International Journal of Engineering Materials and Manufacture

Published by Deer Hill Publications
Online ISSN: 0128-1852
Publications
Dear IJEMM Members I wanted to provide an update to the broader community of International Journal of Engineering Materials and Manufacture (IJEMM) regarding our efforts to alleviate the spread of the COVID-19 coronavirus. The Editorial Board is deeply sympathised with the people suffering worldwide due the outbreak of pandemic COVID-19. We are closely monitoring the outbreak and implementing social isolation and other measures, according to World Health Organisation guidelines, to mitigate the impact on our members, volunteers and customers around the world. As the safety of people is of highest priority, our aim is to continue delivering our services for editors, reviewers, authors, readers, and other members to the highest possible standards using our online web-based platforms. I trust that each of you is doing well and finding ways to cope with this challenging pandemic situation which is a test from God, the almighty. Please stay safe, do not panic, heighten your spirituality and seek forgiveness. With thanks and regards, Professor Ir. Dr. Mohammad Yeakub AliEditor-In-ChiefInternational Journal of Engineering Materials and Manufacture
 
Recently, there is quest for the use of inexpensive, non-toxic, non-biodegradable, readily available and environmentally acceptable corrosion inhibitor. Studies have shown that these properties could be achieved through the use of plants as inhibitor. Inhibiting effect of Prosopis Africana (Iron Tree) seed extracts were assessed on a sample of low carbon steel in 1M HCl with varying proportion of the seed extract using gravimetric, Tafel polarization and gasometrical measurement techniques. The results show that weight loss/corrosion rate decreases with increase in the extracts’ concentrations. Good inhibiting efficiency of Prosopis Africana extracts with optimum inhibiting efficiency of 97.7% at 1.0 g/l after 120 hours exposure in gravimetric measurement was attained. TAFEL polarization results revealed that the Prosopis Africana extract shows that the corrosion current density decreases with the increase in the concentration of the extract. The extract is found suitable as green inhibitor for corrosion of low carbon steel in the studied medium.
 
Cutting fluids play a major role in machine operations, life of tools, workpiece quality and overall high productivity which are considered as potential input for minimal tool wear, minimal surface roughness and better machining finished product owing to the ability to prevent overheating of the workpiece and cutting tool. In this paper, the challenge of environmental biodegradability, tool wear and workpiece surface roughness prompt the need to evaluate and compare the performance of Jatropha oil based cutting fluid (JBCF) with mineral oil based cutting fluid (MBCF) during turning with AISI 304 Alloy steel which are presented. Test were conducted on the Physiochemical property, fatty acid composition (FAC), cutting fluids formulation of oil ratio to water ratio in proportion of 1:9, turning operation and response surface methodology (RSM) design of experiment were carried out and used respectively. Results from FAC indicated that jatropha seed oil (JSO) has an approximately 21.6% saturated fat with the main contributors being 14.2% palmitic acid. The physiochemical property results show pH value 8.36, Viscosity 0.52 mm2/s, resistant to corrosion, good stability and a milky colouration. The S/N ratio for main effect plot for JBCF and MBCF stand at 1250 CS, 1.15 FR and 0.65 DOC; and 500 CS, 1.15 FR and 0.65 respectively with R-sq = 85.14% and R-sq(adj) = 71.76% for JBCF Ra and R-sq = 71.24% and R-sq(adj) = 56.35% for JBCF Tw, compared to R-sq = 84.44% R-sq(adj) = 70.43% is for MBCF Ra, and R-sq = 70.48% and R-sq(adj) = 55.92% for MBCF Tw. Conclusively, JBCF exhibit minimal surface roughness, minimal tool wear, minimal environmental biodegradability and overall better performance compare to MBCF which makes it more suitable for turning of AISI 304 Alloy steel and is in good agreement with previous work.
 
Present work describes the failure investigation of blade lock ring of 4th stage compressor rotor. The lock ring is fabricated from martensitic stainless steel. The microstructure of failed lock ring is tempered martensite. It shows non-metallic inclusions with three distinct shapes namely, elongated (MnS), globular (Al2O3) and complex shaped (oxy-sulphide). The corrosion pits and corrosion debris are observed in un-etched microstructure and fracture surface, respectively. The tree like branching cracks has observed at several places near surface. These cracks have initiated from the corrosion pits and then propagated inside the material. The interface of inclusions and matrix has also acted as crack initiator. The lock ring has initially suffered pitting corrosion in service and then cracks have propagated inside the material by stress corrosion cracking.
 
The quality of machined parts and the productivity of machining that leads to economic sustainability. These factors are also vital for machinability improvement for materials, as well as, for economically sustainable manufacturing. Due to their poor machinability titanium alloys (Ti-alloys) are categorised as difficult-to-machine materials. For the same reason products made of Ti-alloys are highly expensive and are used only in strategic and sophisticated industries. A series of real-life experimental investigations was carried out to reveal the economic optimal zones of machining parameters that can produce the best possible surface roughness in machining Ti-6Al-4V alloy, using the coated carbide cutting tools, in shortest period of operation time. As the output of the research, for using the coated carbide tools for machining the investigated Ti-alloy, optimal zones of cutting speed, feed rate and depth of cut have been proposed and presented in graphical format. The current research revealed that all three groups (with nose radius Nr = 0.4, 0.8, and 1.2 mm) of coated carbide tools are capable to produce best surface finish, ranging between Ra = 0.5 - 1.0 µm, with cutting speed starting at V = 60 m/min and beyond at least up to V = 250 m/min while keeping the feed rate and depth of cut as constants as f = 0.1 mm/rev and d = 0.5 mm. The data on the graphs may help researchers, engineers and manufacturers to select optimal economic cutting speed, feed rate and depth of cut to achieve a certain level of surface roughness of machined components as assigned by the product designer on the part drawing. This reduces the production cost substantially, reduces number of defect products and improves product quality for machined parts.
 
By virtue of high-strength verses weight ratio aluminium alloys are achieving attentions in automobile, marine, and aircraft industries as it reduces the fuel consumption for running the vehicles. But their main drawback is the destruction of their carefully engineered microstructures by high heat generated in traditional welding processes. Friction Stir Welding (FSW) minimizes excessive heat in the welding zone and does not influence the microstructural features. FSW is currently one of the recommended solutions for manufacturing aluminium alloy welded machine parts. In this study, AA6061 Al-alloy strips were lap joined using the improvised FSW setup tool clamping it on the spindle of a CNC milling machine with the speed rate varied from 1000 rpm to 3000 rpm, and three different feed rates 5, 15, and 25 mm/min. Shear strength experiments of these joints revealed that samples created with the speed rate of 1000 rpm and feed rate of 25 mm/min performed best showing the highest load carrying capacity of 8976 N with elongation of 1.04%. They also demonstrated highest Vickers hardness value of 31 at the centre of the weldment.
 
