The use of heavy goods vehicles (HGV) has grown locally and globally. In this regard, every road user faces a high accident risk and is susceptible to traffic-related injuries and deaths. There is a substantial focus on law enforcement to prevent overloading, speeding, and illegal substance use among drivers. Nonetheless, evidence about the complex causes of HGV accidents is still scarce. Thus, this paper aims to outline the literature related to HGV study and examine factors of HGV accidents. Several factors that significantly contribute to accidents have been identified in the literature review. The study has established three main HGV accident factors with 15 sub-HGV accident factors. The Human Factor was the most dominant, while the Vehicle Factor was the least acclaimed HGV accident factor. The review also found several areas for further empirical improvements by including diverse data sources, a more extensive database, and more advanced data analysis. Moreover, technology advancements are required to capture more detailed and richer data for future studies on HGV. Future studies related to HGV accidents are essential in reducing the fatality rate in line with the Sustainable Development Goals (SDG) Goal 3 target 6, which reduces the number of individuals killed or wounded in vehicle accidents worldwide.

Keywords : Heavy goods vehicle; accident factors; road safety; road transport; commercial vehicles

The friction stir welding (FSW) is widely used in the fabrication of Aluminium alloy and other non-ferrous alloy. It has good potential to be used in major industries such as automobiles, aerospace, shipbuilding and can be used in the joining of high strength alloys. The FSW process low distortion and heat affected zone (HAZ) with fine recrystallized microstructure which leads to better mechanical properties at the weld zone and produces great stability. In this study, the different FSW parameters such as weld speed, tool rotation speed, tool tilt angle, feed per min has been discussed. The different types of tool pin profile and shoulder have also been discussed and their impacts on mechanical and microstructural properties at welded joints. Among various welding parameters the rotational speed is the most influencing parameter in FSW. Increasing the rotational speed exhibits the increase at tensile strength and is supposed to improve the mechanical properties. The most affected tool pin profile would be considered to be tapered threaded cylindrical pin profile which makes the adequate mixing of material with better flow ability and provide the fine grains at nugget zone. Comparing the FSW with other arc welding processes, it shows a wide range of environmental benefits which are noticeable such as saving in consumable materials, decrease in consumption of filler material and reduction in grinding wastes. Harmful emissions created from arc welding causes a health hazard to the welder. For achieving the high joint-strength for aerospace aluminium alloys and high temperature sustainable metallic alloys, friction stir welding will be preferred.

Keywords: Aluminium; tool design; rotational speed; welding tool speed; tool profile; mechanical properties

Solid oxide fuel cell (SOFC) can reduce the carbon footprint due to their flexibility of fuel usage by using hydrogen and light hydrocarbon as fuel to convert the chemical to electrical energy. This has made the SOFC an interesting device for renewable applications. SOFC which is able to convert the biogas produces from the water treatment plant directly to electrical energy is a reliable renewable energy application. The performance of SOFC itself can be greatly influenced by the characteristics of the biogas. This is caused by the impurities of the biogas that would degrade the internal reforming aspect of SOFC. Mainly on the anode side degradation due to the formation of carbon, sulfur poisoning, and mechanical instability. The commonly found biogas impurities from the wastewater treatment plant are Siloxanes. The compound is coming from sewage sludge digestion which is the common compound in household cleaning products and cosmetics. The presence of Siloxanes in internal reforming SOFC would lead to the formation of SiO2 which degrade the anode layer and consequently reduces the power generation of SOFC. Hydrogen sulfide and ammonia were also present in the biogas fed from the wastewater treatment plant. These contaminations also showed degradation in the SOFC of the anode. Thus, this work will discuss the contamination compound and its effect on SOFC.

