Surface Roughness Factor Research Articles

Multi-objective optimization in end milling of GFRP composites using Taguchi techniques with principal component analysis

PurposeThe purpose of this paper is to find out the optimum machining parameters using Taguchi technique with principal component analysis (PCA) during end milling of GFRP composites.Design/methodology/approachIn multi-objective optimization, weight criteria of each objective are important for producing better and accurate solutions. This method has been employed for simultaneous minimization of surface roughness, cutting force and delamination factor. Experiments were planned using Taguchi’s orthogonal array with the machining parameters, namely, helix angle of the end mill cutter, spindle speed, feed rate and depth of cut were optimized with considerations of multiple response characteristics, including machining force, surface roughness and delamination as the responses. PCA is adopted to find the weight factors involved for all objectives. Finally analysis of variance concept is employed on multi-SN ratio to find out the relative significance of machining parameter in terms of their percentage contribution.FindingsThe multi-SN ratio is achieved by the product of weight factor and SN ratio to the performance characteristics in the utility concept. The results show that a combination of machining parameters for the optimized results has helix angle of 35°, machining speed of 4,000 m/min, feed rate of 750 mm/rev and depth of cut of 2.0 mm.Originality/valueEffect of milling of GFRP composites on delamination factor, surface roughness and machining force with various helix angle solid carbide end mill has not been analysed yet using PCA techniques.

Electrochemical Behavior of a Pd Thin Film Electrode in Concentrated Alkaline Media

Pd limited volume electrodes (LVE) were obtained electrochemically from the PdCl2 aqueous solution. Hydrogen absorption was performed using cyclic voltammetry and chronoamperometry in concentrated (6 M) alkaline solutions (KOH, NaOH, the mixture of 2M LiOH + 4M KOH) and results were compared with 0.5 M H2SO4. It was found that hydrogen pretreatment procedure is crucial for further examination of hydrogen absorption in Pd electrodes. After many cycles of hydrogen absorption/desorption in Pd, these processes become electrochemically more reversible—faster than in a freshly prepared electrode. Results obtained for Pd electrodes in different concentrated alkaline media subjected to hydrogen pretreatment procedure are comparable with those for an acidic solution (e.g., α→β phase transition potential equals to ca. 0.050 V vs. RHE). The continuous Pd electrode cycling does not affect significantly the amount of absorbed hydrogen (ca. 0.72–0.74). The surface roughness factor in basic solutions decreases after multiple hydrogen sorption as in case of an acidic solution.Graphical ᅟ

Fabrication of nanoporous gold thin films on glass substrates for amperometric sensing of aniline

Nanoporous gold (NP-Au) thin films were fabricated on glass substrates by dealloying an Au–Si alloy produced by co-deposition of Au and Si. Si was selectively removed from the Au–Si alloy with potassium hydroxide solution, which is a very simple and safe dealloying method. We investigated the optimum conditions for sputtering and dealloying to obtain stable and durable nanoporous films. The NP-Au films were used as a working electrode for amperometric sensing of aniline in water and exhibited a wider sensing range and lower detection limit than NP-Au electrodes fabricated on Si substrates with HF etchant. The larger surface roughness factor of the NP-Au sensor is responsible for the enhanced sensing performance.

Surface Soil Moisture Retrieval Using the L-Band Synthetic Aperture Radar Onboard the Soil Moisture Active-Passive Satellite and Evaluation at Core Validation Sites.

This paper evaluates the retrieval of soil moisture in the top 5-cm layer at 3-km spatial resolution using L-band dual-copolarized Soil Moisture Active-Passive (SMAP) synthetic aperture radar (SAR) data that mapped the globe every three days from mid-April to early July, 2015. Surface soil moisture retrievals using radar observations have been challenging in the past due to complicating factors of surface roughness and vegetation scattering. Here, physically based forward models of radar scattering for individual vegetation types are inverted using a time-series approach to retrieve soil moisture while correcting for the effects of static roughness and dynamic vegetation. Compared with the past studies in homogeneous field scales, this paper performs a stringent test with the satellite data in the presence of terrain slope, subpixel heterogeneity, and vegetation growth. The retrieval process also addresses any deficiencies in the forward model by removing any time-averaged bias between model and observations and by adjusting the strength of vegetation contributions. The retrievals are assessed at 14 core validation sites representing a wide range of global soil and vegetation conditions over grass, pasture, shrub, woody savanna, corn, wheat, and soybean fields. The predictions of the forward models used agree with SMAP measurements to within 0.5 dB unbiased-root-mean-square error (ubRMSE) and -0.05 dB (bias) for both copolarizations. Soil moisture retrievals have an accuracy of 0.052 m3/m3 ubRMSE, -0.015 m3/m3 bias, and a correlation of 0.50, compared to in situ measurements, thus meeting the accuracy target of 0.06 m3/m3 ubRMSE. The successful retrieval demonstrates the feasibility of a physically based time series retrieval with L-band SAR data for characterizing soil moisture over diverse conditions of soil moisture, surface roughness, and vegetation.