Cooling rate curve of cast specimen (a) cooled in mould at room temperature (b) cooled in mould immersed in ice block (c) cooled in mould at 140 °C (d) cooled in mould at 230 °C.
Plate 1: Microstructure of the 6xxx aluminium alloy under different cooling rates (a) mould was cooled at room temperature (b) mould was cooled in ice block (c) mould was cooled mould temperature 430 o C (d) mould was cooled at 230 o C.
Corrosion data of 6xxx aluminium alloy under different cooling conditions.
The applicability of materials is highly dependent on its microstructure and mechanical properties. Aluminium alloy is being used extensively under diverse conditions. This study investigates the effects of cooling rate on the microstructure, mechanical properties and corrosion resistance of 6xxx-series aluminium alloy. Aluminium ingot was melted in a muffle furnace and cast into rods. The cooling rate was controlled by holding the moulds at different temperatures. Microstructural characteristics were examined by optical microscopy. Mechanical properties such as impact strength, hardness, and tensile strength were analysed using standard methods. Corrosion resistance was evaluated by potentiodynamic polarization. It was found that microstructures are dominated by ferrite and pearlite phases with different morphologies and grain sizes depending on the cooling rate. Increasing the cooling rate resulted in microstructural refinement and chemical homogeneity, improvement in mechanical properties and corrosion resistance of the 6xxx alloy.
 
Electro-chemical polishing (ECP) was utilized to produce sub-micron surface finish on Inconel 718 parts manufactured by Laser Powder-Bed-Fusion (L-PBF) and extrusion methods. The L-PBF parts had very rough surfaces due to semi-welded powder particles, surface defects, and difference layer steps that were generally not found on surfaces of extruded and machined components. This study compared the results of electro-polishing of these differently manufactured parts under the same conditions. Titanium electrode was used with an acid-based electrolyte to polish both the specimens at different combinations of pulsed current density, duty cycle, and polishing time. Digital 3D optical profiler was used to assess the surface finish, while optical and scanning electron microscopy was utilized to observe the microstructure of polished specimens. At optimal condition, the ECP successfully reduced the surface of L-PBF part from 17 µm to 0.25 µm; further polishing did not improve the surface finish due to different removal rates of micro-leveled pores, cracks, nonconductive phases, and carbide particles in 3D-printed Inconel 718. The microstructure of extruded materials was uniform and free of processing defects, therefore can be polished consistently to 0.20 µm. Over-polishing of extruded material could improve its surface finish, but not for the L-PBF material due to defects and the surrounding micro-strain.
 
Additive Manufacturing (AM) of metallic components shows unfavorable properties in their as-built state; surface roughness, anisotropy, residual stresses, and internal /surface defects are common issues that affect dynamic properties of AM metals. This paper reviews traditional fatigue testing techniques, summarizes published fatigue data for wrought and additively manufactured metals with focus on Inconel 718. Surface and volume defects of AM metals were presented and how post processing techniques could improve fatigue performance were shown. Different methods for normalizing fatigue data were explored due to varying results of different fatigue testing techniques.
 
This study explores the application of Electron-Beam Welding (EBW) for joining Laser Powder-Bed-Fused Inconel 718 (L-PBF IN718) superalloy. Three different levels of electron beam speed and beam current were explored to give nine different electron beam heat inputs for experimentation. To define the weld characteristics microhardness, tensile, and fractography analysis using scanning electron microscopy, optical microscopy, and energy dispersive spectroscopy were conducted. Typical nail-shaped weld geometry was observed with penetration depth proportional to heat input. Most welded samples exceeded the yield strength (600MPa) and tensile strength (920MPa) requirements from the ASTM F3055 specifications for additively manufactured IN718, however, the specimens did not meet the ductility requirements (27%). Brittleness of the weld was attributed to the presence of brittle secondary phases in the weld matrix, and unfused metal powder of adjacent L-PBF layers. Post-processing heat treatments were recommended to improve the weld quality while improving the ductility of EBW joints.
 
Abrasive water jet (AWJ) is one of the most advanced and valuable non-traditional machining processes because of its massive advantages of removing metals ranging from hard to soft. This paper focused on studying the influence of jet pressure, feed rate and standoff distance on surface roughness during cutting carbon steel using abrasive water jet cutting. A surface roughness device assessed the surface roughness by performing sixteen experiments to identify the distinct texture of the surface. Based on the experiences, the best surface roughness value was 3.14 μm at jet pressure 300 MPa, standoff distance 4mm and feed rate 30 mm/min. The Taguchi method was introduced to implement the experiments and indicate the most influential process parameters on average surface roughness. The experimental results reveal that feed rate has a significant effect on average surface roughness.
 
The weak ferromagnetic property and the electromagnetic waves absorption characteristic of La(1-x)BaxMnO3 (LBMO) compounds have been investigated. The samples of LBMO that are LaMnO3 (S0), La0.9Ba0.1MnO3 (S1); La0.8Ba0.2MnO3 (S2); and La0.7Ba0.3MnO3 (S3) were synthesized using high energy milling (HEM) method. Samples were characterized by means of XRD (X-ray diffractometer), HRPD (high-resolution powder neutron diffractometer), EDS (energy dispersive X-ray spectroscopy, VSM (vibrating sample magnetometer), and VNA (vector network analyzer). There is no magnetic ordering of ferromagnetic in S1 and S2 samples due to the Ba occupation factors of both less than 0.2. The Ba content in the S3 sample is greater than 0.2, hence the ferromagnetic property of the compound is not so visible with the VSM as well as the VNA. The absorption characteristics of electromagnetic waves using VNA indicated that there is an absorption of EM waves in the frequency range between 8-12 GHz with almost the same peak frequency for all four samples at 10.8 GHz with the absorption of around 5 dB. The existence of a weak ferromagnetic property can be detected clearly using HRPD. Neutron diffraction as a probe can observe the magnetic structure accurately even in a material having a weak ferromagnetic property.
 
Existing parking management approaches do not consider specific requirements, priorities, user comfort, or modes of use when allocating a parking spot in a large park. As a result, vehicles carrying multiple passengers but staying for a limited period often have to drive further, searching for a parking spot, which increases fuel consumption, emissions, waste of time, and discomfort of users due to extra walking distance. In this paper, we consider the need for both sustainability and comfortable livings in a future smart city and propose an adaptive-optimal scheme that takes advantage of parking efficiency based on the passenger information and flexibly provides the optimal parking spot to the individual. We presume that the management system has information about the number of users, user priority, and expected stay time when a car arrives or a parking request is made. The best parking slot is assigned based on the available parking slots and the given objectives, such as the shortest travel distance inside the parking zone for a low pollution, the shortest walking distance per user, or a combination of both with some trade-off. The decision process is fine-tuned using parking data obtained from a model of a large car park of a shopping complex, and the results of the proposed scheme are compared with other schemes. The findings indicate that overall time spent in the parking lot, as well as individual walking and travel distances, have significantly improved.
 
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Additive Manufacturing (AM), widely known as 3D printing, is a fabrication process to build 3D parts layer by layer directly from a virtual CAD model. It is an innovative technology, with the potential to revolutionize the manufacturing industry completely. It is possible to manufacture complex shaped parts, shortening production sequence, reducing time to market and allowing mass customization. As one of Industry 4.0 nine pillars, AM has promoted an extensive number of researches. Some of them identify organizational culture as a leading factor affecting its implementation in industries. Like any change within companies, organizational culture can be a decisive factor for the successful implementation of AM. However, few studies have thoroughly explored the subject to find which set of cultural characteristics can guide the whole organization. This research identifies, through a systematic literature review (SLR) based on the PRISMA Protocol, which set of cultural characteristics can guide the transition from conventional to AM technology. The systematic literature review was capable of identifying a set of 41 cultural characteristics, which the company should present to implement AM successfully. Knowing which cultural characteristics can help AM implementation companies will increase their chances of succeeding when moving towards AM technologies within Industry 4.0.
 
