bluuebunny/crossref_metadata_2025 huggingface dataset:
Force Analysis of Supporting System during Form-Work Construction of Box Culvert without Tie Rod
Authors: Zhai Guangming , Wang Yuwei , Liu Liu , Guo Pan
Published: January 2022

In the construction process of box culvert form-work without tie rod, the stress state of its supporting system is of great importance. Based on a construction project for the box culvert without tie rod form-work, this paper studied the force characteristics of diagonal braces during the concrete pouring of the box culvert. The force calculation theory of the support system was analyzed and the force was analyzed using the finite element software Midas Civil. The results showed that when the distance between the connection point of the diagonal brace and the foundation was 1 m, the diagonal brace cannot provide effective support for the template, and when the distance between the connection point of the diagonal brace and the template is 2 m, 3 m, and 4 m, the diagonal brace can provide effective support. It was recommended that the diagonal brace connection point is 3 m away from the template as the optimal diagonal brace layout position. It is recommended to strengthen the area of increased local deformation of diagonal braces to a certain extent according to the calculation results of this finite element analysis to improve the safety performance of the entire structure. The research results of this paper can provide reference for follow-up similar construction problems.
Study on Self-Cleaning Time and Suspended Particle Distribution in Medical Clean Room
Authors: Chen Long , Wang Enyan , Li Yang , Weng Miaocheng , Liu Fang
Published: January 2022

CFD numerical simulation of clean room in Class D medical factory was carried out and compared with the actual measurement to verify the feasibility of the simulation method. On this basis, four typical air flow organizations were simulated and compared by changing air change rate from two directions of self-cleaning time and suspended particle concentration field. According to the simulation results, in order to meet the self-cleaning time within 20 min, the best air change rate should be between 15/h and 25/h. Different air flow organizations have different self-cleaning capacity, and the value of air change rate can be relatively small in the form of single-side supply same-side down return. Different airflow organizations have different suspended particle distribution characteristics, and there are differences in the applicable scenarios, and the applicability of the top supply down return is the best.
Quantitative Identification Cracks of Heritage Rock Based on Digital Image Technology
Authors: Wang Xiufang , Li Jingyuan , Bai Ming , Pei Yan
Published: January 2022

Digital image processing technologies are used to extract and evaluate the cracks of heritage rock in this paper. Firstly, the image needs to go through a series of image preprocessing operations such as graying, enhancement, filtering and binaryzation to filter out a large part of the noise. Then, in order to achieve the requirements of accurately extracting the crack area, the image is again divided into the crack area and morphological filtering. After evaluation, the obtained fracture area can provide data support for the restoration and protection of heritage rock. In this paper, the cracks of heritage rock are extracted in three different locations.The results show that the three groups of rock fractures have different effects on the rocks, but they all need to be repaired to maintain the appearance of the heritage rock.
Impact of Lightning Protection Grounding System on the Ground Surface Potential of Substations
Authors: Chen Tingji , Yang Lian , Gu Weibing , Gao Haiyang , Zhou Junchi , Fu Xiaodong
Published: January 2022

Grounding device is an indispensable facility for lightning protection of buildings. Nowadays, SGCC (State Grid Corporation of China) is promoting steel structure substations, which are made of metal as a whole including the roof. There are now several grounding approaches when the roof was struck by a lightning flash, including external grounding, nearby grounding, separate grounding and common grounding. This paper took a metal structure substation in Nanjing as an example and calculated its ground potential in case of different grounding system. We came to such conclusions: 1) For substations of separate grounding system, the ground potential after a lightning strike could reach as high as 743.5kV and 230kV with a single earthing electrode and multiple electrodes respectively. 1000μs after the strike, the ground potential is 91.57 kV, which is still a significant threat to humans and equipment inside. 2) Nearby grounding and external grounding are both common grounding system. The peak of ground potential after a lightning strike is 101.4kV and 109kV respectively, much lower than that of separate grounding system. They also have similar waveform and peak time. 3) 3500μs after the lightning strike, the ground potential all over the grid is around 36V. 4) Separate grounding is not a sound choice of grounding system for steel structure substations. From the perspective of cost and discharging capacity, nearby grounding is the most reasonable scheme for a steel structure substation.
Study on Temperature Control of Gravity Anchorage without Cooling Water
Authors: Xu Hanzheng , Yin Yazhou , Xu Kaihan , Li Chongjin
Published: January 2022

This paper uses Midas Fea simulation software to analyze the hydration heat of a suspension bridge anchorage mass concrete construction without cooling water. According to specific boundary conditions and convection coefficients, the concrete heating process and cooling process are simulated. Analyze the influence of surface air convection coefficient on the surface tensile stress of the cast layer, and the influence of the pouring interval on the interlayer stress of the anchor block, and the temperature difference between the inside and outside of the concrete when the anchor block is layered. It is found that reducing the surface convection coefficient of the pouring layer can effectively improve the stress condition, and the pouring interval has little effect on the stress.
An Analysis of Slope Stability Based on Finite Element Method and Distinct Element Method
Authors: Xu Bowen , Liu Shijie , Wang Jing
Published: January 2022

The analysis of slope stability involves complex geological and topographical boundary conditions, nonlinear behavior of material stress-strain, coupling analysis of initial in-situ stress, water pressure and seismic load, etc., and in most cases, analytical solutions cannot be obtained. Under the background of the continuous development of computer and calculation method, the numerical analysis method represented by finite element has been gradually popularized and applied in geotechnical engineering in 1970s, and has developed into a powerful calculation and analysis tool. Among them, the finite element strength reduction method and the discrete element method are the two most widely used slope numerical analysis methods. In this paper, two typical cases, Ankang reservoir landslide and Wenma Highway slope, are simulated by the two methods.

