Polychlorobiphenyls: problems of the pollution of the environment and technological neutralisation methods

Abstract

Cylindrical pipes are widely used in industries such as nuclear power plants and micro total analysis systems (mTAS). Measuring the flow rate of fluid in such pipes is critical. Ultrasonic flowmeters are noncontact, nondestructive, and easy-to-use devices, and are therefore widely used. However, typical bulk-wave-based ultrasonic flowmeters cannot be used for pipes narrower than the wavelength of bulk waves. For such pipes, we are currently developing a ''guide wave flowmeter'' that uses guide waves instead of bulk waves. Previously, we theoretically and experimentally investigated a pipe filled with quiescent fluid for all modes [Jpn. J. Appl. Phys. 45 (2006) 4573]. In this study, we expanded our theoretical investigation to a cylindrical pipe containing flowing fluid, and then compared the results with experimental results. Both the theoretical and experimental results revealed that the flow rate can be determined by measuring the sound velocity (propagation time) of guide waves. This is the operating principle of our guide wave flowmeter.

Features of polychlorinated biphenyls nitration

“…IR spectra were registered using a Perkin-Elmer Spectrum One spectrophotometer. 1 H NMR spectra of the individual polychlorinated biphenyls IIa and IVa-VIa coincided with the reference data [17,21]. The congeners mixture IIIa was a viscous yellow liquid, bp 173-182°С (5 mmHg).…”

“…Mass spectrum recording conditions were as follows: quadrupole detector, scanning over the whole ion current at mass range of 20-1000 Da; EI at 70 eV. 1 Н NMR spectra were registered using a Bruker DRX-400 spectrometer at 400 MHz with reference to Me 4 Si in CD 3 OD. Elemental analysis was performed using a Perkin-Elmer CHN РЕ 2400 automated analyzer.…”

“…In particular, the thermal, pyrotechnical, electrochemical, biological, and chemical methods have been described (cf. [1,2]). Hydrodechlorination [3] has been recognized as the most important chemical method of polychlorinated biphenyls neutralization, whereas other processes (substitutive dechlorination, oxidation, etc.)…”

QSPR models for prediction of half wave potentials of some chlorinated organic compounds using SR-PLS and GA-PLS methods

“…2-chloro-and 4-chlorotoluene are used for the industrial production of pesticides and dyes [11]. Polychlorinated toluenes have also been proposed as substitutes for PCB in hydraulic systems [12]. Suitable procedures for the degradation of these compounds are therefore required.…”

“…These methods can be used to establish correlation between the similarities calculated using molecular descriptors and activity/chemical properties [25][26][27]. There are reports on the application of QSAR/QSPR for modelling different electrochemical parameters such as half wave potential [28][29][30][31]. The main aim of the present work was to develop two QSPR models based on genetic algorithm-partial least squares (GA-PLS) and stepwise regression-partial least squares (SR-PLS) to predict half-wave potentials (E 1/2 ) of some chlorinated organic compounds.…”