Mrinmoy Chakraborty

Generation and Dispersion of Total Suspended Particulate Matter Due to Mining Activities in an Indian Opencast Coal Project

The knowledge of ambient air quality plays an important role in assessing the environmental scenario of the region. The ambient air quality status in the vicinity of the mining activities forms an indispensable part of the Environmental Impact Assessment Studies. The quality of ambient air depends upon the concentrations of specific contaminants, the emission sources and meteorological conditions. The mining activities contribute to the problem of air pollution directly or indirectly (Trichy ,1996, Corti and Senatore, 2000, Baldauf et al., 2001 and Collins et al., 2001). Coal dust is the major pollutant in the air of open cast coal mining areas. (Kumar et al., 1994, Vallack and Shillito, 1998. and CIMFR, 1998) The primary source of fugitive dust at fully operational surface mine may include overburden (OB) removal, blasting, mineral haulage, mechanical handling operations, minerals stockpiles and site restoration (Appleton et. al. 2006). Major air pollutants due to opencast mining are total suspended particulate matter and respirable particulate matter whereas concentration of SO2 and NOX is negligible (Sinha and Banerjee, 1997, CIMFR, 1998, Banerjee, 2006, and Trivedi et. al., 2009). Transportation of materials is the major source of TSPM generation in the mining areas. The vehicle and haul road intersection has been identified as the most critical source producing as much as 70% of total dust emitted from surface coal mines (Muleski and Cowherd, 1987, Sinha and Banerjee, 1997, Ghose and Majee, 2002), while it was accounted to be 80-90% of the PM10 emission (Cole and Zapert, 1995). Maximal concentrations of particulate matter are generally occurred during winter and minimal in the rainy season.(Ghose and Majee, 2000, Tayanc, 2000, Reddy and Ruj, 2003). However, in certain urban areas maximal concentrations of particulate matters are also observed in summer season (Crabbe et al., 2000, Almbauer et al., 2001, Triantafyllou et al., 2002 and Triantafyllou, 2003). The dispersion of particulate matter follows the annual predominant wind direction of an area (Corti and Senatore, 2000, Baldauf et al., 2001 and Pandey et. al., 2008). Such a large amount of dust generated cause safety and health hazards such as poor visibility, failure of mining equipment, increased maintenance cost etc which ultimately lowers the productivity. A prolonged exposure to air borne dust may cause to damage of lung tissues of the miners which may further lead to pneumoconiosis or black lung disease. The maximum tissue damage is caused by the dust of 5 microns lesser sizes since such particles reach the alveoli of the lung (Peavey et. al, 1985). These air pollutants reduce air

LP-HS Logic Evaluation on TSMC 0.18μm CMOS Technology

Present paper analyses different aspects of “Low Power-High Speed” (LP-HS) logic in favour of present day ULSI system focus. At first, the speed-power efficiency of LP-HS logic is investigated by d...

L shaped DGS integrated triangular microstrip antenna with frequency tuning characteristics

A L-shaped defective ground structure (i.e. DGS) is implemented in the ground surface and length of the DGS is revised accordingly to achieve the lower application frequency bands viz. GSM band, Bluetooth band and WiMax band respectively. As a consequence, frequency tunable characteristics with optimal bandwidth and gain is observed in the application frequency bands for proposed antenna.

Study on LP-HS logic for high performance digital applications

Present paper investigates applicability of “Low Power-High Speed” (LP-HS) logic for high performance digital system design. LP-HS logic, proposed after Constant Delay Logic (CDL) to overcome problems associated with its predecessor. In the proposed work at first the speed-power performance of LP-HS Logic is investigated by designing some basic function circuits like buffer, OR, XOR etc. The DC sweep analysis is done on LP-HS Buffer to find Noise Margin (NM) characteristic and the temperature effect on logic-threshold voltage. Then the corner analysis with TT (Typical), FF (Fast) and SS (Slow) execution-model is performed. To find the worst case response Delay and PDP variation is analyzed. All the simulations are performed on TSMC 0.18μm CMOS technology using Tanner EDA V.13.

