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Electrostatic atomization minimum quantity lubrication (EMQL) employs the synergistic effect of multiple physical fields to atomize minute quantities of lubricant. This innovative methodology is distinguished by its capacity to ameliorate the atomization attributes of the lubricant substantially, which subsequently augments the migratory and infiltration proficiency of the droplets within the complex and demanding milieu of the cutting zone. Compared with the traditional minimum quantity lubrication (MQL), the EMQL process is further complicated by the multiphysical field influences. The presence of multiple physical fields not only increases the complexity of the forces acting on the liquid film but also induces changes in the physical properties of the lubricant itself, thus making the analysis of atomization characteristics and energy distribution particularly challenging. To address this objective reality, the current study has conducted a meticulous measurement of the volume average diameter, size distribution span, and the percentage concentration of inhalable particles of the charged droplets at various intercept positions of the EMQL nozzle. A predictive model for the volume-averaged droplet size at the far end of the EMQL nozzle was established with the observed statistical value F of 825.2125, which indicates a high regression accuracy of the model. Furthermore, based on the changes in the potential energy of surface tension, the loss of kinetic energy of gas, and the electric field work at different nozzle orifice positions in the EMQL system, an energy distribution ratio model for EMQL was developed. The energy distribution ratio coefficients under operating conditions of 0.1 MPa air pressure and 0 to 40 kV voltage on the 20 mm cross-section ranged from 3.094‰ to 3.458‰, while all other operating conditions and cross-sections had energy distribution ratios below 2.06‰. This research is expected to act as a catalyst for the progression of EMQL by stimulating innovation in the sphere of precision manufacturing, providing theoretical foundations, and offering practical guidance for the further development of EMQL technology. [ABSTRACT FROM AUTHOR]

The traditional alkaline peeling method generates high‐salinity wastewater, posing significant environmental risks. To avoid water waste and chemical use, a dry method using high‐temperature thermal radiation was explored for removing walnut skins. The mechanism of the high‐temperature thermal radiation dry method for removing walnut skins was revealed by studying the physical properties of walnut kernels. Research on the performance of the peeling device identified the optimal parameters: an infrared emitter surface temperature of 600°C, a radiation time of 20.7 seconds, and a distance of 129.46 mm between emitters, achieving a 95.18% skin removal rate with only 0.8% moisture loss and a quality score of 96.82. Raman spectroscopy showed that this method increased the unsaturated fatty acid content of walnut kernels by 27.26%, greatly enhancing their quality. SEM analysis revealed different microstructural changes between skins removed by infrared and alkaline methods, revealing the differences in their peeling mechanisms. These findings provide a scientific foundation for developing thermal radiation dry peeling technology and devices. Practical applications: The removal of walnut skins is an essential process for enhancing the added value of products. However, current industrial peeling methods such as hot alkaline peeling and steam peeling are water and energy‐intensive industries, generating large amounts of wastewater that negatively impact the environment. There is an urgent need to develop an efficient, green, and environmentally friendly dry peeling technology for walnut kernels in the food industry to replace traditional chemical peeling methods. The high‐temperature thermal radiation dry peeling technology provides a new approach that avoids the use of water and chemical reagents while maintaining high product quality after peeling. Research focuses on the theoretical study and several key points of dry peeling technology for achieving walnut kernel peeling. The research results provide scientific basis for the replacement of traditional alkaline peeling with high‐temperature thermal radiation dry peeling technology and offer theoretical support and reference for the development and optimization of related equipment. [ABSTRACT FROM AUTHOR]

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 FROM AUTHOR]

In the present competitive landscape industry, individuals have emphasized fulfilling the consumer needs in available resources and limited constraints. However, the industry individuals face several problems in achieving operational efficiency. These problems include ergonomics issues, environmental waste, work processes waste, inobservance on the shop floor, and workers' apathy. The operations management teams use various approaches to improve operational excellence on the shop floor, including lean manufacturing, smart manufacturing, green manufacturing, and artificial neural network. These approaches are used to enhance productivity by eliminating problems in the operations management on the shop floor. The present research aims to develop a framework for improvement in operational excellence and sustainability in operations management on the shop floor in an industry 4.0 environment using lean, green, and smart manufacturing concepts. In the study, a strategic ergonomics assessment and environmental assessment have been used to assess working and operational performance on the shop floor. The adaptability of the developed framework has been investigated by implementing it in mining machinery manufacturing industry. The framework has been developed with insights gained from previous research, industry individuals, and brainstorming analysis on problems faced in operations management on the shop floor in industry 4.0 working environment. The novelty of the present study lies in the fact that no model has been developed for achieving operational excellence on the shop floor in industry 4.0 using the smart, lean green manufacturing concept. The developed framework significantly improved productivity by 85%, improved machinery utilization by 21%, reduced production time by 65%, reduced manufacturing defects by 96%, and production cost by 75%. The present research work strongly believe that the developed model would benefit industry individuals in enhancing sustainability in operational excellence on the shop floor in industry 4.0 environment by establishing a more competent and cleaner working environment with available resources. [ABSTRACT FROM AUTHOR]

The nickel-based high-temperature alloy GH4169 is the material of choice for manufacturing critical components in aeroengines, and electrostatic atomization minimum quantity lubrication (EMQL) milling represents a fundamental machining process for GH4169. However, the effects of electric field parameters, jet parameters, nozzle position, and milling parameters on milling performance remain unclear, which constrains the broad application of EMQL in aerospace manufacturing. This study evaluated the milling performance of EMQL on nickel-based alloys using soybean oil as the lubrication medium. Results revealed that compared with conventional pneumatic atomization MQL milling, EMQL reduced the milling force by 15.2%–15.9%, lowered the surface roughness by 30.9%–54.2%, decreased the average roughness spacing by 47.4%–58.3%, and decreased the coefficient of friction and the specific energy of cutting by 55% and 19.6%, respectively. Subsequent optimization experiments using orthogonal arrays demonstrated that air pressure most significantly affected the milling force and specific energy of cutting, with a contribution rate of 22%, whereas voltage had the greatest effect on workpiece surface roughness, contributing 36.71%. Considering the workpiece surface morphology and the potential impact of droplet drift on environmental and health safety, the optimal parameter combination identified were a flow rate of 80 mL/h, an air pressure of 0.1 MPa, a voltage of 30 kV, a nozzle incidence angle of 35°, an elevation angle of 30°, and a target distance of 40 mm. This research aimed to provide technical insights for improving the surface integrity of aerospace materials that are difficult to machine during cutting operations. [ABSTRACT FROM AUTHOR]

