International Journal of Integrated Engineering
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A Hybrid Analytical-Numerical Model of Heat Generation and Distribution in Friction Stir Welded AA2024 Butt Joints
Get PDFBeing a solid-state process, friction stir welding (FSW) is considered a candidate technique for welding critically-microstructure-sensitive materials such as heat-treatable aluminum alloys. A hybrid computational model that employs both analytical and numerical approaches was used to estimate the amount of heat generated in the FSW of AA2024-T4 butt-welded sheets and how it is distributed as a function of time using a 3D transient heat transfer finite element analysis (FEA). Experimental procedures were used to validate the heat distribution in the welded butt joints using candidate rotational and travel speeds from the numerical model. The model outcomes show that rotational speed less than 600 rpm gives insufficient heat input when the optimum travel speed is 25 mm/min while higher rpm would cause overheating and flash formation. Structural and mechanical joint characterizations were performed to ensure the validity of the optimized process parameters. The model recommended parameters give the defect-free butt joints with the best efficiency in terms of ultimate strength. The Vickers hardness profile (W-shaped) for the welds’ cross-sections shows that 600 rpm gives the highest values in all different weld zones compared to that welded at 400 and 800 rpm
Combination of Oven and Microwave-assisted Drying Technique for Production of Ready-to-Eat Dried Rice
Get PDFA combination of oven and microwave was introduced with the purpose of preparing well-balanced dried ready-to-eat dried rice samples. The parameter condition was investigated (oven temperature; 70 and 90 °C, time; 70, 130 and 180 min, microwave power; 450 and 750 W and time; 1, 2, 3, 4 and 5 min). From the study, increasing in moisture content and rehydration capability was obtained when the drying conditions were increased. However, the color product was changing as the color difference was improved whereby the samples with lower water activity have lower microorganism growth (0.4-0.5 wa). The nutrient obtained were in the range of 55.5 - 65.9% for carbohydrate, 6.4 - 9.3% for protein, 65.9 - 17.3% for fat and 3.4 - 3.5 for ash content, respectively. It can be concluded that the use of oven and microwave in this study is acceptable for preparing ready-to-eat dried rice
High Temperature Corrosion Study on NiCr Coated Low Alloy and Mild Steel
Get PDFCyclic hot corrosion behaviour of bare and D-gun sprayed NiCr coated low alloy and mild steel sample having dissimilar coating thicknesses viz. 0.2-0.25 mm and 0.25-0.30 mm have been studied in molten salt environment mixture of Na2SO4 - 25wt. % NaCl at temperature of 750?C. Corrosion kinetics were analysed and parabolic rate constants (Kp) for both bare and coated sample were calculated and observed that 0.2-0.25 mm thick NiCr coated specimen showed better resistance against high temperature corrosion for both materials. SEM/EDX analysis was carried out to examine scale formed on the bare and coated Sample after hot corrosion
Investigation of Functional Ageing of GNP/Ag Conductive Ink under Torsional Conditions
Get PDFThis study evaluated the ageing effects after enduring a cyclic torsional test on electrically high thermal Graphene Nanoplates (GNP)/Ag conductive ink. The Graphene Nanoplates (GNP) hybrid formulation contained silver flake (Ag) as an additional filler, 1-butanol and terpineol as organic solvents for the paste, and ethanol as a chemical solvent for the powder GNP hybrid synthesis. An in-house torsional cyclic test rig acted as an experimental apparatus to hold cyclic torsional tests in measuring the resistivity value of GNP/Ag conductive ink. The sample endured 1000, 2000, and 4000 cycles of repetitive cyclic torsion. The sample was left unattended in a controlled environment for ageing process observation in 15 weeks. Resistivity values for both tests were obtained by using a two-point probe multimeter. Data from the cyclic torsional test showed an increase in average resistivity as the cycles prolonged until 4000 cycles. The outcome of these experiments proved that Graphene Nanoplates (GNP)/Ag conductive ink manages to withstand material deformation and remain electrically stable after experiencing cyclic twisting and the ageing process. The recorded SEM images of the ink layer microstructure surface showed a direct correlation with the obtained sheet resistivity data. The samples that produced high sheet resistivity showed the presence of microcracks and defects on the ink layer The results of this study imply that repeated twisting in a thin film may lead to different mechanical and material modifications, thereby influencing its electrical and mechanical properties, which is vital to developing more reliable and stable stretchable electronics. Additional research on various twisting angles and ink compositions is recommended to have a more profound understanding of the characteristics and features of GNP/Ag conductive ink
The Effect of Compressive Stress on Ultrasonic Pulse Velocity in Concrete for Compressive Strength Prediction
Get PDFUltrasonic pulse velocity (UPV) has been a popular non-destructive testing method for prediction of concrete strength. This leads to development of two major types of concrete compressive strength prediction models using measured UPV values, namely the exponential function and the power function. A simpler exponential function, recognised as one of the earliest, has proven to be more accurate in predicting the concrete compressive strength. From this study, it was observed that measured UPV increases with the increase in stress-to-strength ratio of up to 0.25, and the measured UPV decreases thereafter. The increase in UPV will lead to overestimation of concrete compressive strength by up to 15%. However, if ⅓ of compressive strength is considered as service stress, then the overestimation of concrete compressive strength will be lower at about 8%, and may even register a slight underestimation occasionally; due to the decrease in measured UPV values beyond stress-to-strength ratio of 0.25
Mechanical Properties of Thulium-doped Bismuth Borotellurite Glass via Nanoindentation for Lead-Free Radiation Shielding Application
