Surface Roughness Of Specimens Research Articles

Comparison of platelet adhesion behavior on pure titanium surfaces modified by different techniques

To evaluate the platelet adhesion ability on pure titanium surfaces modified with different techniques. Pure titanium specimens were treated with 5 different surface modification techniques, including machine polish (MP), dual acid-etch (DAE), sand blast-large grit and acid-etch (SLA), micro-arc oxidation (MAO) and anodized titania nanotube (TNT). The surface topographies of specimens were observed by scanning electron microscopy (SEM). Chemical compositions, surface roughness and static water contact angle of specimens were detected by energy dispersive spectrometer (EDS), laser scanning confocal microscope (LSCM) and contact angle analyzer respectively. Platelets were cultured on specimen surfaces for 30 min. The amount and viability of adhered platelets adhered were evaluated. Platelet distribution and morphology were observed by LSCM and SEM. Surface topographies of the five groups of specimens differed significantly. MP, DAE, SLA and MAO surfaces showed micro-scale topographies, while TNT surfaces showed nano-scale topography with nanotubes at the diameter of (80.46 ± 0.35) nm. The surface roughness of MAO was the highest among the 5 groups. TNT surfaces demonstrated the lowest roughness as well as the lowest static water contact angle as 13.55° ± 0.96°. The amount of platelets adhered on TNT surface was the greatest as (300 729 ± 8 325) platelet/µl and the viability was the highest (A450 value 2.14 ± 0.05). Platelet adhered intensively on TNT surfaces, forming pseudopodia, extending and connecting with each other. Surface properties of pure titanium affect platelet adhesion ability. Nano-scale topography can greatly improve platelet adhesion. Increased surface roughness and hydrophilicity can improve platelet adhesion ability.

Analysis on the effects of rotational speed of grinding stone on removal behavior of rail material

The grinding process for maintaining the railroad rails can affect their performance. A rail grinding friction testing apparatus was developed to investigate the effects of rotational speed of grinding stone on removal behavior of rail material. The rail-grinding stone contact consists of a round, flat grinding stone and two test specimens made from Mn–steel rails that are pressed against the face of the stone. The effects of grinding wheel rotational speed on the abrasive removal mechanism of rail material are explored in detail. The results indicate that as the grinding wheel rotational speed increases, the friction coefficient, the surface roughness of rail specimens and the width of the wear grooves decrease. The grinding wear volume, the microindentation hardness of the rail specimens and the surface temperature-rise all increase as the number of grinding cycles increase. Wear debris collected during the test is composed of round particles and curled cutting chips. The debris is mainly composed of Fe3O4, FeO and Fe. As grinding rotational speed increases, the content of Fe3O4 and FeO increases but the width of the cutting chips decreases.

Simulation and measurement of surface roughness via grey scale image of tool in finish turning

Study on the surface roughness of specimen is a significant field of research because this parameter affects the performance of the machined parts. Meanwhile, the evaluation of surface roughness of specimens using a vision system via the images captured from the specimen is an interesting method which is widely used. Although the effect of flank and crater wear has been investigated extensively in the past researches on surface profiles, some reports indicated that, in finish turning, the nose radius wear has a greater effect on the surface profile of specimen. Although, vibration can affect the surface profile of a specimen in rough turning, the final surface profile in the product used is usually shaped by finish turning that may not be affected by vibration using the robust machine tool. In this work, a machine vision was used to capture the images of the tool tip in-cycle. The 2-D images of the nose area of tool tips were used to simulate the surface profile of specimens in finish turning. The simulated images of specimens in a range of machining condition were detected using the algorithm of this work. The results showed that this method can be used successfully to simulate and evaluate the surface profile of a specimen in finish lathe machining as a fingerprint of the tool tip. This method can be used for forecasting the final surface profile in order to control the performance of products.

Wear Testing of Principal Friction Pairs in Axial Piston Pump Based on Taguchi Design Method

While axial piston pump is the core component of hydraulic system, its service life and reliability depend much on the selection of materials, friction pairs and process parameters. To identify these factors, wear condition of friction pair is conducted by using MWF-10 wear rig. Based on ANOVA of Taguchi Method,the influences of surface roughness and hardness on wear loss and friction coefficient are compared. In addition, the results show that the optimal friction pair and surface roughness of hard specimens have influence mostly on the wear loss and the friction coefficient.

