater, temperature, and epoxy grouts is carried out to determine the changes in mechanical and thermal properties of the material. The preparation of epoxy grouts was prepared with a mixture of epoxy resins, epoxy hardeners, and aggregates. After the sample compounds have been flattened, the mixture will be put into the mold. The seawater aging process was performed for seven days before conducting laboratory experiments. After the seawater aging process, there were physical changes on the surface of the epoxy grouts which are the epoxy grout become harder and there were voids that can act as stress concentration points that may cause micro-crack on the specimen. Next, tensile (ASTM 638) experiments were performed at different temperatures of 27°C, 40°C, 52°C, 72°C, 80°C and 100°C while the result of compression experiment is based on the literature critique of past journals. Based on the result, the young modulus and ultimate tensile strength of the epoxy grouts are decreased with increasing temperature. The increment of temperature causes the epoxy grouts to become weaker due to the changes in the polymer matrix structure of the epoxy grouts which lead to the failure at low load and shortens the life of the material. In addition, epoxy grouts are amorphous materials where the glass transition temperature determine the mechanical and physical properties of epoxy grouts. Therefore, the results of the study found that the epoxy grouts changed its mechanical properties from brittle to ductile when the temperature is at 72°C. From the comparison between samples immersed and not immersed in seawater, there is a decrease in Young’s modulus, ultimate tensile stress and strain due to the effect of seawater reaction. In conclusion, the increment in temperature and seawater adaptation factors affect the strength and durability of epoxy grouts.

Keywords: Epoxy grout; mechanical and thermal properties, seawater adaption, elevated temperature, tensile and compression test

Coarse aggregate (CA) is a major ingredient of the concrete, constituting around 60-75% of total concrete volume in a conventional mix design. The demand for CA is drastically growing, resulting in the diminishing of natural resources, and its extraction demands heavy machinery input, which triggers additional environmental issues. This research investigates the mechanical behavior of green concrete by partially substituting CA with wasted coconut shells (CS) and over-burnt bricks (OB). CS replaces at 5%, 10%, and 15% during the mix design, whereas OB substitutes at 20%, 25%, and 30%. Total 216 specimens were cast in the form of cubes, cylinders, and beams. It was observed that the workability and density of concrete decrease with increasing CS and OB. The compressive strength, split tensile strength, and flexural strength of the specimen decreased in both substitutes with the increasing amount of substituting materials when used individually. However, an increment is found in the mechanical behavior of green concrete when CS and OB were both used at 5% and 20% replacement, respectively. The study has multiple implications for casting eco-friendly or green concrete, such as the reuse of waste materials, reducing the carbon emissions obtained from the extraction of CA, and preserving the natural resources.

Keywords: Coarse Aggregates; coconut shell; over burnt brick; mechanical behaviour; concrete; environment

Bicycle-sharing has become one of the most popular transportation modes especially for short-distance travel and supports sustainable transportation. This concept is relatively new in Malaysia and cycling culture is not widely spread among the community. This has provided growing difficulties and challenges to the use of bicycle-sharing service especially in the university campuses. The increasing use of motorized vehicles and decreasing use of bicycles has not only affected bicycle-sharing services but also the environment of the campus. Thus, the aim of this study is to identify the significant factors affecting the use of UniRide bicycle-sharing and the existing level of use of bicycle-sharing in International Islamic University Malaysia (IIUM), Gombak Campus. The data required for this study were collected by using an online questionnaire survey targeting the students who live on-campus. The collected data were analysed by using both univariate and bivariate analysis methods. The results of the analysis show that most of the respondents felt that convenience and bicycle infrastructure are the main factors that affect the use of UniRide bicycle-sharing in IIUM. Most of the respondents also stated that riding bicycles on a dedicated and exclusive bicycle lane would enhance the safety of the bicycle users. Few recommendations to improve the existing UniRide bicycle-sharing service on-campus were formulated.

Keywords: Bicycle-sharing; bicycle use; bicycle infrastructure; bicycle safety; university

The load-deformation observation under the footing is essential for foundation design. Either experimental methods or numerical modelling generally determines this phenomenon in engineering practices. This study determined the settlement of shallow foundations on Multi-layer soil profile numerically. The settlement behavior was investigated through numerical modelling with Plaxis 2D. This study site was Jamshoro region, located in province Sindh, Pakistan. From the geotechnical investigation, the soil of Jamshoro region consists of a combination of different soils, mainly shale and limestone. This type of soil shows common challenges for the serviceable and sustainable design and construction of structural foundations. The standard penetration test conducted accompanied by other geotechnical tests on shale and limestone to determine the input parameters for the model and observe the soil profile. The Mohr-Coloumb model used for shale and linear elastic for limestone. The settlement of the foundation is attended by varying the limestone layer’s depth. In this research, the settlement reduced under the footing by increasing the thickness of the limestone layer. The study observed that stiffness of lower layer significantly reduces the settlement of shallow foundation. Therefore, the effect of lower layer should be considered for the designing of foundation on multi-layered soil.

