Removal of heavy metals from kaolin using an upward electrokinetic soil remedial (UESR) technology

An upward electrokinetic soil remedial (UESR) technology was proposed to remove heavy metals from contaminated kaolin. Unlike conventional electrokinetic treatment that uses boreholes or trenches for horizontal migration of heavy metals, the UESR technology, applying vertical non-uniform electric fields, caused upward transportation of heavy metals to the top surface of the treated soil. The effects of current density, treatment duration, cell diameter, and different cathode chamber influent (distilled water or 0.01 M nitric acid) were studied. The removal efficiencies of heavy metals positively correlated to current density and treatment duration. Higher heavy metals removal efficiency was observed for the reactor cell with smaller diameter. A substantial amount of heavy metals was accumulated in the nearest to cathode 2 cm layer of kaolin when distilled water was continuously supplied to the cathode chamber. Heavy metals accumulated in this layer of kaolin can be easily excavated and disposed off. The main part of the removed heavy metals was dissolved in cathode chamber influent and moved away with cathode chamber effluent when 0.01 M nitric acid was used, instead of distilled water. Energy saving treatment by UESR technology with highest metal removal efficiencies was provided by two regimes: (1) by application of 0.01 M nitric acid as cathode chamber influent, cell diameter of 100 mm, duration of 18 days, and constant voltage of 3.5 V (19.7 k Wh/m(3) of kaolin) and (2) by application of 0.01 M nitric acid as cathode chamber influent, cell diameter of 100 cm, duration of 6 days, and constant current density of 0.191 mA/cm(2) (19.1 k Wh/m(3) of kaolin).     

Influence of carbon fibre on formation kinetics of crosslinked copolymer from bisphenol A dicyanate and epoxy oligomer

The influence of carbon fibre on the curing kinetics of the prepolymer based on bisphenol A cyanurate and epoxy resin has been studied using infra-red spectroscopy. It was found that the curing process of the prepolymer is very complicated. It is shown that in curing the prepolymer a number of the sequential transformations of one ring structure into others occurs. An introduction of the carbon fibre (CF) of two types, original CF and modified CF (MCF) containing phosphate groups, affects strongly the prepolymer curing. Both CF and MCF accelerate the conversion rate of epoxy groups. In the case of cyanate groups, the former has practically no effect on their conversion whereas the latter decelerates strongly this process. In the present paper the influence of CF on the mechanism of the copolymer formation is considered.     

The use of hybrid anaerobic solid–liquid (HASL) system for the treatment of lipid‐containing food waste

The hybrid anaerobic solid–liquid (HASL) system was a modified two‐phase anaerobic digester developed for bioconversion of food waste. The aim of this study was to estimate the feasibility of the HASL system for the treatment of food waste with a high content of lipids. The presence of lipids in food waste increased the energy value of nutrients but could inhibit growth of methanogens. The positive effect of lipids on the performance of anaerobic digestion dominated when the contents of lipids were in the range from 20 to 30% of total solids of food waste. Lipid contents of 40% diminished the production of volatile fatty acids in the acidogenic reactor as well as biogas production and the concentration of total bacteria and methanogens in the methanogenic reactor. Therefore, the HASL system can be used for the treatment of lipid‐containing food wastes if the lipid content is below 40% of total solids. Copyright © 2005 Society of Chemical Industry     

Coherent anti-Stokes Raman scattering enhancement of thymine adsorbed on graphene oxide

