Surface Roughness Factor Research Articles

Comprehensive study on machinability of sustainable and conventional fibre reinforced polymer composites

The conventional homogeneous materials can no longer effectively satisfy the growing demands on product capabilities and performance, due to the advancement in products design and materials engineering. Therefore, the fibre reinforced composites (FRCs) with better properties and desirable applications emerged. These enhanced qualities of the FRCs have emphasized the need for analysing their machinability for further improvement of performance. Hence, this paper presents a comprehensive investigation on the machinability effects of drilling parameters (feed rate, cutting speed and thrust force), drill diameters and chips formation mainly on delamination and surface roughness of hemp fibre reinforced polymer (19/HFRP) and carbon fibre reinforced polymer (MTM 44-1/CFRP) composite laminates, using high speed steel (HSS) drills under dry machining condition. The results obtained depict that an increase in feed rate and thrust force caused an increase in delamination and surface roughness of both samples, different from cutting speed. Also, increased drill diameter and types of chips formation caused an increase in both delamination and surface roughness of both samples, as the material removal rate (MRR) increased. Evidently, the minimum surface roughness and delamination factor of the two samples for an optimal drilling are associated with feed rates of 0.05–0.10mm/rev and cutting speed of 30m/min.

Evolution of N-Coordinated Iron–Carbon (FeNC) Catalysts and Their Oxygen Reduction (ORR) Performance in Acidic Media at Various Stages of Catalyst Synthesis: An Attempt at Benchmarking

The objective of this study was to understand the role of iron and the heat treatment steps involved in nitrogen-coordinated iron-carbon (FeNC) catalyst synthesis. We have studied the oxygen reduction reaction (ORR) performance of these catalysts as they evolve from their most crude and inactive form to their most active form. Electrochemical half-cell and fuel cell tests suggest that the presence of Fe was crucial in these samples. The high-temperature heat treatment (once in argon and then in ammonia) at temperatures ≥950 °C were also critical in imparting these catalysts with their highest activity; however, significant loss of activity was observed with cycling and potential hold at 0.5 V for 100 h. In addition, acid-washing after the first or the second pyrolysis steps produced a marked decrease in ORR activity relative to their unwashed counterparts. We also report findings from our efforts towards benchmarking FeNC catalysts for oxygen reduction reaction electrocatalysis. Specifically, we focus on correlating the specific kinetic current (iK) at 0.75 V to electrochemically accessible surface area (EASA) and roughness factor (RF) determined from electrochemical double layer capacitance measurements. 57Fe Mossbauer spectroscopy was employed to shed light into the nature of active sites in FeNC catalysts and provide insights into their deactivation behavior caused by acid-washing. The results suggest planar FeN4 doublet (Fe2+, low spin) as an active site in these materials, which may be leached away in acid, explaining their decreased activity after acid washing. Results for characterization experiments using X-ray photoelectron spectroscopy, temperature programmed oxidation and X-ray absorption spectroscopy, superconducting quantum interference device magnetometry are also presented.

Dependence of morphology on anionic flotation of alumina

Morphological features of particles upon size reduction affect flotation recoveries in terms of kinetics, bubble-particle interactions and even suspension properties. The significance of surface roughness and shape factor of particles on flotation recovery and their underlying mechanism has been shown to be of importance. Towards this aim, a series of micro-flotation tests have been performed with original, ground and ground-abraded alumina particles in the presence of sodium dodecyl sulfate collector in order to demonstrate the influence of morphological features on flotation recoveries. The flotation results are discussed with the help of literature data on shape and roughness of various types of particles.

Evolution and equivalent control law of surface roughness in shear-thickening polishing

A comprehensive surface roughness model is established to predict the average surface roughness achieved by shear-thickening polishing (STP) based on calculation of Brinell hardness number (BHN), shear-thickening mechanism and plastic indentation on abrasive wear theory. The model takes the effects of material hardness and plastic wear into account in addition to the calculation of the surface roughness factors concerning the normal pressure, slurry performance, et al. The “size effect” as the ratio of abrasive size to solid colloidal particle size, has also been successfully integrated into the model. STP experiments validate that the maximal difference of surface roughness between theoretical and experimental results is no greater than 12.02%. The surface evolution process can be theoretically and experimentally described with certain feasibility and veracity. An inflection point appears in the trend line of predicted surface roughness when the ratio approaches to 0.5. An equivalent control law of surface roughness in STP exists when the ratio is greater than 0.5 and is revealed by the model and experiments due to the competing effects of kinematics, indentation depth, cutting width, plastic plowing of materials on surface formation. The freedom control for an invariable surface roughness can be achieved by STP according to the equivalent control law. The prediction model for brittle materials shall be revised based on material properties and more removal forms.