Keywords: Plaxis; shale; settlement; layered soil; numerical modelling

In this research, the three-dimensional elastic wave equations with variable coefficients (i.e. propagate through inhomogeneous media) are solved with the application of the Fourier transform in the spatial coordinates. The wave equation is coupled variable coefficients PDEs whose solutions may have significant in engineering applications. The method utilizes the second order ODE as the baseline for obtaining the complete solution. The solution of second order ODEs is expressed in one integration because the variable coefficients are broken down into several functions and resulted in first order reduction. Moreover, the coupled equations are performed by the order reduction of the higher order ODEs into the second order. The extended procedure for integral equation is implemented for the solutions from the transformed wave equations to generate the explicit expression. It is shown that the proposed method of integral evaluation is resulted in finding the roots of polynomials. Hence, it is concluded that the solvability of the elastic wave equations is ensured by the proposed method.

Keywords: Wave equation; Inhomogeneous media; Reduction of order; Integral evaluation; Reduction of polynomial order

Activated tungsten inert gas welding (ATIG) welding is a new approach to Tungsten Inert Gas (TIG) welding that has the potential to improve weld penetration. This paper investigates the effect of micro and nanoparticle size oxide flux during TIG welding of Hastelloy C-22. The effect of SiO₂ and Al₂O₃ oxide fluxes in terms of particle size and thermal stability on surface appearance, bead geometry, and microhardness of the fusion zone of hastelloy C-22 is investigated. The surface appearance of ATIG weld has a better appearance using nanoparticle size oxide flux when compared with the same micro size oxide flux. A slag layer produced by nano flux decomposition during TIG welding is very less compared to micro oxide fluxes. Nanoparticle SiO₂ flux has the potential to improve weld penetration and depth to width (D/W) ratio in the generated weldment when compared to microparticle SiO₂ flux during TIG welding Process. When nanoparticle Al₂O₃ is used in TIG welding, weld penetration or the D/W ratio do not increase significantly. Due to the high voltage produced at the same arc length, TIG welding with nanoparticle SiO₂ flux produces a high heat input. Furthermore, higher arc temperatures produce by nanoparticle fluxes at the arc column, resulting in increased penetration depth.

Keywords : ATIG; Flux; Slag; Penetration depth; weld bead width

For years, geotechnical engineers have been concerned about expansive soils. Expansive soils are characterized by large volumetric changes related to variations in moisture content. Variations in soil water content may take place naturally during seasonal changes or maybe manmade caused by dewatering activities. The quantity of shrinkage and swell is influenced by numerous parameters, including the quantity of minerals clay in the soil, moisture content, dry density, and climate change. In most countries, numerous structures, including pavements and buildings, are damaged as a result of this shrinkage/swelling. Several ground improvement techniques are available for stabilizing expansive soil to modify its engineering performance. These methods include soil replacement, mixing with chemical additives, and soil reinforcement. The present study expressions the effect of nano-lime (i.e., 0.1, 0.3, 0.5, 0.7, 1.0, 2.0 and 3.0%), and lime (1, 3, 5, 8, and 10%), as chemical additive to improve clayey soil (i.e., illite and kaolinite). The effect of nano-lime and lime were investigated using Atterberg’s limits tests. The Atterberg limits were screening significant changes in the proportion of additional nano-lime and lime. The results show that less amount of nano-lime (1% and 2% for illite and kaolinite respectively) decreased the plastic limit, while for lime it was reported 8% for illite and 5% for kaolinite respectively. In conclusion, less quantity of nano-lime (1-2%) is able to improve soil parameters.

