Optical Profilometer Research Articles

Analysis of FS and Surface Roughness in Heat-Polymerized Poly Methyl Methacrylate Acrylic Resin Reinforced with Different Concentrations of Glass Fibers and Polypropylene Fibers: A Laboratory Study Using EDX and SEM

This study aimed to evaluate the flexural strength (FS) and surface roughness (Ra) of heat-polymerized poly methyl methacrylate (PMMA) acrylic resin reinforced with glass fibers (GF) and polypropylene fibers (PPF) in different concentrations. One hundred heat-cured PMMA resin samples were prepared and randomly allocated into five groups based on fiber reinforcement (n = 20). Group 1 had no fiber reinforcement, Group 2 had 0.5% silanized GF reinforcement, Group 3 had 1% silanized GF reinforcement, Group 4 had 0.5% silanized PPF reinforcement, and Group 5 had 1% silanized PPF reinforcement. Fatigue load was applied through artificial aging. FS testing of fifty samples was performed using a universal testing machine, and Ra was analyzed using an optical interferometric profilometer. Specimens were selected for SEM and EDX analysis. To find the differences among the studied groups, one-way analysis of variance and post hoc Tukey’s test were utilized. The results showed that Group 5 (1% PPF reinforcement) presented the highest fracture resistance (90.1±9.8 MPa), while the minimum FS scores were observed in Group 1 (no reinforcement) (59.2±7.1 MPa). Group 3 (1% GF reinforcement) exhibited the highest values of surface roughness (1.99±0.1992), whereas the lowest roughness scores were observed in Group 1. The study concluded that incorporating 0.5% PPF into the resin denture is a viable option for reinforcing the prosthesis without increasing surface roughness.

Optical Studies of Silver Oxide Deposited Thin Films Using the RF Sputtering Technique

Background/Objectives: Silver Oxide is an efficient material because it is used in batteries. Apart from this, it is a moderate oxidizing agent in a variety of processes including the oxidation of aldehydes to carboxylic acids. The objective of the study is to synthesize silver oxide films by RF sputtering technique so that synthesized films can be inserted in the spectrophotometer for optical study. Methods: Silver Oxide films were deposited on Fluorine-doped Tin Oxide (FTO) glass using Radio Frequency (RF) sputtering method and annealed at 200 °C, for two hours, and then it was used in DK2 Ratio recording Spectrophotometer to analyze absorption and transmission data. Findings: The thickness of the films was measured using a non-contact optical Profilometer, in the range of (42– 660) nm. The films were subsequently exposed to optical characterization, revealing exceptionally low transmittance and high absorbance. The band gap is estimated to be 2.2 eV. The X-ray diffraction (XRD) studies reveal that the material is crystalline and Miller indices have also been determined. The morphology and topography of the thin films were analyzed using Field Emission Scanning Electron Microscope (FESEM) and the chemical composition was estimated using EDS. Novelty: The present work reveals that the optical properties are highly dependent on the thickness and the material distribution. The direct band gap energy is evaluated from the absorption spectrum which comes out to be 2.2 eV. The XRD spectra synthesized Silver Oxide films are crystalline in nature. Keywords: Silver Oxide, Band gap, XRD, FESEM

To investigate the effect of discharge energy and addition of nano-powder on processing of micro slots using EDM assisted µ-milling operation

ABSTRACT Micro-electric Discharge-Milling (µ-ED-M) is a non-contact process that uses an electrical spark to remove the material from a submerged workpiece with an electrode in a dielectric. The present paper focuses on optimizing process energizing (Capacitor, Voltage) and process stabilizing (Tool Travel Speed, Nano-Powder) parameters for controlling the size and surface characteristics of micro-crater. The present work focuses on the effect of nano-powder concerning dimensional aspects and surface characteristics at high and low capacitance levels. A µ-slot has been generated on the copper material by a tungsten carbide electrode. The experimentation is performed with two capacitor levels and three voltage and tool travel speed levels using full factorial design technique using with and without mixing of nano-powder in dielectric. The desirability functional multi-objective optimization approach is used to analyze the MRR, TWR, Width, and Depth. Field emission scanning electron microscopy (FESEM), non-contact optical profilometer, and x-ray diffraction (XRD) techniques are used to analyze the surface morphology of machined surfaces. The ANOVA is used to optimize the results; at low discharge energy, tool travel speed contributes 41% and promotes a higher thickness of recast layer 12.7 µm, whereas high discharge energy and nano-powder concentration contribute approx.—36% with 8.56 µm of recast layer.

