Surface Roughness Index Research Articles

Surface roughness and refractive index changes in contact lens induced by lens care systems.

The aim of this study was to analyze the influence of different lens care systems in surface roughness and refractive index (RI) of contact lenses (CL). This information provides us with a better understanding of how care solutions affect CL materials. Several CL and three commercially available and appropriate lens care solutions were used (two polyhexamethylene biguanide and one hydrogen peroxide care systems). Lenses were immersed in the lens care systems, and then measurements with CLR 12-70 digital automated refractometer and atomic force microscopy analysis on Tapping mode were recorded. The measurements were performed before and after the lenses were immersed in each care solution. Significant changes were observed on the CL materials when exposed to lens care systems. All the materials changed, to a greater or lesser extent, their roughness and RI, after being immersed in the different solutions. The water content varied between 0% (Nelfilcon A in ReNu Multiplus, Senofilcon A in AOSEPT Plus, and Methafilcon A in Solocare Aqua) and 4.1% (Hilafilcon B in Solocare Aqua) The higher change in roughness was obtained with ReNu Multiplus in the lens Comfilcon A (with an increase of 27.2 nm) and Senofilcon A (with an increase of 16.7 nm). This study suggests that lens care systems play an important role in surface roughness and RI of CL.

A green chemical approach for biotransformation of Cr(VI) to Cr(III), utilizing Fusarium sp. MMT1 and consequent structural alteration of cell morphology

Chromium (Cr) resistant fungal strain capable of reducing toxic hexavalent chromium to non-toxic trivalent form was isolated from tannery effluent. The strain belonged to the genus Fusarium as concluded on the basis of sugar utilization and molecular profiling studies. The Translation Elongation Factor 1-α (TEF) gene sequence of the strain was identified with the accession number JX170375 in NCBI. The biotransformation of Cr(VI) to Cr(III) was optimized by the following physico-chemical parameters: incubation temperature: 25°C, incubation time: 72h and initial pH: 5.0. Chromium reduction efficiency of the strain was observed to be 100% in growth medium after 72h of incubation. Proteomic profiling indicated a number of proteins to be down regulated in the fungal cell on exposure to chromium. Atomic force, confocal laser scanning and scanning electron micrographs revealed enhanced surface roughness index (5.2±0.2nm to 11.53±0.3nm), significant swelling and formation of cage like structures on the cell surface induced by the presence of Cr in growth medium. Thus biotransformation of Cr(VI) in industrial waste achieved with the isolated Fusarium sp. MMT1 strain, utilizes a green technique which is immensely beneficial for bioremediation.

Measuring Surface Roughness through the Use of Digital Photography and Image Processing

This paper aims to provide a quantitative method that employs image processing in the assessment of surface roughness based on digital photograph field surveys, as in previous studies employing the outdoor integrated digital photography and image processing (O-IDIP) method. Digital photographs were taken on two different days under contrasting outdoor lighting conditions (overcast versus clear sky). Images were captured mounted on a tripod close up to the surface of a 380-year-old wall located at the University of Oxford Botanic Garden in the City of Oxford, UK. Sampling points were established at regular intervals along the border wall and encompassed sections facing west, north, and east, respectively along the survey. Two photographs were taken with a digital camera at each sampling point, one containing a color chart used to calibrate outdoor lighting conditions across images, which was excluded from the other photographic pair. Histogram-based quantification was performed based on images converted to Lab Color mode. The 10-step calibration procedure presented in this paper required more adjustments of contrast. However, more adjustments were not required under a clear sky. Std Dev L measurements were used to establish categories in a simple 3-point roughness index, namely the surface roughness index (SRI). The results denote that pitting did not affect surface roughness measurements. The study shows that it is possible to use Std Dev L measurements to quantify surface roughness on a comparative basis.

