bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental research with the help of thermal derivatographic analysis on coal powder that can be blowed in the furnace
Authors: Caloian V , Vlad E M , Oancea V , Hritac M , Plopeanu E F , Pandelescu C , Rucai V , Constantin N
Published: February 2021

In an integrated steel flow, the costs related to the consumption of metallurgical coke represent approx. 25% of the production cost of the shards obtained by continuous casting. As the price of coal returns to about 50% of that of coke, the technology of insufflating coal dust at the blast furnaces mouths, which transfers the coking process to the blast furnace, can reduce the cost of slag by 4-5%. It cannot be used to blow into the furnace any type of coal. The coal used must meet certain requirements, based on its physical and chemical properties. By thermo-derivatographic analysis, important properties of coals can be established. The authors present in this paper the results of thermal derivatographic analyzes performed on certain types of coal.
Experimental research on the effect of additives on the sintering process of alumina-based refractory materials
Authors: Vlad E M , Buzduga R V , Buzduga M D , Caloian V , Plopeanu E F , Pandelescu C , Dobrescu C , Constantin N
Published: February 2021

This experimental study refers to the obtaining of refractory materials based on alumina, by adding different amounts of TiO2 and MnO2, as sintering agents, to the initial mixtures of raw materials (alumina, chamotte), followed by the sintering of the mass’s different temperatures between 1300 ºC and 1700 ºC. The effects of the use of additives on the sintering temperature, as well as on the microstructure and, consequently, on the properties of the sintered materials were analysed on both the added and non-added ceramic samples, considered as comparative benchmarks.
Building a blockchain for aviation maintenance records
Authors: Andrei A G , Balasa R , Costea M L , Semenescu A
Published: February 2021

The objective of this paper was to create a proof of concept for a blockchain application in aviation world, with an emphasis on improving the aircraft maintenance traceability. It is well known that aviation industry manages incredible complex systems, where failure is not an option. This industry needs blockchain technology not only for safety improvements but also for a new business model where airline companies can deliver more trust and more transparency to their customers.

Nowadays, the passengers who are the end customers, cannot evaluate an airline company from the point of view of fleet maintenance. Bad or uncomplete maintenance are premises for an undesired accident. Moreover, aircraft investigators and auditors are experiencing difficulties in understanding how an aircraft was operated. Thinking of forecasting defects, models of predictive maintenance cannot be developed if accurate data are not available. All these can be changed with the implementation of the proposed blockchain application.

Beside the theoretical explanations, the scope of this work was also to put in practice the main blockchain features and develop on a small scale, a real decentralized blockchain application using Python programming language. The script was designed to run on a localhost machine and store maintenance records and relevant parameters for the process of tracking an airplane’s lifespan in a chain of interconnected blocks.

Therefore, the traditional approach in the data management is no longer an option for the aviation industry.
Methane combustion kinetic schemes in FlowVision software
Authors: Krikunova A I
Published: February 2021

The two-step chain reaction of methane combustion in air is integrated into the FlowVision software package. The conical flame numerical simulation under normal conditions using the built-in single-step chemical reaction was performed. A comparative analysis of the numerical results for one- and two-step schemes, as well as experimental results was made.
Estimation of the flux density of galactic comets in the Orion–Cygnus branch based on number of shield volcanoes on Venus, craters on Mars and marine basins on the Moon
Authors: Barenbaum A A , Shpekin M I
Published: February 2021

Based on data on shield volcanoes of Venus and the distribution of craters on Mars and sea basins on the Moon, the flux density of galactic comets in the Orion–Cygnus branch was calculated. The comets flux density is 5 × 10−10 year−1 km−2. This value was used to estimate the number, energy and fallings frequency of galactic comets on terrestrial planets in the period from ≈ 5 to 1 million years ago. The article shows, that the falls of such comets can explain the phenomena of “newest uplifts of Earth’s crust” and “young volcanism” on Earth, the appearance of shield volcanoes on Venus, the asymmetric structure of Mars, as well as origin of large craters, seas and mascons on the Moon, Mars and Mercury. A hypothesis of formation on the Moon of the South Pole–Aitken basin by galactic comets is proposed.
Thermalization of the plasma arising during counter collision of high-energy plasma flows in a longitudinal magnetic field
Authors: Gavrilov V V , Eskov A G , Zhitlukhin A M , Kochnev D M , Pikuz S A , Poznyak I M , Ryazantsev S N , Skobelev I Yu , Toporkov D A , Umrikhin N M
Published: February 2021