Keywords: Nano-lime; lime; illite; kaolinite; chemical stabilization

Currently, the solar PV power extraction technology is undergoing significant improvement. Towards this, the paper proposed the design for a photovoltaic (PV) array and the output performance of a photovoltaic system under the influence of irradiance. To achieve this, the design for improved incremental and conductance fast tracking INC -FI based MPPT technique for solar PV system has been presented. The purpose of employing the improved INC -FI technique is to improve the efficiency of the system. The accuracy and performance of the proposed INC -FI method was increased due to its better tracking capability by utilizing variable ΔD for tracking the MPP in comparison to the conventional INC method at variable temperature while keeping the irradiance constant. Further, the results of the proposed method were compared with the conventional method where the INC -FI based technique outperforms the conventional INC method in terms of better accuracy. For the irradiance with 800w/m2, the achieved MPPT efficiency was 58.21 for conventional method and 80.53 for the improved technique. It was also noted that the tracking efficiency of the conventional method was 84.39 as compared to 99.92 for the proposed INC -FI technique in terms of MPPT efficiency at the irradiance of 1000w/m2. Furthermore, the improved method delivered fast tracking ability of the MPPT system with a time of less than 10 s(approx.). The MATLAB Simulink platform was utilized for designing the proposed technique. In future, the proposed INC based technique would be implemented on hardware for better outcomes and validation.

Keywords: Maximum power point; photovoltaic module array; renewable energy; matlab/simulink; INC – FI method

Change in activity patterns and travel behaviour were seen worldwide as a response to the COVID-19 pandemic. This is mainly due to the restrictive measures imposed by the government and perception of own safety or commitment in reducing the spread of the disease. However, with or without the restrictive measures, people still have various needs to travel. Thus, this study was initiated to understand the changes in travel behaviour due to the COVID-19 pandemic. An online questionnaire survey, including questions related to purpose of travel, transport mode choice, distance and frequency of trip was conducted. Findings from this study revealed that there is a significant change in activity pattern and travel behaviour, before and during the COVID-19 pandemic. Based on the 460 responses received, it is known that mode shifts, from public transportation to private vehicles, occurred mainly due to pandemic related concerns. This study reveals that people perceived public transportation as a potential risk for exposure of the COVID-19 virus, while private vehicles, bicycles and walking are viewed as the safest mode of transport during the pandemic. Gender, age group, vehicle ownership, marital status and purpose of travelling had significant impact on the mode choice during the pandemic. Based on these findings, it is hoped that rail and bus transport service providers will be able to plan measures and further encourage the usage of the rail and bus transport services post-pandemic.

Keywords: COVID-19; pandemic; transportation; mode choice

Distribution of wealth of a deceased person among the heirs is a critical and complicated problem in Islamic jurisprudence system. In a Muslim society, the demand of a wealth calculation system is very high and plays a pivotal role in day-to-day life of Muslim families. In this paper, we propose a structured and well-defined software solution that employs structured software engineering approach using Data Flow Diagram (DFD), structure chart and program description language (PDL). The proposed system distributes shares among the heirs based on Islamic rules. Many such systems have been built by different govt agencies of different Muslim majority countries. Many of those systems are error prone and are not well defined from the software engineering perspective. In many cases, the software architecture of such systems is undisclosed and their applicability in many complex deceased-heir relationship provides wrong calculation. The proposed solution on the other hand, makes the successful use of software engineering approach to interpret Islamic Inheritance rules in a more manageable, scalable and maintainable fashion. The system is rigorously tested on different complex scenarios and the results are verified by Muslim family lawyers. The system is developed using C programming language and we make the source code open.

Keywords: Structured analysis; structured design; DFD; structure chart; Islamic inheritance system

The degradation of radio wave signals in the frequency band more than 10 GHz is due to the factor of high rainfall intensity in tropical climates.Therefore, the prediction of rainfall attenuation on the propagation of using 1 minute intgration time of rainfall rate is important. This study uses 60 minute intergration time of rain rate ,observed at 10 station of the Deparment Irrigation and Drainange Malaysia through out Malaysia in a period of 3 years fro 2017. The Segal’s model was selected as the 1 minute integrated rainfall data conversion method due to the small probability error as well as the suitability for the tropics. The worst month rainfall distribution forecast was implemented by choosing the ITU-R model P.184-5. The result of this study has found that Sarawak showed the highest rain rate value compared to the Peninsular Malaysia. Apart from that, the worst month rain rate forecast also found the value of worst month coefficient, Q1 and β proposed by the International Union Telecommunication (ITU-R) model are not suitable for Malaysia where the new parameter value for Q1 and β were obtained so that better estimation for the worst month statistic could be published. The results of this study are not only in preparation for flooding but can also be used as a guideline in designing a more efficient satellite communications system.