Functionally graded piezoelectric structures (FGPSs) have excellent electromechanical properties and are promising for engineering applications. However, the inhomogeneous material properties and piezoelectric effects create great difficulties in the mechanical analysis of the FGPSs. In this paper, a Hermite interpolation element-free Galerkin method (HIEFGM) is proposed for the numerical analysis of the FGPSs. The HIEFGM utilizes a set of nodes to represent the problem domain, which can ideally reflect the inhomogeneous material properties of the FGPSs. Firstly, the governing equations of the FGPSs are derived through the constitutive equation, equilibrium equation, and boundary conditions. Secondly, the approximating function of the field quantities is obtained by the improved moving least-square method and Hermite interpolation. The HIEFGM formulation of the FGPSs is obtained using the variational principle. Furtherly, the influence of weight function, scaling parameter, and node densities on the HIEFGM of the FGPSs is discussed in detail through a parameter study. Finally, the availability of present method is estimated by several examples with different configurations and boundary conditions. The influence of gradation exponent on the electromechanical responses of the FGPSs is analyzed. The results show that the present method has excellent accuracy and stability in analyzing the FGPSs. As the gradation exponent increases, the distribution of the field quantities of the FGPSs exhibits nonlinear characteristics. This work may provide an effective methodology for the analysis of the FGPSs, and contribute to the theoretical research and engineering application of the FGPSs. [ABSTRACT FROM AUTHOR]

Ti6Al4V, as an excellent high-temperature alloy, finds widespread application in key components within industries such as aerospace, automotive, and others. However, due to its high hardness and low thermal conductivity, conventional turning of Ti6Al4V often leads to significant cutting forces and elevated cutting temperatures. Consequently, this imposes higher performance requirements on cutting tools. In dry cutting or with a cooling strategy, micro-texture tools exhibit better cutting performance than conventional tools. This paper investigates the performance of the edge margin complex micro-texture tool and its influence on the machined surface during cutting Ti6Al4V. Through experiments and numerical simulations of the Ti6Al4V cutting process, the cutting performance of four different types of tools is studied. Simulation models of different cutting tools are established, and changes in cutting force, thrust force, cutting temperature, and Von Mises Stress are compared. The results indicate that, compared with the round edge tool, the maximum temperature decreases by up to 16.7%, and the maximum Von Mises Stress decreases by up to 69.6% with the edge margin complex rectangular micro-texture cutting tool. Moreover, the occurrences of self-excited vibration with the other three types of tools decrease by 4.3% to 48.6%. These findings contribute to improving surface quality and prolonging the life of cutting tools when cutting Ti6Al4V with the edge margin complex rectangular micro-texture cutting tool. [ABSTRACT FROM AUTHOR]

In the present scenario, controlling surface characteristics of superalloys such as friction, wear rates, and fatigue failure needs special attention for various manufacturing applications. The present research work deals with the analyses of a fiber laser surface texturing of Hastelloy C-276 to utilize the generated surfaces for high power applications. Texturing on Hastelloy C-276 surface has been achieved with the overlapping of linear micro-grooves. The effects of laser process parameters like laser power, scan speed, pulse frequency, and duty cycle on the surface morphology like arithmetic mean surface roughness (Ra), skewness (Rsk), and kurtosis (Rku) have been studied. Empirical modeling of the process parameters for fiber laser surface texturing of Hastelloy C-276 has been carried out by response surface methodology. A sensitivity analysis is conducted here to find out the sensitivity of process variables on surface characteristics. The combination of laser power of 19.93 W, pulse frequency of 60 kHz, a duty cycle of 38.96%, and a scan speed of 8.41 mm/s lead to the optimized roughness criteria are 1.2 μm, − 0.35, and 3 for Ra, Rsk, and Rku respectively. [ABSTRACT FROM AUTHOR]

SiC particle–reinforced Al metal matrix composites (SiCp/Al) are typical difficult-to-machine materials due to the heterogeneous constituent. In order to explore the material removal mechanism in fixed abrasive polishing (FAP), polishing experiments were performed on SiCp/Al at 15 rpm and 35 rpm respectively, and surface integrity, including surface damage and material removal forms, was evaluated to explore the effects of different polishing speeds on it. The results indicate that high-speed polishing at 35 rpm may result in better surface quality. The polished SiC surface changes from a concave cavity to a fish scale shape, and the removal form of SiC particles changes from whole extraction and brittle fracture to ductile removal. A removal model for SiCp/Al in consolidated abrasive polishing was established, and the material removal mechanism was revealed. Simulate the removal of SiC particles at different depths using molecular dynamics simulation. We find dislocations will generate not only at the polishing region but also at the SiC–Al interface. Moreover, the motion of dislocations is obstructed by the nanoparticles, resulting in accumulation of dislocations between the tool and particles. Furthermore, it was found that the removed silicon carbide particles exhibited three-body wear during low-speed polishing, while they turned into two-body wear during high-speed polishing. Material removal rate (MRR) data showed that the standard deviation was reduced by 80% when switching from low-speed to high-speed polishing. This significant decrease underscores that high-speed polishing helps to improve SiCp/Al surface quality. Our researches benefit to understand the mechanical removal mechanism of SiCp/Al substrates and give theoretical guide for improving the machining technology of FAP. [ABSTRACT FROM AUTHOR]

Metallic glass has been widely used in aviation, medical, military, and other fields because of its excellent performance. In view of the poor processability of metallic glass, the introduction of ultrasonic vibration provides a unique idea for it. In order to further explore the influence of ultrasonic vibration on trajectory and machining effect, this paper focuses on the theoretical feasibility of generating a unique type of tool path under different parameter combinations and studies the machining effect of metal glass under this condition. The experimental results show that the frequency coefficient, amplitude, and phase difference are all important parameters that affect the characteristics of tool path and the machining effect of metallic glass. The tool path formed by the appropriate phase difference and frequency coefficient will greatly improve the surface morphology, and the separation characteristics formed under the appropriate parameters can reduce the cutting force by about 50%. In addition, the effect of ultrasonic vibration machining with a frequency coefficient of 2 is the best, the cutting force generated is similar to that of elliptical ultrasonic vibration machining, and the roughness is reduced by nearly 50%. Choosing the appropriate parameters will get the ultrasonic vibration tool path with a positive effect, and will greatly improve the machining quality of metallic glass. [ABSTRACT FROM AUTHOR]

