bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of gas permeability of abrasive tools on their structural and mechanical parameters
Authors: Bagaiskov Yu 
Published: December 2021

Abstract
Quality assurance and processing capacity are essential performance parameters of abrasive tools. It is of prime importance for grinding wheels operating at a speed of 35–60 m/s. In this case, the opportunities to increase the high-rate grinding efficiency without burns are associated with using high-porosity and low-hardness wheels. Artificial pore-forming agents are used to manufacture tools. Introduction of pore-forming agents decreases grinding forces and increases the maximum grinding depth without burns. The porosity of filled compound materials can be attributed to the conception of gas permeability. The gas permeability parameter describes the openness degree of such structures and the velocity of the air volumes passing through porous materials. The porosity and gas-permeability degrees of the material of high-porous ceramic-bond abrasive tools with various parameters, depending on the abrasive material type, porogen grain size and content, and the composite structure number have been studied. It appeared that the porosity degree of high-porous abrasive tools, made both of fused alumina and silicon carbide increases as the structure number, grain size, and content of burning porogens increases. Besides, the increase degree of fused alumina is a little higher than that of silicon carbide. The gas permeability degree depends on the factors mentioned above in nearly the same way. Compared to porosity, the effect of gas permeability increases due to an altered structure, grain size, and content of porogens is much higher, up to 6 times. In this case, the gas permeability value is primarily characteristic of the pore size; in other words, the speed and volume of the air or lubrication and cooling fluid penetrating the material structure increase correspondingly at nearly the same increase of the pore size by several times and at the same volume porosity degree. The gas permeability degree can be used for quantitative and qualitative description of the material structure of high-porous abrasive tools, as well as their structural and mechanical parameters. The operating parameters of tools can depend on the gas permeability level of their materials. Thus, the results of abrasive processing can be foreseen.
Assessment of the current technical condition of electrical equipment based on an artificial neural network
Authors: Manusov V Z , Otuzbaev M R , Scherbinina M A , Ivanov G V 
Published: December 2021

Abstract
Assessment of the current technical condition is an important task, so the state of electrical equipment depends on its further operability. Thanks to modern computing devices, it is possible to implement actively artificial intelligence and computer-assisted learning methods that allow achieving high efficiency in data processing. A study was conducted and an algorithm for diagnosing the technical condition based on an artificial neural network was developed. A model based on a multilayer perceptron is proposed, which allows evaluating the technical condition of a high-voltage power transformer. The result of the technical diagnostics of the model is the assignment of the condition to one of the five classes, proposed by the guidelines presented by the International Council on Large Electrical Systems. The methodology is presented on the example of a 250 MVA transformer with a certain defect history, which allowed us to show the reliability and validity of the obtained results. It is shown that the use of the proposed model makes it possible to achieve accuracy in determining the technical condition of 0.95. The introduction of this model into an automated monitoring and diagnostics system will allow assessing the technical condition of electrical equipment in real time with sufficient accuracy.
Short-term forecasting of wind and solar power generation
Authors: Manusov V Z , Khaldarov S K , Palagushkin B V 
Published: December 2021

Abstract
It is important to note that the generated power of renewable sources depends on the natural conditions at a particular geographic point, the level of wind flow speeds and solar radiation. The patterns characterizing these parameters depend on the time of year, locality and are purely probabilistic in nature. Taking into account the above-mentioned conditions for the effective implementation of “green” objects in the power supply system, the purpose of this work is to build forecasting models that are more likely to be able to determine what part of the load can be covered by the power supply system based on wind power and solar installations. This purpose was achieved by constructing and training artificial neural networks with data on the speed of wind flow and solar radiation obtained from real renewable energy facilities. The most significant result is the identification of the necessary forecasting horizon, taking into account the preservation of a relatively good quality of metrics, as well as understanding what additional data is required to improve this quality. The significance of the results obtained lies in the fact that they make it possible to determine what reserve capacity is required to be included in the project.
The comparison of a discrete-continuous approach and a method of finite differences in solving the problem of unsteady-state heat and moisture transfer in the building envelope
Authors: Zhou Z , Zubarev K P 
Published: December 2021