Taking Ankang reservoir landslide as the research object, this paper would use MIDAS / GTS finite element analysis software, and two-dimensional finite element numerical simulation would be carried out to study the influence of reservoir water level periodic fluctuation on the reinforcement effect of anti-slide pile. Under the condition of water saturation and water loss cycle, main material of landslide body and landslide belt, namely the strong weathered phyllite, displays obvious deterioration phenomenon, showing the trend of rapid decline first and then slow decline; after the anti-slide pile is set in the middle and front of the slope, the stability of it has been greatly improved, but with the increasement of the number of water level changes, the reinforcement effect of the anti-slide pile continues to weaken, and the weakening speed is fast at first, and then slows down.

Taking the bedding slope of Wenma Highway as the research object, this pater would adopt UDEC discrete element software to simulate the deformation and failure process of the slope after excavated, and analysize the failure mechanism at the same time. The failure process of bedding slope can be divided into four stages: the formation of tension cracks caused by excavation, the expansion of cracks and the formation of deformation body, the sliding of deformation body and the accumulation of damaged rock mass at the foot of slope. Tensile failure is the main failure mode, and shear failure occurs locally. The failure of bedding slope starts from the foot of slope, which is traction sliding.
Experimental Investigation on Influence of Molding Methods on Properties of Pervious Concrete
Authors: Li Qiuxiang , Zheng Jie , Fu Mingfu
Published: January 2022

Despite the common use of pervious concrete (PC), there is no standard way of producing the test specimens, which undergo testing to infer the behaviour of PC in the field. Vibrating table is the most common method but greatly reduced in vibration time compare with normal concrete in the laboratory. Marshall compaction and superpave gyratory compactor (SGC) are recommended standard molding methods for porous asphalt mixtures manufactured in the laboratory environment. Three kinds of pervious concrete samples with three target porosities were prepared by the above three methods, and the effects of the molding method on the physical properties, mechanical properties and durability of the samples were investigated in the study. Experimental results showed, with different molding methods adopting, pervious concrete with the same mixture design exhibits slightly different physical and mechanical properties. After analysis and comparison, SGC is the best choice to obtain concrete with high permeability, good freeze-thaw resistance and high strength, followed by Marshall compaction molding, and vibration molding is the last one. As a result, a win-win situation of the hydraulic characteristics and mechanical properties of pervious concrete can be achieved due to both optimized mix-design and appropriate molding method.
CFD Study on the Air Temperature Field inside Fire-Rated Duct of Pressurisation System
Authors: Yin Hang , Tan Longfei
Published: January 2022

Avoiding overheating of the supply air inside the fire-rated duct of pressurisation system is crucial for the escape and rescue of the building occupants during the development of a fire. The simulation scenarios are established concerning three cross-sectional dimensions of ducts and four inner air velocities. Based on the performance criteria of insulation specified in the international standard of ISO 834-1, the temperature fields of supply air inside different fire-rated ducts and corresponding safety are analysed based on the assumption that the exterior of fire-rated ducts is in a consistent state of being subjected to fire.
Review of Research on Physical and Mechanical Properties and Engineering Application of Metal Tailings
Authors: Wang Shengfu , Yan Lechen , Xue Kaixi , Lv Liang , Zhang Dongjie , Li Dongwei
Published: January 2022

Processing and storage requirements for metal residues are becoming stricter to achieve the carbon neutralization target. The physical and mechanical properties of tailings affect the stability of tailing dams. Metal tailings can be used as secondary resources, and it is easy to pollute the environment under poorly managed conditions. Therefore, it is necessary and urgent to reuse these deposits such as iron tailings, copper tailings, zinc tailings et al. This article discusses the current research on the mechanical properties of metal tailings and its engineering application. Based on previous research, it is pointed out that there still needs more attention on the mechanical properties of metal tailing sands, especially under different conditions like dry-wet, freeze-thaw, dynamic loads and large-scale application. In the future, research on the filling of metal tailings as roadbed and new building materials will be one of the directions to solve the problem of tailing pond accumulation.
Soil Pressure and Deformation Analysis of Small Size Deep Foundation Pit
Authors: Long Zhao , Shi Yilei , Li Weili , Ye Shuaihua
Published: January 2022