Keywords: Solid oxide fuel cell; biogas; contamination; degradation

Driving vehicles has become more complex. Thus, drivers who are not engaged with any non-related driving activities, that is performing in-vehicle secondary task, are unusual nowadays. Statistics also shows the higher number of crashes come from distracted driving. In addition, currently, there is limited review have been done to compile and review the physiological method, driving distraction and its effect on the driver. Therefore, this paper aims to review the effect of driver’s in-vehicle distraction and secondary task during driving on driver’s health and safety. A systematic search was conducted on the basis of the preferred reporting items for systematic reviews by using PRISMA guidelines. Any criteria were imposed for the included sample. The search was focused on in-vehicle secondary task and distraction. Results showed that 21 articles investigated the major ability for in-vehicle secondary task distraction using physiological measures. Findings showed a significant effect of the in-vehicle secondary task and distraction on driver’s condition. Drivers’ characteristics such as their experience and age are also factors in determining the effect of distraction and secondary tasks on their condition. However, further studies are needed to understand the physiological effect of secondary task on young driver’s condition due to the relatively higher number of crash rates from those at a young age.

Keywords: Disturbance; vehicle; road; environment; workload; physiology

A proton-exchange membrane (PEM) is a vital component in fuel cells as a solid electrolyte that conducts ions. The high cost and degradation of Nafion® membrane in low-temperature fuel cells limits the technology’s commercialization. The development of intermediate (IT-PEMFCs) to high-temperature (HT-PEMFCs) fuel cells operating within the range of 80–200 °C has made progress over the last few decades, and improvements in water management addressing the issues of low-temperature PEMFCs have been observed. However, these types of PEM fuel cells (IT-PEMFCs and HT-PEMFCs) still face considerable challenges, such as unsatisfactory performance stability at high temperatures. Particularly, in HT-PEMFC, despite the high acid doping level (ADL) in membranes as a potential means to improve proton conductivity, high ADL decreases the membrane’s mechanical stability. Recently, metal–organic frameworks (MOFs) have achieved satisfactory results in applications of PEM modification. This manuscript reviews the development in applying MOFs in improving the properties of composite membranes in IT- and HT-PEMFCs by using SPEEK and PBI, respectively. The synthesis strategies using MOFs in the PEM are discussed together with the electrochemical properties obtained. The success of incorporating of MOFs into PEMs could shed light on the synthesis of new-generation IT- and HT-PEMFCs, which could improve several properties such as mechanical and thermal stability, oxidative stability, and acid-retention capacity.

Keywords: Metal-organic frameworks; proton exchange membrane; fuel cell

Proton-conducting ceramics based on perovskite-type oxides have been significantly applied in a wide range of electrochemical devices such as fuel cells, hydrogen sensors, and steam electrolysers. One of the emerging applications of these ceramic proton conductors is as an electrolyte component in a solid oxide fuel cell (SOFC), where the proton is mobilized from the anode to the cathode side via these conductors. The proton (hydrogen ion) diffusion mechanisms and activation energies (Ea) in these materials are heavily influenced by their composition, stoichiometry, and crystal structure. Hence, this review presents and discusses the mechanism of hydrogen ion movement for proton-conducting solid oxide fuel cells or known as proton ceramic fuel cells (PCFCs), based on experimental and modelling data, including the vehicular and the Grotthuss mechanisms. This review will provide a brief understanding of the connection between experimental and modelling evidence for proton mechanisms in perovskite electrolyte materials.

Keywords: Proton transport; perovskite oxide; proton-conducting ceramic; DFT

The solid oxide fuel cell (SOFC) is a promising technology with specific characteristics for generating electricity by using hydrogen and oxidant as fuel. Typically, SOFC’s use Samarium doped Ceria (SDC) as an electrolyte material as the ionic conductivity of SDC was better at lower operating temperatures which are below than 700°C that making it a good option for low and moderate temperature applications for SOFC. However, SDC electrolytes are cannot be densified below 1500°C. If a densified ceria-based electrolyte can be prepared at lower temperatures it can be co-sintered with another electrode component. This simplifies the fabrication process and reduces the cost. Other than that, it can help with porous electrode microstructure control and avoiding phase diffusion and chemical interaction problems. As a result, decreasing the sintering temperature may be another step toward commercialising SOFC technology. The modification of electrolyte by adding sintering aid was found as an effective method to lowering the sintering temperature. This paper, therefore, focuses on reviewing the attempts made to modify SDC electrolyte by adding sintering aid (Li2O, CoO, CuO and FeO) in order to lowering sintering temperature. The studies related to temperature reduction, relative density, the microstructure of grains and conductivity of electrolyte was critically reviewed.

