Effect Of Surface Profile Research Articles

Effects of surface profile on porcine dural mechanical properties

BackgroundCerebrospinal fluid leakage through the spinal meninges is difficult to diagnose and treat. Moreover, its underlying mechanism remains unknown. Considering that the dura mater is structurally the strongest and outermost membrane among the three-layered meninges, we hypothesized that a dural mechanical tear would trigger spontaneous cerebrospinal fluid leakage, especially when a traumatic loading event is involved. Thus, accurate biomechanical properties of the dura mater are indispensable for improving computational models, which aid in predicting blunt impact injuries and creating artificial substitutes for transplantation and surgical training. MethodWe characterized the surface profile of the spinal dura and its mechanical properties (Young's moduli) with a distinction of its inherent anatomical sites (i.e., the cervical and lumbar regions as well as the dorsal and ventral sides of the spinal cord). FindingsAlthough the obtained Young's moduli exhibited no considerable difference between the aforementioned anatomical sites, our results suggested that the wrinkles structurally formed along the longitudinal direction would relieve stress concentration on the dural surface under in vivo and supraphysiological conditions, enabling mechanical protection of the dural tissue from a blunt impact force that was externally applied to the spine. InterpretationThis study provides fundamental data that can be used for accurately predicting cerebrospinal fluid leakage due to blunt impact trauma.

An Experimental Study on the Shear Performance of Fully Encapsulated Cable Bolts in Single Shear Test

A set of single shear tests on fully encapsulated cable bolts was carried out using a newly developed and integrated Megabolt single shear apparatus. The instrument is designed to determine the pure shear strength of cable bolts where there is no contact between the host body faces during the shearing process. Eight different types of cable bolt were encapsulated in 40 MPa concrete cylinders, using Stratabinder HS grout. Prior to encapsulation, cable bolts were pretensioned at the desired value using a manual pretensioner. Effects of surface profile, pretension value and debonding on shear strength of cable bolts were investigated. It was found that the shear strength of spiral/indented cable bolts was lower than that of plain cable bolts. Increasing the pretension load decreased the peak shear load of cable bolts. In general, no debonding was observed for spiral/indented cable bolts during shear testing; however, all tested plain cable bolts were debonded.

Effects of surface profiles on the joint formation during magnetic pulse crimping in tube-to-rod configuration

Magnetic pulse crimping is a solid state, high-speed impact crimping technique. In this paper, copper tube was successfully crimped on the steel 1020 rod. Three types of profiles threaded, knurled, and plain profile were created on the steel rod and then a copper tube was crimped on the rod. The influence of surface profiles on the joint strength, surface roughness and microstructure of the joint were analyzed and compared. Compression-shear tests as well as pull-out tests were carried out to compare the strength of the crimped joint. The result of the pull-out tests as well as compression-shear tests revealed that threaded surface profile on the steel rod gives better strength in comparison to the other two profiles. Along the circumference of the Cu-steel composite rod the microstructure images of the joints were taken and analyzed, it was found that there was no gap along the circumference of the sample crimped at 5.3 kJ of discharge energy with plain profile. For surface roughness, the Ra values of the crimped samples at 5.3 kJ were analyzed and it was found that average Ra value of the sample crimped on the threaded base was highest (0.80 μm) among threaded, knurled, and plain base samples.

Effect of Surface Profile on the Material Removal Rate Distribution in CMP Process

Material removal rate (MRR) distribution is a major concern in CMP process. In the published literatures, both experimental and theoretical research, MRR distribution is given without considering the surface profile of wafer. In this paper, the effect of surface profile on the MRR is analyzed based on the Preston equation and the contact pressure distribution calculated by the mixed lubrication model. It is found that the MRR distribution is dramatically affected by the profile of wafer surface, and whatever the polishing pad is conditioned in situ, the MRR distribution will be uniform at last. In addition, the wear of the pad surface induces a decrease of MRR.

縮尺模型によるリブ・ブロック構造壁面の乱反射率測定

Regarding scattering coefficient that represents acoustic scattering of wall surfaces, a reverberation room method for measuring the random-incidence value has recently standardized by ISO 17497-1. The scattering coefficient is widely used in geometric room acoustic simulation, however, there are few measured data available. In this report, a variety of rib and block structure walls are tested by the reverberation room method in order to provide a database of scattering coefficients. Furthermore, characteristics of the scattering coefficients are investigated, especially regarding the effect of surface profile and absorbent finish for rib structures, and that of arrangement for block structures.

The effect of surface profile on the sand erosion of aluminium

Management and prediction of sand erosion on oil and gas equipment are important for the safety, reliability and maintenance of the production facility. Prediction of sand erosion is not a trivial task as it requires an understanding of the fluid flow-field, movement of abrasive particles in this flow-field and their subsequent impact on the target material surface. It is reasonable to assume that once sand erosion occurs on a surface, the rate of erosion would be constant. This is not always the case since the surface topography may change over time. An experiment investigating the sand erosion of a hole centred in a rectangular aluminium plate was designed to explore this phenomenon. The sample was subject to erosion by two 50 kg batches of sand; surface profiles of the hole were measured after each batch. The results suggest that a pre-eroded surface has an increased change of erosion depth compared with a new surface. As erosion progresses, the geometry of the sample alters and, depending on location, the change of erosion depth, relative to the previously eroded profile, on the sample surface varied from -30-50%; slight material build-up occurred on the inner face of the hole due to extrusion processes during erosion.

