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A novel photopolymerizable (meth)acrylate oligomer syrup modified with ferulic acid (FA) was verified as an antimicrobial coating binder against a biofilm of Staphylococcus epidermidis. A solution-free UV-LED-initiated photopolymerization process of aliphatic (meth)acrylates and styrene was performed to prepare the oligomer syrup. The influence of ferulic acid on the UV crosslinking process of the varnish coatings (kinetic studies using photo-DSC) as well as their chemical structure (FTIR) and mechanical (adhesion, hardness), optical (gloss, DOI parameter), and antibacterial properties against S. epidermidis were investigated. The photo-DSC results revealed that FA has a positive effect on reducing the early occurrence of slowing processes and has a favorable effect on the monomer conversion increment. It turned out, unexpectedly, that the more FA in the coating, the greater its adhesion to a glass substrate and hardness. The coating containing 0.9 wt. part of FA exhibited excellent antimicrobial properties against S. epidermidis, i.e., the bacterial number after 24 h was only 1.98 log CFU/mL. All the coatings showed relatively high hardness, gloss (>80 G.U.), and DOI parameter values (30–50 a.u.). [ABSTRACT FROM AUTHOR]

Objectives: The present trial’s aim was to compare the remineralization potential of self-assembling peptide P11-4 combined with fluoride to that of fluoride varnish. Materials and methods: Twenty-eight participants with 58 incipient carious lesions were enrolled in the present trial. Participants were randomly divided into two groups with 14 participants and 29 incipient lesions in each group. Patients were assigned either to self-assembling peptide combined with fluoride (Curodont Repair Fluoride Plus™) or sodium fluoride varnish (NaF, Bifluorid 10) groups. Both agents were applied according to the manufacturer’s instructions on non-cavitated incipient carious lesions. Lesions were assessed by two calibrated and blinded assessors at baseline, and after one-, three- and six-months using a laser fluorescence device (DIAGNOdent). Results: Although laser fluorescence scores significantly improved in both groups over time (p < 0.05), no notable differences were evident between both groups at one-month (p > 0.05). Yet, at three- and six-months statistically lower laser fluorescence readings were evident in the self-assembling peptide combined with fluoride group in comparison to the fluoride alone group (p < 0.05). There was 60% less risk for caries progression for Curodont Repair Fluoride Plus™ when compared to NaF varnish after six months. Self-assembling peptide combined with fluoride was able to change 65.5% of non-cavitated carious lesions from DIAGNOdent score 3 (11–20) to score 1 (0–4). Fluoride varnish was able to change 13.8% of the lesions from score 3 to score 1 after six months. Conclusions: The self-assembling peptide combined with fluoride varnish showed higher remineralization potential than fluoride varnish alone for incipient carious lesions over a six-months follow up. Clinical relevance: The combination of self-assembling peptide P11-4 and fluoride could offer a new tool in managing incipient carious lesions. [ABSTRACT FROM AUTHOR]

Objective: Maintaining appropriate salivary levels of an active ingredient is challenging. Intraoral trays can be used to deliver medications for localized treatment. Based on previous successful daytime studies with a slow-release sirolimus varnish, the aim was to optimize intraoral appliances/trays for overnight use to deliver slow-release medications in a manner that maintains therapeutic salivary levels of the active ingredient to treat oral conditions. Method and materials: An acrylic tray appliance containing 0.5 mg of sirolimus in a sustained-release varnish was placed on six anterior teeth for 12 hours, in ten healthy volunteers. Whole unstimulated saliva was collected at 1, 2, 10, and 12 hours after application. Blood was collected at the time of recruitment to confirm eligibility, and 12 hours after device removal to measure sirolimus levels. Drug levels in the blood and saliva were analyzed. Slow- and fast-release formulations, varnish position (buccal, palatal, or lingual), and tray placement (mandibular or maxillary) were qualitatively compared. Participants evaluated the varnish and tray. Results: Moderate concentrations of sirolimus were detected in the saliva when the fast-release formulation was used. The highest levels were from the mandibular tray with lingual varnish application. Sialometry of all participants was within normal range, and the highest drug levels were detected when low flow was measured. No traces of the medication were found in the blood. Conclusions: Salivary concentrations of medications applied to an intraoral appliance are affected by the placement in the maxilla or mandible, varnish formulation, location of varnish, and salivation rate. These results may help optimize medication release following application to various oral devices. [ABSTRACT FROM AUTHOR]

Copyright of Paint & Coatings Industry (0253-4312) is the property of Paint & Coatings Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study provides an evaluation of MS3, a reduced polycyclohexanone resin, with key considerations for use as a picture varnish including solubility, removability, colour, and gloss and the stability of these factors. MS3 was first produced in 2016 as a replacement for the discontinued MS2A resin which was widely used as a conservation-grade picture varnish. Films of MS3 resin were artificially aged using UV-containing and UV-filtered light, representing the effects of daylight filtered through glass, and indoor museum lighting conditions respectively. Changes in colour and gloss of light-aged samples vs. control samples were measured, and solubility/removability was evaluated using selected solvents applied by hand-rolled swabs. FTIR spectroscopy was used to explore chemical changes of the varnish films following light ageing with respect to control samples. Empirical observations were made regarding the handling properties of MS3 dissolved in Stoddard solvent, and its behaviour as a retouching medium and varnish. The results suggest that MS3 exhibits a slight yellowing and a moderate increase in the polarity of solvent required for removal. No significant colour or solubility changes were observed in MS3 varnish films artificially aged using non-UV light. The results suggest that MS3 is a good substitute for MS2A resin for use as a picture varnish or retouching medium, based on the parameters measured. [ABSTRACT FROM AUTHOR]

Background: Fluoride is vital in dentistry for caries prevention, enhancing remineralization, and inhibiting bacteria. Incorporating fluoride into restorative materials like glass-ionomer cements, compomers, and giomers has significantly increased fluoride availability in the oral cavity. This review assesses how surface coatings influence fluoride release from various dental restorative materials. Methods: In December 2023, we conducted electronic searches in PubMed, Scopus, and Web of Science (WoS) databases. In the Scopus database, the results were refined to titles, abstracts, and keywords, while in PubMed, they were narrowed down to titles and abstracts. In WoS, the results were refined only to abstracts. The search criteria were based on the terms fluoride AND release AND (coating OR glaze OR layer OR film OR varnish) AND (composite OR glass OR compomer), following PRISMA guidelines and the PICO framework. Twenty-three studies were rigorously selected and analyzed for fluoride release from coated versus uncoated materials. Results: Surface coatings typically reduce the rate of fluoride release. Glass-ionomer cements had the highest release, followed by giomers and compomers. The initial release was greater in uncoated materials but stabilized over time, influenced by variables like artificial saliva and deionized water. Conclusions: Surface coatings generally decrease fluoride release rates from dental materials. Although initial rates are high, contributing to caries prevention, more standardized research is needed to better understand the impact of coatings and optimize materials for maximum preventive benefits. [ABSTRACT FROM AUTHOR]