Experimental investigation of machinability characteristics in Al-TiB2metal matrix composite (MMC) based on the Taguchi method with fuzzy logics

Purpose– The purpose of this paper is to develop a mathematical model for metal removal rate and surface roughness through Taguchi method and analyse the influence of the individual input machining parameters (cutting speed, feed rate, helix angle, depth of cut and wt% on the responses in milling of aluminium-titanium diboride metal matrix composite (MMC) with solid carbide end mill cutter coated with nano-crystals.Design/methodology/approach– Taguchi OA is used to optimise the material removal rate (MRR) and Surface Roughness by developing a mathematical model. End Milling is used to create slots by combining various input parameters. Five factors, three-level Taguchi method is employed to carry out the experimental investigation. Fuzzy logic is used to find the optimal cutting factors for surface roughness (Ra) and MRR. The factors considered were weight percentage of TiB2, cutting speed, depth of cut and feed rate. The plan for the experiments and analysis was based on the Taguchi L27 orthogonal array with five factors and three levels. MINITAB 17 software is used for regression, S/N ratio and analysis of variance. MATLAB 7.10.0 is used to perform the fuzzy logics systems.Findings– Using fuzzy logics, multi-response performance index is generated, with which the authors can identify the correct combination of input parameters to get higher MRR and lower surface roughness value with the chosen range with 95 per cent confidence intervals. Using such a model, remarkable savings in time and cost can be obtained.Originality/value– Machinability characteristics in Al-TiB2MMC based on the Taguchi method with fuzzy logic has not been analysed previously.

Effects of coating process on the surface roughness of coated fabrics

Roughness of textiles and garments is an important parameter influencing consumer choice. This work considers the effect of applying a polyurethane coating on the surface roughness of woven polymer fabrics. A number of different process parameters were tested, including curing temperature, gap spacing, coating speed and viscosity of the coating paste. The Kawabata Evaluation System for Fabrics (KESF) was used to measure fabric surface roughness. By selecting appropriate process parameters, coatings with low roughness can be obtained. We show that, fabric type and microstructure are the major determining factors of surface roughness. Our multivariable testing also revealed a complex and nonlinear correlation between the thickness of coatings and their surface roughness, which we explain invoking a physical mechanism which takes into account the microscale interactions between fabric filaments and the coating paste that occur throughout the curing process.

Fatigue Life Prediction of Screw Blade in Screw Sand Washing Machine under Random Load with Gauss Distribution

The purpose of this study is to present a new method for estimating the fatigue life of the screw blade in the screw sand washing machine. To ensure the accuracy of numerical simulation, the loading area and the value of load are determined by means of the theoretical analysis. To ascertain the location of the stress peak and stress range, the static analysis of the screw blade is executed via the finite element method. To reduce the research cost and ensure the feasibility of the research method, Markov chain Monte Carlo (MCMC) is employed to simulate the random load with the Gauss distribution on the screw blade. In addition, the Nondominated Sorting Genetic Algorithm (NSGA-II) is utilized to find out an optimum variation coefficient of the stress, aiming at guaranteeing the precision of the random load. The rainflow cycle extrapolation is adopted to generate the fatigue load spectrum closer to the real condition, taking account of the possibility of the extreme loads caused by overload occurrence. Subsequently, the rainflow matrix after extrapolation, the estimated P-S-N curve, Goodman stress correction method and Miner's rules are made use of assessing the service life of the screw blade. In particular, the effects of the surface roughness, residual stresses and fatigue notch factors on the fatigue life are taken into consideration. Ultimately, the non-linear surface fitting technique is used to obtain the equation concerning the fatigue life of the screw blade versus residual stresses and fatigue notch factors. The numerical results show that the stress peak is in the root of the screw blade and the service life of the screw blade declines exponentially with growing residual stresses and fatigue notch factors.

