bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Hydrophobic Silica Nanopowders
Authors: Bardakhanov Sergey , Zavialov Alexey , Lygdenov Valeriy , Lysenko Vladimir , Skiba Sergey , Nomoev Andrey , Manakov Andrey , Syzrantsev Vyacheslav , Romanov Nikolay , Kalashnikov Sergey , Trufanov Dmitriy
Published: December 2021

The technique of receiving of nano-silica nanopowders, consisting of nanoparticles with the known size, form, internal and surface structure and physicochemical properties was developed. The degree of hydrophilicity of those powders was determined. The method of the surface modification (hydrophobization) of the received nanoparticles was carried out and was optimized. Replacement of surface OH-groups on the CH3-group was produced by blowing SiCl2(CH3)2 vapor over the modified powders surface. The carbon content of the modified powders reached 3.2 %. The comparison of the hydrophobization process for the nanopowders received by two different origins was carried out. It was shown that the surface modification of Aerosil powders is faster than Tarkosil ones at similar hydrophilicity degree. Also hydrophobiс Aerosil contains more amount of carbon was cleared (up to 5,9 %). The complete replacement of OH-groups on the organic groups on the surface of powders was showed by IR spectroscopy. The representation of the organic groups by several combinations of fragments, rather than just the CH3 was showed
Synthesis and Properties of Ceramics from Ferric Oxide Nanopowder
Authors: Lysenko Vladimir , Gorev Vasily , Litvinenko Yuriy , Bardakhanov Sergey
Published: December 2021

Possibilities of receiving ceramics from the nanodisperse ferric oxide (II, III) powder are investigated. In a hot pressing facility (by Spark Plasma Sintering method) the ceramics with fine-grained (about 1 micron and less) structure made. Structure of the received ceramics is investigated by the method of scanning electronic microscopy. Radiographic examination of initial nanopowder and the received ceramics is also carried out. If in the phase relation the initial powder and the ceramics sintered at 800 о С are magnetite Fe3O4 (75-1610), the ceramics sintered at 900 о С – Fe3O4 (75-33), and at 1200о С the diffraction picture of a mixture of two phases – a iron protoxide FeO (46-1312) phase and a metal Fe (6-696) phase – took place. Microhardness of the ceramics was 8 GPa, ultimate compression strength – 0,8 GPa. Thereby availability of use of the SPS method is shown
Theoretical Study of Collective Vibration Amplitude Properties of Amorphous Ices
Authors: Gets Kirill , Subbotin Oleg
Published: December 2021

Model structures of low (LDA), high (HDA) and very high (VHDA) density amorphous ices were obtained using the Molecular Dynamics method (MD). Radial distribution function and function of vibrational density of states calculated through the lattice dynamics method are in good agreement with experimental data. The existence of collective vibrations taking part in amorphous ices was confirmed. It was shown that the amplitudes of localized vibrations are more than ten times higher than amplitudes of delocalized vibrations. Molecular distribution on the amplitude of translational and libration vibrations and molecular distribution on the values of potential energy represented the similarity of the amorphous ices properties to crystal ones
Wave Packet Excitation and its Development in Supersonic Boundary Layer
Authors: Yatskih Alex , Yermolaev Yuri , Kosinov Aleksandr , Semionov Nikolay
Published: December 2021

A method of exciting of artificial disturbances localized in space and time (wave packets) in a supersonic boundary layer is developed. Experimental investigations are carried out in the low noise supersonic wind tunnel T-325 at Mach M = 2. A model of a flat steel plate with a sharp leading edge is used. Measurements of mean flow and fluctuations are performed by using a constant temperature anemometer. To generate controlled fluctuations the short time surface glow discharge is used. Measurements of controlled disturbances are synchronized in time with glow discharge ignition. To increase the signal-to-noise ratio the time trace averaging technique is applied. Electrical power and polarity of the glow discharge initiation are changed to see their influence on the initial wave packet amplitude. Optimal glow discharge parameters for generation of artificial disturbances are found. The experimental data on the localized disturbances evolution in boundary layer are received. It is obtained that the velocity of the wave packet propagation has speed close to the free stream for the leading wave edge. The trailing edge of the wave packet spreads with subsonic speed relatively the supersonic flow. The wave packet propagates in both the streamwise and spanwise directions. Half-angle of this spreading is approximately equal to 10 degrees relative to the free stream direction. It has been found, that the wave packet is developed inside the boundary layer near of the artificial pulsations source. However the evolution of controlled disturbances leads to their radiation into free flow
Proposal for Two-Phase Cryogenic Avalanche Detector for Dark Matter Search and Low-Energy Neutrino Detection
Authors: Bondar Aleksandr , Buzulutskov Alexey , Dolgov Aleksandr , Peleganchuk Sergey , Snopkov Rostislav , Sokolov Andrey , Shemyakina Ekaterina , Shekhtman Lev
Published: December 2021

The proposal for the detector of ultimate sensitivity for Dark Matter search and low-energy neutrino detection, including that of coherent neutrino-nucleus scattering, is presented, based on the technique of two-phase Cryogenic Avalanche Detectors (CRADs) in Ar. Such a detector, with a 160 l cryogenic chamber, will be able to operate in single electron counting mode with superior (~ 1 mm) spatial resolution. To obtain such characteristics, a novel technique to detect ionization signal is applied, namely an optical readout using combined multiplier comprising of Gas Electron Multipliers (GEMs) and a matrix of Geiger-mode APDs (GAPDs)
Kinematic Model of Mobile-Cylinder Engine of Cyclic Design
Authors: Fedorenko Stanislav , Nikiforov Alexey , Fedorov Vladimir
Published: December 2021