Keywords: Integration time; rainfall rate distribution; worst month; Q factor

Two standards that are widely used by many countries in designing offshore gas transmission pipelines are American Standard – ASME B31.8, Gas Transmission and Distribution Piping Systems and Norwegian Standard – DNVGL-ST-F101, Submarine Pipeline System. A thorough understanding of these standards is vital in determining optimal pipeline design to ensure pipeline integrity for safe and sustainable operations, as well as striving for economic efficiency. This study aims to evaluate the wall thickness required for pipeline designs using American and Norwegian pipeline standards under different steel grades and water depth conditions. Pipeline costs are then compared for both standards at each water depth condition for commercial evaluation. Through this, the optimal pipeline standard for wall thickness design can be determined. Mathcad software was used for data analysis in accordance with the standards mentioned and all design requirements including pressure containment, collapse, and propagation buckling. Ultimately, the American Standards was able to provide a total cost that was 2.5% lower than the Norwegian Standard for a pipeline project with a combination of shallow, medium, and deepwater depths along its route. However, a combination of Norwegian Standards for medium and deepwater depths and American Standard for shallow water depth can further reduce total costs to 2% compared to only using the American Standard. This study highlights the importance of considering several design standards for a pipeline project instead of strictly adhering to a single standard for better technical and commercial benefit.

Keywords: Pipeline Engineering; wall thickness design; deepwater

The recent advancement of synchrophasor measurements technology in the conventional power grid can monitor and control the state variables of the network very accurately at a high sampling rate in real-time. The complete observability of system states can be achieved through the Phasor Measurement Unit (PMU). The inclusion of a zero injection bus (ZIB) optimized the total number of PMU requirements for complete observation of the synchrophasor network. The communication channels between measurement devices and control centers are highly vulnerable to cyber threats. Thus, an anomaly that occurs with PMU devices during a cyber-attack can affect the system’s reliability. Therefore, monitoring the reliability of the synchrophasor network has become essential for healthy power operation. Synchrophasor measurement technology can enhance wide-area surveillance and security functionality. However, the dependability of such technologies in the context of information network accessibility has yet to be investigated in a coherent model. Growing electric grid defence levels to mitigate the impact of cyber-attacks is essential. The cumulative effect of synchrophasor network observability and reliability is discussed in this paper by optimizing the number of PMUs deployed and the interruption load that occurs during an anomaly with PMU while taking ZIB into account.The backup PMU deployment modeling is also presented to secure the reliability and observability of the grid network during an anomaly occurs with PMU. The indices, Interrupted Load Probability Index (ILPI) and Expected Demand Not Supplied (EDNS), are used to evaluate the reliability of synchrophasor grid networks by integrating the state probability of PMU unavailability due to cyber intrusion.

Keywords: ZIB; optimal PMU deployment; synchrophasor grid observability; reliability indices; cyber intrusion

M303 is a corrosion resistant martensitic chromium steel offering excellent toughness, corrosion, and wear resistance, characterized by improved machinability and polish ability. It is widely utilized in industries such as in mould and die making, machinery and automotive equipment, bearing housing, and tooling. Recently, this material has also been used in locomotive bearing housing. This paper presents surface roughness achieved in the turning process of M303 in dry cutting condition using coated and uncoated carbide tools. The turning parameters included a high cutting speed regime (260-340 m/min) and feed rate at 0.1-0.2 mm/rev, suitable for the finishing process. The experiment was conducted according to the Taguchi method (L18). Average surface roughness (R_a) was in the range of 0.395-1.356 μm, in which a mirror finish was achieved for certain cutting conditions that could eliminate the grinding process. Results of surface roughness were analysed using Analysis of Variance (ANOVA) for linear models and revealed that feed rate is the main significant factor contributing to surface roughness, followed by type of cutting tool, and cutting speed. These findings show that good and dition, therefore it is recommended to eliminate the acceptable R_a values for M303 turning are obtained in dry con use of flooding condition as normally practiced in the industry.

Keywords: Surface roughness; high speed turning; M303; dry cutting

The beam-column joint is an important component of Reinforced Concrete (RC) structures because its design and detailing are critical to the safety of these structures under seismic loading. In recent decades, structural behaviour of beam-column joints has been widely explored. To better understand the behaviour of beam-column joints, researchers have conducted experiments and provided analytical and experimental solutions. The seismic behaviour of beam-column joints with and without Glass Fibre Reinforced Polymer (GFRP) when subjected to quasi-static lateral cyclic loading was compared in this research using two specimens. The first specimen is a typical RC exterior beam-column joint without GFRP while the second specimen is RC exterior beam-column joint that is pre-installed with Glass Fibre Reinforced Polymer (GFRP) using Near-Surface Mounted (NSM) technique. The specimens were evaluated to a drift of 2.0% under quasi-static lateral cyclic loading. There were two cycles in each drift. Based on the amplitudes of both specimens, it can be seen that the amplitude of beam-column joint with GFRP is lower than the beam-column joint without GFRP. This suggests that the presence of GFRP reduces the intensity of the loading. This study also discusses the energy dissipation and equivalent viscous damping on both specimens. During the experiment, each crack, void between the concrete, and spalling of concrete fragments were carefully monitored. Visual observation during the experiment shows that severe cracking is evident on the inner part of the structure in both specimens. Therefore, a new location of GFRP-NSM would be suggested for a future experiment.