This work is devoted to the study of thermalization of plasma created by head-on collisions of high-energy plasma flows in a longitudinal magnetic field of 0.5–2 T. Hydrodynamic flows contained the energy of 200 kJ with velocities from 2 × 107 to 4 × 107 cm/s and ion density from 2 × 1015 to 4 × 1015 cm−3 were created inside the 2MK-200 facility by two electrodynamic plasma accelerators equipped by a system of pulsed gas injection. Nitrogen, neon and their mixtures with hydrogen and deuterium were implemented as working gases. A process of plasma creating was investigated by near-wall magnetic probes situated in different parts of the interaction chamber. Temporal evolution of the plasma electron temperature had been traced by x-ray photodiodes covered by different filters. It was discovered that the plasma electron temperature changed insignificantly during 6–8 μs after it reached the maximum value, which means that it ionization state can be considered as quasi-stationary.
New large-volume detector at the Baksan Neutrino Observatory: Detector prototype
Authors: Ushakov N A , Fazliakhmetov A N , Gangapshev A M , Gavrin V N , Ibragimova T V , Kochkarov M M , Kazalov V V , Kudrin D Yu , Kuzminov V V , Lubsandorzhiev B K , Lukanov A D , Malyshkin Yu M , Novikova G Ya , Petkov V B , Shikhin A A , Sidorenkov A Yu , Veretenkin E P , Voronin D M , Yanovich E A
Published: February 2021

At the Baksan Neutrino Observatory (Institute for Nuclear Research of the Russian Academy of Sciences, Moscow) deployed in the Caucasus mountains, it is proposed to create, at a depth corresponding to about 4700 mwe (meter water equivalent), a large-volume neutrino detector on the basis of a liquid scintillator with a target mass of 10 kt. This article describes the current state of the first stage of the project, namely a prototype detector with a scintillator mass of 0.5 t. The design of the detector, the equipment and methods used are described.
Seismic barriers filled with granular metamaterials: Mathematical models for granular metamaterials
Authors: Kuznetsov S I , Morozov N F , Bratov V , Ilyashenko A
Published: February 2021

The problem of seismic protection from the main types of surface acoustic waves and shear–pressure (SP) evanescent waves emanating from vicinity of an epicenter of an earthquake is discussed. Herein, SP waves represent a kind of the evanescent waves arising at critical angles of incident of bulk shear waves. The proposed seismic protection method utilizes vertical trenches (vertical barriers) filled with the specially constructed granular metamaterials. Some of nonlinear hyperelastic models along with nonlinear and inelastic models are analyzed for applications using granular metamaterials in case of cyclic dynamic loadings that correspond to arrival of the large intensity surface acoustic and evanescent waves. The main attention is paid to arrival of the large intensity Rayleigh, Rayleigh–Lamb and SP waves, as the most frequent waves and the most dangerous waves for engineering structures. Some of the new constitutive equations for metamaterials exhibiting different elastic moduli at tension and compression phases are proposed and discussed.
High performance wave packet molecular dynamics with density functional exchange-correlation term for non-ideal plasma simulations
Authors: Lavrinenko Ya S , Morozov I V , Valuev I A
Published: February 2021

We report on development of the wave packet molecular dynamics (WPMD) with density functional theory (DFT) simulation technique that we proposed earlier for nonideal plasma and warm dense matter simulations. The method is based on the WPMD where the electron exchange-correlation effects are taken into account using the DFT approach. It is aimed at studying simultaneous dynamics of electrons and ions in equilibrium and non-equilibrium conditions for a wide range of temperatures and densities. Compared to classical molecular dynamics and WPMD simulations the method of WPMD-DFT provides more accurate representation of quantum effects such as electron–ion coupling and electron degeneracy. At this stage of the method development we pay a special attention to the performance issues such as acceleration with graphical processing units, the choice of an optimal simulation box size with respect to the boundary conditions, the use of an adaptive mesh for calculation of the exchange-correlation energy, and implementation of our algorithm in the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The results for internal energy of equilibrium dense hydrogen plasma are presented for evaluation of the method.
The interaction of laser radiation with strongly coupled plasmas
Authors: Zaporozhets Yu B , Mintsev V B , Reinholz H , Röpke G
Published: February 2021

New results of measurements of s- and p-polarized reflectivity of nonideal plasma at the frequency of the external electromagnetic field ν
las = 2.83 × 1014 s−1, free-electron number density n
e = 3.3 × 1021 cm−3 (Coulomb nonideal plasma parameter Γ = 1.2) and n
e = 5.2 × 1021 cm−3 (Γ = 1.4) are presented. These data are the result of the next stage of study of optics of a warm dense matter. We present a microscopic approach to describe the entire set of experimental data on the optics of strongly correlated plasma.
Electrical conductivity of dilute colloid electrolytes
Authors: Shikin V B , Chikina I
Published: February 2021

We discuss the mechanism of the influence of the multiply-charged colloidal clusters on linear electric transport in diluted polyelectrolytes. The structure of these colloids has well known form. They are effectively neutral and cannot participate in the transfer of charges in the solution. Nevertheless, there is a linear increase in the conductivity of colloidal polyelectrolyte with an increase in the density of colloids. This phenomenon is observed experimentally. It is shown that this happens due to the change of electric field in the polyelectrolyte under the effect of colloidal particle polarization.
Analysis of micro-acceleration requirements in the context of designing a small technological spacecraft
Authors: Anshakov G P , Belousov A I , Sedelnikov A V , Taneeva A S
Published: February 2021