Present work describes the failure investigation of failed bolt of starboard rear mounting trunion of an aero-engine. Multiple fracture initiation points are noticed. This is a classic case of a single bending type of load initiating reversed bending fatigue as well as chevron pattern on the same fracture surface. Visually observed bending phenomenon supports the each type of failure mode. More interestingly, point of initiation of fast as well as the reversed bending fatigue failure is the same, although those two events have been found to be separate phenomena. It has been established that two different fatigue crack fronts, typical of reversed bending fatigue phenomenon propagated towards each other to make half of the cross-section fractured, while the another half failed by chevron patterned fast fracture. In this, the fast fracture of one half has preceded the reversed bending fatigue fracture of the other half, although the former is not responsible for happening of the later. Modes of fracture and factors influencing have been established in this article with emphasis on circumstantial evidence involving background information and visual examination, supported often by the open literature. Presence of cadmium (Cd) and its possible source, residence time and relative presence on differently fractured surfaces have offered important clues on establishing the sequence and relative inter-dependence of the said two fracture types. Presence of cadmium on the fracture surfaces, multiple crack initiation sites and numerous well-revealed secondary cracks on Branson cleaned fracture surface indicate that the cracks pre-existed on the material even before the cadmium plating and manifestation of chevron pattern is its extreme revelation. This pre-existing chevron pattern primarily aggravated the present failure through bending fatigue phenomenon in the later stages. Low alloy steel (ASTM grade 16) with presently used hardness (340 HV) level does not seem to suit the present application, as it is clear from its extreme brittleness as manifested by pre-existing cracks.
 
Failures of two power take off (PTO) shafts of an aircraft have been analysed. Two shafts, one each developed by two different manufacturers failed separately during power run endurance test conducted at room temperature and ambient normal atmosphere. In both the cases, cracks were observed on the outer diaphragm disc. One shaft showed cracking in the engine side, while the other one exhibited cracks in the aircraft mounting accessory gearbox (AMAGB) side. Chemical analysis, microstructure and hardness evaluation indicate that the diaphragm material of the shafts is Ti-6Al-4V alloy used in solution treated and aged condition, as per the desired specification AMS 4928. Microstructural in-homogeneity, possibly a result of improper forging, was observed in diaphragm material of both the shafts. Additionally, surface discontinuities induced by forging and subsequent insufficient machining were noticed on the diaphragms. The diaphragms failed by fatigue with cracks possibly nucleating at surface discontinuities. Discontinuities with lower availability in one shaft led to somewhat increased life (466 million cycles) as compared to the life (104 million cycles) of the other shaft. Another possible factor contributing to lower life in the later shaft is the presence of higher quantity of nitrogen rich inclusions. Controlling factor triggering the failure of diaphragm of shaft with lower life seems to be the available high stress level along the rim periphery, while that for shaft with higher life is presence of few localized sharp surface discontinuities.
 
This paper presents the failure analysis of aircraft antenna which is a sub-assembly of Traffic Collision Avoidance System (TCAS) used with Air Traffic Control (ATC) transponder. The base of the damaged antenna (metallic part) is made from Al-based alloy. The micrographs exhibit the typical solidification microstructure consisting of Al-rich matrix along with Si- and Mg-Si-Fe- rich phases. The antenna is coated with the paint consisting of three layers. First and third layers display the presence of Ti and C while second layer consists of Si, Cr and C elements. The small amount of oxygen is also present in all the three layers. The cracks are appeared in the central region of the fin due to impact of external objects (appears to be blankings and particles). Three types of foreign object damage particles are observed on the damaged / hit area. The antenna appears to be damaged during gale as a result of hitting of the large particles lying in aircraft parking area and aircraft engine blankings.
 
Participants' ages ranging from (25 to 65 years)
total of participants are 163, and their Job divided
Conflict in construction projects seems to be the reasons of high project cost, project delays, lower productivity, loss of profit, damage business relationships and dispute on the team. Effective functioning requires commitment of at least several key personnel to get the venture runs effectively even with the presence of distinctive intrigue. When individuals of fluctuating foundation meet-up on a task group, strife is unquestionably present there. As the individuals inside the venture alliance are interrelated, intrigue impacts and clashes are not uncommon within their activities. This study therefore sought to discover the causes of these conflicts in the construction sector and the manner by which these conflicts can be effectively resolved. Here a quantitative survey-type study has been carried out on construction project in Kuwait international airport for conflict management. One hundred eighty eight questionnaires have been distributed, fourteen of them have been lost and eleven of them have not been answered. The responses of 163 participants have been analyzed with the Statistical Package for Social Scientists (SPSS). This study showed that the general causes of conflict are predominantly create conflicts. Inadequate communication and contradicting instructions according to the results are the leading causes of conflict. The effects of conflict on project mainly include project delays, ineffective construction and reduced productivity, etc. The findings revealed that participants in the study prefer the role of collaborating and compromising styles in solving conflict of on-site construction. Every project starts and ends with communication, so communication is the life wire of all construction projects. To cure the communication problem, the study suggests strategies like Team Meeting Discussions, Site Review Meetings, and Project Status Reporting platform to manage the conflict and reduce the dispute of construction projects.
 
High speed machining has many advantages in reducing time to the market by increasing the material removal rate. However, final surface quality is one of the main challenges for manufacturers in high speed machining due to the increasing of flank wear rate. In high speed machining, the cutting zone is under high pressure associated with high temperature that lead to increasing of the flank wear rate in which affect the final quality of the machined surface. Therefore, one of the main concerns to the manufacturer is to predict the flank wear to estimate and predict the surface roughness as one of the main outputs of the machining processes. The aim of this study is to determine experimentally the optimum cutting parameters: depth of cut, cutting speed (Vc) and feed rate (f) that maintaining low flank wear (Vb). Taguchi method has been applied in this experiment. The Taguchi method has been universally used in engineering analysis. JMP statistical analysis software is used to analyse statically the development of flank wear rate during high speed milling of hardened steel AISI D2 to 60 HRD. The experiment was conducted in the following boundaries: cutting speed 200-400 m/min, feed rate of 0.01-0.05 mm/tooth and depth of cut of 0.1-0.2 mm. Analysis of variance ANOVA was conducted as one of important tool for statistical analysis. The result showed that cutting speed is the most influential input factors with 70.04% contribution on flank wear.
 
Heat produced at the tool-chip interface during high speed milling operations have been known as a significant factor that affect to tool life and workpiece geometry or properties. This paper aims to investigate cutting temperature behaviours of AISI H13 (48 HRC) under high speed machining circumstances during pocketing. The experiments were conducted on CNC vertical machining centre by using PVD coated carbide insert. Milling processes were done at cutting speeds 150, 200 and 250 m/min and feed rate were 0.05, 0.1 and 0.15 mm/tooth. Depths of cut applied were 0.1, 0.15 and 0.2 mm. Tool path method applied in this experiment was contour in. Results presented in this paper indicate that by increasing cutting speed the cutting temperature is lower than low cutting speed. However, by decreasing feed rate leads to cutting temperature low. Cutting temperature phenomena at the corner of pocket milling were also investigated. The phenomena showed that cutting temperature tends to decrease a moment when cutter comes to the corner of pocket and turning point of tool path and increase extremely a moment before leaving the corner and turning point.
 
