Average Surface Roughness Values Research Articles

Enhancement of bone mineral formation on Ti6Al4V surface by PM-EDCLT combined with acid etching

For Bone-anchored limb prostheses, osseointegration plays a significant role in the mechanically stable interface between bone and implants. Titanium alloy is the most usable alloy for hard tissue replacement. The drawbacks of the titanium implant are corrosion, leaching and poor osseointegration. In this research, powder mixed (hydroxyapatite) - electric discharge-assisted centreless turning (PM-EDCLT) (Impulse current- 5amp, duty factor- 57%, hydroxyapatite concentration 18 g/l, and rpm-360) and acid etching (solution – HF: HNO3: H2O = 1:2:50) were used for the surface modification of screw-fit implants. Average surface roughness value maximum in PM-EDCLT machined surface (1.249 µm) followed by PM-EDCLT machined + 5 min. Acid etching (1.055 µm), PM-EDCLT machined + 10 min. Acid etching (0.9829 µm), PM-EDCLT machined + 15 min. acid etching (0.8223 µm), bare surface with 10 min. Acid etching (0.2866 µm), 15 min. acid etching (0.2714 µm) and 5 min. Acid etching (0.1896 µm). Investigations using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR) proved that the deposited layer on the powder-mixed EDCLT machined sample was hydroxyapatite. After sinking samples in the Simulated Body Fluid (SBF) solution, it was concluded that the percentage of bone minerals like oxide, Ca, and P deposition increases after increasing the acid etching time on the PM-EDCLT machined surfaces. Little effect was found on the deposition of bone minerals on the surface of acid etching only by increasing the etching time. There is a clear trend of decreasing the contact angle with increasing the acid etching time on the PM-EDCLT surfaces.

Effect of Minimum Quantity of Lubricant on Carbide Tools and Surface Integrity in the Machining of Titanium Aluminides

Titanium aluminides are being explored as potential materials for the aeronautical sector. However, their application is limited by the high costs of processing and their difficulties in machining. This research evaluates the effectiveness of the minimum quantity lubrication technique (MQL) on the turning process of Ti48Al2Cr2Nb aluminide in terms of tool wear, tool life, cutting forces, surface integrity, and temperature. It was found that MQL conditions can improve the process efficiency, reducing the thermally induced wear mechanisms and enlarging the tool life compared to dry machining. Furthermore, it allows the cutting speed to be incremented, leading to lower processing times. However, MQL seems to not be effective in the reduction of the strain-hardening effect near the machined surface and, although the number of microcracks is reduced, defect-free surfaces cannot be obtained. Moreover, similar microstructural alterations as for dry cutting were detected. The best cutting conditions in terms of surface quality were assessed using the central composite face (CCF) design and surface response methodology. Optimization of the surface roughness under industrially viable cutting conditions was achieved with an average surface roughness value, Ra, of 0.29 µm (feed rate of 0.05 mm/rev, a cutting speed of 54.6 m/min and a depth of cut of 0.125 mm).

Novel short Agave americana based biocomposite and nanobiocomposites for automotive applications