Get PDFCommercially, lead-based glasses are used in industry as transparent radiation shielding material due to their durability. However, lead toxicity could cause detrimental health issues to humans. Thus, in this study, a new composition of thulium-doped bismuth borotellurite glass was fabricated via melt-and-quench technique. The effect of bismuth oxide (Bi2O3) on the physical, structural, and mechanical properties of the glass was investigated. Glass with 0.25 mol% of Bi2O3 has the highest density. However, the oxygen packing density (OPD) of glass with 0.15 mol% of Bi2O3 is higher than 0.25 mol% of Bi2O3. This is due to a high number of non-bridging oxygen (NBOs) in 0.25 mol% of Bi2O3 glass structure. The bonds that are present in the glass structure were verified by Fourier Transform Infrared Spectroscopy (FTIR) analysis. Then, the mechanical properties were investigated by nanoindentation test with Berkovich indenter. Comparing the mechanical properties of indented glass samples, 0.15Bi glass projected the best mechanical durability since it provides the highest hardness and reduced elastic modulus value. Also, the low plastic work and optimal elastic work make 0.15Bi glass resilient to stress. Thus, the 0.15Bi glass is deemed as the best glass sample for high mechanical strength radiation shielding glass. This lead-free radiation shielding glass does not pose harmful effects to humans
Simulation and Design of Modified Adaptive-based Maximum Power Point Tracking Methods for Photovoltaic Systems
Get PDFThe quality of the supplied electrical energy is becoming increasingly stringent as the use of energy grows. As traditional energy sources grow depleted and the cost of electricity rises, photovoltaic energy emerges as a possible option. A growing number of people are turning to photovoltaic (PV) generation as a renewable energy source due to its many benefits, including low maintenance and quiet operation. This research compares the most widely used MPPT algorithms which are the Adaptive fixed duty ratio method (AFDR) and the Adaptive variable duty ratio method (AVDR). In this paper the simulation and analytical analysis for the two MPPT techniques of AFDR and AVDR for the PV System under three methodologies such as irradiation, duty cycle variations of the converter, and load variations. From the results, it was found that AVDR increased the PV output power and the AVDR method has proved that it has fast transient convergence with a better steady-state tracking efficiency
Optimal Operation of Autonomous Energy System Based on Multi-objective Approach
Get PDFThe present investigation on the optimal scheduling of the autonomous energy system (AES) considers technical and economic indices. Demand management has been proposed to enhance the technical and economic indices during operation. The implementation of load demand management is contingent upon bid prices offered to consumers for the purpose of reducing demand during emergency situations. The economic and technical objectives are based on multi-objective modeling, which includes minimizing operational costs and improving voltage indices. The optimization of the multi-objective problem is executed through the utilization of the Particle swarm optimization (PSO) algorithm. The desired optimal solution within the non-dominated solutions is obtained by employing the fuzzy max-min method. Ultimately, to demonstrate the efficacy and validation of the proposed strategy, the aforementioned strategy is implemented in two case studies on the 33 bus IEEE test system
Enhancing Fastener Standardization for Disassembly: A Path to Sustainable Laptop Design
Get PDFThis project aims to design a laptop for easy of disassembly, thereby reducing disassembly time. The challenges associated with product disassembly include the complexity of replacing worn-out components, managing various types of fasteners, and finding solutions for end-of-life products. This paper focuses on the design for disassembly of laptops by standardizing fasteners to minimize disassembly time. A modified design is proposed to decrease the disassembly time of the laptop compared to the reference design. The laptop components and fasteners are designed using Autodesk Inventor, and the disassembly time is calculated accordingly. The comparison between the new design and the reference design reveals significant improvements in disassembly time for both the laptop screen and keyboard. Specifically, the disassembly time is reduced by a factor of 4 for the laptop screen and 4.5 for the keyboard. Furthermore, the number of required disassembly tools is reduced from three different screwdrivers to just one. The primary objective of the new laptop design is to ensure easy disassembly and reassembly. By making product components easily accessible for repair, replacement, recycling, and reuse, this design not only saves time and resources for manufacturing and recycling companies but also reduces labor costs. It enhances customer satisfaction and minimizes the time and effort required for quick disassembly during product repair and refurbishment. In conclusion, Design for Disassembly is an effective approach for creating sustainable products that can be easily disassembled, facilitating simpler maintenance, repair, recovery, and reuse of components and materials
Impact of a Stretching Program on Musculoskeletal Discomfort in Online Motorcycle Taxi Drivers: A Pre-Post Intervention Study
Get PDFThe prevalence of musculoskeletal discomfort is a current issue for online motorcycle taxi drivers. Any work must cause muscle complaints. Therefore, this article will answer the problem regarding the impact of musculoskeletal discomfort before and after the stretching program. Statistical tests are needed, including chi-square and Wilcoxon and brainstorming the specifications of the stretching program movement to 70 respondents. It was stated that there was a relationship between the NBM instrument and the respondent\u27s characteristics and the level of significant differences before and after the stretching program with the specification of 8 stretching movements that could be carried out at 10.00 WIB and 15.00 WIB with an estimated time of up to 24 minutes. It is hoped that this can be a development in reducing musculoskeletal discomfort complaints that are sustainable