The current work was developed focusing on the synthesis of new polymeric latexes through the in reactor oxidative polymerisation of chia oil alkyd resins using the miniemulsion process. These latexes have potential applications, primarily in coating applications. Initially, an oil length mixture was obtained from chia oil through saponification and acidification reactions. The resulting mixture was characterized by 1H-NMR and 13C-NMR, confirming the presence of unsaturation and the characteristic functional groups associated with this compound. Phthalic anhydride and glycerol (esterification reaction) were used in the synthesis of alkyd resin. Alkyd resins were obtained by varying the oil length content in its composition: 30% wt% oil length alkyd resin is called short alkyd resin, 43% wt% oil length is medium resin and 64% wt% is the long alkyd resin. The 1H NMR spectra of alkyd resins showed peaks indicative of the presence of groups coming from phthalic anhydride and glycerol, as well as unsaturations that varied in intensity according to the size of the resin (short, medium or long). The miniemulsions were obtained from alkyd resins demonstrating colloidal stability over 90 days and with stable miniemulsions the oxidative polymerisation of the alkyd resins was carried out in a high-pressure reactor with temperature and pressure control and in the presence of the radicalinitiator benzoyl peroxide (BPO) and oxygen. Based on 1H-NMR analysis, polymers are formed through the oxidative polymerisation of alkyd resins from chia oil using the miniemulsion process. These polymers can be used as a paint base with a low solvent fraction or no solvent, depending on the application, and without using heavy metals-based catalysts. [ABSTRACT FROM AUTHOR]

Copyright of Gazi Üniversitesi Fen Bilimleri Dergisi Part C: Tasarım ve Teknoloji is the property of Gazi University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Insoluble contaminants and varnish, resulting from oil degradation byproducts and sometimes depleted additive molecules, are initiated primarily due to thermal stress on the oil. This poses significant challenges in tribology, particularly for the lubrication systems of modern complex machinery, leading to severe debilitating effects such as loss of operating clearances and impaired heat transfer. Addressing varnish buildup is crucial, and timely oil analysis emerges as a valuable tool, offering essential insights into the oil degradation level and the potential presence of insoluble contaminants. Among the various laboratory testing methods available to assess varnish potential, colorimetric analysis, specifically Membrane Patch Colorimetry (MPC), is widely applied owing to its efficiency and cost-effectiveness. This study extends the application of MPC test principles, commonly utilized for turbine oils, to measure insoluble contaminants generated by degraded hydraulic fluids. Adhering to the ASTM D7843-21 standard, which stipulates the precision of this testing method for turbine oils is contingent upon the sample's incubation period, our investigation focuses on exploring modifications to the standard 72-hour incubation period. We aim to assess the viability of shortening or extending this duration for conducting MPC tests on used hydraulic fluids, thereby potentially enhancing the precision and relevance of MPC tests in hydraulic fluid analysis. [ABSTRACT FROM AUTHOR]

The objective of the study was to analyze the influence of coating treatments on sound propagation speeds in thin boards, along the longitudinal and radial directions of resonance wood. The samples studied were thin boards made of spruce and maple wood with dimensions of 240 mm × 80 mm × 4 mm (length × width × thickness) subjected to different coating treatments (oil-based varnish and alcohol varnish) as well as unvarnished samples, exposed to radiation UV, and specimens treated in the saline fog. The test method consisted of evaluating the propagation speeds of Lamb waves applied to thin plates, according to a semicircular test model, so that the results highlighted both the acoustic response in the longitudinal and radial directions as well as the variation in the anisotropy of the samples with the change in the sound propagation direction relative to wood fibers. Based on the statistical analysis, sound propagation speed profiles were obtained in each of the 38 directions analyzed for all wood samples. The results highlighted that the oil-based varnish led to a decrease in the speed of propagation in the radial direction, compared to the alcoholic varnish, whose major effect was in the longitudinal direction, on the spruce wood. On maple wood, increasing the number of varnish layers, regardless of the type of varnish, led to a decrease in the anisotropy ratio between the longitudinal and radial directions. [ABSTRACT FROM AUTHOR]

Varnish layers are optical coatings that act as physico‐chemical barrier between the historical paint layers and the environment. Understanding how varnish materials protect historical paintings over time and in the presence of humidity or organic vapors is of central importance for art preservation. However, probing the behavior of varnish after aging in real conditions remains a challenge. Here the question is addressed by "reshaping" the varnish material from the masterpiece of G. Bellini, the "Transfiguration", into an optical layer; coupling in situ Ultraviolet‐Visible (UV–vis) and Infrared (IR) ellipsometries, the chemical state is correlated, optical properties and swelling of the varnish in presence of water and organic vapors. It shows that the varnish material aged since the 1950s still exhibits effective water repellence. The methodology may be applied to other relevant historical systems beyond paintings and may help in establishing more efficient preservation strategies for historical artworks. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effects of mechanical and ultrasound-assisted stirring methods for varnish + components mixing on the varnish layer coating adhesion, surface roughness and glossiness. For this purpose, polyurethane, acrylic and polyester varnish systems were applied on three different wood types, namely Scots pine (Pinus sylvestris L.), Eastern beech (Fagus orientalis L.) and Mahogany (Khaya ivorensis), with mechanical and ultrasound-assisted mixing methods. In the mechanical mixing method, 3 and 5 minutes were applied, while in the ultrasonic mixing method, beside 3- and 5- minute stirring time, 80-watt, and 120-watt ultrasonic power was applied during mixing. When research results are generally evaluated, it cannot be said that ultrasound-assisted mixing method is superior to mechanical mixing method. However, the ultrasound-assisted mixing of varnish components at 80 watts for 3 minutes can be recommended.