Keywords: RC Exterior Beam-column joint; Quasi-static lateral cyclic loading; Glass-Fibre Reinforced Polymer (GFRP); Near-Surface Mounted (NSM); Amplitude; Energy dissipation; Equivalent viscous damping

Biocomposite from kenaf reinforced polylactic acid (Kenaf/PLA) has the potential to replace a synthetic reinforcement and matrix in polymer composite applications. Kenaf is well known as a natural fiber that can be replaced with synthetic fiber and reinforced with synthetic resin, whether thermoset or thermoplastic. An increase in environmental impact drives increased usage of a biodegradable polymer such as PLA in the application of biocomposite. However, moisture uptake from the humidity and elevated temperature exposure during fabrication of composite is mostly a factor that affects the properties of biocomposite. Therefore, this study aims to optimize the factors consisting of humidity exposure, temperature and time holding during hot press using the design of experiment (DOE) by Box-Behnken Design (BBD) approach. The kenaf/PLA was exposed to the humidity range from 40% up to 80% before undergoing composite fabrication. Then produce the composite using a hot press molding where the parameter consists of elevated temperature (range from 160 ^oC up to 200 ^oC) and time holding (range from 3 minutes up to 10 minutes) that possibly affects the mechanical properties of kenaf/PLA. These three factors were evaluated based on optimizing maximum results on flexural properties, where all the combination factors were assessed using DOE. Using analysis of variance (ANOVA) revealed that humidity exposure and hot press temperature are essential factors affecting kenaf/PLA flexural strength. The results indicated that the selected humidity and hot press parameters were 40 %RH, 160 ^oC press molding temperature, and a 3-minute heating duration for optimal flexural strength. The parameter will obtain 111.61 MPa of flexural strength. Implementing the chosen factor can produce the kenaf/PLA biocomposite with an optimum flexural strength of 111.61 MPa.

Keywords: Biocomposite; Kenaf; Polylactic acid, flexural properties

Austenitic stainless steel (ASS) is the most common type of stainless steel which offers excellent weldability and mechanical properties. ASS is being used for various applications i.e. automotive, oil and gas and chemical industries in which the welding process plays a prominent role. Welding process selection is the main factor that emphasizes mechanical and corrosion resistance properties in various aggressive environments. There are various corrosion occurs in ASS but intergranular corrosion (IGC) forms during welding at elevated temperatures. IGC mainly occurs at grain boundaries of structure and resulting chromium depletion due to precipitation of chromium carbide at the grain boundary. In present work pulsed current gas tungsten arc welding (PCGTAW) process was used to investigate intergranular corrosion by oxalic acid test as per ASTM A262 Practice A. Experiments performed based on Taguchi L9 using design of experiments and corrosion rates are evaluated at base metal, heat affected zone and weld zone. This work is aimed to optimize process parameters followed by regression analysis to IGC susceptibility in the weldment. In this investigation, it has been found from ANOVA and main effects plots that peak current and base current are the most significant parameters in the PCGTAW process. The results of the corrosion test revealed that heat affected zone is more susceptible to IGC. At the end, it has been observed that the optimum value of peak current, base current and frequency based on regression analysis are 100 A, 50 A and 6 Hz respectively.