Ti-alloy represents a significant metal portion of aircraft structural and engine components for high reliability. Surface integrity is one of the most relevant parameters used for evaluating the quality of finish machined surfaces. The residual stress and surface alteration with each layer and depth of work hardening by machining Ti-alloy are critical due to safety and sustainability concerns. Residual stresses, white layers well microstructural alterations can be figured out to improve surface qualities of end products. Many parameters such as cutting speed, feed rate, depth of cut affect the machined surface quality particularly surface fisnish. This article provides details of lathe turning for investigation of surface roughness for varying cutting parameters. An attempt has been made to search for best ranges of cutting regimes that could produce best surface roughness for machining Ti-6Al-4V alloy using uncoated cutting tool. Taylor-Hobson device is used to measure the surface roughness on the machined workpieces. In this project three series of experimentaions were carried out and a total of 16 steps of operations in each series are performed for determining the surface roughness. Real life experimental investigation has allowed to express the results in graphical form (using tabulated data) that has suggested best ranges of cutting regimes (parameters) for obtaining the best ranges of surface roughness for machining Ti-6Al-4V using uncoated carbide tool. The work has indicated to investigate the science of bulk flow, particularly the plastic deformation, for difficult to machine materials, at a much higher temperature. Behaviour of cutting tool materials for high speed cutting is another isuue to develop.
 
High temperature generated and stresses induced as a result of turning of Ti6Al4V results in poor surface finish. The aim of this study was to investigate the effect of coolant temperature on the surface roughness of Ti6Al4V which is a core material used as an implant. A cooling system was developed to reduce the temperature of the coolant (soluble oil) from room temperature to 2oC. Ti6Al4V was turned in dry and cooled (at temperatures 5, 7, 9 and 11 oC) conditions. The experiment was designed using central composite design of (Response surface methodology) Design Expert 11.0 to generate an array and optimize the machining parameters. The machining parameters used were cutting speed, feed rate, depth of cut and coolant temperature. Results analyses show that cutting speed and depth of cut had considerable effect on surface roughness of Ti6Al4V. Surface roughness reduced when coolant temperature was reduced. The results of this study shows that turning Ti6Al4V at a very low cutting temperature will ensure a better surface finish.
 
The densification and mechanical properties of alumina ceramics were investigated via two-step sintering (TSS) with different holding time. The alumina ceramics were sintered at 1450 °C for 1 min during the first stage, followed by sintering at 1350 °C with different holding times (2-24h). Conventional sintering (CS) was also performed on the alumina ceramics at 1450 °C for 2 h for comparison purpose. It was found that dense alumina with a relative density above 98% could be attained when TSS with a holding time of more than 12 h. The samples exhibited Vickers hardness between 5-8 GPa and fracture toughness of about 6 MPa.m1/2. In contrast, conventional sintered alumina yielded low relative density (85%), large grain size (2 μm), low Vickers hardness (4.23 GPa) and fracture toughness (4.73 MPa.m1/2). This study revealed that TSS is a viable approach in aiding densification, suppressing grain growth, and improving the mechanical properties of alumina ceramics.
 
Figure1: Photo-micrograph of (a) aluminium powder and (b) CNT [3]. 
Carbon nanotubes (CNT) is a promising fibrous materials for development of nanocomposite especially aluminium (Al) matrix nanocomposites as CNT exhibited extraordinary mechanical properties and high aspect ratios. The dispersion is the main factor for a quality CNT-Al nanocomposite that affects the uniformity in mixture leading to the enhanced mechanical and wear behaviour. The present study emphasizes on the characterization of carbon nanotube dispersion by means of field emission scanning electron microscope after synthetization of new nanocomposite. The mixing of the reinforcement and matrix powders was performed in ball mill for 2 hours at 250 rpm. The result shows the homogeneous distribution was observed from the experiment. The morphological characterization under FESEM provides insight features of CNT-Al nano-composite with the ball milling parameter on the sintering.
 
Density variations for different percentage compositions of aluminium-aluminium oxide composites before and after sintering (Sintering temperature: 550 o C) 
Density variations for different percentage compositions of aluminium-aluminium oxide composites before and after sintering (Sintering temperature: 580 o C) 
Hardness variations for different percentage compositions of aluminium-aluminium oxide composites (Sintering temperature: 550 o C). 
Hardness variations for different percentage compositions of aluminium-aluminium oxide composites (Sintering temperature: 580 o C) 
In this study, aluminium-aluminium oxide (Al-Al2O3) metal matrix composites of different weight percentage reinforcements of aluminium oxide were processed at different sintering temperatures. In order to prepare these composite specimens, conventional powder metallurgy (PM) method was used. Three types specimens of different compositions such as 95%Al+5%Al2O3, 90%Al+10%Al2O3 and 85%Al+15%Al2O3 were prepared under 20 Ton compaction load. Then, all the specimens were sintered in a furnace at two different temperatures 550oC and 580oC. In each sintering process, two different heating cycles were used. After the sintering process, it was observed that undistorted flat specimens were successfully prepared for all the compositions. The effects of sintering temperature and weight fraction of aluminium oxide particulates on the density, hardness and microstructure of Al-Al2O3 composites were observed. It was found that density and hardness of the composite specimens were significantly influenced by sintering temperature and percentage aluminium oxide reinforcement. Furthermore, optical microscopy revealed that almost uniform distribution of aluminium oxide reinforcement within the aluminium matrix was achieved.
 
A composite material is a combination of two or more chemically distinct and insoluble phases; its properties and structural performance are superior to those of the constituents acting independently. MMCs are made by dispersing a reinforcing material into a metal matrix to improve their properties. They are prepared by powder metallurgy and casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composite. In this work a composite is developed by adding Mango seed shell Ash (MSSA) particulate in Al- Si-Mg Alloy by mass ratio 5%, 10%, 15% and 20%. The composite was prepared by stir casting technique. It is proposed to use this material for production of motorcycle wheel hub which are subjected to continuous wear as the hubs are in direct contact with the brakes and rotating sprockets. The MSSA, was characterized using X- ray fluorescent (XRF). The result reveals SiO2, has the highest percentage composition followed by CaO, Al2O3, Fe2O3 and Mg2O as major phases. The presents of these hard constituent compounds suggests that the mango seed shell ash can be used as particulate reinforcement in various metal matrices since the chemical composition has similarity with the XRF analysis of Periwinkle shell ash, rice husk, fly ash, and bagasse ash currently used in metal matrix composite. Mechanical tests such as hardness test and impact test were conducted. The results revealed that increase in the percentage of MSSA progressively increased the hardness of the material from 5% wt to a maximum hardness of 43.2 HV at 15% addition of MSSA. This represents a 26.16% improvement over the unreinforced alloy. However, the impact energy progressively decreases of the material from 5%wt of MSSA and later increased to optimum energy at 15% addition of MSSA. From the results it is concluded that composite material such as Al- Si-Mg/ MSSA is one of the options as a material for production of motorcycle hub. The wear test of the composite was then carried out using Taguchi design to optimize the range of MSSA from 5% wt -15% wt., Sliding speed of 5cm/s -20cm/s, sliding distance from 50m to 200m, and the load of 2N, 4N, 6N, & 8N respectively. Analysis of the result of SN ratio for wear rate shows the optimum wear resistant value is in the combination of Load=4N, sliding speed = 10cm/s sliding distance=200m and MSSA=15 wt% These also correspond with the analysis of wear maps & wear rate presented in the diagrams of dynamic friction coefficient (COF) for Al-Si- Mg/ MSSA Composite.
 
