111 research outputs found
Numerical modelling of two-phase piezocomposites with interface mechanical anisotropic effects
This work was supported by the Russian Science Foundation (grant № 15-19-10008-P)
Comparative analysis of spherical focusing transducers from dense and porous piezoceramic materials
The second author is grateful for the support of the Ministry of Education and Science of the Russian Federation, project 9.1001.2017/4.6
The banding in serpentinites and its influence on character of talc-magnesite and magnesite mineralization (natural and experimental data)
The geological setting of some banded talc-magnesite ores and magnesites was studied in the
field (Urals, Russia; Finland, East Iran). Talc-magnesite and magnesite ores occur in ultramafic
rocks. Experimental methods were used in order to determine the influence of physico-mechanical
parameters on the formation of banded structures in talc-magnesite rocks and magnesites.
Experiments were carried out with axial compression up to 10 kbar and confining pressure 2, 4, 6
and 8 kbars at room temperature.
The samples were chemically analyzed using a Philips Analytical PW 2400 authomatic XRF
Spectrometer and a scanning electron microscope (SEM).
Some analyses were made with a "Camebax SX-50" electron microprobe, using an accelerating
voltage of 20 kilovolts for all elements with a sample current of 20 nanoamps. X-ray method for
phase identification was used. Structure peculiarities of rocks prior to the experiment and after
were studied by optical methods in polished sections and thin sections.
It was shown, that banding in talc-magnesite stone and magnesites are inherited from banded
serpentinites and can affect on distribution and composition rock-forming minerals
The behaviours of Mg and Ca in some types of ultramaphic alkaline melts in the presence of H 2 O at high temperature and pressure (the experimental data)
The sample has been investigated, which was composed of olivine-melilite rock from the
south-western part of the Kugda intrusion, situated in the eastern margin of the Maimecha-Kotuiskay
alkaline- ultramaphic province (northern part of Siberia platform). The experiments were carried
out using a high-pressure apparatus of the "piston-cylinder" type. The pressure was 5-15 kb and
the temperature -800-1250 0 C. The water content in the system was 3 and 9 wt. All experiments
were carried out in hermetically sealed Pt or Au ampoules. The samples were chemically analyzed
using a scanning electron microscope (SEM). Besides, the chemical composition of the experimental
phases was determined by means of more than 40 electron microprobe in 20 experimental samples.
For phase identification the X-ray method was used too. The structural peculiarities of rocks and
mineral compositions were studied by optical methods in polished and thin sections prior and
after the experiment. It was shown that at pressures above 7.5-8 kb the olivine-melilite melt is
separated into two melts: pyroxenite and melilite. Most part of Mg in this system was concentrated
in a high temperature phase of diopside type. The remaining melt was depleted of Mg and enriched
by Ca. The mineralization vapour practically did not contain Mg. The main components of the
mineralization vapour were Ca, Na, Si and Fe
Finite element modeling of effective properties of nanoporous thermoelastic composites with surface effects
This investigation concerns to the determination of the material properties
of nanoscale thermoelastic composites of an arbitrary anisotropy class with stochastically
distributed porosity. In order to take into account nanoscale level at the borders between
material and pores, the GurtinMurdoch model of surface stresses and the highly conduct- ing model
are used. Finite element package ANSYS was used to simulate representative volume and to calculate
the effective material properties. This approach is based on the theory of effective moduli of
composite mechanics, modeling of representative volumes and the finite element method. Here,
the contact boundaries between material and pores were covered by the surface membrane elastic and
thermal shell elements in order to take
the surface effects into account
Finite element modelling of 1-3 piezoelectric polymer composites with surface effects
This work for second author was supported by the Russian Science Foundation (grant number 15-19-10008-P)
Analysis of porosity influence on the effective moduli of ceramic matrix PZT composite based on the simplified finite element model
The work was carried out as part of project No. 9.1001.2017 / 4.6 of the competitive part of the state task of the Ministry of Science and Higher Education of Russia
Exoplanet Imaging Data Challenge, phase II: Characterization of exoplanet signals in high-contrast images
Today, there exists a wide variety of algorithms dedicated to high-contrast
imaging, especially for the detection and characterisation of exoplanet
signals. These algorithms are tailored to address the very high contrast
between the exoplanet signal(s), which can be more than two orders of magnitude
fainter than the bright starlight residuals in coronagraphic images. The
starlight residuals are inhomogeneously distributed and follow various
timescales that depend on the observing conditions and on the target star
brightness. Disentangling the exoplanet signals within the starlight residuals
is therefore challenging, and new post-processing algorithms are striving to
achieve more accurate astrophysical results. The Exoplanet Imaging Data
Challenge is a community-wide effort to develop, compare and evaluate
algorithms using a set of benchmark high-contrast imaging datasets. After a
first phase ran in 2020 and focused on the detection capabilities of existing
algorithms, the focus of this ongoing second phase is to compare the
characterisation capabilities of state-of-the-art techniques. The
characterisation of planetary companions is two-fold: the astrometry (estimated
position with respect to the host star) and spectrophotometry (estimated
contrast with respect to the host star, as a function of wavelength). The goal
of this second phase is to offer a platform for the community to benchmark
techniques in a fair, homogeneous and robust way, and to foster collaborations.Comment: Submitted to SPIE Astronomical Telescopes + Instrumentation 2022,
Adaptive Optics Systems VIII, Paper 12185-
Surgical Treatment of Decompensated Cicatricial Stricture of the Esophagus, Grade III-IV Dysphagia, and Compression Syndrome Caused by Nontoxic Multinodular Goiter: A Case Report
Objective: Long-standing gastroesophageal reflux disease is the most common cause of a cicatricial stricture of the esophagus. The treatment of this pathology involves a wide range of methods including conservative and surgical options. Surgeons can encounter technical difficulties in case of concomitant neck and chest pathology.Clinical case: We report a case of a decompensated cicatricial stricture of the esophagus with concomitant paraesophageal hiatal hernia, refractory gastroesophageal reflux disease, and nontoxic multinodular goiter (166.9 cm3). Selecting the optimal management for such patients is often a challenge. Staged treatment significantly improves postoperative quality of life, but the increased length of hospital stay can negatively impact patient compliance
A case report of surgical treatment of amiodarone-induced thyrotoxicosis in a patient with multiple organ failure
Amiodarone is a drug used in the treatment of life-threatening arrhythmias, which can lead to the development of amiodarone-induced thyrotoxicosis. In most cases this pathology can be treated by conservative methods; surgical treatment is resorted to in cases of thyrotoxicosis refractory to medical treatment. This case report describes surgical treatment of a patient with amiodarone-induced thyrotoxicosis, progressive heart failure, neurological pathology, bilateral pneumonia, functioning tracheostomy, systemic infectious process, multiple organ dysfunction syndrome, who was treated in the intensive care unit. Due to the lack of response to therapy with antithyroid drugs (thiamazole, lithium preparations and pulse therapy with prednisolone) and a progressive deterioration of the condition in a short period of time, according to vital indicators, the patient underwent thyroidectomy. In the postoperative period, there was a decrease in the occurrence of chronic heart failure symptoms. Medical control of cardiac arrhythmias was achieved. Surgical stage proceeded without complications in the period of 30-days. The patient was discharged for outpatient rehabilitation treatment
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