Differences in behaviour of adsorbed water in kaolinites and montmorillonites in temperature range from -90°C to +140°C by dielectric spectroscopy

Two different types of natural layer aluminosilicates (clay minerals), montmorillonite with the exchangeable K+ and Ni2+ cations and kaolinite with the exchangeable K+ and Ba2+ cations, were investigated by dielectric spectroscopy. The different effects of water adsorption in montmorillonites and kaolinites on the dielectric response were observed in wide temperature (-90°C ÷ +140°C) and frequency (1 Hz ÷ 1 MHz) ranges. The influence of the nature of the hydration centers on adsorbed water dynamics and influence of ions nature on the activation energy values of the relaxation processes were discussed

Two types of adsorbed water in natural montmorillonites at low temperatures by dielectric spectroscopy

Dielectric spectroscopy was applied to natural clay mineral - montmorillonite with the exchangeable K+ and Ni2+ cations where the effect of water adsorption in the samples on the dielectric response was examined in the temperature from -115°C to -75°C and frequency from 1 Hz to 1 MHz ranges. Two relaxation processes (1 and 2) were revealed. The process 1 was related to the adsorbed ordered water structures formed on the interior surface of interlayer channels while the relaxation process 2 was attributed to the disordered water structures built between two surface water monolayers

The percolation phenomenon and fractal dimension of natural silicates

© (2015) Trans Tech Publications, Switzerland. Many physical effects, such as dc conductivity and percolation, depend on the morphology of the silicate structure and its relationship to adsorbed water. These effects play an important role in numerous technological applications, in geology, oil-extracting industry, and other practical fields. In this study, all the samples: natural montmorillonite, kaolinite, and ?linoptilolite with different exchangeable cations in their structures, - were stored in ambient air humidity. The investigation was carried by using two separate techniques, namely Dielectric Spectroscopy and a fractal analysis of electron micrographs. The aims of this work were to analyze the complex relaxation behavior of the relaxation process in temperature range -70°C ÷ 70°C and to determine the fractal dimensions of silicates from the dielectric response at percolation. Dielectric measurements in the frequency range of 1 Hz ÷ 1 MHz were performed using a BDS 80 Dielectric Spectrometer based on an Alpha Impedance Analyzer (Novocontrol). The micrographs were analyzed using a special Matlab based program. The analysis of aspects of the dielectric relaxation spectra related to percolation was used for the determination of the numerical characteristics of geometric heterogeneity of natural silicates. The percolation temperatures of the studied samples were determined. The percolation phenomenon in the silicates is related to the transfer of the electric excitation within the developed network of open pores due to the migration of protons and ions along the surface of connected pores on the outer surfaces of the granules. The analysis of these processes allows one to extract the fractal dimensions associated with the migration of charge carriers within the porous medium. Fractal dimensions of the silicates calculated in two ways: from dielectric spectroscopy study and from fractal analysis of the micrographs, - are in good agreement with each other. It was demonstrated that conventional method of the spatial fractal dimension determination using fractal analysis of electron micrographs leads to overestimation in the case of spatial fractal bounded by a surface fractal. The dielectric spectroscopy method is free from such overestimation

Problems of Higher School Didactics: Uncut Pages

Higher education today is not going through the best of times: decisions taken in the educational process at various levels (Federal Laws “On Education in the Russian Federation” of 29.12.2012 No 273-FZ and “On Amendments to the Federal Law “On Education in the Russian Federation” on the education of students” of 31.07.2020 No 304-FZ, Federal State Educational Standards of Higher Education, etc.), related to global changes taking place in society and in the world in recent decades, were made without careful didactic study. This cannot help to improve the quality of specialist training. Teachers are forced to work “by trial and error”, producing countless didactic documents. At present, identification of didactic problems in the educational process of higher educational institutions is extremely relevant due to the expansion of the field of didactic research in higher school pedagogy.The aim of the authors was to analyze some of the most relevant didactic phenomena in the digital reality that have not yet received proper understanding. As a result of the analysis, some important didactic problems of higher education are identified, concerning goal-setting, compliance of teaching with classical didactic principles, organization of distance learning in electronic informational and educational environment, mixed and project-based learning. The article also dwells on psychological problems of Internet content assimilation and “non-contact” interaction between the subjects of the educational process, etc. The most promising areas of didactic research in higher education, including the development of interdisciplinary contacts, are highlighted

Epidemiological features of chickenpox among children

The aim of the study - to identify the epidemiological features of the incidence of chickenpox among the child population in the territory of the Moscow Region of Yekaterinburg and to determine ways to optimize epidemiological surveillanceЦель исследования – выявить эпидемиологические особенности заболеваемости ветряной оспой среди детского населения на территории МО г. Екатеринбург и определить пути оптимизации эпидемиологического надзор

The study of the educational process with the use of electronic learning tools for schoolchildren of grades 6 – 8

The purpose of the study is to study the educational process with the use of ESO in the school N. and recommendations for optimizing the educational process in order to prevent fatigue.Цель исследования – изучение образовательного процесса с применением ЭСО в МБОУ СОШ г. N. и рекомендации по оптимизации учебного процесса с целью профилактики утомления

Dielectric relaxation of water in clay minerals

The study of confined water dynamics in clay minerals is a very important topic in aluminosilicate-surface chemistry. Aluminosilicates are among the most technologically versatile materials in industry today. Dielectric spectroscopy is a very useful method for investigating the structure and dynamics of water adsorbed on solid matrix surfaces and water in the vicinity of ions in solutions. Use of this method for the study of clay minerals has been underutilized to date, however. The main goal of the present research was to understand the relaxation mechanisms of water molecules interacting with different hydration centers in clay minerals, with a view to eventually control this interaction. Two types of natural layered aluminosilicates (clay minerals) montmorillonite with exchangeable K+, Co2+, and Ni2+ cations and kaolinite with exchangeable K+ and Ba2+ cations were examined by means of dielectric spectroscopy over wide ranges of temperature (from -121°C to +300°C) and frequency (1 Hz-1 MHz). An analysis of the experimental data is provided in terms of four distributed relaxation processes. The low-temperature relaxation was observed only in montmorillonites and could be subdivided into two processes, each related to a specific hydration center. The cooperative behavior of water at the interface was observed in the intermediate temperature region, together with a proton percolation. The dielectric properties of ice-like and confined water structures in the layered clay minerals were compared with the dielectric response observed in porous glasses. The spatial fractal dimensions of the porous aluminosilicates were calculated by two separate methods - from an analysis of the fractality found in photomicrographs and from the dielectric response

Initial stage of formation of spontaneous invasive populations of garden lupine (lupinus polyphyllus lindl.) at the northern limit of its secondary distribution range in the veps forest nature park

A weed plant of the species Lupinus polyphyllus was found in settlements located on the territory of the natural park «Vepssky forest» of the Leningrad regio

THE USE OF COMPRESSED GASES IN THE CONVERTER TECHNOLOGY FOR THE RECOVERY OF PELLETS

The article describes the way to effectively use the regenerative properties of Converter gas. A calculation presented of the necessary shares on the compression process “Midrex” recovery of pellets.В статье рассмотрен способ эффективного использования восстановительных свойств конвертерного газа. Представлен расчет необходимой доли газов, направляемых на сжатие для процесса «Мидрекс» по восстановлению окатышей