The paper analyzes the design features of a small technological spacecraft justifying the choice of design parameters and modeling the functioning of the spacecraft in terms of micro-acceleration requirements. These requirements are imposed in order to successfully implement gravitationally sensitive technological processes, determine the possibility and feasibility of their implementation and regulate the choice of design parameters, structural layout diagram and executive bodies of the orientation and motion control system of a small technological spacecraft. The experience of designing, creating and operating medium-class technological spacecraft is generalized and analyzed. Common points and differences are identified and discussed. The approaches proposed in the work and the results obtained can be used in the design of small technological spacecraft.
Demonstration sample research impulse of the propulsion system of nanosatellite
Authors: Blinov V N , Kositsin V V , Lukyanchik A I , Ruban V I , Stepen P V , Yachmenev P S
Published: February 2021

The aim of the research is to determine ways to create a pulse corrective propulsion systems of a maneuvering nanosatellite at the early stages of design when forming its design appearance on the basis of experimental and numerical studies of a demonstration sample with a multifunctional flow-through launch chamber and an micro resistojet of a transverse nozzle placement scheme. A pneumohydraulic scheme of a propulsion system with various chokes of a multifunctional flow-through starting chamber has been developed. Experimental and numerical studies of a demonstration sample of a propulsion system confirmed its operability and the possibility of achieving the specified characteristics by changing the interdependent main design parameters in terms of pressure, temperature, specific thrust pulses, duration of operation in various operating modes, and design parameters of a multifunctional flow-through launch chamber. Based on the results of experimental and numerical studies, a 3D model of an improved pulse propulsion system was developed.
Building a wear resistance model of drilling operation using locally adaptive regression models
Authors: Popov A A , Karmanov V S
Published: February 2021

The paper deals with building mathematical models of metal cutting processes in the context of the optimum performance problem. A new class of wear resistant models called «locally adaptive models» is proposed. A practical case solution is given.
The optimal parameters technique for the vertical ground heat exchangers of the geothermal heat pump systems
Authors: Semenov B A , Saponenko D S
Published: February 2021

A scientifically substantiated methodology for determination the optimal parameters of vertical heat exchangers of a underground circuit of the geothermal heat pump systems (GHPS) by the condition of reaching the maximum integral effect or Net Present Value (NPV) is presented. The calculations have confirmed the maximum economic efficiency of the vertical ground heat exchangers can be achieved when observing the optimal values of two defining parameters: the total length of U-shaped heat-receiving pipe and the consumption of the heat carrier passing on it. The optimal values of these parameters are calculated depending on the type and temperature of the ground, the diameter and grade of polyethylene pipes, the initial temperature of the heat carrier at the inlet, tariffs for heat and electricity, specific capital investments in all elements of the ground exchangers, including earthworks, taking into account the real discount rate and a number of additional initial data. The technique allows, to determine the optimal construction and operating parameters of vertical ground heat exchangers under various climatic conditions and types of ground. Also, this technique makes it possible to quantitatively evaluate the maximum achievable economic efficiency of using underground circuit with vertical U-shaped exchangers for the extraction of low-potential ground heat. The use of given technique is necessary for a real assessment of the feasibility of using GHPS as alternative sources of thermal energy in each case.
On the issue of selecting burned materials in rocket vehicle designs
Authors: Trushlyakov V I , Zharikov K I
Published: February 2021

The concept of selecting materials for the design of separable parts of missiles with a property that ensures their rapid disposal by burning after the mission is completed is considered. The characteristics of incinerated materials are presented. The choice of materials based on the proximity of thermal and strength characteristics to existing structural materials used in the production of traditional head fairings is made.
Study the bias field in bilayer film by computer simulation
Authors: Belim S V , Larionov I B
Published: February 2021

Computer modeling of two-layer system from antiferromagnetic and ferromagnetic films is carried out. The Ising model is used. Wolf ′s cluster algorithm is used for calculations. Phase transition temperatures are determined. A state with an ordered antiferromagnetic film and a disordered ferromagnetic film is selected for examination. Dependence the ferromagnetic film magnetization on parameters of antiferromagnetic film is determined. Computer simulation of ferromagnetic film behavior in external magnetic field is performed. The value of the anti-ferromagnetic bias field is determined from the comparison these two experiments. The dependence of the bias field on the exchange integral value at the film boundary is determined.
Research of the influence of optical fibers structure on the spectral characteristics of Mandelstam – Brillouin scattering
Authors: Bogachkov I V , Gorlov N I
Published: February 2021

Influences of structures of optic fibers, fiber types and the dopant concentration, composition, number and thickness of layers on the characteristics of Mandelstam – Brillouin backscattering are discussed. Results of modeling and experimental tests for different types of optic fibers are presented. The comparative analysis of the obtained results is carried out.
About the possibility of using speech recognition technologies in problems of assessing the protection of acoustic information from the leakage throught technical channels
Authors: Ivanov A V , Salimov Sh R
Published: February 2021