Abstract Background The study objective was to examine the effect of arginine-sodium fluoride (Arg-NaF) varnish on preventing enamel erosion by acidic paediatric liquid medicaments (PLM). Methods The treatment groups were: 1) 2% Arg-NaF; 2) 4% Arg-NaF; 3) 8% Arg-NaF; 4) NaF; 5) MI (CPP-ACFP) varnishes; and 6) no varnish. The pH of PLM (paracetamol and chlorpheniramine) was measured at baseline and after immersing the Perspex® blocks coated with varnishes at 0 min, 30 min, 1 h, and 4 h. Seventy-two enamel specimens (n = 72) were randomly divided into 2 groups by PLM and further by treatment groups. Then, the specimens were pre-treated with varnishes and subjected to erosive cycles (5 min, 2×/day for 4 days) by PLM. After each erosive challenge, the specimens were stored in artificial saliva. At baseline and after 4 days, the specimens were assessed for surface roughness (Ra) using 2D-surface profilometric analysis (SPA) and atomic force microscopy (AFM). Additionally, the Ca/P ratio was determined using scanning electron microscopy with energy-dispersive X-ray spectroscopy. Paired samples dependent t-test, 1-way ANOVA and 2-way ANOVA with Bonferroni post-hoc tests were used to analyse data with the level of significance set at p 0.05). The Ra determined by AFM, at the post-erosive cycle with chlorpheniramine, when treated with 4 and 8% Arg-NaF was significantly lower than the other groups (p 0.05). With the chlorpheniramine post-erosive cycle, the Ca/P ratio for 4, 8% Arg-NaF and CPP-ACFP treated specimens was significantly higher than the baseline Ca/P (p

A novel photopolymerizable (meth)acrylate oligomer syrup modified with ferulic acid (FA) was verified as an antimicrobial coating binder against a biofilm of Staphylococcus epidermidis. A solution-free UV-LED-initiated photopolymerization process of aliphatic (meth)acrylates and styrene was performed to prepare the oligomer syrup. The influence of ferulic acid on the UV crosslinking process of the varnish coatings (kinetic studies using photo-DSC) as well as their chemical structure (FTIR) and mechanical (adhesion, hardness), optical (gloss, DOI parameter), and antibacterial properties against S. epidermidis were investigated. The photo-DSC results revealed that FA has a positive effect on reducing the early occurrence of slowing processes and has a favorable effect on the monomer conversion increment. It turned out, unexpectedly, that the more FA in the coating, the greater its adhesion to a glass substrate and hardness. The coating containing 0.9 wt. part of FA exhibited excellent antimicrobial properties against S. epidermidis, i.e., the bacterial number after 24 h was only 1.98 log CFU/mL. All the coatings showed relatively high hardness, gloss (>80 G.U.), and DOI parameter values (30–50 a.u.).

The objective of this study was to determine the effects of mechanical and ultrasound-assisted stirring methods for varnish systems on the varnish layer's surface hardness and surface scratch resistance. The study focused on polyurethane, acrylic, and polyester varnish systems, which were applied to three distinct wood types: Scots pine (Pinus sylvestris L.), Turkish beech (Fagus orientalis Lipsky), and African mahogany (Khaya ivorensis A. Chev.). The mixing processes included mechanical stirring for 3 and 5 minutes, as well as ultrasound-assisted stirring with differing power levels (80 W and 120 W) for 3 and 5 minutes. The highest surface hardness (175.10) was achieved using polyester varnish obtained by mechanical stirring for 3 minutes and applied to Turkish beech, while the lowest surface hardness (66.80) was observed for acrylic varnish obtained by 120 W ultrasound-assisted stirring for 5 minutes and applied to African mahogany. The highest surface scratch resistance (0.760 N) was observed with polyester varnish obtained by mechanical stirring for 5 minutes and applied to Scots pine, and also with acrylic varnish obtained by 80 W ultrasound-assisted stirring for 3 minutes and applied to Turkish beech. Overall, the findings suggested that the ultrasound-assisted mixing method generally fell short in terms of enhancing the varnish properties compared with the mechanical mixing technique. [ABSTRACT FROM AUTHOR]

Introduction: Depending on their terpenoid and phenolic constituents plant resins can be classified as diterpenoid, triterpenoid or phenolic resins; thereby the profile of diterpenes and triterpenes is considered as genus‐ or even species‐specific. Objectives: We aimed to develop a simple, rapid, inexpensive, sensitive and specific method for the identification of resin‐specific triterpenoid and phenolic compounds in plant resins using (HP)TLC [(high‐performance) thin‐layer chromatography] combined with APCI‐MS (atmospheric pressure chemical ionisation mass spectrometry) and post‐chromatographic detection reactions. Methods: Twenty resin samples from different plant species were analysed. Different extraction procedures, post‐chromatographic detection reagents as well as various sorbents and solvents for planar chromatography were tested. To evaluate the potential of the optimised (HP)TLC‐APCI‐MS methods, parameter such as limit of detection (LOD) was determined for selected marker compounds. Results: Our protocol enabled qualitative analyses of chemotaxonomic molecular markers in natural resins such as dammar, mastic, olibanum and benzoin. For the first time, the application of thionyl chloride‐stannic chloride reagent for a specific post‐chromatographic detection of triterpenes is reported, sometimes even allowing discrimination between isomers based on their characteristic colour sequences. For triterpene acids, triterpene alcohols and phenolic compounds, detection limits of 2–20 ng/TLC zone and a system precision with a relative standard deviation (RSD) in the range of 3.9%–7.0% were achieved by (HP)TLC‐APCI‐MS. The applicability of the method for the analysis of resin‐based varnishes was successfully tested on a mastic‐based varnish. Thus, the method we propose is a helpful tool for the discrimination of resins and resin‐based varnishes with respect to their botanical origin. In this study, we developed a simple, rapid, cost‐effective, sensitive and specific method for the identification of chemotaxonomic molecular markers in plant resins such as dammar, mastic, olibanum and benzoin using (HP)TLC combined with APCI‐MS and post‐chromatographic detection reactions. For the first time, the application of thionyl chloride‐stannic chloride reagent for a specific post‐chromatographic detection of triterpenes is reported, sometimes even allowing discrimination between isomers based on their characteristic color sequences. [ABSTRACT FROM AUTHOR]

Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is believed that old and used musical instruments have better accoustic than new fabricated ones. The nature of the type of varnish used on musical instruments it's a subject that has been debated for a long time. The main purpose of the paper is to analyze the effect of artificial aging on the color parameters of the varnish film used in violin varnishing. Thus, samples of resonance spruce wood from different classes of anatomical quality were studied, some covered with alcoholic varnish and others with oil-based varnish, in 5, 10, 15 layers. The color parameters were measured with a Konica Minolta colorimeter device, measurements being taken on the lacquered surface in 3 points, both before and during exposure to UV radiation for 1000 hours. The results highlighted the fact that the lightness and the redness are the parameters most affected by the effect of photo-degradation. The anatomical structure of the spruce wood (class A and D) is another factor that influences the intensity of the color changes of the varnish film. The anatomical structure of the spruce wood (class A and D) is another factor that influences the intensity of the color changes of the varnish film. In general, all color parameters have lower values on class D spruce wood (with wide annual rings), compared to class A wood (with narrow annual rings) whose color parameters are up to 7 - 10% higher. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The study objective was to examine the effect of arginine-sodium fluoride (Arg-NaF) varnish on preventing enamel erosion by acidic paediatric liquid medicaments (PLM). Methods: The treatment groups were: 1) 2% Arg-NaF; 2) 4% Arg-NaF; 3) 8% Arg-NaF; 4) NaF; 5) MI (CPP-ACFP) varnishes; and 6) no varnish. The pH of PLM (paracetamol and chlorpheniramine) was measured at baseline and after immersing the Perspex® blocks coated with varnishes at 0 min, 30 min, 1 h, and 4 h. Seventy-two enamel specimens (n = 72) were randomly divided into 2 groups by PLM and further by treatment groups. Then, the specimens were pre-treated with varnishes and subjected to erosive cycles (5 min, 2×/day for 4 days) by PLM. After each erosive challenge, the specimens were stored in artificial saliva. At baseline and after 4 days, the specimens were assessed for surface roughness (Ra) using 2D-surface profilometric analysis (SPA) and atomic force microscopy (AFM). Additionally, the Ca/P ratio was determined using scanning electron microscopy with energy-dispersive X-ray spectroscopy. Paired samples dependent t-test, 1-way ANOVA and 2-way ANOVA with Bonferroni post-hoc tests were used to analyse data with the level of significance set at p < 0.05. Results: The pH of PLM with 8% Arg-NaF was significantly higher than the other groups at 30 min and 4 h (p < 0.05). With paracetamol, no significant difference was observed between the baseline and post-erosive cycle measured enamel Ra (by SPA/AFM) and Ca/P ratio for all treatment groups (p > 0.05). The Ra determined by AFM, at the post-erosive cycle with chlorpheniramine, when treated with 4 and 8% Arg-NaF was significantly lower than the other groups (p < 0.05); except CPP-ACFP (p > 0.05). With the chlorpheniramine post-erosive cycle, the Ca/P ratio for 4, 8% Arg-NaF and CPP-ACFP treated specimens was significantly higher than the baseline Ca/P (p < 0.05). Conclusion: The 4%/8% Arg-NaF and MI varnish® application exhibit an enhanced preventive effect against low pH (pH < 3.0) PLM-mediated enamel erosive challenges compared to 5% NaF varnish. [ABSTRACT FROM AUTHOR]

Acacia mangium requires the addition of a finishing material to increase its resistance to weathering. Herein, the effectiveness of a nanocoating containing titanium dioxide nanoparticles (TiO2-NPs) as a finishing material for mangium wood was investigated. The coating material formulations used were oil-based (V1) and water-based (V2) varnishes with TiO2-NP concentrations of 1% (CT1), 5% (CT5), and 10% (CT10) (w/v). The uncoated and coated samples were subjected to weathering periods of 0, 2, and 4 months. The results showed that the addition of TiO2 nanoparticles to the V1 and V2 varnishes resulted in more gradual colour changes after the weathering period. The surface of the mangium wood also became smoother after being coated. However, the surface roughness increased with the duration of the weathering period. The wettability (K-value) of the sample decreased after coating, indicating that the coated sample was more hydrophobic than the uncoated sample. The results of a photocatalyst test, which analysed the effectiveness of the coatings, showed that the best coating material formulas were V1-CT10 and V2-CT10, as they degraded 75.21% and 71.03% of methylene blue content, respectively. Fourier transform infrared analysis showed that mangium wood did not undergo rapid weathering after the nanocoating treatment, as indicated by an insignificant decrease in the peak absorption intensity of the main structural functional groups of wood. [ABSTRACT FROM AUTHOR]

Insoluble contaminants and varnish, resulting from oil degradation byproducts and sometimes depleted additive molecules, are initiated primarily due to thermal stress on the oil. This poses significant challenges in tribology, particularly for the lubrication systems of modern complex machinery, leading to severe debilitating effects such as loss of operating clearances and impaired heat transfer. Addressing varnish buildup is crucial, and timely oil analysis emerges as a valuable tool, offering essential insights into the oil degradation level and the potential presence of insoluble contaminants. Among the various laboratory testing methods available to assess varnish potential, colorimetric analysis, specifically Membrane Patch Colorimetry (MPC), is widely applied owing to its efficiency and cost-effectiveness. This study extends the application of MPC test principles, commonly utilized for turbine oils, to measure insoluble contaminants generated by degraded hydraulic fluids. Adhering to the ASTM D7843-21 standard, which stipulates the precision of this testing method for turbine oils is contingent upon the sample’s incubation period, our investigation focuses on exploring modifications to the standard 72-hour incubation period. We aim to assess the viability of shortening or extending this duration for conducting MPC tests on used hydraulic fluids, thereby potentially enhancing the precision and relevance of MPC tests in hydraulic fluid analysis.

Abstract Varnish layers are optical coatings that act as physico‐chemical barrier between the historical paint layers and the environment. Understanding how varnish materials protect historical paintings over time and in the presence of humidity or organic vapors is of central importance for art preservation. However, probing the behavior of varnish after aging in real conditions remains a challenge. Here the question is addressed by “reshaping” the varnish material from the masterpiece of G. Bellini, the “Transfiguration”, into an optical layer; coupling in situ Ultraviolet‐Visible (UV–vis) and Infrared (IR) ellipsometries, the chemical state is correlated, optical properties and swelling of the varnish in presence of water and organic vapors. It shows that the varnish material aged since the 1950s still exhibits effective water repellence. The methodology may be applied to other relevant historical systems beyond paintings and may help in establishing more efficient preservation strategies for historical artworks.

Particleboards, which are widely used in various fields, are commonly coated with solid and liquid surface coating materials to achieve better physical, mechanical, and aesthetic results. This study produced low-density particleboards from waste wood bark using different adhesive mixtures and densities. These particleboards were then coated with three types of varnish: water-based (Aq), polyurethane-based (Pu), and oil/wax-based (Ow). The color, gloss, and surface roughness values of the coated boards were determined to investigate the effect of varnish type, total adhesive usage, and density on these properties. In the board groups produced with the same glue ratio and density, the roughness values obtained with Ow varnish application were mostly higher compared to Aq and Pu. In the Ow varnish type, the roughness (Rmax) decreased linearly with increasing total adhesive amount in particleboards produced at low density (320 kg/m3). The highest color change (ΔE*) values for all variations were obtained in the Ow varnish type, while the highest gloss values were achieved at 85° and in the B2 (4%-420 kg/m3) board group. It was concluded that higher density should be preferred for smoother and glossier surfaces, which are important in terms of surface properties and aesthetics. Overall, these findings highlight the preference for higher density to achieve smoother and glossier surfaces in areas where surface properties and aesthetics are significant.

