three-dimensional surface geometry of rock discontinuities and its evolution with shearing are of great importance in understanding the deformability and hydro-mechanical behavior of rock masses. in the present research, surfaces of three natural rock fractures were digitized and studied before and after the direct shear test. the variography analysis of the surfaces indicated a strong non-line...

in this paper a novel numerical approach is presented for solving the transient incompressible fluid flow problems with free surfaces in generalized two-dimensional curvilinear coordinate systems. solution algorithm is a combination of implicit real-time steps and explicit pseudo-time steps. governing fluid flow equations are discretized using a collocated finite-volume mesh. convective terms a...

analysis of food surfaces is of interest because many processes depend on their complexity. food surfaces show several textural characteristics related to their nature, composition and processing. food surface images and their microscopic details need to be translated into numerical data before engineering analysis. fractal geometry is a novel concept to describe the complexity of natural shape...

the evaporation of liquid droplets is of fundamental importance in a large number of practical situations ranging from technological applications such as ink-jet printing, spray cooling and various coating processes, to a variety of biological and geophysical contexts. in this study, the behavior of the surfaces of glass, plexiglas, aluminum and copper in the evaporation of water droplets is st...

in this paper, a two-surfaces sliding mode controller (tssmc) is proposed for the voltage tracking control of a two input dc-dc converter in application of electric vehicles (evs). the imperialist competitive algorithm (ica) is used for tuning tssmc parameters. the proposed controller significantly improves the transient response and disturbance rejection of the two input converters while prese...

I. The existence of differences and similarities in the sur- 4. face features not only of different organisms or groups but also within given species has been demonstrated by a variety of techniques. 2. The different reactions of various organisms to the Gram stain might well be taken as one piece of evidence, the use of the electron microscop and associated prepa­rative techniques (includi...

We investigate surfaces with constant harmonic-mean curvature one (HMC-1 surfaces) in hyperbolic three-space. We allow them to have certain kinds of singularities, and discuss some global properties. As well as flat surfaces and surfaces with constant mean curvature one (CMC-1 surfaces), HMC-1 surfaces belong to a certain class of Weingarten surfaces. From the viewpoint of parallel surfaces, CM...

background and aims. the aim of this study was to evaluate the effect of different etching times on enamel color stability after immediate versus delayed exposure to colored artificial saliva (cas). materials and methods. human first premolars were divided into five groups of twenty. a colorimeter was used according to the cie system on the mid-buccal and mid-lingual surfaces to evaluate initia...

background and aims. previous researches, conducted mostly on extracted teeth, have shown that efficacy of calculus removal decreases with increasing pocket depth, but there is still a lack of clinical studies concerning the correlation be-tween residual calculus and varying pocket depths. the objective of the present clinical study was to assess the efficiency of mechanical tooth depuration by...