Short fibers of Agave Americana (AA) was extracted from its plant leaf, was chemically treated with Ac2O, HCOOH, H2O2, KMnO4 and NaOH, and then characterized by Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), thermo-gravimetric/differential thermo-gravimetric (TGA/DTG), and field emission-scanning electron microscopy (FE-SEM). PVA stabilized copper nanoparticles from chemical reduction method was characterized using field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDAX), powder X-ray diffraction (PXRD), Dynamic light scattering analysis (DLS), UV–visible absorption spectroscopy, Fourier Transform infrared (FT-IR) spectroscopy and Thermogravimetric analysis/differential thermogravimetry (TGA/DTG). Bio-composites (AA + Polyester Resin (PE) and hybrid nano bio-composites (AA + Polyester Resin (PE) + Cu) were prepared from the untreated and treated AA fibers and further characterized. The synergistic effect of chemical treatment on morphological (SEM), thermal (TGA/DTG), mechanical properties (flexural, tensile, impact and compressive strength) followed by % water absorption were examined. The average surface roughness values (Ra) of chemical treated fiber was identified to be in decreasing manner along with compression strength of biocomposite in the order of untreated (10.74 μm, 44.01 MPa) > NaOH (8.55 μm, 45.07 MPa) > HCOOH (3.49 μm, 24.10 MPa) Ac2O (3.24 μm, 22.10 MPa) > H2O2 (2.51um, 17.9 MPa) > KMnO4 (1.52 μm, 15.1 MPa) treated fibers. Subsequently, the addition of 2s@PVA led to reverse the order namely, the compressive strength of the bionanocomposites were Untreated (10.74 μm, 9.0 MPa) < NaOH (8.55 μm, 0.1 MPa) < HCOOH (3.49 μm, 3.6 MPa) < Ac2O (3.24 μm, 7.6 MPa) < H2O2 (2.51um, 13.3 MPa) < KMnO4 (1.52 μm, 44.1 MPa) treated fibers. Similarly, the biocomposite where the fibres were treated with NaOH, HCOOH were more rough and had, good interconnection between fiber/PE matrix along with enhanced mechanical properties. On addition of nanobiocomposite, only KMnO4 treated fiber composite possed significant mechanical properties. Therefore, mixing CuNPs@PVA with KMnO4 treated fibers led to significant boost to the mechanical properties and minimised the % water absorption properties when compared to the untreated AA/PE biocomposites. The KMnO4 treatment of the AA fiber and addition of copper nanoparticles caused the enhancement of thermal properties, tensile strength and flexural strength. But, these nanobiocomposites were observed to have low impact strength; while, H2O2 treated nanobiocomposites had highest impact strength. The chemical treatment of the AA fiber with NaOH, Ac2O and KMnO4 developed the water resistance of the respective biocomposites. All the nanobiocomposites with chemically treated AA fibers (except Ac2O) were found to have high water resistance. So, they can be used in automotive industry for non-structural applications.

Effect of tabebuia heterophylla plant leaves extract on corrosion protection of low carbon steel in 1M HCl medium: Electrochemical, quantum chemical and surface characterization studies.

In the current study the chemical constituents of Tabebuia heterophylla plant leaves extract (THLE) evaluated as corrosion inhibitor for low carbon steel (LCS) in 1 M HCl. The major component present in plant extract was Hexadecanoic acid 2-hydroxy-1-(hydroxymethyl) ethyl ester confirmed by Gas Chromatography with Mass spectroscopic (GC-MS) analysis. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation (PDP) and weight loss measurements were used to evaluate the THLE ability to protect low-carbon steel surface against corrosion in 1M HCl medium. The maximum inhibition efficiency reported as 95.45%, 93.99% and 94.79% by weight loss measurements, EIS and PDP methods respectively. In the prolongation of the work, the entropy of adsorption (Δ Sa*), enthalpy of adsorption (Δ Ha*), Gibbs free energy of adsorption (Δ Ga*), and activation energy (Ea) of the reaction were calculated. In absence of inhibitor, the Ea value was found to be minimum 49.38 kJ/mol whereas for optimum concentration of THLE it was found to be 77.2 kJ/mol implies more energy is required to undergo corrosion. The surface morphological observation from Scanning Electron Microscope (SEM), Atomic Force Microscopic (AFM) and Contact angle explored the effective adsorption of THLE. AFM values revealed that average surface roughness (Ra) value of LCS is high (188.08), where as in the presence of THLE, Ra values significantly reduced to minimum value of 37.226. Further chemical interactions between THLE and the low-carbon steel surface as well as inhibitory mechanism were further elucidated by theoretical simulations such as Density Functional Theory (DFT) calculations and Molecular dynamics (MD) simulations.

The effect of tobacco leave pastes (Nicotiana tabacum L.) 50% concentration as a denture cleanser on the surface roughness of thermoplastic nylon

Microporosity of thermoplastic nylon can lead to increased surface roughness values. Surface roughness of thermoplastic nylon can facilitate colonization of microorganisms that can lead to denture stomatitis. The mechanical cleaning process of denture using an electric toothbrush and denture cleaning paste is considered effective for removing plaque and microorganisms attached. To reduce surface roughness, the use of natural materials such as tobacco leaves is considered beneficial because it can reduce the content of abrasive materials. This study aims to determine the effect of tobacco leaf paste as a denture cleanser on the surface roughness of thermoplastic nylon. This study using a laboratory experimental design with a post test only control group design involving 27 samples sized 60 x 10 x 2.5 mm which were divided into three groups including the brushing control group without paste, the brushing group with placebo paste, and the brushing group with 50% tobacco leaf paste (TLP). The results showed that tobacco leaf paste was considered effective as a thermoplastic nylon denture cleanser and had an effect on reducing surface roughness values with an average surface roughness value that was still acceptable to the oral cavity. In conclusion, 50% tobacco leaf paste is recommended as an effective denture cleanser and produces surface roughness values acceptable to the oral cavity.