Experimental study of the surface finishing of CNC magnetic abrasive finishing based on ANN

ABSTRACT CNC Magnetic Abrasive Finishing (CNC MAF) is famous for aluminium sheet processing. This study used an artificial neural network (ANN) analytical model with a Bayesian regularisation algorithm (BR) to examine how machine parameters (rotation speed, feed rate, depth of cut, and several passes) affect surface roughness during CNC MAF of aluminium sheet. Experimental and quantitative data proved its prediction ability. ANN model to select the best machine parameters for low surface roughness. The perfect numerical solution was experimentally tested, and surface morphology and roughness were used to evaluate processing quality under optimal machine parameters. The ANN model is also compared to Taguchi L16 for prediction and optimisation. Compared to ANN, prediction and optimal surface finishing mean absolute error are 96% lower. The results show that the ANN model is better at studying machine configuration during CNC MAF of Al sheet. SEM and 3D Optical profilometer were also used to analyze the Al sheet. The UV-VIS Spectrophotometer measures Al polished sample reflectance at 200–700 nm.

Diatom frustule-inspired elastic metamaterials

Although a universally accepted definition of elastic metamaterials does not exist yet, the latter are often associated to man-made or artificially engineered media possessing properties typically not available in Nature. Pioneering studies have recently demonstrated that complex structural organizations, often arranged in a periodic and/or gradient manner and spanning multiple length scales, typically found in many biological systems, exhibit extraordinary absorption/reflection functionalities enhanced by local resonances or Bragg scattering mechanisms. This has opened the road to new designs of bio-inspired metamaterial. In this context, here we investigate the elastic dynamic response of diatom frustules, i.e., the exoskeleton structures of photosynthetic algae ubiquitously present throughout the planet in water environments. Firstly, we analyse and record their structural arrangement in nano- and micro- scales by using the Scanning Electro Microscopy (SEM) and the optical profilometer. The results of the analysis are transferred to the metamaterial design. Secondly, through numerical models, we show the possibility of certain frustule-inspired geometries to behave as frequency selective elastic filters thanks to the presence of elastic bandgaps. The work herein contributes to the perspective of elastic metamaterials inspired by Nature.

Quantitative evaluation of pyramid belt wear using light-reflection characteristic of agglomerate coating and image processing

As a new generation of coated abrasive products with a unique pyramid-shaped structure, pyramid belt offers finer and more uniform grinding effects, and has been increasingly applied in precision grinding. However, belt wear occurs inevitably, challenging the control of shape accuracy and surface quality of ground components. Current research on pyramid belt wear is relatively limited, still lacking a universal, rapid method for observing and evaluating belt wear. In response, this paper proposes a quantitative evaluation method for pyramid belt wear using light-reflection characteristic of agglomerate coating and image processing. Firstly, a detailed analysis of the wear types and characteristics of pyramid belt is conducted. Then, focusing on the agglomerate flat wear, a method utilizing the light-reflection characteristic of agglomerate coating for observing belt wear morphology is proposed, enabling clear image capture of belt wear contours. Based on this, a wear coefficient based on the geometric characteristics of agglomerate is defined, and a quantitative evaluation method for belt wear using image processing is further proposed. The wear experiment of the belt is conducted on a robotic belt grinding platform, and experimental results show that the evaluation deviation of the proposed method from the evaluation results based on optical profilometer is within 5% at a 95% confidence interval, demonstrating the effectiveness of this method. Additionally, this method has advantages such as high computational efficiency, low cost, and good usability. Finally, the temporal evolution processes and spatial distribution patterns of belt wear and material removal rate are investigated and analyzed.

Effect of laser irradiation during in-office tooth bleaching on surface properties of resin-based restorative materials.