A kinematic model of mobile-cylinder engine of cyclic design is suggested. Analysis of motion equation solutions reveals periodic pulsations of rotational frequency in the system which leads to non-uniform rotation of a crank shaft. The amplitude and pulsation phase depend essentially on geometric and kinematic parameters of the model. Possible ways of the model optimization such as to damp the amplitude of rotational frequency pulsations are discussed
Formalism «Magneto Cross-Sections» of D– (A+ )-Centers at Resonance Scattering of Charged Carriers in Angenerated Semiconductors
Authors: Muratov Temur
Published: December 2021

The new approach to study of kinetic effects in covalent semiconductors is developed. On example of the calculation kinetic coefficients at resonance scattering some particularities of the proposed approach are demonstrated. Influence of limited weak magnetic field on kinetic effects is studied. Unlike standard method, taking into account presence of the H-field in the nonequilibrium distribution function with the following reception sought formulas for kinetic coefficients, in proposed approach presence (the influence) of the weak H-field is fixed as local (virtual) incrementation of crosssection of the concrete scattering, in this given case it’s resonance. Formal change   res eff 0 H    allows relatively easy to analyze the influence of the H-field on kinetic effects. It is shown that at presence of the H-field electronic conductivity reached the maximum near 1 K in the range of fields of the order 100 Gauss. General result is revealed in process of the calculation at any mechanism of the scattering. The main requirement is that the low-temperature asymptotics T 0 l  of concrete mechanism of the scattering should be constant
Technology of the Solution of Tasks of Thermodynamics and Molecular Physics
Authors: Zamuraev Vladimir , Kalinina Anna
Published: December 2021

Now tasks which are more difficult, than school, are characterized with a small number of methodical approaches. In this work elements of technology of the solution of tasks of thermodynamics and molecular physics are presented. Besides, in work some techniques which should be used competently at the some tasks solution, and also algorithms for the solution of classes of tasks with concrete examples of their realization are offered
Fast High Resolution Position-Sensitive Gaseous Detectors
Authors: Shekhtman Lev , Dolgov Aleksandr
Published: December 2021

The present review describes a new coordinate detectors based on gas micro-pattern technology, which are applied in experiments in elementary particle physics and with SR beams. The microstrip gas chambers (MSGC) on substrates with electronic conductivity are presented in the paper. Such detectors are shown to have spatial resolution better than 100 micron and to be able to effectively operate at particle rates up to 106 s-1mm-2, that at least by two orders of magnitude higher than rate capability of multiwire proportional chambers. Essential part of the review is devoted to studies of the cascades of gas electron multipliers (GEM). In particular, the dependence of gas amplification and conditions of a discharge occurrence on the number of GEMs in cascade, on the distribution of potentials between GEMs in cascade and on gas mixture in the presence of hadron flux are discussed. Gas micro-pattern technology is widely used for the development of coordinate detectors. In the present review we describe as an example the detectors with triple GEM cascades for the tagging system of the KEDR experiment at the VEPP-4M collider
Electron Accelerator ELV-4 Energy Ripples
Authors: Bryazgin Konstantin , Domarov Evgeniy , Korchagin Aleksey , Kuksanov Nikolay , Nemytov Petr , Salimov Rustam , Fadeev Sergey
Published: December 2021

This article deals with modernization of industrial electron accelerator ELV-4 with parameters 1 MeV, 100 mA. The goal of upgrading was to decrease accelerating voltage ripples to ± 5 %. The experiments were performed on a simplified accelerator for tomography. Special sensor was created to measure energy ripples. Calibration of sensor has been done in two ways. Energy ripples signal spectrum was obtained. The main components have been studied
Experimental Investigation of Instantaneous and Mean Flow Characteristics Behind the Rotor Model of Wind Turbine
Authors: Kabardin Ivan , Naumov Igor , Mikkelsen Robert , Pavlov Vladimir , Bakakin Grigory , Okulov Valeriy
Published: December 2021

This work sufficiently appends and extends experimental investigation of flow structure downstream of the triblade turbine model, which was started in 2011. Shadow zones from blades were removed and a measuring zone was increased as a result of changing in optical system of PIV. These changes made possible to carry out measurements in much more far zone downstream the rotor model. As a result new features of flow were found out in near and far wake downstream the turbine. The estimation of turbine work efficiency on different work regimes was carried out due to tensometric measurements of rotor force characteristics. This data corresponds to assumptions and hypothesis of classical theories of rotors and to a form for the optimum blades designed by the BEM method
Experimental Investigation of a Free Round Jet with Dean Vortices
Authors: Litvinenko Maria , Litvinenko Yuriy , Kozlov Grigory , Vikhorev Valentin
Published: December 2021

Results of the experimental investigations of free round jet with Dean vortices formed in curved channel are presented. Hot-wire anemometry measurements of three-dimensional mean velocity profile were performed, smoke visualization pictures cross and longitudinal sections at nozzle exit and downstream were obtained. The features of jet development at acoustic excitation of 40 Hz are shown
The Temperature of Berezinsky – Kosterlitz – Thouless Transition in Two-Dimensional Superconductor in an External Field
Authors: Krinitsyn Aleksandr , Tikhomirov Iliya , Yugay Klimentiy
Published: December 2021