This study presents the results of a search for ways to prevent biodestructive processes, occurring in the natural environment of wooden architecture monuments localization. On the Sviyazhsk island since the 16th century an unique site of wooden architecture of the Volga region has been preserved. It is the Trinity Church, the only building, although rebuilt over the centuries, that has survived from the wooden medieval island-town. Climate changes, cultural tourism and living organisms activities make a significant contribution to the change in the initial state of the tree. The greatest contribution to the processes of biodamage is made by mold fungi – micromycetes. Experimental work carried out on a fragmentary sample of a structural element of the Trinity Church revealed that coating the surface of the sample with a synthetic varnish based on a mixture of linear and cyclic methylmethoxypolysiloxanes prevents the growth of microscopic fungi on the surface, among which Aspergillus niger dominates. The growth area of the sample is reduced by about 6 times compared to the untreated variant. By artificial infection of samples with spores of Aspergillus niger, Penicillus chrysogenum, Fusarium graminearum and Aspergillus puulaauensis, the growth area of varnished samples also decreases by 7 times, and the number of conidiophores, reflecting the growth of micromycetes, by 4 times. The obtained results make it possible to recommend the use of polysiloxane coatings for the protection of especially important fragments of wooden artifacts.

Particleboards, which are widely used in various fields, are commonly coated with solid and liquid surface coating materials to achieve better physical, mechanical, and aesthetic results. This study produced lowdensity particleboards from waste wood bark using different adhesive mixtures and densities. These particleboards were then coated with three types of varnish: water-based (Aq), polyurethane-based (Pu), and oil/wax-based (Ow). The color, gloss, and surface roughness values of the coated boards were determined to investigate the effect of varnish type, total adhesive usage, and density on these properties. In the board groups produced with the same glue ratio and density, the roughness values obtained with Ow varnish application were mostly higher compared to Aq and Pu. In the Ow varnish type, the roughness (Rmax) decreased linearly with increasing total adhesive amount in particleboards produced at low density (320 kg/m³). The highest color change (ΔE*) values for all variations were obtained in the Ow varnish type, while the highest gloss values were achieved at 85° and in the B2 (4%-420 kg/m³) board group. It was concluded that higher density should be preferred for smoother and glossier surfaces, which are important in terms of surface properties and aesthetics. Overall, these findings highlight the preference for higher density to achieve smoother and glossier surfaces in areas where surface properties and aesthetics are significant. [ABSTRACT FROM AUTHOR]

Copyright of Wood Industry / Drvna Industrija is the property of Drvna Industrija and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, graphene flakes were obtained using an electrolytic method and characterized using X-ray diffraction (XRD), Raman and FTIR spectroscopy, scanning and transmission electron microscopy (SEM/TEM). Graphene-based composites with varying concentrations of 0.5%, 1% and 3% by weight were prepared with acrylic paint, enamel and varnish matrices. The mechanical properties were evaluated using micro-hardness testing, while wettability and antimicrobial activity against three pathogens (Staphylococcus aureus 33591, Pseudomonas aeruginosa 15442, Candida albicans 10231) were also examined. The results indicate that the addition of graphene flakes significantly enhances both the mechanical and antimicrobial properties of the coatings. [ABSTRACT FROM AUTHOR]

Copyright of Journal of the American Institute for Conservation is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The objective of the study was to analyze the influence of coating treatments on sound propagation speeds in thin boards, along the longitudinal and radial directions of resonance wood. The samples studied were thin boards made of spruce and maple wood with dimensions of 240 mm × 80 mm × 4 mm (length × width × thickness) subjected to different coating treatments (oil-based varnish and alcohol varnish) as well as unvarnished samples, exposed to radiation UV, and specimens treated in the saline fog. The test method consisted of evaluating the propagation speeds of Lamb waves applied to thin plates, according to a semicircular test model, so that the results highlighted both the acoustic response in the longitudinal and radial directions as well as the variation in the anisotropy of the samples with the change in the sound propagation direction relative to wood fibers. Based on the statistical analysis, sound propagation speed profiles were obtained in each of the 38 directions analyzed for all wood samples. The results highlighted that the oil-based varnish led to a decrease in the speed of propagation in the radial direction, compared to the alcoholic varnish, whose major effect was in the longitudinal direction, on the spruce wood. On maple wood, increasing the number of varnish layers, regardless of the type of varnish, led to a decrease in the anisotropy ratio between the longitudinal and radial directions.

Bioactive materials were developed with the ability to release fluoride and provide some antimicrobial potential, to be widely used in dentistry today. However, few scientific studies have evaluated the antimicrobial activity of bioactive surface pre-reacted glass (S-PRG) coatings (PRG Barrier Coat, Shofu, Kyoto, Japan) on periodontopathogenic biofilms. This study evaluated the antibacterial activity of S-PRG fillers on the microbial profile of multispecies subgingival biofilms. A Calgary Biofilm Device (CBD) was used to grow a 33-species biofilm related to periodontitis for 7 days. The S-PRG coating was applied on CBD pins from the test group and photo-activated (PRG Barrier Coat, Shofu), while the control group received no coating. Seven days after treatment, the total bacterial counts, metabolic activity, and microbial profile of the biofilms were observed using a colorimetric assay and DNA–DNA hybridization. Statistical analyses were applied; namely, the Mann–Whitney, Kruskal–Wallis, and Dunn's post hoc tests. The bacterial activity of the test group was reduced by 25.7% compared with that of the control group. A statistically significant reduction was observed for the counts of 15 species: A. naeslundii, A. odontolyticus, V. parvula, C. ochracea, C. sputigena, E. corrodens, C. gracilis, F. nucleatum polymorphum, F. nucleatum vincentii, F. periodonticum, P. intermedia, P. gingivalis, G. morbillorum, S. anginosus, and S. noxia (p ≤ 0.05). The bioactive coating containing S-PRG modified the composition of the subgingival biofilm in vitro, thereby decreasing colonization by pathogens. [ABSTRACT FROM AUTHOR]