Construction and Analysis of Nanoscale Simulative Measuring Model for Scanning Near-Field Optical Microscope

This study constructs a novel scanning near-field optical microscope (SNOM) fixed-amplitude simulative measuring model. It uses Al, Si, and O atoms to compose the probe tip and sample to construct the atomic model of SNOM simulative measuring model. It also applies Morse potential to calculate the atomic interaction force between tip and sample on the vibration theory of SNOM. This study compares the edge effect of surface profile between the simulated measurement with experimental measurement; it verifies that the nanoscale simulative measuring model for SNOM is reasonable and accurate. After analyzing the edge effect and error about the surface profile of standard sample by the SNOM simulated measurement, it is found that the factor influencing this surface profile appearance is mainly from the tip shapes. The investigation of the error analysis is referential in compensating the error of SNOM measurement and it can be used to further enhance the accuracy of SNOM measurement.

The effect of surface profile, rock strength and pretension load on bending behaviour of fully grouted bolts

Fully encapsulated rock bolting has, in recent years, become a universally accepted system of ground reinforcement in mining and tunnel construction. The application of bolting systems extends both to rebar as well as cable bolting. The effectiveness of the bolt application has been studied in shear, both by laboratory tests as well as by numerical modeling. A specially constructed double shearing apparatus (DSA) was used to examine the shearing behaviour of a bolt installed perpendicularly across two joints. The experimental study was complemented with three-dimensional numerical analysis. Parameters examined include, the effect of reinforced material on tension/compression zones along the sheared bolt, shear resistance, shear displacement and induced strains and stresses during bolt bending process. The study was undertaken at both free load and pretension conditions. The conclusions drawn from the study were the level of bolt resistance to shear was influenced by bolt profile configuration, the strength of the rock or medium influenced the level of load generated on the bolt and the increased bolt pretension contributed to increased shearing load of the bolted medium. The numerical simulation of the bolt/medium interaction and deformational behaviour were found to be in close agreement with the experimental test results.

The effects of surface profile and interface correlations on X-ray reflectivity from fluid interfaces

Following a brief review of the physics by which X-ray scattering can be made surface sensitive, we will discuss some details of the effects that interfacial roughness and asymmetry of interfacial profiles have on measurements of X-ray specular reflectivity. Experiments related to these effects, including study of the width and interfacial roughness of the liquid/vapour interface for H2O, superfluid 4He, thin wetting films of cyclohexane on Si, and metallic liquid Ga, have been reviewed elsewhere.

Optimum design of tilting pad sliders with one-dimensional continuous surface profiles

The effects of one-dimensional continuous surface profiles on the loadcarrying capacity of both infinitely wide and finite tilting pad slider bearings were investigated and compared with results for a conventional flat surface tilting pad. Pressure distributions are obtained by computer-aided finite difference numerical solutions of Reynolds' equation. These pressure distributions are then used to evaluate the location of the pivot position, loadcarrying capacity, flow rate, side leakage, frictional power loss, coefficient of friction and the temperature rise. Results for infinitely wide and finite tilting pad slider bearings are compared with available analytical solutions to confirm their credibility. The optimized tilting pads with proposed surface profiles have considerably higher load-carrying capacity than the optimized flat-faced tilting pad of the same geometry and lubricant properties. The effect of surface profiles becomes more significant for narrow bearings because the rate of increase in load-carrying capacity compared with conventional flat pads increases with any reduction in the L z L x ratio of the pad. The selection of a particular surface profile also depends mainly on the pad dimensions. Charts are presented for the optimum design of tilting pad slider bearings with newly proposed pad surface profiles by furnishing information on pivot location, load-carrying capacity, flow rate, side leakage, frictional power loss and temperature rise. Numerical examples are provided to demonstrate the applications of these design charts in the analysis or synthesis of a tilting pad slider bearing. An analytical solution of Reynolds' equation for an infinitely wide slider bearing is used to calculate the pivot location, load and flow coefficients for the proposed surface profiles and the results are summarized in Appendix A.

Effect of Surface Profiles on Characteristics of Concentric Recoil Bearings

An object of the design of a concentric recoil bearing is to insure reliable full-film lubrication over as much of the recoil and counter recoil motions as possible. The surface profile has a great effect on the oil film produced in the bearing. A straight bearing profile produces only a thin and unreliable film. A small taper on the leading edge greatly improves the situation. However, a shallow blind slot in the loaded sector of the bearing was the best surface profile of those studied. Although the slot war less than a mil deep, it resulted in a faster acting bearing and an appreciable thicker oil film. At the highest bearing pressure, the 10 millisecond film thickness was almost twice that of the next best profile studied. This design holds great promise, not only for concentric recoil bearings, but also for bearings for reciprocating shafts where the bearings must be fast-acting and where they support large loads. Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubric...

The Influence of Longitudinal and Transverse Profile on the Load Capacity of Pivoted Pad Bearings

An extension of previous work on the effects of surface profile on the load capacity of pivoted pad thrust bearings. Numerical solutions are presented for a square pad having profiles consisting of (a) longitudinal curvature, (b) transverse curvature, and (c) a combination of (a) and (b). Improved load capacity over the flat pad with optimum pivot location is found for some operating conditions including the case of the centrally pivoted pad.