Abstract
This article is devoted to the development of methods for calculating heat and humidity regime in the building envelope. The equation of steady-state thermal conductivity with boundary conditions of the third kind and the formula for calculating heat losses of a building based on the heat transfer equation have been considered. The equation of unsteady-state thermal conductivity as well as its solution using the discrete-continual approach has also been studied. The solution of the unsteady-state heat conductivity problem with invariable over time boundary conditions using the discrete-continuous approach was proposed by A.B. Zolotov and P.A. Akimov. The subsequent modernization of the solution was conducted by V.N. Sidorov and S.M. Matskevich. The unsteady-state equation of moisture transfer based on Fick’s second law using the theory of moisture potential is derived. The solution of the unsteady-state moisture transfer equation using the finite difference method according to an explicit difference scheme as well as the solution of the unsteady-state moisture transfer equation using the discrete-continuous approach is demonstrated. To prove the effectiveness of using the discrete-continuous approach in the area of the unsteady-state humidity conditions we compared the calculation results of the distribution of moisture in a single-layer enclosing structure made of aerated concrete using two methods of moisture potential theory. It was found that the difference in the results of calculation by the discrete-continual formula and by the method of finite differences does not exceed 3.2%.
Temperature regime of painted parts in awning-type drying chambers at low ambient temperatures
Authors: Yakovlev P , Prosvirina I 
Published: December 2021

Abstract
The paper considers the problem of colouring large-sized objects, such as modules of sea and river vessels at low ambient temperatures. The temperature distribution depends on the thermal resistance of the walls of the drying chamber, the main characteristics of the heater fan, the dimensions of the chamber and the painted module, the gaps between the walls. The calculation should take into account the aerodynamic resistance of the drying chamber with the part placed in it, the influence of free convection, heat loss and the peculiarities of air distribution inside the shelter. The paper presents the results of a study of the influence of the size of the drying chamber, the size of the painted module, ambient temperatures and air coming from the heater, fan parameters, methods of placing the fan and exhaust ventilation on the range of air temperature changes in the tent. The methods of numerical modelling and experimental studies were used in the study. Based on the results obtained, a calculation method is proposed that allows determining the decrease in temperature inside the chamber relative to the temperature of the air coming from the heater. To automate the calculations, a program has been developed to determine the parameters of the air after heating with a fan heater.
Heat capacity of dispersed rocks
Authors: Galkin A F , Yu Pankov V 
Published: December 2021

Abstract
Protection of automobile roads from negative cryogenic processes is a current issue to which significant attention is devoted in both scientific and engineering communities. In many cases important for practice, the the thermal factor determines the reliability and security of the use of the road in the cryolithic zone. The heat capacity of dispersed rocks is among the most important indicators of the physical properties determining the intensity of thermal processes in the road surfaces and road foundations. The precision of determination of the total heat capacity of the rocks in thawed and frozen state largely determines the precision of the forecast of the thermal regime of roads in the cryolithic zone. A complex assessment of the impact of ice content of the dispersed rocks on the value of total heat capacity was done. 2D and 3D charts which allow to assess the possible range of change in the heat capacity of the dispersed rocks in thawed and frozen state, in both a wide range and in the typical range of values, were produced. Among the main criteria determining the extent of the seasonal freezing and thawing of the soils of the active layer is the Stefan number, a dimensionless criterion. An overall assessment of the impact of ice content on the ground (rock) foundations of the roads and of the air temperature in the warm period of the year on the quantitative values of the Stefan number was done. Charts allowing to determine in both a wide and typical range the changes of values of the Stefan numbers, permitting to assess the possible range of changes of the Stefan number, were made. It was determined, in particular, that for the typical dispersed rocks of the road foundations in the cryolithic zone the range of change in the Stefan numbers is 2.1-6.5.
Determination of melt composition in an open-arc ore-thermal furnace
Authors: Vasilev V V 
Published: December 2021

Abstract
The aim of the study is to improve the technical and economic performance of the normal electrocorundum production process in an ore-thermal furnace by automated control of the melt composition at the final stage. The essence of the research is to exploit the valve effect of an AC arc. The expression for the Al2O3 content in the melt was obtained from the electrical characteristics of the melt. Studies have shown a fairly high degree of accuracy in the convergence of the results of the proposed method with laboratory data.
Investigation of the effect of laser surface modification on the hardness and wear resistance of a titanium alloy
Authors: Belyaev L V , Zhdanov A V 
Published: December 2021

Abstract
The effect of laser modification of the surface on the value of the coefficient of elasticity, hardness, coefficient of friction and the amount of wear of the counter body when testing products made of a deformable titanium alloy was investigated. It was found that the indicators of hardness and wear resistance of a titanium alloy depend on the modes of laser modification. These dependencies are extreme in nature, they have maxima and minima. The quantitative values of hardness and wear resistance indicators for the specified material before and after laser treatment of its surface in various modes are given.
Local thermodynamic equilibrium in a laser-induced plasma channel formed by interaction of femtosecond laser radiation with argon
Authors: Kochuev D A , Galkin A F , Chernikov A S , Chkalov R V , Voznesenskaya A A , Khorkov K S , Egorova A V 
Published: December 2021

