Metallurgical and Materials Engineering (E-Journal)
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Distribution of heavy metals from tailings ponds and landfills into underground and surface waters
Get PDFHeavy metals contaminate underground and surface waters from illegally constructed industrial and municipal landfills. Numerous papers on the subject contain undeniable evidence, and they have determined heavy metal migration into nature by measuring concentrations in underground and surface waters near tailings ponds and landfills. Heavy metal measured values exceed the WHO limit quota. The characteristics of heavy metals and their negative impact on the environment and people's health have prompted a large number of investigations into this global problem. This paper provides an overview of the literature on the subject, with the goal of emphasizing the anthropogenic influence of heavy metal pollution as a critical issue, particularly in developing countries
Design Analysis And Improvement Of Multi-Operation Agri Robot With Renewable Energy Sources
Get PDFA hybrid-powered multi-operation agricultural robot integrating solar and wind energy is presented, capable of autonomous seeding, weeding, spraying, and harvesting. The modular system uses a 400 W solar array and a 200 W vertical-axis micro wind turbine with Li‑ion battery storage. Mechanical design employed structural optimization; control architecture integrates ROS‑based SLAM navigation and CNN-based weed detection. Simulations (MATLAB/Simulink, ANSYS, Gazebo‑ROS) and field trials (2-acre vegetable farm, 30 days) achieved energy autonomy, task accuracy between 85–96%, 11.2h/day runtime, and 35% cost savings compared to conventional methods. Improvements include panel dust-cleaning, AI‑enhanced perception, and energy enhancements. The design demonstrates viability and scalability of sustainable, low-cost agri‑robotics for small-/medium-scale farms
Endothermic solvent extraction of copper (II) with furfuryl thioalcohol from sulfate medium
Get PDFA simple solvent extraction method was developed to extract copper (II) from sulfate solution. The extraction of copper (II) with furfuryl thioalcohol was investigated. The effect of variables such as aqueous phase pH, furfuryl thioalcohol concentration, temperature, stripping reagents, and diluents was investigated. The extraction data revealed that using 15% (v/v) furfuryl thioalcohol with aqueous solution containing 0.5 mol L-1 Na2SO4, equilibrium pH 5.5, and phase ratio organic phase: aqueous phase (O:A) of 1:1 resulted in 98.20 percent extraction of copper (II) without nickel coextraction (II). Extraction isotherm results show that the extraction procedure is endothermic, with ΔH = 28.542 kJ mol-1 and ΔS = 41.740 J K-1 mol-1. Using 2.0 M H2SO4, copper loaded in organic phase was stripped at a rate greater than 99 percent
An investigation on dry sliding wear behavior of aluminum based metal matrix composites using grey relational analysis coupled with principle component analysis
Get PDF The current study reports on wear properties of aluminum 6061-T6 reinforced with titanium carbide and graphite hybrid metal matrix composite using principal component analysis based grey relational analysis. Experiments were carried out using Taguchi's L9 orthogonal array. The dry sliding wear properties of composite samples are evaluated using a Pin-on-Disc apparatus. The effects of wear parameter input variables such as load, sliding speed, and sliding distance on different output responses, namely wear rate, friction force, and coefficient of friction, were investigated in this work. Using grey relational analysis in conjunction with principal component analysis, three output responses from each experiment were normalized into a weighted grey relational grade. According to the analysis of variance, the most influential parameter is sliding velocity (45.51%), followed by load (26.75%) and sliding distance (2.94%), all of which contribute to the quality characteristics. Additional experiments have confirmed optimal results. Finally, a scanning electron microscopic analysis was performed to investigate the wear mechanism
Contribution to the Serbian coal ranking and fly ash characterization using Pb isotopic ratio
Get PDFThe Republic of Serbia generates the majority of its electricity at the thermal power plants (TE) Nikola Tesla, Kolubara, and Kostolac. Coal is extracted from the Kolubara basin, which produces approximately 70% of lignite (an average of 30 million tons per year), and the Kostolac basin, which produces 30% of lignite. Ash, fly ash, and slag are examples of coal combustion residues. Because of the high content of potentially hazardous elements such as As, Pb, Cd, and Cr, environmental pollution with ash and fly ash has been extensively researched. Stable isotopes of lead can be used to trace lead sources. It is possible to monitor the presence, transformation pathways, and environmental impact of Pb by determining its isotopic composition in coal and fly ash. For the first time, the isotopic composition of selected coal samples from the Kolubara and Kostolac mines, as well as fly ash from the Kolubara (A and B), Kostolac (A and B), and Nikola Tesla (TENT A3, A2, B2) thermal power plants, was investigated in this study. The obtained data for 206Pb/207Pb in coal serve as the foundation for ranking domestic coals, whereas the isotopic ratios 206Pb/207Pb and 208Pb/207Pb in fly ash can be used to monitor and control lead pollution from investigated sources
An overview on the microstructure and mechanical properties of sintered aluminum-based composites