The Method of Monte-Carlo calculated temperature of Berezinsky – Kosterlitz – Thouless transition in twodimensional superconductor 2nd type in the presence of an external magnetic field. It is shown that near the upper critical field filling cells with a size of ξ × ξ relation, where ξ – coherence length at a given temperature, corresponds to half. It is also shown that ТBKT decreases with increasing interaction between the vortices and antivortices and increase of the external applied magnetic field
Folding Of Trp-Cage Protein In Equilibrium And Nonequilibrium Conditions: Molecular Dynamics Simulations
Authors: Andryushchenko Vladimir , Chekmarev Sergey
Published: December 2021

The study of the dynamics of protein folding into its functional (native) state is one of the actual problems of molecular biology. For this, molecular dynamics simulations are widely used. The conditions under which the simulations are performed are important for the correct description of the folding process. In the present paper, we study the folding dynamics of one of the benchmark proteins (Trp-cage) under two conditions – the equilibrium conditions, when the protein repeatedly folds and unfolds, and under nonequilibrium conditions, when an ensemble of trajectories is generated that start in an unfolded sate of the protein and are terminated in the native state, which corresponds to the physiological conditions. It is shown that the behavior of the protein under these conditions is essentially different; in particular, in the case of nonequilibrium conditions an additional metastable state is formed, which leads to a separate folding pathway. The simulations have also shown that the kinetics of Trp-cage are two-state, which corresponds to the experimental results.
Electromagnetic Optimization Of Ultra-Thin Resonant Absorbers For Bolometric Detectors Of The Submillimeter-Wave Range
Authors: Kuznetsov Sergei , Arzhannikov Andrey
Published: December 2021

We present the results of theoretical analysis and characteristics optimization for ultra-thin resonant absorbers based on artificial impedance surfaces, which are promising for using as the radiation-sensitive layers in selective bolometric detectors operating in the range of submillimeter waves. The key parameters of the ultra-thin absorbers, such as the absorption resonance Q-factor, the ratio of the peak absorptivity wavelength to the absorber thickness and the impedance surface unit cell size, are traced versus a geometric shape of the resonant elements and their electrical conductivity.
Epr Spectroscopy Of Trityl Radicals: Specificities Of Hyperfine Interaction Of An Unpaired Electron With 13c Nuclei
Authors: Strizhakov Rodion , Kuzhelev Andrey , Tormyshev Viktor , Bagryanskaya Elena
Published: December 2021

The constants of hyperfine coupling between an unpaired electron and natural occurrence 13C have been registered for the representative series of trityl radicals. The analysis of hyperfine ac constantsrevealed their small if any dependence both on solvent, and origin and number of substituents attached at para-C atoms of TAM aromatic rings.
Influence Of Vortex Disturbances On Laminar-Turbulent Transition In Supersonic Boundary Layer On A Swept Wing At M = 2.5
Authors: Dryasov Andrey , Yermolaev Yuri , Kosinov Aleksandr , Semionov Nikolay , Semionov Aleksandr
Published: December 2021

Experimental investigations of the receptivity of a supersonic boundary layer on a swept wing to the vortex perturbations were made at Mach 2.5. A symmetrical wing model with a 45 sweep angle and a 3-percent-thick circular-arc airfoil was used in experiments. The investigation of the vortex disturbances structure generated by a wire was done. It has been shown that the level of disturbances in the free flow increases with increasing wire diameter. The positions of the laminarturbulent transition at different diameters of wire were determined and data of the disturbances development in the model boundary layer were obtained. It was found that an increase in the intensity of vortex disturbances in the free flow leads to an earlier transition. Receptivity coefficients were determined.
Sensitivity To Disorder Of Graphene-Like Lattices Of Quantum Dots And Antidots In Two-Dimensional Electron Gas
Authors: Tkachenko Olga , Tkachenko Vitaliy
Published: December 2021

We compare three-dimensional electrostatics of semiconductor structures with graphene-like lattices of quantum dots and antidots formed in the plane of the two dimensional electron gas. With lattice constant fixed, the shape of the potential may be tuned so that both lattices have minband spectrum where the second Dirac feature is pronounced and not overlaid by the other states. We show that the lattice of quantum dots is more sensitive to fabrication imperfections, because sources of the disorder are located directly above the electronic channels. Thus the lattices of antidots should be preferred semiconductor artificial graphene candidates.
Formation Of Two-Dimensional Photonic Crystals With Cavities Arrays In Silicon
Authors: Utkin Dmitriy , Shklyaev Aleksandr , Dultsev Fedor , Latyshev Aleksandr
Published: December 2021

Specific aspects of finely focused electron beam interaction with the PMMA-950K resist for the fabrication of closely spaced holes having inhomogeneous spatial distributions are studied. The technological parameters for the creation of two-dimensional photonic crystals with microcavities (missing holes) arrays, which allow obtaining the lateral sizes of the structure within the accuracy better than 2 %, in silicon using electron-beam lithography are determined. Such holes fabrication accuracy is thought to be sufficient to study the interference effects of cavity array radiation in twodimensional photonic crystals.
Visualization Of Vortex Structures In The Near Field Of The Round Jet Formed In Curved Channel By Piv-Method
Authors: Litvinenko Maria , Litvinenko Yuriy , Vikhorev Valentin
Published: December 2021

