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Showing papers on "Surface roughness published in 2012"


Journal ArticleDOI
TL;DR: In this paper, surface roughness-augmented wettability on critical heat flux (CHF) during pool boiling with horizontally oriented surfaces was investigated, and an analytical force-balance model was extended to explain the CHF enhancement.
Abstract: We experimentally investigated surface roughness-augmented wettability on critical heat flux (CHF) during pool boiling with horizontally oriented surfaces. Microstructured surfaces with a wide range of well-defined surface roughness were fabricated, and a maximum CHF of ∼208 W/cm2 was achieved with a surface roughness of ∼6. An analytical force-balance model was extended to explain the CHF enhancement. The excellent agreement found between the model and experimental data supports the idea that roughness-amplified capillary forces are responsible for the CHF enhancement on structured surfaces. The insights gained from this work suggest design guidelines for new surface technologies with high heat removal capability.

477 citations


Journal ArticleDOI
A. Baldan1
TL;DR: In this article, the authors reviewed the properties of the surfaces or interfaces of similar and dissimilar materials, adhesion or bonding mechanisms in the adhesive joints, surface tension or surface free energy concepts including the wetting, wetting criteria, wettability, and thermodynamic work of adhesion, dispersion and polar components of surface free energies, and finally the effect of surface roughness on wetability or adhesion.

354 citations


Journal ArticleDOI
TL;DR: A new realm of phonon scattering from rough interfaces is suggested, which restricts phonon transport below the Casimir limit and could aid the design of next generation thermoelectric devices.
Abstract: Although it has been qualitatively demonstrated that surface roughness can reduce the thermal conductivity of crystalline Si nanowires (SiNWs), the underlying reasons remain unknown and warrant quantitative studies and analysis. In this work, vapor–liquid–solid (VLS) grown SiNWs were controllably roughened and then thoroughly characterized with transmission electron microscopy to obtain detailed surface profiles. Once the roughness information (root-mean-square, σ, correlation length, L, and power spectra) was extracted from the surface profile of a specific SiNW, the thermal conductivity of the same SiNW was measured. The thermal conductivity correlated well with the power spectra of surface roughness, which varies as a power law in the 1–100 nm length scale range. These results suggest a new realm of phonon scattering from rough interfaces, which restricts phonon transport below the Casimir limit. Insights gained from this study can help develop a more concrete theoretical understanding of phonon–surfac...

295 citations


Journal ArticleDOI
TL;DR: An outline of the suite of roughness characterization parameters that are available for the comprehensive description of the surface architecture of a substratum is presented, and a set of topographical parameters is proposed as a new standard for surface Roughness characterization in bacterial adhesion studies to improve the likelihood of identifying direct relationships between substratum topography and the extent of bacterial ad cohesion.

295 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of cutting speed, feed rate, workpiece hardness and depth of cut on surface roughness and cutting force components in the hard turning were experimentally investigated.

287 citations


Journal ArticleDOI
TL;DR: Growth of nm-thick yttrium iron garnet films and ferromagnetic resonance (FMR) linewidth properties in the films were reported in this article, where films were grown on gadolinium gallium garnet substrates by pulsed laser deposition (PLD).
Abstract: Growth of nm-thick yttrium iron garnet films and ferromagnetic resonance (FMR) linewidth properties in the films are reported. The films were grown on gadolinium gallium garnet substrates by pulsed laser deposition (PLD). Films in the 5–35 nm thickness range showed a (111) orientation and a surface roughness between 0.1 and 0.3 nm. The 10 nm films showed a 10 GHz FMR linewidth of about 6 Oe and a damping constant of 3.2 × 10−4. The FMR linewidth increases with both the surface roughness and the surface Fe deficiency. Thicker films exhibit a smaller FMR linewidth and a lower damping constant.

