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    Carbon emissions and overall sustainability assessment in eco-friendly machining of Monel-400 alloy
    (Elsevier, 2023) Ross, Nimel Sworna; Rai, Ritu; Ananth, M. B. J.; Srinivasan, D.; Ganesh, M.; Gupta, Munish Kumar; Korkmaz, Mehmet Erdi
    With increasing regulations about global warming, environmental pollution, and climate change, reducing carbon emissions from energy-intensive industrial activities routes to sustainable production. Because of its robust thermo-physical qualities at elevated temperatures, Monel 400 alloy is a renowned material for employment in modern aviation, medical tools, and prosthetic parts. Though, its structural stability imparts its low thermal conductivity that causes heat accumulation at the tool-workpiece contact during machining, resulting in tool cutting-edge damage. Many bio-based cutting fluids have been already tried to curtail heat generation and environmental footprints to progress overall machinability. In this endeavor, the effectiveness of dry, minimum quantity lubrication (MQL), cryogenic carbon dioxide (CO2) and Nano based MQL (N-MQL) are evaluated in terms of important sustainability indicator Carbon emission (CE). Multi-walled carbon Nano-tubes (MWCNT) in MQL oil limit the friction at the contact region which in turn reduces the power consumption. The highest CE value was found under a dry (0.0051 Kg-CO2) cutting environment and the lowest with N-MQL (0.0014 Kg-CO2). The sustainability assessment was done for CE with the help of Machine learning (ML) tech-niques like Decision tree (DT), Naive Bayes, Random Forest (RF), and Support Vector Machine (SVM). Finally, when the CE levels are discretized while considering industrial needs, SVM paired with the Synthetic Minority Over-sampling approach (SMOTE) demonstrated an accuracy of almost around 100%.
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    Development and potential use of MWCNT suspended in vegetable oil as a cutting fluid in machining of Monel 400
    (Elsevier, 2023) Ross, Nimel Sworna; Ganesh, M.; Ananth, M. Belsam Jeba; Kumar, M.; Rai, Ritu; Gupta, Munish Kumar; Korkmaz, Mehmet Erdi
    The heat dissipation problem that arises when machining difficult to cut materials can be mitigated by using nano-cutting fluids, which have a much higher thermal conductivity value than the basic lubricants. Since the heat carrying capacity of the Minimum Quantity Lubrication (MQL) system is significantly lower than that of other coolants, a number of nano-additives are used to increase its cooling effectiveness. Therefore, this study firstly focuses on the assessment of nano-cutting fluids and their significant efficacy in the machining operation of nickel-based alloys. Multi-walled carbon nanotube (MWCNT) suspended in vegetable oil is compared with distinct cooling environmental conditions namely, dry, MQL and cryogenic carbon dioxide (CO2). The novelty of this work is that the different volume fractions of 0.2 - 1 wt% of MWCNT were dispersed to study the contact angle, viscosity and thermal conductivity of the prepared molecular liquid and then, the potential of MWCNT suspended in vegetable oil is used to evaluate the outcomes of surface roughness (Ra), cutting temperature (CT) and tool wear (Vb) while machining Monel 400 alloy. The outcomes affirmed that employing nano MQL in machining operations resulted in a mean reduction of about 65% in the temperature evolved concerning no coolant condition. Additionally, the use of nanoparticles leads to an improved surface finish and abridged tool wear.
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    A State of the Art on Sustainable Metal Working Fluids in Machining Applications
    (World Scientific Publ Co Pte Ltd, 2024) Yurtkuran, Hakan; Guenay, Mustafa; Rai, Ritu
    Metalworking fluids (MWFs) play a crucial role in machining processes by lubricating and cooling cutting tools, reducing friction, and improving overall machining efficiency. These fluids can be classified into various types, including cutting oils, water-based fluids, and semi-synthetic or synthetic fluids. Cutting oils are often mineral-based, providing excellent lubrication in heavy-duty applications. Water-based fluids, on the other hand, are more environmentally friendly and commonly used in light to moderate machining operations. Semi-synthetic and synthetic fluids offer a balance between performance and eco-friendliness, incorporating additives to enhance their properties. Proper selection and management of MWFs are essential for optimizing tool life, surface finish, and overall productivity in metal machining applications. Research has shown that the cost of cutting fluid in machining constitutes 17% of the total production cost. In the same research, it was stated that the cutting tool cost was around 4%. This review provides an overview of the current advancements in sustainable MWFs within machining applications. It explores state-of-the-art technologies, formulations, and practices aimed at minimizing environmental impact while maintaining optimal performance in metalworking processes. The review encompasses eco-friendly additives, recycling methods, and emerging trends in the development of MWFs, emphasizing the importance of sustainable practices in the manufacturing industry.
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    Studies on newly developed hBN/graphene-based nano-fluids supported by cryogenic cooling conditions in improving the tribological performance of Ti6Al4V alloy
    (Elsevier, 2024) Korkmaz, Mehmet Erdi; Rai, Ritu; Demirsoz, Recep; Picak, Sezer; Vashishtha, Govind; Gunay, Mustafa
    Hexagonal Boron Nitride (hBN) is often referred to as a soft material due to its layered structure and properties that distinguish it from conventional hard materials like ceramics. The layered structure of hBN imparts lamellar lubrication characteristics and the weak van der Waals forces between adjacent layers allow for easy sliding, leading to low frictional resistance. The softness of hBN allows for ease of processing into various forms, facilitating its incorporation into lubricants, coatings, and composite materials. Therefore, the aim of this work is to enhance the lubricating capabilities of the nano-fluids and optimize the frictional behavior of Ti6Al4V alloy against tungsten carbide (WC) abrasive ball for potential biomedical applications, especially for combination of Ti6Al4V femoral stem and carbide femoral head. The newly formulated nano-fluids combine the unique properties of hBN and graphene to create a synergistic lubricating environment. The tribology and advanced characterization techniques were used to analyze the wear behavior of Ti6Al4V alloy surfaces. The results demonstrated that the applciaiton of cryogenically cooled lubricants with nanoparticles exhibited the lowest wear depth and friction forces, as a result of their increased viscosity.