On The Realization of Active MURC Filter wth a Single Pole Amplifier
This paper presents the realization method of active MURC (multilayer uniformly distributed RC line) low pass filter with a single pole amplifier. The proposed circuit configuration consists of 2 MURC and one pole approximation of amplifier. The proposed circuit has a steeper rate of magnitude response at cut off and low sensitivities in the pass band. Experimental results of MATLAB simulations are carried
Active LPF using uniformly distributed RC line
The synthesis method of active low pass filters using uniformly distributed RC line has been published. This paper describes the Low Pass Filter (LPF) using double capacitive layers uniformly distributed RC line (DURC). This LPF circuit configuration with notch characteristics consists of DURC and a positive gain amplifier. The LPF using DURC can be used for anti-aliasing/smoothing filters for signal processors.
A quantitative measure of nitrifying bacterial growth.
Nitrifying bacteria convert ammonia (NH3) to nitrate (NO3-) in a nitrification reaction. Methods to quantitatively separate the growth rate of these important bacterial populations from that of the dominant heterotrophic bacteria are important to our understanding of the nitrification process. The changing concentration of ammonia is often used as an indirect measure of nitrification but ammonification processes generate ammonia and confound this approach while heterotrophs remove nitrate via denitrification. Molecular probe methods can tell us what proportion of the microbial community is nitrifying bacteria but not their growth rate. The technique proposed here was able to quantify the growth rate of the nitrifying bacterial populations amidst complex ecological processes. The method incubates [methyl-3H] thymidine with water samples in the presence and absence of an inhibitor of nitrification-thiourea. The radioactively labeled DNA in the growing bacteria was extracted. The rate of incorporation of the label into the dividing bacterial DNA was used to determine bacterial growth rate. Total bacterial community growth rates in full-scale and pilot-scale fixed-film nitrifying reactors and an activated sludge reactor were 2.1 x 10(8), 4.1 x 10(8) and 0.4 x 10(8)cell ml(-1)d(-1), respectively; the growth rate of autotrophic-nitrifying bacteria was 0.7 x 10(8), 2.6 x 10(8) and 0.01 x 10(8)cell ml(-1)d(-1), respectively. Autotrophic-nitrifying bacteria contributed 30% and 60% of the total bacterial community growth rate in the nitrifying reactors whereas only 2% was observed in the activated sludge reactor that was not designed to nitrify. The rates of ammonia loss from the nitrifying reactors corresponded to the rate of growth of the nitrifying bacteria. This method has the potential to more often identify factors that enhance or limit nitrifying processes in both engineered and natural aquatic environments.