Search

Abstract The surface morphology and roughness of a workpiece are crucial parameters in grinding processes. Accurate prediction of these parameters is essential for maintaining the workpiece’s surface integrity. However, the randomness of abrasive grain shapes and workpiece surface formation behaviors poses significant challenges, and accuracy in current physical mechanism-based predictive models is needed. To address this problem, by using the random plane method and accounting for the random morphology and distribution of abrasive grains, this paper proposes a novel method to model CBN grinding wheels and predict workpiece surface roughness. First, a kinematic model of a single abrasive grain is developed to accurately capture the three-dimensional morphology of the grinding wheel. Next, by formulating an elastic deformation and formation model of the workpiece surface based on Hertz theory, the variation in grinding arc length at different grinding depths is revealed. Subsequently, a predictive model for the surface morphology of the workpiece ground by a single abrasive grain is devised. This model integrates the normal distribution model of abrasive grain size and the spatial distribution model of abrasive grain positions, to elucidate how the circumferential and axial distribution of abrasive grains influences workpiece surface formation. Lastly, by integrating the dynamic effective abrasive grain model, a predictive model for the surface morphology and roughness of the grinding wheel is established. To examine the impact of changing the grit size of the grinding wheel and grinding depth on workpiece surface roughness, and to validate the accuracy of the model, experiments are conducted. Results indicate that the predicted three-dimensional morphology of the grinding wheel and workpiece surfaces closely matches the actual grinding wheel and ground workpiece surfaces, with surface roughness prediction deviations as small as 2.3%.

Abstract Minimum quantity Lubrication (MQL) is a sustainable lubrication system that is famous in many machining systems. It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes. The MQL system is affirmed to exhibit an excellent machining performance, and it is highly economical. The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability, compared to pure oil-based MQL system. Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids. This work presents an experimental study on the tribological performance of SiO2 nanofluid during grinding of Si3N4 ceramic. The effect different grinding modes and lubrication systems during the grinding operation was also analyzed. Different concentrations of the SiO2 nanofluid was manufactured using canola, corn and sunflower oils. The quantitative evaluation of the grinding process was done based on the amount of grinding forces, specific grinding energy, frictional coefficient, and surface integrity. It was found that the canola oil exhibits optimal lubrication performance compared to corn oil, sunflower oil, and traditional lubrication systems. Additionally, the introduction of ultrasonic vibrations with the SiO2 nanofluid in MQL system was found to reduce the specific grinding energy, normal grinding forces, tangential grinding forces, and surface roughness by 65%, 57%, 65%, and 18% respectively. Finally, regression analysis was used to obtain an optimum parameter combinations. The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.

The microstructure, homogeneity, and tribo-corrosion behavior of microwave-developed Nickel as well as titanium dioxide SS-304 cladding surfaces are the primary emphasis of this research. The study includes assessing the hardness enhancement from Ni and TiO2 particles in the cladding surface. The investigation additionally evaluates cladding surface wear rates, friction coefficients, and resistance to corrosion under tribological conditions. The microstructure, homogeneity, and tribo-corrosion behavior of SS-304 cladding surface with Ni and TiO2 developed by microwave cladding energy were investigated in this study. The microstructure was being examined to validate the uniformly homogeneous dispersion of Ni and TiO2 particles, and XRD was employed to determine cladding surface phases. The hardness of the cladding surface was evaluated, and a pin-on-disk tribometer has assessed the wear behavior. Tribo-corrosion was tested in 3.5-percent NaCl solution. To enhance cladding's efficiency, microwave hybrid heating (MHH) utilising charcoal as a susceptor has been employed. Findings exhibited that the microstructure analysis showed that the cladding surface had a uniform distribution of Ni and TiO2 particles and a compact and homogeneous microstructure. The hardness of the cladding surface was significantly improved by about 37.68% due to the incorporation of Ni and 10% TiO2 particles. The FeNi3, NiSi2, Ni3C, NiC, Ni2Si, FeNi, and TiO2 phases were seen by XRD on the cladding surface. The behavior of the cladding surface under tribological conditions was also evaluated using a pin-on-disk tribometer. The outcomes have exhibited that the Ni and 10% TiO2 cladding surface exhibited decreased wear rates and friction coefficients compared to the uncoated SS-304 substrate. Moreover, the tribo-corrosion behavior of the cladding surface was evaluated in a 3.5% NaCl solution. The wear rate and coefficient of friction of Ni and 10% TiO2 cladding surfaces were measured to be 0.00412 mm3/m and 0.297, respectively. The results indicated that the Ni and TiO2 cladding surface had enhanced corrosion resistance compared to the uncoated SS-304 substrate.