Keywords: SOFC; SDC; sintering temperature; sintering aid; electrolyte

Burning of post-harvest non-edible agro residues (biomass) are the major source of environmental and soil pollution, affecting the lives of millions of people, especially in certain demography of developing countries like India. Non edible agro residues contain toxic structural constituents, making it unsuitable for cattle feed. However, due to its cellulosic and lignocellulosic constituents, it has the potential to be used as a promising feedstock to develop value added energy products. Authors in this review paper have comprehensively reviewed the technological aspects related to conversion of agro residues into value added energy products like bio-oil, bio-char, and pyro gas. Various non-edible agro residues like Cotton stalk, castor stalk, Maize stalk, Rice straw, Rice husk, Corn cob, Sugarcane bagasse, and wheat straw etc., have been reviewed for its potential as feedstock material for thermo chemical conversion to obtain energy products like bio-oil, bio-char, and pyro-gas. Different physio-chemical properties, its chemical characterization methods, different bio-oil upgradation techniques, Techno-economic analysis (TEA), and Life Cycle Assessment (LCA) have been reviewed for different thermo-chemical conversion processes. The reviewed works reveal that byproducts derived from pyrolysis of non-edible agro residues have potential to be used as biofuels. Bio-oils after upgradation may be used as fuel, bio-char with appropriate pulversing may be used as soil nutrient, and pyro-gas may be used as energy gas or carrier gas for process industries. LCA of different processes for different agro residue-based biofuels indicate that conversion of biomass into energy fuels is an sustainable, and economical solution for the environment point of view and economic point of view through pyrolysis process as compare to the other conversion processes because pyrolysis process can accommodate agro waste and produce bio-char and pyro-gas along with bio-oil having capacity to generate good revenue.

Keywords : Biomass; pyrolysis; bio-oil upgradation; sustainable biofuels; life cycle assessment

High data rate transfers, high-definition streaming, high-speed internet, and the expanding of the infrastructure such as the ultra-broadband communication systems in wireless communication have become a demand to be considered in improving quality of service and increase the capacity supporting gigabytes bitrate. Massive Multiple-Input Multiple-Output (MIMO) systems technology is evolving from MIMO systems and becoming a high demand for fifth-generation (5G) communication systems and keep expanding further. In the near future, massive MIMO systems could be the main wireless systems of communications technology and can be considered as a key technology to the system in daily lives. The arrangement of the huge number of antenna elements at the base station (BS) for uplink and downlink to support the MIMO systems in increasing its capacity is called a Massive MIMO system, which refers to the vast provisioning of antenna elements at base stations over the number of the single antenna of user equipment. Massive MIMO depends on spatial multiplexing and diversity gain in serving users with simple processing signal of uplink and downlink at the BS. There are challenges in massive MIMO system even though it contains numerous number of antennas, such as channel estimation need to be accurate, precoding at the BS, and signal detection which is related to the first two items. On the other hand, in supporting wideband cellular communication systems and enabling low latency communications and multi-gigabit data rates, the Millimeter-wave (mmWave) technology has been utilized. Also, it is widely influenced the potential of the fifth-generation (5G) New Radio (NR) standard. This study was specifically review and compare on a few designs and methodologies on massive MIMO antenna communication systems. There are three limitations of those antennas were identified to be used for future improvement and to be proposed in designing the massive MIMO antenna systems. A few suggestions to improve the weaknesses and to overcome the challenges have been proposed for future considerations.