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This study presents the current literature regarding the investigation of varnish contamination among the various types of lubricant contaminations. As the duration of use of lubricants increases, the lubricant deteriorates and may become contaminated. Varnish has been known to cause filter plugging, sticking of the hydraulic valves and fuel injection pumps, flow obstruction, clearance reduction, poor heating and cooling performance, and increased friction and wear in various lubrication systems. These problems may also result in mechanical system failures, performance degradation, and increased maintenance and repair costs. To improve the problems caused by varnish contamination, an adequate understanding of varnish is required. Therefore, in this review, the definitions and characteristics, generating machinery, generating mechanisms, causes, measurement methods, and prevention or removal methods of varnish are summarized. Most of the data presented herein are reports from manufacturers related to lubricants and machine maintenance that are included in published works. We expect that this summary will be helpful to those who are engaged in reducing or preventing varnish-related problems. [ABSTRACT FROM AUTHOR]

In this study, specimens from Scots pine (Pinus sylvestris L.), Anatolian chestnut (Castanea sativa Mill.) and Eastern beech (Fagus orientalis Lipsky) tree species, prepared according to ISO 3129, were conditioned according to TS ISO 13061-1. Cellulosic varnish, water-based varnish, and glass polish varnish were applied to their surfaces in accordance with ASTM-D 3023 principles. In the study, roughness (TS 2495 EN ISO 3274 and TS EN ISO 21920-3) and gloss (according to TS EN ISO 2813) values of the samples were calculated after hot and cold check test. Varnished test specimens prepared in 100 mm × 100 mm ×10 mm dimensions were first kept in drying oven at (50±5) °C for 1 hour, then were kept in conditioning room for 1 hour, and then at (-20±2) °C for 1 hour, according to ASTM D1211-97. These processes were accepted as one cycle, and tests were continued until 15 cycles. Afterward, glossiness was measured as perpendicular and parallel to fibers at 60º with a gloss measurement device, and surface roughness values of Ra and Rz were determined with a surface roughness measuring device. According to the results obtained, Scots pine (Pinus sylvestris L.), Eastern beech (Fagus Orientalis Lipsky), and Anatolian chestnut (Castanea sativa Mill.) varnish-coated wood material surfaces all showed a decrease in gloss values after hot-cold shock effect. While an increase occurred in Rz values of roughness for all wooden surfaces, Ra values roughness increased for Scots pine and chestnut and decreased for eastern beech. Gloss and roughness values of surface-treated wood materials against changing weather conditions can determine usefulness of the surface material used. The findings obtained in this study can be useful to manufacturers who use wooden products in the design of marine vehicles and those who export furniture to countries in different climatic conditions.

The purpose of this study was to predict the adhesion strength of the varnish, which is applied as a protective coating/finish on the surface of wooden material using soft computing models. In this study, the soft computing approaches were applied to oak (Quercus Petrea L.), chestnut (Castanea sativa M.), and scotch pine (Pinus sylvestris L.) with water-based, polyurethane, and acrylic varnishes. The adhesion strength of the varnish was determined in accordance with the Turkish Standard Institute-24624 and ASTM D4541. The outcome of the experiment was used to develop artificial neural network (ANN) and fuzzy logic (FL) prediction models. The total number of 360 data points was split as 80 % of training and 20 % of test for the model development. During the application of the ANN, 6 features were used as an input, while the adhesion strength was used as an output of the model. The coefficient of determination values (R2) for training and testing in the ANN models were 0.9939 and 0.9580, respectively. In the case of the ANFIS model, R2 values for training and testing were 0.9917 and 0.9929, respectively. Considering the MAPE, RMSE, and R2 values obtained from the results of both training and test values, it can be concluded that the ANFIS model showed a more successful performance in estimating varnish adhesion strength. Therefore, ANN and ANFIS have the potential to provide time and cost-efficient benefits in estimating wood adhesion strength.

Doğal ve organik bir yapıya sahip olan ağaç malzeme her ne kadar dış etkilere karşı kendisini koruyacak birtakım özelliklere sahip olsa da harici etkilere karşı uzun süre dayanamaz. Bu nedenle ya emprenye edilmekte ya da yüzeyleri koruyucu katmanla (boya/vernik) kaplanmaktadır. Ağaç malzeme yüzeylerine uygulanan bu koruyucu katmanlar, zamanla koruyucu özelliğini yitirebilmekte, malzemenin dayanımını, kullanım ömrünü azaltmakta ve estetik olarak kötü görüntüye neden olabilmektedir. Bu yüzden, eskimiş koruyucu katmanların ahşap yüzeylerinden kaldırılarak gerekli bakımların yapılması ve yeniden koruyucu katman uygulanması gerekmektedir. Koruyucu katmanların ağaç malzeme yüzeyine ve çevreye zarar vermeden temizlenmesi oldukça zor ve zahmetli bir işlem olmakla birlikte, günümüzde kullanılan birçok yöntem ve temizleme gereci bulunmaktadır. Bu çalışmada, ağaç malzeme yüzeylerindeki koruyucu katmanların temizliğinde sıkça tercih edilen çevreye duyarlı yöntem ve temizleme medyaları ele alınmıştır. Bu çalışmanın temel amacı, ahşap yüzey temizliği alanındaki araştırmalar ile elde edilen bilgi ve tecrübeleri topluma tek kaynak üzerinden aktarmak ve böylece araştırmacı ve uygulayıcıların literatüre ulaşmasını kolaylaştırmaktır.