Pengaruh Kedalaman Pemakanan dan Kecepatan Potong pada Pembubutan Finishing Material Baja SKD 11 terhadap Kekasaran Permukaan Benda Bubutan

One important factor in achieving good quality value for a product in the machining process is to look at the level of roughness produced in the machining process. This research aims to determine the effect of feed depth and cutting speed on surface roughness. The process variables used in this research are feeding depth (mm) and cutting speed (m/min). Each variable has 3 levels, namely feeding depth of 0.5, 0.6 and 0.7 mm. Cutting speed 65, 70 and 75 m/min. In this research method, researchers used the full factorial method. The material used in this research is SKD 11 steel. The conclusion obtained from the research is that the minimum surface roughness is at a cutting depth of 0.6 mm with a cutting speed of 65 m/minute, with the average surface roughness value obtained being 0.883 (µm ). The maximum surface roughness is at a feed depth of 0.6 mm with a cutting speed of 70 m/minute with an average surface roughness value of 1.254 (µm).

Active Compliance Smart Control Strategy of Hybrid Mechanism for Bonnet Polishing.

Compliance control strategies have been utilised for the ultraprecision polishing process for many years. Most researchers execute active compliance control strategies by employing impedance control law on a robot development platform. However, these methods are limited by the load capacity, positioning accuracy, and repeatability of polishing mechanisms. Moreover, a sophisticated actuator mounted at the end of the end-effector of robots is difficult to maintain in the polishing scenario. In contrast, a hybrid mechanism for polishing that possesses the advantages of serial and parallel mechanisms can mitigate the above problems, especially when an active compliance control strategy is employed. In this research, a high-frequency-impedance robust force control strategy is proposed. It outputs a position adjustment value directly according to a contact pressure adjustment value. An open architecture control system with customised software is developed to respond to external interrupts during the polishing procedure, implementing the active compliance control strategy on a hybrid mechanism. Through this method, the hybrid mechanism can adapt to the external environment with a given contact pressure automatically instead of relying on estimating the environment stiffness. Experimental results show that the proposed strategy adapts the unknown freeform surface without overshooting and improves the surface quality. The average surface roughness value decreases from 0.057 um to 0.027 um.

Effect of different polishing methods applied to denture base materials on microbial adhesion and surface roughness

Aim: The aim of our study was to investigate the effect of various polishing processes applied to different types of PMMA (polymethyl methacrylate) denture base materials on the surface roughness and microbial adhesion of the base material. Methods: Sixty specimens each were prepared from heat-polymerized conventional PMMA (G), heat-polymerized injectable PMMA (E), and prepolymerized CAD/CAM PMMA (C) denture base materials. All sample surfaces were sanded with 800, 1000, 1200, and 2500 grit silicone carbide abrasives. The specimens of each denture base material were divided into three subgroups (n=20) in which different polishing methods were applied. The first group was mechanically polished (M), and the other two groups were chemically polished with light polymerized glaze liquids [Palaseal (Ps), Optiglaze Color (Og)]. A profilometer device was used to evaluate the surface roughness. Colony counting was performed to evaluate bacterial colonization after one day. The data obtained from all these measurements were evaluated using an analysis of variance, and Bonferroni corrected test was used for multiple comparisons of means (p=0.05). The interaction between surface roughness and bacterial colonization was examined by the Pearson correlation test. Regression analysis was performed to determine the relationship between them. Results: When PMMA base materials were compared, the lowest average surface roughness (Ra) values and bacterial colonization values were obtained in Group C. When polishing methods were compared, the lowest average surface roughness values were obtained in Group M. As a result of bacterial colonization measurement, lower colonization values were obtained with standardized mechanical polishing compared to other groups. Conclusion: There was no difference between the different PMMA base materials in terms of surface roughness, but there were statistical differences in bacterial colonization. The results of our study showed that mechanical polishing gave better results than light-activated glazing agents. How to cite this article: Yarar S, Değer Y, Tekin S. Effect of different polishing methods applied to denture base materials on microbial adhesion and surface roughness. J Med Dent Invest 2023; 4: e230351. https://doi.org/10.5577/jomdi.e230351

