Values Of Roughness Parameters Research Articles

Steady-state existence of passive vector fields under the Kraichnan model

The steady-state existence problem for Kraichnan advected passive vector models is considered for isotropic and anisotropic initial values in arbitrary dimension. The models include the magnetohydrodynamic (MHD) equations, linear pressure model, and linearized Navier-Stokes (LNS) equations. In addition to reproducing the previously known results for the MHD model, we obtain the values of the Kraichnan model roughness parameter xi for which the LNS steady state exists.

Wetting effects on in vitro bioactivity and in vitro biocompatibility of laser micro-textured Ca-P coating

Calcium phosphate (Ca-P) coating on the Ti-6Al-4V alloy enhances osteoblast adhesion and tissue formation at the bone implant interface. In light of this, in the current work a laser-based coating technique was used to synthesize two different micro-textured (100 µm and 200 µm spaced line patterns) Ca-P coatings on the Ti-6Al-4V alloy and its effect on wettability and osteoblast cell adhesion were systematically studied. X-ray diffraction (XRD) analysis of the coated samples indicated the presence of precursor material, Ca10(PO4)6(OH)2 (HA) and various other additional phases such as CaTiO3, Ca3(PO4)2, TiO2 (anatase) and TiO2 (rutile) owing to the reaction between the precursor (HA) and substrate (Ti-6Al-4V) during laser processing. Confocal laser scanning microscopy-based characterization of coated samples indicated that the samples processed at 100 µm line spacing demonstrated a reduced surface roughness and smaller texture parameter value as compared to the samples processed at 200 µm spacing. The surface energy and wettability of the 100 µm spaced samples measured using a static sessile drop technique demonstrated higher surface energy and increased hydrophilicity as compared to the control (untreated Ti-6Al-4V) and the samples processed at 200 µm spacing. The tendency of coated samples for mineralization through generation of an apatite-like phase during immersion in a simulated body fluid was indicative of their in vitro bioactive nature. In light of higher surface energy and increased hydrophilicity the in vitro biocompatibility of the samples with 100 µm line spacing was demonstrated through increased cell proliferation and cell adhesion of mouse MC3T3-E1 osteoblast-like cells.

Effect of filler particles on surface roughness of experimental composite series

ObjectiveThe purpose of this study was to evaluate the effect of different filler sizes and shapes on the surface roughness of experimental resin-composite series.Material and MethodsThirty-three disc-shaped specimens of the series (Spherical-RZD 102, 105, 106, 107, 114 and Irregular-RZD 103, 108, 109, 110, 111, 112) were prepared in a split Teflon mold and irradiated with an halogen light-curing unit (450 mW/cm2 for 40 s) at both top and bottom surfaces. The specimens were stored for 3 months in distilled water. The surface roughness values in form of surface finish-vertical parameter (Ra), maximum roughness depth (Rmax) and horizontal roughness parameter (Sm) were recorded using a contact profilometer. The data were analyzed by one-way ANOVA and the means were compared by Scheffé post-hoc test (α=0.05).ResultsThe lowest surface roughness (Ra) was observed in S-100 (0.079±0.013), while the roughest surface was noted in I-450/ 700/1000 (0.125±0.011) and I-450/1000 (0.124±0.004). The spherical-shape series showed the smoothest surface finish compared to the irregular-shape ones with higher significant difference (p>0.05). The vertical surface roughness parameter (Ra) values increased as the filler size increased yielding a linear relation (r2=0.82). On the contrary, the horizontal parameter (Sm) was not significantly affected by the filler size (r2=0.24) as well as the filler shape.ConclusionsFiller particle’s size and shape have a great effect on the surface roughness parameters of these composite series.

The influence of sanding system on wetting of Paulownia siebold et zucc.

This paper presents the research of influence of wood surface preparation on the wetting ability of polyurethane coatings, by the method of contact angle. The samples were made of two species of Paulownia (Paulownia elongata and Paulownia fortunei). All the samples were processed by planing (molding). After molding, the samples were arranged in groups and sanded. In relation with wood grain direction, each group had a particular system of sanding, based on the numbering of sanding paper, program of displacement of sanding papers with different numbering and the direction of sanding. The quality of wood surface after sanding was expressed by the values of roughness parameters in the system 'M': Ra, Rz, Rv, Rp and Rt. The contact angle was measured using transparent polyurethane (PU) coating and distilled water. The influence of the system of sanding on the values of contact angle was analyzed by roughness parameter Ra.

A Study on Surface Material Measures for Areal Surface Texture Measuring Instruments

In this paper, we propose a design method to create new surface material measures with irregular surface topographies for the calibration of surface texture measuring instruments having various measurement principles. We also propose the verification system for the surface measuring instruments using those surface material measures. Basic design factors of the surface material measures for three-dimensional (3D) surface roughness measurement are also discussed to create the software gauge data with irregular surface topographies. The software gauge data with 3D irregular topographies based on the non-causal 2D auto-regressive model are utilized to design the surface material measures. The proposed procedure can create surface structures of surface material measures with periodical irregular surface topographies and specified roughness parameter values. The proposed method has capability to create surface material measures with variable roughness parameters for arbitrary evaluation area.

CRITICAL ANALYSIS OF MICROWAVE SPECULAR SCATTERING RESPONSE ON ROUGHNESS PARAMETER AND MOISTURE CONTENT FOR BARE PERIODIC ROUGH SURFACES AND ITS RETRIEVAL

The main aim of this paper is to accentuate the sensitivity of correlation length 'l' as an important roughness parameter in quantifying the moisture content of bare soil surfaces with specular scattering. For this purpose, an indigenously designed bistatic scatterometer has been used to generate co-polarized specular data at X-band (10GHz) with incidence angle varied from 30 - {70 - in steps of 10degrees. The moisture and roughness conditions of the bare soil surface were changed under controlled conditions. Twenty seven experimental flelds specifled on the ground of difierent roughness and moisture conditions have been analyzed. Higher level of moisture content with larger correlation lengths was found to be more suitable for observing the efiect of increasing rms height on specular scattering. Kirchhofi approach (KA) considered under the stationary phase approximation (SPA) has been used as an inversion algorithm with the application of genetic algorithm for the retrieval of soil parameters. A good agreement was observed between the experimental and retrieved values of soil moisture content (mv) and roughness parameters (s and l).

Surface Roughness Determination in Turning of Cylindrical Surfaces

The topic of the article is the determination of theoretical values of surface roughness on cylindrical surfaces machined by turning. For the calculation of the values of main roughness parameters (Rmax, Rz, Ra) a general mathematical model was developed, and a computer software based on this model has also developed. In the article this model and the software based on it gets introduced briefly, as the determination of connections between calculated theoretical values and measured data obtained through experiments.

Ge growth on self-affine fractal Si surfaces: influence of surface roughness

We have studied the influence of substrate surface roughness on the growth of Ge on self-affine fractal Si surfaces. Self-affine fractal surfaces can be prepared by irradiating surfaces of solid materials with an energetic ion beam, which modifies the surface morphology predominantly via an erosion process. By tuning the ion beam energy, surface parameters such as surface roughness (σ0) and correlation length (ξ), can be controlled. Values of σ0 and σ0/ξ affect the effective free energy of the surface. When materials are grown on surfaces with different values of surface roughness parameters, the morphology of the deposited layer is expected to be influenced. In comparison with an earlier study where 2 MeV Si ion irradiation was used, we have produced surfaces with larger values of σ0 and σ0/ξ by irradiating the surfaces with 45 keV Si ions. We have made a comparison for Ge growth on Si surfaces irradiated with 2 MeV and 45 keV Si ions and have observed remarkably different growth behaviour. Upon Ge deposition, in the former case, the surface roughness decreases at smaller length scales and remains practically unchanged at larger length scales. This indicates that Ge has grown preferentially within the valleys of the rough surface. In the latter case, where σ0 is large and ξ is small on the substrate surface, the roughness increases at all length scales by almost a factor of 2, upon Ge deposition, indicating the lack of preferential growth within the surface valleys. Following Ge deposition, in the former case the roughness exponent increases from 0.82 to 0.99, while in the latter case it remains practically unchanged (∼0.83). Roughness parameters of the substrate surface are found to have a significant influence on the morphology of the overlayers.

Evaluation of the SMOS L-MEB passive microwave soil moisture retrieval algorithm

Soil moisture will be mapped globally by the European Soil Moisture and Ocean Salinity (SMOS) mission to be launched in 2009. The expected soil moisture accuracy will be 4.0 %v/v. The core component of the SMOS soil moisture retrieval algorithm is the L-band Microwave Emission of the Biosphere (L-MEB) model which simulates the microwave emission at L-band from the soil–vegetation layer. The model parameters have been calibrated with data acquired by tower mounted radiometer studies in Europe and the United States, with a typical footprint size of approximately 10 m. In this study, aircraft L-band data acquired during the National Airborne Field Experiment (NAFE) intensive campaign held in South-eastern Australia in 2005 are used to perform the first evaluation of the L-MEB model and its proposed parameterization when applied to coarser footprints (62.5 m). The model could be evaluated across large areas including a wide range of land surface conditions, typical of the Australian environment. Soil moisture was retrieved from the aircraft brightness temperatures using L-MEB and ground measured ancillary data (soil temperature, soil texture, vegetation water content and surface roughness) and subsequently evaluated against ground measurements of soil moisture. The retrieval accuracy when using the L-MEB ‘default’ set of model parameters was found to be better than 4.0 %v/v only over grassland covered sites. Over crops the model was found to underestimate soil moisture by up to 32 %v/v. After site specific calibration of the vegetation and roughness parameters, the retrieval accuracy was found to be equal or better than 4.8 %v/v for crops and grasslands at 62.5-m resolution. It is suggested that the proposed value of roughness parameter H R for crops is too low, and that variability of H R with soil moisture must be taken into consideration to obtain accurate retrievals at these scales. The analysis presented here is a crucial step towards validating the application of L-MEB for soil moisture retrieval from satellite observations in an operational context.

On correlation between fractal dimension and profilometric parameters in characterization of surface topographies

This study reports and discusses the results of investigation of correlation between fractal dimensions D EIS inferred from electrochemical impedance spectroscopy measurements and profilometric parameters obtained by contact (stylus) and non-contact (laser) profilometric methods. The research, conducted on two types of printing plates with different aluminium oxide surface topographies, revealed that there exists a good correlation between D EIS and certain profilometric parameters, although there are significant differences in values of roughness parameters inferred from stylus method in respect to these inferred from the non-contact measurements. The best correlation, regardless of the applied method or printing plate type, exists between D EIS and the average surface roughness parameter R a . Generally, better correlation between fractal dimension and profilometric parameters is observed for parameters inferred from contact measurements than for those obtained by non-contact (laser) methods. The correlations between fractal dimension D EIS, which is a very good descriptor of overall surface topography, and various profilometric parameters, provide significant information on the surface topography and an additional insight into processes responsible for its changes.

SIPAR_ID: Freeware for surface irrigation parameter identification

SIPAR_ID is a software based on a robust multiobjective inverse modeling technique for estimating field values of infiltration and roughness parameters of a surface irrigation event under both steady and variable inflow conditions. Its simulation engine is quite flexible and accurate thanks to a hybrid model that combines a volume-balance model with artificial neural networks. SIPAR_ID also provides an estimate of the uncertainty and sensitivity of the identified parameters.

Performance evaluation of solar air heater having expanded metal mesh as artificial roughness on absorber plate

A parametric study of artificial roughness geometry of expanded metal mesh type in the absorber plate of solar air heater duct has been carried out and compared with smooth duct. The performance evaluation in terms of energy augmentation ratio ( EAR), effective energy augmentation ratio ( EEAR) and exergy augmentation ratio ( EXAR) has been carried out for various values of Reynolds number ( Re) and roughness parameters of expanded metal mesh roughness geometry in the absorber plate of solar air heater duct. It is found that the augmentation ratios decrease at faster rate with Re in the order of EAR, EEAR and EXAR. It is also found that augmentation ratios increase with increase in duct depth and intensity of solar radiation. The artificially roughened solar air heater duct performs better as per EAR or heat energy gain criteria for any values of Re and roughness parameters of expanded metal mesh. The EAR is high for the parameters of expanded metal mesh type roughness geometry which create more turbulence, however the pump work required for flow of air will also increase. The EXAR is a more suitable criterion to incorporate the quality of heat collected and pump work required. The EXAR is more for higher duct depth and low Re range. Based on EXAR the suitable design parameters of expanded metal mesh roughness geometry are determined.