Keywords: Pulsed current gas tungsten arc welding (PCGTAW); SS304L; intergranular corrosion; ASTM A262 PRACTICE A; Regression analysis

Printed circuit boards (PCBs) are the basic components of electrical and electronic devices. E-waste management is challenging to implement due to accompanying difficulties and danger. Valuable metals and copper (Cu) are primarily recycled through various methods in the treatment of waste PCB. A large number of non-metals materials in PCBs are disposed of through combustion or in landfill, resulting in secondary pollution and resource waste. To reduce the amount of waste non-metallic PCB (NMPCB) and the influences toward environment, recent studies focused on the usage of NMPCB as filler to replace raw material. NMPCB as filler seems to have a good interaction with the raw materials and thus can enhance the strength of the newly formed product. In our study, we focused on developing new NMPCB added with waste NMPCB. Commercial NMPCBs are often a flat laminated composite comprising non-conductive substrate materials. Hence, pre-treatment methods to remove metals, especially Cu, must be investigated. The present study attempted to remove the Cu layer on PCB by using chemical and physical methods. The untreated and Cu removed PCB residues were characterized using X-ray diffraction (XRD), scanning electron microscopy, and infrared spectroscopy (FTIR) for the determination of structural and functional groups and hydrophobicity test. XRD analysis indicated that the Cu in untreated PCB was successfully removed using physical and chemical methods.

Keywords: E-Waste; Recycling; Printed circuit board; Non-metallic; Copper etching

Micro-powder injection molding (μPIM) is a modification of powder injection molding (PIM) process and a globally recognized manufacturing process route that can be used largely to produce sophisticated micro-sized components using a wide range of metals and ceramics. The demand of μPIM process is currently increasing in various applications in telecommunication, electronics, aerospace, biomedical, and automotive industries. In this research work, sintering at three different temperatures between 1250 °C and 1350 °C at a heating rate of 10 °C/min with a dwelling period of 3 h on micro-injection molded and debound (solvent and thermal) micro-sized components of stainless steel 17-4PH (SS 17-4PH) was carried out. After the sintering operation, defect-free SS 17-4PH micro-specimens were achieved. The relative density, which is referred to as an important physical property of SS 17-4PH micro-parts, increased substantially from 95.3% to 97.5% when the sintering temperature was enhanced from 1250 °C to 1350 °C. The maximum shrinkage of 12.9% was observed in micro-sized specimens at the sintering temperature of 1350 °C. After the completion of sintering process, the findings revealed that SS 17-4PH micro-parts can be produced successfully on the grounds of μPIM process employing the SS 17-4PH feedstock with powder loading of 69 vol.%.

Keywords: Micro-powder injection molding; SS 17-4PH; sintering; physical properties

An emergency route is a route designed for human use to save themselves from dangerous situations. However, if it is considered trivial, this has unknowingly led to an increase in accidents. The provision of emergency routes on a community scale in indoor areas in terms of time is rarely discussed in emergency evacuation studies. This study aims to investigate the emergency route in the building due to the environmental factors of the closed area and the arrangement of office equipment. The method of this study is divided into two sub-sections, namely data preparation and data analysis process. Demographic data and physical interactions were used as the selection of walking speed criteria while the use of geometric data to see the actual plan route position of the building. 3D building models are built through Revit software and then converted to industry foundation classes format (.IFC) and then to multipatch shapefile (.shp) to be integrated into ArcGIS software. This is intended for the use of the data analysis process that is to build a geometric network model (GNM). GNM is designed to determine the safest and shortest routes by taking into account a variety of obstacles based on the scenario conditions. The findings shows that the evacuation time is influenced by the speed and distance of the route. 80% of the safest route selection takes a long time compared to the shortest route, while 20% is the same distance and time for the shortest and safest route because route selection is the same. The findings able to be used as a reference and guideline to determine the selection of emergency routes, especially in complex buildings.

Keywords: Emergency Route; Geometric Network Model (GNM); Industry Foundation Classes (.IFC); Safest Routes; Shortest Routes

Acetic acid (AA) is considered an inhibitor in the oil palm frond (OPF) biomass hydrolysate solution. It can reduce the microorganism activity during sugar fermentation using OPF solution. In the current study, a hollow fiber supported liquid membrane (HFSLM) system using hybrid polyethersulfone-graphene membrane support and organic liquid membrane phase of 0.5 M tri-n-octyl amine carrier in a 2-ethyl-1-hexanol diluent was used to remove the AA. The liquid membrane impregnation time and the flow operation modes of the feed and strip phases in the HFSLM configuration were investigated. Mode I was operated with the feed phase flow inside the hollow fiber (HF) lumen and the stripping phase flow at the shell side. In mode II, the feed phase entered at the shell side and the stripping phase at the lumen of the HF support. The best liquid membrane impregnation time was 4 hours, exhibiting the highest AA removal efficiency of 80% compared to 1 and 24 hours of impregnation time. The removal efficiency of the AA was 80.1% and 42.4% using mode I and mode II, respectively, at 8 hours of the supported liquid membrane (SLM) running time. HFSLM was applied to remove AA from real OPF biomass hydrolysate. It was found that the AA concentration had reduced from 6.83 to 2.01 g/L after the SLM process. The SLM process did not affect the concentration of other components, especially sugar compounds in the OPF biomass hydrolysate.