Inadequate research regarding how material characteristics affect vital yield parameters in EDM, particularly for aluminium, brass, and Inconel 617. An limited study has examined how EDM process parameters like peak current (Ip), gap voltage, and pulse on time (Ton) affect recast layer thickness, tool wear rate, surface roughness, crack density, globule formation, material removal rate, and crater formation. The interaction between thermal conductivity, microcracks, and recast layers in EDM is uncertain. Material characteristics' implications on XRD patterns and globule formation during EDM machining were not extensively investigated. EDM process parameters and their impacts on response variables such tool wear rate (TWR), material removal rate (MRR), surface roughness, and globule formation for diverse materials have received minimal analysis. In addition, non-ferrous workpiece materials are integral to the electrical discharge machining process. This study delves into how the physical properties of materials influence key yield parameters, including tool wear rate, surface roughness, crack density, globules, material removal rate, and crater formation. The investigation covers Inconel 617, brass, and aluminum, revealing peak current (Ip) as the most influential factor for highly thermally conductive materials when compared to gap voltage and pulse on time (Ton). Notably, Inconel 617 exhibits longer cracks, while aluminum displays smaller ones, and deeper cracks are found on the surface of aluminum, contrasting with the broader craters observed on Inconel 617. Recast layer thickness varies, ranging from 8.3 μm for brass to 13.8 μm for aluminum. The study validates response values extensively against experimental data and highlights brass's superior surface finish. It further uncovers that plasma-generated craters are predominantly semispherical, with the plasma's diameter expanding faster than the crater's size. Sub-surface re-solidification emerges as a source of stress and micro-cracks, which diminish material's fatigue strength. Notably, aluminum exhibits a greater number of elegant microcracks on the machined surface, while brass and Inconel 617 have fewer. Recast layer thickness measurements indicate approximately 13.8 μm for aluminum, 8.3 μm for brass, and 9 μm for Inconel 617. Additionally, the thermal erosion process enhances the microhardness of the machining zone's subsurface due to the formation of oxides and carbides and the re-solidification of particles. Different material characteristics are revealed through X-ray diffraction (XRD) patterns, while globules, small and spherical, weakly adhere to the machining zone's subsurface. In particular, aluminum machined surfaces feature fewer globules, while brass surfaces exhibit a higher quantity, attributed to their varying thermal conductivity.

Inconel 718 finds extensive applications in the aviation and aerospace industries, particularly in the manufacturing of jet engines and high-speed airframe components like fasteners, bolts, buckets, instrumentation parts, wheels, and spacers. It is also utilised in the production of cryogenic tankage and gas turbine blades. The present study focuses on investigating the machining performance of graphene nanosheets on Inconel 718. Various aspects of Inconel 718's machinability through electrical discharge machining (EDM) have been examined, including material removal rate (MRR), surface roughness, surface morphology, tool rear Rate (TWR), residual stresses on the machined surface, Vickers hardness, and recast layer thickness. The investigation reveals a significant impact of process parameters on these machining characteristics. The effects of graphene nanosheets have been observed using several analytical instruments such as field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), particle size analyzer, and X-ray diffraction (XRD). Furthermore, optimization of the response data with respect to input parameters has been performed in this study. TEM analysis is used to determine the size of individual debris particles in deionised water and mixed graphene nanosheet dielectric mediums. To verify that the debris particles are the same as the parent material, energy dispersive X-ray spectroscopy (EDX) is used. To determine the compounds and crystal structures present in the base metal and machined surfaces, XRD analysis is used. A high-resolution X-ray diffractometer (HRXRD) is used to measure the residual stresses on the machined surface. EDX composition testing is used to analyze surface modification. Due to the rapid heating and quenching that takes place in the dielectric medium, the machined surface becomes harder. Deposited materials, microholes, and surface textures can all be observed through FESEM microstructure observation. Comparing conventional EDM to nanosheets mixed dielectric, the thickness of the recast layer is reduced. To recapitulate, the study explores how various machining parameters and dielectric mediums affect EDM processes. It examines debris particle size, compound formation, residual stresses, surface modification, hardness, microstructure, and recast layer thickness. The addition of graphene nanosheets to the dielectric medium produces promising results, reducing the thickness of the recast layer and improving surface quality. The results offer suggestions for improving Inconel 718 material surface properties and EDM machining effectiveness.