This study evaluated the changes in surface properties of three resin-based restorative materials after two laser-assisted, in-office tooth bleaching protocols using erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) or diode (980nm) lasers. A nanohybrid composite (Enamel Plus HRi), a Bis-GMA-free composite (Enamel Plus HRi Bio Function), and a resin-matrix CAD-CAM ceramic (Shofu Block HC) were tested. Forty specimens for each material were prepared and divided into four groups (n=10/group). The control specimens did not undergo any bleaching treatment, whereas group 2 received bleaching with 40% hydrogen peroxide (H2O2), while groups 3 and 4 underwent the same bleaching procedure with the use of diode (980nm) or Er,Cr:YSGG lasers, respectively. Surface microhardness and roughness measurements were conducted using a Vickers tester and an optical profilometer. Microhardness was lower in bleached specimens, with the nanohybrid composite exhibiting the largest difference from the no bleaching group. For the Bis-GMA-free composite the microhardness difference between no bleaching and laser-assisted bleaching were smaller than seen for the conventional bleaching technique. Surface roughness was higher in bleached specimens, with nanohybrid composite showing the largest differences from the control specimens. The examined laser-assisted tooth bleaching protocols were found not to impact surface microhardness and roughness of the tested resin-based specimens and they are deemed suitable for clinical use.

Telosma cordata and Zephyranthes candida mediated Green Synthesis of Zinc Oxide Nanoparticles using Plant Extract

The current research is focused on the production of zinc oxide nanoparticles utilizing eco-friendly bio-reductants derived from the leaves of Telosma cordata and Zephyranthes candida. Ultraviolet-visible (UV-VIS) spectroscopy is employed for quantitative analysis based on the absorption of light by the analyte. FT-IR is utilized to characterize the zinc oxide nanoparticles, identifying bio-functional groups present on their surface. X-ray diffraction (XRD) patterns confirm the hexagonal phase and crystalline size of the nanoparticles. Thermal gravimetric analysis was conducted to assess the thermal stability of the nanoparticles. Studies used optical profilometer for the topography and roughness of nanoparticles. The-synthesized nanoparticles also demonstrate notable antibacterial activity. The results of the study show that the plant extracts have several naturally occurring bioactive compounds that could be effectively utilized in the production of nanoparticles.

Depth of Cure, Surface Characteristics, Hardness, and Brushing Wear of 4 Direct Restorative Materials in Paediatric Dentistry

Aim: The study aimed to compare the depth of cure, hardness, surface roughness, and wear resistance of four restorative materials used in pediatric dentistry: FUJI IX GP FAST, RivaSilver, SDR flow+, and Vertise Flow. Materials and Methods: The depth of cure was measured per ISO 4049 standards using a digital caliper, with 15 samples of each material. Hardness was evaluated using a Vickers indenter under a 10 N load for 20 s. Surface roughness was assessed before and after acid exposure using an optical profilometer according to ISO 4288. Brushing wear resistance was analyzed by subjecting samples to 20 and 60 min of brushing, followed by roughness measurements. Statistical analysis was performed using independent sample t-tests to determine the significance of differences between the materials, with p-values < 0.05 considered significant. Results: SDR flow+ exhibited the highest depth of cure with an average of 3.5 mm (±0.2 mm), significantly higher than Vertise Flow at 2.8 mm (±0.3 mm) (p < 0.001). Hardness testing revealed SDR flow+ had the highest average hardness (85 HV ± 4 HV), while Vertise Flow had the lowest (72 HV ± 5 HV) (p < 0.001). Surface roughness increased significantly after acid exposure for RivaSilver (from 1.2 μm ± 0.12 μm to 1.6 μm ± 0.15 μm, p = 0.007) and for SDR flow+ (from 0.85 μm ± 0.08 μm to 1.3 μm ± 0.14 μm, p = 0.001). Brushing wear resistance was highest in RivaSilver (Ra increase from 1.2 μm to 1.4 μm ± 0.11 μm) and lowest in FUJI IX GP FAST (Ra increase from 1.5 μm to 1.9 μm ± 0.15 μm, p < 0.001). Conclusions: The study demonstrates significant differences in performance among the tested materials. SDR flow+ showed a superior depth of cure and hardness, making it suitable for high-stress applications. However, all materials displayed increased surface roughness following acid exposure and brushing, with FUJI IX GP FAST showing the highest wear. These findings highlight the need to select restorative materials based on the specific clinical demands of pediatric patients, considering both their mechanical properties and resistance to wear and acid.