This article discusses the possibility of improving the existing instrumental calculation method for assessing the security of meeting rooms by moving from the Pokrovsky formant method to using speech recognition algorithms based on deep neural networks. In our case, it is proposed to use recurrent neural networks that have shown themselves best in terms of information processing with low SNR ratios. Also, using the long-term short-term memory of a recurrent neural network, it is proposed to improve the test signal. In addition, it substantiates the need to take into account the individual characteristics of the room and the possibility of using interference, such as a “speech choir”.
An Approach to Data Transmission Process Modelling in Automated Power Accounting Systems
Authors: Lyubchenko A A , Kopytov E Y , Malyutin A G , Bogdanov A A
Published: February 2021

An accurate accounting of electricity consumption is a relevant task for the improvement of energy efficiency both in industry and in housing and communal services. An important step in solving this task is the deployment of automated metering systems that allow obtaining analytical information required for development and adjustment of energy saving programs. The development of data transmission technologies over cellular networks has led to the widespread use of wireless channels for information exchange in automated energy control and monitoring systems. As both main and reserve communication channels, these systems can use technologies with channel switching (GSM CSD) and packet switching (GPRS). The choice of a particular data transmission technology in this case depends on a number of technical or economic factors. The aim of this work is the development of a conceptual model of the data transmission process in the automated energy consumption monitoring systems with direct connection of meters via GSM CSD and GPRS channels. For modeling the physical layer of the radio channel the model of signal propagation of Okamura-Hata was chosen. Calculation of call blocking probability is based on Erlang-B model. MIR C-01 and CET-4TM have been chosen as electric energy meters. In the work, the conceptual model of data transmission process in the monitoring system with GSM CSD and GPRS channels is offered, being a basis for its further mathematical formalization for the purpose of modelling of an information exchange between elements of the automated energy consumption monitoring system.
The problem of security address resolution protocol
Authors: Stepanov P P , Nikonova G V , Pavlychenko T S , Gil A S
Published: February 2021

This paper examines the conditions for conducting a Man in the middle (MITM) attack in networks using the Address Resolution Protocol (ARP), as well as possible methods for detecting and preventing such attacks. Examples of implementation of denial of service (DoS) attacks in a peer-to-peer network using the ARP protocol are given. An implementation of an ARP spoofing attack in Python and C # using the sharppcap library is presented. Examples of Man-in-the-middle attacks such as DHCP spoofing and ICMP redirection are provided. Describes the techniques of hacking the router and spoofing the MAC address.
Creation of a morphological analyzer based on finite-state techniques for the Uzbek language
Authors: Bakaev I I , Bakaeva R I
Published: February 2021

The article analyzes the existing morphological analyzers related to agglutinative languages. The architecture of the morphological analyzer for the Uzbek language is proposed, the functionality is described using the IDEF0 model, and a finite-state transducer for grammatical and morphological rules is created. Here also described a formal mathematical model for rules morphotactics. Based on the rules of grammar, morphotactics, morphonology, an algorithm was developed using a finite state machine and a transducer.
The dispersion complexes and prognostic tables of allergic triggers “Tree dust” construction
Authors: Goltyapin V V , Kondratieva N A
Published: February 2021

Allergy is one of the most widespread diseases in the world and its epidemic growth over the past 30-40 years is obvious. The results of numerous Russian and foreign epidemiological studies objectively reflect the steady increase in allergic pathology, including pollen allergens being one of the most common allergic triggers. About 15% of the population has the pollen affects allergy, this is one of the most common allergic diseases. Hence, it is important to construct dispersion complexes and prognostic tables to assess the impact of an allergic triggers “birch pollen + alder pollen” combination on the category of observed symptoms (“nasal congestion”, “rash”, “choking”, “itching”). To determine the effect strength on the allergic triggers combination “birch pollen + alder pollen” on symptoms, dispersion complexes were constructed. The calculations were carried out using the STIR computer system with the implementation of a computational algorithm for constructing dispersion complexes and predictive probability tables.
Curriculum optimization algorithm using genetic programming methods
Authors: Guts A K , Senkovskaya A A , Furayeva I I
Published: February 2021

Recently, optimization has become an important aspect of educational process management. The goal of the optimization process is usually reduced to reducing the total amount of the pedagogical load of the university, as well as to the formation of an optimal schedule of training sessions with the existing classroom fund. This article discusses the main aspects of the formation of curricula in order to optimize the educational process. The problem of formation of educational flows is considered with a combination of disciplines of general education and majors. A solution is proposed to optimize the curriculum in order to minimize educational flows and the total teaching load of departments using genetic programming methods.
On radicals over strict partial order sets
Authors: Nikitin A Yu , Shevlyakov A N
Published: February 2021