The rotavator blade, a part of an agricultural equipment rotavator, is used for the soil bed preparation. These blades have direct interaction with soil in agricultural land. Bad, rocky, gravel, sandy, and high rough-hard texture of soil are the main factor to damage the surface of the rotavator blade and a high wear rate is observed. This causes to decrease in the overall life of a rotavator blade. It also changes the geometry of the rotavator blade after a few operations, and that all effects the performance capability of this blade. Hence HVOF (High-velocity oxy-fuel) is used to modify the surface that improved wear resistance of the rotavator blade's surface. Feedstock powder used for the coating is WC–10%Co–4%Cr with Ni–20%Cr as a bond coat on 30MNCRB5 steel substrate (Rotavator blade's material). Six samples are prepared to test it on the Pin-On-Disc wear testing apparatus to determine the wear rate, weight loss, cumulative volume loss and linear wear rate, three bare 30MNCRB5 steel and three WC–10%Co–4%Cr coated samples are prepared with 8 mm diameter and 30 mm length in a cylindrical pin shape. Coated samples are characterized using the XRD (X-ray diffraction), SEM (Scanning electron microscope) with EDAX (Energy-dispersive spectroscopy), and X-ray mapping techniques. Worn out surfaces of bare 30MNCRB5 steel and WC–10%Co–4%Cr coated samples are investigated using the SEM (Scanning electron microscope) to study the microstructure of worn surface that helped out to identify the wear behavior. The HVOF (High-velocity oxy-fuel) spray coating drastically improved the surface to defend it from wear, and very less weight loss was seen in the WC–10%Co–4%Cr coated samples as compared to bare 30MNCRB5 steel material. Weight loss determined by the bare (30MNCRB5) material at 40N, 50N, 60N loads are 2.996 × 10−3 Kgm, 3.003 × 10−3 Kgm, 3.123 × 10−3 Kgm, and coated (WC–10%Co–4%Cr) sample at 40N, 50N, 60N loads are 0.006 × 10−3 Kgm, 0.030 × 10−3 Kgm, 0.038 × 10−3 Kgm respectively.

Abstract Micro-grinding with a spherical grinding head has been deemed an indispensable method in high-risk surgeries, such as neurosurgery and spine surgery, where bone grinding has long been plagued by the technical bottleneck of mechanical stress-induced crack damage. In response to this challenge, the ultrasound-assisted biological bone micro-grinding novel process with a spherical grinding head has been proposed by researchers. Force modeling is a prerequisite for process parameter determination in orthopedic surgery, and the difficulty in establishing and accurately predicting bone micro-grinding force prediction models is due to the geometric distribution of abrasive grains and the dynamic changes in geometry and kinematics during the cutting process. In addressing these critical needs and technical problems, the shape and protrusion heights of the wear particle of the spherical grinding head were first studied, and the gradual rule of the contact arc length under the action of high-speed rotating ultrasonic vibration was proposed. Second, the mathematical model of the maximum thickness of undeformed chips under ultrasonic vibration of the spherical grinding head was established. Results showed that ultrasonic vibration can reduce the maximum thickness of undeformed chips and increase the range of ductile and bone meal removals, revealing the mechanism of reducing grinding force. Further, the dynamic grinding behavior of different layers of abrasive particles under different instantaneous interaction states was studied. Finally, a prediction model of micro-grinding force was established in accordance with the relationship between grinding force and cutting depth, revealing the mechanism of micro-grinding force transfer under ultrasonic vibration. The theoretical model’s average deviations are 10.37% in x-axis direction, 6.85% in y-axis direction, and 7.81% in z-axis direction compared with the experimental results. This study provides theoretical guidance and technical support for clinical bone micro-grinding.

As advancements in sustainable material science continue, kenaf fiber and polylactic acid (KF/PLA) composites have emerged as promising eco-friendly alternatives. The current research article has focused on improving the physical strength of these KF/PLA composites. Methodologies like Taguchi's and Grey Relational Analysis (GRA) have been employed to identify the most effective ways to enhance the chemical treatment process. The composites were manufactured using an injection molding technique while essential variables were modified. These variables comprised the choice of chemical treatments (sodium hydroxide, potassium hydroxide, or sodium acetate), the concentration of these chemicals (1%, 2%, or 3% w/v), and the duration of treatment (2, 4, or 6 h). These modifications led to the production of diverse KF/PLA composite variants. The physical strength of these modified composites was evaluated using various methods, focusing on their tensile strength, tensile modulus, elongation under tension, flexural strength, flexural modulus, deformability under bending, and impact resistance. A Scanning Electron Microscope (SEM) was utilized to observe the treated and tested samples in detail. The optimal values identified through GRA and mean plots were same for the composite. Improved mechanical properties of KF/PLA were observed when the optimal conditions of A1-B2-C2 (NaOH, 2%, and 4 h) were applied. Although, the morphology of the PLA matrix-based bio composites reinforced with kenaf fiber with different surface-treatments was recorded using AFM analysis in order to further reveal the surface roughness of fibers upon surface modification and dispersion.