Mucus-inspired biomass-derived carbon dots-based solvent-free nanofluid with polyelectrolytes networks toward excellent green lubrication

Mechanical friction and wear account for 23 % of global energy, highlighting a need for eco-friendly lubricants. Drawing inspiration from marine organisms' adsorption proteins, we have developed carbon dots-based solvent-free nanofluid. Incorporating hydrophilic polyelectrolytes, the nanofluid forms three-dimensional adsorption-lubrication networks, leveraging carbon dots' strong chelating affinity, synergistically enhancing lubrication. Using the UMT-3 TriboLab and a 3D optical profilometer, we assessed the tribological performance of nanofluid and remarkably reduced the friction coefficient by 47.3 % and wear rate by 90.8 % compared to PEG 200 (Polyethylene Glycol with an average molecular weight of 200). Additionally, the infrared camera detected that nanofluid as water additives, significantly reduce wear and heat generation, decreasing temperature rise by 4.7 times. This biomimetic approach paves the way for green, oil-free, and high-performance water-based lubrication technologies.

Novel usage of perinone polymer as solid contact in ion-selective electrodes

The paper presents the use of a new perinone polymer (PPer) as an intermediate layer and the development of a new type of potassium ion-selective electrodes with solid contact. The PPer layer was applied to the surface of a glassy carbon electrode using potentiodynamic polymerization from an electrolyte solution containing perinone precursors (Per). Subsequently, the surface of the electrode after application of the polymer was examined using a microscope and an optical profilometer. To check the quality of the prepared ion-selective electrodes, a series of tests were carried out and the analytical and electrical parameters of the electrodes were determined. Electrode modifications using PPer improved the electrode parameters, especially the stability and reversibility of the potential, compared to the control electrode covered only with an ion-sensitive membrane. The best electrode was the electrode modified with PPer applied in 10 cycles, which, as a result of the modification, allowed better parameters to be obtained – slope 58.86 mV/decade, LOD 1.2 × 10−6 M, linearity range 5 × 10−6 – 1 × 10−1 M. A very low short-term potential drift value of 2.7 × 10−4 mV/s was obtained as well as an extremely satisfactory SD value of 1.1 mV from E0 measurements. The modification also improved electrical properties and gave a negative result of the water layer test.

Rapid surface modification of PEEK by ambient temperature sulfonation for high shelf-life biomedical applications

The aim of this study is to develop a rapid, simple, and economical surface treatment process for Poly (ether-ether-ketone) (PEEK) using concentrated sulfuric acid. PEEK is a biocompatible material, with a bonelike elastic modulus and is mechanically superior to other implant materials like titanium, stainless steel etc. This property brings PEEK to limelight as a promising alternative for bone implants. However, a strong challenge is observed of osseointegration mainly due to its inert surface behavior and poor hydrophilicity. Chemical surface modification is considered as one of the best ways to bioactivate the PEEK surface. In this work, two different sulfonation treatment methodologies have been designed and the effect of reaction time is systematically studied over its changing surface properties and favorable cellular growth. In one treatment, only rapid sulfonation is implemented while in other treatment processes, scaffolds are treated with NaOH solution to terminate the sulfonation process. The modified PEEK surface is next evaluated using Fourier transform infra-red spectroscopy (FTIR), contact angle, optical profilometer and scanning electron microscopy to ascertain its behavior. The modified surface is observed to possess higher hydrophilicity, higher surface roughness and high porosity. No significant difference in hydrophilicity is observed for over a month once treated, showing permanency in modification. A 90 second treatment is observed to have the highest hydrophilicity and thus selected for cellular integration studies. No sign of cell toxicity was observed in the modified surfaces, which also showed improved protein adsorption, cell viability, cell adhesion, and proliferation compared to untreated PEEK.The proposed chemical modifications are promising techniques for a rapid, easy, and economical bioactivation of PEEK polymer for improved cellular activity.