In this paper, the influence of space effect on soil pressure and deformation of deep foundation pit was considered, and the finite soil pressure calculation model was established. The soil pressure of deep foundation pit was calculated by assuming the slip surface and using the finite soil limit equilibrium theory. Then, PLAXIS 3D finite element software was used to establish finite element models of different plane sizes and depths. The distribution regulation of side wall soil pressure and deformation of deep foundation pit was calculated. Finally, the results of finite soil pressure calculation was compared with finite element method. The results shown that: The soil pressure of small deep foundation pit was affected by space effect, and the soil pressure and deformation decrease significantly along the foundation pit depth. Shear fracture Angle was related to the ratio of width to depth of foundation pit, and it was no longer a constant value of 45°+φ/2. Therefore, the spatial effect should be considered in the calculation of soil pressure of small deep foundation pit. The research results can provide some guidance for the design and calculation of similar small size deep foundation pit.
Overview of Calculation Methods of Structural Time-Dependent Reliability
Authors: Luo Lisheng , Xie Xinran , Zhang Yongqiang , He Wenyuan
Published: January 2022

Under the action of natural erosion, the strength, durability and other safety performance of structures and elements gradually decrease with time, which has a great impact. To solve the above problem, a series of time-dependent reliability analysis methods were proposed. Based on different structural performance functions, this paper analyzes and discusses different time-dependent reliability theories, including outcrossing-based reliability method, Monte Carlo simulation method, extremum method and other new methods proposed in recent years, which provides reference for later research.
A possible predictive mathematical model for the growth of a periphytic alga
Authors: Agredo J , Cárdenas-Poblador J , Ortiz-Moreno M L , Vega-Moreno A
Published: January 2022

Algae are photosynthetic organisms and have qualities that are very attractive for cultivation and industrial development for commercial purposes. When algal growth is analyzed for the production of biomass usually only the exponential phase of the growth curve is considered and the other phases are ignored. The objective of the work is to present a possible predictive mathematical model that allows a better understanding of the kinetic behavior of a periphytic microalgae by means of the use of the Smoluchowski discrete equation, with special emphasis on the lag phase. More specifically, unknown connection between the discrete Smoluchowski equation and the deterministic Baranyi model is shown in the present study. Analysis of this connection leads to a possible predictive mathematical model about of the kinetic behavior of a periphytic microalgae.
Piezoelectric mathematical modeling; technological feasibility in the generation and storage of electric charge
Authors: Camargo-Chávez J E , Arceo-Díaz S , Bricio-Barrios E E , Chávez-Valdez R E
Published: January 2022

Emerging technologies are efficient alternatives for satisfying the growing demand for sustainable and cheap energy sources. Piezoelectrics are one of the most promising energy sources derived from emerging technologies. These materials are capable of converting mechanical energy into electricity or vice versa. Piezoelectrics have been used for almost a hundred years to generate electrical and sound pulses. However, the use of piezoelectrics for power generation is constrained by the cost associated with equipment and infrastructure. This problem has been addressed through mathematical models that relate the physical and electrical properties of the piezoelectric material with the voltage generated. Although these models have high performance, they do not incorporate voltage rectification and electrical charge storage stages. This work presents a mathematical model that describes the relationship of the physical and electromechanical properties of a system employing a piezoelectric for energy generation. The voltage of the system and the charge stored in a capacitor are calculated through this model. Also, contour diagrams are presented as a tool for facilitating the efficiency of energy generation.
Meaning of the derivative as a rate of change through a graphic argumentation. A case with Chilean students
Authors: Pinto-Vergara A , Soto D , Gaete-Peralta C
Published: January 2022

From the socio-epistemology perspective, the teaching of the derivative is problematized due to the lack of reference frameworks that give variational meanings to the derivative and allow its construction by means of graphical arguments. The objective of this research was to analyze the construction of meanings of the derivative, as a rate of change, that Chilean students developed through a graphic argumentation in a specific situation of variation. In order to respond to the stated objective, a qualitative methodology was used, consisting of a case study, where a situation of variation was designed with the purpose of promoting the analysis of temperature changes in specific everyday life phenomena. This design was applied to ten Chilean high school students interested in studying engineering. As a result of the research, it was obtained that the participants, through a graphic argumentation, understood the slope of a straight line as a rate of change of temperature regarding time. It was concluded that this research provides elements for the construction of frames of reference that signify the derivative, as a rate of change, in situations of variation, valuing the graphic arguments and functional justifications that emerged from the students.
Inquiry-based learning. Beliefs of trainee teachers in a physics course
Authors: Pabón-Galán C A , Hernández-Suarez C A , Paz-Montes L S
Published: January 2022