In this paper we deal with strict linear orders and find a poset Un
such that any radical over Un
coincides with the congruent closure of a system S which defines a poset of a height at most n.
Study of the main factors affecting the spread of aerosol particles in the atmosphere
Authors: Ravshanov N , Shafiev T R , Daliev Sh
Published: February 2021

To conduct a comprehensive study of the significant factors affecting the transfer and diffusion process of aerosol particles in the atmosphere, a mathematical model, numerical and software tools are developed in the paper. Taking into account the physicomechanical properties of harmful substances discarded from industrial production facilities and the characteristics of soil surface, air velocity, and the substance extinction coefficients. When predicting the concentration of harmful substances in the atmosphere, a key factor that affects the transfer and diffusion of aerosol particles in the atmosphere is the velocity of substance transfer in three directions x, y, z, respectively. The problem posed in the paper is solved by the finite-difference method and the results of numerical calculations on a computer are presented in the form of graphs. It was established that the transfer and diffusion processes of aerosol particles in the atmosphere that play an important role are the rate of air mass formation in the surface layer of the atmosphere; the density and linear size of the aerosol particles emitted into the atmosphere; the terrain, which generates the velocity of air propagation in the atmosphere. It was established by computational experiments that the lower the density and mass of a harmful substance particle, the higher its horizontal velocity and the lower its vertical velocity.
On direct product of algebraic sets over groups
Authors: Shevlyakov A N
Published: February 2021

We study systems of group equations of the form S = S
1 (X) U S
2 (Y), where X, Y are disjoint sets of variables. The central problem is the description of the radical Rad(S) in terms of the systems S

i
. We prove that Rad(S) may contain equations which are not derived from equations from Rad(S

i
). Systems of equations are considered in the following classes of groups: abelian, free and 2-step nilpotent groups.
Numerical research of probabilistic characteristics of quality by the piece the component of mix with increase in number of doses given by the batcher
Authors: Evseev A V
Published: February 2021

In work it is carried out the mathematical analysis of these pilot studies of the automatic conveyor mixer (non-mixer) and drum dozers for receiving mix of single elements of the components having similar standard overall dimensions but differing in internal properties at effective end use. The relevance and novelty of development are shown on the example of receiving the general party of composite product from small similar parties, at the determined forming of its uniformity, with the set qualitative and quantitative characteristics from single heterogeneous components. The analysis of influence of ratios of components in synthesizable mix on its quality is carried out. The main evaluation criterion was the quantity of doses of components at the same time given by batchers and its influence on final parameters of the received mixes.
Two algorithms for numerical modeling of thermal decay of a metastable state
Authors: Chushnyakova M V , Gontchar I I , Khmyrova N A
Published: February 2021

We compare two numerical algorithms for the computer modeling of the thermal decay process (Kramers problem) solving the stochastic (Langevin) equations for the generalized coordinate and its conjugate momentum. These are known in the literature (i) the ALGO algorithm including in the fluctuation part the terms up to τ3/2 (t is the time step of the numerical modeling) and (ii) the Euler-Maruyama algorithm including in the fluctuation part only the terms proportional to τ1/2. We concentrate on the quasistationary decay rate and transient time. The ALGO algorithm appears to be more efficient, however, the optimal size of the time step has a strong and non-trivial dependence upon the dissipation strength and governing parameter.
The experience of magnets manufacturing from metal powder using a laser
Authors: Zhukov A S , Barakhtin B K , Bobyr V V , Kuznetsov P A , Shakirov I V
Published: February 2021

The structure of hard magnetic and soft magnetic alloys manufactured on a RussianSLM FACTORY init by selective laser melting (SLM) from a spherical powder less than 80 μm in size has been studied. The powder is made by melt atomization from ingots. At various scanning speeds and laser power, additive samples were manufactured to study the structure, magnetic parameters, and also fractal analysis. According to the research results, recommendations were given on changing the melting modes and conducting thermal post-processing of materials. By constructing a hysteresis loop, data were obtained indicating the achievement of magnetic characteristics in additive samples that are close in magnitude to magnets of traditional founding technology. Prototypes of complex-shaped additive magnets have been made.
Dual-crosslinked 3D printed gelatin scaffolds with potential for temporomandibular joint cartilage regeneration
Authors: Helgeland Espen , Rashad Ahmad , Campodoni Elisabetta , Goksøyr Øyvind , Pedersen Torbjørn Østvik , Sandri Monica , Rosén Annika , Mustafa Kamal
Published: February 2021