Bearings are pivotal components in mechanical systems, providing crucial support to rotating bodies. However, traditional bearings are susceptible to failure caused by friction and wear. This vulnerability is particularly pronounced in scenarios involving ultrahigh speeds and extreme conditions, necessitating the minimization of bearing losses and the enhancement of performance. Magnetic bearings, distinguished by their frictionless operation, absence of lubrication requirements, and high-speed capabilities, offer a promising solution to mitigate bearing failure attributable to friction. Nevertheless, a comprehensive review of magnetic bearings, encompassing their structural attributes, modeling mechanisms, and control strategies, is currently lacking in the literature. This paper aims to address this gap by conducting an exhaustive literature review on magnetic bearings. The objective is to provide scientists with a profound understanding of the structural characteristics, operational mechanisms, control performance, and future development trajectories of this technology. The paper begins by categorizing various magnetic bearings and conducting an in-depth analysis of their properties and characteristics, focusing on their magnetic circuit structures. Subsequently, it delves into the working principles and performance of mathematical models for magnetic bearings with different configurations, outlining the modeling procedures and optimization approaches. Additionally, the paper highlights the impact of control strategies on the performance of magnetic bearings. Modern control theory has demonstrated a remarkable 50% improvement in position accuracy and adjustment time compared to traditional PID control. Finally, the paper offers a glimpse into the future of magnetic bearing design, modeling mechanisms, and control strategies, presenting prospective directions for further advancements in this field. [ABSTRACT FROM AUTHOR]

In the aircraft industry, Ti6Al4V is often used due to its good strength and excellent comprehensive performance. However, because of its particularity, the titanium alloy material itself makes the processing difficult. In the current research, the research on the force of machining, heat flow, and stress on machined surfaces produced when machining titanium alloy is not enough, especially for the residual stress has not been able to give a more accurate numerical solution. The main work of this essay includes the following: a planar orthogonal cutting model is established by finite element method (FEM), and the cutting mechanism is studied based on the established model. Combining previous work, the cutting temperature model was analyzed and the relationship between the distance from machined surface and residual temperature of the processed workpiece is discussed. Simulations are performed on the cutting temperature field under different processing conditions. Furthermore, on the basis of the model of cutting force and temperature, it was proposed that the residual stress versus depth curve can be an exponential function and a linear superposition of high-order Gaussian functions. This research has certain significance in revealing the mechanism of cutting force and residual stress formation in difficult-to-machine materials. [ABSTRACT FROM AUTHOR]

The increasing interest in wearable smart healthcare systems has sparked considerable attention toward flexible sensors owing to their high sensitivity and flexibility. However, these sensors still face challenges in terms of performance imbalances and instability. To address these issues, graphene-based conductive materials with exceptional mechanical and electrical properties have been incorporated into flexible sensors. Despite the potential of graphene, a comprehensive understanding of the sensing mechanisms and influence of fabrication methods on the performance of graphene-based flexible sensors is lacking. This article aims to bridge this gap by providing an overview of the latest research progress in flexible graphene sensors. We begin by analyzing the main properties of graphene materials, including tensile strength, specific surface area, thermal conductivity, and electrical conductivity. These properties highlight the superior characteristics of graphene for flexible sensor applications. The sensing mechanisms of strain/pressure, gas, and temperature flexible sensors are reviewed, with a focus on innovations in graphene composites, regular microstructures, and emerging preparation methods that enable an effective balance of the individual properties of a single flexible sensor. Furthermore, the article discusses graphene-based multifunctional flexible sensors that allow for the simultaneous monitoring of multiple stimuli, self-powered performance studies, and wireless communication performance studies. Performance analysis of these sensors in the context of flexible systems is provided. Finally, this article presents a comprehensive summary of flexible graphene sensors and offers an outlook for the future. We aim to provide theoretical guidance and technical support for the realization of individual whole-life physical sign detection using flexible graphene-based sensors. [ABSTRACT FROM AUTHOR]

Nickel-based alloys have great application value in aerospace, biomedical industry, chemical industry, and other fields. However, nickel-based alloys are known to be difficult to process, which will generate a lot of heat and friction during processing, which limits the application range of nickel-based alloys. Therefore, a large amount of cutting fluid needs to be used during processing, and the cutting fluid will cause harm to human health and the environment. In order to solve these problems, scholars proposed to use the minimum quantity lubrication (MQL) to replace the conventional flood cooling lubrication technique. Recently, many papers have proposed to use MQL for lubrication /cooling in the processing of nickel-based alloys. However, few studies have approached this topic comprehensively. To bridge this gap, this study conducts a comprehensive literature review of the progress made in the processing of nickel-based alloys using various MQL methods. It should be noted that these studies are divided into four categories: vegetable oil-based MQL, cryogenic cooling-based MQL, solid lubricant-based MQL, and electrostatic atomization-based MQL. It is crucial to compare the advantages of these cooling and lubricating technologies in machining nickel-based alloys, analyze their experimental results, and assess their impact on machining quality and tool wear. This review reveals that compared to traditional MQL, vegetable oil-based MQL is more energy-saving and environmentally friendly, resulting in approximately 30% improvement in surface quality and a 50% reduction in tool wear. The addition of solid lubricants to vegetable oil further enhances its lubrication performance. Cryogenic cooling-based MQL enables the attainment of finer grains and smaller sawtooth chips. Electrostatic atomization MQL, by altering the atomization process of traditional MQL, produces more uniform droplets, leading to a 42.4% reduction in tool wear and a 47% improvement in machined surface quality. The purpose of this paper is to help researchers identify existing gaps and to enable MQL to improve the processing quality and application range of nickel-based alloys. Finally, the present technical challenges and future research directions are put forward. [ABSTRACT FROM AUTHOR]

Ultrasonic vibration-assisted (UVA) cutting is an advanced technique to improve the machinability and productivity of difficult-to-machine materials. This paper aims to assess the cutting performance of ultrasonic vibration-assisted milling (UVAM) technique and conventional milling (CM) in side milling of Ti–6Al–4 V. Tool trajectory and instantaneous chip thickness are calculated considering tool runout, vibration, and deflection. The geometric-kinematic-dynamic surface topography matrix and its corresponding material elastic recovery height matrix are reconstructed based on tool trajectory and cutting thickness, which are then summed to obtain the geometric-kinematic-dynamic-physical surface topography matrix. Finally, roughness parameters Ra and Rz are predicted based on the final reconstructed physical surface topography matrix. Experimental results show that Ra and Rz of UVAM are on average 26 and 39% greater, respectively, compared to CM due to the presence of high-frequency ultrasonic vibration-induced texture patterns in the feed grooves. The average prediction error for Ra and Rz is 23%, proving the validity of the prediction model. UVAM reduces the radial and tangential cutting force coefficients and ploughing force coefficients compared to CM due to the separation and impact effect of ultrasonic vibration. However, UVAM leads to an increase in the axial ploughing force coefficient because ultrasonic vibration introduces relative motion and friction between the tool and the workpiece in the axial direction. [ABSTRACT FROM AUTHOR]