Keywords: Massive MIMO; Fifth Generation;5G; Millimetre-wave; mm-wave; antenna design

The increasing consumption of fossil fuels and the high emission of exhaust gases have encouraged researchers to explore different approaches to reduce its consequences. Apart from focussing on the engine components, modifications on the fuel molecules can also deliver huge improvement. Using magnetic fields on the fuel line becomes one of the promising alternatives to give a better performance of the engine and produce less hazardous emissions. Previous researchers have proven that the magnetic field could enhance combustion rate by influencing the fuel molecules. After the magnetic treatment, hydrogen atoms in the hydrocarbon fuel tend to react better with oxygen molecules, thus creating more improved combustion. However, the results were varied among the researchers with huge ranges, especially in the rate of fuel-saving and emissions depending on the experiment’s setup. While many previous researchers have reported significant improvement in engine performance with the use of the magnetic fields on the fuel line, some reported insignificant effects. Despite the promising potential, this method has not received much attention from both automotive manufacturers and users. The objective of this paper is to discuss the previous studies regarding influences of the magnetic field to the hydrocarbon fuel and engine’s output. Based on the up-to-date research findings, discussion and explanations consisting of molecular reactions, important factors in influencing the changes in the engine performance and exhaust emissions are to be discussed.

Keywords: Engine; performance; fuel consumption; emission; magnet

Nowadays, leachate production is a big concern and causes a serious hazard to the soil and groundwater which causes the subsurface soil to be polluted as a result of the loss of soil quality and environmental pollution. This study aims to study the potential of using kenaf core fiber and marine clay mixtures as improved landfill liner material. Relevant laboratory tests such as atterberg limit test, specific gravity test, and particle size distribution were performed to examine basic geotechnical properties of marine clay soil collected from Batu Kawan, Penang. Besides that, compaction test and hydraulic conductivity test were carried out for soil mixed with kenaf core fiber to determine the strength and permeability characteristics. The results found that the marine clay has significantly adequate physical properties to be used as a landfill liner. The permeability test for marine clay soil inclusion of kenaf core fibre indicated that the hydraulic conductivity of the samples admixture for 0%, 4%, 8%, and 12% ranged between 6.68 × 10-9 and 1.57 × 10-8 m/s. Compaction of marine clay mix kenaf core fibre samples resulted in maximum dry density, ρdmax that ranged between 0.936 and 1.595 g/cm3 and optimum moisture content, wopt that ranged between 19.8% and 24%. Hence the inclusion of kenaf core fiber in marine clay soil improves the maximum dry density value, decrease permeability of marine clay and could be potentially used for landfill liner material.

Keywords: landfill liner, marine clay soil, kenaf core fiber, compaction, hydraulic conductivity

In this revolutionized era, electricity has become an essential necessity of humans. People all over the world are concerned about the effects of HVTL (high voltage transmission lines) and their severe effects impacting on their health. Over the last two decades, developed countries have become increasingly concerned about an increase in electromagnetic fields, which poses health risks. The electromagnetic field emitted by HVTL will cause a low current to pass through the bodies. The electricity system produces low frequency electromagnetic field, which lead to the health hazards. The critical problem to those who are living near HVTL, therefore our fundamental task is to let them aware of the risk. Due to harmful exposures of electric and magnetic field, farmers working under HVTL or having their residences, suffering through severe effects in the form of different diseases. The main aim behind this research is to design GUI based software having two parts which helps to bring output of the electromagnetic field exposures with the help of various parameters includes different weather conditions affecting electric field, how people of different ages are being affected through it, identification of the regions need further protection by developing a proper mathematical model. Two approaches were used, one is to interface GUI with different sensors and second is user define function. On the basis of output EMF it will be able to find out the possible disease by using the data of WHO, ICNIRP and the data which is collected from surveys of different regions.

Keywords: Electromagnetic Radiations; High Voltage Transmission Lines; IIOT; Diseases; International Commission on Non-Ionizing Radiation Protection (ICNIRP); International Radiations Protection Association (IRPA)