Preheating and welding sequences 
Fractured surface and microstructure of typical tensile specimen. Preheating and GTAW at 85 A AC, 260 mm/min; Keller etching. 
Factorial experiment. Four point bending test results without replicate. 
Fractured surface and microstructure of typical four-point bending specimen. Preheating and GTAW at 85 A AC, 260 mm/min; Keller etching. 
Four-point bending test data for three replicates at optimal welding conditions. Preheating following by welding at 85A AC, 260 mm/min. 
Weldability of aluminum-based metal matrix composite A359/SiC/10p using gas tungsten arc welding and R356.0 filler material is investigated. The welding current, welding speed, and preheat temperature affect the weld quality significantly. Finite element analysis is successfully applied to map the weldment temperature during preheating and welding. During mechanical testing of welded specimens, a crack propagates in the parent composite or in the weld, but not in the stronger zone between the weld and the parent material. The weld region contains reasonably uniform distribution of SiC particles due to high viscosity of the molten weld and its fast cooling rate. Proper control of heat input and addition of silicon-rich filler material hinder the interface reaction between aluminum matrix and the reinforcing SiC particles, and successfully suppresses the formation of harmful aluminum carbide flakes in the weld. The average tensile and flexural strengths of optimally welded specimens approach those of the parent composite while its ductility exceeds that of the parent material.
 
Rotary hammer forging process is getting popular since it has many advantages comparing to the conventional forging process. The mechanism of the movement in term of orbital motion of the conical upper die become concern of this research. This article present the three stages of the modelling of the rotary hammer forging. The first stage is the development of the orbital motion of the conical upper die. Three-dimensional CAD model of the conical upper die was developed to determine the orbital motion as a function of the four parameters: Nutation, Precession, Spin and Rocking-Die mechanism. A reasonably accurate design of the conical upper die and the workpiece had been developed based on motion because of interaction of conical upper die and upper part of workpiece geometries. The behaviour of orbital motion with any active combination of those four parameters was observed. The second stage was the development of the conical upper die with the specific feature in order to generate a product with an unsymmetrical shape of upper part of the product. The sequence and mechanism of the formation of the upper part of product were generated. The third stage was the analysis of the stress strain state during the formation of the upper part of the workpiece. An elastic-plastic, dynamic analysis of 3D rotary hammer forging mechanism with the concern at the workpiece and their interaction with a model of dies have been performed. Verification of the indentation mechanism of the rotary hammer forging had been done by validating the result with the existing experimental results.
 
Artificial intelligence (AI) is the ability of a computer program or machine to think or learn that possess human-like intelligence. These computing devices use this intelligence to provide services such as speech recognition, natural language processing and identifying disease in healthcare. To work efficiently, AI requires adequate data that is used to train systems. The efficiency of any AI system depends on the availability of this data. This article is mainly focused on recent advents in the technology of Artificial Intelligence. The importance of AI in healthcare is identified and described in this report. The applications of Artificial Intelligence in healthcare such as clinical care, medical research, drug research and public healthcare are briefly discussed here. The purpose of this article is to demonstrate that artificial intelligence is being used in all domains of life and particularly in the field of healthcare. This report presents the role of Artificial Intelligence in healthcare.
 
Experimental results and S/N ratios of developed samples
Results of Grey relational analysis (GRA)
Resulting factor effects of process parameters
ANOVA for Friction Coefficient
ANOVA for wear rate
Over many years, asbestos has been used as reinforcement material in the production of brake pads production but it has lost favour due to its carcinogenic nature, as a result, there is need to investigate other possible substitute which can offer similar tribological properties as the carcinogenic material (asbestos). Several works has been carried out using different reinforcement material with the aim of finding a possible replacement for asbestos. In this work, Rule of mixture (ROM) was ustlised for sample formulation and the tribological properties of natural based material (coconut shell and seashell) were investigated using experimental design (response surface methodology) and multi-response optimisation technique (Grey relational analysis). The multi-response performance of the formulated brake pads samples was compared with a commercial brake pad sample. The research findings revealed that sample can be produced using 52% reinforcement, 35% binder, 8% abrasive and 5% friction modifier while the Grey relational analysis (GRA) showed that optimum multi-response performance of the developed coconut shell based sample can be achieved using MP, MT and CT and HTT of 12MPa, 100 oC, 6mins and 2hrs respectively while that of the developed seashell based brake pad can be achieved using MP, MT and CT and HTT of 10MPa, 160 oC, 12mins and 2hrs respectively. Also, the Analysis of variance (ANOVA) results show a percentage error of less than 5% indicating minima noise effect. In addition, the optimized coconut shell-based brake pads falls within the category of class H (µ >0.55) type of brake pads while seashell based sample falls within the class G (µ: 0.45-0.55) type of brake pads. It therefore concluded that the use of coconut shell can serve as a better substitute for asbestos-based brake pads.
 
The aim of this research was to evaluate the level of greenhouse gas emission from broiler chicken farming industry in Malaysia. In order to achieve that, Life Cycle Assessment method was chosen as a framework to complete the task. A case study was conducted at a broiler chicken farm to gather the data and information related to the broiler chicken production. Cradle-to-gate assessment including distribution stage was conducted based on the ISO14040/1044 guidelines. Inventory data for this case study was gathered in collaboration with one of the selected case study broiler chicken farm company. Greenhouse gas emission that consists of several most affected gases such as carbon dioxide, methane and nitrous oxide was studied. Result shows that the highest carbon dioxide emission came from manure, which accounted for 1,665,342 kg CO2 equivalent per total broilers while the highest methane emission came from feed, which accounted for 126,207.84 g CH4 equivalent per total broilers. For nitrous oxide emission, the highest values came from bedding which accounted for 20,316.87 g N2O equivalent per total broilers in the commercial modern broiler chicken farm. In this case study, it can be concluded that manure gives the most prominent effect to the greenhouse gas emission followed by feed and bedding materials.
 
Present Atmospheric Water Generation (AWG) systems are useful for providing water in areas with limited water supplies. Many industrial AWG systems use VCR (vapor-compression refrigeration) to achieve a large amount of cooling to extract liquid water out of the air. These systems require large amounts of energy to operate, usually in the form of diesel or AC-powered generators. The systems also have many moving parts that require maintenance and use refrigerants that can leak and cause problems with the environment. An alternative AWG solution is to use DC-powered Peltier devices (thermoelectric coolers) to reduce the temperature of condensation plates to extract water from the air. This solution eliminates the issues with traditional industrial AWG systems since the Peltier devices are solid-state, have very long mean-time between failure (MTBF) performance, and can be powered by solar panels that eliminate the need to burn hydrocarbon-based fuels or have access to a reliable power grid. Also eliminated is the need to use chlorofluorocarbon (CFC) or hydrochlorofluorocarbons (HCFC) refrigerants that have been shown to deplete the ozone layer. This paper will present methods to improve the efficiency of the thermoelectric coolers by more efficiently extracting heat from the hot side of the device. This efficiency will be quantified by evaluating the coefficient of performance (COP) of the thermoelectric cooler under the various operating conditions. Different combinations of conductive heat transfer using aluminium heatsinks, convection heat transfer using forced airflow, and phase change heat transfer using copper heat pipes filled with distilled water will be investigated and evaluated.
 