Nowadays, Fiber-reinforced Polymer Composites (FRPCs) are extensively utilized due to their remarkable properties such as high stiffness, excellent strength to weight ratio, resistance to wear, corrosion etc. Earlier, the FRPCs are prepared through synthetic fibers in order to attain high strength in conjunction with high elastic modulus. However, with the increasing economic and environmental factors regarding the accumulation of plastic waste, the development of natural and hybrid (combination of any two) fibers were started. The mechanical properties of FRPCs are largely determined by the way loads are transferred between the matrix and fibers, or by the strength of the bond between the fiber-matrix interfaces. Additionally, these factors play a significant role in determining the overall performance of FRPCs. Therefore, this review discusses the recent advancements in enhancing the interaction between fiber and matrix by means of chemical treatment and the inclusion of nanoparticles. The resulting mechanical performance of the end composites and their intended applications are also presented. Few targeted application areas of FRPCs such as aerospace, automobile, mechanical and biomedical implants were discussed in detail.

Aluminum composite materials have gained immense popularity in the construction and aerospace industries as these materials are lightweight, durable, and exhibit a high strength-to-weight ratio. The present study aims to develop dissimilar AA2024 and AA2014-based composite materials using nano-TiO2 reinforcement particles via Friction Stir Processing (FSP) techniques. The FSP technique is a solid-state processing method that is used to modify the properties of metal alloys without altering their chemical composition. The samples were prepared by placing a nano-TiO2over AA2024 and AA2014 aluminum alloys sheet and subjected to FSP process parameters. The microstructure, hardness, and tensile properties of the composite samples were assessed using scanning electron microscopy (SEM), Vickers hardness tester, and tensile testing machine respectively. The results showed that the FSP technique led to the formation of a homogeneous and fine-grained microstructure in the composite samples. The nano-TiO2 reinforcement also provided additional strengthening to the AA2024 and AA2014 aluminum alloys matrix resulting in improved hardness and tensile properties of the composites. The resulting composites exhibited enhanced wear resistance properties. The FSP method presented in this study has implications for extending the properties of other metal alloys, opening up new avenues for research in the field of materials science.

This study described a critical review of the biological system of self-curing agents and catalysts in which damage triggers an automatic healing response. In the first phase, a glass fiber-reinforced composite (GFRC) mono-leaf spring was prepared, which is made of glass fiber with a cement-based metal matrix. GFRC was further embedded with a microcapsule-based self-healing agent dicyclopentadiene (DCPD) that prevents sudden breakdown/failure of automobile suspension components resulting in micro-cracks produced in the material due to constant load application. In this paper, GFRC mono leaf spring samples were prepared with and without a healing agent under three different categories of varying thicknesses 20, 30, and 40 mm. In the second phase, the load-carrying capacity of all the samples was investigated and found a continuous increase in load-carrying capacity. Percentage increase in load carrying capacity before the time break was 1.09%, 1.42%, and 1.08% followed by time break of 05 min was 24.24%, 17.67%, and 21.67% respectively. It was clearly identified from the results that the addition of microcapsule-based healing substituents increases the load-carrying capacity of GFRC mono-leaf spring and avoids sudden fracture.

Abstract Graphene has superhigh thermal conductivity up to 5000 W/(m·K), extremely thin thickness, superhigh mechanical strength and nano-lamellar structure with low interlayer shear strength, making it possess great potential in minimum quantity lubrication (MQL) grinding. Meanwhile, ionic liquids (ILs) have higher thermal conductivity and better thermal stability than vegetable oils, which are frequently used as MQL grinding fluids. And ILs have extremely low vapor pressure, thereby avoiding film boiling in grinding. These excellent properties make ILs also have immense potential in MQL grinding. However, the grinding performance of graphene and ionic liquid mixed fluid under nanofluid minimum quantity lubrication (NMQL), and its tribological mechanism on abrasive grain/workpiece grinding interface, are still unclear. This research firstly evaluates the grinding performance of graphene and ionic liquid mixed nanofluids (graphene/IL nanofluids) under NMQL experimentally. The evaluation shows that graphene/IL nanofluids can further strengthen both the cooling and lubricating performances compared with MQL grinding using ILs only. The specific grinding energy and grinding force ratio can be reduced by over 40% at grinding depth of 10 μm. Workpiece machined surface roughness can be decreased by over 10%, and grinding temperature can be lowered over 50 ℃ at grinding depth of 30 μm. Aiming at the unclear tribological mechanism of graphene/IL nanofluids, molecular dynamics simulations for abrasive grain/workpiece grinding interface are performed to explore the formation mechanism of physical adsorption film. The simulations show that the grinding interface is in a boundary lubrication state. IL molecules absorb in groove-like fractures on grain wear flat face to form boundary lubrication film, and graphene nanosheets can enter into the grinding interface to further decrease the contact area between abrasive grain and workpiece. Compared with MQL grinding, the average tangential grinding force of graphene/IL nanofluids can decrease up to 10.8%. The interlayer shear effect and low interlayer shear strength of graphene nanosheets are the principal causes of enhanced lubricating performance on the grinding interface. EDS and XPS analyses are further carried out to explore the formation mechanism of chemical reaction film. The analyses show that IL base fluid happens chemical reactions with workpiece material, producing FeF2, CrF3, and BN. The fresh machined surface of workpiece is oxidized by air, producing NiO, Cr2O3 and Fe2O3. The chemical reaction film is constituted by fluorides, nitrides and oxides together. The combined action of physical adsorption film and chemical reaction film make graphene/IL nanofluids obtain excellent grinding performance.