Keywords: Supported liquid membrane; hollow fiber membrane; oil palm frond; biomass hydrolysate; acetic acid.

Aerodynamic drag of fast-moving train has significant impact on its fuel consumption and design safety. To improve aerodynamic performance, the drag forces on the train surfaces must be reduced. Train’s front-end nose design has boundless geometrical variations that can be applied for improved performance. Three geometric characteristics were used in present research: A-pillar roundness, nose length that controls its shrinking, and nose bluntness. Latin-Hypercube based random sampling method was used to determine appropriate values of these parameters for specific range. Using Computational Fluid Dynamics (CFD), a numerical approach was used to analyze train aerodynamic performance based on selected factors and operating conditions. Comparisons based on analysis of the base design and proposed design models were made and evaluated for enhanced performance. CFD analysis of the base design and iterative improvements in modified designs indicate drag reduction through change in A-pillar roundness and bluntness of nose to be 10% and 22%, respectively. The increase in nose length which controls nose shrinkage causes the drag to increase by 35%. Similarly, the boundary layer and pressure distribution on the front end of train were also considered and analyzed for performance improvement. It was concluded that the length controlling nose shrinkage of proposed train design is the key factor among the selected geometric parameters that has more influence on drag on high-speed train surface in comparison to other parameters considered. This research effort offers a modification, analysis and comparison of front-end nose geometry of high-speed train to improve aerodynamic performance and consequently fuel consumption.

Keywords: Computational Fluid Dynamics (CFD); boundary layer; train nose profile; pressure distribution; high-speed train; aerodynamic drag

Cenosphere is a component of fly ash (FA) and has been used as part of sustainable material in wastewater treatment, automotive, ceramic, and construction industries due to its properties. This research presents the first study on characterization of cenospheres from Malaysian power plants namely Jimah, Kapar and Manjung. The characterization was conducted via X-ray fluorescence (XRF), particle size analyzer (PSA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The XRF analysis consisted of oxides elements ranged from 14.70 to 22.63% (aluminum oxide, Al₂O₃), 3.78 to 13.44% (calcium oxide, CaO), 34.73 to 57.67% (silicon dioxide, SiO₂), 0.42 to 1.07% (sulphur trioxide, SO₃), 9.09 to 24.92% (iron oxide, Fe₂O₃), 3.62 to 3.67% (potassium oxide, K₂O), 1.76 to 4.24% (titanium oxide, TiO₂) and 0.16 to 0.93% (magnesium oxide, MgO). The classifications of cementitious materials by American Standard of Testing Materials were Class F (Jimah, Kapar) and Class C (Manjung). The classification represents the quality and capability of cementitious materials as cement replacement material, additive, and filler in concrete mix. The sizes of cenospheres were Kapar > Jimah > Manjung. The sizes of cenosphere were found to be larger than FA (Jimah: 2.720-49.21 μm, Kapar: 5.069-98.29 μm, Manjung: 1.084-3.986 μm). Cenospheres contained quarts (Jimah, Kapar, Manjung: 26°) and silicates (Kapar, Manjung: 45°). Ferrospheres, cenospheres, aluminosilicate-spheres, plerospheres and carbon fragments were observed. The cenosphere from Manjung showed high quality as cement replacement material, additive, and filler with 13.44% of CaO.

Keywords: Physicochemical properties; Cenospheres; XRF; PSA; XRD; SEM; Malaysian power plants

Palm oil mill effluent (POME) is a wastewater generated from palm oil industries that rich with organic and nutrients which can becomes an excellent substrate for biogas production. A comprehensive study was carried out to study the effect of different ratio of inoculum to POME substrate for biogas production. In addition, the removal efficiencies of biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal nitrogen (AN), total nitrogen (TN) total suspended solid (TSS), volatile suspended solid (VSS) were also evaluated. Bio-methane potential (BMP) was used by manipulating temperature and HRT which were set to 28-32 °C and 30 days. The BMPs were operated under different ratio of inoculum to substrate at ratio of 20:80, 30:70 and 40:60. Highest cumulative biogas yield obtained was 1990 mL in the BMP containing 30:70 (inoculum:substrate) followed by the ratio of 40:60 with 1055 mL and 20:80 with 345 mL. Maximum TSS and VSS removal efficiency were 27% and 55%, recorded in 30:70 respectively, while in 40:60 and 20:80 were 23% and 12% and 8% and 51% respectively. The removal of TN was also high at 30:70 with 79% removal. Removal efficiency of COD was in BMP of 20:80 with 54% removal while BOD removal was seen the highest in 40:60 ratio BMP. Lastly, the AN were managed to be removed about 95% in 20:80 BMP. The results obtained in this study indicated that with different ratio od inoculum to POME substrate can enhance biogas production and quality of POME prior discharge to environment.