Torque reduction and workpiece finishing effects due to voltage sags in turning processes

The use of computer numerical control machine tools allows the industries to reduce costs and operating time while increasing the quality of the manufactured products. However, any malfunction in the equipment can partially affect the manufacturing process or even provoke the complete production interruption. For this reason, studies about phenomena that could affect the machinery are of interest for the manufacturing industry. In this sense, any disturbance in the electric system could either damage or affect the correct machine operation. The contribution of this work is to estimate the repercussion of voltage sags in conventional turning processes. This study is centered in the parameters of spindle motor torque and workpiece rugosity. A methodology and an analysis procedure are proposed to achieve the mentioned task. The methodology consists of estimating the values of power and torque during the electrical disturbance and establishing their relationship with the surface roughness index, Ra. The input parameters are the voltage, current and spindle speed that are monitored in a computer numerical control lathe affected by different levels of sags; also, the measurement of the workpiece surface roughness is used in the methodology. The analysis consists of calculating torque and rugosity variations due to induced voltage sags in order to find the effects of the sags in the machine performance. Results show that there exists a relationship between the voltage sags, the variations in torque and the rugosity.

Research on Integrated Fire Danger Index Application Based on Ignition and Fire

The use of MODIS remote sensing data desired physical concept fuel preheating energy based on data, by fully considering the heat in the ignition probability index actual transfer heat loss in the process of combining fire probability index by population density and surface roughness index. Construction of integrated fire danger index by ignite two exponential probability index and fire probability index. After the analysis of forest fire in Heilongjiang in October 12, 2004 fire points results, show that the model can obtain better forecasting results. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

A‐SiC:H Films by Remote Hydrogen Microwave Plasma CVD From Ethylsilane Precursors**

Amorphous, hydrogenated, silicon carbide (a‐SiC:H) films are deposited in the remote hydrogen microwave plasma (RP‐CVD) process using diethylsilane as a single‐source precursor. The effect of substrate temperature (TS) on the kinetics of RP‐CVD, chemical composition, structure, surface morphology, and properties (density, refractive index, and extinction coefficient) of the resulting a‐SiC:H films is investigated. The TS dependence of film growth rate implies that RP‐CVD is an adsorption‐controlled process. The increase of TS from 30 °C to 350 °C causes the elimination of organic moieties from the film and the formation of a SiC network structure. The relationships between the content of SiC bonds, represented by the relative integrated intensity of the SiC IR band, and the film properties are determined. The number of SiC bonds is found to be a key parameter in the control of the examined film properties. The films deposited at TS = 350 °C appear to be very dense materials exhibiting small surface roughness and high refractive index. The results of the present study are compared with those reported for a‐SiC:H films produced by RP‐CVD from a triethylsilane precursor.

A rapid and repeatable method to deposit bioaerosols on material surfaces

A simple method for repeatably inoculating surfaces with a precise quantity of aerosolized spores was developed. Laboratory studies were conducted to evaluate the variability of the method within and between experiments, the spatial distribution of spore deposition, the applicability of the method to complex surface types, and the relationship between material surface roughness and spore recoveries. Surface concentrations, as estimated by recoveries from wetted-wipe sampling, were between 5×103 and 1.5×104CFUcm−2 across the entire area (930cm2) inoculated. Between-test variability (Cv) in spore recoveries was 40%, 81%, 66%, and 20% for stainless steel, concrete, wood, and drywall, respectively. Within-test variability was lower, and did not exceed 33%, 47%, 52%, and 20% for these materials. The data demonstrate that this method is repeatable, is effective at depositing spores across a target surface area, and can be used to dose complex materials such as concrete, wood, and drywall. In addition, the data demonstrate that surface sampling recoveries vary by material type, and this variability can partially be explained by the material surface roughness index. This deposition method was developed for use in biological agent detection, sampling, and decontamination studies, however, is potentially beneficial to any scientific discipline that investigates surfaces containing aerosol-borne particles.