Abstract
In this paper, we estimate the possibility of applying local thermodynamic equilibrium conditions for a laser-induced plasma channel formed by femtosecond laser radiation in an argon medium at different pressures. The presence of a local thermodynamic equilibrium was determined on the basis of the time of heat exchange of electrons with argon atoms. The Saha equation is used to estimate the concentration of free electrons, the temperature of the laser-induced plasma channel, and its conductivity. A necessary condition for using this ratio was the presence of a state of local thermodynamic equilibrium in the plasma under study.
Surface acoustic wave temperature properties in alpha-GeO2 crystal
Authors: Taziev R M 
Published: December 2021

Abstract
In this study, the surface acoustic wave (SAW) temperature properties in flux-grown α-GeO2 crystal are numerically investigated. It is shown that the SAW velocity temperature change substantially depends only on the temperature coefficient of three elastic constants: C66, C44 and C14 for crystal cuts and wave propagation directions, where SAW has high electromechanical coupling coefficient. The SAW temperature coefficient of delay (TCD) for these crystal cuts are in the range from -40 ppm /°C to -70 ppm /°C. In contrast to alpha-quartz, the surface wave TCD values are not equal to zero in Z-, Y- , and Z- rotated cuts of α-GeO2 single crystal. Its values are comparable in the magnitude with the surface wave TCD values in lithium tantalate. In the crystal grown from the melt, the interdigital transducer (IDT) conductance has two times larger amplitude than that in hydrothermally grown a-GeO2. The leaky acoustic wave excited by IDT on Z+120°-cut and wave propagation direction along the X-axis, has an electromechanical coupling coefficient 5 times less than that for surface wave.
A phenomenological theory-based viscosity model for shear thickening fluids
Authors: Lin Kun , Qi Jiapeng , Liu Hongjun , Wei Minghai , Peng Hua Yi 
Published: December 2021

Abstract
A viscosity model for shear thickening fluids (STFs) based on phenomenological theory is proposed. The model considers three characteristic regions of the typical material properties of STFs: a shear thinning region at low shear rates, followed by a sharp increase in viscosity above the critical shear rate, and subsequently a significant failure region at high shear rates. The typical S-shaped characteristic of the STF viscosity curve is represented using the logistic function, and suitable constraints are applied to satisfy the continuity of the viscosity model. Then, the Levenberg–Marquardt algorithm is introduced to fit the constitutive model parameters based on experimental data. Verification against experimental data shows that the model can predict the viscosity behavior of STF systems composed of different materials with different mass concentrations and temperatures. The proposed viscosity model provides a calculation basis for the engineering applications of STFs (e.g., in increasing impact resistance and reducing vibration).
Substrate specificity of glycoside hydrolase family 1 β-glucosidase AtBGlu42 fromArabidopsis thalianaand its molecular mechanism
Authors: Horikoshi Shu , Saburi Wataru , Yu Jian , Matsuura Hideyuki , Cairns James R Ketudat , Yao Min , Mori Haruhide 
Published: December 2021

ABSTRACTPlants possess many glycoside hydrolase family 1 (GH1) β-glucosidases, which physiologically function in cell wall metabolism and activation of bioactive substances, but most remain uncharacterized. One GH1 isoenzyme AtBGlu42 in Arabidopsis thaliana has been identified to hydrolyze scopolin using the gene deficient plants, but no enzymatic properties were obtained. Its sequence similarity to another functionally characterized enzyme Os1BGlu4 in rice suggests that AtBGlu42 also acts on oligosaccharides. Here, we show that the recombinant AtBGlu42 possesses high kcat/Km not only on scopolin, but also on various β-glucosides, cellooligosaccharides, and laminarioligosaccharides. Of the cellooligosaccharides, cellotriose was the most preferred. The crystal structure, determined at 1.7 Å resolution, suggests that Arg342 gives unfavorable binding to cellooligosaccharides at subsite +3. The mutants R342Y and R342A showed the highest preference on cellotetraose or cellopentaose with increased affinities at subsite +3, indicating that the residues at this position have an important role for chain length specificity.
GC Determination of Fluorouracil in Serum by Using Hexafluroroacetylacetone as Derivatizing Reagent
Authors: Zounr Rizwan Ali , Khuhawar Muhammad Yar , Khuhawar Taj Muhammad Jahangir , Lanjwani Muhammad Farooque , Khuhawar Muzamil Yar 
Published: December 2021

Abstract
A gas chromatographic (GC) procedure has been developed for the determination of fluorouracil (5-FU) after pre-column derivatization with hexafluoroacetylacetone. GC separation was from column DB-1 (30 m × 0.32 mm id) and the determination was by flame-ionization detection. The derivatization conditions were optimized at pH 4, heating at 90°C for 40 min and extraction of the derivative was in chloroform. Using the conditions nucleobases cytosine, uracil, thymine, adenine and guanine separated completely from fluorouracil. The linear calibration range and LOD for 5-fluorouracil were 0.5–40.0 and 0.2 μg/mL, respectively. The derivatization, elution and separation were repeatable in terms of retention time and peak height/peak area (n = 5) and relative standard deviations (RSD) were within 3.5%. The method was applied for the analysis of serum spiked with 5-FU with recovery of 95.5–97.5% with RSD 1.5–3.1%.
Effectiveness of 13-Valent Pneumococcal Conjugate Vaccine Against Medically Attended Lower Respiratory Tract Infection and Pneumonia Among Older Adults
Authors: Lewnard Joseph A , Bruxvoort Katia J , Fischer Heidi , Hong Vennis X , Grant Lindsay R , Jódar Luis , Cané Alejandro , Gessner Bradford D , Tartof Sara Y 
Published: December 2021