The algorithm of accelerated cracks detection and extracting skeleton by direction chain code in concrete surface image

Due to concrete surface roughness, uneven illumination, shadows, complex background and other disruptive factors, the traditional image processing-based concrete crack detection method cannot accurately detect concrete cracks, especially unclear ones and some tiny ones. The crack detection method based on the percolation model, which fully considered the low brightness and slenderness of the cracks, can accurately detect unclear and tiny cracks. But this method is time-consuming, and in some cases, it may cause fractures on the detected cracks. In order to solve these problems, this paper proposed an improved algorithm of image crack inspection based on the percolation model, which can reduce processing time through reducing the number of percolated pixels. To reconnect the fractured cracks, this method extracts the skeleton of cracks first by using an algorithm of skeleton extraction based on direction chain code. Then this paper proposed a region extension-based algorithm to reconnect part of the fractured cracks. Experimental results showed that this algorithm can significantly accelerate crack detection and maintain high detection precision.

The influence of boundary conditions on the electrical conductivity of a thin cylindrical wire

Within the kinetic approach, the high-frequency electrical conductivity of a thin semiconductor circular cross-section wire is calculated. The radius of the wire is assumed to be small compared with the characteristic skin depth that allows neglecting the skin effect. A model taking into account the dependence of the reflectivity coefficient on the surface roughness factor and the angle of incidence of the charge carriers at the inner border of the wire was used as the boundary conditions for the nonequilibrium distribution function of the charge carriers The extreme cases of a degenerate semiconductor and a nondegenerate one are considered. The results obtained are compared to the calculations for the model of Fuchs diffuse-specular boundary conditions.

Environmental effectiveness of GAEC cross-compliance standard 1.1c ‘Maintenance of farm channel networks and field convexity’ and economic evaluation of the competitiveness gap for farmers

This paper shows the results of the monitoring carried out in three farms of the project MO.NA.CO. in order to verify the effectiveness of the cross-compliance standard 1.1c which obliges the farmer to the ‘Maintenance of farm channel networks and field convexity’ in order to ensure its efficiency and functionality in draining water. It was also examined the competitiveness gap induced to the agricultural enterprise by the application of the standard, that is to say the additional costs borne by the beneficiary of the single payment determined by cleaning farm collector channels. Effectiveness was determined by evaluating the degradation of soil structure at the end of winter, on flat fields  sown in autumn with winter wheat, in the two cases: a) Factual (channels along the field edges not clogged and no waterlogging present on the cultivated soil) b) Counterfactual (channels clogged and waterlogging present on the cultivated soil). The monitoring confirmed a positive effect of the adoption of this standard on predisposing soil to the ideal conditions for the maintenance of the structure. Despite the statistical evidence found, it must be said that the change in the surface roughness factor was so small as not to take any practical significance in order to affirm that the functional maintenance of collectors channels have been effective in reducing erosion. Overall, the soils were unstructured and crusted at the end of the observation period. Indexes Icli, NTU, and DS show a structural fragility from medium to high for soils of the three monitoring farms. This explains the lack of appreciable differences in the soil roughness parameter, especially in relation to   heavy rains and long waterlogging periods in the cropping years of monitoring. The competitiveness gap induced by the application of this standard, amounted to 19.89±€ 6.35 ha-1 year-1. Atmospheric emission of CO2, was equal to 14.53±6.62 kg ha-1 year-1. It is considered important to point out that at the present Annex II: ‘Rules of cross-compliance’ of Regulation (EU) No. 1306/2013 includes a BCAA not taking into account the environmental threats determined by waterlogging in cultivated land to soil, crops and to atmosphere, due to the possible production of greenhouse gases. As regards the infringement criteria to the standard it is suggested the introduction of the verification of the presence of convexity on cultivated fields in the plain.