Recently, there has been a growing tendency of interest from researchers to use ambient energy to power electronic equipment using various energy harvesting techniques. Micro energy harvesting is a potential technique to convert ambient energy from the environment to electrical energy. The wireless sensor network requires a constant source of electrical energy to activate it and the radio frequency (RF) ambient energy source that always exists in the environment is very suitable for use. Therefore, the designed and developed RF micro energy harvester consisting of an impedance matching circuit, a voltage multiplier and a rectifier circuit does not require an external energy source to activate it. This RF micro energy harvester circuit is constructed and simulated using PSPICE software by connecting a 1 MΩ load resistor. At an input power of -20 dBm or 10 μW captured by the MEMS antenna, the values of the output voltage and current produced in this energy harvester circuit are 2.36 V and 1.7 mA, respectively. Meanwhile, the maximum efficiency percentage of the entire RF micro energy harvester circuit is 55.7%. The output power value of 40.12 mW is higher than the input power value of 10 μW. This RF micro energy harvester is capable of activating a wireless sensor network with a minimum input current requirement of 1 mA. An integrated circuit layout using 180 nm CMOS technology for a multiplier circuit has been successfully developed with a very small size of 22.48 x 56.96 μm2 as proof that the circuit can be fabricated as an integrated circuit chip.

Keywords: Micro energy harvester; RF; low power; performance

In industries, the shoulder fillet round bar (step shaft) is used to transmit the power and motion to fulfil the requirements of a specific application. A step is provided on the shaft for mounting bearings, sprockets, flywheels, pulleys etc. A step on the round bar behaves as discontinuity. The local stresses developed in the vicinity of the discontinuity, known as stress concentration (SC). The SC is one of the major factors responsible for failure of the mechanical component having discontinuity like step shaft. The shoulder fillet is provided in a step to reduce stress concentration on the shaft. The stress concentration can be measured using the stress concentration factor (SCF). The SCF can be calculated with the help of a fringe pattern. In the present research, experimentally, the fringe pattern was not obtained on the shoulder fillet round bar due to the curved surface of the bar. To overcome this problem, a partial slicing model approach was used. Even though, the obtained fringe patterns were not clear due to the sharp corners present in the partial slicing models. The SCF can be calculated with the help of a fringe pattern. These limitations can be overcome using Finite Element Analysis (FEA) and full slicing approaches. In the present research, the FEA was performed on the flat and curved plate (slice). The Rapport factor (RF) was derived for all possible D/d ratios and determined the effect of a curved surface by finding the equivalent SCF of the shoulder fillet round bar. The FEA results of SCF were validated using the Peterson graph and considered acceptable as per the prevalent industry practices. The present study may help the design engineer to find the minimum SCF for the design of the shoulder fillet round bar for the concerned application. It will reduce the design iterations and chances of failure of the shoulder fillet round bar during its operation.

Keywords: Stress concentration (SC); Stress concentration factor (SCF); Finite Element of Analysis (FEA); Rapport factor (RF); discontinuities; shoulder fillet; flat plate; curve plate

High demand for halal products globally has contributed the rapid development of halal small and medium enterprises (SMEs). Halal Manufacturing Supply Chain Management (HSCM) has been adopted by SME as a dynamic action in improving firm performance (FP). However, the benefit of HSCM can not be fully achieved without effective strategic manufacturing management (SMM). Based on this concept, the relationships between SMM, HSCM, and FP have been debated. Hence, rigorous research is necessary to identify the factors and the implications of SMM towards HSCM and also FP as a whole. The primary objective of this research is to recognize the SMM practises applied in the halal manufacturing SME sectors. This research uses purposive sampling. A Structural Equation Modeling (SEM) by Partial Least Square (PLS) technique has been employed in analysing the collected data. Market orientations were found to have a significant impact on business performance when applied to halal-certified SMEs. On the other hand, despite having statistically significant effects on business performance, supply chain orientation exerted a reduced influence. This study establishes a framework for halal practitioners to improve their business operations through the application of strategic orientation principles.

Keywords: Supply chain orientation; market orientation; halal industry, firm performance

Ultrasonic horn (USH) is a key component in high intensity power ultrasonic systems to enhance vibration amplitude at tool end (VATE). Due to high intensity ultrasonic operating frequency of at least , horn may be exposed to high stress levels leading to failure. The primary objective of USH design is to achieve high vibration amplification with good strength. In present research, the effect of fillet radius / roundness on ultrasonic composite horn (USCH) performance was investigated for various materials: stainless steel, aluminum, titanium, and steel, respectively, using finite element analysis (FEA). USCH was developed for ultrasonic machining of soft and brittle composites, especially Nomex honeycomb composite. The important performance parameters considered were longitudinal modal frequency (LMF), Von Mises (VM) stresses, magnification factor (MF), VATE and factor of safety (FS). LMF was found to increase, with decrease in VATE and VM stresses by increasing the roundness at the transition section. Titanium was observed to be highly appropriate material for USCH, because it delivered at least 81.6 % to 142.62 % more vibration amplification and up to 4 times higher factor of safety, consequently, operating life in comparison to other USCH materials.