The results of experimental investigation of the round jet with Dean vortices (Red = 4 000, De = 1 673) using Particle Image Velocimetry are presented. The measurements were performed with synchronization the phase of acoustic signal and a laser pulse. Instant picture of vorticity field ωz and vector velocity field for the U- and V-components of the jet cross-actions show Dean vortices near the output of the channel in the low velocity gradient field and Kelvin – Helmholtz vortices in the high-velocity gradient field. The presence of Dean vortices distorts two-dimensional vortex ring, which gets an Ω-shaped form, at that the « head» of Ω-vortex outpaces its «legs», as it is in a higher velocity area.
Numerical Modeling Of The Ignition Initiation In The Scramjet Combustion Chamber Via Detonation
Authors: Bedarev Igor , Temerbekov Valentin , Fedorov Aleksandr , Rylova Kristina
Published: December 2021

The paper studies of the cellular detonation wave interaction with supersonic reacting flow in the scramjet combustion chamber. Comparing the flow fields for the details and the reduced chemical kinetics models is allowed verifying the acceptability of the proposed simplified kinetic scheme. The possibility of using pulsating detonation for the ignition intensification in the scramjet combustion chamber is shown. Calculation of the detonation wave interaction with nonpremixed hydrogenair mixture is made. The ability to influence on the hydrogen-air mixing process by means of detonation tube is detected. The effect of tube sizes to intensification of hydrogen air mixing in the flow at channel with a cavity is calculated.
The Circular Gap Couette Flow Modeling
Authors: Lebiga Vadim , Zinoviev Vitaliy , Pak Alexey , Zharov Ivan
Published: December 2021

The simulation of Couette flow inside the circular gap between coaxial cylinders is observed due to the difficulty of the experimental implementation of the equal plane one, especially for rarefied gas conditions and high Knudsen numbers. Geometry configuration of the experimental facility have been defined in order to minimize speed profile deviation inside the gap from linear shape, existing in case of laminar flow and preventing appearance of Taylor – Gërtler vortexes with chosen flow parameters. The previous stage, that was conducted using the hot-wire anemometer in atmosphere pressure conditions has shown the efficiency of the facility and sufficient agreement of calibration data, received using considered calibration method and data of standard calibration approach when the model wind tunnel DISA is applied.
New Type Of Medium – Gases With High Concentration Of Nanoparticles
Authors: Bardakhanov Sergey , Trufanov Dmitriy , Zavialov Alexey
Published: December 2021

The article gives an overview of the works, the results of which indicate the necessity of posing the problem of describing new types of continuous media containing large concentrations of nanoscale particles. The importance of this problem is underlined for understanding modern technological processes in which nanopowders of various nature are formed, and in the form of nanoparticles whose concentration reaches significant values is increasingly used. Examples of practically important flows of powder materials are considered. The concept of a new continuous medium with a high concentration of nanoparticles is proposed, and the «hot-anemometric method» is applied.
Numerical Calculations with a Multi-layer Model of Mixed Sand Transport Against Measurements in Wave Motion and Steady Flow
Authors: Kaczmarek Leszek M.
Published: December 2021

A multi-layer model is used to calculate time-dependent sediment velocity and concentration vertical profiles. This model, in which the differences in sediment transport at different distances from the bed are considered is intended both for the wave motion and steady flow. Numerical calculations were carried out for sediment transport during the wave crest and trough and total sediment transport as a sum of their absolute values. The model concept of variation in shear stress from the skin stress value above the bed to the stress value at the bed previously proposed for steady flow is extended here for the wave motion and verified by direct stress measurements. The calculations were carried out for mixed sand sediments with different grain size distributions including semi-uniform and poorly sorted grains. Comparison with the available small- and large -scale data from flumes and oscillating tunnels yields agreement typically within plus/minus a factor two of measurements.
Statistical Analysis of Electrical and Non-Electrical Parameters of Photovoltaic Modules in Controlled Tracking Systems
Authors: Bugała Artur
Published: December 2021

The paper presents statistical analysis of measurement results of electrical parameters for photovoltaic modules installed in stationary and dual-axis configurations. The parameters which were taken into account included: coefficient of variation, skewness and standard deviation. Also a correlation was determined between independent variables such as insolation, sunshine duration, cloudiness, ambient temperature and atmospheric pressure, and the dependent variable in the form of the daily electricity from photovoltaic conversion. In order to determine the repeatability of electricity waveforms occurring between summer months as well as between summer and winter months, the non-parametric U Mann-Whitney test was used. In order to analyse the repeatability of daily peak hours in which the highest value of the hourly electricity production is observed, the non-parametric Kruskal-Wallis test was used. The tested systems were connected to the power grid and operated independently. Test stands consisting of polycrystalline photovoltaic modules, single-phase on-grid inverters, irradiance sensors and a temperature recorder, were located on the building rooftop of the Faculty of Control Robotics and Electrical Engineering of the Poznan University of Technology in Poland (Central Poland, 52°24.4152′N, 16°55.7958′E) at the height of 30 metres above the ground level. A significant increase in the production of electricity using the PV module spatial positioning system was demonstrated in relation to modules based on the year-round modified design.
Intensive Animal Farming Operations – a Preliminary Analysis of a Number of Farm Animals, Ammonia Emission Values Variability and Methods of Reducing Odor Emissions and Assessing Health Impact Taking into Account Possible Solutions in Poland and Ukraine
Authors: Sówka Izabela
Published: December 2021