Morphology, phase composition, surface roughness evolution and growth mechanism of hot-dip aluminum coating on Mo substrate

The Al-rich hot-dip aluminum composite coatings were synthesized on Mo surface by hot-dip aluminizing under different deposition processes. The aluminide coatings present a very smooth dense coating structure with a lower surface roughness and fine grain size, the average surface roughness (RSa) values are only 0.118–0.869 μm, and the corresponding surface area growth rate (Sdr) values are 3.85–80.19 %. Increasing the deposition temperature is beneficial for the transition of low melting point compounds of the coating surface to high melting point compounds, and extending the hot dip time is profit for the diffusion and enrichment of Al atoms on the coating surface. Besides, increasing the deposition temperature or time can also promote the growth of Al4Mo grains, thereby significantly increasing the coating thickness. When the deposition temperature is 750 °C, the thicknesses of Al4Mo and Al8Mo3 layers increases in a parabolic law with deposition time, and the Kp values both of them are 3.46 × 10−13 m2/s and 1.47 × 10−15 m2/s, respectively. The growth of the coating depends on the continuous diffusion of Al atoms towards the substrate direction, and the difference in chemical potential between Al atoms in each phase is the main driving force for coating growth.

INVESTIGATION OF ELECTROEROSION MACHINING PERFORMANCE OF METAL MATRIX COMPOSITE MATERIALS PRODUCED USING STIR AND INDIRECT SQUEEZE METHOD

In this study, metal matrix composite (MMC) materials were made with an aluminum matrix (AA7075 alloy) and reinforcement silicon carbide (SiC) elements using molten metal stir and indirect squeeze casting. SiC was used as a reinforcing element in the making of MMC material in different amounts (10%, 14%, and 18%) by mass. Electro Discharge Machining (EDM), cut depth (0.5 mm), three different pulse-on times, three different discharge current values, and a fixed pulse-off time (20 s) were used to machine MMC materials. The effects of machining parameters on machining time, average surface roughness, hole diameter, and material wear difference after machining were studied. As a result of the study, the composite material with 75 [Formula: see text]s pulse-on time, 6A current value, and 10% reinforcement element had the lowest machining time, the largest hole diameter, and the smoothest average surface. These machining parameters and materials also had the shortest machining time (5 min). Based on the signal-to-noise ratios, the best parameters for average surface roughness, hole diameter, Processing time, and material wear amount (MMC, discharge current value, and impact time) were found to be [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text], respectively. Based on the ANOVA results, the [Formula: see text]2 values for the average surface roughness, hole diameter, machining time, and material wear loss value were 99.3%, 98.7%, 77.8%, and 97.3%, respectively.

The effects of diode and Er:YAG laser applications on the surface topography of titanium grade 4 and titanium zirconium discs with sand-blasted and acid-etched (SLA) surfaces

BackgroundLaser application for the treatment of peri‑implantitis provides a variety of advantages; however, depending on the laser type and parameters, it may also have adverse effects on the implant surface qualities. This study's objective is to assess the effects of laser type and parameters on the surface properties of two different titanium-based implant materials: titanium Grade 4 (Ti-Grade 4) and titanium zirconium (Ti-Zr) discs with sand-blasted and acid-etched (SLA) surfaces under in vitro conditions. Material & methodSand-blasted and acid-etched discs made of titanium grade 4 (Ti-Grade 4) and titanium zirconium (Ti-Zr) were treated using 808 nm AlGaAs (diode) and 2940 nm Er:YAG lasers with varying parameters (i.e., diode laser in continuous wave mode, Er:YAG in short pulse mode, and Er:YAG in variable square pulse mode with four different doses). Then, the surface morphology and topography of the treated discs were characterized using scanning electron microscopy and optical profilometry. ResultsThe 3D surface topographies of discs treated with a high power Er:YAG laser displayed irregular peaks and deep valleys, indicating surface deterioration. The average surface roughness values (Sa) of both discs varied with laser type and parameters (3.55–4.80 µm for Ti-Grade 4 versus 3.25–4.5 µm for Ti-Zr). With diode laser applications, the topography features of the discs were preserved despite a small number of irregular valleys and peaks. However, the surface morphologies of the discs were dramatically altered by erosion and local melting because of the Er:YAG laser treatment. ConclusionDiode laser application appears to be the most reliable method for treating peri‑implantitis, as diode laser-treated implants retained their overall surface quality despite a small number of irregular peaks and valleys.