Keywords: finite element analysis (FEA); roundness; stresses; ultrasonic composite horn (USCH); vibration amplitude at tool end (VATE).

The foundries are facing problem-related to the selection of the parameter’s value for minimum rejection and maximum productivity. The furan no-bake binders system guaranteed dimensional stability and a comparative good surface finish of the casting. Based on past data in the industry, it is found that gas porosity defect is one of the highest. The phenomenon of the formation of the bubble in the fissures of the mould-metal interface, and later on trapping during the solidification leads to gas porosity. The current research work is focused on the minimization of the defect by the selection of the optimum range of input variables. Based on rigorous literature survey and industrial expert’s opinion, it is found that the parameters like grain fineness number (GFN) of the sand, loss on ignition (LoI) of the used sand, the sand temperature at the mixing time, potential of hydrogen (pH) are important parameters for gas porosity defect in the casting.Design-Expert software and particularly response surface methodology (RSM) and sequential approach using the face-centered central composite design is used for the experiments. The results show that a quadratic model with the removal of some insignificant term is a comparatively best fit for gas porosity defects. After analysis, various favorable levels of different parameters are obtained. The research work is based on realistic problems of the foundries and based on the experimental work. Thus, the provided solution is very much useful for foundries to reduce the rejection, particularly for furan no-bake with furfuryl alcohol as resin and sulphonic acid as catalyst. The research problem addressed in the paper is a genuine problem of the foundries and the sole work is based on experimental evidence.

Keywords: Furan no-bake; Loss on ignition; pH; Response surface methodology

In this study, the ability of numerous statistical and machine learning models to impute water quality data was investigated at three monitoring stations along the Langat River in Malaysia. Inconsistencies in the percentage of missing data between monitoring stations (varying from 20 percent (moderate) to over 50 percent (high)) represent the greatest obstacle of the study. The main objective was to select the best method for imputation and compare whether there are differences between the methods used by the different stations. The paper focuses on different imputation methods such as Multiple Predictive Mean Matching (PMM), Multiple Random Forest Imputation (RF), Multiple Bayesian Linear Regression Imputation (BLR), Multiple Linear Regression (non-Bayesian) Imputation (LRNB), Multiple Classification and Regression Tree (CART), k-nearest neighbours (kNN) and Bootstrap-based Expectation Maximisation (EMB). Remarkably, among all seven imputation techniques, the kNN produces identically reliable results. The imputed data is all rated as ‘very good’ (NSE > 0.75). This was confirmed by the calculation of |PBIAS|<5.30 (all imputed data are‘very good’) and KGE≥0.87 (all imputations are rated as’ good’). Imputation performance improves for all three monitoring stations with an index of agreement, WI ≥ 0.94, despite varying percentages of missing data. According to the findings, the kNN imputation approach outperforms the others and should be prioritised in actual use. Future research with the existing methods could benefit from the addition of geographical data.

Keywords: Imputation methods; missing data; multiple imputation; evaluation criteria; water quality

Metal-organic frameworks (MOFs), are known as novel types of crystalline materials formed by organic bridging ligands and coordination of metal ions. MOFs have unique characteristics such as high porosity, large surface area, and high structural durability. However, MOFs have some disadvantages such as having low stability, as well as electrical conductivity which causes their catalysis efficiency and application to be limited to a large extent. Thus, among the solutions made in previous studies, to overcome the disadvantages of this MOF is to combine it with carbon-based material to form a composite with better properties than pure MOF. This current review focuses on the performance of carbon-based material/MOF catalyst composites for direct borohydride fuel cell (DBFC) application. The catalytic oxidation of borohydride performance using carbon-based material/MOF catalyst is clearly and scientifically observed to enhance the catalytic activity in previous studies. There is no denying that carbon-based materials are widely used in fuel cell applications and have great advantages such as low toxicity, unique structure, good porosity properties, lightweight, controllable heteroatom doping, and easy processing, as well as excellent mechanical, chemical, and thermal properties. Thus, this review provides a summary of the application of carbon-based materials and MOFs with the properties and performance of this composite including the catalytic oxidation activity and DBFC potential for the entire system.