Design of a superhydrophobic and superoleophilic film using cured fluoropolymer@silica hybrid

Recently, considerable efforts have been made on superhydrophobic–superoleophilic filter to satisfy the requirements of the applications to oil/water separation. In this work, we obtained a superhydrophobic and superoleophilic film by coating cured fluoropolymer@silica hybrid on stainless steel mesh. Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric-differential scanning calorimetry (TG-DSC) were used to determine the chemical composition and thermal stability of the sample. The effect of silica nanoparticles (NPs) concentration on the surface property of the hybrid film was analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle analyzer. The results indicate that silica NPs not only enhance the thermal stability, but also strengthen the hydrophobicity and oleophilicity of the film. When 20wt% silica NPs was added into the thermosetting fluoropolymer, the hybrid film shows both superhydrophobicity and superoleophilicity owing to the large surface roughness factor (RMS) and porous structure. Moreover, the hybrid film could be used to separate water from different oils effectively. When the pore size of the mesh is less than 300μm, the oil/water separation efficiency of the film reaches above 99%, which shows a great potential application to dehydrate fuel oils.

Identification of flexible vehicle parameters on bridge using particle filter method

A conditional probability based approach known as Particle Filter Method (PFM) is a powerful tool for system parameter identification. In this paper, PFM has been applied to identify the vehicle parameters based on response statistics of the bridge. The flexibility of vehicle model has been considered in the formulation of bridge-vehicle interaction dynamics. The random unevenness of bridge has been idealized as non homogeneous random process in space. The simulated response has been contaminated with artificial noise to reflect the field condition. The performance of the identification system has been examined for various measurement location, vehicle velocity, bridge surface roughness factor, noise level and assumption of prior probability density. Identified vehicle parameters are found reasonably accurate and reconstructed interactive force time history with identified parameters closely matches with the simulated results. The study also reveals that crude assumption of prior probability density function does not end up with an incorrect estimate of parameters except requiring longer time for the iterative process to converge.

Experimental Study on the Surface Roughness in Mesoscopic-Scale Grinding of Nickel-Based Superalloy

This paper uses micro-grinding tool with 500# grains and 0.9 mm diameter to grind nickel-based superalloy Inconel600 through three factors(grinding depth, feed rate, spindle speed ) at three levels orthogonal grinding experiment in mesoscopic scale. Then according to the range analysis of surface roughness, the primary and secondary influencial factors are found; the micro grinding parameters are optimized ,the results show: the influence of the feed rate(vf)is the biggest, followed by the spindle speed(n), the grinding depth(ap) is minimal, when n=50kr/min, vf=100μm/s, ap=6μm, the grinding surface roughness is minimum: Ra=579nm; finally , the regression mathematical model of micro grinding surface roughness is established, the relative error of the calculated value and experimental measurements is low, showing that this regression mathematical model is accurate and effective. This study provides a theoretical basis for the micro grinding parameters and surface quality control of nickel-based superally.

Effect of cutting parameters on machinability characteristics in milling of magnesium alloy with carbide tool

Magnesium alloy has attracted more attentions due to its excellent mechanical properties. However, in process of dry cutting operation, many problems restrict its further development. In this article, the effect of cutting parameters on machinabilities of magnesium alloy is explored under dry milling condition. This research is an attempt to investigate the impact of cutting speed at multiple feed rates on cutting force and surface roughness, while a statistical analysis is adopted to determine the influential intensities accurately. The results showed that cutting force is affected by the positively constant intensity from feed rate and the increasingly negative intensity from cutting speed. In contrast, surface roughness is determined by the gradually increasing negative tendency from feed rate and the positive effect with constant intensity from cutting speed. Within the range of the experiments, feed rate is the leading contribution for cutting force while the cutting speed is the dominant factor for surface roughness according to the absolute intensity values. Meanwhile, the trends of influencing intensities between cutting force and surface roughness are opposite. Besides, it is also found that in milling magnesium alloy, chip morphology is highly sensitive to cutting speed while the chip quality mainly depends on feed rate.

Effect of roughness and shape factor on flotation characteristics of glass beads

Abstract The effect of surface roughness and shape factor on behavior of particles in flotation has been investigated. Surface roughness of various degrees was applied on spherical glass beads of −150 +106 μm by means of acid etching. The same procedure was also performed on ground glass beads of the same size interval with different shape factors. The effect of these variations on surface morphology of particles was investigated in terms of flotation recovery, contact angle, and bubble-particle attachment. An Atomic Force Microscope (AFM) was used for surface roughness characterizations and a correction methodology on roughness measurements of spherical particles is proposed. A digital image analyzer was used for shape factor characterizations. It is shown that increase in surface roughness improves the flotation recovery, contact angle, and bubble attachment. Shape factor, however, was found to be more predominant in flotation and bubble attachment. This is attributed to the effect of sharp edges of ground particles which triggers the film rupture process and shortens the attachment time.