A promising alternative to current treatment options for degenerative conditions of the temporomandibular joint (TMJ) is cartilage tissue engineering, using 3D printed scaffolds and mesenchymal stem cells. Gelatin, with its inherent biocompatibility and printability has been proposed as a scaffold biomaterial, but because of its thermoreversible properties, rapid degradation and inadequate strength it must be crosslinked to be stable in physiological conditions. The aim of this study was to identify non-toxic and effective crosslinking methods intended to improve the physical properties of 3D printed gelatin scaffolds for cartilage regeneration. Dehydrothermal (DHT), ribose glycation and dual crosslinking with both DHT and ribose treatments were tested. The crosslinked scaffolds were characterized by chemical, mechanical, and physical analysis. The dual-crosslinked scaffolds had the highest degree of crosslinking and the greatest resistance to hydrolytic and enzymatic degradation. Compared to the dual-crosslinked group, the ribose-crosslinked scaffolds had thinner printed strands, larger pore surface area and higher fluid uptake. The compressive modulus values were 2 kPa for ribose, 37.6 kPa for DHT and 30.9 kPa for dual-crosslinked scaffolds. None of the crosslinking methods had cytotoxic effects on the seeded rat bone marrow-derived mesenchymal stem cells (rBMSC). After 4 and 7 d, the dual-crosslinked scaffolds exhibited better cell proliferation than the other groups. Although all scaffolds supported chondrogenic differentiation of rBMSC, dual-crosslinked scaffolds demonstrated the lowest expression of the hypertrophy-related collagen 10 gene after 21 d. The results show that 3D printed gelatin scaffolds, when dually crosslinked with ribose and DHT methods, are not toxic, promote chondrogenic differentiation of rBMSC and have potential application in tissue engineering of TMJ condylar cartilage.
Environmental Influence Analysis of Global Gravity Anomaly Gradient Basing on Neighbourhood Satistics in GIS
Authors: Yang Chunlin
Published: February 2021

A series of abnormal environmental phenomena were found related with local earth gravity field anomaly through statistics and calculation analysis. Gravity anomaly gradient was used to describe gravity anomaly change in local extent. Total of 79% in earth surface gravity anomaly gradient express stable (<30 mGal/Degree), 7.37% area express major gravity anomaly gradient (> 50 mGal/Degree), of 3.43% area gravity anomaly gradient is very high (> 70 mGal/Degree). While gravity anomaly is over 30 mGal/Degree, there will may more easily appear sandstorm, tornadoes and haze weather, if thermodynamic conditions and material conditions are proper. Many natural disasters start from these areas, where gravity anomaly gradient is very high.
The Environmental Rehabilitation Research for Manhole Covers on City Roads
Authors: Cai Sonbai , He Feng , Li Dazhi , Zhu Peijuan , Liu Xiongfei , Chen Zheng
Published: February 2021

In order to facilitate inspection and maintenance for municipal public pipelines located below urban roads, more and more manholes were set up on the road surfaces. However, due to various inadequate design and construction etc., the manhole suffered most serious diseases such as collapse of wellhead, broken up of pavement around well, subsidence of manhole and damage of internal well structure. Which not only harms its life span, but also affects the driving safety and the city appearance. Firstly, this work investigated the manhole diseases of typical roads in cities of Changsha etc. and concluded that there are only two main types of road manhole diseases. The most prominent one is the pavement damages. The second one is the wellhead subsidence greater than 20mm. Secondly, the main causes of manhole disease was found out from the aspects of both design and construction. In design, the lack of details of wells and its surrounding backfill materials are main causes. In terms of construction, there are many problems such as insufficient attention to quality control, inadequate operation of key processes and lower level of construction refinement. Finally, systematic and comprehensive measures to deal with various kinds of diseases of manhole in not only design and construction but also prevention and restoration were presented.
The Research of the Automobile Industry in Wuhan on the Context of New Technology, New Energy and Intelligentization
Authors: Liu Quanhong , Wang Hongping , Peng Yun
Published: February 2021

Nowadays, China’s automobile manufacturing industry has developed rapidly and the overall quality has been steadily improved. After several years of rapid development, with the continuous progress of technology, new energy and intelligent technology began to popularize. However, the production and sales of self-owned brand passenger cars have shrunk greatly due to the decline of overall sales of passenger cars. As the headquarters of Dongfeng Motor Group, Wuhan has certain cluster advantages in R&D of self-owned brand vehicles, but it has been in a loss state in recent years, and there is an obvious gap between Wuhan and the first-line self-owned brands. Therefore, it is worth discussing how to seize the development opportunity, promote the quality of its brand and become a first-line brand. This paper analyses the development status, challenges, and bottlenecks of Wuhan self-owned automobile brand quality improvement under the development background of new technology, new energy and intelligent, and puts forward the strategy of Wuhan self-owned automobile brand quality improvement. This paper suggests that we should strictly implement the automobile quality regulations, establish the quality assurance and traceability system of self-owned brands, increase the support of new energy sources for self-owned brands and the development of intelligent car service, and build a quality basic technology sharing platform, so as to achieve the purpose of improving the quality of Wuhan’s self-owned automobile brands.
Investigation on Runaway Process in Power Generation Device: Tubular Turbine Based on IB-LBM Method
Authors: Tian Diyang , Zhu Guojun , Feng Jianjun , Ge Zhenguo , Li Wenfeng , Li Yunzhe
Published: February 2021