Monte Carlo simulation study of scanning electron microscopy images of rough surfaces

In this paper, we have developed a Monte Carlo (MC) simulation method for calculation of scanning electron microscopy (SEM) images of rough surfaces. The roughness structure is constructed in a finite element triangulated mesh by using a Gaussian function to describe the distribution of amplitude of the random rough peaks. Further spatial subdividing can accelerate the calculation and improves MC simulation efficiency. The MC model is based on the using of the Mott cross section for description of the electron elastic scattering and the using of the full Penn algorithm in a dielectric functional approach to the electron inelastic scattering. This simulation relates directly a defined rough surface structure modeling described by exact values of roughness parameters to the contrast observed in a SEM image, enabling the investigation of the influence of line edge roughness to the critical dimension (CD) metrology of a metal-oxide-semiconductor device by SEM. Example calculation of line images with sidewall roughness demonstrates that the present MC simulation method is useful for CD metrology of nanostructures by CD-SEM and, especially, for the linewidth measurement in the integrated circuit industry.

Heat transfer and friction factor correlations for a duct having dimple-shape artificial roughness for solar air heaters

The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the underside of the absorber plate of a solar air heater duct. Under the present work, an experimental study has been carried out to investigate the effect of roughness and operating parameters on heat transfer and friction factor in a roughened duct provided with dimple-shape roughness geometry. The investigation has covered the range of Reynolds number ( Re ) from 2000 to 12,000, relative roughness height ( e / D ) from 0.018 to 0.037 and relative pitch ( p / e ) from 8 to 12. Based on the experimental data, values of Nusselt number ( Nu ) and friction factor ( f r ) have been determined for different values of roughness and operating parameters. In order to determine the enhancement in heat transfer and increment in friction factor values of Nusselt number and friction factor have been compared with those of smooth duct under similar flow conditions. Correlations for Nusselt number and friction factor have been developed for solar air heater duct provided such artificial roughness geometry.

Comparison of fractal and profilometric methods for surface topography characterization

In this study microstructural and roughness characterization of surface of aluminium foils used in lithographic printing process was performed by contact and non-contact profilometric methods and fractal analysis. Significant differences in roughness parameters values inferred from stylus method in respect to those inferred from the non-contact measurements were observed. The investigation of correlation between various fractal dimensions obtained from gray-scale SEM micrographs and binary images resulting from median filtering of the original SEM micrographs as well as selected relevant roughness parameters shows that there is a strong correlation between certain roughness parameters and particular fractal dimensions. This correlations permit better physical understanding of fractal characteristics and interpretation of the dynamics of surface roughness change through processing. Generally these correlations are more suitable for parameters obtained by stylus method than those inferred from the laser-based measurements.

Global and systematic demonstration for the practical usage of a direct in vivo measurement system to evaluate wrinkles

The global and systematic demonstration for the practical usage of a direct three-dimensional in vivo measurement system (PRIMOS) to evaluate wrinkles was investigated. Ten repetitive measurements of the corner of the eye of a subject showed that the coefficient of variation (CV)% value was 7.0% in a typical line-length roughness parameter R(a) (the arithmetic mean of roughness), and that the CV% value in a typical surface area roughness parameter S(a) was 2.4%. The relationships between the roughness values obtained from the corners of the eye and the age or wrinkle scores of Japanese women aged 10-70 years was examined. The values of several roughness parameters within the evaluation line length or surface area increased with age and showed a good correlation coefficient (r > 0.743). Similar relationships between the wrinkle scores and the values of roughness parameters were observed (r > 0.699). The roughness values were widely distributed even in the same wrinkle score because the measurement areas were limited and the values of skin roughness, including the microreliefs and/or small warts, were included in the calculation. However, changes in roughness values are considerable following treatment with potent active ingredients such as retinoic acid, so that this in vivo evaluation method is sufficient to objectively evaluate wrinkles. We conclude that the direct three-dimensional analysis of wrinkles in vivo should become a popular method to objectively evaluate wrinkles in clinical tests of wrinkle-smoothing ingredients or following cosmetic surgery to provide evidence of quantitative results.

Thermal cycling experiments for glass moulds surface texture lifetime prediction – Evaluation with the help of statistical techniques

In this study, test specimens consisting of stainless steel that is widely used in manufacturing glass household goods, another stainless steel specimen and the specimen of the latter material that was surface boronized are subjected to glass forming temperature in laboratory conditions, and the changing surface roughness parameters have been monitored with precise measurement techniques. The information obtained from surface texture was not only useful for determining mould surface performance but could also be used as a distinguishing mark about the quality of glassware. The results are informative about the effects of surface texture alterations during thermal cycling operations to the mould’s lifetime. The data that were obtained have been evaluated by using SPSS 13.0 (Statistical Package for Social Science) and a first-order mathematical model that gives R a (arithmetical average roughness) parameter value against cycling number, and last but not the least some material specifications have been established.

