Scientific Journal of KubSAU

Polythematic online scientific journal
of Kuban State Agrarian University
ISSN 1990-4665
AGRIS logo UlrichsWeb logo DOAJ logo
Search by author's name Search by title
Sort by: Date Title Views
213 kb

QuЕChERS SAMPLE PREPARATION IN THE DETERMINATION OF PESTICIDES OF DIFFERENT CHEMICAL CLASSES BY HPLC

abstract 1321708011 issue 132 pp. 117 – 127 31.10.2017 ru 521
The method has been developed of simultaneous determination of active ingredients of different kinds of pesticides in biological tissues (fish liver) by applying HPLC with ultra-violet detection and the rapid method of QuEChERS sample preparation. We defined optimum volume and composition of the reagents for the extraction, time of centrifugation and ultrasound treatment, the origin and composition of sorbents that ensure maximum extraction of the substances studied and further cleanup of interfering substances. Acetonitrile was used as a solvent. The extraction was carried out in the presence of a buffering mixture - trisodium citrate dihydrate and disodium citrate hemihydrate. Bondesil PSA bulk sorbents (alkylated amine containing two amine functional groups - secondary and primary) and C18E (reversed-phase sorbent based on silica gel with grafted octadecylsilane groups were used to purify the extract from coextractable substances (fats, proteins, sugars, organic and fatty acids, pigments and other impurities). The degree of extraction of the analyzed active ingredients of pesticides from the liver of fish was 79%. The detectable pesticide concentrations ranged from 0,4 to 0,97 mg/kg. The relative standard deviation of the analysis results amounted to 0,01-0,14
181 kb

RESEARCH IN MICRODEFICIENCY OF POLYMERS (ELASTOMER COMPOSITIONS) UNDER UNIAXIAL DEFORMATION

abstract 1271703062 issue 127 pp. 885 – 894 31.03.2017 ru 506
Macrodeficiency of polymeric materials, including the pervasive one, is a consequence of the development of initial microdefects which appear in polymers both due to external factors and during their processing. This article solves the task of identification the interrelation and interdependence of structural microdefects of various polymeric materials, consisting in the estimation of the structural parameters under uniaxial deformation. It is experimentally shown that the process of changing microdefects in the material bulk begins to flow more intensely during deformation of the material, having anisotropic structures in the bulk. Change of the parameters of microdefects is not observed compared to the starting material at small quantities of the deformation. In the area of deformation corresponding to the transition of the material from isotropic to anisotropic state parameters of microdefects do not depend on the degree of deformation of the sample, and abrupt changes of the parameters of microdefects are observed after completing the formation of anisotropic patterns. It is shown experimentally the identity of the parameters of microdefects in the bulk material (rubber-based natural caoutchouc) during deformation with the quantities of local deformations at the edge of the artificially created macrodefects. Under uniaxial deformation more than 280-300% and the growth of the quantities of local deformations come out at the edge of the artificially created macrodefects and normalized linear dimension k and decrease the total number n of microdefects
126 kb

RESEARCH IN MICRODEFICIENCY OF POLYMERS (RUBBERS AND RUBBERIZED FABRICS) USING EXPRESS TECHNIQUE OF ASSESSMENT BY THE SORPTION AND WEIGHT METHOD

abstract 1181604048 issue 118 pp. 817 – 826 29.04.2016 ru 704
Macrodeficiency of polymeric materials, including the pervasive one, is a consequence of the development of initial microdefects which appear in polymers both due to external factors and during their processing. In the article, the problem of the detection of structural microdeficiency of various polymeric materials through an assessment of their structural parameters is solved. The considered materials possess approximately identical degree of crystallinity (60 – 66%), but different density. The express assessment technique of polymeric materials microdeficiency by the sorption method with the use of the academician M. M. Dubinin’s theory of volumetric micropore filling is developed and evaluated. On the basis of a quantitative assessment of sorption processes in polymeric materials, including elastomeric compositions – rubbers and rubberized fabrics, the existence of the initial local microdefects arising in the course of synthesis is established. In real polymeric materials, including elastomeric compositions – rubbers and rubberized fabrics, the existence of the initial local microdefects arising in the course of synthesis is established (the number of microdefects n varies from 1x1017 sm-3 to 6x1019 sm-3 , and the rated linear size k – from 2 nm to 7 nm). The general reduction of microdeficiency in rubberized fabrics in comparison with initial rubber is revealed and rationalized
177 kb

RESEARCH OF PHASE BALANCES LIQUID-SOLID OF TERNARY ALLOY MATERIALS OF LOW-MELT METALS BY CALCULATING METHOD

abstract 0350801008 issue 35 pp. 76 – 90 29.01.2008 ru 3773
Article is devoted to the research and working out of calculation method of thermodynamic data and phase diagrams of ternary alloy materials of low-melt metals with the use of data bases known in literature.
242 kb