Influence of Track Support Stiffness of Ballasted Track on Dynamic Wheel-Rail Forces

Dynamic wheel-rail force can be limited to high-frequency components owing to imperfections in the wheel-rail contact surface (P1) and may also contain low-frequency components owing to coupled wheel-rail vibrations in phase on the ballast (P2). Previous studies on dynamic wheel-rail forces have focused on the quality index of surface roughness (QI) of only rail welds. In this study, the influences of rail surface roughness and track stiffness of a ballasted track on dynamic wheel-rail forces currently employed in high-speed lines were assessed by performing field measurements using actual vehicles running along the service lines. The theoretical dynamic wheel-rail force determined using a previous theory was compared with the dynamic wheel-rail force determined through field measurements. At a constant QI, an increase in the vertical track stiffness caused an increase in P2. Therefore, the vertical track stiffness affects P2 more strongly than P1. Hence, P1 is more affected by QI and train velocity than is P2. Further, it is inferred that the results of multiple regression analysis obtained using measured data such as QI, vertical track stiffness, and P2 can be used to predict the peak dynamic forces acting on ballasted tracks.

Growth of silver on ZnO and SnO2 thin films intended for low emissivity applications

In the present work we have investigated the relationships existing between the optical properties and the growth mechanism, microstructure and surface roughness of SnO2 and ZnO oxide films prepared by magnetron sputtering under conditions resembling those utilized in industry. Thin films of these oxides with different thicknesses were characterized by atomic force microscopy, glancing incidence X-ray diffraction (GIXRD), X-ray reflectometry and spectroscopic ellipsometry. The roughness evolution of the film properties (density, surface roughness and refraction index) as a function of their thickness has been evaluated within the concepts of the Dynamic Scaling Theory of thin film growth. Zinc oxide films were rougher than tin oxide films of similar thickness, indicating a different growing mechanism for the two materials. Silver was evaporated onto the surface of the two oxide thin films and its earlier stages of nucleation studied by background analysis of the X-ray photoemission spectra. A different nucleation mechanism was found depending on the nature of the oxide acting as substrate. The superior performance of the zinc oxide based low emissive coatings is related with a better wetting of silver on the surface of this oxide despite the comparatively lower roughness of the tin oxide layers.

Label-Free Shape-Based Selection of Cardiomyocytes with on-Chip Imaging Cell Sorting System

We have examined the method for the label-free optical microscopic image-based selection of cardiomyocytes from the mixture of collagenase-digested embryonic mouse heart cells using the on-chip imaging cell sorter system, in which 1/2000 s real-time high-speed camera-based phase-contrast cell image recognition was performed. To separate the cardiomyocytes from other cells including fibroblasts, we distinguished the roughness of the cell surface quantitatively as the index of sorting. The selected cells with smooth surface (roughness index not more than 1.1) for cardiomyocytes, and confirmed that the more than 80% of the collected and recultivated cells were self-beating and the 99.2% of them were identified as cardiomyocytes by immunostaining. The results indicates the potential of the label-free cell purification using imaging cell sorting system, especially for cardiomyocytes by the index of their cell surface roughness, which might be applicable for purification of cardiomyocytes for regenerative medicine.

Quantification of Soil Surface Roughness Evolution under Simulated Rainfall

<abstract><title><italic>Abstract.</italic></title> Soil surface roughness is commonly identified as one of the dominant factors governing runoff and interrill erosion. The objective of this study was to compare several existing soil surface roughness indices and to test the use of the revised triangular prism surface area method (RTPM) to calculate the fractal dimension as a roughness index. A silty clay loam soil was sampled, sieved to four aggregate sizes, and each size was packed in soil trays in order to derive four different soil surface roughness classes. Rainfall simulations using an oscillating nozzle simulator were conducted for 90Â min at 50.2 mm h^-1 average intensity. The surface microtopography was digitized by an instantaneous profile laser scanner before and after the rainfall application. Calculated roughness indices included random roughness, variogram sill and range, fractal dimension and fractal length using a fractional Brownian motion (fBm) model, variance and correlation length according to a Markov-Gaussian (MG) model, and fractal dimension using the RTPM. Random roughness is shown to be the best estimator to significantly distinguish soil surface roughness classes. When taking spatial dependency into account, the variogram sill was the best alternative. The fractal dimension calculated from the fBm model did not yield good results, as only short-range variations were incorporated. The MG variance described the large-scale roughness better than the parameters of the fBm model did. The fractal dimension from the RTPM performed well, although it could not significantly discriminate between all roughness classes. Since it covered a greater range of scales, we believe that it is a good estimator of the overall roughness.

