Synthesis, chemical characterisation and multifrequency measurements of poly N-(2-pyridyl) pyrrole for sensing volatile chemicals

N-(2-pyridyl) pyrrole was synthesized and polymerised to make a conducting polymer suitable for sensing volatile chemical species. The high frequency electrical responses of this material to methanol, acetone and ethyl acetate vapours were investigated. The results demonstrate a multiparametric technique for identification of volatile chemicals, on the basis of the changes in several electrical characteristics induced by the molecular interaction of adsorbed species on the conducting polymer.     

Sensitive fused-silica capillary gas chromatographic assay using electron-capture detection for indomethacin in ovine fetal fluids

A sensitive gas chromatographic (GC) method with electron-capture detection (ECD) has been developed to quantitate indomethacin (IND) in plasma, urine, amniotic, and tracheal fluids obtained from the pregnant sheep model. IND and the internal standard, alpha-methylindomethacin (alpha-Me-IND) are extracted by a simple liquid-liquid extraction procedure using ethyl acetate and derivatized with N-methyl-N-(tert.-butyldimethyl-silyl)trifluoroacetamide (MTBSTFA) at 60 degrees C for 50 min. The limit of quantitation (LOQ) is 1 ng/ml with a C.V. < 10% and signal-to-noise ratio > 10. Recoveries from all fluids were greater than 80%. Calibration curves were linear over the range of 1-32 ng/ml with a coefficient of determination (r2) > 0.999. Inter- and intra-day coefficients of variation were < 10% at concentrations of 2-32 ng/ml, and < 20% at the LOQ. Applicability of the developed method is demonstrated for a pharmacokinetic study of IND samples collected following long-term infusion of IND in a chronically instrumented ovine fetus.     

A study of inverse relaxation in some textile fibers

This article discusses the phenomenon of inverse relaxation in some textile fibers, namely cotton, ramie, wool, polyester, and viscose. If anextended viscoelastic specimen is allowed to recover a part of the deformation given to it, such that its tension has not become zero, the stress in it tends to increase. This phenomenon is termed as “inverse relaxation.” This property is measured in terms of an index referred to as the inverse relaxation index. The values of this index at various extension and retraction levels for the above materials are presented and discussed in this article.     

Effect of nonsteady wall temperature on forced-convection film boiling on a flat plate

Heat transfer associated with film boiling in forced-convection boundary-layer flow over a flat plate whose temperature is an arbitrary function of time is studied analytically using boundary-layer theory. The governing equations are solved by a perturbation technique. The effect on heat transfer of varying the fluid properties is discussed.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 19, No. 3, pp. 453–463, September, 1970.     

Low-power gradient-index microscope objective: design

We demonstrate use of the gradient-index (GRIN) spectral model to design an achromatic low-power GRIN microscope objective. This new GRIN microscope objective, using simpler lens configurations, exhibits a performance that is superior to the commercially available conventional objectives. We provide various design considerations and useful guidelines to suggest how the GRIN spectral model is useful in arriving at improved designs in performance and configurations for modern optical systems.     

A novel method ofrf powder sputtering

A new method ofrf sputtering by which thin films of metals, semiconductors and insulators can be sputtered from their respective powders, has been successfully demonstrated. The films have been characterized for their surface and crystal structure using conventional methods ofsem andtem. All the films are amorphous with a relatively smooth surface topography. The relative merits and demerits of the technique have been briefly discussed.     

Postembryonic development and reproduction inCorcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) on exposure to eucalyptus and neem oil volatiles

Postembryonic development and adult emergence ofCorcyra cephalonica (Stainton) were adversely affected in varying degrees when individuals were reared for the first 2 weeks of larval life or for a similar duration from the sixteenth day of their lives in an environment of eucalyptus oil volatiles. This was, however, not so in the progeny of parents exposed to these volatiles for only 5 min. Exposure of this pest to neem oil volatiles during larval stages for similar periods failed to produce such adverse effects. A marked decline in the reproductive potential, in terms of egg output and egg hatchability, of the moth was observed when the larvae were reared for the first 15 days in the presence of eucalyptus oil volatiles or when the parents were exposed for 5 min to such an environment during adult life. Thus, a carry over of the detrimental effect of the volatile(s) of this oil on the reproductive potential of the pyralid was indicated.     

OCSO-CA: opposition based competitive swarm optimizer in energy efficient IoT clustering

With the advent of modern technologies,IoT has become an alluring field of research.Since IoT connects everything to the network and transmits big data frequently,it can face issues regarding a large amount of energy loss.In this respect,this paper mainly focuses on reducing the energy loss problem and designing an energy-efficient data transfer scenario between IoT devices and clouds.Consequently,a layered architectural framework for IoT-cloud transmission has been proposed that endorses the improvement in energy efficiency,network lifetime and latency.Furthermore,an Opposition based Competitive Swarm Optimizer oriented clustering approach named OCSO-CA has been proposed to get the optimal set of clusters in the IoT device network.The proposed strategy will help in managing intra-cluster and inter-cluster data communications in an energy-efficient way.Also,a comparative analysis of the proposed approach with the state-of-the-art optimization algorithms for clustering has been performed.     

A single server feedback retrial queue with collisions

A Markovian single server feedback retrial queue with linear retrial rate and collisions of customers is studied. Using generating function technique, the joint distribution of the server state and the orbit length under steady-state is investigated. Some interesting and important performance measures of the system are obtained. Finally, numerical illustrations are provided.