Nano-enhanced biolubricant in sustainable manufacturing: From processability to mechanisms

Abstract

To eliminate the negative effect of traditional metal-working fluids and achieve sustainable manufacturing, the usage of nano-enhanced biolubricant (NEBL) is widely researched in minimum quantify lubrication (MQL) machining. It’s improved tool wear and surface integrity have been preliminarily verified by experimental studies. The previous review papers also concluded the major influencing factors of processability including nano-enhancer and lubricant types, NEBL concentration, micro droplet size, and so on. Nevertheless, the complex action of NEBL, from preparation, atomization, infiltration to heat transfer and anti-friction, is indistinct which limits preparation of process specifications and popularity in factories. Especially in the complex machining process, in-depth understanding is difficult and meaningful. To fill this gap, this paper concentrates on the comprehensive quantitative assessment of processability based on tribological, thermal, and machined surface quality aspects for NEBL application in turning, milling, and grinding. Then it attempts to answer mechanisms systematically considering multi-factor influence of molecular structure, physicochemical properties, concentration, and dispersion. Firstly, this paper reveals advanced lubrication and heat transfer mechanisms of NEBL by quantitative comparison with biolubricant-based MQL machining. Secondly, the distinctive filmformation, atomization, and infiltration mechanisms of NEBL, as distinguished from metal-working fluid, are clarified combining with its unique molecular structure and physical properties. Furtherly, the process optimization strategy is concluded based on the synergistic relationship analysis among process variables, physicochemical properties, machining mechanisms, and performance of NEBL. Finally, the future development directions are put forward aiming at current performance limitations of NEBL, which requires improvement on preparation and jet methods respects. This paper will help scientists deeply understand effective mechanism, formulate process specifications, and find future development trend of this technology.

The effects of heteroatom substituents on structure, stability, and electronic properties of remote N‐heterocyclic germylenes (rNHGes), at DFT

“…Following previous reports on cyclic divalent species, [20][21][22][23][24][25][26][27][28] organic compounds and nanostructures, [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] now we compare and contrast new rNHGes (1-10) by fusion of one benzene, pyrrole, phosphole, furan and thiophene ring in "orthoor zigzag" arrangement and "paraor chair" arrangement to 1H-4-germapyridine-4-ylidene (1) as the reference germylene.…”

Presentation of Machine Learning Approaches for Predicting the Severity of Accidents to Propose the Safety Solutions on Rural Roads

“…Various data collection methods can be incorporated into the proposed approach to obtain more variables [108,109]. In addition, for future studies, it is recommended to utilize other kinds of cross-validation techniques [110,111], machine learning methods [112][113][114][115][116][117][118][119], and optimization algorithms [120][121][122][123][124] to make a better decision about the interference of nonmotorized users and vehicle flow within a city and to develop models with high prediction accuracy in taking preventive measures for decreasing pedestrian accidents in urban environments. Also, various crash modeling and before-after safety evaluation methods can be incorporated into the proposed approaches to examine risk factors on crash rates [125][126][127][128].…”

Fiber-reinforced composites in milling and grinding: machining bottlenecks and advanced strategies

“…To further improve the heat transfer capacity and tribological characteristics of MQL, some scholars have proposed a new clean cooling and lubrication technology with low carbon, low consumption, and high efficiency nanofluid MQL (NMQL) [192][193][194]. The technical approach aims to add one or several nanoparticles with different physical and chemical properties to MQL base oil and fully disperse and mix the nanoparticles to prepare nanofluid [195][196][197][198]. Then, under the action of highpressure air flow, the nanofluid is atomized and sprayed into the cutting area through the nozzle [199,200].…”