261 citations


Journal ArticleDOI
TL;DR: The authors show that at high wind speeds white caps remain constant and at still higher wind speeds are joined, and increasingly dominated, by streaks of foam and spray, forming a white out, and the roughness begins to decrease and a high-velocity surface jet begins to develop.
Abstract: Waves breaking at the ocean surface are important to the dynamical, chemical and biological processes at the air-sea interface. The traditional view is that the white capping and aero-dynamical surface roughness increase with wind speed up to a limiting value. This view is fundamental to hurricane forecasting and climate research but it has never been verified at extreme winds. Here we show with observations that at high wind speeds white caps remain constant and at still higher wind speeds are joined, and increasingly dominated, by streaks of foam and spray. At surface wind speeds of ?40 m/s the streaks merge into a white out, the roughness begins to decrease and a high-velocity surface jet begins to develop. The roughness reduces to virtually zero by ?80 m/s wind speed, rendering the surface aero-dynamically extremely smooth in the most intense part of extreme (or major) hurricanes (wind speed > 50 m/s). A preliminary assessment shows that cross swell, dominant in large regions of hurricanes, allows the roughness under high wind conditions to increase considerably before it reduces to the same low values.

244 citations


Journal ArticleDOI
TL;DR: In this article, the correlation between surface roughness parameters and friction was investigated, and it was shown that surfaces with higher Sku and negative Ssk values tend to reduce friction.

238 citations


Journal ArticleDOI
TL;DR: Results showed that surfaces treated with HCl–HF–H3PO4 had higher roughness, lower cytotoxicity level and better biocompatibility than controls and addition of calcium chloride into mixed solution of three acids containing HCl, HF and H3 PO4 is an important, predominant and new technique for obtaining biofunction in metals for biomedical use including dentistry.
Abstract: Implant surface topography influences osteoblastic proliferation, differentiation and extracellular matrix protein expressions. Previous researches proved that chemical surface modification of titanium implants could be used to improve Bone-to-implant contact. In this study, the surface topography, chemistry and biocompatibility of polished titanium surfaces treated with mixed solution of three acids containing HCl, HF and H3PO4 with different etched conditions for example concentration, time and addition of calcium chloride were studied. Osteoblast cells (MG-63) were cultured on different groups of titanium surfaces. In order to investigate titanium surfaces, SEM, AFM and EDS analyses were carried out. The results showed that surfaces treated with HCl–HF–H3PO4 had higher roughness, lower cytotoxicity level and better biocompatibility than controls. Moreover, addition of calcium chloride into mixed solution of three acids containing HCl, HF and H3PO4 is an important, predominant and new technique for obtaining biofunction in metals for biomedical use including dentistry.

233 citations


Journal ArticleDOI
TL;DR: In this article, the effects of scan speed, layer thickness, and building direction on the following part features: dimensional error, surface roughness, and mechanical properties for DMLS with DS H20 powder and SLM with CL 20 powder (1.4404/AISI 316L).
Abstract: Rapid manufacturing is an advanced manufacturing technology based on layer-by-layer manufacturing to produce a part. This paper presents experimental work carried out to investigate the effects of scan speed, layer thickness, and building direction on the following part features: dimensional error, surface roughness, and mechanical properties for DMLS with DS H20 powder and SLM with CL 20 powder (1.4404/AISI 316L). Findings were evaluated using ANOVA analysis. According to the experimental results, build direction has a significant effect on part quality, in terms of dimensional error and surface roughness. For the SLM process, the build direction has no influence on mechanical properties. Results of this research support industry estimating part quality and mechanical properties before the production of parts with additive manufacturing, using iron-based powders.

232 citations


Journal ArticleDOI
TL;DR: In this paper, a novel surface modification of 3D titanium alloy-based open porous structures is developed, which applies a combination of chemical etching (CHE) and electrochemical polishing (ECP) using HF-based solutions.
Abstract: Additive manufacturing techniques can be used to produce micro-porous structures with global morphological properties that are highly controlled through robust computer design. Despite these advantages, most of these techniques still hold several functional constraints, resulting from present technical device limits and consequently the inability to control surface morphology at a microscale level. In this study, a novel protocol for surface modification of 3D titanium alloy-based open porous structures is developed, which applies a combination of chemical etching (CHE) and electrochemical polishing (ECP) using HF-based solutions. This protocol achieves significant and controllable roughness reduction of additive manufactured 3D Ti6Al4V open porous structures. Chemical etching mainly removes the attached powder grains, while ECP further decreases the roughness. In this way the heterogeneity of the strut surface roughness throughout the full 3D structure is effectively removed.

Journal ArticleDOI
TL;DR: In this article, the influence of cutting speed, feed rate and depth of cut on the surface roughness is examined, and the results indicate that the feed rate is the dominant factor affecting surface rougheness, which is minimized when the lowest level of cut is set, while the cutting speed is set to the highest level and the percentage of error all fall within 1% between the predicted values and the experimental values.