Eco-friendly tool-based electrochemical polishing of additively manufactured metallic components

The elevated surface roughness of metal additive manufacturing (MAM) parts detrimentally affects wear resistance, diminishes fatigue strength, and hampers cooling efficiency, which mandates post-processing. Electrochemical polishing is a non-contact and non-thermal post-processing technique but uses non-ecofriendly acidic baths and is ineffective in removing unmolten or partially molten metal particles. To address these challenges, we propose a novel approach using a flat nano-polished cylindrical tool as the cathode and an eco-friendly electrolyte for finishing a MAM component fabricated via atomic diffusion additive manufacturing (ADAM). Our study evaluates the effectiveness of this approach through numerical simulation and optimises the process through experimental analysis. The numerical simulation developed in COMSOL incorporates the surface roughness data of the ADAM part as the anode surface profile in the 2D simulation domain. The current density distribution, viscous layer formation, reduction in surface roughness and mass material removal rate (MRRg) are analysed from the simulation results. The experimental optimisation of parameters, including polishing time, inter-electrode gap (IEG), electrolyte flow, and electrolyte composition, resulted in a substantial decrease in the average surface roughness (Ra) value of the ADAM component by 95.91 %. The polished surface is more levelled, exhibiting a glossy finish with no waviness and fewer surface cracks. The EDS and XRD analysis portrayed the presence of passive films, indicating improved corrosion resistance. Repeating the experiment for rolled and milled surfaces with the same process parameters resulted in a similar reduction in the Ra value by 97.59 % and 94.73 %, respectively. The comparative analysis, of ECP on MAM, rolled, and milled surfaces, indicates the potential to achieve a similar notable improvement in surface finish, irrespective of the process history of the manufactured part for the same ECP parameters. Comparing the anode surface profiles, Ra values, and mass of material dissolved showed a close fit between experimental and simulation results. Our study highlights the feasibility of ECP with the flat tool electrode and eco-friendly electrolytes to reduce the surface roughness of an MAM component significantly.

Surface Integrity Study of AISI 1045 Material in Dry Machining Using Coated Carbide Tool

In metal cutting processes, the source of surface integrity deviation is a combination of several factors. The surface roughness parameter (Ra) is sufficient to determine the quality level of the surface packaging of a product, so it is widely used as a parameter to determine the surface packaging level of a product. Carbide tools dominate modern applications in the metalworking industry and are the preferred choice for metal cutting processes. Carbide tools can be improved through a coating process. In particular, the purpose of this study was to obtain surface roughness and optimum cutting conditions for dry machining of AISI 1045 materials using coated carbide tool when used in dry machining as well as for the development of research and development with research design analysis of the results of student practicum processes in laboratories, especially surface packaging material analysis. The material used is AISI 1045 with PVD TiAlN-TiN coated carbide tool. Combination machining process of cutting conditions, namely cutting speed, feed and depth of cut. Surface roughness test results on AISI 1045 test material with uncoated carbide tool surface roughness value = 9,042µm in cutting conditions: v= 235 m/min; f= 0.05mm/put; a=0.5mm; tc= 5.23 min. And the results of the surface roughness test on the AISI 1045 test material with PVD coated carbide tool with the best average surface roughness value = 6,135µm in cutting conditions: v=235 m/min; f=0.75 mm/put; a=1mm; tc=5.30 min.

