Middleware Technologies for Smart Wireless Sensor Networks towards Internet of Things: A Comparative Review

Wireless Personal Communications - Internet of Things (IoT) offers complex networks of connected devices, which are used to serve in the real-time environment. Interestingly, Wireless Sensor...     

Visible Light‐Induced,Metal‐Free Denitrative [3+2] Cycloaddition for Trisubstituted Pyrrole Synthesis

A metal‐free, regioselective synthesis of trisubstituted pyrroles has been developed through a formal [3+2] cycloaddition reaction between 2H‐azirines and nitroalkenes under visible light/photoredox‐catalyzed conditions. The reaction proceeds through 2H‐azaallenyl radical addition on β‐nitrostyrenes in a Michael fashion followed by a base‐mediated denitration reaction. The directive group influence of the nitro group controls the regiochemistry of the reaction.     

Dibutyltin oxide catalyzed aminolysis of oxalate to carbamate,oxamate and derivatives of imidazolidine trione

Catalytic aminolysis of oxalates by simple and substituted ureas has been shown to give carbamates, oxamates and derivatives of imidazolidine trione. Various substituted ureas and oxalates were screened to verify the applicability of the protocol. The role of dibutyltin oxide as catalyst, effect of solvent and reaction conditions on product distribution pattern has been discussed. Copyright © 2010 John Wiley & Sons, Ltd.     

Cacotheline as a reagent for the detection of ferrous and ferric iron

1. Cacotheline has previously been employed as a colorimetric reagent for the detection of Sn⁺² and V⁺³ ions. The present investigation covers its use as a reagent for the detection of Fe⁺² and Fe⁺³ ions. 2. Fe⁺² ions give a pink colour with a solution of cacotheline at a pH lying between 1.48 and 4.58 in the presence of a sufficient concentration of sodium oxalate, which serves to bind the Fe⁺³ ions by complex formation. At a pH below 1.24, only a very light pink colour is produced and this develops slowly. When the pH of the solution is about 5.2, a blue colour is obtained. The limit of identification is 1.5 γ and the concentration limit is 1 : 40,000 of Fe⁺². While testing for Fe⁺² at very low concentration, it is necessary to employ a very dilute solution of cacotheline (0.025%), while for solutions of higher concentrations saturated cacotheline solution (about 0.25%) is recommended. A detailed investigation has been made concerning the conditions determining the stability of the pink colour. 3. It has also been observed that sodium malonate, sodium citrate, sodium malate, sodium tartrate and sodium lactate are effective as complexing agents for binding Fe⁺³ ions. 4. Orthophosphate has not been found effective as a complexing agent under the conditions adopted, while pyrophosphate and metaphosphate have been found effective. 5. Fe⁺³ ions are reduced to Fe⁺² by exposure to sunlight or the light from a Philip's Repro lamp in the presence of the appropriate buffer solution and sodium oxalate.     

Determination of surface state distribution from pulsed MOS capacitor transients

The transient capacitance plots of metal oxide semiconductor capacitors are numerically computed taking into account the effect of the surface state distribution. For negligible minority carrier generation in the bulk and at the surface, the slope of a capacitance (C) vs time (t) curve is proportional to the surface state density. It is shown that a plot of t dC/dt vs ln t is a direct measure of the surface state density distribution.     

Deoximation with N-Haloamides1

Deoximation of different oximes to the corresponding carbonyl compounds has been carried out by using N-bromosuccinimide or N-chlorosuccinimide in good yields under mild conditions.     

Surface Modification by Atmospheric Pressure Air Plasma Treatment to Improve Dyeing with Natural Dyes: An Environment Friendly Approach for Leather Processing

The present study describes surface modification of leather using environment friendly atmospheric pressure dielectric barrier discharge (DBD) process to improve dyeing with natural dyes. Leather samples were exposed to dielectric barrier discharge produced in air. DBD plasma treatment changes morphology and chemical composition of the surface of leather samples. The chemical changes at leather surface are confirmed by Fourier transform infrared spectrometer. The morphology and chemical composition of leather surface is studied using scanning electron microscope and X-ray photoelectron spectroscopy. We observed significant improvement in dye uptake properties after air plasma treatment. Different species formed in plasma are identified using optical emission spectroscopy. Untreated and plasma treated samples were dyed with Eco-Garnet Brown, Eco-Hill Brown III, Eco-Turkey Red and Eco-Smoke Grey natural dyes. Dyeing behavior was assessed by spectroscopic measurement and by measuring fastness (wash and rub) properties. This has clearly indicated an increase in color intensity of plasma exposed leather as well as an increase in the dye uptake as compared to the untreated leather. Best results were obtained with Eco-Hill Brown III and Eco-Smoke Grey dyes. The study reveals that atmospheric pressure plasma has potential to become dry and eco-friendly process to modify leather surface to improve dye uptake properties with natural dyes.