Applied Mechanics and Materials Vol. 920

Abstract: Nickel is used as a raw material for Nickel Manganese Cobalt (NMC) batteries as a compound of Nickel Sulphate Hexahydrate (NiSO₄.6H₂O). This study used nickel laterite as ore. A hydrometallurgical process carries out Ferronickel to extract nickel concentrate. The first step is leaching using 2M H₂SO₄ solution for 6 hours with a stirring speed of 200 rpm at 90°C. The leached solution was then neutralized using a neutralizing agent MgO 5% w/w until it reached a pH of 3.5. The neutralized filtrate was then filtered to separate the filtrate and the residue. The neutralization process produces magnesium sulfate salt (MgSO₄), which is an impurity. Next, the cooling temperature method is used to precipitate MgSO₄ crystals. In this study, the variation of the MgSO₄ cooling temperature used was -5, 0, and 5 °C. Subsequently, crystallization was carried out to produce NiSO4.6H2O. The highest nickel recovery (59.61%) can be achieved using a cooling temperature of -5 °C. Also, by using -5 °C of cooling temperature, the nickel content of crystal product is 2.75%. The crystallization product still contains other compounds, such as MgSO₄, FeSO₄, and CoSO₄.

Abstract: The increasing demand for electric vehicles affects the high demand for nickel-based batteries, including Nickel Manganese Cobalt (NMC) batteries. Generally, NMC is processed from high-quality ore (sulfide ore) to produce nickel (II) sulfate hexahydrate or NiSO₄.6H₂O. But sulfide ore face scarcity due to a long history of mining and exploitation. Thus, laterite-type nickel ore can be an alternative to nickel resources. This study aims to produce mixed sulfate precipitates from a ferronickel leaching solution that can be utilized further to produce NiSO₄.6H₂O. Also, this research will study the pH effect of the precipitation process on the product's elemental composition, recovery, and compounds formed. The precipitation process was conducted using 5% MgO (weight basis) with a pH range of 2.5 to 6.5 with one increment. The mixed sulfate precipitates were characterized using AAS, EDX, and XRD. When using a pH of 3.5, a nickel concentration of 1473.00 ppm, nickel recovery of 23.02%, and Nickel grade of 3.18% could be obtained. As a result, the phase of NiSO₄.6H₂O was formed. Also, the other phases were formed after precipitation, such as CoSO₄, FeSO₄, and MgSO₄.

Abstract: Although Fused Filament Fabrication (FFF) technology has gained popularity and is used extensively since the last decade, the low mechanical properties of the resulting product have been recognized as the major limitation of this technique. The anisotropic nature of the printed products due to the layered structure and many cavities that are present inside the printed parts are among the main causes of this problem. In this study, the powder addition reinforcement (PAR) method had been developed by introducing reinforcing powder into the polylactic acid (PLA) as the base material during the printing process so that nozzle clogging can be avoided and powders can be placed between the layers. In this work, iron oxide nanoparticles (Fe₂O₃) were used as a reinforcing powder. The addition of this powder was carried out by using two methods, namely brushing and compressed air-assisted techniques. The results showed that the compressed-air assisted technique demonstrated better results in terms of mechanical properties. In this case, the tensile strength of the composite with the compressed-air assisted technique was higher by 28.95% than that of the PLA and by 5.53% - 25.2% than that of the brushing method. Finally, this study showed that the compressed air-assisted method is the potential to be developed in the future as a powder addition reinforcement technique in the FFF process.

Abstract: Fused Filament Fabrication (FFF) continues to experience improvements in terms of its flexibility and functionality, therefore it attracts public attention to use this technology. Multi-Material Additive Manufacturing (MMAM) is an approach in the FFF technology that allows the manufacturing of 3D-printed products composed of two or more materials in a single printing process. MMAM enables the user to apply various configurations to obtain a 3D-printed material with adjustable properties. This study aims to determine the effect of core material on the Shore hardness of the FFF printed parts with the MMAM approach. There were two types of materials combined with the MMAM approach in this work, namely polylactic-acid (PLA) and thermoplastic elastomer (TPE). The Shore hardness test was conducted according to the ASTM D2240-15 standard. The results showed that the thickness of the core material inserted into the printed material had a significant effect on the hardness value of printed multi-material parts. In addition, the hardness value was highly dependent on the modulus of elasticity of the material. Therefore, the hardness value changed following the proportion of the printed material.