A semi-empirical inversion model for assessing surface soil moisture using AMSR-E brightness temperatures

Summary In 2004–2005, 2007 and 2009, three major drought disasters occurred in Guangdong Province of southern China, which caused serious economic losses. Hence, it has recently become an important research subject in China to monitor surface soil moisture (SSM) and the drought disaster quickly and accurately. SSM is an effective indicator for characterizing the degree of drought. First, using the brightness temperatures (Tb) of the Advanced Microwave Scanning Radiometer on the EOS Aqua Satellite (AMSR-E), a modified surface roughness index was developed to map the land surface roughness. Then by combining microwave polarization difference indices (MPDI)-based vegetation cover classification and the modified surface roughness index, a simple semi-empirical model of SSM was derived from the passive microwave radiative transfer equation using AMSR-E C-band Tb and observed surface soil temperature (Ts). The model was inverted to calculate SSM. The results showed the ability to discriminate over a broad range of SSM (7–73%) with an accuracy of 2.11% in bare ground and flat areas (R2 = 0.87), 2.89% in sparse vegetation and flat surface areas (R2 = 0.85), about 6–9% in dense vegetation areas and rough surface areas (0.80 ⩽ R2 ⩽ 0.83). The simulation results were also validated using in situ SSM data (R2 = 0.87, RMSE = 6.36%). Time series mapping of SSM from AMSR-E imageries further demonstrated that the presented method was effective to detect the initiation, duration and recovery of the drought events.

Improvement of die life with surface texture control and solid lubricant

Abstract The methodology of controlling the surface texture of dies by means of Hybrid-shot peening was examined for the improvement of the die life cycle applied to high strength steel sheets. Hybrid-shot is double-shot peening, where the first treatment is performed using large particles, and the second one is performed with finer shot particles. The specimens of tool steels for dies treated by Hybrid-shot showed a high resistance against galling which was evaluated by the galling generation load of the draw bead test by using an oil lubricant, compared with the single shot specimens. This result suggested that the surface texture influenced the galling property. For a quantitative analysis of surface texture of die material, Fast Fourier Transformation (FFT) was used. Findings revealed that the ratio of the spectrum amplitude between high and low frequencies calculated by FFT corresponded to the galling generation load of draw bead tests. On the other hand, the conventional index of surface roughness, Rz, had no relationship to the galling generation load. Furthermore, the effect of solid lubricant, that is, the powder produced by scallop shell, on the galling property was studied. The addition of fine scallop shell powder in the oil lubricant increased the galling generation load.

Rugosidade da superfície de um Cambissolo Húmico relacionada com o preparo e compactação do solo sob chuva natural

A rugosidade superficial do solo é uma característica importante, pois influencia a infiltração e a armazenagem de água no solo, a retenção de sedimentos na superfície e a erosão hídrica. Por sua vez, a rugosidade é influenciada pelo preparo, umidade e compactação do solo, pelos resíduos culturais, pelo efeito residual do uso do solo e pela erosividade da chuva. Este trabalho teve o objetivo de quantificar o efeito do tipo de preparo, da compactação do solo e da erosividade da chuva sobre o índice de rugosidade superficial ao acaso modificado (RRM), em um experimento conduzido sob chuva natural em um Cambissolo Húmico Alumínico léptico, com declividade média de 0,03 m m-1, entre setembro e novembro de 2008, em Lages, SC, com os seguintes tratamentos: (1) superfície quase lisa em solo compactado (LIC); (2) superfície quase lisa em solo não compactado (LINC); (3) uma aração e duas gradagens em solo compactado (PCC); (4) uma aração e duas gradagens em solo não compactado (PCNC); (5) uma escarificação em solo compactado (ESC); e (6) uma escarificação em solo não compactado (ESNC). O microrrelevo do solo foi medido com rugosímetro mecânico de varetas, em seis oportunidades: imediatamente antes e imediatamente após instalar os tratamentos; e após a ocorrência de cada um dos valores de erosividade (EI30) da chuva: 136, 190, 630 e 265 MJ mm ha-1 h-1. O preparo do solo com aração e gradagens e com escarificação aumentou o índice RRM em relação a antes do preparo, tanto em solo não compactado quanto em solo compactado. O aumento desse índice foi de 3,72 vezes em aração e gradagens e de 3,88 vezes na escarificação, na média do solo compactado e não compactado. A compactação do solo aumentou o índice RRM, independentemente do tipo de preparo. No caso da aração e gradagens, o aumento nesse índice foi de 4,58 vezes no solo compactado e de 3,04 vezes no não compactado, logo após o preparo; em se tratando da escarificação, em solo compactado o aumento pelo preparo foi de 5,49 vezes e de 2,61 vezes no solo não compactado, também logo após o preparo. A erosividade da chuva diminuiu o índice RRM, independentemente do tipo de preparo e da compactação do solo, cuja relação foi descrita pelo modelo y = ae-bx.