The article seeks to review the standards (emission and immission) and legal solutions relating to odour-active compounds, as well asanalyse the variability in the number of farmed animals and the emission of ammonia in Poland and Ukraine. Furthermore, the article characterizesodour emission factors, methods of health risk assessment, ways of limiting emission of odorous compounds from animal farming facilities. The analysis indicated the necessity of applying good practices available in reference documents – including those drawn up by environmental agencies – and scientific works, as such practices may significantly contribute to minimising the impact of animal farming facilities on people and the environment. The introduction of, inter alia, immission standards (reference values) expressed in ouE/m3 in the legal regimes of the EU and Ukraine would also render it possible to carry out an assessment of odours treated as a mixture present in ambient air and optimise the assessment of odour nuisance and thus the discomfort directly affecting the well-being and health of inhabitants of areas in the vicinity of farming facilities.
Kohonen Artificial Networks for the Verification of the Diameters of Water-pipes
Authors: Dawidowicz Jacek
Published: December 2021

The design of the water distribution system is inherently linked to the execution of calculations, which aim, among other things, to determine the flow rate through individual pipes and the selection of diameters at the appropriate speed. Each step in the calculations is followed by an evaluation of the results and, if necessary, a correction of the data and further calculations. It is up to the designer to analyse the accuracy of the calculation results and is time-consuming for large systems. In this article, a diagnostic method for the results of hydraulic calculations, based on Kohonen Network, which classifies nominal diameters [DN] on the basis of data, in the form of flows, has been proposed. After calculating the new variant of the water distribution system, the individual calculation sections are assigned to the neurons of the topological map of Kohonen Network drawn up for nominal diameters. By comparing the diameter used for the calculation, with the diameter obtained on the topological map, the accuracy of the chosen diameter can be assessed. The topological map, created as a result of labelling the neurons of the output layer of the Kohonen Network, graphically shows the position of the classified diameter, relative to those diameters with similar input values. The position of a given diameter, relative to other diameters, may suggest the need to change the diameter of the pipe.
Influence of blenching agents on the mechanical properties and colour of dental restorative nanocomposite
Authors: Adeeb Saja , Adeeb Sanadra , Chladek G.
Published: December 2021

Purpose: Bleaching agents are commonly used to make the natural dentition look more attractive. Currently, in addition to products from reputable manufacturers, products of not fully known origin are available for purchase. The aim of the study was to investigate whether products of this type have a destructive influence on the mechanical and aesthetic properties of the dental restorative nanocomposite.
Design/methodology/approach: Four bleaching agents were used, two recognized brands, and two products were purchased from Chinese websites (their manufacturer is unknown). Two gels and two types of whitening strips were used. One composite nanomaterial was used. Microhardness, diametral tensile strength,, compressive strength and colour measurements were tested.
Findings: For some bleaching agents, studies have shown a relatively small effect on mechanical properties and an acceptable effect on colour changes. Regardless of the observed changes, the use of bleaching agents qualified for the experiment should be considered safe for composites.
Research limitations/implications: The number of blenching agents used as well as dental composites in this study was limited. In future studies, increasing the number of cycles in the bleaching process should be considered.
Practical implications: A popular method of improving the aesthetic properties of teeth is the use of a wide range of blenching agents. Most patients who use teeth whitening procedures are also users of composite fillings. The use of bleaching agents may have a different effect on the mechanical and aesthetic restorative composites. For economic reasons, many people decide to import cheap bleaching agents of unknown or dubious origin via Internet services to perform the bleaching process on their own. In this study, it was investigated whether products of this type have an influence on the mechanical and aesthetic properties of the dental restorative nanocomposite.
Originality/value: Until now, no comparison of the safety of the use of bleaching agents of recognized manufacturers and of unknown origin in terms of the effect on composite materials has been presented, despite their high social importance.
Proton-conducting Organic-inorganic Sulfo-containing Membranes for Fuel Cell
Authors: GRIGORAVICIUTE-PURONIENE Inga , YEVCHUK Iryna , DEMCHYNA Oksana , ZHYHAILO Mariia , RYMSHA Khrystyna , BABKINA Natalia , SHANTALIY Tetyana , RACHIY Bogdan , KAREIVA Aivaras , STANKEVICIUTE Zivile , SKAUDZIUS Ramunas , ZARKOV Aleksej , MUSIY Rostyslav
Published: December 2021

Cross-linked organiс-inorganic sulfo-containing membranes of various compositions based on acrylic monomers (acrylonitrile, acrylic acid, 3-sulfopropylacrylate potassium salt, ethylene glycol diacrylate) and sol-gel systems of tetraethoxysilane have been developed. Synthesis of the polymer matrix was carried out by UV-initiated polymerization of the monomer mixture and the inorganic component was formed in situ while conducting the sol-gel process of the precursor. FTIR, SEM, EDS, DMA, impedance spectroscopy were used to characterize the synthesized materials. The influence of inorganic component content on the properties of the membranes was investigated. DMA results show that an increase in silica content leads to a decrease in packing density and an increase in structural heterogeneity in sulfo-containing polyacrylate/silica membranes. The highest values of proton conductivity 1.12 ꞏ 10−2 Sm/cm at 60 °C were found in membranes containing 3 wt.%. of the added sol-gel system. Further increase of silica content does not increase the proton conductivity of the membranes. The proton transfer activation energies in the membranes were calculated from the temperature dependence of proton conductivity. The obtained cross-linked sulfo-containing organic-inorganic materials can be used for the development of proton-conducting membranes for fuel cells.
Urinary Tract Infection Investigation and Treatment in Older Adults Presenting to the Emergency Department with Confusion: a Health Record Review of Local Practice Patterns
Authors: Pinnell Rhiannan , Ramsay Tim , Wang Han , Joo Pil
Published: December 2021