Abstract Cutting fluid is crucial in ensuring surface quality and machining accuracy during machining. However, traditional mineral oil-based cutting fluids no longer meet modern machining’s health and environmental protection requirements. As a renewable, pollution-free alternative with excellent processing characteristics, vegetable oil has become an inevitable replacement. However, vegetable oil lacks oxidation stability, extreme pressure, and antiwear properties, which are essential for machining requirements. The physicochemical characteristics of vegetable oils and the improved methods’ application mechanism are not fully understood. This study aims to investigate the effects of viscosity, surface tension, and molecular structure of vegetable oil on cooling and lubricating properties. The mechanisms of autoxidation and high-temperature oxidation based on the molecular structure of vegetable oil are also discussed. The study further investigates the application mechanism and performance of chemical modification and antioxidant additives. The study shows that the propionic ester of methyl hydroxy-oleate obtained by epoxidation has an initial oxidation temperature of 175 ℃. The application mechanism and extreme pressure performance of conventional extreme pressure additives and nanoparticle additives were also investigated to solve the problem of insufficient oxidation resistance and extreme pressure performance of nanobiological lubricants. Finally, the study discusses the future prospects of vegetable oil for chemical modification and nanoparticle addition. The study provides theoretical guidance and technical support for the industrial application and scientific research of vegetable oil in the field of lubrication and cooling. It is expected to promote sustainable development in the manufacturing industry.

Natural fibre reinforced composites are being used in a variety of industries. Epoxy matrix composites reinforced with woven bamboo-cotton fibre has been fabricated via., hand lay-up technique and compression moulding technique. In the fabrication of the composite panels, the number of layers varied from 8 to 14 according to the weight of the fabric. The tensile, bending, impact, compression, water-absorption, and ILS properties for the developed composites have been tested or examined. SEM characterization was being used to examine the fractured morphology and assess interface-strength of the developed composites. It was found that increasing the number of fibre layers improved the composites' physico-mechanical properties. Due to the micro-voids, detachment, and hydrophilic nature of natural fibres, the cotton/bamboo twill fabric reinforced composites absorb the most water. In addition, the results have demonstrated that the fibre matrix debonding, which was actually the result of a weak-bonding amid the fibre and matrix, was the cause of the escalated water absorption behavior. Hence, the fabricated composites are suitable for the applications of moderate load bearing, including automobile body parts and structural components that require sufficient strength.

Natural fibre composites have emerged as a viable alternative to conventional polymer composites, after environmental concerns gain popularity. In recent years, a tremendous growth in the applications of natural fibre composites have been observed, particularly in the field of construction, as well as aerospace and automotive industries. The present study investigates the feasibility of developing a novel tribo-material by reinforcing biopolymer with easily accessible and inexpensive plant fibres from the surroundings. The fibres were treated chemically prior to fabrication. The injection molding process was used to fabricate laminated composites by incorporating three different kinds of fibres (sisal, banana, and bagasse) into Poly-lactic acid (PLA) matrix at 10% and 20% fibre concentrations. Wear properties of fabricated composites were studied on a digital display controlled pin-on-disc test rig. The test parameters under dry sliding conditions were sliding distance (1000–3000 m), sliding speed (2,4 and 6 m/s) and applied load (10 N). The experimental results depict that the incorporation of natural fibres improved tribological properties of neat PLA matrix. The worn surfaces of developed composites were examined using a scanning electron microscope to study the wear mechanism.

In present investigation, the impact of nanoparticle concentration on the machining accomplishment of Hastelloy C-276 has been examined in turning operation. The outputs like temperature, surface roughness, chip reduction coefficient (CRC), tool wear, and friction coefficient along with angle of shear have been estimated. The graphene nanoparticles (GnP) have been blended into soybean oil in distinct weight/volume ratio of 0.5, 1 and 1.5%. The experimental observations revealed that higher concentration of nanoparticles has enhanced the heat carrying capacity of amalgamation by 12.28%, surface roughness (27.88%), Temperature (16.8%), tool wear (22.5%), CRC (17.5%), coefficient of friction (46.36%) and shear angle (15%). Scanning electron microscopy identified nose wear, abrasion, adhesion and loss of tool coating. Further, lower tool wear has been noticed at 1.5% concentration, while the complete failure of insert has been reported during 116 m/min, 0.246 mm/rev having 0.5% concentration. ANOVA results exhibited that surface roughness is highly influenced by speed rate (41.66%) trailed by feed rate (28.16%) and then after concentration (13.68%). Temperature is dominated by cutting speed (69.31%), concentration (14.53%) and feed rate (13.25%). Likewise, tool wear was majorly altered by cutting speed (67.2%) accompanied by feed rate (23.90%) and thirdly concentration of GnP (5.03%).