Machining process influence on the chip form and surface roughness by neuro-fuzzy technique

The main aim of the study was to analyze the influence of six machining parameters on the chip shape formation and surface roughness as well during turning of Steel 30CrNiMo8. Three components of cutting forces were used as inputs together with cutting speed, feed rate, and depth of cut. It is crucial for the engineers to use optimal machining parameters to get the best results or to high control of the machining process. Therefore, there is need to find the machining parameters for the optimal procedure of the machining process. Adaptive neuro-fuzzy inference system (ANFIS) was used to estimate the inputs influence on the chip shape formation and surface roughness. According to the results, the cutting force in direction of the depth of cut has the highest influence on the chip form. The testing error for the cutting force in direction of the depth of cut has testing error 0.2562. This cutting force determines the depth of cut. According to the results, the depth of cut has the highest influence on the surface roughness. Also the depth of cut has the highest influence on the surface roughness. The testing error for the cutting force in direction of the depth of cut has testing error 5.2753. Generally the depth of cut and the cutting force which provides the depth of cut are the most dominant factors for chip forms and surface roughness. Any small changes in depth of cut or in cutting force which provide the depth of cut could drastically affect the chip form or surface roughness of the working material.

Optimization of Milling Carbon Fibre Reinforced Plastic Using RSM

Carbon Fibre Reinforced Plastic (CFRP) is extensively used nowadays especially in the industries due to its desirable properties of high strength, light weight and high resistance to corrosion. However, the machining of CFRP composites requires great specification and requirement as it is difficult to be machine. Besides, improper technique and parameters used to machine CFRP may result in poor surface quality such as high surface roughness and delamination. This study was done on a CFRP panel with solid uncoated carbide tool with diameter of 8mm was used as cutting tool. Thus, this project investigates the influence of the cutting parameters which are spindle speed, feed rate and depth of cut to the surface quality of the CFRP by undergoing milling operation. The cutting parameters used during the milling operation of the CFRP panel ranged from 500rpm to 3500rpm for the cutting speed, feed rate from 100mm/min to 900mm/min and lastly 0.5mm to 2.0mm range for depth of cut. 15 runs of experiments is performed based on the Central Composite Design (CCD) of Response Surface Methodology. Through this study, the optimum cutting parameters during milling of CFRP is determined and the main factors affecting the surface quality are also highlighted. Based on the developed mathematical model, the feed rate was identified as the primary significant parameter that influenced surface roughness and delamination. In conclusion, the influence of the cutting parameters on the CFRP panel is higher cutting speed, lower feed rate and lower depth of cut resulted in low surface roughness and delamination factor. Feed rate was identified to be the primary significant cutting parameter that contributes to low surface roughness and delamination factor. The optimized cutting parameters were cutting speed, feed rate and depth of cut of 3061rpm, 211.34mm/min and 0.72mm respectively with surface roughness of 1.34 um and delamination factor of 1.08.

Galvanostatic Intermittent Titration and Performance Based Analysis of LiNi0.5Co0.2Mn0.3O2 Cathode

Galvanostatic intermittent titration technique (GITT) – a popular method for characterizing kinetic and transport properties of battery electrodes – is predicated on the proper evaluation of electrode active area. LiNi0.5044Co0.1986Mn0.2970O2 (NCM523) material exhibits a complex morphology in which sub-micron primary particles aggregate to form secondary particle agglomerates. This work proposes a new active area formulation for primary/secondary particle agglomerate materials to better mimic the morphology of NCM532 electrodes. This formulation is then coupled with macro-homogeneous models to simulate GITT and half-cell performance of NCM523 electrodes. Subsequently, the model results are compared against the experimental results to refine the area formulation. A single parameter, the surface roughness factor, is proposed to mimic the change in interfacial area, diffusivity and exchange current density simultaneously and detailed modeling results are presented to provide valuable insights into the efficacy of the formulation.

Outmatching superhydrophobicity: bio-inspired re-entrant curvature for mighty superamphiphobicity in air

Inspired by nature, a third factor of re-entrant surface curvature was introduced into the design and fabrication system of superamphiphobic surfaces in conjunction with the two other major factors of surface chemical composition and roughness.