Get PDFSintered composites have revolutionized as a thermal treatment to consolidate a wide range of engineering materials where the transition of powders takes place thermally in a thermodynamical equilibrium state with a decrease in free surface energy in materials owing to their specific capability. Sintering aids in providing effective bonding between the reinforced powder particles. However, the inadequate understanding of the sintering mechanism may limit the practical application of a few materials such as aluminum metal matrix composites. In addition to the rapid growth of various sintering related technologies, researchers need attention to highlight the structural barriers and forecast the emerging demands while dealing with such composites. A review report is made in this paper regarding the sintering mechanisms and sintering techniques. Common sintering techniques such as traditional, microwave assisted, hot pressing, hot isostatic sintering, and spark plasma sintering are identified and discussed here. As a result, the key challenges in sintering aluminium metal matrix composites that can affect sintering parameters are investigated. From the review, spark plasma is identified to attain densified and pore-free green composites and, microwave sintering is the best technique for achieving uniform microstructure in powder metallurgy samples
Eco-friendly Elderberry based sorbent for removing Pb2+ ions from aqueous solutions
Get PDFElderberry (Sambucus nigra) pith was modified with polyethyleneimine (PEI) in order to improve the adsorption properties. Characterization of both dried Sambucus nigra pith (DSNP) and amino modification of elderberry pith with branched PEI (PEI/DSNP) was performed by: Fourier-transform infrared spectroscopy (FTIR), optical microscopy, and porosity determination. The amine and ester number, as well as acid value, were determined on DSNP and PEI/DSNP samples using standard volumetric methods. The samples were used as adsorbents for Pb2+ ions from an aqueous solution in a batch system. The obtained results were fitted using suitable equilibrium isotherm and kinetic models. The maximum adsorption capacity for Pb2+ ions on DSNP and aminаted sample, obtained using Langmuir adsorption isotherm at 298 K, are 18.9 and 47.8 mg g-1, respectively. Based on the kinetic studies, the adsorption process follows the pseudo second-order model. Thermodynamic parameters showed that the adsorption process is endothermic and spontaneous. In general, the overall adsorption process was improved by modifying starting material with branched PEI modifier by introducing large numbers of amino functionalities having high affinity to cations
A study on Morphological and Mechanical Characterization of Al-4032/SiC/GP Hybrid Composites
Get PDFThe pattern of metal matrix composites can be enhanced by integrating the concept of hybrid metal matrix composite to produce newer engineering materials with improved properties. The morphological and mechanical characteristics of Al-4032/SiC/GP hybrid composites have been investigated. The aluminium alloy (Al-4032) based hybrid composites have been fabricated through the bottom pouring stir casting set up, by reinforcing the silicon carbide (SiC) and granite powder ceramic particles as the reinforcement material at various fraction levels i.e. 0, 3, 6, 9 weight% in equal proportion. The reinforcement particle size is up to 54μm. The microstructural characterization of the hybrid composite samples has been carried out using an optical microscope, SEM, and XRD. The study reveals that the reinforcement hybrid particles (SiC + GP) are almost uniformly distributed throughout the matrix phase. The mechanical properties (tensile strength, impact strength, and microhardness) of the hybrid composite samples have been obtained and found to be better than the unreinforced alloy.
Historical overview of refractory lining in the blast furnace
Get PDFThe majority of refractories used today are associated with the iron and steel industries. Typically, the refractory lining of a blast furnace consists of a combination of different refractory materials chosen for different portions of the furnace, as well as distinct process conditions and temperature ranges. Knowledge and requirements for the iron manufacturing system in conjunction with the physical, mechanical, and chemical qualities of the proposed refractories determine the choice of refractory combination. Inadequate understanding of the aforementioned components frequently results in refractory failure, which then becomes a difficult problem to tackle. A blast furnace's refractory liner typically fails owing to any number or combination of these variables. To facilitate comprehension, we will explain the types of refractory lining required in a blast furnace by region, as well as the observed trend in refractory lining patterns over the past few decades
Effect of film thickness on the structural and tribo-mechanical properties of reactive sputtered molybdenum nitride thin films
Get PDFThe current study aims to examine the impact of nitrogen content and film thickness on the structural and tribo-mechanical characteristics of reactive sputtered MoN thin films. Molybdenum nitride thin films with thicknesses ranging from 0.2 to 1.25 m have been applied to steel and silicon substrates for this purpose, with various amounts of controlled atmosphere (Ar+N2). Then, the films are characterized using XRD (X-ray diffraction), EDX (energy dispersive X-ray analysis), SEM (scanning electron microscopy), FTIR (Fourier-transform infrared spectroscopy), and nanoindentation. The residual stress was measured using the Stoney formula. Results show that a high compressive residual stress of -5.7 GPa is present in the film with a 0.3 μm thickness and gradually decreases with increasing film thickness. Above 1 µm of film thickness, there is no change in the density of the MoN films. Also, the coating hardness and Young’s modulus vary between 9.5 and 35 GPa, and 266 and 320 GPa, respectively, depending on nitrogen content and film thickness. Lastly, the friction of the MoN thin films is estimated to be around 0.55, which proves that the oxide is being slowly removed