Nanofluids are efficient heat transfer media that have been developed over the past 27 years and have been widely used in the electronic microchannel, engine, spacecraft, nuclear, and solar energy fields. With the high demand for efficient lubricants in manufacturing, the application of nanofluids in machining has become a hot topic in academia and industry. However, in the context of the huge amount of literature in the past decade, existing review cannot be used as a technical manual for industrial applications. There are many technical difficulties in establishing a mature production system, which hinder the large-scale application of nanofluids in industrial production. The physicochemical mechanism underlying the application of nanofluids in machining remains unclear. This paper is a complete review of the process, device, and mechanism, especially the unique mechanism of nanofluid minimum quantity lubrication under different processing modes. In this paper, the preparation, fluid, thermal, and tribological properties of nanofluids are reviewed. The performance of nanofluids in machining is clarified. Typically, in friction and wear tests, the coefficient of friction of jatropha oil-based alumina nanofluids is reduced by 85% compared with dry conditions. The cutting fluid based on alumina nanoparticles improves the tool life by 177–230% in hard milling. The addition of carbon nanotube nanoparticles increases the convective heat transfer coefficient of normal saline by 145.06%. Furthermore, the innovative equipment used in the supply of nanofluids is reviewed, and the atomization mechanisms under different boundary conditions are analyzed. The technical problem of parameterized controllable supply system is solved. In addition, the performance of nanofluids in turning, milling, and grinding is discussed. The mapping relationship between the nanofluid parameters and the machining performance is clarified. The flow field distribution and lubricant wetting behavior under different tool-workpiece boundaries are investigated. Finally, the application prospects of nanofluids in machining are discussed. This review includes a report on recent progress in academia and industry as well as a roadmap for future development. [ABSTRACT FROM AUTHOR]

Surface roughness has a significant influence on the mechanical properties and service life of a component. During face milling, surface roughness greatly varies in the tool step direction and can be controlled by using a surface roughness prediction model. However, the issues of accuracy and efficiency of surface roughness prediction models have not been adequately addressed. This study aims to address these research constraints. An improved surface roughness prediction model is proposed, taking into consideration the influences of insert back cutting and stepover ratio. First, the profile-forming mechanism is analyzed based on geometry and kinematics. Subsequently, an improved surface roughness prediction model is established. Thereafter, the influence of feed per tooth, stepover ratio, corner radius, and minor cutting edge angle on surface roughness are analyzed through numerical simulation. Finally, the experiment of face milling aerospace aluminum alloy 7075 is suggested to verify the improved model, and the Z-Map model is introduced for comparison. Results show that the surface roughness is nonlinear with a feed per tooth and stepover ratio, a monotonic variation with corner radius, and a minor cutting edge angle. The predicted values of the improved model and the Z-Map model for the Rsm are equal to the experimental values. However, the improved model reduces the prediction error of Ra from 11.2 to 4.2% in the non-overlapping compared with the Z-Map model and from 62.58 to 13.34% in the overlapping. In addition, the improved model performs better than the Z-Map model in predicting the shape parameters. This work serves as a significant reference for selecting and optimizing the milling parameters to enable machining quality control. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Nanoparticle-enhanced coolants (NPECs) are increasingly used in minimum quantity lubrication (MQL) machining as a green lubricant to replace conventional cutting fluids to meet the urgent need for carbon emissions and achieve sustainable manufacturing. However, the thermophysical properties of NPEC during processing remain unclear, making it difficult to provide precise guidance and selection principles for industrial applications. Therefore, this paper reviews the action mechanism, processing properties, and future development directions of NPEC. First, the laws of influence of nano-enhanced phases and base fluids on the processing performance are revealed, and the dispersion stabilization mechanism of NPEC in the preparation process is elaborated. Then, the unique molecular structure and physical properties of NPECs are combined to elucidate their unique mechanisms of heat transfer, penetration, and antifriction effects. Furthermore, the effect of NPECs is investigated on the basis of their excellent lubricating and cooling properties by comprehensively and quantitatively evaluating the material removal characteristics during machining in turning, milling, and grinding applications. Results showed that turning of Ti–6Al–4V with multi-walled carbon nanotube NPECs with a volume fraction of 0.2% resulted in a 34% reduction in tool wear, an average decrease in cutting force of 28%, and a 7% decrease in surface roughness Ra, compared with the conventional flood process. Finally, research gaps and future directions for further applications of NPECs in the industry are presented. [ABSTRACT FROM AUTHOR]

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 (λh), and longitudinal wavelength (λz). 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 FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 FROM AUTHOR]

Conventional lubrication systems are used in grinding operations to reduce friction and defects produced during machining. Mineral-based oils, commonly used as conventional lubricants, were observed to produce greenhouse wastes that are hazardous to the environment. The minimum quantity lubrication (MQL) system, an eco-friendly, economical, and less hazardous lubrication technique, is affirmed to be an efficient substitute for these conventional lubricants. Nevertheless, the pure vegetable and synthetic oils used in MQL systems have lower tribological and thermal evacuation properties compared to conventional lubricants. Many adjustments and improvements have been introduced into the MQL system such as the introduction of nanofluids, cryogenic air, ionic fluids, and electrostatic atomization. This study aims to come up with an extensive review and analytical assessment of the trends and developments of the MQL system in grinding operations. Firstly, the different advances ranging from fluid types, additives, and redesigns of the MQL systems are discussed. Likewise, the results obtained from using different types of lubricants and nanofluids in the MQL system were discussed. Moreover, a detailed comparative assessment of the grinding performances between the MQL systems, dry grinding, and conventional lubrication was provided. It was found that the nanofluid MQL system produced 60% lower surface roughness and reduced the grinding forces by 30% compared to flood cooling systems. Lastly, the area of focus for research on grinding with MQL system for future advancements was proposed. The various advancements include the introduction of nanofluid varieties and the overall modification of the grinding system. [ABSTRACT FROM AUTHOR]

