Recently, herringbone-grooved journal bearings (HGJBs) have important applications in high-speed rotating machinery. The groove action in pumping the lubricating fluid inward generates supporting stiffness and improves the stability of the bearing when operating concentrically. Several researchers have investigated the static and dynamic characteristics of HGJBs and grooved thrust bearings. Most of these investigations were theoretical and concentrated on HGJBs with rectangular-profile grooves. In the present work, the static and dynamic characteristics of the beveled-step HGJBs are experimentally investigated. The bearing attitude angle, pressure distribution, and bearing friction torque were measured on a hydrodynamic lubrication unit, and then the static and dynamic characteristics were determined. The obtained experimental results are compared to the obtained experimental results for plain journal bearing. The merits as well as the demerits of the groove profile were discussed through comparisons with plain journal bearings.
DOI: 10.1115/1.2908903

Reduction of the thermal stresses in machine elements that are subjected to severe thermal loadings was achieved by developing two-dimensional functionally graded materials, 2D-FGM. In the current investigation, composition optimization for ZrO2/6061-T6/Ti-6Al-4V 2D-FGM, under a severe thermal loading cycle that consists of heating followed by cooling, was carried out based on the minimization of temperatures and thermal and residual stresses to achieve better reduction of the thermal stresses. From the current investigation it was found that the optimum composition based on the minimum value of the maximum temperature for ZrO2/6061-T6/Ti-6Al-4V 2D-FGMwas achieved formx = 0.1 andmy = 0.1, while the optimum composition based on the minimum value of the maximum normalized equivalent stresses for ZrO2/6061-T6/Ti-6Al-4V 2D-FGM was achieved for mx = 0.1 and my = 5, where mx and my are the composition variation parameters in x- and y-directions, respectively. Also, the obtained optimum composition of ZrO2/6061-T6/Ti-6Al-4V 2D-FGM can stand well with the adopted severe thermal loading without any plastic deformation or residual stresses, where the maximum value of the normalized equivalent stresses during the heating stage was 0.8 and the maximum value of the normalized equivalent stresses during the cooling stage was 0.24.

This paper introduces a new formula for the objective function of the famous fuzzy C-means algorithm. Two weighted terms are added to the objective function to reflect any available information about the class center and class pixels distribution throughout the datasets. The algorithm is evaluated for the task of the segmentation of medical MRI brain volume. The results show that the algorithm has a considerable robustness against noise and partial volume effects, and it needs a smaller number of iterations to reach convergence compared with other similar algorithms.

This paper presents an image processing-based approach for the assessment of living cell apoptosis. The approach uses deformable models in tracing the changes in cell shapes in accordance to possible apoptotic cell death. Stochastic controlled energy function is used to drive the evolution of the deformable model. As an application for the proposed approach, it is applied for detecting the morphological changes in exercise-induced immune cells during their apoptosis. The approach is used with the goal of automating the assessment of cell apoptosis. The proposed approach shows promising results in detecting these morphological changes.