Abstract

Background
Among older adults, 13-valent pneumococcal conjugate vaccine (PCV13) has been found efficacious against nonbacteremic pneumonia associated with vaccine-serotype pneumococci. However, the burden of lower respiratory tract infection (LRTI) and pneumonia preventable by direct immunization of older adults continues to be debated.

Methods
We analyzed data from an open cohort of adults aged ≥65 years enrolled in Kaiser Permanente Southern California health plans from 2016 to 2019 who received PCV13 concordant with US Advisory Committee on Immunization Practices guidelines. We estimated PCV13 vaccine effectiveness (VE) via the adjusted hazard ratio for first LRTI and pneumonia episodes during each respiratory season, comparing PCV13-exposed and PCV13-unexposed time at risk for each participant using a self-matched inference framework. Analyses used Cox proportional hazards models, stratified by individual.

Results
Among 42 700 adults who met inclusion criteria, VE was 9.5% (95% confidence interval [CI], 2.2% to 16.3%) against all-cause medically attended LRTI and 8.8% (95% CI, –.2% to 17.0%) against all-cause medically attended pneumonia. In contrast, we did not identify evidence of protection against LRTI and pneumonia following receipt of the 23-valent pneumococcal polysaccharide vaccine. PCV13 prevented 0.7 (95% CI, .2 to 1.4) and 0.5 (95% CI, .0 to 1.0) cases of LRTI and pneumonia, respectively, per 100 vaccinated persons annually; over 5 years, 1 case of LRTI and 1 case of pneumonia were prevented for every 27 and 42 individuals vaccinated, respectively.

Conclusions
PCV13 vaccination among older adults substantially reduced incidence of medically attended respiratory illness. Direct immunization of older adults is an effective strategy to combat residual disease burden associated with PCV13-type pneumococci.
Detecting cardiomyopathies in pregnancy and the postpartum period using ECG
Authors: Adedinsewo D , Johnson P W , Douglass E J , Attia Z I , Phillips S D , Goswami R M , Yamani M H , Connolly H M , Rose C H , Sharpe E E , Lopez-Jimenez F , Friedman P A , Carter R E , Noseworthy P A 
Published: December 2021

Abstract

Background
Cardiovascular disease (CVD) has been identified as a major threat to maternal health in the US and UK with cardiomyopathy being one of the most common acquired CVD in the pregnant and postpartum period. Diagnosing cardiomyopathy in pregnancy is challenging due to an overlap of cardiovascular symptoms with normal pregnancy symptoms.

Purpose
The purpose of this study was to evaluate the effectiveness of an ECG based deep learning model in identifying cardiomyopathy among pregnant and postpartum women.

Methods
We utilized an ECG based deep learning model to detect cardiomyopathy in a cohort of pregnant or postpartum women seen at multiple hospital sites. Model performance was evaluated using area under the curve (AUC), accuracy, sensitivity, and specificity. We compared the diagnostic probabilities of the deep learning model with natriuretic peptides and a multivariable model consisting of demographic and clinical parameters.

Results
1,807 women were included. 7%, 10% and 13% had LVEF ≤35%, &lt;45% and &lt;50% respectively. The ECG based deep learning model identified cardiomyopathy with an AUC of 0.92 for left ventricular ejection fraction (LVEF) ≤35%, 0.89 for LVEF &lt;45% and 0.87 for LVEF &lt;50%. For LVEF ≤35%, AUC was higher in Black (0.95) and Hispanic (0.98) women compared to white (0.91). Natriuretic peptides and the multivariable model had AUCs of 0.85 and 0.72 respectively.

Conclusions
A deep learning model effectively identifies cardiomyopathy in pregnant or postpartum women, outperforms natriuretic peptides and traditional clinical parameters with the potential to become a powerful initial screening tool for cardiomyopathy in the obstetric care setting.

Funding Acknowledgement
Type of funding sources: Other. Main funding source(s): This study was made possible using resources supported by the Mayo Clinic Women's Health Research Center and the Mayo Clinic Building Interdisciplinary Research Careers in Women's Health (BIRCWH) Program funded by the National Institutes of Health (NIH), grant number K12 HD065987. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.