Modelling of sterilization and air exchange rates for indoor environment: An application to effect of ozone concentration on room bacteria

680-683Under the assumption of well mixed indoor air, the effect of ozone generated from an ozonizer on the room bacteria is mathematically modelled. The model computations give the effective air exchange rate, sterilization rate, ozone destruction rate and the release rate of ozone for ozonizer

Levitation dynamics of a collection of charged droplets in an electrodynamic balance

The study explores the stable levitation and self-organization of charged multi-drop assemblies in a large sized quadrupole trap both experimentally and through numerical simulations. The trap is benchmarked by comparing single drop levitation experiments with numerical simulations. Important observation and findings of the study are: (i) long time stabilization and formation of patterns of droplet collections over a range of operating parameters (ii) Numerical prediction of polygonal patterns for few drop (2 to 8) systems and lattice structures for many drop (>10) systems, (iii) Numerical prediction of Non-dependence of the inter-drop spacing on droplet charge for similarly charged drops, consistent with earlier analytical formulations [Aardahl et al., J. Aerosol Sci. 28, 1491-1505 (1997)], (iv) numerical observation of two drops oscillations with a secular frequency distinctly higher than the single drop Dehmelt frequency (v) Simulations of a systematic transition from disordered to coulombic crystals with mean size increasing with the number of levitated drops (N) as similar to N-0.29. The experimental observations on different patterns and lattice spacings are closely reproduced by simulations. Published by AIP Publishing

A simple and efficient one pot synthesis of 2,4 dioxopyrimidine carbonitrile and 4-oxo-2-thioxopyrimidine carbonitrile derivatives using ammonium chloride under solvent free conditions

997-999Various substituted 4-oxo-2-thioxopyrimidine and 2,4-dioxo-pyrimidine derivatives have been synthesized by ternary condensation of ethyl cyanoacetate, aldehyde and thiourea/urea by using ammonium chloride. Structures of all the products are supported by their spectral data

Meglumine Sulfate: An Efficient Catalyst for the Synthesis of Quinoxalines

Meglumine Sulfate: An Efficient Catalyst for the Synthesis of Quinoxaline

Unprecedented “In Water” Imidazole Carbonylation: Paradigm Shift for Preparation of Urea and Carbamate

The first “In Water” imidazolecarbonylation of amine is described. A one pot reaction of carbonylimidazolide in water with a nucleophile provides an efficient and general method for the preparation of urea, carbamates and thiocarbamates. Use of an anhydrous solvent and an inert atmosphere could be avoided. Product precipitate out from the reaction mixture and can be obtained in high purity by filtration, resulting in a simple and scalable method

A walk-in type calibration chamber facility for 222Rn measuring devices and inter-comparison exercises

A walk-in type 222Rn calibration chamber of volume 22.7 m3, which has traceability to international standards, is established at the Centre for Advanced Research in Environmental Radioactivity, Mangalore University, India. It has a human–machine interface communication system, a programmable logic controller and sensor feedback circuit for controlling and data acquisition of relative humidity (RH) and temperature (T). An innovative method for the generation of desired 222Rn concentration (a few hundred Bq m−3 up to about 36 kBq m−3) using soil gas as a source was adopted. Leak rates of 222Rn from the chamber for the mixing fan ON and OFF conditions were determined to be 0.0011 and 0.00018 h−1 respectively. With the exhaust system fully turned on, the maximum clearance rate of the chamber was 0.58 ± 0.07 h−1. Excellent spatial uniformity in 222Rn concentration in the chamber was confirmed (with a mean value of relative standard deviation < 12%) through measurements at 23 locations using CR-39 film-based passive devices. Demonstration of calibration applications was performed using charcoal canister and PicoRad vials as the 222Rn adsorption devices. The study shows that gamma spectrometry is a convenient alternative approach to liquid scintillation analysis of PicoRad vials for 222Rn measurement