Machining fiber-reinforced glass-epoxy composites with cryo-treated and untreated HSS cutting tools of varying geometries

Depending on the expanding application areas of glass fiber reinforced composite materials, quality machining of such materials also receives increasing interest. However, since the cutting tools used for machining such composites generally have standard geometric properties, both the life of the cutting tool and the quality of the machined composite workpiece are adversely affected by. In this study, the performance and the most optimum drilling geometries of untreated (UT) and cryo-treated&tempered (DCT&T) HSS cutting tools used for machining of fiber-reinforced glass-epoxy composites were investigated. Moreover, Taguchi experimental design was employed to reduce the number of experiments, and also the analysis of variance (ANOVA) and regression analysis were performed. Furthermore, XRD analysis and microhardness tests were applied to UT and DCT&T HSS cutting tools. From the highest and lowest delamination factor (Fd) values obtained using UT and DCT&T HSS drills, it was understood that DCT&T HSS drills achieved better results by 0.8% and 0.7%, respectively. According to average surface roughness (Ra) values obtained, the performances of DCT&T HSS drills were 14.76% (for the highest Ra value) and 2.69% (for the lowest Ra value), better than UT HSS drills. When the highest and lowest cutting force values were compared, it was seen that the cutting force values obtained using DCT&T HSS drills were 24.54% and 16.15% less than the cutting force values obtained using UT HSS drills, respectively. According to the S/N ratios for the cutting forces, the most optimum geometries of the cutting tool were found to be 128° point angle, 33° helix angle and 8° clearance angle, respectively. With respect to S/N ratios for Fd values, the most optimum geometries of the cutting tool were found to be 118° point angle, 26° helix angle and 8° clearance angle, respectively. Based on S/N ratios for Ra values, the most optimum geometries of the cutting tool were found to be 128° point angle, 26° helix angle and 8° clearance angle, respectively. On the other hand, as a result of the regression analysis, R2 values obtained over 90% show that the regression models are quite successful. Besides, it was observed (from SEM and thermal camera images) that the epoxy resins in the chips produced at high spindle speeds melted because of high temperature, which indicated that the integrity of the composite workpieces started to deteriorate.

Microstructural evolution and improved corrosion resistance of NiCrSiFeB coatings prepared by laser cladding

Abstract Inconel 625 (IN 625) is widespread in the manufacturing of critical components such as nuclear reactors, control rods, steam turbines, supercritical boilers, rotary shafts, aerospace engines, etc., that operate in severe harsh environments. However, if the service environments consist of sulphur (fuel tanks), chlorine (supercritical boilers and heavy water plants), H2S, HCl, etc., this alloy will suffer from localized corrosion attacks that minimize its resistance towards corrosion, followed by sudden failure. This study is aimed to facilitate the anti-corrosion characteristics of IN 625 by cladding it with Colmonoy 5 (NiCrSiFeB) alloy particles. The clad microstructure was revealed by micrographs captured by means of optical and field emission scanning electron microscopy followed by the nanoindentation study to analyze the hardness offered. Corrosion testing was carried out on both IN 625 and Colmonoy 5 clad samples at various intervals (0, 13, 27 and 56 h) for interrogating the corrosion behavior in terms of Tafel and impedance plots along with the surface roughness examination using scanning probe microscopy. The results showed that the clad region consists of dendritic microstructure along with the segregation of interdendritic Cr-rich precipitates after solidification. These interdendritic precipitates aid in improving the hardness at the clad region. Moreover, the clad samples have better anti-corrosion characteristics because of the existence of dendritic and interdendritic phases compared to the IN 625 samples in terms of current density, polarization resistance and average surface roughness values.

Correlation Analysis of Surface and Physical Properties of Ophthalmic Lenses Containing Nanoparticles.

Since contact lenses directly contact the cornea, the surface roughness of the lens may cause various side effects. In addition, gold nanoparticles can realize a variety of colors and characteristics depending on their shape and size. In this study, the surface roughness of tinted lenses containing gold nanoparticles of various sizes was analyzed using atomic force microscopy (AFM) at aspect ratio(surface to volume ratio) ranging from 1:1 to 1:10. The characteristics of the lenses were then confirmed. As a result, tinted lenses with different colors depending on the size of the gold nanoparticles were manufactured. The surface roughness of the lens decreased with increasing size of the gold nanoparticles. However, at aspect ratio of 1:10, increase in surface roughness was observed. In addition, it was confirmed that the wettability and antibacterial properties of the lens had the same effect according to the average surface roughness value. Therefore, it was confirmed that the addition of gold nanoparticles reduced the surface roughness of the lens, which had a great effect on properties such as wettability and antimicrobial properties of the lens. The produced copolymer controls the surface roughness of the lens, and thus it is judged that it can be used as a material for various ophthalmology applications.