A Comprehensive Evaluation of Electrochemical Performance of Aluminum Hybrid Nanocomposites Reinforced with Alumina (Al2O3) and Graphene Oxide (GO)

The electrochemical performance of in-house developed, spark plasma-sintered, Aluminum metal–matrix composites (MMCs) was evaluated using different electrochemical techniques. X-ray diffraction (XRD) and Raman spectra were used to characterize the nanocomposites along with FE-SEM and EDS for morphological, structural, and elemental analysis, respectively. The highest charge transfer resistance (Rct), lowest corrosion current density, lowest electrochemical potential noise (EPN), and electrochemical current noise (ECN) were observed for GO-reinforced Al-MMC. The addition of honeycomb-like structure in the Al matrix assisted in blocking the diffusion of Cl− or SO4−2. However, poor wettability in between Al matrix and Al2O3 reinforcement resulted in the formation of porous interface regions, leading to a degradation in the corrosion resistance of the composite. Post-corrosion surface analysis by optical profilometer indicated that, unlike its counterparts, the lowest surface roughness (Ra) was provided by GO-reinforced MMC.

Comparison of Various Surface Treatment Procedures on the Roughness and Susceptibility to Staining of Provisional Prosthodontic Materials.

Esthetically pleasing temporary prostheses are often necessary for extended periods in a variety of clinical scenarios. Adjustments to the occlusion or margins are commonly needed before cementing the temporary prosthesis. Therefore, it is clinically necessary to repolish the rough surface to avoid biological and esthetic issues associated with rough surfaces. The purpose of this in vitro study was to assess and compare the impact of various polishing protocols on the surface roughness and color stability of three resin materials used for provisional crowns. A total of 150 specimens were fabricated from auto-polymerizing polymethyl methacrylate, bis-acryl composite, and Methyl methacrylate-LC resin using a stainless steel mold. Each material group was divided into five groups (n = 10) based on the applied surface treatment: positive control group (G1): no roughening or surface treatment, Negative control group (G2): acrylic bur-roughened surface without any polishing, the different surface treatment groups of silicon carbide and aluminum oxide stone polishing (G3), diamond-coated rubber twist (G4), and Surface Glaze (G5). An optical profilometer was used to assess the surface roughness of all samples. After undergoing 6000 cycles of thermocycling followed by immersion in a coffee solution for 15 days at 37 °C, color parameters were measured using a spectrophotometer both before and after a storage period to evaluate color differences. A two-way ANOVA test with α = 0.05 significance level was carried out to determine the impacts of both the materials utilized and the polishing protocol. Among the three types of resin examined, the bisacryl group exhibited superior surface quality in positive control groups, while PMMA resin demonstrated higher polishability. The diamond-coated rubber twits resulted in lower Ra values of 0.36 (0.01) µm, 0.52 (0.11) µm, and 0.28 (0.05) µm for PMMA, BAMA, and MMLC resins, respectively. The application of photo-polymerized surface glaze led to a plaque accumulation threshold of 0.2 µm across all resin groups. The greatest mean color change occurred in the negative control group, indicating a propensity for more staining on rougher surfaces. The Bisacryl resin exhibited higher ΔE values, whereas PMMA showed better color stability. The lowest ΔE values were found when the surface glaze was applied to all of the provisional crown resins. Untreated Bisacryl resin exhibited the lowest Ra values, while PMMA resins demonstrated superior surface morphology after polishing. PMMA provisional crown resins showed increased resistance to staining. The use of surface glaze enhanced both smoothness and color stability on the surfaces.

Mechanical properties of 3D-printed resin denture teeth: An in vitro study.

