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Introduction: Microleakage is an important property that has been used in assessing the success of any restorative material used in restoring a tooth. Immediate application of a surface coating agent is suggested to protect glass ionomer cement against moisture contamination and dehydration during early setting. Aim: To compare marginal microleakage of two different Glass Ionomer Cement (GIC)- Conventional GIC and Resin Modified GIC in primary anterior teeth using three surface coating materials. Materials and Methods: An in vitro study was conducted between January 2014 to October 2017 on freshly extracted 40 anterior primary teeth which were randomly assigned into two main groups (Fuji II GIC and Fuji II LC GIC) with four subgroups (control-no surface coating, A=GC Fují Varnish II, B=GC G-Coat Plus, C=Icon). A standardised Class V cavity preparation was prepared on the labial surface of each tooth. Specimens were coated with two layers of nail varnish, leaving a 1 mm window around the cavity margins and placed in a solution of Methylene blue Dye for 24 hour at 37°C. The teeth were sectioned longitudinally in a buccolingual direction of the restorations and evaluated under stereomicroscope to check extent of dye penetration. The results were analysed by ANOVA and Tukey’s post-hoc test (p≤0.05). Results: It was found that maximum microleakage was seen in group 1 (Fuji II GIC) as compared to group 2 (Fuji II LC GIC) and it was non-significant (p=0.53). Ascending order for mean microleakage for Group 1 was as follows: Control >GC Fuji Varnish >Icon DMG >GC G-Coat and for Group 2: Control >GC Fuji Varnish >Icon DMG >GC G-Coat. Icon when compared with Gc coat and Varnish also showed non-significant (p=0.137) difference in Group 2. Conclusion: All three different surface coatings can seal glass ionomer restorations. The GC G-Coat Plus has the least microleakage on Resin-Modified GIC (RMGIC) compared to the other surface coatings. This would aid the clinicians to make appropriate decision regarding the choice of material to be used for restoration and coating in anterior primary teeth.

In this paper, a novel approach for the simulation of cavitation and aeration in hydraulic systems using the lumped parameter method is presented. The presented approach called the Hybrid Rayleigh–Plesset Equation model is derived from the Rayleigh–Plesset Equation representative of bubble dynamics and overcomes several shortcomings present in existing lumped parameter based cavitation modeling approaches. Models based on static approximations do not consider the non-equilibrium effects of phase change on the system and incorrectly predict the system dynamics. On the other hand, the existing dynamic cavitation modeling strategies account for the non-equilibrium effects of phase change but express the evolution of phases through approximations of the Rayleigh–Plesset Equation (such as exclusion of nonlinear interactions in bubble dynamics), which often lead to physically unrealistic time-scales of bubble growth or dissolution. This paper presents a dynamic model for cavitation which is capable of predicting cavitation in hydraulic systems while preserving the nonlinear dynamics arising from the Rayleigh–Plesset Equation. The derived model determines the evolution of phases in terms of physically realizable parameters such as the bubble radius and the nuclei density, which can be estimated or determined experimentally. The paper demonstrates the effectiveness of the derived modeling approach with the help of numerical simulations of an External Gear Machine. Results from the simulations employing the proposed model are compared with an existing dynamic cavitation modeling approach and validated with experimental results over a range of dynamic parameters.

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An a priori analysis of subfilter-scale (SFS) species structure important to estimate chemical reaction rates in large-eddy simulation (LES) is performed using direct numerical simulation (DNS) of a turbulent premixed flame at a turbulence Reynolds number Re0=329 and Karlovitz number Ka0=7.23 with semi-detailed finite-rate chemistry. Differences between the complete chemical reaction rates extracted from DNS and those estimated from LES-filtered variables are quantified. The spatial distributions of these differences are found to be localized in regions surrounding the flame front for representative reactions. Within these regions, variations in the localization relative to the flame, scale, and magnitude of the SFS species concentrations are quantified, and mean SFS structure is determined. SFS species structure is found in two groupings: “single-banded” structure characterized by one distinct peak and “double-banded” structure characterized by two peaks of opposite signs. Species that are produced and consumed within the flame such as CH2O and HCO are observed to have single-banded structure, and species displaying a frontal behavior such as n-C7H16 and OH are found to have double-banded structure, on average. The local SFS structure surrounding the flame is impacted by neighboring flame-flame interactions as well as by variations in flame curvature. The impacts of the flame-flame interactions are strong when the SFS species structure has “large” length scales with concentration peaks significantly displaced from the flame front. Curvature effects are shown to be strong in high curvature regions of the flame.