AŞINDIRICI SU JET TORNALAMA ÇALIŞMA PARAMETRELERİNİN ABS VE PLA 3D BASILI PARÇA MALZEMELERİNİN YÜZEY PÜRÜZLÜLÜĞÜNE ETKİSİ

In this study, PLA and ABS materials produced by 3D printing with 14 mm diameter and 300 mm length were processed by turning with abrasive water jet machining. The effect of processing parameters with abrasive water jet on the surface roughness was investigated. The processing parameters are nozzle feed rate (60-210 mm/min), abrasive flow rate (150-225 g/min), chuck turning speed (75, 125, 175 and 225 RPM) and nozzle distance (3, 5, 7 and 9 mm). Experimental studies have shown that the increase in nozzle feed rate (from 60 to 210 mm/min), abrasive flow rate (from 150 to 225 g/min) and nozzle distance (from 3 to 9 mm) results in average surface roughness values increased by 26%, 35% and 19%, respectively. It was concluded that the increase in the rotation speed of the mirror (from 75 RPM to 225 RPM) resulted in a 17% decrease.

Enhancement of Surface Properties of 316L Stainless Steel with Silver Nanoparticles using Airbrush Spray Process

In this study, the surfaces of 316L stainless steel, which is frequently preferred in biomedical applications, were modified with silver nanoparticles (Ag NPs) to improve their antibacterial and anticorrosive properties. Firstly, Ag NPs were synthesized using a completely green a plant-mediated ultrasound-assisted synthesis method and characterized. Next, Ag NPs were coated onto the surface of the 316L with the airbrush spray technique. The coated surfaces were examined by SEM, surface roughness, profilometer, optical microscope, electrochemical corrosion, and disk diffusion analyses. The average surface roughness values of the surface modified samples were found to be moderately suitable for use in biomaterials while exhibiting corrosion resistance and antibacterial resistance. The Ag NPs coating offers significant potential for biomedical applications.

Circular Production, Designing, and Mechanical Testing of Polypropylene-Based Reinforced Composite Materials: Statistical Analysis for Potential Automotive and Nuclear Applications.

The circularity of polymer waste is an emerging field of research in Europe. In the present research, the thermal, surface, mechanical, and tribological properties of polypropylene (PP)-based composite produced by injection molding were studied. The pure PP matrix was reinforced with 10, 30, and 40% wt. of pure cotton, synthetic polyester, and polyethylene terephthalate post-consumer fibers using a combination of direct extrusion and injection molding techniques. Results indicate that PP-PCPESF-10% wt. exhibits the highest value of tensile strength (29 MPa). However, the values of tensile and flexural strain were lowered with an increase in fiber content due to the presence of micro-defects. Similarly, the values of modulus of elasticity, flexural modulus, flexural strength, and impact energy were enhanced due to an increase in the amount of fiber. The PP-PCCF-40% wt. shows the highest values of flexural constant (2780 MPa) and strength (57 MPa). Additionally, the increase in fiber loadings is directly proportional to the creation of micro-defects, surface roughness, abrasive wear, coefficient of friction, and erosive wear. The lowest average absolute arithmetic surface roughness value (Ra) of PP and PP-PCCF, 10% wt., were 0.19 µm and 0.28 µm. The lowest abrasive wear value of 3.09 × 10-6 mm3/Nm was found for pure PP. The erosive wear value (35 mm3/kg) of PP-PCCF 40% wt. composite material was 2 to 17 times higher than all other composite materials. Finally, the single-step analysis of variance predicts reasonable results in terms of the p-values of each composite material for commercial applications.

Effects of etchant concentration and process temperature in chemical milling of 430 stainless steel with FeCl3

In modern manufacturing application, chemical milling is a typical nontraditional machining method to remove material from surface of workpiece. The most commonly used chemical solution which is called etchant is ferric chloride (FeCl3) in surface chemical milling of iron based alloy and various etchant concentrations can be used to corrode the desired section of material. In this study, immerse type chemical milling process is employed for stainless steel (430 type) with FeCl3 etchant. The effects of etchant concentration and process temperature (25 °C and 50 °C) have been examined experimentally. It was observed that the process temperature improved surface chemical milling performance. Moreover, chemically milled surface quality was investigated and average surface roughness values have been obtained.