Abstract Minimum quantity lubrication (MQL) is a relatively efficient and clean alternative to flooding workpiece machining. Electrostatic atomization has the merits of small droplet diameter, high uniformity of droplet size, and strong coating, hence its superiority to pneumatic atomization. However, as the current research hotspot, the influence of jet parameters and electrical parameters on the average diameter of droplets is not clear. First, by observing the shape of the liquid film at the nozzle outlet, the influence law of air pressure and voltage on liquid film thickness (h) and transverse and longitudinal fluctuations are determined. Then, the mathematical model of charged droplet volume average diameter (VAD) is constructed based on three dimensions of the liquid film, namely its thickness, transverse wavelength (λ h), and longitudinal wavelength (λ z). The model results under different working conditions are obtained by numerical simulation. Comparisons of the model results with the experimental VAD of the droplet confirm the error of the mathematical model to be less than 10%. The droplet diameter distribution span value Rosin-Rammler distribution span (R.S) and percentage concentrations of PM10 (particle size of less than 10 µm)/PM2.5 (particle size of less than 2.5 µm) under different working conditions are further analyzed. The results show that electrostatic atomization not only reduces the diameter distribution span of atomized droplets but also significantly inhibits the formation of PM10 and PM2.5 fine-suspension droplets. When the air pressure is 0.3 MPa, and the voltage is 40 kV, the percentage concentrations of PM10 and PM2.5 can be reduced by 80.72% and 92.05%, respectively, compared with that under the pure pneumatic atomization condition at 0.3 MPa.

Abstract Nanofluid minimum quantity lubrication (NMQL) is a green processing technology. Cottonseed oil is suitable as base oil because of excellent lubrication performance, low freezing temperature, and high yield. Al2O3 nanoparticles improve not only the heat transfer capacity but also the lubrication performance. The physical and chemical properties of nanofluid change when Al2O3 nanoparticles are added. However, the effects of the concentration of nanofluid on lubrication performance remain unknown. Furthermore, the mechanisms of interaction between Al2O3 nanoparticles and cottonseed oil are unclear. In this research, nanofluid is prepared by adding different mass concentrations of Al2O3 nanoparticles (0, 0.2%, 0.5%, 1%, 1.5%, and 2% wt) to cottonseed oil during minimum quantity lubrication (MQL) milling 45 steel. The tribological properties of nanofluid with different concentrations at the tool/workpiece interface are studied through macro-evaluation parameters (milling force, specific energy) and micro-evaluation parameters (surface roughness, micro morphology, contact angle). The result show that the specific energy is at the minimum (114 J/mm3), and the roughness value is the lowest (1.63 μm) when the concentration is 0.5 wt%. The surfaces of the chip and workpiece are the smoothest, and the contact angle is the lowest, indicating that the tribological properties are the best under 0.5 wt%. This research investigates the intercoupling mechanisms of Al2O3 nanoparticles and cottonseed base oil, and acquires the optimal Al2O3 nanofluid concentration to receive satisfactory tribological properties.

The underlying study propounds novel hyperbolic fuzzy entropy (HFE) and single valued neutrosophic entropy (NFE) based methodology for classifying the processing parameters employed for studying the wear-resistance of friction-stir-processing (FSP) of AA7075 aluminum, allow incorporated with B4C particles under different reinforcement conditions. Fast Fourier transform (FFT) was applied for the acquisition of vibration data. An alloy sheet with a thickness of 5 mm and dimensions 180×160×5 was machined on the aluminium plates for the purpose of accommodating B4C particles. The experiments were performed at varying tool rotational speeds (1400 rpm, 1500 rpm and 1600 rpm), feed rate (30 mm/min, 40 mm/min and 50 mm/min) with plunge depth and constant tilt angles of 3.14∘. After acquitting vibration data through FFT, the lower and upper bounds from energy eigenvalues of each processing parameters were extracted and thereafter rehabilitated into the forms of non-probabilistic sets, also called fuzzy sets (FSs) and single-valued neutrosophic sets (SVNSs) consecutively. The tool rotational speed of 1600 rpm with feed rate 30 mm/min was found to be the most superlative processing parameter owing to its maximum HFE and NFE values respectively. The wear-properties of the fabricated-samples were investigated employing pin-on tribometer. The investigations made in this study reveal that the fabricated specimen with tool rotational-speed 1600 rpm and feed-rate 30 mm/min was having higher wear resistance and coefficient-of-friction (COF). The proposed entropy-based method of classification of processing parameters can help the readers to improve surface integrity and enhancement of mechanical & chemical properties of the selected aluminium alloy as well as other related metal composites.

