Frequency: Quarterly E- ISSN: 2277-8284 P- ISSN: Awaited Abstracted/ Indexed in: CNKI Scholar (China National Knowledge Infrastructure), Ulrichâ??s International Periodical Directory, Google Scholar, SCIRUS, getCITED, Genamics JournalSeek
Tribology, the science of rubbing surfaces, is involved at micro and macro level in several aspects of life and technology. A finer understanding of this is becoming essential as the things are getting smaller, or where nano or bionic designs are involved; besides the domain of regular size or mega machines. â??Inventi Rapid/Impact: Tribologyâ?? is a multidisciplinary journal and aims to engage the researchers not only from engineering and technology, but from the life sciences as well.
When aluminum or its alloys are melted, considerable amounts of dross are produced. The alloy type and the method used in the production of aluminum products play an important role in the amount of dross that will result as a byproduct. The current needs of the Al industry as well as economic and environmental factors demand the recovery of the pure material that is lost during dross removal by simple and efficient methods that can be applied within the foundry. Most cases of Al recovery employ methods of dross compression at high temperatures. This investigation attempts to develop a mathematical model to characterize the efficiency of the recovery process that can be implemented for any dross collection method or even compression device, facilitating the direct comparison of recovery methods....
We have developed a novel instrument combining a glide tester with anAtomic ForceMicroscope (AFM) for hard disk drive (HDD)\r\nmedia defect test and analysis. The sample stays on the same test spindle during both glide test and AFM imaging without losing\r\nthe relevant coordinates. This enables an in situ evaluation with the high-resolution AFM of the defects detected by the glide test.\r\nThe ability for the immediate follow-on AFM analysis solves the problem of relocating the defects quickly and accurately in the\r\ncurrent workflow. The tool is furnished with other functions such as scribing, optical imaging, and head burnishing. Typical data\r\ngenerated from the tool are shown at the end of the paper. It is further demonstrated that novel experiments can be carried out on\r\nthe platform by taking advantage of the correlative capabilities of the tool....
The challenges in designing future head disk interface (HDI) demand efficient theoretical modeling tools with flexibility in\r\ninvestigating various combinations of perfluoropolyether (PFPE) and carbon overcoat (COC) materials. For broad range of time\r\nand length scales, we developedmultiscale/multiphysical modeling approach, which can bring paradigm-shifting improvements in\r\nadvanced HDI design. In this paper, we introduce our multiscale modeling methodology with an effective strategic framework for\r\nthe HDI system. Our multiscale methodology in this paper adopts a bottom to top approach beginning with the high-resolution\r\nmodeling, which describes the intramolecular/intermolecular PFPE-COC degrees of freedomgoverning the functional oligomeric\r\nmolecular conformations on the carbon surfaces. By introducing methodology for integrating atomistic/molecular/mesoscale levels\r\nvia coarse-graining procedures, we investigated static and dynamic properties of PFPE-COC combinations with variousmolecular\r\narchitectures. By bridging the atomistic and molecular scales, we are able to systematically incorporate first-principle physics into\r\nmolecular models, thereby demonstrating a pathway for designing materials based on molecular architecture. We also discussed\r\nfuture materials (e.g., graphene for COC, star-like PFPEs) and systems (e.g., heat-assisted magnetic recording (HAMR)) with\r\nhigher scale modeling methodology, which enables the incorporation of molecular/mesoscale information into the continuum\r\nscale models....
Airborne particulate emissions originating from the wear of pads and rotors of disc brakes contribute up to 50% of the total road\nemissions in Europe. The wear process that takes place on a mesoscopic length scale in the contact interfaces between the pads\nand rotors can be explained by the creation and destruction of contact plateaus. Due to this complex contact situation, it is hard to\npredict how changes in the wear and material parameters of the pad friction material will affect the friction and wear emissions.\nThis paper reports on an investigation of the effect of different parameters of the pad friction material on the coefficient of friction\nand wear emissions. A full factorial design is developed using a simplified version of a previously developed cellular automaton\napproach to investigate the effect of four factors on the coefficient of friction and wear emission. The simulated result indicates\nthat a stable third body, a high specific wear, and a relatively high amount of metal fibres yield a high and stable mean coefficient\nof friction, while a stable third body, a low specific wear, a stable resin, and a relatively high amount of metal fibres give low wear\nemissions....
When an elastic body of revolution rolls tractively over another, the period from commencement of rolling until gross rolling\r\nensues is termed the prerolling regime. The resultant tractions in this regime are characterized by rate-independent hysteresis behavior\r\nwith nonlocal memory in function of the traversed displacement. This paper is dedicated to the theoretical characterization\r\nof traction during prerolling. Firstly, a theory is developed to calculate the traction field during prerolling in function of the instantaneous\r\nrolling displacement, the imposed longitudinal, lateral and spin creepages, and the elastic contact parameters. Secondly,\r\nthe theory is implemented in a numerical scheme to calculate the resulting traction forces and moments on the tractive rolling of a\r\nball. Thirdly, the basic hysteresis characteristics are systematically established by means of influence-parameters simulations using\r\ndimensionless forms of the problem parameters. The results obtained are consistent with the limiting cases available in literature\r\nand they confirm experimental prerolling hysteresis observations. Furthermore, in a second paper, this theory is validated experimentally\r\nfor the case of V-grooved track....