The teaching of physics should be supported by practical or laboratory activities that seek to develop the scientific competencies of the students who study physics, so it is necessary to propose innovative strategies, such as research-based learning, in which students answer research questions through the analysis of data, which increases the interaction between the student and the physical concepts under investigation. Therefore, the objective of the study was to analyze the beliefs of teachers in natural science training at a public university in Colombia who take the subject of physics on research-based learning, to provide information on how to guide the use of innovative strategies. The study responds to a type of quantitative research with a descriptive approach and was based on a field design. On the other hand, the results reflect slightly positive beliefs of students in initial teacher training who study physics about research-based learning as an innovative strategy, although it is recommended to expand the sample to generalize. Finally, the analysis reveals as a conclusion that the implementation of innovative methodologies such as inquiry-based learning for science teaching, especially physics, should be promoted and supported more effectively to foster motivation, skills development, and conceptual understanding. of the scientific contents.
Flora of meadow communities of the Uryumkan Nature Reserve (Transbaikalia)
Authors: Makarov V P
Published: January 2022

The floristic composition of meadow communities of the valley of the Uryumkan River at the territory of the Uryumkansky nature reserve in Zabaykalsky krai was studied. The flora of meadows is characterized by significant participation of species of the genus Sanguisorba and other medicinal plants used in medicine. The meadows are very attractive and can be used as an educational object for tourist excursions.
Thermodynamics of the evolution of the biosphere
Authors: Ptitsyn A B
Published: January 2022

The thermodynamic foundations of the evolution of the biosphere are considered: the variability of natural systems with different dispersion of their components, the alternative ways of development of such systems, the alternative of intermediate stable states of ecosystems depending on fluctuations of external factors, primarily climate. The necessity of developing a system of mutually agreed complex indicators of this process is postulated. The necessity of including the water content of ecosystems in the number of parameters of nonequilibrium thermodynamics is justified. A new section of land hydrology is formulated -the study of thermodynamic aspects of the dynamics of natural waters.
UAV survey of sand knolls in the Tsasucheysky Bor Nature Reserve
Authors: Zima Y V , Banshchikova E A , Zhelibo T V
Published: January 2022

The paper examines development of sand knolls under the influence of climatic and anthropogenic factors in Southern Zabaykalye within the territory of Tsasucheysky Bor nature reserve. The sand knolls were studied on-site with instruments and aerial surveying. Grain size distribution of the soil cover was studied. The floristic composition of the sand knolls represented by motley grass-grasses and herbs-grasses steppe communities with varying degrees of projective cover was investigated. The analysis of the field survey data from an unmanned aerial vehicle (UAV) made it possible to obtain the main morphometric parameters of the sand knolls, and overlaying aerial photographs on historic satellite images allowed to trace how they changed in time. The studies showed that the movement of the studied sand knolls with time as Aeolian formations under the influence of wind erosion is unlikely, as the sand knolls are currently mostly covered by steppe vegetation, and only about 20% of the areas are bare. The analysis of satellite images and aerial photographs showed that over the last twenty years the sand knolls had not moved or changed their size.
Assessing potential hazard of technogenic formations of natural and man-made complexes of some sulphide deposits of the Eastern Zabaykalye
Authors: Tsyrenov T G
Published: January 2022

The analysis of chemical composition of technosol and soil samples from Akatuyevsky and Blagodatsky polymetallic deposit mines of the Eastern Zabaykalye revealed that the main pollutant in the soil samples is As. Material excess of the Maximum allowable concentrations was registered for Pb, Zn, Cd and Mn. Calculation of potential hazard coefficients showed that the most hazardous for the environment are man-made formations of Akatuyevsky and Blagodatsky mines. Of all the chemical elements which are most commonly encountered at the Akatuyevsky and Blagodatsky mines technosol the most hazardous are As, Pb, Zn and Cu. It is noted that these chemical elements are part of sulphide ore minerals.
On the problem of cognition of mineralogy and geochemistry of the landscape of mining territories
Authors: Yurgenson G A
Published: January 2022

A methodology for studying the forms of finding chemical elements in the landscape of mining territories is given. The necessity of mineralogical and geochemical integration of methods is shown, the influence of the forms of occurrence of chemical elements in the landscape on the extent of their absorption by biota, in particular, the coefficient of biological absorption. The dependence of the forecast of the state of mining geosystems on the forms of presence of potentially hazardous chemical elements in them is determined.
Study heat exchange in porous structures
Authors: Genbach A A , Beloev H I , Bondartsev D Yu , Genbach N A
Published: January 2022

This paper shows the problem with heat exchange depending on units of thermal power plant equipment. The type of structures is determined and the heat flow for different pressures is proposed. Studies are developed for the condition of the heat exchange surface. Devices with porous coatings eliminate the development of cracks in the components and units of TPP equipment have been suggested. The research is applicable to gas turbine units of TPP. Comparable capillary-porous and flow systems have high reliability, but the former allowed the reduction of coolant consumption dozens up to 80 times. The results show that at higher heat loads it is suitable to use in porous surfaces to control the cooling surface. Evaluation of capillary-porous structures has shown their advantages over traditional cooling systems.
Analysis of methods for assessing the energy efficiency of data centers using the power usage effectiveness method
Authors: Uanov R , Begimbetova A S
Published: January 2022