Optimization of Machining Parameters for surface roughness on turning of Niobium alloy C-103 by using RSM

The focus of this research work is to study the effect of cutting parameters – speed, feed and depth of cut on the machinability of Niobium C-103 under dry machining condition using response surface methodology1 (RSM). Niobium based superalloys are an unusual class of metallic materials with an exceptional combination of high temperature strength, toughness, and resistance to degradation in corrosive or oxidizing environments2. In present study various machinability models were developed. This machinability models defined a functional relationship between cutting variables and responseof surface roughness. Cutting levels for experimentation was selected based on the cutting insert manufacturer recommendations. The Analysis shows that Feed is the most evident factor for Surface Roughness.

Influence Factors of Surface Roughness of Synthesized Diamond Films by Three-step Synthesis Method Using Flame Combustion

Influence Factors of Surface Roughness of Synthesized Diamond Films by Three-step Synthesis Method Using Flame Combustion

Removal of Cr (VI) from Industrial Waste Water by Iron Nanowires Synthesized via Porous Anodic Aluminum Oxide Template

Iron nanowires were successfully prepared by electrodeposition method via ordered nanoporous anodized aluminum oxide (AAO) template since the technique is simple and cost-effective. The preparation of nano porous anodized aluminum template involved annealing and electropolishing as a pretreatment. It has been found that regularity of pores increases after the pre-treatment. The average surface roughness factor (Ra) was measured with the help of portable surface roughness tester. Pore diameter, pore density, porosity and uniformity of pores was determined with the help of image-J software. Morphology of nanoporous oxide and iron nanowires was confirmed with FE-SEM and EDS analysis. The pore diameter of template ranged from 105 nm to 120 nm. The fabricated nano wires were found to have length of 643 nm and diameter of 103 nm with unique environmental applications.

Electrochemical impedance study of the kinetics of hydrogen evolution at a rough palladium electrode in acidic solution

Hydrogen evolution reaction (HER) was studied over a rough rotating disk palladium electrode in 0.1M sulfuric acid using steady-state polarization current measurements and electrochemical impedance spectroscopy (EIS). Among all the applied potentials, up to −0.074V, two semicircles were found on the complex plane plots, which were attributed to the HER. Surface roughness factor, Rf=23, was determined from the double-layer capacitance. The Tafel slope was −0.097Vdec−1 and the value of the intrinsic exchange current density was 0.22mAcm−2. The double layer capacitance, charge transfer resistance, adsorption resistance, and pseudocapacitance as functions of potential were also determined from the EIS results. The HER proceeds through the Volmer-Heyrovsky mechanism.

Implant surface roughness and patient factors on long-term peri-implant bone loss.

Dental implant placement is a common treatment procedure in current dental practice. High implant survival rates as well as limited peri-implant bone loss has been achieved over the past decades due to continuous modifications of implant design and surface topography. Since the turn of the millennium, implant surface modifications have focused on stronger and faster bone healing. This has not only yielded higher implant survival rates but also allowed modifications in surgical as well as prosthetic treatment protocols such as immediate implant placement and immediate loading. Stable crestal bone levels have been considered a key factor in implant success because it is paramount for long-term survival, aesthetics as well as peri-implant health. Especially during the past decade, clinicians and researchers have paid much attention to peri-implant health and more specifically to the incidence of bone loss. This could furthermore increase the risk for peri-implantitis, the latter often diagnosed as ongoing bone loss and pocket formation beyond the normal biological range in the presence of purulence or bleeding on probing. Information on the effect of surface topography on bone loss or peri-implantitis, a disease process that is to be evaluated in the long-term, is also scarce. Therefore, the current narrative review discusses whether long-term peri-implant bone loss beyond physiological bone adaptation is affected by the surface roughness of dental implants. Based on comparative studies, evaluating implants with comparable design but different surface roughness, it can be concluded that average peri-implant bone loss around the moderately rough and minimally rough surfaces is less than around rough surfaces. However, due to the multifactorial cause for bone loss the clinical impact of surface roughness alone on bone loss and peri-implantitis risk seems rather limited and of minimal clinical importance. Furthermore, there is growing evidence that certain patient factors, such as a history of periodontal disease and smoking, lead to more peri-implant bone loss.