MECHANICAL PROPERTIES AND RELIABILITY OF GLASS-ALUMINIUM COMPOSITE AS INSERT MOLD

Plastic injection mold made of tool steel is generally utilized for large lots production. Running for small lots of product is a new trend of demand, so that the mold would be relatively expensive and not competitive. The aim of the present work is to find an alternative material and process for low cost injection mold that suitable for small lots. For these reasons, aluminum-glassacrylic particulate composite would be proposed as a material for manufacturing of low cost plastic injection mold. In this work, an insert mold as part of the injection molding was selected for the case study. Composite was examined to know its characteristics. The part with size of (80mm x 10mm x 10mm) and (30mm x30mm x30mm) made of particulate composite material was selected as specimen. Material of the specimen was aluminum powders (<297 μm), glass powders (<74 μm) and acrylic powders (<74 μm); the volume ratio is 1:1:1. Acrylic was used for binder when composite made by layer manufacturing method, using Selective Heater Melting (SHM) machine. The specimen was prepared into three steps: manufacturing of composite (green specimen) by SHM machine, heating green specimen to burn up the acrylic, and resin impregnation. There were 3 types of specimens: green specimen before heating at 700°C, green specimen after heating at 700°C, and green specimen after heating at 700°C that continued by resin impregnation. Tests was performed to investigate its bending strength, surface hardness, surface roughness, and dimensional error. The other composite (specimen) was insert mold, made by layer manufacturing method, using SHM machine. Case study was carried out by testing an insert mold to know the reliability of insert mold. Bending strengths of green specimen, before and after heating at 700°C, were 2.07 and 8.23 MPa, respectively; and after resin impregnation was 17.15 MPa. Dimensional errors in the direction of X, Y, and Z-axis for green specimen of (30mm x 30mm x30mm) before heating at 700°C were 8.65, 2.7, and 3.8 mm, respectively; and after heating at 700°C were 7.90, 1.10 and 0.90 mm, respectively. Surface roughness of green specimen before and after heating at 700°C were 46.12 and 33.48 μm, respectively; and after resin impregnation was 12.17 μm. Surface hardness of specimen after resin impregnation was 14.199 BHN. The amount of plastic parts that could be produced by insert mold was 120 and 126 pieces. Although mechanical strength of this composite was lower than that of tool steel that used for common plastic injection mold, but this composite material was less expensive and suitable for small lots production.

Adverse effects on PMMA caused by mechanical and combined methods of denture cleansing.

This study evaluated the abrasiveness of mechanical and combined methods of denture hygiene, by the analysis of mass loss and surface roughness. Acrylic resin specimens (Plexiglass) were brushed by a tooth brushing machine (Mavtec) with a soft brush (Tek) and water (control) or four dentifrices (Sorriso, Colgate, Polident and Corega) (Experimental groups) for 50 min, representing one year of brushing (mechanical method). After brushing, the specimens were immersed in 0.5% sodium hypochlorite simulating a daily cleaning of 20 min for one year (combined method). Distilled water (23 ºC) was employed as control. The mass loss (g) was analyzed by an analytical balance and the surface roughness (μm) by a rugosimeter. Data were subjected to ANOVA and Bonferroni test (α=0.05). Polident dentifrice showed lowest values of mass loss for both methods (mechanical: -0.0072±0.0017, combined:-0.011±0.002) and the combined method resulted in greater mass loss than the mechanical, except for Corega. For the surface roughness, after the mechanical method, the lowest values were registered for water (-0.007±0.016) and Polident (0.402±0.378); for the combined method, water (-0.063±0.013) showed the lowest values; there was no statistically significant difference between methods. It was concluded that Polident was the less abrasive dentifrice and the association between chemical and mechanical methods increased the mass loss but did not change the surface roughness of specimens.