Cooperative co-evolution (CC) is an evolutionary algorithm that adopts the divide-and-conquer strategy to solve large-scale optimization problems. It is difficult for CC to specify a suitable subpopulation size to solve different subproblems. The population diversity may be insufficient to search for the global optimum during subpopulations' evolution. In this paper, an adaptive method for enhancing population diversity is embedded in a contribution-based CC. In CC, there are two kinds of subpopulation: the convergent or stagnant subpopulations and the non-convergent and non-stagnant subpopulations. A method is proposed in the paper to evaluate the convergent and stagnant subpopulations' contributions to improving the best overall objective value, which is different from the contribution evaluation on the non-convergent and non-stagnant subpopulations. In each co-evolutionary cycle, the new CC adaptively determines to select a subpopulation, which can make a greater contribution to improving the best overall objective value, between the above two kinds of subpopulation to undergo evolution. When a convergent or stagnant subpopulation is selected to undergo evolution, the subpopulation is re-diversified to enhance its global search capability. Our experimental results and analysis suggest that the new CC algorithm can improve the performance of CC and serves as a competitive solver for large-scale optimization problems. [ABSTRACT FROM AUTHOR]

Mushroom residues and swine manure are two common types of agricultural waste that are often returned to fields as organic fertilizers. However, the environmental risks of their reclamation, such as heavy metal pollution, have been less studied. To investigate the potential risks of heavy metal contamination in soils and vegetables after continuously applying mushroom residues and swine manure, field experiments of four consecutive vegetable rotations were conducted in the Qingpu District of Shanghai, Southeast China, from 2019 to 2021. The concentrations of heavy metals in soils continuously fertilized with mushroom residues and swine manure gradually increased. The organic matter content in the soils exhibited a significant correlation with the concentrations of Cu, Zn, Pb, and Cd (p < 0.01), suggesting that the increase in heavy metals is attributed to the use of organic waste. In particular, the application of swine manure increased Cu, Zn, Pb, and Cd concentrations in the soils by 118.3%, 54.9%, 57.6%, and 122.2%, respectively. Moreover, the application of organic waste raised the risk of the bioaccumulation of toxic metals, such as Cd, in vegetables. The Cd concentration was significantly and positively correlated with Zn in the edible parts of vegetables (p < 0.05). The recycling of swine manure more significantly enhanced Cd concentrations in the edible parts of green pepper (Capsicum annuum), eggplant (Solanum melongena), Brassica chinensis, and lettuce (Lactuca sativa), which were 2.53, 1.55, 1.66, and 1.62 times that of the non-fertilizer control (CK), respectively. Although the increase in heavy metals in the soils and vegetables was still mild when compared with the set thresholds of soil and food safety after the four vegetable rotations, the trend of increase in toxic heavy metals in the food chain with a continuous application of organic waste should be carefully considered. [ABSTRACT FROM AUTHOR]

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 FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

In this paper, three kinds of Ni–20Cr coatings were deposited on SA516 substrate steel by cold-sprayed coating technique. Physical properties (such as hardness, surface roughness, and residual stress) and slurry erosion behavior (with impingement angles of 30∘ and 90∘) of cold-sprayed substrates have been evaluated. Moreover, a scanning electron microscope (SEM) examination has been performed to evaluate the morphological characterization of various coatings. It has been found that the residual stresses induced in the coated specimens exhibited compressive nature. Further, micro-hardness and surface roughness was observed to proliferate with the incorporation of titanium carbide (TiC) and rhenium (Re) in Ni–Cr coatings. Micro-hardness for Ni–20Cr+TiC and Ni–20Cr+TiC+Re was observed at 233.67 and 278.9 Hv, respectively, where Surface roughness for Ni–20Cr+TiC and Ni–20Cr+TiC+Re was observed at 9.86 and 11.68 μ m, respectively. All types of Ni–20Cr coatings were quite efficient in reducing the erosion rate of the SA516 steel as compared to uncoated SA516 and most prominent of all was Ni–20Cr+Tic+Re coating. It was observed that at 30∘, weight loss for Ni–20Cr, Ni–20Cr+TiC and Ni–20Cr+TiC+Re was up to 0.00027, 0.00015 and 0.00012 g/mm2, whereas at 90∘, weight loss was for Ni–20Cr, Ni–20Cr+TiC and Ni–20Cr+TiC+Re was up to 0.00024, 0.00014 and 0.00012 g/mm2. [ABSTRACT FROM AUTHOR]

Model management is an essential component in data-driven surrogate-assisted evolutionary optimization. In model management, the solutions with a large degree of uncertainty in approximation play an important role. They can strengthen the exploration ability of algorithms and improve the accuracy of surrogates. However, there is no theoretical method to measure the uncertainty of prediction of Non-Gaussian process surrogates. To address this issue, this article proposes a method to measure the uncertainty. In this method, a stationary random field with a known zero mean is used to measure the uncertainty of prediction of Non-Gaussian process surrogates. Based on experimental analyses, this method is able to measure the uncertainty of prediction of Non-Gaussian process surrogates. The method's effectiveness is demonstrated on a set of benchmark problems in single surrogate and ensemble surrogates cases. [ABSTRACT FROM AUTHOR]

Carbon group nanofluids can further improve the friction-reducing and anti-wear properties of minimum quantity lubrication (MQL). However, the formation mechanism of lubrication films generated by carbon group nanofluids on MQL grinding interfaces is not fully revealed due to lack of sufficient evidence. Here, molecular dynamic simulations for the abrasive grain/workpiece interface were conducted under nanofluid MQL, MQL, and dry grinding conditions. Three kinds of carbon group nanoparticles, i.e., nanodiamond (ND), carbon nanotube (CNT), and graphene nanosheet (GN), were taken as representative specimens. The [BMIM]BF4 ionic liquid was used as base fluid. The materials used as workpiece and abrasive grain were the single-crystal Ni-Fe-Cr series of Ni-based alloy and single-crystal cubic boron nitride (CBN), respectively. Tangential grinding force was used to evaluate the lubrication performance under the grinding conditions. The abrasive grain/workpiece contact states under the different grinding conditions were compared to reveal the formation mechanism of the lubrication film. Investigations showed the formation of a boundary lubrication film on the abrasive grain/workpiece interface under the MQL condition, with the ionic liquid molecules absorbing in the groove-like fractures on the grain wear’s flat face. The boundary lubrication film underwent a friction-reducing effect by reducing the abrasive grain/workpiece contact area. Under the nanofluid MQL condition, the carbon group nanoparticles further enhanced the tribological performance of the MQL technique that had benefited from their corresponding tribological behaviors on the abrasive grain/workpiece interface. The behaviors involved the rolling effect of ND, the rolling and sliding effects of CNT, and the interlayer shear effect of GN. Compared with the findings under the MQL condition, the tangential grinding forces could be further reduced by 8.5%, 12.0%, and 14.1% under the diamond, CNT, and graphene nanofluid MQL conditions, respectively. [ABSTRACT FROM AUTHOR]