The purpose of this study was to compare the wear, fracture strength, and mode of failure of various brands of 3D-printed resin denture teeth with prefabricated acrylic resin. Additionally, the study aimed to analyze the different modes of failure exhibited by these teeth. The study utilized 90 3D-printed and 30 prefabricated, 3D-printed resin teeth from three brands: L = Optiprint Lumina, A = ASIGA DentaTooth, P = Power resins, along with prefabricated acrylic teeth from M = Major Super Lux. Each of the 30 samples per main group was divided into two subgroups: The first subgroup samples (M1, A1, L1, P1) were subjected to thermal cycling and mechanical loading; M2, A2, L2, and P2 were not aged and tested directly. A scan of a prefabricated acrylic tooth was taken using an intraoral scanner, and then the STL file was printed using an Asiga 3Dprinter. The specimens underwent aging to simulate 5 years of clinical use with 10,000 thermal cycles and 1,200,000 dynamic load cycles on a chewing simulator. Surface roughness parameters (Rz, Ra, Rq) were measured using a 3D Optical Profilometer, fracture resistance was assessed using a universal testing machine, and SEM analysis was performed to observe failure modes. Statistical analysis using T-test, one-way analysis, and two-way analysis processed by the Statistical Package for Social Sciences (SPSS) software version 23.0 (SPSS: Inc., Chicago, IL, USA) was done with a level of significance set at <0.05. The results showed that the difference in surface roughness parameters (Rz, Ra, Rq) before and after aging for Group M, Group A, Group L, and Group P was statistically significant (p < 0.05). Two-way ANOVA for wear resistance between aging and groups on dependent variable Rz (p = 0.002), Ra (p = 0.001), Rq (p = 0.001) were significant. Multiple comparisons for surface roughness parameters showed Group A and Group L were lower than Group P and Group M (p < 0.05). For fracture strength, One-way ANOVA showed a significant difference between groups for fracture strength either without or after the aging procedure (p < 0.05). Multiple comparisons for fracture strength without aging showed no significant difference between Group M, Group A, and Group L (p > 0.05). After the aging procedure fracture strength for Group M was higher than Group A, Group L, and Group P (p < 0.05). 3D-printed resin teeth showed a greater and comparable wear resistance to prefabricated acrylic teeth. Fracture strength was comparable between prefabricated acrylic teeth and 3D-printed resin (Asiga and Lumina) before aging, but after aging 3D-printed resin teeth showed less fracture strength.

Enhancing of Surface Quality of FDM Moulded Materials through Hybrid Techniques.

With the rapid advancement of 3D-printing technology, additive manufacturing using FDM extrusion has emerged as a prominent method in manufacturing. However, it encounters certain limitations, notably in surface quality and dimensional accuracy. Addressing issues related to stability and surface roughness necessitates the integration of 3D-printing technology with traditional machining, a strategy known as the hybrid technique. This paper presents a study of the surface geometric parameters and microstructure of plastic parts produced by FDM. Sleeve-shaped samples were 3D-printed from polyethylene terephthalate glycol material using variable layer heights of 0.1 mm and 0.2 mm and then subjected to the turning process with PVD-coated DCMT11T304 turning inserts using variable cutting parameters. The cutting depth was constant at 0.82 mm. Surface roughness values were correlated with the cutting tool feed rate and the printing layer height applied. The selected specimen's microstructure was studied with a Zeiss EVO MA 15 scanning electron microscope. The roundness was measured with a Keyence VR-6200 3D optical profilometer. The research results confirmed that the additional application of turning, combined with a reduction in the feed rate (0.0506 mm/rev) and the height of the printed layer (0.1 mm), reduced the surface roughness of the sleeve (Ra = 1.94 μm) and increased its geometric accuracy.

Effects of UV Postcuring Times on the Color Stability, Surface Properties and Conversion of 3D-printed Temporary Resin Composites.

To evaluate the effects of UV postcuring times on color stability (CS), surface properties (wettability [°] and surface roughness [Ra]), and conversion of 3D-printed resins for temporary restorations. Disc-shaped specimens (10.0×3.0 mm) and maxillary central incisors (8.2×10.3 mm) were fabricated using provisional 3D-printed resin (PriZma Bio Prov [PZ] and PrintaX AA TEMP [PX]) in A2 shade and subjected to UV postcure times of 0 (T0), 5 (T1), 10 (T2), and 15 (T3) minutes (n=15). The incisors were used for CS evaluation with a colorimeter. In contrast, discs were used to measure the contact angle using the sessile drop method, surface roughness with an optical profilometer, and degree of conversion with FT-NIR. For CS, Ra, contact angle, and degree of conversion, a two-way ANOVA with Bonferroni post-hoc test (α=0.05) was used. PX resin demonstrated greater color stability than PZ (p=0.001). Long UV postcuring times (10 to 15 minutes) will increase the contact angle (p=0.013) and stabilize the degree of conversion (p=0.01), while 5 to 10 minutes of UV postcuring will provide better surface smoothness (p=0.04) of both resins. Long UV postcuring times (10 to 15 minutes) lead to greater alterations in color, contact angle, and stability of the degree of conversion, while 5 to 10 minutes lead to a smoother surface of the 3D-printed temporary resins.

