Distribution of products around a burning droplet: an analytical approach

A knowledge of the concentration distribution around a burning droplet is essential if accurate estimates are to be made of the transport coefficients in that region which influence the burning rate. There are two aspects of this paper; (1) determination of the concentration profiles, using the simple assumption of constant binary diffusion coefficients for all species, and comparison with experiments; and (2) postulation of a new relation for the therinal conductivity, which takes into account the variations of both temperature and concentrations of various species. First, the theoretical concentration profiles are evaluated and compared with experimental results reported elsewhere [5]. It is found that the agreement between the theory and experiment is fairly satisfactory. Then, by the use of these profiles and the relations proposed in the literature for the thermal conductivity of a mixture of nonpolar gases, a new relation for thermal conductivity: K = (A1 + B1 T) + (A2 + B2 T) xr (21). is suggested for analytical solutions of droplet combustion problems. Equations are presented to evaluate A1, A2, B1, and B2, and values of these terms for a few hydrocarbons are tabulated.

Single-Shot Preparation of Crystalline Nanoplate LiFePO4 by a Simple Polyol Route

Nanoplate LiFePO4 is synthesized by a polyol route starting from only two reactants, namely, FePO4 and LiOH. The crystalline compound forms by refluxing a tetraethylene glycol solution consisting of FePO4 and LiOH at 335 degrees C without further heating of the reaction product.The nanoplates have average dimensions of 30 nm width and 160 nm length, as measured from transmission electron microscopy micrographs.The surface area of the LiFePO4 sample is 38 m(2) g(-1). Also, the sample is porous with a broadly distributed pore around 50 nm. The electrodes fabricated out of the nanoplate of LiFePO4 exhibit a high electrochemical activity. Discharge capacity values measured are 160 and 100 mAh g(-1) at 0.15C and 3.45C, respectively. A stable capacity of about 155 mAh g(-1) is measured at 0.2C over a 50 charge-discharge cycle. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3425730] All rights reserved.

A Simple and General Strategy for the Design of Fluorescent Cation Sensor Beads

Chenodeoxycholic acid based PET sensors for alkali metal ions have been immobilized on Merrifield resin and on Tentagel. The fluorescence of the sensor beads is enhanced upon binding the cations. The modular nature of the sensor allows designing different sensors based on this concept.

Simple kinetic sensor to structural transitions

Driven nonequilibrium structural phase transformation has been probed using time-varying resistance fluctuations or noise. We demonstrate that the non-Gaussian component (NGC) of noise obtained by evaluating the higher-order statistics of fluctuations, serves as a simple kinetic detector of these phase transitions. Using the Martensite transformation in free-standing wires of nickel-titanium binary alloys as a prototype, we observe clear deviations from the Gaussian background in the transformation zone, indicative of the long-range correlations in the system as the phase transforms. The viability of non-Gaussian statistics as a robust probe to structural phase transition was also confirmed by comparing the results from differential scanning calorimetry measurements. We further studied the response of the NGC to the modifications in the microstructure on repeated thermal cycling, as well as the variations in the temperature-drive rate, and explained the results using established simplistic models based on the different competing time scales. Our experiments (i) suggest an alternative method to estimate the transformation temperature scales with high accuracy and (ii) establish a connection between the material-specific evolution of microstructure to the statistics of its linear response. Since the method depends on an in-built long-range correlation during transformation, it could be portable to other structural transitions, as well as to materials of different physical origin and size.

Simple equidistant firing delay scheme for 3-phi thyristor converters

A simple firing delay circuit for 3-φ fully controlled bridge using a phase locked loop is described. The circuit uses very few components and is an improved scheme over the existing methods. The use of this circuit in three-phase thyristor converters and 'circulating current free' mode dual converters is described.

Chiral synthons from carvone, Part 40. A simple, enantiospecific approach to both enantiomers of 1 alpha,25-dihydroxyvitamin D-3 A-ring precursors from R-carvone

A simple and direct approach to both enantiomeric series of A-ring derivatives of 1 alpha,25-dihydroxyvitamin D-3 and the corresponding 1 alpha,3 alpha-derivatives, starting from the abundantly available R-carvone, is described. (C) 2000 Elsevier Science Ltd. All rights reserved.

Slip line field analysis of a simple plane strain closed‐die forging

A slip line field is proposed for symmetrical single‐cavity closed‐die forging by rough dies. A compatible velocity field is shown to exist. Experiments were conducted using lead workpiece and rough dies. Experimentally observed flow and load were used to validate the proposed slip line field. The slip line field was used to simulate the process in the computer with the objective of studying the influence of flash geometry on cavity filling.

A simple technique for approximate solutions of the Falkner-Skan equation

A simple, sufficiently accurate and efficient method for approximate solutions of the Falkner-Skan equation is proposed here for a wide range of the pressure gradient parameter. The proposed approximate solutions are obtained utilising a known solution of another differential equation.

A denotational semantics for the generalized ER model and a simple ER algebra

The recent spurt of research activities in Entity-Relationship Approach to databases calls for a close scrutiny of the semantics of the underlying Entity-Relationship models, data manipulation languages, data definition languages, etc. For reasons well known, it is very desirable and sometimes imperative to give formal description of the semantics. In this paper, we consider a specific ER model, the generalized Entity-Relationship model (without attributes on relationships) and give denotational semantics for the model as well as a simple ER algebra based on the model. Our formalism is based on the Vienna Development Method—the meta language (VDM). We also discuss the salient features of the given semantics in detail and suggest directions for further work.

A simple synthesis and characterization of CuS nanocrystals

Water-soluble CuS nanocrystals and nanorods were prepared by reacting copper acetate with thioacetamide in the presence of different surfactants and capping agents. The size of the nanocrystals varied from 3-20 nm depending on the reaction parameters such as concentration, temperature, solvent and the capping agents. The formation of nanocrystals was studied by using UV-visible absorption spectroscopy.