Keywords: Metal-organic frameworks; carbon, and graphene-based materials; direct borohydride fuel cell

Various materials have been produced to be used as feeder material in 3D printing application to obtain the level of mechanical properties and physical properties of a product. Before to its usage as a 3D printing feed material, polyamide-reinforced carbon fibre composites were investigated for flowability and diffusion behaviour. Using a heated nozzle to transform polymer filament into a semi-liquid that is extruded to create a structure layer-by-layer, the primary issue to prevent is delamination. For the success of this study, there are 2 main methods, namely to study the physical properties of carbon fibre reinforced polyamide composites against the composition of 20 wt.% carbon fibre and to study the temperature and rheological load on the rheological properties. Rheological test analysis found that the material flowability of 20 wt.% CF/PA at temperature parameters 210 °C, 230 °C and 250 °C against rheological loads (40, 60, 80) N recorded a range of viscosity values between 48.80 Pa.s to 97.88 Pa.s and shear rate value range between 19700 s^-1 to 20270 s^-1. Parameter optimization analysis using Taguchi method found that the largest factor contributing to the viscosity of CF/PA composite feed material was the addition of load applied. Moreover, the microstructural results of CF/PA composites show that smoother surfaces and good polymer structural bonding occur at an extrusion temperature of 250 °C. As a result, the rheology-derived flow rate may be used to tackle the problem of delamination and layer separation in 3D printing.

Keywords: Carbon fiber; polyamide; viscosity; shear rate; temperature; load

The proton exchange membrane fuel cell (PEMFC) system was an electrochemical device that generates electricity through the reaction of hydrogen and oxygen without combustion. Proton Exchange Membrane (PEM) stacks typically consisted of components combined into one unit and equipped with suitable clamping torque. This was to prevent reactant gas leakage and minimize the contact resistance between the gas diffusion medium and the bipolar plate. The combined components consisted of a bipolar plate with a flow field, current collector, membrane electrode assembly (MEA), endplate, and gasket. PEMFC performance was measured concerning its power output, which depends on temperature and the operating pressure. Various efforts had been made to determine the optimal compaction pressure and its distribution through simulations and experiments. Therefore, this research analyzed the static stress of membrane electrode assembly (MEA) and gasket in PEMFC stack assembly pressure. The components’ geometric dimensions and mechanical properties, such as endplates, current collectors, bipolar plates, MEAs, and gaskets, were combined for electricity. Pressure-sensitive film (Fuji measure film prescale) was also used to visualize contact pressure distribution between the MEA and the bipolar plate. The result showed that the color variation of the pressure film indicates the exact distribution of pressure entering the stacking design and the contact image. In conclusion, the detailed contact pressure distribution was an important influence on heat transfer processes and local electrochemical reactions in cell stacks.

Keywords: Proton exchange membrane fuel cell; stack assembly; pressure distribution; pressure sensitive film

Three-dimensional (3D) structures made of graphene sheets have been developed recently, and have resulted in the development of a new class of graphene materials known as 3D graphene materials. High-quality free-standing 3D graphene foam has been synthesized by chemical vapor deposition (CVD) on nickel foam followed by a chemical etching process to remove the nickel foam as a template. Field-emission scanning electron microscopy (FESEM), x-ray diffraction (XRD), and Raman spectroscopy measurements were performed to investigate the morphologies, crystal phase, and the structure of nickel foam (NF), graphene/nickel foam (Gr/NF), and 3D graphene (3D Gr). In this study, the influence of etching solution and etching time on Gr/NF to produce free-standing 3D Gr was investigated. XRD spectroscopy showed that the mixed solutions of 1M FeCl₃:1M HCl at 80 °C for 3 h can significantly remove the NF and no peaks of NF are observed, thus indicating a high crystal quality of 3D Gr was obtained. In addition, XRD spectroscopy revealed that by increasing the etching time beyond 3 h, the intensity of diffraction peaks decreases, thus degrading graphene quality. This research emphasizes the significance of proper selections of etching solution and etching time in removing the NF to maintain the characteristic, quality, and surface morphology of 3D Gr after the etching process.