Among the several ways used in wastewater treatment, the photocatalysis process is a more novel and alternative process that is increasingly employed in recent years. This work aims to improve the performance of the photocatalyst process by using air bubbles in removing the BTEX from produced water as an indicator of process efficiency. The study also shows the effect of influencing factors (pH and residence time) on the photocatalysis process. The study was done in a rectangular column with dimensions of 200 mm width, 30 mm depth, and 1500 mm height. Commercial titanium oxide (TiO2) coated on a plate by the varnish was used as a source of the photocatalyst. The experiment was carried out under different values of gas flow rate (0-3 L/min) to evaluate its effect on the photocatalyst process, the effect of other variables of pH (3-11), and irradiation time (30-120) min was also studied. A new method of the coating was adopted by using an alumina plate with varnish as an adhesive. The characteristics results show that the coated plate has hydrophilic properties and that there is no significant change in the crystal structure of the TiO2 nanoparticles and the varnish before and after 60 h of the photocatalytic process, indicating that the plate is still effective after 60 h usage under different conditions. The results also show that the introduction of air bubbles enhances the removal efficiency of BTEX significantly and the best removal effectiveness of BTEX was 93% when pH = 5 after 90 min and 90% when pH = 3 after 120 min. The removal rate also reached 86% when pH = 7 after 120 min all at a flow rate of 3 L/min. The percentage of removal decreased at pH = 9 and 11, reaching 64% and 50%, respectively after 120 min and a flow rate of 3 L/min. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: The oral cavity and the teeth are frequently subjected to numerous physiological pH variations, mainly due to the type of diet. These changes are the main cause of enamel demineralization and consequent breakage under mechanical forces. This causes severe sensitivity and sometimes pain, which endures unless the hard tissue is remineralized. Since enamel does not self-repair, the application of alloplastic materials that have the property of releasing remineralizing ions is strongly recommended. The aim of this in vitro study is to evaluate the effectiveness of two different toothpastes and a fluoride varnish in the prevention of demineralization, and their ability to remineralize enamel after it has undergone several acidifications. Methods: Eight human teeth with no caries or defects were prepared. The acid attack simulations were performed using a commercial cola carbonated drink. Samples were immersed in 5 mL of soft drink for two minutes at room temperature, and then were rinsed with distilled/deionized water. The immersion process lasted about 2 min, and was repeated four times for a total of eight minutes. Then, two different types of toothpaste, one with and one without fluoride, and a fluoride varnish were applied to the surfaces of the samples and rinsed off with demineralized water. A second acidification cycle was then carried out, with the subsequent reapplication of the three different products to evaluate their ability to protect against demineralization. SEM and profilometer analysis were then carried out to evaluate the results. Results: The statistical analysis showed a good remineralization capacity for all three products, especially in the fluoride-varnish-treated samples. However, regarding protection from demineralization, non-fluoride toothpaste was found to be ineffective, while fluoride toothpaste and varnish produced positive results. Conclusions: Dental professionals should advise fluoride toothpastes and varnishes over non-fluoride toothpastes. Fluoride toothpastes and varnishes represent a valid treatment for surface remineralization after a first acid attack and for protection from subsequent demineralization in an acid environment, such as that which can develop in the oral cavity. [ABSTRACT FROM AUTHOR]

Abstract Murujuga in Western Australia has the largest concentration of ancient rock engravings (petroglyphs) in the world. However, the Murujuga rock art is potentially threatened by local industrial air pollution, in particular by acid rain, but unambiguous scientific evidence is still missing. Here, we report on results of an accelerated weathering experiment, simulating Murujuga weather and climate conditions that was designed and performed to test whether the expected small changes in chemical, mineralogical, and physical characteristics of the rock surface can be detected and reliably quantified by various analytical means. Locally acquired Murujuga granophyre and gabbro samples with natural varnish were artificially weathered for up to four months in a climate chamber under conditions that simulated 2 years of natural weathering. Mineralogical, chemical, and physical changes were qualitatively monitored by X-ray diffraction and confocal Raman spectroscopy, and quantified by colorimetry, portable X-ray fluorescence spectrometry, and micro-computed tomography. In addition, artificial rainwater that was sprinkled over the rock samples was collected and analysed by inductively-coupled plasma mass spectrometry. The results show significant chemical and physical changes of the surfaces of the rock varnish after 1 month of artificial weathering. The analytical results demonstrate that it is possible to quantitatively monitor small changes caused by the weathering of gabbro and granophyre. Therefore, such a semi-actualistic experimental approach, when carefully designed, potentially allows testing the hypothesis that the weathering rate of the Murujuga petroglyphs is increased by local industrial air pollution. Further experimental work is currently under way.

Background: Patients with multi‐bracketed fixed orthodontic appliances are at a higher risk of developing enamel demineralisation. Aim: To compare the efficacy of the quarterly application of two varnishes in preventing white spot lesions (WSLs) during multi‐bracketed fixed orthodontic treatment. Design: Ninety‐nine patients were randomly allocated into three intervention groups: Group A—standard oral hygiene instructions (OHI); Group B—5% sodium fluoride (NaF) varnish with standard OHI; and Group C—NaF plus tricalcium phosphate varnish with standard OHI. The outcome was assessed at 6‐monthly intervals using a quantitative laser fluorescence device, clinical evaluation and photographic evaluation on six maxillary anterior teeth. A logistic regression model using generalised estimating equations with the intervention group, time and their interaction was used to compare the occurrence of WSLs, whereas the independent‐samples Kruskal–Wallis test was used to compare the means of fluorescent values among different groups at p =.05. Results: Generalised estimating equations (with intervention and time as predictors) showed that only the effect of time was found to be significant (p <.001), whereas there was no significant difference among the three intervention groups (p =.305) using clinical assessment or photographic assessment (p =.599). At the 18‐month follow‐up, sodium fluoride (NaF) varnish with standard OHI was shown to reduce the odds of WSLs by 55% (p =.200), and NaF plus tricalcium phosphate varnish with standard OHI by 42% (p =.327). Conclusion: The study failed to demonstrate that the quarterly application of both the study varnishes with OHI provided additional benefits compared with standard OHI alone in preventing WSLs, taking the effect of time of follow‐up into consideration. There were higher odds of developing WSLs with an increased duration of orthodontic treatment. [ABSTRACT FROM AUTHOR]

The synthesis of novel phosphorus-containing telomers (P-telomers) was conducted via a solution-free UV-initiated telomerization process of butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, and styrene, different phosphorus telogens (dimethyl phosphite (DMPh), dibutyl phosphite (DBPh), diphenyl phosphite (DPPh) or dibutyl phosphate (DBP)), and a radical photoinitiator-acylphosphine oxide (APO). The course of the UV-phototelomerization process was monitored by photo-DSC and the chemical structures of telomers were assessed by FTIR. Final UV-photocurable varnish compositions consisted of prepared P-telomer syrups, crosslinking monomer (pentaerythritol triacrylate; PETIA), and a radical UV-photoinitiator (α-hydroxyalkylphenone, HAP). The influence of P- telomers on the optical and mechanical features of coatings was investigated. Relatively the highest hardness and satisfactory scratch values, as well as water and solvent resistance, were observed for varnish based on DMPh-telomers. While the strongest adhesive bond to a glass substrate was reported for DPPh-telomers. It is worth pointing out that the P-telomers did not affect the gloss values of varnishes in comparison to the telomer-free reference sample. [ABSTRACT FROM AUTHOR]