Background 
The rate of urinary tract infection (UTI) investigation and treatment in confused older emergency department (ED) patients has not been described in the literature. We aim to describe the pattern of practice in an academic tertiary care ED for this common presentation. 
Methods 
A health record review was conducted on 499 adults aged ≥65 presenting to academic EDs with confusion. Exclusion criteria: Glasgow Coma Scale < 13, current treatment for UTI, indwelling catheters, nephrostomy tubes, transfer from another hospital. Outcomes were the prevalence of UTI investigation, diagnosis and antibiotic treatment. 
Results 
64.9% received urine tests, 11.4% were diagnosed with UTI, and 35.2% were prescribed antibiotics. In the subgroup with no urinary symptoms, fever, or other obvious indication for antibiotics, these numbers were 58.2%, 7.6%, and 18.1%, respectively. Patients who had urine tests or received antibiotics were older than those who did not (p values < .01). Patients receiving antibiotics had higher admission rates and 30-day and six-month mortality (OR of 2.9 [2.0–4.3], 4.0 [1.6–11], and 2.8 [1.4–5.8], respectively). 
Conclusion 
Older patients presenting to ED with confusion were frequently investigated and treated for UTI, even in the absence of urinary symptoms. Antibiotic treatment was associated with higher hospitalization and mortality.
Die Sinus-Milieus in der Gesellschaftswissenschaft
Authors: Barth Bertram
Published: December 2021

Der Aufsatz nimmt Bezug auf die Diskussion des Drei-Klassen-Modells von Reckwitz und dessen empirischer Fundierung durch die Sinus-Milieus. Nach einer Darstellung der Entwicklung und Konstruktion der Sinus-Milieus werden die Spezifika privat finanzierter Forschung skizziert. Abschließend wird die Differenzierungskraft des Modells an den Beispielen der „alten Mittelklasse“ von Reckwitz sowie der AfD-Wählerschaft bei den Landtagswahlen 2019 in Sachsen, Thüringen und Brandenburg erläutert.
Investigation on the Stress of Chinese Pediatricians Under the Outbreak of COVID-19
Authors: Yang Lan , Zhang Bingbing , Kong Xiaoxing , Zhou Weifang , Tian Jianmei , Cai Shizhong , Cheng Fangfang
Published: December 2021

Background: The Coronavirus disease 2019 (COVID-19) pandemic has posed a severe threat to international health and the economy. Clinicians, the main staff involved in fighting against the pandemic, are under great pressure. However, relevant mental stress studies are lacking at present. Objectives: This study aimed to explore the mental stress level and its influencing factors among Chinese pediatricians under the outbreak of COVID-19, aiming to provide a certain theoretical basis for relevant psychological intervention among medical staff. Methods: In this cross-sectional study, 352 in-service pediatricians were selected from nine hospitals in Jiangsu province, China, in February 2020. The online survey was performed to collect general information. Meanwhile, the Perceived Stress Scale (PSS-10), Self-rating Anxiety Scale (SAS), and Pittsburgh Sleep Quality Index (PSQI) scale were employed for assessment. Afterward, the stress level and influencing factors among pediatricians were analyzed through descriptive analysis, one-way analysis of variance (ANOVA), correlation analysis, and multiple linear regression analysis. Results: The mean score of PSS-10 showed moderate stress on the whole. Pediatricians from outpatient and emergency departments had significantly higher perceived stress than those from other departments. The perceived stress was significantly associated with age, educational level, professional title, work experience, and physical condition. Stepwise multiple linear regression showed that age, professional title, and physical condition had a linear relationship with the individual’s perceived stress. Besides, Pearson correlation analysis indicated that perceived stress was associated with anxiety level and sleep quality. Conclusions: Under the outbreak of COVID-19, pediatricians suffer from relatively high levels of mental stress. The influencing factors include education, age, professional title, work experience, and physical condition. Typically, the anxiety level and sleep quality are correlated with the mental stress among pediatricians.
Performance of Undergraduate Medical Students in Formative and Summative Evaluations in Community Medicine in a Medical College in India
Authors: Bhattacharya Saikat , Mondal Soumitra , Mitra Kaushik
Published: December 2021