RESEARCH OF PHASE BALANCES OF LIQUID-SOLID PENTONARY ALLOY MATERIALS OF LOW-MELT METALS WITH CALCULATING METHOD

abstract 0821208035 issue 82 pp. 449 – 458 31.10.2012 ru 1475
The article is devoted to the research and working out of calculation method of thermodynamic data and phase diagrams of pentonary alloy materials of low-melt
129 kb

RESEARCH OF PHASE-TRANSITIVE MATERIALS BY THE EXPERIMENTAL METHODS

abstract 0420808007 issue 42 pp. 128 – 138 14.10.2008 ru 2748
The article is devoted to the application of method of differential-scanning microcalorimetry for research of phase-transitive materials on the base of inorganic and organic substances.
297 kb

STRUCTURE OF SPACE CHARGE REGION AT BIPOLAR JUNCTION AND DISSOCIATION OF WATER MOLECULES IN BIPOLAR MEMBRANE MODIFIED BY CHROMIUM(III) COMPOUND

abstract 1041410075 issue 104 pp. 995 – 1014 30.12.2014 ru 992
In the article the mathematical model of the space charge region in the bipolar membrane is considered. The structure of the space charge region under passing of electric current, and without electric current is discussed. The results of experimental studies of water dissociation in the bipolar membrane in the presence of chromium(III) are discussed
239 kb

STUDY OF EARLY STAGES OF MELANOIDIN’S FORMATION PROCESSES IN MODEL ETHANOLIC D-GLUCOSE – pTOLUIDINE SYSTEM

abstract 1321708057 issue 132 pp. 720 – 727 31.10.2017 ru 467
The results of investigation of melanoidin’s formation early stages in acidic ethanolic D-glucose – p-toluidine model system are presented. Based on the elemental analysis, IR- and UV-spectroscopy data obtained we have shown, that in system studied Amadori rearrangement product undergo the aryl amine elimination during browning to form a nonnitrogenous reductons with antioxidative activity in processes of linoleic acid oxidation. It is also noted, that in system studied inhibition of carbohydrate’s destruction occurs because of non-reactive O-ethylglycosides formation. The data obtained may be useful for technology of carbohydrate-containing raw material
483 kb

STUDY OF THE INTERACTION OF POLYSTYRENE-AZO-O-PHENOL-AZO-RHODANINE WITH ZINC IONS AND CADMIUM

abstract 1181604067 issue 118 pp. 1086 – 1096 29.04.2016 ru 635
Since the industrial revolution a huge amount of pollutants emitted annually into the water most of which is occupied by toxic metals. These metals widely distributed in the environment and of accumulation of a threat to human health. It is known, that cadmium and zinc at high concentrations have a negative impact on nature. In modern wastewater treatment technology we widely use polymeric sorbents with chelating properties. The use of polymeric chelating sorbents (PCS) usage allows separating individual or group trace elements from large volumes of solutions of complex composition, lowering the limit of detection, eliminating or reducing significantly the impact of macrocomponents which increases the cleaning efficiency. The article presents the results of a study of conditions of interaction of zinc (II) ions and cadmium (II) with PCT - polystyrene-azo-o-phenol-azo-rhodanine. We found the optimal values of the conditions for zinc (II) ions and cadmium (II) sorption. We investigated the effect of interfering of the macro- and micro- water components with the sorption of the ions studied. Maximum desorption of metal ions is achieved by washing the concentrate with 10 ml of 2M hydrochloric acid. The data indicate availability of the investigated sorbent for concentration and separation of zinc (II) ions and cadmium (II)
134 kb

SURFACE ENERGY OF POLYMERS (ELASTOMER COMPOSITIONS): A COMPARATIVE ANALYSIS OF THE VALUES OF SURFACE ENERGY PARAMETERS OF DEFECTS IN POLYMERS

abstract 1311707029 issue 131 pp. 301 – 310 29.09.2017 ru 751
Surface energy of polymers determines such important properties of polymers like wetability, adhesion, ability adsorption of low molecular weight substances. Inner organization, the structure of the polymer and the dynamics of interaction between macromolecular chains are shown at last. At the same time, the micro-defects (inhomogeneity) of polymers, which is an integral part of the structure are changed during deformation and must contribute to changing of the surface energy and its components. This article solves the task of detecting changes in the parameters of surface energy of polymers under uniaxial deformation. Data for the quantitative indicators of the surface properties total surface energy and its dispersive and polar components are presented. The calculations showed that the disperse and polar components of all the samples of polymer materials are about 98% of the total and, therefore, is crucial. For the first time experimental data, illustrating the change of surface energy of polymeric materials had been obtained, including elastomeric compositions, when uniaxial deformation. The relative changes of the surface energy vary from 54.5 per cent to 125 %. A decrease of total surface energy and its dispersion component is observed during deformation of polymer samples of different structure and chemical nature
.