The immersed boundary lattice Boltzmann method (IB-LBM) was applied to numerically simulate the runaway process of tubular turbines with the influence of the free surface of upper and lower reservoirs. First, the accuracy of the IB-LBM method was verified, and then the external performance and internal flow characteristics of units during runaway process were studied. The results show that the gravity causes uneven pressure distribution at inlet of the turbine with considering the influence of the free surface of the reservoirs, resulting in complicated flow pattern, which cannot be ignored in the study. In the course of runaway, low-pressure area of draft tube changes periodically with a certain degree of cavitation occurring on pressure and suction surface of the blades, which threatens the overall operation stability of the unit.
Navigating across multi-dimensional space of tissue clearing parameters
Authors: Avilov Sergiy V
Published: February 2021

Optical tissue clearing refers to physico-chemical treatments which make thick biological samples transparent by removal of refractive index gradients and light absorbing substances. Although tissue clearing was first reported in 1914, it was not widely used in light microscopy until 21th century, because instrumentation of that time did not permit to acquire and handle images of thick (mm to cm) samples as whole. Rapid progress in optical instrumentation, computers and software over the last decades made micrograph acquisition of centimeter-thick samples feasible. This boosted tissue clearing use and development. Numerous diverse protocols have been developed. They use organic solvents or water-miscible substances, such as detergents and chaotropic agents; some protocols require application of electric field or perfusion with special devices. There is no ‘best-for-all’ tissue clearing method. Depending on the case, one or another protocol is more suitable. Most of protocols require days or even weeks to complete, thus choosing an unsuitable protocol may cause an important waste of time. Several inter-dependent parameters should be taken into account to choose a tissue clearing protocol, such as: (1) required image quality (resolution, contrast, signal to noise ratio etc), (2) nature and size of the sample, (3) type of labels, (4) characteristics of the available instrumentation, (5) budget, (6) time budget, and (7) feasibility. Present review focusses on the practical aspects of various tissue clearing techniques. It is aimed to help non-experts to choose tissue clearing techniques which are optimal for their particular cases.
A thermophysically balanced multiscale coarse-grained potential for glass-forming polymers with the energy renormalization method
Authors: Jung Jiwon , Park Chanwook , Yun Gun Jin
Published: February 2021

Coarse-grained molecular dynamics simulations are a widely accepted methodology in the field of studying the viscoelasticity of elastomers. In this paper, a thermophysically balanced multiscale coarse-grained potential for glass-forming polymers is presented with the energy renormalization (ER) method by redefining temperature transferable correlation effects between rescaling factors for energy parameter and length-scale parameter. The correlation effects have not been investigated in the literature, to the best knowledge of authors. The coarse-grained potential was demonstrated for the polyisoprene model generated from the anionic polymerization. The ER enables temperature transferability by adopting renormalization parameters as function of the temperature. Considering the correlation effects, a multi objective-optimization algorithm was adopted to find proper solution sets of

α

and

β

matching mean square displacement (MSD) and density to the all-atom model simultaneously. Meanwhile, shear stress was matched to find

α

first, then, density was fitted in the low-temperature regime. To verify the coarse-grained potential in the middle-temperature regime, MSD was compared to those from the all-atom model, and it was successfully matched.
Deep learning super-diffusion in multiplex networks
Authors: Leli Vito M , Osat Saeed , Tlyachev Timur , Dylov Dmitry V , Biamonte Jacob D
Published: February 2021

Complex network theory has shown success in understanding the emergent and collective behavior of complex systems Newman 2010 Networks: An Introduction (Oxford: Oxford University Press). Many real-world complex systems were recently discovered to be more accurately modeled as multiplex networks Bianconi 2018 Multilayer Networks: Structure and Function (Oxford: Oxford University Press); Boccaletti et al 2014 Phys. Rep.
544 1–122; Lee et al 2015 Eur. Phys. J. B
88 48; Kivelä et al 2014 J. Complex Netw.
2 203–71; De Domenico et al 2013 Phys. Rev. X
3 041022—in which each interaction type is mapped to its own network layer; e.g. multi-layer transportation networks, coupled social networks, metabolic and regulatory networks, etc. A salient physical phenomena emerging from multiplexity is super-diffusion: exhibited by an accelerated diffusion admitted by the multi-layer structure as compared to any single layer. Theoretically super-diffusion was only known to be predicted using the spectral gap of the full Laplacian of a multiplex network and its interacting layers. Here we turn to machine learning (ML) which has developed techniques to recognize, classify, and characterize complex sets of data. We show that modern ML architectures, such as fully connected and convolutional neural networks (CNN), can classify and predict the presence of super-diffusion in multiplex networks with 94.12% accuracy. Such predictions can be done in situ, without the need to determine spectral properties of a network.
Largest acylindrical actions and Stability in hierarchically hyperbolic groups
Authors: Abbott Carolyn , Behrstock Jason , Durham Matthew
Published: February 2021

We consider two manifestations of non-positive curvature: acylindrical actions (on hyperbolic spaces) and quasigeodesic stability. We study these properties for the class of hierarchically hyperbolic groups, which is a general framework for simultaneously studying many important families of groups, including mapping class groups, right-angled Coxeter groups, most

3
3

–manifold groups, right-angled Artin groups, and many others.