The substitution of biolubricant for mineral cutting fluids in aerospace material grinding is an inevitable development direction, under the requirements of the worldwide carbon emission strategy. However, serious tool wear and workpiece damage in difficult-to-machine material grinding challenges the availability of using biolubricants via minimum quantity lubrication. The primary cause for this condition is the unknown and complex influencing mechanisms of the biolubricant physicochemical properties on grindability. In this review, a comparative assessment of grindability is performed using titanium alloy, nickel-based alloy, and high-strength steel. Firstly, this work considers the physicochemical properties as the main factors, and the antifriction and heat dissipation behaviours of biolubricant in a high temperature and pressure interface are comprehensively analysed. Secondly, the comparative assessment of force, temperature, wheel wear and workpiece surface for titanium alloy, nickel-based alloy, and high-strength steel confirms that biolubricant is a potential replacement of traditional cutting fluids because of its improved lubrication and cooling performance. High-viscosity biolubricant and nano-enhancers with high thermal conductivity are recommended for titanium alloy to solve the burn puzzle of the workpiece. Biolubricant with high viscosity and high fatty acid saturation characteristics should be used to overcome the bottleneck of wheel wear and nickel-based alloy surface burn. The nano-enhancers with high hardness and spherical characteristics are better choices. Furthermore, a different option is available for high-strength steel grinding, which needs low-viscosity biolubricant to address the debris breaking difficulty and wheel clogging. Finally, the current challenges and potential methods are proposed to promote the application of biolubricant. [ABSTRACT FROM AUTHOR]

Bone grinding is an essential and vital procedure in most surgical operations. Currently, the insufficient cooling capacity of dry grinding, poor visibility of drip irrigation surgery area, and large grinding force leading to high grinding temperature are the technical bottlenecks of micro-grinding. A new micro-grinding process called ultrasonic vibration-assisted nanoparticle jet mist cooling (U-NJMC) is innovatively proposed to solve the technical problem. It combines the advantages of ultrasonic vibration (UV) and nanoparticle jet mist cooling (NJMC). Notwithstanding, the combined effect of multi parameter collaborative of U-NJMC on cooling has not been investigated. The grinding force, friction coefficient, specific grinding energy, and grinding temperature under dry, drip irrigation, UV, minimum quantity lubrication (MQL), NJMC, and U-NJMC micro-grinding were compared and analyzed. Results showed that the minimum normal grinding force and tangential grinding force of U-NJMC micro-grinding were 1.39 and 0.32 N, which were 75.1% and 82.9% less than those in dry grinding, respectively. The minimum friction coefficient and specific grinding energy were achieved using U-NJMC. Compared with dry, drip, UV, MQL, and NJMC grinding, the friction coefficient of U-NJMC was decreased by 31.3%, 17.0%, 19.0%, 9.8%, and 12.5%, respectively, and the specific grinding energy was decreased by 83.0%, 72.7%, 77.8%, 52.3%, and 64.7%, respectively. Compared with UV or NJMC alone, the grinding temperature of U-NJMC was decreased by 33.5% and 10.0%, respectively. These results showed that U-NJMC provides a novel approach for clinical surgical micro-grinding of biological bone. [ABSTRACT FROM AUTHOR]

This research addresses and analyzes the results of a six-sigma approach used to optimize the logistics costs of a pipe manufacturing company. Two mathematical models are developed for containers to control the company's logistics. The Mathematical Programming Language (MPL) software is used to generate and solve these models. The results verify that the proposed mathematical models result in the company's logistics improvement, especially in the DMAIC (define, measure, analyze, improve, and control) cycle by providing flexibility in choosing the most appropriate containers for logistics. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Drying via solar energy is an environmentally friendly and inexpensive process. For controlled and bulk level drying, a greenhouse solar dryer is the most suitable controlled level solar dryer. The efficiency of a solar greenhouse dryer can be increased by using thermal storage. The agricultural products dried in greenhouses are reported to be of a higher quality than those dried in the sun because they are shielded from dust, rain, insects, birds, and animals. The heat storage-based greenhouse was found to be superior for drying of all types of crops in comparison to a normal greenhouse dryer, as it provides constant heat throughout the drying process. Hence, this can be used in rural areas by farmers and small-scale industrialists, and with minor modifications, it can be used anywhere in the world. This article provides a comprehensive analysis of the development of solar greenhouse dryers for drying various agricultural products, including their design, thermal modelling methods, cost, energy, and environmental implications. Furthermore, the choice and application of solar photovoltaic panels and thermal energy storage units in the solar greenhouse dryers are examined in detail, with a view to achieving continuous and grid-independent drying. The energy requirements of various greenhouse dryer configurations/shapes are compared. Thermodynamic and thermal modelling research that reported on the performance prediction of solar greenhouse dryers, and drying kinetics studies on various agricultural products, has been compiled in this study. [ABSTRACT FROM AUTHOR]

Bone tissue engineering (BTE) is a promising alternative to repair bone defects using biomaterial scaffolds, cells, and growth factors to attain satisfactory outcomes. This review targets the fabrication of bone scaffolds, such as the conventional and electrohydrodynamic techniques, for the treatment of bone defects as an alternative to autograft, allograft, and xenograft sources. Additionally, the modern approaches to fabricating bone constructs by additive manufacturing, injection molding, microsphere-based sintering, and 4D printing techniques, providing a favorable environment for bone regeneration, function, and viability, are thoroughly discussed. The polymers used, fabrication methods, advantages, and limitations in bone tissue engineering application are also emphasized. This review also provides a future outlook regarding the potential of BTE as well as its possibilities in clinical trials. [ABSTRACT FROM AUTHOR]