Uncertainty quantification of infinite aligned wind farm performance using non‐intrusive polynomial chaos and a distributed roughness model

AbstractUncertainty of wind farm parameters can have a significant effect on wind farm power output. Knowledge of the uncertainty‐produced stochastic distribution of the entire wind farm power output and the corresponding uncertainty propagation mechanisms is very important for evaluating the uncertainty effects on the wind farm performance during wind farm planning stage and providing insights on improving the performance of the existing wind farms. In this work, the propagation of uncertainties from surface roughness and induction factor in infinite aligned wind farms modeled by a modified distributed roughness model is investigated using non‐intrusive polynomial chaos. Stochastic analysis of surface roughness indicates that 30% uncertainty can propagate such that there is up a 8% uncertainty in the power output of the wind farm by affecting the uncertainty in the position of the individual wind turbines in the vertical boundary layer profile and uncertainty in vertical momentum fluxes which replenish energy in the wake in large wind farms. Induction factor uncertainty of the wind turbines can also have a significant effect on power output. Not only does its uncertainty substantially affect the vertical boundary layer profile, but the uncertainty in turbine wake growth which affects how neighboring turbine wakes interact. We found that optimal power output in terms of reduction of uncertainty closely correlates with the Betz limit and is dependent on the mean induction factor. Copyright © 2016 John Wiley & Sons, Ltd.

Long-Term Effect of Surface Roughness and Patients' Factors on Crestal Bone Loss at Dental Implants. A Systematic Review and Meta-Analysis.

Publications from 2011 to 2015 were selected to evaluate effect of implant surface roughness on long-term bone loss as surrogate for peri-implantitis risk. 87 out of 2,566 papers reported the mean bone loss after at least 5 years of function. Estimation of the proportion of implants with bone loss above 1, 2, and 3 mm as well as analysis the effect of implant surface roughness, smoking, and history of periodontitis was performed. By means of the provided statistical information of bone loss (mean and standard deviation) the prevalence of implants with bone loss ranging from 1 to 3 mm was estimated. The bone loss was used as a surrogate parameter for "peri-implantitis" given the fact that "peri-implantitis" prevalence was not reported in most studies or when reported, the diagnostic criteria were unclear or of dubious quality. The outcome of this review suggests that peri-implant bone loss around minimally rough implant systems was statistically significant less in comparison to the moderately rough and rough implant systems. No statistically significant difference was observed between moderately rough and rough implant systems. The studies that compared implants with comparable design and different surface roughness, showed less average peri-implant bone loss around the less rough surfaces in the meta-analysis. However, due to the heterogeneity of the papers and the multifactorial cause for bone loss, the impact of surface roughness alone seems rather limited and of minimal clinical importance. Irrespective of surface topography or implant brand, the average weighted implant survival rate was 97.3% after 5 years or more of loading. If considering 3 mm bone loss after at least 5 years to represent the presence of "peri-implantitis," less than 5% of the implants were affected. The meta-analysis indicated that periodontal history and smoking habits yielded more bone loss.

Scale and size effects on fluid flow through self-affine rough fractures

A permeability estimation of a single rough fracture remains challenging and has attracted broad attention because of its fundamental importance. This study examines the effects of surface roughness on fracture flow and proposes a new, triple-effect permeability estimation model that takes surface and hydraulic tortuosity other than surface roughness factor (SRF) into account according to the functioning patterns. Due to the scale effect on hydraulic and surface tortuosities, it can also be reformulated into a scaling aperture-permeability equation for a self-affine fracture. Results indicate that tortuosity effects are scaled by 4(H-1) (H is the Hurst exponent) with the mean aperture and that the local SRF, as expected, is stationary at the measurement scale of the mean aperture. In addition, based on the scaling equation and the size effect of self-affine objects, flow regimes are examined and three flow regimes are then identified. Consequently, different permeability models for these regimes are established by fabricating fundamental and well-defined physical properties. The estimation results from these models are in excellent agreement with results from lattice Boltzmann simulations.

Sunlight driven photoelectrochemical light-to-electricity conversion of screen-printed surface nanostructured TiO2 decorated with plasmonic Au nanoparticles

In this paper, we report a promising sunlight-driven screen-printed TiO2 porous nanorods (PNR) photoanode decorated with Au plasmonic nanostructures for photoelectrochemical (PEC) light-to-electricity conversion. Fabricated photoanodes were characterized using field emission scanning electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, X-Ray diffraction analysis, X-ray photoelectron spectroscopy, N2 adsorption-desorption isotherms, UV–vis spectroscopy and electrochemical impedance spectroscopy in detail. The Au-PNR-TiO2 photoanode demonstrates superior PEC activities both under simulated sunlight and visible light irradiation. Interestingly, the Au-PNR-TiO2 shows high photocurrent density of 0.71mAcm−2 at +0.4V vs. Ag/AgCl, which is 65% higher than the pristine PNR-TiO2. It is shown that enhanced surface area, roughness factor, high crystallinity and one-dimensional framework which are offered by screen-printed porous TiO2 nanorods make a great microenvironment for more accessible reactive sites, light capturing ability, efficient charge generation and smooth transfer of photogenerated charge carriers. Decoration with Au nanoparticles is also shown that play an important role in improving the PEC performance by injecting hot electrons and excellent catalytic effect.