Measurement and optimization of surface roughness and tool wear via grey relational analysis, TOPSIS and RSA techniques

Magnesium alloy (Mg alloy) is one among the lightest materials and which has wide applications in the production of aircraft engines, airframes, helicopter components, light trucks, automotive parts and computers parts for its attractive properties. In this paper, a study to analyze the turning properties of magnesium alloy AZ91D in dry condition with polycrystalline diamond (PCD) cutting inserts is presented. Firstly, to investigate turning of magnesium alloy using grey relational analysis and TOPSIS of optimum cutting parameter values. Secondly, to determine using response surface analysis of mathematical model depending on cutting parameters of surface roughness and tool flank wear in turning. The adequacy of the developed mathematical model is proved by ANOVA. The findings from the investigation showed that feed rate and cutting speed are the dominant factors for surface roughness and tool flank wear respectively.

Experimental Research of Wetting and Drop Evaporation Processes on a Heated Substrate as a Method for Research Skills Development for Heat and Power Engineering Students

The article considers a method used for student research competency development during the course “Process energy sources for industrial facilities” in Tomsk Polytechnic University. The experiment is based on shadow and Schlieren optical methods for observing the water drop evaporation on the solid surface. Using the images obtained by plane-parallel light during the evaporation process and Drop Shape analyses software, students are to determine the drop's geometric parameters. After the experiment and results processing, they are required to determine the evaporation stages, study effects of surface roughness and temperature factors on characteristics of drop spreading (contact angle and diameter).

Oxygen bubble–templated anodic deposition of porous PbO 2

The oxygen bubble–templated deposition of porous PbO2 was realized by anodizing Pb(II) solutions (in nitrate-acetate, sulfamate or methanesulfonate media) at large current density. This process is the anodic analogue of the more common hydrogen bubble–templated electrodeposition of porous metals. The porous PbO2 layers consisted of a mixture of α- and β-phases, in contrast to compact layers deposited at low current density (pure α-PbO2). The void volume fraction and surface roughness factor of porous PbO2 were estimated.

Kinetics of gypsum dissolution in water

The kinetics of dissolution of different lithological varieties of gypsum was experimentally investigated at 5–25°C and P = 0.1 MPa, and a simple rate model was proposed on the basis of the sum of the rates of forward and backward reactions and proportionality to the activity product of calcium and sulfate ions. The activation energies of the forward reaction correspond to dissolution controlled by surface reaction kinetics. It was shown that the kinetic parameters of gypsum dissolution are invariant to the initial concentrations of NaCl solutions (up to 2 M). It was shown that the surface roughness factor (ξ) depends on the chemical composition of lithological varieties and the average grain size of gypsum and changes during epigenetic processes. The obtained kinetic parameters of gypsum dissolution in water will be used for the calculation of groundwater-driven mass transfer.

Enzymeless glucose sensor integrated with chronically implantable nerve cuff electrode for in-situ inflammation monitoring

Using glucose concentration as an inflammation responsive element, we newly established an enzymeless glucose sensor integrated with a chronically implantable peripheral nerve cuff electrode for continuous and in-situ monitoring of local inflammation. The glucose sensor integrated with a nerve cuff electrode was fabricated on a polyimide substrate side-by-side, then the glucose sensor and nerve cuff electrode were reversely folded, and were located inside and outside, respectively. The experimental results reveal that the electroplated black Pt working electrode of the glucose sensor shows an enhancive surface roughness factor of 16.41 and had a good distribution on the flexible polyimide surface, which exhibits distinctly enhanced electro-catalytic activity compared to that obtained with plain Pt. Amperometry and electrochemical impedance spectroscopy indicated that the fabricated sensor had a sensitivity of 7.17μA/mMcm2, an outstanding detection limit of 10μM, significant selectivity, and excellent recovery performance for enzymeless glucose detection. In order to evaluate the feasibility for inflammation monitoring in the immediate vicinity of the implantable peripheral nerve cuff electrode, the association of an evoked nerve signal recording and glucose concentration was investigated through ex-vivo test using the sciatic nerve of a SD rat.