Effects of a ball-burnishing process assisted by vibrations in G10380 steel specimens

This paper explores the effects on the surface roughness, hardness and residual stress of G10380 steel specimens milled and treated with a ball-burnishing process assisted by vibrations. These vibrations are incorporated through the attachment of an induced coil module to a conventional burnishing tool, with forces transmitted through a pre-loaded spring. A positive effect of vibrations on the improvement and efficiency of the burnishing treatment is demonstrated, empirically proving that the vibrations introduce additional energy into the system that aids with displacements along the surface of the material to reallocate the crystalline structure. Significant results are found in terms of final surface roughness, which is highly improved in comparison to conventional burnishing treatments, even with fewer passes and a significant time reduction. Less robust results are observed in terms of specimen hardness and residual stress, but future improvements could be derived with a thorough development of the vibration system.

Effect of denture cleansers on color stability and surface roughness of denture base acrylic resin.

Color stability of acrylic resin is one of the most important feature for denture wearers. Many patients use detergent solutions to remove denture stains. The purpose of this study was to evaluate color stability and surface roughness of two common acrylic resins in different detergent and tea solutions. 112 acrylic resin blocks of Meliodent and Acropars (each 56 blocks) were divided into seven groups of different treatment: 1% sodium hypochlorite for 10 min a day for 1 month (H10m), 1% sodium hypochlorite for 8 hours a day for 1 week (H&h), Correga tabs solution for 8 hours a day for 1 month (C&H), tea bag for 2 hours a day for 1 month (T2 h), tea bag for 2 hours a day then 10 min in 1% sodium hypochlorite for 1 month (T-H), tea bag for 2 hours then 8 hours in the Correga tab solution a day for 1 month (T-C), and finally distilled water for 1 month as a control group (con). After specimen's treatment, color (CIE Lab) and surface roughness (Ra, µm) of samples were measured. The results were analyzed by analysis of variance (ANOVA), followed by Tukey's HSD and Dunnett T3. Group T2h exhibited a significant (P<;0.05) color change and control specimens exhibited the lowest color change. Sodium hypochlorite caused a significant (P<0.05) color change in the Acropars group in comparison with the Meliodent group. In the Correga tab solution the difference was not significant (P=0.155). There was a significant (P<0.05) color change in the T-H treatment. The Acropars and Meliodent acrylic resin did not a show significant difference in surface roughness after different treatments. Sodium hypochlorite 1% for 10 minutes a day in a month is the recommended hygiene protocol. The color stability of acryl is brand-type dependent but surface roughness is not.

テラヘルツ波を用いた誘電体の表面粗さ測定

The surface roughness of sandpaper specimens with alumina abrasive was measured based on the effective reflectivity of terahertz waves. Measurement results based on the frequency dependence of the effective reflectivity were in agreement with measurement results using a contact surface roughness gauge to within 10% for surface roughness 10-35 µm. In addition, the frequency-averaged effective reflectivity was calculated with the surface roughness as a parameter. This provided a calibration curve to convert the measured frequency-averaged effective reflectivity to surface roughness. Measurement results based on the frequency-averaged effective reflectivity were in agreement with measurement results using a contact surface roughness gauge for surface roughness below 25 µm. The effect of the paint layer coating the abrasive did not result in significant error. The results showed that terahertz waves can be used for noncontact measurement of the surface roughness of dielectric surfaces.

Abrasive water jet machining and mechanical behavior of banyan tree saw dust powder loaded polypropylene green composites

Banyan tree saw dust powder (BSD) filled Polypropylene (PP) green composites have been fabricated with varying amounts viz., 0%, 20%, and 40% of BSD particulate filler by using a co‐rotating twin screw extruder followed by injection molding. The mechanical properties such as surface hardness, tensile behavior, and impact strength of the fabricated PP/BSD green composites have been studied in order to standardize the composites. Abrasive water jet (AWJ) machining has been reported mainly for ceramics, concrete, and glass but not much literature is available on AWJ machining of polymer composites. This research is aimed at examining the AWJ machining of green polymer composites. The effect of BSD loading on the AWJ machining behavior of the PP/BSD green composites has been investigated. Furthermore, the effect of addition of 4% maleic anhydride grafted PP (coupling agent) and 4% talc (mineral filler) on the machining behavior of PP/BSD composites has also been evaluated. Surface roughness and optical micrographs of the AWJ cut composite specimens were examined to assess the effect of BSD content, AWJ traverse speed and pressure on the machining behavior of the composites. In order to probe the mechanism of AWJ machining behavior of PP/BSD composites, the kerf width and taper have been measured and results are correlated. POLYM. COMPOS., 37:1754–1764, 2016. © 2014 Society of Plastics Engineers