A Comparative Evaluation of Antifungal and Physical Properties When Nanoparticles Are Incorporated Into the Tissue Conditioner: An In Vitro Study.

Objective The objective of this in vitrostudy was to comparatively evaluate the antifungaland physical properties of tissue conditioner incorporated with nanoparticles (NPs) of different types and concentrations. Materials and methods A total of 198 tissue conditioner samples were used in this study. The samples were categorized into a control group, namely, tissue conditioner without NPs (Group 1), and test groups, namely, tissue conditioner incorporated with zinc oxide (ZnO) NPs (Group 2) andmagnesium oxide (MgO) NPs (Group 3). The antifungal properties and surface roughness of the samples were evaluated. The groups were further subdivided into seven subgroups: control (without NPs), 5% ZnO NPs, 10% ZnO NPs, 15% ZnO NPs, 3% MgO NPs, 5% MgO NPs, and 7% MgO NPs by weight. Surface roughness was measured using an optical profilometer,and antifungal activity was measured in terms of the diameter of the inhibition zone (DIZ) using the well diffusion method over seven days. Results The result showed that the 5%ZnO NPs subgroup had the lowest mean surface roughness, whereas the 15% ZnO NPs subgroup had the highest antifungal activity. Increasing the concentration of NPsincreased the antifungal property, and there was a steady decrease in DIZ from day one to day seven in all test groups. Conclusion Our results showed that the incorporation of various concentrations of ZnO and MgO NPs into tissue conditioner samples positively affected their physical and antifungal properties. The highest antifungal activity was found in the 15% ZnO NPs subgroup, and the lowest surface roughness was found in the 5% ZnO NPs subgroup.

A novel approach for zero material loss (zero flash) and uniform cross-section during friction stir welding of dissimilar thickness Cu and Al alloys

A novel approach for getting a uniform weld cross-section and flash-free joint with the help of friction stir welding (FSW) is implemented. The influence of the tool tilt angle and rotational speed on the macrostructure, microstructure, and mechanical properties was investigated. Mechanical characterization techniques like an optical microscope, FESEM, profilometer, tensile test, bent test, and XRD analysis were used to evaluate the joint properties. A maximum tensile strength of 108.91 MPa was achieved, which led to a joint efficiency of 96.38 %. A maximum bending angle of 107° was achieved for samples S5 and S6. The Al/Cu mixed region in the stir zone displayed a maximum micro-hardness of 152.26 HV whereas a minimum micro-hardness of 33.57 HV was achieved in the HAZ along aluminium side. Welds prepared at a rotational speed of 540 RPM and a tool tilt angle of 4.5°results in an almost flash-free joint.

Tribological properties under dry and lubricated sliding conditions of TiSiN and AlTiCrN coatings deposited on gray cast iron

In internal combustion engines, the majority of friction losses and wear occur between the cylinder liners and piston rings. Hard coatings applied to cylinder liners can increase the efficiency of internal combustion engines by improving tribological properties. The gray cast iron cylinder liner was coated with TiSiN and AlTiCrN employing the cathodic arc deposition process. The coatings were examined using nanoindentation tests, scratch tests, an optical profilometer, a scanning electron microscope, an X-ray diffractometer, and energy dispersive analysis to assess their hardness, adhesion, and structural characteristics. The reciprocating test was carried out to assess the coatings' wear and friction characteristics under lubricated and dry sliding with a ball at varying normal loads. The hardness of the TiSiN and AlTiCrN coatings was 45 GPa and 18 GPa, respectively. The cohesion strength, adhesion strength, and crack propagation resistance of AlTiCrN coating were approximately 2, 1.3 and 2.5 times higher than those of TiSiN coating, respectively. Both coatings exhibited remarkable wear performance at high normal loads. Under dry sliding conditions at 25 N normal load, the wear rate of AlTiCrN and TiSiN coatings were nearly 33 and 20 times, respectively, lower than the uncoated substrate. Under dry sliding conditions, the TiSiN coating exhibited the lowest wear rate at low normal loads (5 N and 15 N), while the AlTiCrN coating performed best at high normal loads (25 N). In lubricated sliding conditions, the AlTiCrN coating consistently showed the lowest wear rate across all normal loads.