Journal ArticleDOI
TL;DR: In this paper, the impact of cutting parameters such as cutting speed, feed rate and depth of cut with machining force, power, specific cutting force, tool wear and surface roughness on work piece was established by multiple linear regression models.

Journal ArticleDOI
TL;DR: Through global interfacial energy analysis, it is revealed that, when the size of the evaporating droplet becomes comparable to the surface roughness, the line tension at the triple line becomes important in the prediction of the critical base size.
Abstract: Evaporation of a sessile droplet is a complex, nonequilibrium phenomenon. Although evaporating droplets upon superhydrophobic surfaces have been known to exhibit distinctive evaporation modes such as a constant contact line (CCL), a constant contact angle (CCA), or both, our fundamental understanding of the effects of surface roughness on the wetting transition remains elusive. We show that the onset time for the CCL-CCA transition and the critical base size at the Cassie-Wenzel transition exhibit remarkable dependence on the surface roughness. Through global interfacial energy analysis we reveal that, when the size of the evaporating droplet becomes comparable to the surface roughness, the line tension at the triple line becomes important in the prediction of the critical base size. Last, we show that both the CCL evaporation mode and the Cassie-Wenzel transition can be effectively inhibited by engineering a surface with hierarchical roughness.

Journal ArticleDOI
TL;DR: In this article, the influence of cutting speed, feed rate, depth of cut and machining time on machinability characteristics such as machining force, surface roughness and tool wear using response surface methodology (RSM) based second order mathematical models during turning of AISI 4340 high strength low alloy steel using coated carbide inserts.
Abstract: The hard turning process with advanced cutting tool materials has several advantages over grinding such as short cycle time, process flexibility, compatible surface roughness, higher material removal rate and less environment problems without the use of cutting fluid. However, the main concerns of hard turning are the cost of expensive tool materials and the effect of the process on machinability characteristics. The poor selection of the process parameters may cause excessive tool wear and increased work surface roughness. Hence, there is a need to study the machinability aspects in high-hardened components. In this work, an attempt has been made to analyze the influence of cutting speed, feed rate, depth of cut and machining time on machinability characteristics such as machining force, surface roughness and tool wear using response surface methodology (RSM) based second order mathematical models during turning of AISI 4340 high strength low alloy steel using coated carbide inserts. The experiments were planned as per full factorial design (FFD). From the parametric analysis, it is revealed that, the combination of low feed rate, low depth of cut and low machining time with high cutting speed is beneficial for minimizing the machining force and surface roughness. On the other hand, the interaction plots suggest that employing lower cutting speed with lower feed rate can reduce tool wear. Chip morphology study indicates the formation of various types of chips operating under several cutting conditions.

Journal ArticleDOI
TL;DR: In this article, the authors presented a complete analysis of the principal beneficial aspects produced by the application of ball-burnishing, which is an economical and feasible mechanical treatment for the quality improvement of rotating components, not only in surface roughness but in compressive residual stresses as well.
Abstract: In this article, deep ball-burnishing as a mechanical surface treatment for improving productivity and quality of rotating shafts is presented. When this technique is combined and applied after conventional turning, the resulting process is rapid, simple and cost-effective, directly applicable in lathes and turning centers of production lines. This process provides good surface finish, high compressive residual stresses, and hardness increment of the surface layer. These characteristics are the key for the fatigue life improvement of the component, and for wear resistance due to the higher hardness. This work presents a complete analysis of the principal beneficial aspects produced by the application of ball-burnishing. To determinate the influence of each process parameter, several tests were carried out. Once the optimum parameters were established, a complete analysis of the surface characteristics was performed. Surface topographies, sub-surface micro-hardness and residual stresses were measured. Complementary, a finite element model of ball-burnishing was used to understand and predict residual stress values and their variety with the process parameters. Results show that burnishing is an economical and feasible mechanical treatment for the quality improvement of rotating components, not only in surface roughness but in compressive residual stresses as well.

Journal ArticleDOI
TL;DR: In this article, the effect of physical and biological crusts on soil surface roughness and their influence on runoff and erosion was investigated, and the best relationship between microtopography and runoff on biologically crusted soils was found for surface storage capacity, which appears as a powerful predictor of the runoff coefficient on long temporal scales.