Background: Assessment and evaluation should be a continuous activity associated with curriculum development. Continuous formative examinations are the stepping stone for good learning and better performance in summative examination. However, the correlation or predictability of formative examinations has not been quantified in the community medicine subject in the bachelor of surgery (MBBS) course in India. Objectives: The objective of this study was to explore the correlation of performance in continuous assessments and final summative evaluation in third-year professional MBBS students in community medicine and the predictability of formative scores for the final examination marks. Methods: An institution-based retrospective longitudinal study was conducted in the Medical College of Kolkata, India. A total of 237 undergraduate medical students were followed up for two years to track their results in three successive examinations. The scores obtained in formative and summative evaluations in third-year professional MBBS students in community medicine were analyzed to find out the correlation between them, and multiple linear regression was also performed in SPSS. Results: The strong and significant correlation (0.64) between the sixth semester and internal examination results suggests the importance of the sixth semester examination for the preparation of finals. The third semester examination, although conducted two years prior to the finals, still had significant correlation with the finals, but the correlation was weak (0.17). Conclusions: Formative examination in community medicine, which spans for overall three and half years, plays an essential role in the preparation of students for the finals, more so for achieving good scores. Performance in these two examinations can only explain more than one fourth of the variability of the performance in the finals.
Fear of Missing Out and Problematic Social Media Use: A Research Among University Students in Turkey
Authors: ÇETİNKAYA Ahmet , KIRIK Ali Murat , GÜNDÜZ Uğur
Published: December 2021

This study examines the relationship of fear of missing out (FOMO) with heavy social networking among Turkish university students (aged 17 - 55). Factor analysis of FOMO scale led us to evaluate the construct under two dimensions as (1) fear of missing experience and (2) fear of missing activity. The results revealed that fear of missing activity increases social media intrusion while fear of missing experience is found to have no significant effect. The reverse relationship is also valid: an urge to use social media predicts fear of missing out (activity and experience). Fear of missing experience is associated with problematic social media use (PSMU) and a high desire to use social media.
O DIREITO À DIVERSIDADE SEXUAL E DE GÊNERO A PARTIR DO DIÁLOGO ENTRE O SISTEMA GLOBAL E O INTERAMERICANO DE PROTEÇÃO DOS DIREITOS HUMANOS
Authors: Carvalho Grasielle Borges Vieira de , Duarte Júnior Dimas Pereira , Souza Daniela De Andrade
Published: December 2021

O presente artigo tem por objetivo analisar o direito à diversidade sexual e de gênero a partir de um estudo comparativo dos sistemas de proteção dos direitos humanos a nível global e interamericano. Pretende-se responder à problemática que diz respeito à possibilidade de um diálogo complementar entre os sistemas para maior eficácia na proteção de direitos humanos a nível internacional. Para tanto, é empregado o método qualitativo, com o uso de revisão bibliográfica bem como de pesquisa documental sobre relatórios de conferências e resoluções acerca da temática, utilizando o caminho desde o início da entrada na agenda dos sistemas internacionais. Deste modo, ao utilizar a expressão de gênero e sexualidade, considera-se que o sistema global, que confere tratamento universalizante aos direitos humanos, e o sistema interamericano, que se restringe geograficamente a uma localidade com suas peculiaridades, podem interagir de forma a atuar simultaneamente e de forma complementar numa proteção multinível dos indivíduos.
PANDEMIA Y TRABAJADOR AUTÓNOMO: SOLUCIONES ARTICULADAS EN EL CONTEXTO EUROPEO PARA CONJURAR ESTA POSIBLE NUEVA FORMA DE POBREZA LABORIOSA
Authors: Salas Porras María
Published: December 2021

O estudo que se apresenta a seguir tenta cumprir um duplo objetivo. Por um lado, apresentam a possível extensão que teria sofrido o conceito de pobreza laboriosa face à crise de saúde no que diz respeito à oferta de políticas sociais dirigidas aos trabalhadores por conta própria - grupo que, em situações normais, não atinge os padrões de proteção esperados pela OIT em sua agenda de Trabalho Decente. E, por outro lado, a apresentação das medidas adotadas pelos países membros da União Européia que, sem uma orientação clara do nível supraestadual, acabam convergindo. Estes lugares-comuns mostram que, com efeito, o trabalhador independente se revela, depois da crise de saúde provocada pela COVID, como um grupo à beira da exclusão social por falta de previsão por parte dos Estados-Membros, de medidas estruturais. de proteção social.
La fotografía como expresión del concepto
Authors: Machado Arlindo
Published: December 2021

De tanto en tanto, la discusión sobre la naturaleza más profunda de la fotografía vuelve a la superficie con insistencia. En esas ocasiones, todo lo que parecía sólido se disuelve en el aire. Dentro de algunas décadas, la fotografía cumplirá los dos siglos de existencia y, todavía entonces, estaremos tratando de entenderla. Estas dificultades tienen buenos fundamentos. La fotografía es la base tecnológica, conceptual e ideológica de todos los medios contemporáneos y, por ese motivo, comprenderla, definirla, es un poco también comprender y definir las estrategias semióticas, los modelos de construcción y percepción, las estructuras en las que se sustenta toda la producción contemporánea de signos visuales y auditivos, sobre todo de aquélla que se hace a través de mediación técnica. Cada vez que se introduce un medio nuevo, éste sacude las creencias establecidas anteriormente y nos obliga a volver a los orígenes para revisar las bases a partir de las cuales edificamos la sociedad de los medios. La televisión y, por extensión, la imagen y sonido electrónicos, ya nos hicieron encarar esa indagación hace algunas décadas. Ahora, el procesamiento digital y la modelación directa de la imagen en la computadora nos enfrentan a nuevos problemas y nos hacen mirar retrospectivamente, en el sentido de revisar las explicaciones que hasta entonces sustentaban nuestras prácticas y teorías. En un momento como éste, en que la imagen y también el sonido pasan a ser sintetizados a partir de ecuaciones matemáticas y de modelos de la física, en un momento en que hasta el mismo registro fotográfico puede ser memorizado en forma numérica, es necesario revisar buena parte de nuestros paradigmas teóricos.
Reseña de: Jaume Lloret i Esquerdo: El teatre a Alacant 1833-1936. Valencia. Consell Valencia de Cultura, 1998. Prólogo de Josep Lluís Sirera. Fotografías de Vicent Segura
Authors: Sansano Gabriel
Published: December 2021