Suppression and controlling of higher order modes in microstrip antenna with composite resonator

Suppression of higher order harmonic modes of the resonating frequency in a microstrip antenna has been proposed in the paper. Controlling harmonics in the microstrip antenna has been implemented by integrating composite resonators at the microstrip feed line which resulted in elimination of higher order modes occurring between the fundamental resonating frequency and the second harmonics of the microstrip antenna. The integration of the composite resonator in the microstrip feed line to suppress and control the higher order modes is the prime novelty of the paper.

Design and analysis of compact triangular microstrip antennas integrated with novel defective ground structure

In this paper triangular microstrip antenna with a novel defective ground structure are proposed. Without the defective ground structure (DGS) the structures are found to be resonant at 5.2 GHz. When the DGS are introduced a frequency shift of 5.2 GHz to 1.8 GHz is observed. The main essence of this paper is the miniaturization of the antenna.

Multiple saw tooth shaped DGS integrated compact circular patch antenna for 2.4/5.2/5.8 GHz WLAN band

A compact high performance tri-band coaxial probe fed circular microstrip antenna with two saw tooth shaped defected ground structures (DGS) for wireless local area network applications is proposed. In this paper, a circular microstrip antenna is designed for 5.2 GHz WLAN band (5.15–5.35 GHz). Now, two saw tooth shaped DGS structures are suitably introduced for achieving two additional frequency bands at 2.4 GHz, i.e. the Bluetooth band (2.4–2.48 GHz) and 5.8 GHz, i.e. the second WLAN band (5.725–5.825 GHz). The fabricated prototype of the proposed antenna has an overall size of 34.4 mm × 26.6 mm. The integrated DGS structures also improve the performance of the antenna and reduce the patch area by 84%. Experimental results show that the antenna has good directional radiation patterns and gains over the three frequency bands. In addition, the effect of the variation of different parameters of the proposed antenna with DGS structures on its electromagnetic performance is extensively studied and discussed in detail.

Elimination of higher order modes in wearable microstrip antenna

Reduction of higher order harmonic modes of the fundamental operating frequency in a wearable microstrip antenna has been proposed. Controlling harmonics in the microstrip antenna has been implemented by integrating simple I shaped resonator at the microstrip feed line. As a result higher order modes occurring between the fundamental resonating frequency and the second harmonics of the wearable microstrip antenna have been successfully suppressed.

Dielectric Resonator Integrated high gain SIW antenna array

In the given paper a Dielectric Resonator Integrated Substrate Integrated Waveguide (SIW) antenna array is proposed for enhanced performance. Two cylindrical structures are mounted on the antenna to form a dielectric resonator, along with periodic coaxial via and resonating slots in the top surface which resulted in an enhanced gain of about 13.6dB. The different antenna parameters are analyzed and thus it can be concluded that the proposed dielectric resonator integrated SIW antenna array can be suitably used for wireless applications.

2D SEM and 3D XCT investigation of in-situ Al-Cu-TiB2 semi-solid forged composites

The present work compares the 2D and 3D distribution of TiB2 particles in a semisolid processed Al-4.5%Cu-5wt.% TiB2 in-situ composite prepared by flux assisted synthesis. The composite was synthesized by the reaction of K2TiF6 and KBF4 salts in molten Al-4.5Cu alloy held at 800 oC for an hour. The extent of distribution of TiB2 particles was investigated using Field Emission Scanning Electron Microscopy (FESEM) and X-ray computed tomography (XCT) to obtain 2Dand 3D images respectively. The studies indicated improved distribution of TiB2 particles after semi-solid forging of composites (at 0.1 volume fraction of liquid and 50% reduction) as compared to as cast composites. The hardness of the semisolid forged composites showed a significant increase and is uniform in all directions. The increase in hardness could be attributed to particle fragmentation and its redistribution in the matrix. Further investigation will be needed to understand the mechanism of redistribution and investigate the mechanical properties of such composites in detail. Copyright