Mode I stress intensity factors of sickle-shaped surface cracks in round solid bars under bending moment

Sickle-shaped crack may occur on the surface of solid round cylinder under some specific reasons such as design discontinuities or material defects. This type of crack is capable to grow circumferentially around the bar and it is called a sickle-shaped surface cracks. The complete solution of stress intensity factors (SIF) of sickle-shaped surface cracks is hard to find and therefore the objective of this paper is to present the behaviour of these cracks under remotely applied bending moment. In order to understand the role of these cracks, there are seven crack aspect ratios, a/b considered, ranging from 0.0 to 1.2. For each crack aspect ratio, there are six relative crack depths, a/D used ranging from 0.1 to 0.6. ANSYS finite element program is used to model the crack. Stress intensity factor (SIF) which is based on the J-integral is used to characterize the cracks. For relatively shallow cracks (a/D  0.3), the role of SIFs along the crack front is insignificant regardless of a/b. However, for the deeper cracks (a/D > 0.3), the effect of a/b is tremendous on the SIFs. If a/b is increased from 0.0 to 1.2, higher SIFs are obtained around the central compared with the outer regions of the crack fronts. This is due to the fact that the circumferential cracks at both sides of the bar experience lack of mode I opening mechanism compared with the crack faces at the upper side cracks. It is suggested that the phenomena of crack closure are not only caused by the plastic deformation, surface roughness and other related factors but the shape of crack also plays an important role.

2D Hexagonal Boron Nitride (2D-hBN) Explored for the Electrochemical Sensing of Dopamine.

Crystalline 2D hexagonal boron nitride (2D-hBN) nanosheets are explored as a potential electrocatalyst toward the electroanalytical sensing of dopamine (DA). The 2D-hBN nanosheets are electrically wired via a drop-casting modification process onto a range of commercially available carbon supporting electrodes, including glassy carbon (GC), boron-doped diamond (BDD), and screen-printed graphitic electrodes (SPEs). 2D-hBN has not previously been explored toward the electrochemical detection/electrochemical sensing of DA. We critically evaluate the potential electrocatalytic performance of 2D-hBN modified electrodes, the effect of supporting carbon electrode platforms, and the effect of "mass coverage" (which is commonly neglected in the 2D material literature) toward the detection of DA. The response of 2D-hBN modified electrodes is found to be largely dependent upon the interaction between 2D-hBN and the underlying supporting electrode material. For example, in the case of SPEs, modification with 2D-hBN (324 ng) improves the electrochemical response, decreasing the electrochemical oxidation potential of DA by ∼90 mV compared to an unmodified SPE. Conversely, modification of a GC electrode with 2D-hBN (324 ng) resulted in an increased oxidation potential of DA by ∼80 mV when compared to the unmodified electrode. We explore the underlying mechanisms of the aforementioned examples and infer that electrode surface interactions and roughness factors are critical considerations. 2D-hBN is utilized toward the sensing of DA in the presence of the common interferents ascorbic acid (AA) and uric acid (UA). 2D-hBN is found to be an effective electrocatalyst in the simultaneous detection of DA and UA at both pH 5.0 and 7.4. The peak separations/resolution between DA and UA increases by ∼70 and 50 mV (at pH 5.0 and 7.4, respectively, when utilizing 108 ng of 2D-hBN) compared to unmodified SPEs, with a particularly favorable response evident in pH 5.0, giving rise to a significant increase in the peak current of DA. The limit of detection (3σ) is found to correspond to 0.65 μM for DA in the presence of UA. However, it is not possible to deconvolute the simultaneous detection of DA and AA. The observed electrocatalytic effect at 2D-hBN has not previously been reported in the literature when supported upon carbon or any other electrode. We provide valuable insights into the modifier-substrate interactions of this material, essential for those designing, fabricating, and consequently performing electrochemical experiments utilizing 2D-hBN and related 2D materials.

Enhancing electrocatalytic activity of bifunctional Ni3Se2 for overall water splitting through etching-induced surface nanostructuring

Abstract