Mold breakout is one of the significant problems in a continuous casting machine (caster). It represents one of the key areas within the steel production facilities of a steel plant. A breakout event on a caster will always cause safety hazards, high repair costs, loss of production, and shutdown of the caster for a short while. In this paper, a logic-judgment-based mold breakout prediction system has been developed for a continuous casting machine. This system developed new algorithms to detect the different sticker behaviors. With more algorithms running, each algorithm is more specialized in the other behaviors of stickers. This new logic-based breakout prediction system (BOPS) not only detects sticker breakouts but also detects breakouts that takes place due to variations in casting speed, mold level fluctuation, and taper/mold problems. This system also finds the exact location of the breakout in the mold and reduces the number of false alarms. The task of the system is to recognize a sticker and prevent a breakout. Moreover, the breakout prediction system uses an online thermal map of the mold for process visualization and assisting breakout prediction. This is done by alerting the operating staff or automatically reducing the cast speed according to the location of alarmed thermocouples, the type of steel, the tundish temperature, and the size of the cold slab width. By applying the proposed model in an actual steel plant, field application results show that it could timely detect all 13 breakouts with a detection ratio of 100%, and the frequency of false alarms was less than 0.056% times/heat. It has the additional advantage of not needing a lot of learning data, as most neural networks do. Thus, this new logical BOPS system should not only detect the sticker breakouts but also detect breakouts taking place due to variations in casting speed and mold level fluctuation. [ABSTRACT FROM AUTHOR]

Cutting tool characterization plays a crucial role in understanding the behavior of machining operations. The selection of a suitable cutting material, the operating conditions for the work piece, is necessary to yield good cutting-tool life. Several pieces of research have been carried out in cutting-tool characteristics for turning operation. Only a few pieces of research have focused on correlating the vibrations and stress with wear characteristics. This research article deals with stress induced in silicon carbide tool inserts and coated tool inserts while machining SS304 steel. Since this material is much less resistant to corrosion and oxidation it is widely used in engineering applications such as cryogenics, the food industry and liquid contact surfaces. Moreover, these materials have much lower magnetic permeability so they are used as nonmagnetic engineering components which are very hard. This article focuses on the machining of SS304 by carbide tool inserts and then, the cutting forces were observed with a tool dynamometer. Using observed cutting forces, the induced stress in the lathe tool insert was determined by FEA investigation. This research also formulates an idea to predict the tool wear due to vibration. Apparently, the worn-out tool vibrates more than new tools. Using the results, the relation between stress, strain and feed rate, depth of cut and speed was found and mathematically modeled using MINI TAB. It was observed that carbide tool inserts with coating withstand better than uncoated tools while machining SS304. The results were anticipated and correlation between the machining parameters furnished the prediction of tool life and obtaining the best machining outcomes by using coated tool inserts. [ABSTRACT FROM AUTHOR]

Temperature changes have significant effects on rock properties. The changes in properties vary for different rocks with different temperature ranges. Granite is an igneous type of rock that is common in India and is frequently used for construction and domestic purposes. Granite is mainly composed of quartz and feldspar and shows a considerable response to temperature changes and is the subject of this paper. A comprehensive review of the published literature has been conducted in this paper. Comparison of the findings of such works in terms of the impact of temperature changes on basic mechanical, physical, and thermal properties of granite, viz. thermal damage, density, p-wave velocity, compressive strength, peak stress, peak strain, and Young's modulus from room temperature to 1000 °C has been conducted. The published data of different researchers have been utilized for such comparison. The study revealed that there is a significant departure in response to the rock recorded by various researchers, which may be due to the constitution of the rocks analyzed or experimental procedures. This points to the standardization of such tests. The main reason for changes in the properties of granite has also been discussed. Consequently, the findings of this state-of-the-art demonstrate that the heating effects of granite on its physical and mechanical properties become increasingly pronounced with increasing pick temperatures. The purpose of this article is to provide readers with an extremely well-structured, seamless environment that facilitates a critical assessment of granite in order to determine its thermal profile. [ABSTRACT FROM AUTHOR]

The impact of single-slope solar still with and without flat-plate collector was evaluated experimentally and numerically. Experimental analysis was conducted for four different water depths (3, 6, 9, 12 cm) in on-sunshine hours between 11 AM to 5 PM in Bhopal (23.2599° N, 77.4126° E), India. The thermo efficiency was 51.31% for 3 cm water depth while 24.29% for 12 cm water depth in an active mode of operation. In the case of passive mode, the thermo efficiency was 17.02% for 3 cm water depth and 6.77% for 12 cm water depth. The average exergy efficiency of single-slope solar still is 66.60% for 3 cm depth which is higher than 12 cm depth, i.e., 23.14%. The hourly variation parameters of solar still were also calculated and analyzed. The overall results obtained in the analysis state that solar still performs effectively when coupled with a flat-plate solar collector. According to econometric evaluation, the fabrication expense of a single-slope solar-basin-still is 126.43$ whereas the cost of producing distilled water per day is 1.61$, and the payback period of a single-slope solar-basin-still with FPC is 17.53 months. In a nutshell, the single-slope solar-basin-still design is commercially viable, functional, and technically sustainable, minimizing manufacturing costs in comparison with a traditional solar still, and past findings. The proposed solar still produced remarkable results in all experimental trials. [ABSTRACT FROM AUTHOR]

Increasing global environmental problems and awareness towards the utilization of eco-friendly resources enhanced the progress of research towards the development of next-generation biodegradable and environmentally friendly material. The development of natural-based composite material has led to various advantages such as a reduction in greenhouse gases and carbon footprints. In spite of the various advantages obtained from green materials, there are also a few disadvantages, such as poor interfacial compatibility between the polymer matrix and natural reinforcements and the high hydrophilicity of composites due to the reinforcement of hydrophilic natural fibers. This review focuses on various moisture-absorbing and sound-absorbing natural fiber polymer composites along with the synopsis of preparation methods of natural fiber polymer composites. It was stated in various studies that natural fibers are durable with a long life but their moisture absorption behavior depends on various factors. Such natural fibers possess different moisture absorption behavior rates and different moisture absorption behavior. The conversion of hydrophilic fibers into hydrophobic is deemed very important in improving the mechanical, thermal, and physical properties of the natural-fiber-reinforced polymer composites. One more physical property that requires the involvement of natural fibers in place of synthetic fibers is the sound absorption behavior. Various researchers have made experiments using natural-fiber-reinforced polymer composites as sound-absorbing materials. It was found from various studies that composites with higher thickness, porosity, and density behaved as better sound-absorbing materials. [ABSTRACT FROM AUTHOR]

Surface mining is the world's most costly industry due to its enormous expenses. Reduced production is forcing mining companies to automate their equipment, predominantly heavy earth mining machinery (HEMMs), for example, dump trucks, shovels, and dozers. The backbone of pit mining is the crawler dozer, commonly known as a dozer. Crawler dozers are tracked earth-moving machines with metal blades positioned in front for pushing materials such as rocks, soil, etc. In order to survive the harsh competition, dozers must be durable and adequately maintained. Crawler dozers work under challenging conditions to avoid production delays that result in losses such as breakdowns, transmission failures, and other issues in mining operations. Transmission failures, among other issues with dozers, are one of the hardest to resolve. This study evaluates the reliability, availability, and maintainability (RAM) of a BD155 crawler dozer transmission using failure and repair data and the Markov method. A realistic case study on (BD155) transmission failure and associated subsystems has been performed. Potential approaches and alternatives are also identified to increase dependability and performance. This article also discusses best maintenance practices for minimizing transmission failures and boosting productivity. The availability of the BD155 increases to 71% from 62% using proper planning and maintenance. [ABSTRACT FROM AUTHOR]