A multiscale topography analysis of ground stainless steel and titanium alloys

This study aims to perform a multiscale analysis of abraded surfaces of 316L austenitic stainless steel and titanium alloys (TiAl6V4) grinded at different paper grades. The authors propose to answer the following question: For a given distribution of silicon carbide grains of the paper, what is the best roughness parameter and at which scale must it be evaluated better to discriminate the effect of the mechanical properties of the materials? Paper grades from 80 to 4000 were used under identical pressure and erosion time. It can be concluded that the values of the amplitude roughness parameters depend on the observation scale. It is outlined that the abrasion process is very reproducible. A statistical analysis is then proposed, first, to define a classification of the relevance of the roughness parameters for each grain size distribution, and second, to determine at which scale the mechanical properties of the bulk are more influenced for all paper grades. Finally, at relevant scales, the Abbott amplitude parameters roughness kernel (RK) is the best parameter to discriminate the paper grade effect. The mean distance between asperities (SM) is the preferred method for determining the wear effect on materials and the linear mean normalizing autocorrelation (AMNLN) is the preferred method for determining the interaction between paper grade and materials.

Deriving distributed roughness values from satellite radar data for flood inundation modelling

Because of a lack of spatially distributed evaluation data flood inundation modelling is commonly performed with simplified flood propagation models that very often consider only one channel roughness parameter value to be calibrated. This concept as such is debatable, as friction values are known to be spatially heterogeneous. Moreover, with (over-) simplified model structures, it is clear that distributed simulations may consistently perform well at a given location whilst underperforming at another. Using only limited field data in model calibration, it is not possible to gather enough information on local model errors to improve the modelling concept. However, new processing procedures of remotely sensed flood imagery allow model calibration to be performed at any desired location. Such spatially distributed data can provide enough information to assess models locally. This local evaluation enables the modeller to define and set spatially distributed patterns of model parameters. Using the 2003 River Alzette (G.D. of Luxembourg) flood event recorded by the ENVISAT satellite, this study demonstrates that by directing the flood-modelling concept towards spatially clustered roughness parameters conditioned on remote sensing, it is possible to identify a model structure that generates acceptable model simulations not only at the reach scale but also locally. Applying the same procedure on earlier events with larger magnitude generates similar parameter clusters that are correlated with those obtained with the 2003 ENVISAT flood event. This illustrates the great potential that remote sensing holds in terms of identifying new ways to test existing model concepts and to contribute to the development of improved flood inundation models. The findings thus support the long-debated hypothesis that remote sensing improves our understanding and thus modelling of complex environmental processes, such as floods.

Eddy correlation flux measurements: The sediment surface area that contributes to the flux

We investigated the size and shape of the area on the sediment surface, the so‐called footprint, that contributes to the flux in subaqueous eddy correlation measurements. Tracer tracking simulations were performed for a dissolved conservative tracer released from the sediment surface into a current‐driven flow not affected by density stratifications and surface waves. Simulations revealed that the footprint length (l) can be calculated as l = −2.783 − 158.7h + 159.2h2 − 120.8h log(z0) (all units in m) for eddy correlation measurements heights (h) between 0.05 and 0.3 m above the sediment surface and for sediment surface roughness parameter (z0) values between 7.04 × 10−6 and 0.01 m. The upstream distance (xmax) to the location that contributes the strongest flux signal can likewise be estimated as xmax = −0.09888 − 11.53h + 10.25h2 ‐ 6.650h log (z0). Because vertical turbulent mixing scales with mean current velocity, l and xmax are independent of current velocity. The footprint width (w) can be calculated as w = 6.531h. These expressions were developed for water depths (H) of H > 27h. In the depth interval 6.7h > H > 27h, l can be calculated by multiplying the length, as given above, by the factor 1 + 8.347exp(−0.2453 H/h), whereas xmax is independent of H. For H > 6.7h, the tracer transfer rate over the air‐water interface controls the size and shape of the footprint. All expressions are valid for isotropic turbulence, but as a first‐order estimate, the expressions for l and xmax also hold for anisotropic conditions. In contrast, w scales with √(Ey/Ez), where Ey and Ez are the transverse and the vertical eddy diffusivity, respectively. Finally, we describe how site‐specific values of z0 and levels of anisotropy in a turbulent near‐bottom flow can be extracted directly from eddy correlation measurements.