Keywords: POME; inoculum size; methane

Renewable energy (RE) is an important addition to existing energy systems, indispensable to the sustainable development of human society now and in the future. Renewable energy is advantageous as it is clean, renewable and sustainable. Although the global power supply mainly relies on fossil fuels, as fuels are consumed and the formation cycle is extremely long, resources will gradually decrease and costs will increase accordingly. There are many types of renewable energy, and the selection of which RE should be chosen in a specific situation depends on many factors. The objective of this study is to develop a decision-making framework based on the Analytical Hierarchy Process (AHP) which covers four available renewable energy technologies in Malaysia. Through this process, the most critical issues in implementing the renewable energy systems can and have been identified which includes technology, ecological environment and market issues that must be overcome. The AHP results show that hydropower has great potential for electricity generation in Malaysia, while biomass and wind are ranked second and third respectively, and solar is ranked fourth. Nevertheless, this research had only considered four criteria with limitations in terms of the sub-criteria chosen. The accuracy of this framework may be improved if additional criteria are included and analyzed which can closely simulate the actual scenario of renewable energy development in Malaysia. Hence, through continuous optimization of the energy structure, energy security can be ensured while regional development strategies can be promoted for a balanced development of sustainable energy systems in the region.

Keywords: Decision-making framework; Analytical Hierarchy Process (AHP); renewable energy

Polygonum minus (locally known as Kesum) roots has been reported to contain bioactive sesquirtepenes compound, which is β-caryophyllene. In this study, supercritical fluid extraction using carbon dioxide was employed to investigate the effects of CO₂ flow rate (2 ml/min, 3ml/min and 4 ml/min) towards essential oil yield (EO) and β-caryophyllene yields from P.minus roots. The extraction pressure, temperature and time were fixed at 80 bar, 40^oC and 240 min, respectively. The results showed the highest amount EO obtained at flow rate 4 ml/min with 33.3% followed by flow rate 3 ml/min and 2 ml/min were 24% and 12.4% respectively. On the other hand, the highest amount β-caryophyllene was obtained at the lowest flow rate of 2 ml/min with 7.69% yield, followed by 3ml/min (1.62%) and 4 ml/min (1.54%). It can be explained that by increasing the CO₂ flow rate, it will increase the initial extraction rate and the overall extraction of EO. However, mass transfer resistance limits the amount of β-caryophyllene transported to the bulk solvents with increasing CO2 flow rate. Thus, further study is needed to overcome the mass transfer limitation and improve the overall extraction of β-caryophyllene from P.minus roots.

Keywords: Supercritical fluids extraction (SFE); CO₂ Flow rate; Polygonum minus root; β-caryophyllene

The effective utilisation of lignocellulosic biomass as fossil-based counterparts in the development of bio-based chemicals manufacturing is progressively relevant. Hence, many works are underway to shift from petrochemical industries to a sustainable lignocellulosic biomass biorefinery in lactic acid production. Malaysia is the leading country as a palm oil producer, with an enormous supply of inexpensive, renewable and non-food, yet untapped oil palm biomass resources. In this regard, oil palm fronds (OPF) rich in glucan content account for 60% of total agricultural biomass in Malaysia, which can accommodate 2 million metric tons per annum of fermentable sugar. The richness of carbohydrates in OPF serves as the key to unlocking bio-based lactic acid commercialization for future sustainable breakthroughs. This paper aims to provide insights into the exploitation of OPF as the novel feedstocks in bio-refinery processes. Special emphasis in this review is put on the technology, global demand, commercial status and future prospects of the production of second-generation lactic acid, as this process has received most research and development efforts so far. It reviews the current research attributed to the compositional analysis of OPF by primarily focusing on the National Renewable Energy Laboratories (NREL) protocol. It then focuses on the recent technological advancements of different pretreatment methods and hydrolysis for carbohydrate recovery in lactic acid production. Given with the tremendous potential, OPF can be exploited as an excellent sugar platform for the production of higher value products such as advanced biofuels, fine-platform chemicals and bioenergy.

Keywords: Oil palm frond; lactic acid; pretreatment; enzymatic hydrolysis