Bone drilling operations are carried out in hospitals in different surgical operations worldwide (e.g. orthopedic surgeries and fixing bone breakages). It is considered one of the most sensitive processes in biomedical engineering field. During drilling, the most critical problem is the rise in the temperature of the bone above the allowable limit. A Study showed that the allowable limit that must not be exceeded is 50oC. Moreover, if this limit is exceeded, the bone may sustain serious damage, namely, thermal necrosis (cell death in bone tissue). The research in this paper focuses on reducing the temperature rise during bone drilling. A study was conducted to observe the effect of the drill rotational speed, feed rate and drilling depth on the drill bit temperature during drilling of goat and cow bone. Experimental methods were engaged to optimise the drilling parameters in order to achieve an accepted level of drill bit temperature.
 
Comparison between parallel and serial manipulator
Technical specifications for ABS used in this research
Arduino Uno R3 Technical specifications
Sample of the (a) coding and (b) GUI for the CNC system 
Summary of platform algorithm test results
CNC machine is the one of the major reasons for industrial advancement in recent decades for its ability of producing accurate parts. The most commen CNC machines are of 3-axis and adopted widely in the industrial sector. However, for producing more complicated parts 5-axis CNC machines are required. Although the introduction of the 5-axis machine came after the 3-axis CNC machine has established itself and many manufacturers did not make the move toward the newer model and its high pricing compared to the 3-axis model did not help either. In this time the development of a fixture or a platform to help transfer the 3-axis to a 5-axis to some degree. This paper discusses the concept of a programmable fixture that gives 3-axis CNC machine the freedom to act in similar manner as the 5-axis. The paper describes the mechanism with some initial results of the testing. Result showed that the platform moves in translation manner with an average error of 5.58 % and 7.303% average error for rotation movement.
 
This research reports on the suitability of Agricultural bi-products as low temperature thermal insulating materials to replace synthetic insulating materials like polyurethane used in food warmers and ice coolers. Coir and sugarcane bagasse chosen for this research was based on literature review and local availability of materials. Coir was obtained from Badagry, Lagos State and Sugarcane bagasse obtained from Batati, Niger State, the materials were washed, sun dried for three days and cut into smaller pieces before being blended into smaller particles using an electric blender. The blended materials (Coir and Bagasse) were sieved into two different sieve size of 0.5 mm and 1.0 mm respectively. The particles sizes were then combined into blend ratios of 50/50, 60/40, and 70/30 using Gum Arabic as binder. Thermal conductivity test showed that 1.0 mm particle size coir mixed with sugarcane bagasse has the lowest thermal conductivity of 0.01467 W/mK whilst that of 0.5 mm particle size has thermal conductivity of 0.01472 W/mK this is lower compared to the measured thermal conductivity of the polyurethane control sample of 0.01832 W/mK. Sample F (1.0 mm particle size,70% coir and 30% bagasse) with a thermal diffusivity of 5.15 m²/s, water absorption capacity of 410 %, UTS of 0.219 MPa, Compressive strength of 0.583 MPa, Specific heat capacity of 1141.3 J/kgK and thermal resistivity of 68.16 W/m/K is most suitable replacement for polyurethane as low temperature thermal insulator. This is corroborated by the performance evaluation test with carried out between polyurethane lined food warmer and bio-composite lined food warmer. The two test samples have close ice melt rate values and the polyurethane slightly edge the Bio-composite insulating material by 1.2 % in efficiency. The edge in efficiency can be accepted as all materials used in the development of the bio-composite insulating material are completely bio-degradable and environmentally friendly.
 
Experimental parameters and responses
Analysis of Variance of Flexural Strength Data
Shows the relationship of volume fraction on flexural strength of specimens with fiber length 127 mm Figure 4: Shows the relationship of volume fraction on flexural strength of specimens with fiber length 63 mm 
Shows the relationship of fiber length on flexural strength of specimen with volume fraction 40%. 
Natural fiber such as kenaf, sisal, pineapple leaf and banana are growing popular nowadays due to its favor over traditional glass fiber and inorganic material. It is a renewable resources and abundantly available in the market. The composites made of natural fiber are economical, lightweight and environmental friendly. This study works on producing a composite based on the Banana fiber reinforced epoxy resin by using the method of Vacuum Infusion and Hand Lay-up. Banana fiber will be treated with Sodium Hydroxide (NaOH) and water solution for 1 hour and then dried in the oven for 24 hours at 100°C. The composite will be produce based on different fiber volume fraction of 20% and 40% as well as different fiber length of 127mm, and 63mm. In Vacuum Infusion process, a mold made of aluminium have been manufactured according to the size of specimens of 127mm x 12.7mm x 3.2mm in dimension will be used in the preparation of specimens. The specimens of different volume fraction and fiber length produced by vacuum infusion and hand lay-up method will be mechanically tested through flexural test. The highest flexural strength is the specimen made by vacuum infusion process with 40% volume fraction and 63mm fiber length, which is 136.27MPa while for the hand lay-up process, the highest flexural strength is 80.71 with 40% volume fraction and 63mm fiber length.
 
Bangladesh has an impressive track record of development and has been among the fastest growing economies in the world over the past decade, supported by a demographic dividend, strong ready-made garment (RMG) exports, remittance, and stable macroeconomic conditions. With the growth of populace and the living standards, the goods and energy consumption in Bangladesh are seen to be increased which rises the waste generation. Thus, municipal waste management (MSW) and energy supply are becoming the great challenges for Bangladesh. Waste to energy (WTE) conversion technologies would be a very timely solution to an ever-growing problem. These technologies are environment-friendly and cost effective; however, these are not popular within the developing country Bangladesh. This paper discusses current waste status, significant progresses and future prospect of solid waste management process as well as evaluates the best possible WTE technology suitable for Bangladesh. It is found that Bangladesh produces approximately 13,332 tons of MSW per day in which almost 26% and 12% of total wastes are generated by its capital city, Dhaka and Chattogram, respectively. The incineration process for electricity production is seen to be the most effective WTE technology for Chattogram city. For instance, for one ton of MSW, the incineration process can provide 0.585 MWh electricity and 1.742 MWh heat with an emission factor of 0.28 ton of CO2. With an average plant capacity cost of 2.1 USD which is lower than other WTE technologies. Therefore, the incineration can be utilized as the most effective WTE technology for major cities in Bangladesh.
 