According to the performance degradation problem of feature extraction from higher-order statistics in the context of alphastable\nnoise, a new feature extraction method is proposed. Firstly, the nonstationary vibration signal of rolling bearings is\ndecomposed into several product functions by LMD to realize signal stability. ,en, the distribution properties of product\nfunctions in the time domain are discussed by the comparison of heavy tails and characteristic exponent estimation. Fractional\nlower-order p-function optimization is obtained by the calculation of the distance ratio based on K-means algorithms. Finally, a\nfault feature dataset is established by the optimal FLOS and lower-dimensional mapping matrix of covariation to accurately and\nintuitively describe various bearing faults. Since the alpha-stable noise is effectively suppressed and state described precisely, the\npresented method has shown better performance than the traditional methods in bearing experiments via fractional lower-order\nfeature extraction....
To improve the efficiency of geared transmissions, prediction models are required. Literature provides only simplified models\nthat often do not take into account the influence of many parameters on the power losses. Recently some works based on CFD\nsimulations have been presented. The drawback of this technique is the time demand needed for the computation. In this work\na less time-consuming numerical calculation method based on some specific mesh-handling techniques was extensively applied.\nWith this approach the windage phenomena were simulated and compared with experimental data in terms of power loss. The\ncomparison shows the capability of the numerical approach to capture the phenomena that can be observed experimentally. The\npowerful capabilities of this approach in terms of both prediction accuracy and computational effort efficiency make it a potential\ntool for an advanced design of gearboxes as well as a powerful tool for further comprehension of the physics behind the gearbox\nlubrication....
A novel method which is a combination of wavelet packet transform (WPT),\r\nuninformative variable elimination by partial least squares (UVE-PLS) and simulated\r\nannealing (SA) to extract best variance information among different varieties of lubricants\r\nis presented. A total of 180 samples (60 for each variety) were characterized on the basis of\r\nvisible and short-wave infrared spectroscopy (VIS-SWNIR), and 90 samples (30 for each\r\nvariety) were randomly selected for the calibration set, whereas, the remaining 90 samples\r\n(30 for each variety) were used for the validation set. The spectral data was split into\r\ndifferent frequency bands by WPT, and different frequency bands were obtained. SA was\r\nemployed to look for the best variance band (BVB) among different varieties of lubricants.\r\nIn order to improve prediction precision further, BVB was processed by UVE-PLS and the\r\noptimal cutoff threshold of UVE was found by SA. Finally, five variables were mined, and\r\nwere set as inputs for a least square-support vector machine (LS-SVM) to build the\r\nrecognition model. An optimal model with a correlation coefficient (R) of 0.9850 and root\r\nmean square error of prediction (RMSEP) of 0.0827 was obtained. The overall results\r\nindicated that the method of combining WPT, UVE-PLS and SA was a powerful way to\r\nselect diagnostic information for discrimination among different varieties of lubricating oil,\r\nfurthermore, a more parsimonious and efficient LS-SVM model could be obtained...
An important parameter in the reduction of fuel consumption of heavy-duty diesel engines is the Power Cylinder Unit (PCU); the\nPCU is the single largest contributor to engine frictional losses.Much attention, fromboth academia and industry, has been paid to\nreducing the frictional losses of the PCU in the boundary and mixed lubrication regime.However, previous studies have shown that\na large portion of frictional losses in the PCU occur in the hydrodynamic lubrication regime. A novel texturing design with large\ntypes of surface features was experimentally analyzed using a tribometer setup.Theexperimental result shows a significant reduction\nof friction loss for the textured surfaces. Additionally, the textured surface did not exhibit wear. On the contrary, it was shown that\nthe textured surfaces exhibited a smaller amount of abrasive scratches on the plateaus (compared to the reference plateau honed\nsurface) due to entrapment of wear particles within the textures. The decrease in hydrodynamic friction for the textured surfaces\nrelates to the relative increase of oil film thickness within the textures. A tentative example is given which describes a method of\ndecreasing hydrodynamic frictional losses in the full-scale application....
Anovel ceramic composite inward gradient distribution layer has been developed.Thelayer is a lubricating layer inwhich soft-metal\nlubricants are compounded into the ceramic matrix by high frequency induction infiltrating method. The design of the layer and its\nlubricating mechanism are investigated in the paper. The results show that the property of the layer greatly depends on the wetting\nangle of the soft-metal lubricants on the matrix and the proportion of Ag, Cu, Sn, and Pb as well as the infiltrating parameters.\nBased on a lot of experiments, a novel inward gradient layer with Pb28Sn19Ag6Cu has been developed. The layer has an excellent\nlubricating property (friction coefficient about 0.2âË?¼0.3 at 600âË?Ë?C). The research reveals the lubricating mechanism, observing the\nphenomenon that the soft-metal in the matrix diffuses out of the frictional surface, and measures the lubricating film thickness as\nabout 20 ...
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