LOW-FREQUENCY PULSE DIELECTRIC SPECTROMETER.

Apparatus is described for study of dispersion of the dielectric constants of low-conducting dielectrics in the time range of 5. 10** minus **7-3. 10**2 sec. The charge response of a measuring capacitor to a voltage discontinuity is recorded in a logarithmic time scale

Calculation of resonances in the Coulomb three-body system with two disintegration channels in the adiabatic hyperspherical approach

The method of calculation of the resonance characteristics is developed for the metastable states of the Coulomb three-body (CTB) system with two disintegration channels. The energy dependence of K-matrix in the resonance region is calculated with the use of the stabilization method. Resonance position and partial widths are obtained by fitting the numerically calculated K(E)-matrix with the help of the generalized Breit-Wigner formula.Comment: Latex, 11 pages with 5 figures and 2 table

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

Water structure analysis considering dielectric spectrum in microwave range

In this paper the analysis of the water dielectric spectrum in the relaxation (1 cm) and microwave (100 mu) range on the basis of the theoretical results presented in Ref. was made. The absorption spectrum in the microwave range as well as the relaxation spectrum are shown to be the results of the orientational polarization. In the framework of the existing water structure models this result corresponds to the models in which one assume two types of the molecules for the fixed time moment. They are the molecules having a hydrogen bonds and ones free from them. Free molecules either can be located in the voids or can make the exchange between the clasters. In the analysis suggested we do not use the definite water structure model. The dielectric spectrum parameters allow us estimate the value of the abnormal water expansion within the freezing process. Our results agree well with the experimental data

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

Large-basin hydrological response to climate model outputs: uncertainty caused by internal atmospheric variability

An approach is proposed to assess hydrological simulation uncertainty originating from internal atmospheric variability. The latter is one of three major factors contributing to uncertainty of simulated climate change projections (along with so-called "forcing" and "climate model" uncertainties). Importantly, the role of internal atmospheric variability is most visible over spatio-temporal scales of water management in large river basins. Internal atmospheric variability is represented by large ensemble simulations (45 members) with the ECHAM5 atmospheric general circulation model. Ensemble simulations are performed using identical prescribed lower boundary conditions (observed sea surface temperature, SST, and sea ice concentration, SIC, for 1979–2012) and constant external forcing parameters but different initial conditions of the atmosphere. The ensemble of bias-corrected ECHAM5 outputs and ensemble averaged ECHAM5 output are used as a distributed input for the ECOMAG and SWAP hydrological models. The corresponding ensembles of runoff hydrographs are calculated for two large rivers of the Arctic basin: the Lena and Northern Dvina rivers. A number of runoff statistics including the mean and the standard deviation of annual, monthly and daily runoff, as well as annual runoff trend, are assessed. Uncertainties of runoff statistics caused by internal atmospheric variability are estimated. It is found that uncertainty of the mean and the standard deviation of runoff has a significant seasonal dependence on the maximum during the periods of spring–summer snowmelt and summer–autumn rainfall floods. Noticeable nonlinearity of the hydrological models' results in the ensemble ECHAM5 output is found most strongly expressed for the Northern Dvina River basin. It is shown that the averaging over ensemble members effectively filters the stochastic term related to internal atmospheric variability. Simulated discharge trends are close to normally distributed around the ensemble mean value, which fits well to empirical estimates and, for the Lena River, indicates that a considerable portion of the observed trend can be externally driven

Correlation effects during liquid infiltration into hydrophobic nanoporous mediums

Correlation effects arising during liquid infiltration into hydrophobic porous medium are considered. On the basis of these effects a mechanism of energy absorption at filling porous medium by nonwetting liquid is suggested. In accordance with this mechanism, the absorption of mechanical energy is a result expenditure of energy for the formation of menisci in the pores on the shell of the infinite cluster and expenditure of energy for the formation of liquid-porous medium interface in the pores belonging to the infinite cluster of filled pores. It was found that in dependences on the porosity and, consequently, in dependences on the number of filled pores neighbors, the thermal effect of filling can be either positive or negative and the cycle of infiltration-defiltration can be closed with full outflow of liquid. It can occur under certain relation between percolation properties of porous medium and the energy characteristics of the liquid-porous medium interface and the liquid-gas interface. It is shown that a consecutive account of these correlation effects and percolation properties of the pores space during infiltration allow to describe all experimental data under discussion

Integral estimation of systemic inflammatory response under sepsis

Currently, the most significant mediators of the systemic inflammatory response (SIR), specific to the development of critical states in sepsis, have the chaotic changes of concentrations in the blood. The solution to the problem is using integral indicators. A scoring scale of the SIR (0–16 points) is proposed based on the determination in the blood plasma of CRP, TNF-α, IL-6, IL-8 and IL-10. The scale was used in the survey of 167 patients with a diagnosis of sepsis (43 patients with sepsis according to definitions of “Sepsis-1 or 2” and 124 patients with sepsis according to the criteria of “Sepsis-3”); septic shock was verified in 31 cases and in 48 cases lethal outcomes were recorded. The association of SIR with critical complications of sepsis was revealed, especially under acute septic shock and in cases of a “second wave” (days 5–7) of critical complications. In contrast, prolonged/ subacute sepsis (more than 14 days) under tertiary peritonitis is characterised by a lesser dependence of the criticality of the state on the severity of SIR. The proposed scale is an open system and allows you to modify the range of used particular indicators that are compatible by pathogenetic and diagnostic significance. © 2020, Slovak Academy of Sciences. All rights reserved.The work was carried out within the framework of the IIP UrB RAS theme No АААА-А18-118020590108-7