Dynamic Performance Analysis of Permanent Magnet Hybrid Stepper Motor by Transfer Function Model for Different Design Topologies

This paper discuss about dynamic performance analysis of permanent magnet hybrid stepper motor during single stepping by transfer function model for eight topologies using PDE toolbox of Matlab, for different current densities for two types of core materials.. These results suggest modifications for better performance of the PMH stepper motor for better dynamic response during single stepping.DOI:http://dx.doi.org/10.11591/ijece.v2i2.19

Ventilation coefficient and boundary layer height impact on urban air quality

In the present study, ventilation coefficient (VC) was estimated in order to understand the concentration of pollutants over the urban region of Hyderabad during 2009–2011. Nocturnal boundary layer height (BLH) was calculated using the accurate (0.2% for Refractivity Profiles) high vertical resolution global positioning system radio occultation (GPSRO), Constellation Observing System for Meteorology Ionosphere and Climate (COSMIC)-derived one-dimensional variational (1-DVAR) refractivity profiles, and observations of boundary layer LIDAR (BLL). The statistical results revealed that the coefficient of determination (R2) between LIDAR- and GPSRO-estimated BLH is 0.51, whereas that for VC is 0.68. The maximum BLH observed during the study period was maximum in the summer season and the minimum was observed in monsoon season, whereas the maximum VC was observed during summer and the minimum in winter. When the BLH and VC are low, the pollutant concentration of black carbon (BC) is higher and vice versa. This means that the dispersion of pollutants in the lower atmosphere is due to convective mixing. It was found that high VC values could dilute air pollutants whereas low values leads to more pollution

Evidence of stratosphere–troposphere exchange during severe cyclones: a case study over Bay of Bengal, India

The role of cyclones in atmospheric mixing and troposphere–stratosphere exchange of ozone and relative humidity (RH) is investigated for two severe cyclones PHAILIN and HUDHUD over the Bay of Bengal. Ozone concentration from Microwave Limb Sounder along with RH profiles obtained from Sounder for Probing Vertical Profiles of Humidity instrument aboard Meghatropiques platform, upon analysis at different pressure levels, revealed a rapid increase in RH and ozone concentration from lower troposphere to upper troposphere one day prior to landfall for both cyclones. The Weather Research and Forecasting model based simulations of convergence and divergence were used to estimate mass and momentum exchanges between troposphere and stratosphere which suggest the drastic increase in RH and ozone concentrations in UT due to high convective activity. Variations in the vertical profiles of ozone and RH during cyclonic period acts as a tracer for stratosphere–troposphere exchanges during peak cyclone intensity period