Effect of zirconia surface treatments on the shear bond strength of veneering ceramic

Background: The aim of the study was to investigate the effect of surface treatments of zirconia (grinding and sandblast with 50μm, 100 μm) on shear bond strength between zirconia core and veneering ceramic. Material and methods: Twenty-eight presintered Y-TZP ceramic specimens (IPS e.max ZirCAD, Ivoclar vivadent) were fabricated and sintered according to manufacturer’s instructions. The core specimens were divided randomly in to 4 groups, group 1: no surface treatment, group2: zirconia specimens were ground with silicon carbide paper up to1200 grit under water cooling, group3: zirconia specimens were ground and sandblast with 100 μm alumina, group 4: zirconia specimens were ground and sandblast with 50 μm alumina. Surface roughness of specimens were analyzed by surface profilometer, then veneering ceramic (IPS e.max ceramic, Ivoclar vivadent) was applied on the specimens& fired according to manufacturer’s instructions. All specimens were subjected to shear force in a universal testing machine at a crosshead speed of 1mm/min. The shear bond strength values were analyzed with one-way ANOVA; the fractured surfaces were examined with a stereo-microscope to observe the failure mode. Results: The mean of shear bond strength values in MPa were 24.75 for group 4, (17.72) for group 3, (17.68) for group2, (14.61) for group 1.The airborne-particle abrasion with 50μm group showed significantly higher bond strength than other groups. The airborne-particle-abraded with 100 μm group was not significantly different from grinding group. Conclusion: With limit of this study, the sandblast with 50 μm alumina was enhance the SBS between zirconia &veneering ceramic, and zirconia-veneering ceramic bonding is not only influenced by surface roughness. But also may be other factors.

Interface Friction between Glass Fibre Reinforced Polymer and Gravel Soil

In soil-structure interaction problems, the frictional resistance between soil and structure is very important to have an appropriate system analysis. It includes retaining walls, deep foundations, soil samplers, soil and geo-membrane interface strength, and the stability of mechanically stabilized structures. Fibre Reinforced Polymer (FRP) is a synthetic material and can be effectively used for strengthening of soils and substructures, and hence it is important to study the interface friction between these FRP sheets with soil. This study will provide some insight knowledge regarding the interfacial friction between gravel soil with glass fibre reinforced polymer. It will be beneficial to the researchers and practicing engineers working in soil-structure interaction problems. The parameters varied in this investigation are surface roughness, orientation of fibre and normal stress (0.05 N/mm2 to 0.20 N/mm2). Experimental results show that surface roughness of specimens and fibre orientation was significantly changes the interface friction angle. Shear strength at the interface increases with increase in normal stress and surface roughness. Key words: Direct shear test, gravel soil, internal friction angle, interface friction angle, GFRP.

ESTIMATING THE SHEAR MODULUS OF SOILS BASED ON SURFACE ROUGHNESS

The purpose of this paper is to estimate the initial shear modulus of soils based on the surface roughness of materials. Interface shear modulus depends on soil type & gradation and surface roughness of specimens. By considering all the factors, a simple mathematical equation was given by Murugan et al. (2014) for the interface shear modulus between soil and structural material. Interface shear modulus of soil was evaluated by using the mathematical equation given by Murugan et al. (2014).Result indicates that interface shear modulus increases with the increment of the surface roughness of the specimens used in this study. The highest peak shear modulus is achieved when the surface is rough. This study is very important in the field of earthquake geotechnical engineering.