Ultrasonic reflection coefficient and surface roughness index of OA articular cartilage: relation to pathological assessment

BackgroundEarly diagnosis of Osteoarthritis (OA) is essential for preventing further cartilage destruction and decreasing severe complications. The aims of this study are to explore the relationship between OA pathological grades and quantitative acoustic parameters and to provide more objective criteria for ultrasonic microscopic evaluation of the OA cartilage.MethodsArticular cartilage samples were prepared from rabbit knees and scanned using ultrasound biomicroscopy (UBM). Three quantitative parameters, including the roughness index of the cartilage surface (URI), the reflection coefficients from the cartilage surface (R) and from the cartilage-bone interface (Rbone) were extracted. The osteoarthritis grades of these cartilage samples were qualitatively assessed by histology according to the grading standards of International Osteoarthritis Institute (OARSI). The relationship between these quantitative parameters and the osteoarthritis grades was explored.ResultsThe results showed that URI increased with the OA grade. URI of the normal cartilage samples was significantly lower than the one of the OA cartilage samples. There was no significant difference in URI between the grade 1 cartilage samples and the grade 2 cartilage samples. The reflection coefficient of the cartilage surface reduced significantly with the development of OA (p < 0.05), while the reflection coefficient of the cartilage-bone interface increased with the increase of grade.ConclusionHigh frequency ultrasound measurements can reflect the changes in the surface roughness index and the ultrasound reflection coefficients of the cartilage samples with different OA grades. This study may provide useful information for the quantitative ultrasonic diagnosis of early OA.

Effect of soil surface roughness and scene components on soil surface bidirectional reflectance factor

Wang, Z., Coburn, C. A., Ren, X. and Teillet, P. M. 2012. Effect of soil surface roughness and scene components on soil surface BRF. Can. J. Soil Sci. 92: 297–313. Bidirectional Reflectance factor (BRF) data of both rough [surface roughness index (SRI) of 51%] and smooth soil surfaces (SRI of 5%) were acquired in the laboratory under 30° illumination zenith angle using a Specim V10E imaging spectrometer and an Ocean Optics non-imaging spectrometer mounted on the University of Lethbridge Goniometer System version 2.5 (ULGS-2.5) and version 2.0 (ULGS-2.0), respectively. Under controlled laboratory conditions, the rough soil surface exhibited higher spectral reflectance than the smooth surface for most viewing angles. The BRF of the rough surface varied more than the smooth surface as a function of the viewing zenith angle. The shadowing effect was stronger for the rough surface than for the smooth surface and was stronger in the forward-scattering direction than in the backscattering direction. The pattern of the BRF generated with the non-image based data was similar to that generated with the whole region of interest (ROI) of the image-based data, and that of the whole ROI of the image-based data was similar to that of the illuminated scene component. The BRF of the smooth soil surface was dominated by illuminated scene component, i.e., the sunlit pixels, whereas the shaded scene component, i.e., the shaded pixels, was a larger proportion of the BRF of the rough soil surface. The image-based approach allowed the characterization of the contribution of spatial components in the field of view to soil BRF and improved our understanding of soil reflectance.

