Non-Metallic Material Science

Investigation of Dielectric Properties of Quaternary Ceramic 0.47BNT-0.04BT-0.37PMN-0.18PT

2024-03-06T09:08:12+08:00

Dielectric dispersion analysis has been carried out for the first time on a new quaternary ceramic [0.47(Bi0.5Na0.5)TiO3-0.04BaTiO3-0.31Pb(Mg1/3Nb2/3)O3-0.18PbTiO3] having a morphotropic phase boundary composition. The measurement of the dielectric parameters has been carried out in the frequency range of 200 Hz to 2 MHz and temperature range from 30 ^oC to 300 ^oC. The material showed high dielectric constant, low dielectric loss, negligible DC conductivity and high ferroelectric to paraelectric transition temperature. A clear Debye type relaxation was observed in the dielectric constant and dielectric loss data. An interesting feature of two Debye peaks has been noticed in dielectric loss versus frequency curves in the temperature range 125 ^oC to 175 ^oC. These peaks shift towards higher frequencies when temperature is increased. The extracted relaxation times of the two peaks are three orders of magnitude different and have been found to follow the Arrhenius law with significantly different activation energies.

Weathering of Wood and Rocks and the Role of Coating in Protection

2023-12-26T09:03:17+08:00

This article explores the effect of weathering on the degradation of wood and rocks and discusses its prevention strategies and safety aspects. Weathering, including natural, enhanced, accelerated, silicates, polymer degradation and erosion is discussed in this article. Rocks weather naturally very slowly and gradually. Minerals weathering and silica-rich layer formation during single-stage and two-stage carbonation like serpentinization of rocks are discussed. A substantial amount of work has been performed for polymeric coatings globally to extend the life of coating surfaces. The ideal coating system would combine the advantages of performance offered by solvent-based coatings with the advantages offered by water-based coatings in the areas of environmental protection, health and safety. Weathering prevention will stop the wastage of materials.

Antibacterial Potential of Pulp Capping Materials

2024-01-12T10:21:56+08:00

A critical analysis of the antibacterial effect of the main representatives of calcium silicate cements (CSCs) was made. An analysis of the most frequently used methods for screening the antibacterial activity of materials has been made. The inhibitory activity of CSCs against major types of microorganisms such as Candia albicans, E. faecalis, and strains streptococcus was evaluated and compared. The antibacterial effects of CSCs are not yet well and completely known because no evidence compares the antibacterial properties of bioceramic materials with a uniform methodological approach. It is important to provide standardization of testing methods for evaluating the antibacterial potential of the materials and different bacterial strains. To this stage, there are no reproducible and standardized methods for evaluating of antibacterial activity of CSCs.