The article deals with the analysis of methods for assessing the energy efficiency of data centers according to the Power Usage Effectiveness method. The demand for data centers which consumes a large amount of electricity is growing with the growth of digitalization and the accumulation of big data in the network. The energy consumption of the cooling system for the machine room accounts for a significant part of the operating costs of the building. Free cooling in a refrigeration system reduces energy consumption much more than operating systems with a vapor-compression cycle. In 2006 according to The Green Grid, the assessment method of Power Usage Effectiveness has become an international standard for measuring energy efficiency and is widely used in the design and operation of data centers. In this regard, the operation principles of free-cooling chillers are considered. The calculation example of the system payback in free-cooling is also given.
Models and methods of digital mechanisms in anti-corruption, their advantages and disadvantages, and applications
Authors: Nurkey A , Mukasheva A , Yedilkhan D
Published: January 2022

Corruption is one of the main problems in many developing countries. However, the complexity of measuring corruption and its consequences does not allow for its complete study and implementation of measures. The factors and indicators currently known worldwide cannot measure corruption on time scales and depend on a narrow circle of experts in this area. Thus, corruption is easily confused with institutional gaps. In modern society, where the technologies such as Data Science and Predictive Analytics play a huge role, corruption is still omnipresent. The article examines the priority areas of combating corruption using new digital technologies. The main direction of the article is defined as an analysis of the advantages and disadvantages of the digitalization in the areas of solving social conflicts. The article presents the comparative analysis of technologies of digital anti-corruption compliance in developing countries, on the example of Kazakhstan. At the same time, according to the results, the article discusses the disadvantages of using proposed models due to the peculiarities of the legislation.
Junction temperature measurement in optically-activated power MOSFET
Authors: Rao Sandro , Mallemace Elisa D , Casalino Maurizio , Cocorullo Giuseppe , Dehimi Lakhdar , Della Corte Francesco G
Published: January 2022

The temperature-dependent optical properties of silicon carbide (SiC), such as refractive index and reflectivity, have been used for a direct monitoring of the junction temperature of a power MOSFET. In particular, the optical response of a 4H–SiC MOSFET-integrated Fabry–Perot (FP) cavity to temperature changes has been investigated through parametric optical simulations at the wavelength ofλ= 450 nm. The reflected optical power exhibited oscillatory patterns caused by the multiple beam interference for which the MOSFET epilayer, between the gate-oxide and the doped 4H–SiC substrate, acts as a FP etalon. These results were used to calculate the refractive index change and, therefore, the optical phase shift of Δϕ=π/2 corresponding to a temperature variation that can be considered as a warning for the device ‘health’. In practical applications, the periodic monitoring of the optic spectrum at the interferometric structure output gives an essential information about the device operating temperature condition that, for high power operations, may lead to device damages or system failure. Moreover, the optical monitoring of the junction temperature has been combined with the optical activation of the same device in order to design an all-optically controlled power MOSFET. Electro-optical simulation results show that the application of an UV optical beam (λ= 285 nm) leads to the creation of the electrical channel between drain (D) and source (S). The corresponding current density–voltage (JD–VDS) characteristics have been calculated under different values of the optical power density up to 10 kW cm−2.
Generation and evolution of vortex array with variable-ratio lateral-shearing interferometry
Authors: Li Yong , Zhang Junyong , Li Jianlang
Published: January 2022

Different from the method by plane-wave interference, here an efficient approach is proposed to generate optical vortex array (VA) based on lateral-shearing interferometer, in which the evolution from light spot array to VA can be observed by continuously variable shear ratio in a certain range. VAs with topological charge 2 and 1 are simulated by software GLAD and proved to be effectiveness through optical experiment. Theoretical analysis and experimental results show that when the shear ratio approaches to zero, we can stably obtain a VA with high density and variable topological charge.
Broadband reflectors with a disordered layered structure: statistical properties of high performing configurations selected via genetic algorithm
Authors: Fiumara Vincenzo , Addesso Paolo , Chiadini Francesco , Scaglione Antonio
Published: January 2022

Disordered multilayers consisting of alternating layers of two lossless dielectric materials with random thicknesses can behave as good reflectors in wide wavelength ranges except for narrow bands where the transmittance is significative. We use a dedicated genetic algorithm to select different configurations (thickness sequences) of such structures which exhibit very low transmittance in the entire visible wavelength range, showing that broadband disordered reflectors with very high performance can be designed. A statistical analysis of the thickness sequences selected by the genetic algorithm reveals that such sequences are characterized by correlated disorder and that the degree of autocorrelation is a key parameter in determining the reflection performance.
Optical image encryption scheme with extended visual cryptography and non-mechanical ptychographic encoding
Authors: Yu Han , Li Yong , Zhang Junhao , Yang Dongyu , Ruan Tianhao , Wang Huaying , Shi Yishi
Published: January 2022