Journal ArticleDOI
TL;DR: In this paper, a nano-cutting fluid is made by adding 1% Al2O3 nanoparticles to conventional cutting fluid and the wettability characteristic of this nano cutting fluid on a carbide tool tip is measured using the macroscopic contact angle method.
Abstract: Nano-cutting fluids are the mixtures of conventional cutting fluid and nanoparticles. Addition of the nanoparticles can alter wettability, lubricating properties, and convective heat transfer coefficient (cooling properties) of nano-cutting fluids. In the present work, nano-cutting fluid is made by adding 1% Al2O3 nanoparticles to conventional cutting fluid. The wettability characteristic of this nano-cutting fluid on a carbide tool tip is measured using the macroscopic contact angle method. Comparative study of tool wear, cutting force, workpiece surface roughness, and chip thickness among dry machining, machining with conventional cutting fluid as well as nano-cutting fluid has been undertaken. This study clearly reveals that the cutting force, workpiece surface roughness, tool wear, and chip thickness are reduced by the using nano-cutting fluid compared to dry machining and machining with conventional cutting fluid.

Journal ArticleDOI
15 May 2012-Wear
TL;DR: In this article, the authors demonstrate the process of making micro-dimples by ultrasonic nanocrystalline surface modification (UNSM) technology and evaluate its effects on tribological characteristics.

Journal ArticleDOI
TL;DR: A method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance is presented, and new insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the Stainless steel surfaces.
Abstract: In this work, we present a method to render stainless steel surfaces superhydrophobic while maintaining their corrosion resistance. Creation of surface roughness on 304 and 316 grade stainless steels was performed using a hydrofluoric acid bath. New insight into the etch process is developed through a detailed analysis of the chemical and physical changes that occur on the stainless steel surfaces. As a result of intergranular corrosion, along with metallic oxide and fluoride redeposition, surface roughness was generated on the nano- and microscales. Differences in alloy composition between 304 and 316 grades of stainless steel led to variations in etch rate and different levels of surface roughness for similar etch times. After fluorocarbon film deposition to lower the surface energy, etched samples of 304 and 316 stainless steel displayed maximum static water contact angles of 159.9 and 146.6°, respectively. However, etching in HF also caused both grades of stainless steel to be susceptible to corrosion. By passivating the HF-etched samples in a nitric acid bath, the corrosion resistant properties of stainless steels were recovered. When a three step process was used, consisting of etching, passivation and fluorocarbon deposition, 304 and 316 stainless steel samples exhibited maximum contact angles of 157.3 and 134.9°, respectively, while maintaining corrosion resistance.

Journal ArticleDOI
TL;DR: In this article, the evaporation of water sessile droplets on hydrophobised silicon wafers and Teflon was analyzed from theoretical and experimental perspectives using tensiometry.

Journal ArticleDOI
TL;DR: In this article, the authors calculate the band-limited relevant roughness from surface metrology data, then present parametric plots of the TIS for optical surfaces with arbitrary roughness, surface correlation widths, and incident angles.
Abstract: Surface scatter effects from residual optical fabrication errors can severely degrade optical performance. The total integrated scatter (TIS) from a given mirror surface is determined by the ratio of the spatial frequency band-limited "relevant" root-mean-square surface roughness to the wavelength of light. For short-wavelength (extreme-ultraviolet/x-ray) applications, even state-of-the-art optical surfaces can scatter a significant fraction of the total reflected light. In this paper we first discuss how to calculate the band-limited relevant roughness from surface metrology data, then present parametric plots of the TIS for optical surfaces with arbitrary roughness, surface correlation widths, and incident angles. Surfaces with both Gaussian and ABC or K-correlation power spectral density functions have been modeled. These parametric TIS predictions provide insight that is useful in determining realistic optical fabrication tolerances necessary to satisfy specific optical performance requirements.