The Effect of Lubricants and Material Properties in Surface Roughness and Formability for Single Point Incremental Forming Process

The single point incremental forming (SPIF) is a manufacturing process which allows small batch and asymmetric shape fabrication. The research focuses on its applications by consider surface roughness and formability. The surface roughness of specimen was resulted by the influence obtained between tool and specimen, where the lubricant played a significant role during the forming process, as well as material elongation as a mechanical property governed the formability of metal sheet. Surface roughness tester, SEM, EDS and profilometer were used for the characterizations. The results showed that low roughness value (Ra) of SUS 304 and SUS 316L obtained by applying air blowing as a lubricant, while Ti Gr2 could obtain low roughness by using MoS2. The behavior of wear was an adhesive wear which transfer to an abrasive wear. SUS 304 and SUS 316L sheet of test specimens achieved higher depth in forming by air lubricant and MoS2, and Ti Gr2 sheet revealed a better formability with MoS2. Furthermore, the highest depth was correlated with high roughness value for each material.

Investigation of the effects of graphite flake alignment on thermal emissivity by applying a magnetic field during coating of an aluminum sheet

In this study we investigated the effects of graphite flake alignment on thermal emissivity by applying a magnetic field during coating of aluminum sheets with graphite. The coating paste was prepared by ball milling graphite flakes with an organic binder. The graphite flake content was 9.1, 13.0, 16.7, 20.0, or 23.1 wt.%. After coating of aluminum sheets with the paste by dipping, a magnetic field was applied vertically to the coated aluminum sheet by use of neodymium magnets. It was observed that the graphite flakes were aligned at an angle to the surface by application of the magnetic field. In contrast, in the absence of the magnetic field the graphite flakes were aligned horizontally on the aluminum sheets. The surface roughness of specimens prepared by use of a magnetic field (MF; R a = 10.172–14.654 μm) was more than twofold that of specimens for which no magnetic field was applied (NMF; R a = 4.564 μm). The thermal emissivity of MF9 (9.1 wt.% graphite; e = 0.80) was higher than that of NMF9 (9.1 wt.% graphite; e = 0.77). The thermal emissivity of MF20 (20.0 wt.% graphite) was 0.91, the highest in this study. It was shown that flakes aligned at an angle to the surface contribute to enhanced thermal emissivity. Well aligned graphite flakes are therefore expected to enable high thermal dissipation from electronic components.

Effect of Deoxidation Pretreatment on the Corrosion Inhibition Provided by a Trivalent Chromium Process (TCP) Conversion Coating on AA2024-T3

Aluminum alloy surfaces are typically (i) degreased and (ii) deoxidized and or desmutted to expose a clean and low-oxygen surface in preparation for the application of a pretreatment conversion coating. We hypothesized that the corrosion inhibition provided by one type of conversion coating, trivalent chromium process (TCP), would depend on the deoxidation chemistry and treatment time due to effects on the specimen's surface cleanliness and surface roughness, pit density, and pit depth. To this end, the effect of treatment time in an acidic fluoride deoxidizer/desmutter on the corrosion inhibition provided by a TCP coating on AA2024-T3 was studied. Longer treatment times of 6 and 12 min produced greater surface roughness, pit density and pit depth than did shorter times of 0.5 and 2 min. As a consequence, the TCP coating formed less completely and with more defects over the former surfaces. Greater corrosion inhibition was found on the less damaged specimens as evidenced by decreased anodic and cathodic currents in polarization curves, increased polarization resistances, Rp, and more positive breakdown or pitting potentials, Epit, in a choride-containing electrolyte solution. Deoxidation in 0.1 M NaOH was also investigated because of the more uniform aluminum dissolution that occurs in this medium. These specimen surfaces remained relatively smooth with the TCP coating providing the greatest level of corrosion inhibition, as evidenced by a larger Rp and more positive Epit. This is attributed to reduced surface roughing and pitting as well as the formation of an inert oxide on the exposed copper intermetallics.