Non-mechanical ptychographic encoding (NPE) transforms the secret information into series of diffractive patterns through a spatial light modulator (SLM), saving the need to fabricate the secret objects. Conventionally, the shares in extended visual cryptography (EVC) are printed on transparent sheets or fabricated with diffractive optical elements and metasurface, but these methods are expensive and disposable. To solve these problems, we proposed an optical image encryption scheme that combines EVC and NPE. In the encryption process, the secret image is decomposed into multiple shares that are digitally loaded on the SLM, and the ciphertexts are generated according to the ptychographic encoding scheme. The decryption is performed by superimposing the shares reconstructed from the ciphertexts. We present optical experiments to demonstrate the feasibility and effectiveness of the proposed method.
High-conductivity flexible Ag films formed by low-temperature and short-time sintering of PVP-modified silver oxalate composite ink
Authors: Fan PeiYuan , Zhang WenHua , Yu Xianglei , Gan GuoYou
Published: January 2022

Attaining low-temperature sintering and high electrical conductivity is vital in the field of flexible electronics. Inks with silver oxalate as the precursor have recently received significant attention in this field; however, the high sintering temperature and long sintering time limit commercial applicability. High sintering temperature can shorten the sintering time but lead to porous and uneven film morphology; thus, reducing the conductivity. On the other hand, low sintering temperature prolongs the sintering time; thus, reducing the production efficiency. To solve the abovementioned problems, a silver composite conductive ink modified by polyvinylpyrrolidone (PVP) was prepared in this study. The ink used silver oxalate as the precursor, methanol and acetone as the solvent, and 1, 2-diaminopropane as the complexing agent, and could reduce the sintering temperature and time to 160 °C and 20 min, respectively. After sintering, the silver film showed good electrical conductivity, and low resistivity (4.56 μΩ·cm). Furthermore, the impact of sintering temperature on the surface morphology and electrical conductivity were also studied, and the results showed that PVP had a positive influence on the nucleation of silver and the microstructure of the sintered silver film.
The effect of lubricant viscosity on the performance of full ceramic ball bearings
Authors: Sun Jian , Yang Jiaxing , Yao Jinmei , Tian Junxing , Xia Zhongxian , Yan Haipeng , Gao Longfei , Li Songhua , Bao Zhigang
Published: January 2022

As a new high-end bearing product, full ceramic ball bearings are favoured in a variety. However, there have been few studies on the lubrication of full ceramic ball bearings. The purpose of this study is to reveal the relationship between the vibration and temperature rise of full ceramic angular contact ball bearings and the lubricant viscosity, and to improve the service life of the bearings. In this study, the effects of lubricant viscosity on the vibration and temperature rise of silicon nitride full ceramic angular contact ball bearings under different axial loads and rotation speeds were tested. Herein, a mathematical model of oil lubrication suitable for full ceramic ball bearings is established and the relationship between the lubricant viscosity, lubricant film thickness, outer ring vibration and temperature rise of the bearing is analyzed. It was found that the vibration and temperature rise first decrease and then increase with the increase of lubricant viscosity. In this range, there is an optimal viscosity value to minimize the vibration and temperature rise of the full ceramic angular contact ball bearing. The contact surface wear of the full ceramic angular contact ball bearing varies greatly under different lubricant viscosities. There is no obvious wear on the contact surface under optimal viscosity, and the service life of the bearing is greatly improved. These results can play an important role in revealing the lubricant mechanism of full ceramic ball bearings and improving their service life under optimal lubrication.
Fabrication and characterization of SiC-reinforced Al-4032 metal matrix composites
Authors: Saini Pardeep , Singh Pradeep K
Published: January 2022

Aluminium metal matrix composites (AMCs) have become quite popular for light weight, low cost, and good workability. The present work reports the impact of silicon carbide (SiC) reinforcement on the physical, microstructural, and mechanical characteristics of Al-4032/SiC composites with 4, 6, 8% of SiC (particle size 54μm) fabricated through bottom pouring stir casting set-up. Density and porosity measurements of the AMC samples have been performed using the rule of mixture. The microstructure of the AMC samples has been analyzed using optical microscope (OM), x-ray diffraction analysis (XRD), and scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). The mechanical properties, in terms of the ultimate tensile strength (UTS), elongation, micro-hardness, and impact toughness of the AMCs have also been measured according to American society for testing and materials (ASTM) standards. A maximum 1.52% increase in theoretical density, while a maximum 2.92% decrease in experimental density has been recorded for 8% reinforcement. The UTS, microhardness, and impact toughness of the AMC samples have been found to improve significantly owing to the addition of ceramic particles. The uniform distribution of SiC particles all over base Al-4032 matrix material has been noticed by SEM and OM for AMCs up to 6% reinforcement. The reinforcement particles tend to agglomerate beyond this composition.
Coordinate rings and birational charts
Authors: Fomin Sergey , Lusztig George
Published: January 2022

Let

G
G

be a semisimple simply connected complex algebraic group. Let

U
U

be the unipotent radical of a Borel subgroup in 

G
G

. We describe the coordinate rings of

U
U

(resp.,

G

/

U

G/U

,

G
G

) in terms of two (resp., four, eight) birational charts introduced by Lusztig [Total positivity in reductive groups, Birkhäuser Boston, Boston, MA, 1994; Bull. Inst. Math. Sin. (N.S.) 14 (2019), pp. 403–459] in connection with the study of total positivity.
Multiscale scattering in nonlinear Kerr-type media
Authors: Maier Roland , Verfürth Barbara
Published: January 2022

