Structural and thermodynamic properties for the BaMn(Fe=V)F7 Fluoride glass system by using the Hybrid Reverse Monte Carlo simulation

The Hybrid Reverse Monte Carlo (HRMC) simulation has been widely used as a very useful method for displaying the pair partial distribution functions (PDFs) g(r) eliminating as soon as possible the artificial satellite peaks appear by the RMC simulation. The HRMC is an extension of the RMC algorithm, which introduces an energy penalty term (potential) in the acceptance criteria.The glass retains the structure presented by the liquid at the glass transition temperature Tg, and the thermodynamic properties are influenced by these structural modifications. We are interested in this study to apply the structural parameters g(r), obtained from HRMC simulation, to determine some structural and thermodynamic properties for the BaMn(Fe=V)F7 Fluoride glass.The calculated structural properties such as the running coordination number n(r) were in good agreement with coordination constraint. We suggest also that the structural parameters g(r) is a good tool to determine the thermodynamic properties as the energy of the system.

Incorporation of Hydroxyapatite into Glass Ionomer Cement (GIC) Formulated Based on Alumino-Silicate-Fluoride Glass Ceramics from Waste Materials

Glass ionomer cement (GIC) is a well-known restorative material applied in dentistry. The present work aims to study the effect of hydroxyapatite (HA) addition into GIC based on physical, mechanical and structural properties. The utilization of waste materials namely clam shell (CS) and soda lime silica (SLS) glass as replacements for the respective CaO and SiO2 sources in the fabrication of alumino-silicate-fluoride (ASF) glass ceramics powder. GIC was formulated based on ASF glass ceramics, polyacrylic acid (PAA) and deionized water, while 1 wt.% of HA powder was added to enhance the properties of the cement samples. The cement samples were subjected to four different ageing times before being analyzed. In this study, the addition of HA caused an increment in density and compressive strength results along with ageing time. Besides, X-ray Diffraction (XRD) revealed the formation of fluorohydroxyapatite (FHA) phase in HA-added GIC samples and it was confirmed by Fourier Transform Infrared (FTIR) analysis which detected OH‒F vibration mode. In addition, needle-like and agglomeration of spherical shapes owned by apatite crystals were observed from Field Emission Scanning Electron Microscopy (FESEM). Based on Energy Dispersive X-ray (EDX) analysis, the detection of chemical elements in the cement samples were originated from chemical compounds used in the preparation of glass ceramics powder and also the polyacid utilized in initiating the reaction of GIC.

Conventional doped silica/fluoride glass fibers for low loss and minimum dispersion effects

<p><span>This paper has clarified the conventional silica doped (SiGeO2) and aluminum fluoride (AlF3) fibers for low loss and minimum dispersion effects for upgrading fiber-optic communication systems. The total dispersion with the total losses are modeled for both fibers. Fiber bandwidth and the power received are estimated based on different dopant ratios. The spectral and thermal effects are applied on both fibers. The study assured the negative effects of increasing ambient temperatures and the positive effects of increasing dopant ratios on the performance of the fibers. </span></p>

Effect of the polishing procedure and surface sealant application on fluoride release

Objective: This study aimed to assess the effect of the polishing procedure and surface sealant application on the fluoride release of restorative materials. Material and Methods: The groups were consisted of using five different restorative materials were employed: Beautifil II, GCP Glass Fill, Amalgomer CR, Zirconomer and Fuji IX GP. 30 disk-shaped specimens (8x2 mm) were prepared from each material. Each group was subdivided into three groups considering finishing procedures: Mylar strip, polishing with Super-Snap discs, G-Coat Plus application after polishing with Super-Snap discs. The amount of fluoride released into distilled water was measured using a fluoride ion-selective electrode and ion analyzer after 24 hours, followed by measurement on days 3, 7, 15, 21, and 28. Surface analysis of the materials was performed with SEM (Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy). The data were statistically analyzed using two-way repeated measure ANOVA and LSD test (p=0.05). Results: The highest amount of fluoride released was measured after the first 24 h for all materials. Beautifil II released less fluoride than other materials in all measurement periods (p<0.05). After polishing, the amount of fluoride released from all materials except Beautifil II increased (p<0.05). The application of G-Coat Plus did not impact the amount of fluoride release of any materials (p>0.05). EDS analysis showed the most percentage of oxygen in all materials. Conclusion: The polishing procedure might induce an increase in fluoride release of glass ionomer-based materials, and the application of G-Coat Plus cannot affect the amount of fluoride release. Keywords Energy dispersive x-ray spectroscopy; Fluoride; Glass ionomer cement.