Evaluation of Surface Profile Parameters of a Machined Surface Using Confocal Displacement Sensor

This paper describes the use of non-contact type chromatic confocal displacement sensor for estimation of surface profile parameters such as Ra, Rq and Rt of different machined surfaces. The confocal displacement sensor can measure surface roughness of the order of 5nm on conducting and non-conducting material. The surface irregularities of the profile measured over the evaluation length is related to the response of chromatic confocal displacement data. Confocal sensor response is analyzed to determine the displacement variations from the profile data points of the surface. Based on the confocal chromatic image principle, a new technique is used to measure the micro level surface finish. The new method is validated by measuring surface roughness of kwon specimen in the range of 1.6 - 3.2μm using an experimental setup developed and by stylus method. The estimated profile parameter values are in good agreement with the values obtained by stylus method and hence the confocal displacement based method can be implemented to measure surface roughness parameters.

Some Physical characteristics of thermally modified oriental- beech wood

Heat treatment of Oriental-beech (Fagus orientalis) wood was carried out by hot air in an oven for 2, 4, and 8 h at 140, 170, and 200°C. After heat treatment, some physical characteristics such as surface roughness, color, glossiness, and mass loss of Oriental-beech wood specimens were measured. Our results showed that heat treatment caused decrease in surface roughness, glossiness, and mass loss values of Oriental-beech (Fagus orientalis) wood specimens. The decrease in lightness at all temperatures indicates that the specimens become darker with the treatment time. While, a* coordinate (red component) decreased as temperature increased, b* coordinate (yellow component) initially increased at 140°C and then decreased at 170°C and 200°C.

Damage Effects of Charged Particles Irradiation on An Epoxy Resin

In this study, the mass loss effect and the related outgassing of 5224 epoxy resin have been investigated. Subsequent irradiation of 160 keV proton and electron with the fluences ranging from 5.4×1015 to 3.75×1016 cm−2 in vacuum (1.2×10−5 Pa) was performed. The increase of the fluence of proton or electron made the mass loss ratios increase, then level off. The surface roughness of specimens increased followed by augmenting as the function of fluence. The outgassing rate of most molecule ions reached to maximum under the fluences ranging from 5.4×1015 cm−2 to 1.18×1016 cm−2. With further increasing fluence, the outgassing rate decreased owing to the effects of carbon enrichment or even carbonification developed gradually on the surface layer of the irradiated specimens. It is suggested that two events might play vital roles in dominating the magnitude of the outgassing rates: one is the formation of molecule ions; the other is the enrichment of carbon on the surface layer.

Effects of a carbon nanotube-collagen coating on a titanium surface on osteoblast growth

This study was performed to evaluate the effect of collagen-multi-walled carbon nanotubes (MWCNTs) composite coating deposited on titanium on osteoblast growth. Titanium samples coated with only collagen and MWCNTs were used as controls. Pure titanium was coated with collagen-MWCNTs composite coating with 5, 10 and 20μgcm−2 MWCNTs by dip coating method. Scanning probe microscopy, field emission scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy were used to ascertain the root mean squared roughness, structural and morphological features and, the interaction between the collagen and the MWCNTs, respectively. The biocompatibility of the collagen-MWCNTs composite coated Ti was assessed by MTT and ALP activity assays after culturing the cells for 2 and 5 days. The study reveals that root mean squared surface roughness of collagen-MWCNTs composite coated titanium is relatively higher than those of collagen and MWCNTs coated Ti. There is a strong interaction between the MWCNTs and the collagen, which is supported by the inferences made in FE-SEM and TEM studies and further confirmed by FT-IR spectra. Among all the specimens tested, cell proliferation is relatively higher on collagen-MWCNTs composite coated Ti specimen incorporated with 20μgcm−2 of MWCNTs (p<0.05) after 5 days of cell culture. Cell proliferation studies confirm the existence of a strong dependence of the extent of cell proliferation on the amount of MWCNTs incorporated in the composite; the higher the amount of MWCNTs, the greater the extent of cell proliferation. The higher surface roughness of collagen-MWCNTs composite coated Ti specimens is considered responsible for the relatively higher extent of cell proliferation. The MWCNTs incorporated in the composite could have also contributed to the cell viability and growth.