Abstract: Fused filament fabrication (FFF) has nowadays become a popular 3-dimensional (3D) printing technique for the fabrication of polymeric components with customized and complex-shape design, including biomedical implants. However, the use of this technique is often constrained by the limited number of polymeric materials that can be printed to form the final product. Despite excellent wear resistance and widely used as the acetabular component of a joint prosthesis, ultra-high molecular weight polyethylene (UHMWPE) is among such the rarely-found filament material in the market. In this research, preliminary work to fabricate UHMWPE filament for the FFF processing is carried out by using extrusion. The influences of extrusion temperature, addition of polyethylene glycol (PEG), and rotational speed of the extruder’s screw on the physical, chemical, and mechanical properties of the extruded UHMWPE filament were determined. The result demonstrated no change in the chemical compositions of the filament due to the processing parameters applied, as noted from the FTIR spectra. The result of the tensile test showed that the highest tensile strength of UHMWPE filaments could reach 23.5 MPa.

Abstract: Digital light processing (DLP) technology has been developed based on stereolithography (SLA) 3D-printing principle. The biodegradable and low-cost polylactic-acid (PLA) has so far been used as polymeric material for photopolymer resin in SLA and DLP. To achieve functional SLA-processed product, the properties of such PLA has been improved, with the aim to make it flame retardant, less viscous, and having light transmittance characteristics. In this study, the liquid raw PLA photopolymer was changed by adding different contents of Ammonium Phosphate (APP), melamine cyanurate (MCA), Aluminum Tri-hydroxide (Al₂O₃) and Nano-silicon dioxide (SiO₂) additives. The solid PLA nanocomposite specimens were printed by using DLP device according to the standard geometry for burning test UL-94 to evaluate its flame-retardant property. In addition, the printing product and residue after burning test was analyzed for their morphological characteristic by using SEM. The results showed that the low weight fraction of MCA showed excellent performance. PLA/MCA successfully kept green body form until the sintering temperature of stainless steel was achieved. It can become a reference for application DLP 3D printing products in the casting and sintering process.

Abstract: Storage is an important aspect of any business. All businesses must store goods and materials safely, especially warehouses, factories, shops, food, agricultural, and construction businesses. Leaving materials exposed reduces their overall quality; hence, certain structures are used to safely retain the materials for further use. These are called storage structures. A silo is a commonly used storage structure for the storage of bulk materials such as grain and cement. This paper deals with the design of a steel silo for the storage of pozzolana cement. A storage silo is essentially made up of a cylinder-shaped wall and a hopper bottom. Steel Silos are gaining more popularity in terms of cement storage usage. A 150-ton capacity steel silo has been designed for a seismic zone-2 [1] location in Madurai, Tamil Nadu, India (therefore omitting the inclusion of seismic loads). The preliminary design of the silo structure is carried out with the help of Indian Standard code books. Indian Standard code books such as IS 9178-Parts 1,2 & 3 (1979) were used for the basic design. Other necessary code books were used for load calculations. The plan and elevation of the Silo have been drafted by using AutoCAD. The designed Silo is analysed using STAAD Pro. The pile foundation of the Steel Silo has also been designed and analysed using STAAD Foundation.

Abstract: Due to the recent developments in design optimization techniques and advanced construction technologies, uses of castellated beams have become very popular. Castellated beams because of their high strength to weight ratio and low maintenance and painting cost have effectively replaced built-up girders in light to medium constructions for medium to long spans. Longitudinal cuts in the form of openings along the web of castellated beams also results in stronger and stiffer beams than their parent beams without any increase in the self-weight. In this study, attempts are made to compare the behavior of castellated beams with their parent beams. Studies on effect of different web openings on deflection are carried out using finite element analysis.

Abstract: The main objective of this research is to identify the variables that affect the level of service (Los) of pedestrians at intersections both (signalized and unsignalized) in shivamogga city. Based on the experiences of the pedestrians at the individual in intersections. A walker’s questionnaire survey was done to gather level of service of pedestrians in terms of protection, comfort, and convenience for every crossing at signalized & unsignalized intersections. Additionally, a video graphic method was employed to scan each crosswalk at the chosen three signalized and two unsignalized intersections. Pedestrian crossing time, pedestrian waiting time, pedestrian holding area, roadway width, and crosswalk surface condition were the key variables taken into account for the construction of the model. For each crossing, a considerable number of pedestrian ratings were collected, these ratings were used as the dependent variables in the analysis. In order to estimate the pedestrian level of service for each intersection's crosswalk, a stepwise multiple linear regression analysis utilizing SPSS software is used to construct a pedestrian Los model.