Keywords: 3D graphene; chemical vapor deposition; etching solution; etching time

South Atlantic Anomaly (SAA) region is describe as a region with weak Earth magnetic field. The method apply is power spectrum analysis. By applying the power spectrum analysis method, the value of spectral exponent, β is obtained. From the spectral exponent, β, the Hurst exponent can be determined. The research is conducted by studying the SAA region where comparisons is made between the middle latitude region and high latitude region. 2 active period has been research, 11 March 2011 and 29 May 2011 and 2 normal period has been studied, 9 March 2011 and 12 May 2011. The research conduct indicate the SAA region tend to be persistent and as the vertical field intensity and total field intensity increase, the region tend to have a mixture of antipersistent and persistent characteristic. The high latitude region in this research conduct indicate a tendency to be antipersistent. By conducting research on the SAA region, it can provide knowledge of the dynamics and conditions of our Earth. The SAA region is a region where it is exposed to energetic particles. Satellites passing through the SAA region are also vulnerable to danger. Therefore, the region conducted on the SAA region, can provide knowledge on the characteristics of the SAA region. Research on SAA may increase knowledge of the Earth’s magnetic field.

Keywords: South Atlantic Anomaly, vertical field intensity, total field intensity

Road safety and pavement condition are considered top priorities in our civilized societies, and it’s important that the pavement condition remains in an excellent state for a long time. However, eventually, the pavement will get exposed to different types of distresses as a result of traffic loads, rough environment conditions, soil conditions, and underline subgrade. Therefore, to achieve the required standards for the pavement surface roads in our country and provide the best performance: detection and measurements of distresses extension must be included in maintenance preparation. This paper proposes a technique for crack detection based on digital image processing using a programming language called Matrix Laboratory known as MATLAB. The main target is to estimate the pavement’s length, width, and area by capturing the image using a digital camera with the required precautions and image implementation. Secondly, developing an image pre-processing operation to eliminate environmental interference as much as possible and subsequently use the image thresholding method to separate the pixels within the image into two groups to find the thresholding value for image binarization. The method successfully detects and removes the presence of unwanted objects in an image, even in difficult situations where surfaces are less visible. Verification showed good results with an excellent processing time, which can be considered an indicator of pavement crack parameters.

Keywords: Digital image processing; Pavement evaluation; Crack detection; Parameters estimation

Solar activity such as solar flares causes increased X-ray and ultraviolet ray flux. This event will cause sudden ionospheric disturbances (SID) and disrupts the communication systems as well as the space-based equipment on Earth. Public awareness especially to school students on the effects of solar activities towards humans on Earth is very important as the dependency of human daily life on space technology is increasing. The awareness has been conducted by the Space Science Center, Institute of Climate Change, UKM using UKM-SID™ system. Based on the program, it was found that school student experienced constraints in the process of analyzing data due to the absence of computers in schools. Therefore, UKM-SID™ system, with portable kit equipped with an interactive software to produce an easy-to-understand figure, was proposed. An algorithm was also developed to transfer the observed data onto the server in near real time. The developed Graphical Interface software showed a visualized sunrise and sunset patterns which is in agreement with the previous study. A solar flare was detected on 1 December 2020. The observed data is also successfully uploaded onto the server in near real time. Result shows that this new UKM-SID™ system is able to capture the solar flare occurrence. This new system is also at an optimal and sophisticated level compared to the technology that has been used. Hence, the researchers believe the UKM-SID™ is able to help educators, students and the general public in the learning of space science more effectively.

Keywords: Solar flare; UKM-SID™; GUI; Python; Very Low Frequency (VLF)