Coherent anti-Stokes Raman scattering (CARS) of carbon nanostructures, namely, highly oriented pyrolytic graphite, graphene nanoplatelets, graphene oxide, and multiwall carbon nanotubes as well CARS spectra of thymine (Thy) molecules adsorbed on graphene oxide were studied. The spectra of the samples were compared with spontaneous Raman scattering (RS) spectra. The CARS spectra of Thy adsorbed on graphene oxide are characterized by shifts of the main bands in comparison with RS. The CARS spectra of the initial nanocarbons are definitely different: for all investigated materials, there is a redistribution of D- and G-mode intensities, significant shift of their frequencies (more than 20 cm^-1), and appearance of new modes about 1,400 and 1,500 cm^-1. The D band in CARS spectra is less changed than the G band; there is an absence of 2D-mode at 2,600 cm^-1 for graphene and appearance of intensive modes of the second order between 2,400 and 3,000 cm^-1. Multiphonon processes in graphene under many photon excitations seem to be responsible for the features of the CARS spectra. We found an enhancement of the CARS signal from thymine adsorbed on graphene oxide with maximum enhancement factor about 10⁵. The probable mechanism of CARS enhancement is discussed.     

An adaptive learning algorithm for a wavelet neural network

Abstract: An optimal online learning algorithm of a wavelet neural network is proposed. The algorithm provides not only the tuning of synaptic weights in real time, but also the tuning of dilation and translation factors of daughter wavelets. The algorithm has both tracking and smoothing properties, so the wavelet networks trained with this algorithm can be efficiently used for prediction, filtering, compression and classification of various non-stationary noisy signals.     

Polymer resins with epoxy end groups obtained from hydrocarbon pyrolysis C9 fraction

Polymer resins with epoxy groups (PREGs) are synthesized by radical copolymerization of hydrocarbon pyrolysis C₉ fraction using 1,2-epoxy-3-tert-butylperoxypropane as the initiator or by copolymerization of the ED-20 epoxy resin modified by tert-butyl hydroperoxide. The effect of the initiator nature and quantity, temperature and reaction time on the yield and characteristic of PREGs are examined. The structure of synthesized products is established by chemical methods and IR spectroscopy. The structurization of ED-22 epoxy resin is studied in the presence of polyethylenamine using 10 and 25 mass% of PREG.     

Special state standard for the unit of radionuclide activity in gases

Conclusions As a result of the investigations of the standard of the unit of radionuclide activity in gases carried out by the All-Union Scientific Research Institute for Physical and Radio Engineering Measurements, it follows that the standard of the unit of radionuclide activity in gases ensures the reproduction of the activity unit with an error of l–2% in the activity range 10–20×10⁴ dis/sec·m³.With the help of working standards using gaseous radioactive sources, the transfer of the size of the activity unit to test measuring instruments is ensured, and from these to working measuring instruments through a planned verification scheme.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 8–10, November, 1971.     

An investigation of the differential cross section for elastic scattering of 19.4-Mev protons by nuclei of T,He3, He4, N14, and O16

The differential cross section has been measured for elastic scattering of 19.4-Mev protons by nuclei of T, He³, He⁴, N¹⁴, and O¹⁶. The proton source was a linear accelerator. The protons were scattered on A gas target at pressures from 520 to 620 mm Hg. The scattered protons were recorded by two CsI(T1) crystal scintillation counters. The differential cross sections for T, He³, and He⁴ have about the same variation, but the minimum for He⁴ is somewhat higher and is displaced in the direction of small angles. At small angles the cross section for T is considerably higher than for He³ and He⁴.The differential cross sections for N¹⁴ and O¹⁶ are also of similar structure, but the depth of the minima and height of the maxima are greater for O¹⁶ than for N¹⁴. Comparison of our data with that of other authors shows that as the atomic number increases for a given proton energy, the positions of the minima for all elements are displaced towards smaller angles. As the energy of the scattered protons increases, the minima in the differential cross section for T and He³ is displaced towards larger angles, whereas for all heavier nuclei this displacement is towards smaller angles.In conculsion the authors express their gratitude to L. V. Kurchatov, K. D. Sincinikov, E. K. Zavoisky, and A. P. Klyucharev for valuable advice and constant attention to the work, to P. V. Chikin who carried out the work on the clectronic circult, and to the maintenance personnel of the accelerator under the direction of A. M. Smirnov, and to A. L. Bazi for discussion of the results.