ESTIMATED DAILY INTAKE AND EXPOSURE OF SODIUM BENZOATE AND POTASSIUM SORBATE THROUGH FOOD PRODUCTS IN SCHOOL CHILDREN OF TIRUPATI, INDIA

Objective: According to Food Safety and Standards Authority of India (FSSAI) the preservatives, sodium benzoate and potassium sorbate belong to permitted class II preservatives. The aim of this study is to determine the concentration levels of these preservatives in food products that are consumed by school children and to assess the chronic dietary exposure by conducting the Total Diet Study (TDS).Methods: The quantitative determination was carried out by UV spectrophotometer. The absorbance for sodium benzoate and potassium sorbate were measured at 228 and 250 nm respectively. The 24-hour diet recall method was used to estimate the amount of food ate in last 24 hours. For estimation of preservative exposure dietary modelling techniques were utilized which combine the amount of preservative concentration present in that food with the amount of food consumed. Then the dietary exposure was assessed by considering the Acceptable Daily Intake (ADI).Results: The results include chemical concentration levels of the foods analyzed as well as estimated dietary exposures and contributions to the exposure from different foods. The obtained mean concentration of sodium benzoate was found to be425 ppm for sauces, 161 ppm for pickles and 80 ppm for soft drinks. Potassium sorbate was found to be 130 ppm for fruit juices,302 ppm for jellies and 380 ppm for jams. The highest mean dietary exposure for both the preservatives was observed in children of 2-7 years age group, the percentage exposure of sodium benzoate was 33% of the ADI and potassium sorbate was 17 % of the ADI.Conclusion: This study can enlighten the public on the consumption of preservative containing food products within the limit and encourages to eating fresh preservative free foods.Â

Demonstration of Spatial Self Phase Modulation based photonic diode functionality in MoS2/h-BN medium

Spatial self-phase modulation (SSPM) is the optical nonlinear process and is a result of spatially varying refractive index profile along the line of propagation in a medium. SSPM is proved to be a method to demonstrate different photonic functionalities. Transition metal dichalcogenides play a key role in 2D nanophononics due to their unique and fascinating properties. MoS2 is the widely studied layered TMDs among all other 2D materials. This paper demonstrates such photonic functionality using thermally induced nonlinear optical response SSPM method, of MoS2 nano bottles. Thermally induced nonlinear optical parameters have been estimated by utilizing the saturable absorption response of h- BN, the nonreciprocal light propagation has been achieved. The diode actions have also been demonstrated in liquid-solid and solid-solid devices with the help of passive elements

Effect of Tool Angle on Friction Stir Welding of Aluminum Alloy 5052: Role of Sheet Thickness

The technique of friction stir welding (FSW) does offer several advantages over conventional welding techniques. In this paper is presented the results of an investigation aimed at understanding the effect of tool angle on welding of sheets of commercially pure aluminum and aluminum alloy AA5052-H32 having different thickness. The present study demonstrates the feasibility of using friction stir welding (FSW) for joining two different thickness sheets of commercially pure aluminum (t = 1.5 mm and t = 2.0) with sheets of aluminum alloy 5052-H32 having thickness of 1.6 mm and 2 mm. It was found that the tool angle does play a major role in the welding of sheets having different thickness. Formation of the FSW zone was analyzed both macroscopically and microscopically. The tensile properties of the joints were evaluated and correlated with the formation and presence of the FSW zone. From this study it was found that the tool angle for commercially pure aluminum having a thickness of 1.5 mm and 2.0 mm is 2.580. The tool angle is 1.910 for the sheets of AA 5052-H32 having a thickness of 1.6 mm and 2 mm. The joint efficiency of the friction stir welded AA 5052-H32 was 87.5 pct. when compared to the base material. The hardness was also observed to drop in the region of the weld. Key words: Friction stir welding, tool angle, aluminum alloy (AA5052-H32), Hardness, macrostructure, microstructure