This paper presents the results of a series of tests – using a recently-published set of methodological guidelines referred to here as the Protocol – on varnishes traditionally used in the protection and enhancement of graphic artworks. The aim of the research was to study the characteristics of different varnishes when they are applied to a graphic artwork and to analyze their behavior when exposed to conditions that cause alterations, be these natural factors, accidental, or the result of a conservation intervention. Lastly, the study sought to determine whether each varnish was suitable for conservation purposes. Five varnishes were selected for the study: egg white, gum arabic, shellac, rosin, and dammar. Paper test samples were used to study the characteristics of the recently applied varnishes: dimensions, weight, thickness, color, brightness/gloss, pH, surface appearance, drying time, degree of absorption by the substrate, and adhesion to the substrate. The behavior of varnishes was studied via a series of tests that recreated adverse conditions (humidity, light, and temperature). These tested for resistance to ambient humidity, immersion in water, dry-heat aging, and aging in a climate test chamber. After applying the Protocol it was concluded that the varnishes most resistant to different alteration factors are gum arabic and dammar resin. By contrast, shellac and rosin are the most susceptible to alterations, which precludes their use as a conservation material. As well as indicating the varnishes that present the minimum interaction with the substrate and the greatest long-term durability, the results of this research also provide a useful guide to the behavior of these varnishes for their use in preventive conservation. [ABSTRACT FROM AUTHOR]

Currently, there are several types of electric machines in which brush-contact devices (BCD), consisting of electric brushes and slip rings (collectors), are used to transfer electric current from the stationary part to the rotary one. These include synchronous and asynchronous motors with a phase rotor, DC and AC collector machines, as well as turbine generator. As the experience of operating these machines shows, the largest share of their failures occurs due to the BCD-related breakdowns, making up 25% of total annual breakdowns. Officially, according to the data of Russian Scientific Research Institute on Electrical Engineering, out of the 250 200 – 800 MW turbine generators operating in the Russian Federation, 20% of their failure and up to 20% of their idle time for repair involve BCD defects. The turbine generator BCD is a structural unit that requires constant supervision and adjustment during the turbine generator operation. Inadequate monitoring can lead to the rapid development of "flashover"—a severe accident, followed by a long downtime for the equipment repair. Therefore, there is a need to improve the reliability of the BCD unit operation. The following objectives have been accomplished in this paper: physical processes during the turbine generator BCD operation are considered; the main types of BCD failures are analysed; current global methods for detecting excessive vibration and defects in the turbine generator BCDs are examined; methods of predicting the development of defects by means of statistical mathematical simulation of the objects have been proposed. [ABSTRACT FROM AUTHOR]

This paper is dedicated to characterizing the steady-state and dynamic behavior of journal bearings with the provision for varnishing. Degraded base oils and additives cause varnish at high temperatures. Once the varnishing initiates, the oil flow is restricted due to the reduction in film thickness, which leads to an increase in the operating temperature and further accelerated varnishing. The effect of the varnish on the bearing performances is predicted by solving the Reynolds equation for the pressure distributions with the mass conservation algorithm coupled with the energy equation through the viscosity. The solution of the Reynolds equation with the perturbations of the displacement and the velocity is used to calculate the stiffness and damping coefficients and determine the dynamic behavior of the bearing. At a given eccentricity ratio, the maximum pressure and temperature with the varnish become considerably higher than those without the varnish due to the reduced film thickness. Results are presented for both single and double axially grooved journal bearings. Results show that the maximum pressure decreases when the varnish size extends circumferentially at a given varnish thickness, but the maximum temperature still remains relatively constant. For both single and double-grooved bearings, the critical speed decreases considerably, leading to the reduction of the stability of the system. [ABSTRACT FROM AUTHOR]

In this study, graphene flakes were obtained using an electrolytic method and characterized using X-ray diffraction (XRD), Raman and FTIR spectroscopy, scanning and transmission electron microscopy (SEM/TEM). Graphene-based composites with varying concentrations of 0.5%, 1% and 3% by weight were prepared with acrylic paint, enamel and varnish matrices. The mechanical properties were evaluated using micro-hardness testing, while wettability and antimicrobial activity against three pathogens (Staphylococcus aureus 33591, Pseudomonas aeruginosa 15442, Candida albicans 10231) were also examined. The results indicate that the addition of graphene flakes significantly enhances both the mechanical and antimicrobial properties of the coatings.

Introduction: Dentin hypersensitivity (DH) is one of the most common problems, but to date, no single agent or form of treatment has been found effective. Lasers have promising potential for the treatment of DH. This in vitro study aims to compare and evaluate the desensitising ability of a combination of sodium fluoride varnish (NaF) and Erbium: yttrium-aluminium-garnet (Er: YAG) laser by assessing tubule occlusion and depth of penetration of the agent in dentinal tubules through Scanning electron microscope (SEM) and Confocal laser scanning microscope (CLSM), respectively. Materials and Methods: Forty-five extracted maxillary premolar teeth were included in this study. A 3-mm-thick horizontal slice was prepared from the cementoenamel junction of each tooth. Each slice was transversely separated into two halves as buccal and lingual samples. Ninety samples were obtained, and these samples were randomly divided into six equal groups. Groups A, B, C, and D were used for the evaluation of tubule occlusion with SEM Groups E and F were evaluated for dentin permeability with CLSM. Results: Intergroup comparisons showed statistically significant differences among groups, and it was observed that the combined use of Sodium fluoride and Er: YAG Laser showed better occluding (Group D) and depth penetration (Group F) effect when analysed using SEM and CLSM, respectively. Conclusion: It can be concluded that a combination of fluoride varnish and lasers offers a significant role in dentinal hypersensitivity.

Copyright of Duzce University Journal of Science & Technology is the property of Duzce University Journal of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Among the several ways used in wastewater treatment, the photocatalysis process is a more novel and alternative process that is increasingly employed in recent years. This work aims to improve the performance of the photocatalyst process by using air bubbles in removing the BTEX from produced water as an indicator of process efficiency. The study also shows the effect of influencing factors (pH and residence time) on the photocatalysis process. The study was done in a rectangular column with dimensions of 200 mm width, 30 mm depth, and 1500 mm height. Commercial titanium oxide (TiO2) coated on a plate by the varnish was used as a source of the photocatalyst. The experiment was carried out under different values of gas flow rate (0-3 L/min) to evaluate its effect on the photocatalyst process, the effect of other variables of pH (3-11), and irradiation time (30-120) min was also studied. A new method of the coating was adopted by using an alumina plate with varnish as an adhesive. The characteristics results show that the coated plate has hydrophilic properties and that there is no significant change in the crystal structure of the TiO2 nanoparticles and the varnish before and after 60 h of the photocatalytic process, indicating that the plate is still effective after 60 h usage under different conditions. The results also show that the introduction of air bubbles enhances the removal efficiency of BTEX significantly and the best removal effectiveness of BTEX was 93% when pH = 5 after 90 min and 90% when pH = 3 after 120 min. The removal rate also reached 86% when pH = 7 after 120 min all at a flow rate of 3 L/min. The percentage of removal decreased at pH = 9 and 11, reaching 64% and 50%, respectively after 120 min and a flow rate of 3 L/min. [ABSTRACT FROM AUTHOR]