An outlier correction procedure for areal surface topography data based on surrounding data for outlier detection and correction is reviewed. The outlier detection is based on the median relative height of the surrounding data within a defined detection window. The threshold value is calculated from a cumulative probability curve of the medians of all data points. The detection window size is selected based on the size of the largest outlier cluster observed on the topography data. The application of the procedure to dental implant surface topography data measured by a confocal laser scanning microscope shows excellent outlier removal compared to typical filtering methods. The procedure only affects outliers, and the information on normal data points remains unchanged. The application to topography data from 21 repeated measurements of a deterministic measuring standard shows great improvement in accuracy and repeatability of surface roughness parameters. The flexibility of the outlier correction procedure is observed through its application to several types of topography data from various types of optical surface measurement systems.
Purpose
This study aims to investigate the effect of different volume percentage (Vol.%) of steel fibre on the pressure, surface temperature and speed sensitivity behaviour during braking process as known brake effectiveness and to propose the best steel fibre Vol.% in the formulation.
Design/methodology/approach
Three brake pads composed of three different steel fibre volume percentages were fabricated through powder metallurgy route. Selecting one sample as based formulations, steel fibre (Vol.%) was decreased and increased by 50 per cent in the other two samples, respectively. The other ingredients are proportionally increased and decreased accordingly to the base formulation. The samples were tested for determining their hardness, porosity and coefficient of friction (COF) using Rockwell hardness tester, hot bath and brake inertia dynamometer, respectively.
Findings
Test results indicated that Sample T1 which composed of 9 Vol.% of steel fibre had the lowest COF and was sensitive to applied pressure, surface temperature and speed. The samples which composed of 18 and 27 Vol.% of steel fibre were having the same trend of COF and were sensitive to surface temperature and speed. Sample T which composed of 18 Vol.% of steel fibre had lower brake pad and disc lost as compared to Sample T2 which composed of 27 Vol.%. Mechanical properties did not show any significant correlation with COF sensitivity with temperature, speed and pressure.
Originality/value
The sample with 18 Vol.% of steel fibre was found to be the best formulation which produced acceptable COF; less sensitive to temperature, pressure and speed during braking process; and better wear resistance of brake pad as well as the rotor.
Cutting edges protrusion properties for cutting tools have significant effect of grinding surface finish and its characterization is crucial in understanding tool-work interaction. Existing definition of reference datum in surface topography analysis is not suitable for abrasive tool cutting edges protrusion characterization in relation to tool-work interaction. This paper proposed Surface Reversal Method for the reference datum determination in the characterization of cutting edge protrusion on flat end face of cylindrical cutting tool meant for vertical grinding. Fabricated cylindrical artefact is used to test the theory, accompanied with a specially made fixture. Performance of the proposed method is evaluated based on the repeatability of step height measurement on the topography component and inclination of the reference datum which extracted from primary surface measured by laser confocal scanning microscope. The proposed method provides better datum definition than conventional method for height measurement of the abrasive tool topography in relation to the tool-work interaction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.