Safety mechanisms in lithium-ion batteries

With increasing use of lithium-ion power packs, reports of occasional incidents of severely debilitating and sometimes fatal tragedies appear in the news. This review analyzes possible scenarios that trigger such hazards before proceeding to discuss safety mechanisms such as pressure release valves, one-shot fuses, reversible and irreversible positive temperature coefficient elements, shutdown separators, chemical shuttles, non-flammable electrolytes and coatings

Contribution of leaf growth on the disappearance of fungicides used on tea under south Indian agroclimatic conditions

The sprayed chemicals on tea leaves disappear over a period of time by the influence of rainfall elution, evaporation, growth dilution, and photodegradation. Influence of plant growth on the four fungicides (hexaconazole, propiconazole, tridemorph, and c) was studied to know the constructive loss of fungicides. The study shows that residues of fungicides sprayed on tea shoots got diluted by the growing process. The expansion of a leaf took 8 to 11 d and more than 50% of the fungicide residues were cleaned out during this leaf expansion period. Under south Indian agroclimatic condition, the fungicides are sprayed at an interval of 10 d, so it is safe that the tea is harvested on the 10th day of the application of fungicides

Gas chromatographic method for the determination of hexaconazole residues in black tea*

A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most appropriate solvent mixture for extracting hexaconazole residues from black tea was n-hexane:acetone at 1:1 (v/v). The extract was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues