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Aim To assess the antimicrobial activity of herbal, homeopathic, and conventional dentifrices against oral microorganisms. Methodology Mueller Hilton agar was used to cultivate distinct strains of Streptococcus mutans and Enterococcus faecalis, whereas Candida albicans was cultured on a potato dextrose agar medium. Diffusion ratios of 1:5, 1:10, and 1:15 were obtained by diluting 1 gram of each dentifrice (KP Namboodiri, Homeodent, and Colgate Strong Teeth) in 4 ml, 9 ml, and 14 ml of distilled water, respectively. The culture medium was filled with sterile discs. Twenty µl of each dilution of prepared dentifrice formulations were incorporated using a micropipette. The agar plates were incubated for 24 hours at 37ºC. Result The findings indicate that there was a higher zone of inhibition against Streptococcus mutans with herbal dentifrice at 10 mm, 8 mm, and 6.5 mm, followed by conventional dentifrice at 10 mm, 7.5 mm, and 7 mm, and the lowest with homeopathic dentifrice at 8 mm, 7 mm, and 7 mm at 1:5, 1:10 and 1:15 dilutions, respectively. Conventional dentifrice was found to inhibit Enterococcus faecalis at 9 mm, 8 mm, and 7 mm with 1:5, 1:10, and 1:15 dilutions followed by herbal dentifrice at 9 mm, 7 mm with 1:5, 1:10 dilutions, and no inhibition at 1:15 dilution. In contrast, homeopathic dentifrice displayed no inhibition at 1:5, 1:10, and 1:15 dilutions. Neither homeopathic nor conventional dentifrices inhibited Candida albicans, but herbal dentifrices showed a 10 mm zone of inhibition at 1:10 dilution. Conclusion Conventional and herbal dentifrices were found to be more effective against Streptococcus mutans than the homeopathic dentifrice used in the study, whereas herbal dentifrice was more effective against Candida albicans when compared to conventional and homeopathic dentifrices.
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Magnesium alloys are extensively used for weight reduction in automotive and aircraft applications. This research presents the effect of heat and cryogenic treatment on aluminium-zinc-based Mg alloys. Both treatments can improve the mechanical and corrosion properties of the AZ series Mg alloy. The review deals with a broad understanding of the microstructure changes that occur during heat and cryogenic treatment of Mg alloy. The mechanical and corrosion characteristics of heat and cryogenic treated AZ31, AZ91, AZ63, and AZ80 Mg alloys are discussed. The essential strengthening mechanisms of heat and cryogenic treated AZ series Mg are discussed with microstructure changes. This review has also shown a few gaps in research on the selection of suitable pre- and post-treatment processes for Mg alloy. The effects on grain refinement and the formation of secondary phase particles are discussed in detail. The related crystallographic plane, twining, and dislocation changes are out of the scope of this review. Finally, the correlations of the above changes to mechanical properties are the directions of the future.
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Cutting tool characterization plays a crucial role in understanding the behavior of machining operations. The selection of a suitable cutting material, the operating conditions for the work piece, is necessary to yield good cutting-tool life. Several pieces of research have been carried out in cutting-tool characteristics for turning operation. Only a few pieces of research have focused on correlating the vibrations and stress with wear characteristics. This research article deals with stress induced in silicon carbide tool inserts and coated tool inserts while machining SS304 steel. Since this material is much less resistant to corrosion and oxidation it is widely used in engineering applications such as cryogenics, the food industry and liquid contact surfaces. Moreover, these materials have much lower magnetic permeability so they are used as nonmagnetic engineering components which are very hard. This article focuses on the machining of SS304 by carbide tool inserts and then, the cutting forces were observed with a tool dynamometer. Using observed cutting forces, the induced stress in the lathe tool insert was determined by FEA investigation. This research also formulates an idea to predict the tool wear due to vibration. Apparently, the worn-out tool vibrates more than new tools. Using the results, the relation between stress, strain and feed rate, depth of cut and speed was found and mathematically modeled using MINI TAB. It was observed that carbide tool inserts with coating withstand better than uncoated tools while machining SS304. The results were anticipated and correlation between the machining parameters furnished the prediction of tool life and obtaining the best machining outcomes by using coated tool inserts.
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The advancement of 3D-printing technology has ushered in a new era in the production of machine components, building materials, prototypes, and so on. In 3D-printing techniques, the infill reduces the amount of material used, thereby reducing the printing time and sustaining the aesthetics of the products. Infill patterns play a significant role in the property of the material. In this research, the mechanical properties of specimens are investigated for gyroid, rhombile, circular, truncated octahedron, and honeycomb infill structures (hexagonal). Additionally, the tensile properties of PLA 3D-printed objects concerning their infill pattern are demonstrated. The specimens were prepared with various infill patterns to determine the tensile properties. The fracture of the specimen was simulated and the maximum yield strengths for different infill structures and infill densities were determined. The results show the hexagonal pattern of infill holds remarkable mechanical properties compared with the other infill structures. Through the variation of infill density, the desired tensile strength of PLA can be obtained based on the applications and the optimal weight of the printed parts.