Earthen materials are the world's oldest and cheapest construction materials. Compacted soil stabilised blocks are unfired admixed soil blocks made up of soil plus stabilisers such as binders, fibres, or a combination of both. The manufacturing and usage of cement and cement blocks raises a number of environmental and economic challenges. As a result, researchers are attempting to develop an alternative to cement blocks, and various tests on unfired admixed soil blocks have been performed. This investigation undertakes use of agricultural waste (i.e., paddy straw fiber and sugarcane bagasse ash) and industrial waste (i.e., marble dust) in manufacturing unfired admixed soil blocks. The applicability of unfired soil blocks admixed with marble dust, paddy straw fiber, and bagasse ash were studied. The marble dust level ranged from 25% to 35%, the bagasse ash content ranged from 7.5% to 12.5%, and the content of paddy straw fibre ranged from 0.8% to 1.2% by soil dry weight. Various tests were conducted on 81 mix designs of the prepared unfired admixed soil blocks to determine the mechanical properties of the blocks, followed by modeling and optimization. The characterization of the materials using XRD and XRF and of the specimens using SEM and EDS were performed for the mineral constituents and microstructural analysis. The findings demonstrate that the suggested method is a superior alternative to burned bricks for improving the mechanical properties of unfired admixed soil blocks. [ABSTRACT FROM AUTHOR]

Waste management is the first priority for many countries, so the focus of this research is on using waste materials in concrete as fillers and substituting concrete ingredients such as crumb rubber (CR) for fine aggregates. The utilization of waste rubber in concrete has gained attention recently, but CR substitution results in a reduction in mechanical and durability properties due to weak bonding and lower stiffness of CR. To overcome this issue, the addition of strength-increasing waste materials as cement substitutes is investigated along with CR (5%, 10%, and 15%) as fine aggregates and tested for the mechanical and durability behavior of concrete. Constant 10% waste glass powder (WGP) and 10% silica fume (SF) were substituted with cement in separate mixes. The main goal of this study is to investigate the suitable proportion of the materials from SF and WGP for enhancing rubberized concrete's properties and to evaluate waste materials' uses considering various parameters. The concrete is compared for both materials used as well as with control concrete and CR concrete for properties such as workability, compressive strength, tensile strength, density, ultrasonic pulse velocity, and dynamic modulus of elasticity. The reduction in compressive strength, tensile strength, workability, density, ultrasonic pulse velocity, and dynamic modulus of elasticity was observed due to the incorporation of CR, but also an increase in these properties with the incorporation of silica fumes (SF) and waste glass powder (WGP) as cement. It was observed that SF enhanced the properties of rubberized concrete better as compared to WGP. The 10% SF with 5% CR enhanced the compressive strength of rubberized concrete without SF by 11%. Similarly, 10% of WGP with 5% of CR enhanced the compressive strength of rubberized concrete by 6%. [ABSTRACT FROM AUTHOR]

Conventional twist drills have problems such as large axial force, severe delamination, high temperature, and serious surface quality damage when drilling Al2024-T351/Ti-6Al-4V laminated materials. The main reason is that the low cutting performance of the drill bit in the conventional drilling (CD) process requires a higher axial force, and it also makes the drill bit wear serious. In order to solve these problems, special geometric tools are usually used for drilling and ultrasonic assisted drilling is added. This paper focuses on conventional drilling (CD) and ultrasonic-assisted drilling (UAD) drilling of multipoint drilling tools. The biggest difference between UAD and CD is that it exerts a certain frequency and amplitude vibration on the drill bit, which can make the drill bit go down with periodic axial vibration. Since the drilling motion curve is microscopically a sine curve, the breaking and removal of chips are accelerated during the drilling process, which is beneficial to improve the machining accuracy. Under the ideal experimental conditions, the drilling of laminated materials was explored through a combination of experiment and simulation. Experiments show that the use of geometric tools can improve the defects caused by twist drill processing, while the use of UAD can further improve the problems of large axial force, serious delamination, high temperature and serious surface quality damage. The tool wear is reduced and the hole surface accuracy is improved. [ABSTRACT FROM AUTHOR]

In the construction of steel structures, the two most common types of structural members are hot-formed and cold-formed members. This paper mainly describes the analytical and experimental research on the strength and characteristics of CFS bolted built-up sigma sections having different structural arrangements under bending. The cross-sectional dimensions for the parametric study were selected by the sizes available in the market. In this paper, ANSYS workbench software was used to perform FE modeling and observe the local, flexural, and interaction of these buckling. Then, experimental study was performed by varying the arrangement of open section beams between face-to-face and back-to-back, connected using bolts or fasteners different spacings. Further, we conducted bending tests on cold-formed steel built-up members having simple edge stiffeners in the middle. Comparing both analytical and experimental studies, the results indicate that the back-to-back connected built-up beam section provides a flexural capacity higher than the face-to-face built-up section. Moreover, increasing the bolt spacing enhanced the load-carrying capacity of back-to-back sigma section built-up beams. It has also been discovered that the flexural strength of beams is primarily determined by bolt spacing or itsposition. [ABSTRACT FROM AUTHOR]

Friction stir spot welding (FSSW) is one of the most popular fusion joining processes. The process is a solid-state welding process that allows welding of weldable as well as non-weldable materials. As a part of this investigation, weld samples of Al6061-T6 were reinforced with silicon carbide (SiC) powder with an average particle size of 45 µm. Initially, a Taguchi L9 orthogonal array was developed with three factors, i.e., rotational speed of the tool, pre-dwelling time, and diameter of the hole that was filled with SiC before welding. The effects of the SiC particles and process parameters were investigated as tensile–shear load and micro-hardness. The optimisation of parameters in order to maximise the output responses—i.e., strength and hardness of the welded joints—was performed using a hybrid WASPAS–Taguchi method. The optimised process parameters obtained were a 3.5 mm guiding hole diameter, 1700 rpm tool rotation speed, and 14 s of pre-dwelling time. [ABSTRACT FROM AUTHOR]