Three‐dimensional analytical model of atmospheric dispersion of pollutant in a stable boundary layer

A three‐dimensional atmospheric dispersion model of a heavy admixture emitted from an elevated continuous point source is presented. Appropriate boundary conditions have been employed to model the effects of various removal mechanisms like deposition, settling and leakage of pollutants. This model takes care of variation of mixing layer height with heat flux, geostrophic drag by terrain and several meteorological parameters. A realistic form of variable eddy diffusivity is used in this model for a stable atmospheric condition. It has been found that the effect of settling of large particles is to reduce pollutant concentration always far away (horizontally as well as vertically) from the source. Whereas, in the lower part of the boundary layer near the source its effect is to increase concentration for small values of settling velocity and to decrease for larger values. The present model, being three dimensional in nature, is more suitable to assess the impact of point source emission.     

Effect of air and noise pollution on species diversity and population density of forest birds at Lalpahari, West Bengal, India

The Rajmahal-type quality stones for building purposes are found abundantly in Birbhum district, West Bengal, India, where stone mining and crushing have become the main industrial activity. Although crusher dust is injurious to health, demand for crushed stone is ever-increasing as a result of rapid infrastructural growth in the country. Most of the crusher units at Rampurhat are situated along the roadways adjacent to forest under Tumboni Beat of Rampurhat Range of Birbhum Forest Division. Excessive load of air pollution in this area has led to degradation of this forest. The status of the ambient air and noise level was evaluated. The effect of air and noise pollution on abundance and variability of birds in this forest have been compared to an almost non-polluted forest of the same bio-geographic zone. Both species diversity and population density of birds were found to decrease in the polluted forest, especially in the areas adjacent to crushers. For comparing the pollution status of two different forest sites and for establishing whether the density of birds have any correlation between the sites, the Student's t-test and the chi-square test were applied respectively. Most of the results proved to be significant.     

A numerical approach to unsteady behaviour of atmospheric pollutants from a point source

An atmospheric diffusion model for gaseous pollutants emitted from a continuous point source has been developed. Pollutants concentrations are obtained by solving numerically (implicit finite‐difference scheme) unsteady state one‐dimensional atmospheric transport‐diffusion equations. The surface dry deposition, gravitational settling and leakage of pollutants from the inversion layer are taken into account in the model.     

Electrodeposition of CoWP film: III. Effect of pH and temperature

Polarisation behaviour and nucleation mechanism of induced co-deposition of cobalt, tungsten and phosphorus from citrate electrolytes containing cobalt sulphate, sodium tungstate and sodium hypophosphite on copper disc electrode at various electrolyte pH values were studied using cyclic voltammetry and chronoamperometry, respectively. It was found that the onset potentials for reduction and oxidation gradually shifted towards more cathodic direction with increase in pH. Co-deposition of cobalt, tungsten and phosphorus occurred under diffusion control and followed instantaneous type of nucleation mechanism. The highest current efficiency (>70%) was found when the CoWP films were deposited from neutral or slightly acidic solution. Larger variation of film composition, cobalt from 48 to 74 at.%, tungsten from 13 to 38 at.% and phosphorus from 8 to 33 at.%, could be made by changing the pH of the electrolyte between 3 and 8. The films deposited from very acidic solutions contained larger amounts of tungsten and phosphorus and were amorphous; while the films deposited from near neutral solutions were polycrystalline and contained hexagonal cobalt. The surfaces of the amorphous films were smoother than those of the polycrystalline films. Needle-like dendritic crystallites were obtained when the films were deposited from basic solution or at elevated temperature.     

Activity recognition system using inbuilt sensors of smart mobile phone and minimizing feature vectors

Mobile phone is becoming a very popular tool due to having various user friendly applications with all flexible options. It is highly popular for its light weight, wearable and comfortable uses. Many extrinsic habitat of human being can be monitored by the help of inbuilt sensors and its application software. This has appealing use for healthcare applications using exploitation of Ambient Intelligence for daily activity monitoring system. Here, a standard dataset of UCI HAR (University of California, Irvine, Human Activity Recognition, http://archive.ics.uci.edu) is used for analysis purpose. Naive Bayes Classifier is used for recognition of runtime activities minimizing dimension of large feature vectors. Threshold based condition box is designed by us and finally these two results are compared with that of another classifier HF-SVM (Hardware Friendly-Support Vector Machine) of previous related work.     

Levy distributed parameter control in differential evolution for numerical optimization

Differential evolution (DE) algorithm is a population based stochastic search technique widely applied in scientific and engineering fields for global optimization over real parameter space. The performance of DE algorithm highly depends on the selection of values of the associated control parameters. Therefore, finding suitable values of control parameters is a challenging task and researchers have already proposed several adaptive and self-adaptive variants of DE. In the paper control parameters are adapted by levy distribution, named as Levy distributed DE (LdDE) which efficiently handles exploration and exploitation dilemma in the search space. In order to assure a fair comparison with existing parameter controlled DE algorithms, we apply the proposed method on number of well-known unimodal, basic and expanded multimodal and hybrid composite benchmark optimization functions having different dimensions. The empirical study shows that the proposed LdDE algorithm exhibits an overall better performance in terms of accuracy and convergence speed compared to five prominent adaptive DE algorithms.     

Study of sulphur in Assam coals by X-ray photoelectron spectroscopy

X-ray photoelectron spectroscopy (XPS) has been used to study the nature and content of sulphur contained in coal samples from Assam. In each case two sulphur 2p (S 2p) peaks were observed. The 169–171 eV 2p peak corresponds to sulphate, whilst the 164–165 eV peak is assigned to S in iron sulphide compounds such as pyrite, marcasite, etc. and also organic sulphur. The complete absence of a 169–171 eV S peak from a coal sample from which both pyritic and sulphate sulphur were removed by hydrodesulphurization strongly indicates that the remaining 164.7 eV S 2p peak corresponds to the total organic sulphur present in the coal.     

Foreword: Special Issue Micro 2017

Microsystem Technologies -