We propose a multiscale approach for a nonlinear Helmholtz problem with possible oscillations in the Kerr coefficient, the refractive index, and the diffusion coefficient. The method does not rely on structural assumptions on the coefficients and combines the multiscale technique known as Localized Orthogonal Decomposition with an adaptive iterative approximation of the nonlinearity. We rigorously analyze the method in terms of well-posedness and convergence properties based on suitable assumptions on the initial data and the discretization parameters. Numerical examples illustrate the theoretical error estimates and underline the practicability of the approach.
A posteriori error analysis for approximations of time-fractional subdiffusion problems
Authors: Banjai Lehel , Makridakis Charalambos
Published: January 2022

In this paper we consider a sub-diffusion problem where the fractional time derivative is approximated either by the L1 scheme or by Convolution Quadrature. We propose new interpretations of the numerical schemes which lead to a posteriori error estimates. Our approach is based on appropriate pointwise representations of the numerical schemes as perturbed evolution equations and on stability estimates for the evolution equation. A posteriori error estimates in

L
2

(
H
)

L^2(H)

and

L
∞

(
H
)

L^\infty (H)

norms of optimal order are derived. Extensive numerical experiments indicate the reliability and the optimality of the estimators for the schemes considered, as well as their efficiency as error indicators driving adaptive mesh selection locating singularities of the problem.
Even solutions of some mean field equations at non-critical parameters on a flat torus
Authors: Kuo Ting-Jung , Lin Chang-Shou
Published: January 2022

In this paper, we consider the mean field equation
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Delta u plus e Superscript u Baseline equals sigma-summation Underscript i equals 0 Overscript 3 Endscripts 4 pi n Subscript i Baseline delta Subscript StartFraction omega Sub Subscript i Subscript Over 2 EndFraction Baseline in upper E Subscript tau Baseline comma">

Δ
u
+

e

u

=

∑

i
=
0

3

4
π

n

i

δ

ω

i

2

 in 

E

τ

,

\begin{equation*} \Delta u+e^{u}=\sum _{i=0}^{3}4\pi n_{i}\delta _{\frac {\omega _{i}}{2}}\text { in }E_{\tau }, \end{equation*}

where

n

i

∈

Z

≥
0

,

n_{i}\in \mathbb {Z}_{\geq 0},

E

τ

E_{\tau }

is the flat torus with periods

ω

1

=
1

\omega _{1}=1

,

ω

2

=
τ

\omega _{2}=\tau

and

Im
⁡
τ
>
0

\operatorname {Im}\tau >0

. Assuming

N
=

∑

i
=
0

3

n

i

N=\sum _{i=0}^{3}n_{i}

is odd, a non-critical case for the above PDE, we prove:

(i) If among

{

n

i

|

i
=
0
,
1
,
2
,
3
}

\{n_{i}|i=0,1,2,3\}

there is only one odd integer, then there is always an even solution. Furthermore, if

n

0

n_{0}

=
=

0
0

and

n

3

n_{3}

is odd, then up to

S

L

2

(

Z

)

SL_{2}(\mathbb {Z})

action, except for finitely many

E

τ

E_{\tau }

, there are exactly

n

3

+
1

2

\frac {n_{3}+1}{2}

even solutions.

(ii) If there are exactly three odd integers in

{

n

i

|

i
=
0
,
1
,
2
,
3
}

\{n_{i}|i=0,1,2,3\}

, then the equation has no even solutions for any flat torus

E

τ

E_{\tau }

.

Our second result might suggest the symmetric solution of the above mean field equation does not hold in general.
The transcriptional response to oxidative stress is independent of stress-granule formation
Authors: Singh Amanjot , Kandi Arvind Reddy , Jayaprakashappa Deepa , Thuery Guillaume , Purohit Devam J. , Huelsmeier Joern , Singh Rashi , Pothapragada Sai Shruti , Ramaswami Mani , Bakthavachalu Baskar
Published: January 2022

Acute cell stress induces several genes involved in cellular protein quality control and these are even further up-regulated during recovery from stress. We show that stress granule assembly is not part of a signaling network that regulates transcription during oxidative stress and recovery from it.
scNAME: neighborhood contrastive clustering with ancillary mask estimation for scRNA-seq data
Authors: Wan Hui , Chen Liang , Deng Minghua
Published: January 2022

Motivation

The rapid development of single-cell RNA sequencing (scRNA-seq) makes it possible to study the heterogeneity of individual cell characteristics. Cell clustering is a vital procedure in scRNA-seq analysis, providing insight into complex biological phenomena. However, the noisy, high-dimensional and large-scale nature of scRNA-seq data introduces challenges in clustering analysis. Up to now, many deep learning-based methods have emerged to learn underlying feature representations while clustering. However, these methods are inefficient when it comes to rare cell type identification and barely able to fully utilize gene dependencies or cell similarity integrally. As a result, they cannot detect a clear cell type structure which is required for clustering accuracy as well as downstream analysis.