Solid waste is an inevitable by-product of human beings, animals and also of industrial-commercial activities. Obviously solid waste creates a greater problem to the environment, if it is not properly managed. Bangladesh being a heavily populated country needs to pay adequate attention to waste management. Waste generation in Bangladesh is increasing because of rapid urbanization and economic development of the country. At present, total solid waste generation in Bangladesh is around 27000 tons/day and in the four important city corporations is about 13,332 tons. Particularly in Dhaka city, it is around 7500 tons/day. This amount is likely to reach about 47000 tons per day in entire Bangladesh and 15000 tons per day for Dhaka city alone by 2030. At present, landfilling is the only method for disposal of heterogeneous waste stream and there are three landfills in Dhaka City. Most of these landfill sites are in open dumps polluting land, water and air. Development of any new landfill site is near to impossible due to land scarcity and increasing of land prices especially in Dhaka City. Improperly disposed waste is posing serious health implications to the people and it may transmit various diseases especially by non-degradable wastes like polythene. Rather, a proper Segregation system to recover of resource from plastic wastes can play a very important role in mitigating the difficulties of solid waste that can act as a raw material for product design in Bangladesh too. Therefore, a comprehensive study report followed by a model of plastic waste segregation system for Bangladesh has been highlighted in the paper.
 
The present study was undertaken to evaluate the performance efficiency of an Effluent Treatment Plant (ETP) of a Textile industry located at Tongi, Bangladesh with biological treatment (BT) and Membrane Bio-Reactor (MBR) with an average inflow of 300 m3/hr. The effluent samples were collected from the inlet and outlet of the ETP on a weekly basis for a 4 weeks’ period and were analysed for key parameters such as colour, temperature, total suspended solids (TSS), Total Dissolved Solids (TDS), pH, Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), and Chemical Oxygen Demand (COD). In this study, it was observed that the colour of the effluent in the inlet was dark blue and after multiple unit treatments of the colour’s final outlet the discharge, water colour was very light purple. The temperature was varied from 32.2⁰C to 34.33⁰C. The TDS was varied from 1252.5 mg/l to 1087.5 mg/l and the percentage removal efficiency of TDS was varied from 21.47% to 42.7%. The TSS was varied from 4 mg/l to 4.5 mg/l and the percentage removal efficiency of TSS was varied from 98.48% to 98.21%. The pH value was varied from 6.48 to 7.63. The DO value in the inlet was varied from 6.47 mg/l to 6.775 mg/l. The BOD was recorded from 12.75 mg/l to 17.75 mg/l and the percentage removal efficiency of BOD was varied from 89.92% to 87.24%. The COD was varied from 33.75 mg/l to 34.25 mg/l and the percentage removal efficiency of COD was varied from 91.11% to 90.5%. It is conjectured that the values of the measured parameters are seen to be within the permissible limit as per the standard of the Department of Environment (DoE) of Bangladesh.
 
The internet has contributed significantly by changing how we interact with other people and how we execute business today. By virtue of the internet, electronic commerce has emerged, facilitating business to manage their customers and other corporations inside more effectively and outside their industries. The industry which is applying business transaction using this new communication channel to reach its customers is the banking industry. The electronic banking system addresses several emerging trends such as customer's demand for anytime, anywhere service, product time-to-market imperatives and increasingly complex back-office integration challenges. The challenges that oppose electronic banking are concerns of security and privacy of information. This paper will first discuss the current forms of security threats in the internet banking; secondly, it will investigate weaknesses in the current information security protocols of the internet banking. Thirdly, it will propose an enhanced information system security for internet banking.
 
Due to superior mechanical and metallurgical performance, Nickel-base Alloys 617 and 276 have been considered as structural material for used in complex and stochastic applications. Surface irregularities such as cracks in the material may be vulnerable to the structural integrity of an engineering component. Void growth behavior is however analyzed using crystal plasticity theory in nickel-based super alloys. Elastic-plastic fracture mechanics base single compact tension specimen has been used to determine the J1C value as a function of temperature of austenitic Alloy 617 and 276 for ductile crack growth behavior. Crack formation is appropriately explained through crack nucleation based on the microstructural heterogeneity properties of the alloys. Alloy 617 showed a fair increased resistance to fracture as temperature increased from ambient to 5000C for duplicate testing, satisfying the EPFM criteria. Whereas the J1C values of Alloy 276 increased gradually with temperature up to 300° C and due to enhanced plasticity in the vicinity of 4000 C this alloy shows inconsistent value. Two-dimensional simulation of J-integral model of these nickel base super alloys at temperature range 1000C to 5000 C has been proposed. Particular focus is given on the load line displacement where crack propagation occurs during the loading phase only. Path independency of J-integral has been clearly demonstrated for both the alloys up to 3000 C employing finite element analysis meshing with 1922 quadrilateral 2D solid elements in ANSYS. Cracks are typically initiated in relation to the level of strain range. A higher strain range initiates cracks due to precipitate shearing, whereas a low strain range initiates cracks with oxidation reactions and carbide diffusion. The values of K1C and crack tip opening displacement for these alloys have been calculated based on the experimental data. Moreover, fracture morphology in the loading and unloading sequences near the crack tip has been analyzed by SEM.
 
Liquefied petroleum gas (propane or butane) is a colourless liquid which readily evaporates into a gas. It has no smell, although it will normally have an odour added to help detect leaks. Liquefied petroleum gas is stored and handled as a liquid when under pressure inside an LPG cylinder. Liquefied petroleum gas cylinders are subjected to various tests to ensure their compliance requirements as per standard. This research studied the durability of welding and performance of base metal of LPG home cylindrical in Kurdistan region. The experiments were carried out on an unformed plate and three types of LPG cylinder designated as A, B, and C and D. In this research standard tests for LPG cylinders were conducted. Three samples were extracted from each of LPG cylinders and unformed plate for each of tensile test, bending test and hardness test according to ISO 6892-2016 and ASME standards to examine the mechanical properties. In addition, chemical compositions also were carried out. These values are compared with standard.
 
Cross sections C, I and T of beam 2.2.1 Torsion According to Kollar and Springer [12], for an open-section beam under torsion, the in-plane forces per unit length which are Ny, Nxy and moment per unit length My are zeros. Thus, the expressions for Nx, Mx and Mxy in matrix form is: 
An educational software which can aid students in stress analysis of thin wall open sections made of composite material has been developed. The software enables students to easily calculate stresses of thin wall open section and evaluate the stresses in each ply. Results obtained through this software have been validated against ANSYS V14. The software is intended to be used as a resourceful tool for effective teaching and learning process on thin-walled structures, aircraft structures and composite structures courses.
 
Optimisation is a technique or procedure to find the optimal or feasible solution whether it is to minimise or maximise by comparing other possible solutions until the best solution is found. Nowadays, many optimisation algorithms have been introduced due to the advancement of technology such as Teaching Learning Based Optimisation (TLBO), Ant Colony Optimisation (ACO), Particle Swarm Optimisation (PSO) and the Bees Algorithm. The Bees Algorithm is considered as one of the best optimisation algorithms because it has been successfully solved different type optimisation problem from in various field. It is inspired by the foraging behaviour of honey bees in nature. This study applies the Bees Algorithm to minimise the mass of disc clutch brake in its design. To find the optimal solution for the multiple disc clutch design, the Bees Algorithm will be used and expected to give better result compared to other optimisation algorithms that already have been used.
 
Two separately failed electrical connector pieces during a vibration test were received for failure analysis. Chemical composition, hardness values and microstructures of the each of the connector material indicate that the material of construction is a die cast aluminium-silicon type of alloy, closely matching with the standard ANSI/AA B380 alloy. Intergranular and faceted fracture features are observed and failure mechanism is found to be fatigue dominated. The connectors failed by impact fatigue arising out of the loosening of the connector assembly. This has happened by cavity formation and/or growth related microstructural degradation processes. Initial casting pores as well as microstructural degradations such as interconnected pores have developed in service and their successive growth, decohesion and interconnection of each of primary Si particles and Al-Fe-Mn precipitates (along precipitate-matrix interface) have led the initiation of the crack under fatigue loading. Brittle as-cast microstructure (as typified by the precipitate-matrix interfacial cracking), existing vibratory loading and absence of any rise in temperature in the system have assisted the initial cavity (crack) formation and/or growth. Moreover, initial fitment related looseness is an additional factor in initiating and propagating this damaging mechanism.
 