The transformation and upgrading of traditional agriculture are required to address its shortcomings and deficiencies, which have resulted in environmental pollution or water problems. Precision agriculture emerged at the historic moment to solve the current problems. Field information collection, information management and decision-making, and execution systems are the three key links of precision fertilization and irrigation. The technical principle and application of field information acquisition systems are analyzed. The information management and decision-making system describes the management and summary of information in crop growth. The execution system combines the knowledge of various disciplines and experts for targeted applications to specific crops. It further focuses on the core implementation system, that is, variable fertilization technology and variable spraying technology that can realize variable operations. Major contributions from different countries, institutions, corresponding authors, and journals are presented in detail. This study proposes several suggestions and ideas based on the research status and progress of the three key systems to provide a theoretical basis and technical support for the research and development of key technologies and innovative devices of precision agricultural fertilization and irrigation.

In the present study, waste of tasar silk fiber was used as reinforcement in the epoxy resin. Tasar silk fiber waste (TSFW) was pre-treated with NaOH coupling agent before reinforcing it with epoxy matrix. Treated and untreated TSFW-epoxy composites were made using the compression moulding technique. Composites were characterized for physical, mechanical and wear properties. Effect of NaOH coupling agent and fiber loading were examined on TSFW-epoxy composite. Comparatively, lower void fraction of 5.1% was obtained at 30% reinforcement of treated TSFW composite as compared to 5.8% as obtained for untreated TSFW composites. The tensile strength, flexural strength and impact strength were observed to be 68.47 MPa, 41.18 MPa, and 2.2 J for untreated TSFW where as these properties exhibites marginal increment of 70.86 MPa, 43.52 MPa and 2.35 J respectively. Hardness of composite experienced enhancement of 6% upon using treated TSFW. Overall, 10% reduction in specific wear was observed upon using treated TSFW as compared to untreated one. Scanning electron microscope (SEM) analysis suggested that the tensile specimen undergoes ductile fracture while flexural specimen failed in brittle manner. Fiber agglomeration and large deformation of tasar silk resulted in improved strength as observed in SEM analysis.

Hastelloy is categorized as difficult to cut superalloy widely used in aerospace, nuclear reactor components and chemical industry because of its magnificent strength and higher heat efficiency. Since, the machining of this material is quite difficult and hence suitable cooling systems are required to achieve sustainable manufacturing goals. The present investigation has been focused on the machining performance and sustainability assessment of turning Hastelloy C-276 in dry, flood and minimum quantity lubrication (MQL) environments. Taguchi L-9 array has been utilized to conduct and record the experimental output along with TOPSIS approach to evaluate the sustainability. The output responses viz. cutting forces, surface roughness, cutting temperature, energy consumption and carbon emission have been recorded at various levels of input variables. The experimental results revealed that MQL has minimized the cutting forces, surface roughness and temperature by margin of 20–38%. Likewise, energy expenditure and carbon emission was declined by 9–27% respectively compared to other conditions. Sustainability analysis explored best performance index during equal weightage criteria at 125 m/min, 0.246 and 0.8 mm doc under MQL. However, implementing assigned weightage system evaluated best condition for dry machining as 88 m/min and 0.246 mm/rev having same doc. SEM analysis of insert reported mainly abrasion and adhesion type of tool wear at all parametric range and machining conditions.

Minimizing the negative effects of the manufacturing process on the environment, employees, and costs while maintaining machining accuracy has long been a pursuit of the manufacturing industry. Currently, the nanofluid minimum quantity lubrication (NMQL) used in cutting and grinding has been studied as a useful technique for enhancing machinability and empowering sustainability. Previous reviews have concluded the beneficial effects of NMQL on the machining process and the factors affecting them, including nanofluid volume fraction and nanoparticle species. Nevertheless, the summary of the machining mechanism and performance evaluation of NMQL in processing different materials is deficient, which limits preparation of process specifications and popularity in factories. To fill this gap, this paper concentrates on the comprehensive assessment of processability based on tribological, thermal, and machined surface quality aspects for nanofluids. The present work attempts to reveal the mechanism of nanofluids in processing different materials from the viewpoint of nanofluids’ physicochemical properties and atomization performance. Firstly, the present study contrasts the distinctions in structure and functional mechanisms between different types of base fluids and nanoparticle molecules, providing a comprehensive and quantitative comparative assessment for the preparation of nanofluids. Secondly, this paper reviews the factors and theoretical models that affect the stability and various thermophysical properties of nanofluids, revealing that nanoparticles endow nanofluids with unique lubrication and heat transfer mechanisms. Finally, the mapping relationship between the parameters of nanofluids and material cutting performance has been analyzed, providing theoretical guidance and technical support for the industrial application and scientific research of nanofluids.