A group that admits an acylindrical action on a hyperbolic space may admit many such actions on different hyperbolic spaces. It is natural to try to develop an understanding of all such actions and to search for a “best” one. The set of all cobounded acylindrical actions on hyperbolic spaces admits a natural poset structure, and in this paper we prove that all hierarchically hyperbolic groups admit a unique action which is the largest in this poset. The action we construct is also universal in the sense that every element which acts loxodromically in some acylindrical action on a hyperbolic space does so in this one. Special cases of this result are themselves new and interesting. For instance, this is the first proof that right-angled Coxeter groups admit universal acylindrical actions.

The notion of quasigeodesic stability of subgroups provides a natural analogue of quasiconvexity which can be considered outside the context of hyperbolic groups. In this paper, we provide a complete classification of stable subgroups of hierarchically hyperbolic groups, generalizing and extending results that are known in the context of mapping class groups and right-angled Artin groups. Along the way, we provide a characterization of contracting quasigeodesics; interestingly, in this generality the proof is much simpler than in the special cases where it was already known.

In the appendix, it is verified that any space satisfying the a priori weaker property of being an “almost hierarchically hyperbolic space” is actually a hierarchically hyperbolic space. The results of the appendix are used to streamline the proofs in the main text.
Cuban Racial Politics in Nineteenth-Century New York: A Critical Digital Approach
Authors: Hoffnung-Garskof Jesse
Published: February 2021

This essay offers a reappraisal of the racial politics of the nineteenth-century Cuban independence struggle through an analysis of the experience, as migrants, of Rafael Serra and other Afro-descendant activists in New York. Serra was the leader of a community that worked with José Martí to create the Cuban Revolutionary Party (PRC). The author makes use of digital tools for network visualization and mapping to illustrate the evidence of both race-based (diasporic), class-based, and nationalist social networks among Serra’s constituents. These networks, created against a backdrop of highly localized residential segregation, facilitated a range of political strategies including the creation of race-based organizations, alliances with African Americans, and the more famous cross-racial coalitions of the PRC. Such strategies were not mutually exclusive, as has sometimes been presumed, but rather mutually dependent. In presenting this evidence, the author responds to recent work by Putnam on research “in the digital age” and follows Solberg’s call on digital humanities scholars to “give away our game,” presenting a critical self-appraisal of the digital methods, tools, and labor arrangements employed. Following Tufte and Theibault, he concludes that digital visual representations are useful to humanities scholars not because they generate or validate arguments, but because they can effectively illustrate arguments that rest on humanistic systems of analysis and evidence.
Slow History
Authors: Lindemann Mary
Published: February 2021

All historians realize how much COVID-19 has interfered with our scholarship and teaching. Everything has slowed down, from preparing for classes, to doing research, to completing the simplest tasks of everyday life. Yet in the upheaval we are currently experiencing, and as we struggle to remain productive, perhaps we should also seize the opportunity to think more deeply about the “doing” of history and to isolate what really matters in research, writing, and instruction. Scholars in other disciplines have been doing so for several years, and some have even issued manifestos like the one advocating for “slow science.” Should we follow their lead? “Is going slow good for historians as well?”
Nonsurgical Correction of Secondary Contour Deformities of the Penile Girth
Authors: Yordanov Yordan P
Published: February 2021

Background

Dealing with remaining penilе deformities following surgery to correct complications after injection of nonabsorbable substаnces tends to be troublesome. There is a lack of adequate information regarding the options for the management of such residual irregularities. In morе than 2 decades of clinical application, hyaluronic acid (HA) fillers have proved to be a safе and reliable solution fоr a great variety of age-related changes, tissue atrophy, and contour deformities.

Objectives

This brief clinical study aimed to demоnstrate the author’s initial еxperience with the novel use of an HA-based filler for the correction of secondary deformities of penile girth.

Methods

Rеtrospective analysis was conducted, encompassing patients who underwent correction of secondary penile deformities with HA between August 2018 and February 2020. Тhe procedures were carried оut in an ambulatory setting and a blunt cannula was used for filler infiltration. A 9-month follow-up was established.

Results

Five patients aged between 29 and 44 years (average, 35.8 years) were found and included in the study. The mean volumе of HA product used for the correction was 3.32 mL. An analysis of the outcomes demonstrated a high satisfaction ratе among pаtients with no complications in thе series.

Conclusions

The procedure is safe, effective, and relatively simple with reproducible and reliable outcomes. Due to its excellent spreading and good tissue integration, the selected HA filler was very useful in cases where fibrosis was present because of previous surgeries.

Level of Evidence: 4