Search

A simple and efficient approach for the S‐arylation of tetrazole‐5‐thiol using copper oxide nanoparticles has been developed. Recently, heterocyclic thiols have attracted a great deal of interest due to their diverse biological and pharmacological properties. Thus, great efforts have been devoted in introducing efficient protocols for the synthesis of such compounds. The utilization of copper oxide nanoparticles has been substantially chosen for catalysis due to their low cost, high surface area, sustainability, and reusability. The distinctive features of this methodology involve a ligand‐free catalytic system, simple reaction procedure, shorter reaction time, wide substrate scope compatibility, and high yield of the products. [ABSTRACT FROM AUTHOR]

Electrical properties of ceramic materials has become an area of increasing interest in research because these materials possess a great potential for solid-state devices. Conducting polymer composites have attracted considerable interest in recent years because of their numerous applications in a variety of electric and electronic devices. It has been observed that these materials possess a very high relative dielectric constant and high electrical properties at room temperature. Such a high dielectric constant is one of the important parameters in capacitor fabrication and a high electrical conductivity can be used for ionic batteries and electrochemical sensors. [ABSTRACT FROM AUTHOR]

The bactericidal action of silver nanoparticles has been observed by many researchers since few years. In this study, we have developed an antibacterial ceramics (ACs) by absorbing synthesized silver nanoparticles within the ceramic matrix developed by us from an abundantly available coal fly ash, an extremely hazardous by-product of thermal power plants. Nanoparticles dispersions of different particle sizes were made absorbed in to the ceramic matrix to evaluate its bactericidal activity against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria, taken as the model microorganisms. This study showed that the total bactericidal action of ACs depends on the size of absorbed nanoparticles and the content of nanoparticles in the dispersions within the ceramic matrix. ACs thus developed release very slowly a minute amount of nanoparticles and show strong and prolonged bactericidal activity against pathogenic strain of both types of bacteria. The concentration of prepared nanoparticles in dispersion and the concentration of released nanoparticles in aqueous medium from the absorbed ceramic matrix were measured using inductively coupled plasma spectrophotometer. The mechanism of the antibacterial action was also studied using transmission electron microscopy image analysis of the bacterial cross-section of both types of bacteria. [ABSTRACT FROM AUTHOR]

Nowadays the increased generation of fly ash from thermal power plants is a major concern to our society due to its harmful impact on environment. To utilize this waste in a useful way, we have developed a novel ceramic material which was produced by treating fly ash with bauxite during sintering process. The developed ceramic material acquired increased hardness because of enhanced mullite content during the process with an additional property of reducing pathogenic bacterial growth by more than 90%. The mechanism of their antibacterial action was studied by TEM image analysis of the bacterial cross section. Mullite content and the crystallinity of mullite have increased with increasing concentration of bauxite during sintering process. A maximum of ~ 31% increase in mullite phase was obtained for 50% w/w bauxite and thus increased the hardness which was measured by LEICA Vickers hardness tester. The structural composition of the developed ceramics materials and the surface texture were evaluated by FTIR studies and FESEM micrographs, respectively. This work highlights a sustainable approach of using fly ash in developing antimicrobial ceramics in an eco-friendly way having a vast potential to be used in the bacteria prone area like hospitals. [ABSTRACT FROM AUTHOR]

Quartz is widely replaced by fly ash in traditional porcelain composite. Increased strength and stability of the fly ash-mixed composite depends on the quantity and crystallinity of the mullite phase in the fly ash. Our aim in this investigation is to increase the formation of mullite in nanocrystalline form and study the effect of temperature. Quantitative estimation of mullite and residual quartz content were done by X-ray diffraction (XRD) and nanostructure and crystallization were studied using differential thermal analysis (DTA), field effect scanning electron microscopy (FESEM), XRD and Fourier transform infrared (FTIR) spectroscopy. The results show that fly ash sieved through 250 holes/cm mesh contain more mullite initially and growth of mullite as well as glass formation was faster in this sample compared to coarse fly ash. The maximum mullite in these samples was formed at 1600°C. Transformation of quartz and cristobalite phases into glassy phase was also faster for smaller particle sizes of fly ash. [ABSTRACT FROM AUTHOR]