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DUT Guide om løbende bedømmelse
Authors: Bjælde Ole Eggers , Lindberg Annika Büchert
Published: December 2021

Løbende bedømmelse er en relativt ny eksamensform i Danmark, som giver mulighed for at supplere en afsluttende eksamen med bedømmelsesaktiviteter i løbet af undervisningsperioden, som tæller med i den studerendes samlede karakter. Løbende bedømmelse kan derfor blive en måde, hvorpå eksamen knyttes bedre til undervisningen og giver de studerende mere retvisende eksamenskarakterer. Med fokus på bedre uddannelse og undervisning på de videregående uddannelser vil det formentlig blive en mere udbredt eksamensform med tiden. I guiden her præsenteres praksisnære råd til undervisere og undervisningsudviklere om løbende bedømmelse baseret på forskning, danske og internationale erfaringer samt den hidtidige implementering af eksamensformen på danske videregående uddannelser.
A note on smooth forms on analytic spaces
Authors: Andersson Mats , Samuelsson Kalm Håkan
Published: December 2021

We prove that any smooth mapping between reduced analytic spaces induces a natural pullback operation on smooth differential forms.
A Schwarz lemma for hyperbolic harmonic mappings in the unit ball
Authors: Chen Jiaolong , Kalaj David
Published: December 2021

Assume that $p\in [1,\infty ]$ and $u=P_{h}[\phi ]$, where $\phi \in L^{p}(\mathbb{S}^{n-1},\mathbb{R}^n)$ and $u(0) = 0$. Then we obtain the sharp inequality $\lvert u(x) \rvert \le G_p(\lvert x \rvert )\lVert \phi \rVert_{L^{p}}$ for some smooth function $G_p$ vanishing at $0$. Moreover, we obtain an explicit form of the sharp constant $C_p$ in the inequality $\lVert Du(0)\rVert \le C_p\lVert \phi \rVert \le C_p\lVert \phi \rVert_{L^{p}}$. These two results generalize and extend some known results from the harmonic mapping theory (D. Kalaj, Complex Anal. Oper. Theory 12 (2018), 545–554, Theorem 2.1) and the hyperbolic harmonic theory (B. Burgeth, Manuscripta Math. 77 (1992), 283–291, Theorem 1).
On homotopy nilpotency of the octonian plane $\mathbb{O}P^2$
Authors: Golasi´nski Marek
Published: December 2021

Let $\mathbb{O}P^2_{(p)}$ be the $p$-localization of the Cayley projective plane $\mathbb{O}P^2$ for a prime $p$ or $p=0$. We show that the homotopy nilpotency class $\textrm{nil} \Omega(\mathbb{O}P^2_{(p)})<\infty $ for $p>2$ and $\textrm{nil} \Omega (\mathbb{O}P^2_{(p)})=1$ for $p>5$ or $p=0$. The homotopy nilpotency of remaining Rosenfeld projective planes are discussed as well.
Generalized John Gromov hyperbolic domains and extensions of maps
Authors: Zhou Qingshan , Li Liulan , Rasila Antti
Published: December 2021

Let $\Omega \subset \mathbb{R}^n$ be a Gromov hyperbolic, $\varphi$-length John domain. We show that there is a uniformly continuous identification between the inner boundary of $\Omega$ and the Gromov boundary endowed with a visual metric, By using this result, we prove the boundary continuity not only for quasiconformal homeomorphisms, but also for more generally rough quasi-isometries between the domains equipped with the quasihyperbolic metrics.
Advancing the Provision of Mental Health Services and Supports on College and University Campuses: Toolkit and Resource Guide
Authors:   Social Solutions International, Inc.
Published: December 2021

The purpose of this Toolkit and Resource Guide is to provide a framework for US-based colleges and universities to advance their approach to mental health services and supports to their students. At a time when student demand for mental health services and supports has never been greater, so, too, has the challenge never been greater for universities to find ways to keep pace with this demand. In practice for colleges and universities, this means re-thinking their approach to mental health service and support provision, identifying areas of improvement with respect to how current systems are structured, examining novel ways of providing mental health services and supports, and finding new opportunities for collaboration beyond traditional individual counseling. This Toolkit and Resource Guide aims to support colleges and universities in this important journey. The Toolkit contains the following modules, which each examine a different aspect of this journey. Disclaimer: The content of this publication does not necessarily reflect the views, opinions or policies of the Center for Mental Health Services (CMHS), the Substance Abuse and Mental Health Services Administration (SAMHSA) or the Department of Health and Human Services (HHS), and the inclusion of information about campus programs and select resources does not constitute official endorsement of the programs and resources. This publication was produced for the Substance Abuse and Mental Health Administration (SAMHSA). It was prepared by Social Solutions International, Inc. under contract HHSP233201700193A.