Journal ArticleDOI
TL;DR: In this article, the authors performed a comprehensive study of microscale water condensation dynamics on nanostructured superhydrophobic surfaces made using a variety of synthetic methods and demonstrated that the growth mechanism of individual water microdroplets on these surfaces is universal and independent of the surface architecture.
Abstract: Nanostructured surfaces which manifest superhydrophobic properties during water condensation have a potential to dramatically enhance energy efficiency in power generation and desalination systems. Although various such surfaces have been reported, their development has been fortuitous, not driven by an understanding of the underlying physical processes. In this work, we perform a comprehensive study of microscale water condensation dynamics on nanostructured superhydrophobic surfaces made using a variety of synthetic methods. We demonstrate that the growth mechanism of individual water microdroplets on these surfaces is universal and independent of the surface architecture. The key role of the nanoscale topography is confinement of the base area of forming droplets, which allows droplets to grow only through contact angle increase. The nearly spherical droplets formed in this fashion become highly mobile after coalescence. By comparing experimentally observed drop growth with interface free energy calculations, we show that the minimum observed confined microdroplet base diameter depends directly on the nanoscale surface roughness and degree of interfacial wetting. Specifically, we show that the microscale condensation mechanism depends on the height of a liquid film with volume equal to the fill volume between the nanostructures. This introduced roughness length scale is a universal metric that allows for facile comparison of arbitrarily complex surface architectures. We use this new fundamental insight to develop quantitative design guidelines for superhydrophobic surfaces intended for condensation applications.

Journal ArticleDOI
TL;DR: While the Sof-Lex discs provided the lowest surface roughness, the Enhance Polishing system provided the most stain-resistant groups and showed the lowest color differences among all the finishing systems.

Journal ArticleDOI
TL;DR: In this paper, a mathematical model based on response surface methodology (RSM) is developed to study the variation of surface roughness with changing process parameter settings of the EBM system.
Abstract: Purpose – Ti‐6Al‐4V is one of the most attractive materials being used in aerospace, automotive and medical implant industries. Electron beam melting (EBM) is one of the direct digital manufacturing methods to produce complex geometries of fully dense and near net shape parts. The EBM system provides an opportunity to built metallic objects with different processing parameter settings like beam current, scan speed, probe size on powder, etc. The purpose of this paper is to determine and understand the effect of part's thickness and variation in process parameter settings of the EBM system on surface roughness/topography of EBM fabricated Ti‐6Al‐4V metallic parts.Design/methodology/approach – A mathematical model based upon response surface methodology (RSM) is developed to study the variation of surface roughness with changing process parameter settings. Surface roughness of the test slabs produced with different parameter settings and thickness has been studied under confocal microscope. Response surface...

Journal ArticleDOI
TL;DR: In this paper, the authors quantify the water permeability of localized cracks as a function of crack geometry (i.e., width, tortuosity, and surface roughness).

Journal ArticleDOI
TL;DR: Three different type of support vector machines (SVMs) tools such as least square SVM, Spider SVM and SVM-KM and an artificial neural network model and an feedforward neural network were developed to estimate the surface roughness values of AISI 304 austenitic stainless steel in CNC turning operation.
Abstract: In the present investigation, three different type of support vector machines (SVMs) tools such as least square SVM (LS-SVM), Spider SVM and SVM-KM and an artificial neural network (ANN) model were developed to estimate the surface roughness values of AISI 304 austenitic stainless steel in CNC turning operation. In the development of predictive models, turning parameters of cutting speed, feed rate and depth of cut were considered as model variables. For this purpose, a three-level full factorial design of experiments (DOE) method was used to collect surface roughness values. A feedforward neural network based on backpropagation algorithm was a multilayered architecture made up of 15 hidden neurons placed between input and output layers. The prediction results showed that the all used SVMs results were better than ANN with high correlations between the prediction and experimentally measured values.

Journal ArticleDOI
TL;DR: In this paper, both TiO 2 and SiO 2 coated steel surfaces containing micro-and nanoscale binary structures with different surface roughness were successfully fabricated by means of a facile layer by layer deposition process followed by heat treatment.

Journal ArticleDOI
TL;DR: In this paper, a machinability study on flank wear, surface roughness, chip morphology and cutting forces in finish hard turning of AISI 4340 steel using uncoated and multilayer TiN and ZrCN coated carbide inserts at higher cutting speed range.

Journal ArticleDOI
TL;DR: In this article, a surface of epoxy-impregnated hardened cement paste was investigated using a novel atomic force microscopy (AFM) imaging mode that allows for the quantitative mapping of the local elastic modulus.