Conduction heat transfer in gaps containing many porous objects has not been widely discussed, even though there are several applications. This study aims to determine the mechanism and calculate conduction heat transfer in porous objects and whether there is a change in the thermal conductivity value. The research started from a mathematical model with a horizontal medium, and the results were matched with the simulation results. Porous objects contain water that can evaporate. This study used clove buds stacked with a certain thickness which caused porous between the piles of cloves. So, this research uses several heat transfer formulas related to porous media. Then a new formula is obtained to get the thickness of the pile of cloves based on the amount of porosity of objects and the porosity between the piles of objects.
 
Gold nanoparticles (GNP) acquire unique properties that have made significant contributions to clinical and non-clinical fields, specifically in the application of GNP’s for designing biosensor devices in which exhibit novel functional properties. Many properties of GNP’s are reviewed in this literature including optical properties, biocompatibility, conductivity, catalytic properties, high surface-to-volume ratio, and high density of the GNPs, that make them excellent in the application of constructing GNP-based biosensors. This literature review covers a specific comparison between the optical, electrochemical, and piezoelectric biosensors, as these are the three most common GNP-based biosensors. Optical biosensors are optimal due to their ability to cater to surface modification, which then leads to the ability for selective bonding. Furthermore, with the use of GNP and the sensor's non-invasive and non-toxic method of use, high-resolution images and signals can be formed. The sensitivity and specificity of electrochemical biosensors with the conductivity of GNPs, the electrodes of this stable biosensor can detect tumour markers in the human body. Piezoelectric biosensors are mass sensitive sensors and with the use of GNP, it amplifies the changes in mass. Through this, these sensors progress to be immunosensors which determine microorganisms and macromolecular compounds. As well, this review will conclude with an outline of present and future research recommendations for real-world application of the three GNP-based biosensors discussed.
 
Efficiency and durability are critical issues that affect widely-adopted aerofoil-power generator as a sustainable source of electrical power. Even though high wind power density can be achieved; installing wind turbines in desert condition has difficulties including thermal variation, high turbulence and sand storms. Sand blasting on turbine blade surface at high velocities causes erosion resulting turbine efficiency drop. Damage-induced erosion phenomena and aeroelastic performance of the blades needed to be investigated. Suitable coating may prevent erosion to a great extent. A numerical investigation of erosion on NACA 4412 wind turbine blade has been performed using commercial computational fluid dynamics software ANSYS FLUENT 14.5 release. Discrete phase model (DPM) has been used for modelling multi-phase flow of air and sand particles over the turbine blade. Governing equations have been solved by finite volume method (FVM). Conventional 30-70% glass fibre resin and non-conventional jute fibre composite have been used as turbine blade material. Sand particles of diameter have been injected from 20, 30, 45, 60 and 90 degree angles at 500C temperature. Erosion rate, wall shear stress and strain rate have been calculated for different wind velocities and impingement angles. Simulation results for higher velocities deviate from the results observed at lower wind velocities. In simulation, erosion rate is highest for impingement angle at low wind velocities, which has been validated by experiment with a mean absolute error (MAE) of 5.56%. Erosion rate and wall shear stress are higher on jute composite fibre than glass fibre resin. Developed shear stress on wind turbine blade surface is highest for impingement angle at all velocities. On the other hand, exerted pressure on turbine blade surface is found highest for 9 angle of attack. Experimental results, with or without Titanium nitride(TiN) nano-coating, also revealed that surface roughness augments with increasing impingement angles. Nano-coating (TiN) by RF sputtering technique reduced the surface roughness significantly as oppose to uncoated samples. Highest roughness has been observed on uncoated blade surface collided with 0.3-0.69 mm diameter brown aluminium oxide particles.
 
The alternative energy generation sources have increased drastically from centralized systems to distributed systems which increases the stability of energy distribution management systems and reduces the distribution cost as well. On the other hand, it reduces the probability of major area electricity blackout chances and decreases the energy distribution loss. For proper distribution and management of energy, there are different types of advanced technologies like artificial intelligence, and the Internet of Things (IoT) available, but a blockchain automated system is one of the best choices and is highly recommended. Various aspects of blockchain technology and energy management system have been discussed in this review paper where a total number of 423 journal papers, articles, and online information sources have been reviewed in the initial stage, and finally, 63 published research articles have been selected for review. There are several topics, including technology overview in energy management systems, blockchain application of energy trading, blockchain technology implementation challenges, distributed energy management system with Ethereum, and a conclusion with some recommendations have been discussed. Blockchain and Distributed Ledger Technology (DLT) are highly transparent, authenticate, and secure systems that can be used for distributing the energy between distributor and consumer without an intermediator which increases the overall efficiency of the system. This paper aims to highlight the blockchain and distributed ledger technology and how it works as well as optimize the transaction processing cost among the participants of the consortium network. This paper will make a significant contribution to the new research work and in the field of energy management systems.
 
General overview of steam boiler (Watt, 2017) 2.1.1 Boiler Mountings Mountings are crucial, without which the operation of boilers is unsafe. Proper maintenance and care of the mountings is important for the safety of both the boiler and the personnel and to maintain optimum operating condition of the boiler (Sadath, 2018). The boiler mountings are the part of the boiler and are required for proper functioning. In accordance with the Indian Boiler regulations, of the boiler mountings is essential fitting for safe working of a boiler. 1. Safety valves 2. Water level indicators 3. Water level controller 4. Water level alarms & cut-out assembly 5. Remote water level transmitter 6. Main steam outlet valve 7. Pressure gauge with cock & Pressure switches 8. Feed water valves 9. Burner assembly 10. Air vent 11. Water sampling valve
Lifetime likelihood of failure under preventive maintenance (Daley, 2008)
Research methodology
Schedule of preventive maintenance of steam boiler (Mobley, 2002)
Research gap analysis based on literature review
In Kuwait, industrial boilers are used extensively in food, chemical, oil and gas, textile, pharmaceutical, power plant sectors for generation steam. As a crucial item in industries, its maintenance is of utmost importance. As there are two main maintenance approaches such as reactive maintenance and preventive maintenance, the application of a typical maintenance is definitely based on types of application, safety concern, and cost benefit ratio. If a boiler is down for few days, it may cause huge loss as it interrupts subsequent steps especially in process industries. In this research, the importance of preventive maintenance strategy for steam boilers in Kuwaiti industries has been studied. Based on relative advantages and disadvantages, a proper strategy is proposed for better management and effective maintenance of boilers.
 
Top-cited authors
Mohammad Yeakub Ali
  • Universiti Teknologi Brunei
Asfana Banu
Mohammad Zoynal Abedin
  • Dhaka University of Engineering & Technology
Erry Yulian Triblas Adesta
  • International Islamic University Malaysia
A.N.M. Mominul Islam Mukut
  • Dhaka University of Engineering & Technology