Results

Here, we propose a novel scRNA-seq clustering algorithm called scNAME which incorporates a mask estimation task for gene pertinence mining and a neighborhood contrastive learning framework for cell intrinsic structure exploitation. The learned pattern through mask estimation helps reveal uncorrupted data structure and denoise the original single-cell data. In addition, the randomly created augmented data introduced in contrastive learning not only helps improve robustness of clustering, but also increases sample size in each cluster for better data capacity. Beyond this, we also introduce a neighborhood contrastive paradigm with an offline memory bank, global in scope, which can inspire discriminative feature representation and achieve intra-cluster compactness, yet inter-cluster separation. The combination of mask estimation task, neighborhood contrastive learning and global memory bank designed in scNAME is conductive to rare cell type detection. The experimental results of both simulations and real data confirm that our method is accurate, robust and scalable. We also implement biological analysis, including marker gene identification, gene ontology and pathway enrichment analysis, to validate the biological significance of our method. To the best of our knowledge, we are among the first to introduce a gene relationship exploration strategy, as well as a global cellular similarity repository, in the single-cell field.

Availability and implementation

An implementation of scNAME is available from https://github.com/aster-ww/scNAME.

Supplementary information

Supplementary data are available at Bioinformatics online.
Life expectancy and likelihood of surgery in multiple endocrine neoplasia type 1: AFCE and GTE cohort study
Authors: Gaujoux Sébastien , Martin Guillaume L , Mirallié Eric , Regenet Nicolas , Le Bras Maëlle , Pattou François , Carnaille Bruno , Cardot-Bauters Catherine , Groussin Lionel , Faron Matthieu , Chanson Philippe , Najah Haythem , Tabarin Antoine , Sauvanet Alain , Ruszniewski Philippe , Lifante Jean Christophe , Walter Thomas , Carrère Nicolas , Caron Philippe , Deguelte Sophie , Delemer Brigitte , Binquet Christine , Jannot Anne Sophie , Goudet Pierre
Published: January 2022

Background

The overall natural history, risk of death and surgical burden of patients with multiple endocrine neoplasia type 1 (MEN1) is not well known.

Methods

Patients with MEN1 from a nationwide cohort were included. The survival of patients with MEN1 was compared with that of the general population using simulated controls. The cumulative probabilities of MEN1-specific operations and postoperative mortality were assessed, and surgical sequences were analysed using sunburst charts and Venn diagrams.

Results

A total of 1386 patients with MEN1 were included. Life expectancy was significantly reduced in patients with MEN1 compared with simulated controls from the general population, with a lifetime difference of 15 years. Mutations affecting the JunD interaction domain had a significant negative impact on survival. Survival for patients with MEN1 compared with the general population improved over time. The probability of experiencing at least one specific MEN1 operation was above 95 per cent after 75 years, and most patients had surgery at least twice during their lifetime. Time to a 50 per cent risk of MEN1 surgery was 30.5 years for patients born after 1960, compared with 47.9 years for those born before 1960. Sex and mutations affecting the JunD interacting domain had no impact on time to first surgery. There was considerable heterogeneity in surgical sequences, with no specific clinical pathway.

Conclusion

Life expectancy was significantly lower among patients with MEN1 compared with the general population, and further decreased in patients with mutations affecting the JunD interacting domain. Almost all patients underwent at least one MEN1-specific operation during their lifetime, but there was no standardized sequence of surgery.
Individual slow wave events give rise to macroscopic fMRI signatures and drive the strength of the BOLD signal in human resting-state EEG-fMRI recordings
Authors: Ilhan-Bayrakcı Merve , Cabral-Calderin Yuranny , Bergmann Til Ole , Tüscher Oliver , Stroh Albrecht
Published: January 2022

The slow wave state is a general state of quiescence interrupted by sudden bursts of activity or so-called slow wave events (SWEs). Recently, the relationship between SWEs and blood oxygen level–dependent (BOLD) functional magnetic resonance imaging (fMRI) signals was assessed in rodent models which revealed cortex-wide BOLD activation. However, it remains unclear which macroscopic signature corresponds to these specific neurophysiological events in the human brain. Therefore, we analyzed simultaneous electroencephalographic (EEG)-fMRI data during human non-REM sleep. SWEs individually detected in the EEG data were used as predictors in event-related fMRI analyses to examine the relationship between SWEs and fMRI signals. For all 10 subjects we identified significant changes in BOLD activity associated with SWEs covering substantial parts of the gray matter. As demonstrated in rodents, we observed a direct relation of a neurophysiological event to specific BOLD activation patterns. We found a correlation between the number of SWEs and the spatial extent of these BOLD activation patterns and discovered that the amplitude of the BOLD response strongly depends on the SWE amplitude. As altered SWE propagation has recently been found in neuropsychiatric diseases, it is critical to reveal the brain’s physiological slow wave state networks to potentially establish early imaging biomarkers for various diseases long before disease onset.