Abstract The application of cutting fluid in the field of engineering manufacturing has a history of hundreds of years, and it plays a vital role in the processing efficiency and surface quality of parts. Among them, water-based cutting fluid accounts for more than 90% of the consumption of cutting fluid. However, long-term recycling of water-based cutting fluid could easily cause deterioration, and the breeding of bacteria could cause the cutting fluid to fail, increase manufacturing costs, and even endanger the health of workers. Traditional bactericides could improve the biological stability of cutting fluids, but they are toxic to the environment and do not conform to the development trend of low-carbon manufacturing. Low-carbon manufacturing is inevitable and the direction of sustainable manufacturing. The use of nanomaterials, transition metal complexes, and physical sterilization methods on the bacterial cell membrane and genetic material could effectively solve this problem. In this article, the mechanism of action of additives and microbial metabolites was first analyzed. Then, the denaturation mechanism of traditional bactericides on the target protein and the effect of sterilization efficiency were summarized. Further, the mechanism of nanomaterials disrupting cell membrane potential was discussed. The effects of lipophilicity and the atomic number of transition metal complexes on cell membrane penetration were also summarized, and the effects of ultraviolet rays and ozone on the destruction of bacterial genetic material were reviewed. In other words, the bactericidal performance, hazard, degradability, and economics of various sterilization methods were comprehensively evaluated, and the potential development direction of improving the biological stability of cutting fluid was proposed.

Rotating machine is a common class of machinery in most of the industry and the main root cause of machinery failure is a faulty bearing. Bearings are most widely used in various types of machine elements ranging from small to heavy machinery and the common cause of machinery failure is a fault in bearings. Bearing faults can be external or internal which mainly depends on different operating conditions and these faults may cause severe damage to rotating components in machinery. Signal processing methods have traditionally been used to diagnose faults in tapered roller element bearings. A wavelet transform is the most common and effective tool for understanding and analyzing the vibration signal of bearings as it is responded quickly and observed sudden changes along with the transient impulses in the signal caused by faults in the different parts of bearing elements. In this article, localized fault's position and size on the outer ring of tapered roller bearing were investigated. Three different real values wavelets (DB2, Meyer, and Morlet) are analyzed as per Simple Sensitivity index criteria. Finally, experiments are carried out with four sets of bearing having fault on outer racing of bearing, and for the estimation of fault size, the setup was misaligned at ranging (0.00mm–1.50 mm) with a uniform deviation of 0.50 mm for each experiment. Shannon entropy was calculated for the identification of localized size of the faults with wavelets nomenclature, the result of DB2, Morlet, and Meyer wavelets at high-frequency zone are presented.The scanning electron microscope (SEM) has been taken for the estimation of size of the fault. The proposed method has been successfully implemented for measuring defect width and size. Also, it has been observed that with increased magnification level from 0.00 mm to 0.50 mm, the crack width of the faulty bearing was increased by 0.813 mm, and whenever on further increase in magnification level of 0.50, 1.00 mm and 1.50 mm the crack width of the faulty bearing was increased by 2.568 mm and 3.856 respectively.

“External magnetic-field (EMF)” has been proved as an additional process parameter like voltage and current affecting the weld arc form, molten metal-flow, microstructure, and characteristics of the weld joint. This article analyzed the research work that has been done to promote EMF application in welding and discussed the recent development trends and research in the design and fabrication of EMF setup to the controlled arc welding process. It is found that even after the successful application of EMF in welding. Still, there is no mass level initiation to integrate EMF with welding machines that hinder researchers and manufacturers to accept it as a regular process parameter to control weld quality.

The thermal performance of a flat plate solar collector using MWCNT + Fe3O4/Water hybrid nanofluids was examined in this research. The flat plate solar collector was tested using different nanofluid concentrations and flow rates in an arid environment. A significant enhancement in coefficient of heat transfer (26.3%) with a marginal loss on pressure drop due to friction factor (18.9%). The data collected during experimental testing was utilized to develop novel prediction models for efficient heat transfer, Nusselt's number, friction factor, and thermal efficiency. The modern ensemble machine learning techniques Boosted Regression Tree (BRT) and Extreme Gradient Boosting (XGBoost) were used to develop prognostic models for each parameter. A battery of statistical methods and Taylor’s graphs were used to compare the performance of these two modern ML techniques. The value of R2 for the BRT-based prediction models were 0.9619 - 0.9994 and 0.9914 - 0.9997 for XGBoost-based models. The mean squared error was quite low for all the models (0.000081 - 9.11), while the mean absolute percentage error was negligible from 0.0025 to 0.3114. The comprehensive statistical analysis of the prognostic model was complemented with Taylor’s graphs to develop an improved comparison paradigm, to reveal the superiority of XGBoost over BRT.