Mechanical and ellipsometry measurements of thin TiN layer prepared by PIII

Titanium nitrides have good mechanical, biomedical and optical properties, therefore they are used to harden and protect cutting and sliding surfaces and as a non-toxic exterior for bio-medical applications. Nitrogen plasma immersion implantation (PIII), in which the diffusion of nitrogen from low pressure r.f. plasma is combined with the implantation of nitrogen ions at energies up to 30 kV, is an effective tool for nitriding titanium and titanium alloys. In this work, samples of pure titanium were nitrided by PIII at different negative high voltage pulses. The properties and the characteristics of the processed samples were evaluated using X-ray diffraction (XRD), Auger electron spectroscopy (AES), ball-on-disk type tribometer, surface profilemeter, and ellipsometry measurements. The results show that, the wear resistance of the untreated sample in comparison to the PIII treated samples is extremely poor and the friction coefficient for the PIII treated samples is decreased to the half value in comparison to the untreated titanium, this attributed to the formation of the solid solution titanium α-Ti(N) and the cubic TiN phases. Ellipsometric measurements were carried out on the PIII treated samples at different negative high voltage pulses. A three layers model was used to fit the calculated data to the experimental ellipsometric spectra. The thickness, surface roughness and refractive index increase with increasing the negative high voltage pulses. The refractive index at 550 nm increases from 1.83 to 2.09 as the negative high voltage pulses increases from 10 to 30 kV.

Method for Determination of the Expected Roughness of Cut Surfaces

Nowadays the manufacturing companies create stricter and stricter demands on quality requirements of surfaces machined by cutting. The fulfilment of these requirements is often not an easy task, and in addition technologists should deal with the economic aspects too. Surface roughness indexes are important parameters in characterization of the quality of parts, especially in case of engaging and sliding one another machine elements influences remarkably their tribological properties and lifespan. Therefore it is indispensably important to completely satisfy the surface roughness requirements. It can mean a great help, if the prospective value of roughness indexes can be predicted in advance for the actual machining environment, since the selection of the optimal tool-geometrical and technological parameters become possible. Such a method will be introduced in the paper, by the help of which theoretical values of surface roughness can be determined for single point cutting by the help of an analytical model. A general mathematical model is introduced, by the help of which edge geometry of every realistically evolving tool can be described. Theoretical values of the relevant roughness indexes used in practice can be calculated by the application of this model. The connection with the real roughness data gained by experiments can be written down after this, hereby the surface roughness can be predicted, and thus the planning of technology can be faster and more efficient.

Neurocognitive derivation of protein surface property from protein aggregate parameters.

Current work targeted to predicate parametric relationship between aggregate and individual property of a protein. In this approach, we considered individual property of a protein as its Surface Roughness Index (SRI) which was shown to have potential to classify SCOP protein families. The bulk property was however considered as Intensity Level based Multi-fractal Dimension (ILMFD) of ordinary microscopic images of heat denatured protein aggregates which was known to have potential to serve as protein marker. The protocol used multiple ILMFD inputs obtained for a protein to produce a set of mapped outputs as possible SRI candidates. The outputs were further clustered and largest cluster centre after normalization was found to be a close approximation of expected SRI that was calculated from known PDB structure. The outcome showed that faster derivation of individual protein's surface property might be possible using its bulk form, heat denatured aggregates.

Comparative study of physical properties of vapor chopped and nonchopped Al 2O 3 thin films

Aluminium oxide being environmentally stable and having high transmittance is an interesting material for optoelectronics devices. Aluminium oxide thin films have been successfully deposited by hot water oxidation of vacuum evaporated aluminium thin films. The surface morphology, surface roughness, optical transmission, band gap, refractive index and intrinsic stress of Al 2O 3 thin films were studied. The cost effective vapor chopping technique was used. It was observed that, optical transmittance of vapor chopped Al 2O 3 thin film showed higher transmittance than the nonchopped film. The optical band gap of vapor chopped thin film was higher than the nonchopped Al 2O 3, whereas surface roughness and refractive index were lower due to vapor chopping.