B. Kumar

Design of Digital FIR Notch Filters from Second Order IIR Prototype

A straightforward method has been suggested for the design or FIR notch filters starting from a second-order DR prototype. By appropriate choice of its length, the frequency response of the designed FIR Filter can be made to match that of the llR prototype very closely. Explicit mathematical formulas for computing the required weights have also been given.

Evaluation of geochemical data of Yamuna River using WQI and multivariate statistical analyses: a case study

ABSTRACT This study is focused on the character and classification of Yamuna River water quality using secondary data. The application of water quality index (WQI), cluster analysis (CA), principal component analysis (PCA), multiple regression analysis (MRA) and discriminant analysis (DA) was investigated to assess the water quality status and evaluate the critical parameters with identification of most prominent polluted sites. During investigation of WQI, 67% of the total monitoring area falls under bad and very bad categories. CA classified 19 monitoring sites into 3 groups based on the properties of water quality. PCA obtained two principle components which suggest that domestic, industrial, municipal effluent and agricultural runoff are important pollution sources of Yamuna River. DA result indicates pH, COD, DO as most significant parameters, and are responsible for discriminating the groups. MRA obtained that TC, FC, NH4, COD, BOD and pH are dependable factors for controlling the river water quality. The trend line of Yamuna River water quality through simple regression indicated that the trend values of COD, BOD, NH4, TKN, TC and FC are continuously increasing in the river system while the negative trend line of DO suggested that the water quality of Yamuna could be under hypoxic condition in near future.

Characterization of hydrogeochemical process and evaluation of water quality of seven geothermal springs, Bakreswar, India

A study was conducted in seven geothermal springs located in Bakreswar, District Birbhum, West Bengal, India, in order to assess numerous geochemical processes which were responsible for chemical composition of thermal and mineralized water. The study area lies over the Sone, Narmada, and Tapti lineament of Precambrian Chotanagpur Gneissic Complex. Water chemistry has been carried out based on reaction stoichiometry and geo-statistical tools to identify geochemical process. Piper and Gibbs diagram suggest that the spring water belongs to Ca2+-Mg2+-HCO3− + CO32− water type and are controlled by rock dominance. Dissolution and precipitation of calcite, dolomite, gypsum, and fluorite minerals were identified as principle source of major ions in seven geothermal spring water. Principle component analyses revealed that major ions of spring water are derived from geogenic processes such as weathering, dissolution, and precipitation of various minerals. Overall results suggest that major ions of the spring’s water are derived from natural origin because no evidence of anthropogenic sources was observed during the study period. This study has also revealed that water quality of spring’s water is not suitable for drinking purposes and quite suitable for irrigation because of high abundance of Na+, K+, Cl−, and HCO3− ions.

Theoretical Analysis of Thermally Induced Structural Deformation and Relaxation of Silicon Wafer

This work is focussed on the modeling and simulation of structural deformation of silicon wafers during their initial heat-up in a CVD reactor chamber, prior to the chemical vapor deposition process. The wafer structural deformation can lead to some detrimental defects that are unacceptable for semiconductor device processing. In this work, we have developed a numerical model to simulate the wafer structural deformation as a function of some key process parameters. The main objective of this simulation work is to provide guidance on the optimal process conditions at which the wafer deformation and the resulting defects can be minimized.