Search results for "roughness"
showing 6 items of 216 documents
MATHEMATICAL MODELLING OF SURFACE ROUGHNESS FOR EVALUATING THE EFFECTS OF WEDM CUTTING PARAMETERS
2020
Wire Electrical Discharge Machining is a cutting method used for obtaining parts with complex geometries or for cutting hard metals. In machining processes, it is necessary to obtain the desired surface quality in order to produce parts providing the required functioning. The surface quality also defines some mechanical properties of the product, such as wear resistance. Being such a considerable quality, surface quality is influenced by various parameters. It will be costly and time consuming to acquire the knowledge of appropriate cutting parameters. Unconventional technologies have not been sufficiently studied so far to provide such details. So, this рарer ѕeekѕ to emрhаѕіze the іmрortа…
Surface Topographies of Glaucoma Drainage Devices and Their Influence on Human Tenon Fibroblast Adhesion
2010
PURPOSE. This study was performed to investigate the surface topography of different glaucoma drainage devices and to determine the effects of surface roughness on cell adhesion of cultured human tenon fibroblasts.METHODS. The surface topography of four widely used devices (Ahmed FP7 and Ahmed S-2; New World Medical, Inc., Rancho Cucamonga, CA; Baerveldt BG101-350; Advanced Medical Optics, Irvine, CA; and Molteno S1; Molteno Ophthalmic Ltd., Dunedin, New Zealand) was investigated by scanning electron microscopy, and roughness was quantified by white-light confocal microscopy. Cells were grown for 72 hours on the surfaces of implants affixed to standard culture dishes. The cells were labeled…
Characterization of thin plastic foils for applications in X-ray optics technology
2007
Thin plastic foils are being investigated to build shell optics for X-ray telescopes. Compared to polished glass optics, the advantage is in terms of increased collecting area, light weight and lower cost. Plastic material is also desirable to allow deformation into a complete surface of revolution. We collected plastic materials of common use for industrial applications and also specialty materials developed for the electronic industry. A comparative study was then performed to evaluate the optical quality of the selected plastic films. Surface analysis was carried out with topographic instruments to investigate the microroughness of our samples at different scan lengths. Preliminary resul…
Stress sensitivity of stylolite morphology
2009
International audience; Stylolites are rough surfaces that form by localized stress-induced dissolution. Using a set of limestone rock samples collected at different depths from a vertical section in Cirque de Navacelles (France), we study the influence of the lithostatic stress on the stylolites morphology on the basis of a recent morphogenesis model. We measured the roughness of a series of bedding-parallel stylolites and show that their morphology exhibits a scaling invariance with two self-affine scaling regimes separated by a crossover-length (L) at the millimeter scale consistent with previous studies. The importance of the present contribution is to estimate the stylolite formation s…
Numerical Simulations of the Flow Field of a Submerged Hydraulic Jump over Triangular Macroroughnesses
2021
The submerged hydraulic jump is a sudden change from the supercritical to subcritical flow, specified by strong turbulence, air entrainment and energy loss. Despite recent studies, hydraulic jump characteristics in smooth and rough beds, the turbulence, the mean velocity and the flow patterns in the cavity region of a submerged hydraulic jump in the rough beds, especially in the case of triangular macroroughnesses, are not completely understood. The objective of this paper was to numerically investigate via the FLOW-3D model the effects of triangular macroroughnesses on the characteristics of submerged jump, including the longitudinal profile of streamlines, flow patterns in the cavity regi…
Etude en champ proche et champ lointain de surfaces métalliques : apport des microscopies à sonde locale à l'étude des étalons de masse
2005
Among the international system of units (SI) the kilogram is the only one which is still defined by a material artefact, the international prototype of the platinum iridium kilogram. The instability of mass standards is one of the major concerns of national metrology institutes and the subject of numerous studies. Interest in microscopic studies of surface quality of a mass has grown, as it is well known that surface roughness is a factor in determining the long-term stability of mass standards. This thesis is devoted to the study in near field and far field for determining the topography and roughness of metallic surfaces, in related with different institute, national and international met…