bluuebunny/crossref_metadata_2025 huggingface dataset:
High performance VLSI architecture for advanced QPSK modems
Authors:   State University of Telecommunications, Trenyova K. O.
Published: September 2023

The article is devoted to the topical issue of creating a high-performance VLSI architecture for advanced QPSK modems. The QPSK modulation scheme is used in VLSI architecture for many high-speed applications such as satellite communications. VLSI is a technology by which 10,000-1 million transistors can be manufactured on a single chip. Since there was a need for additional functions of electronic devices, the development of NVIS technology improved. The proposed architecture is modeled in XILINX software. This software product is specialized tools for programming programmable logic devices in hardware description languages. The main goal of the research is to create a high-performance QPSK module, thanks to which it supports satellite communication with high bandwidth and energy efficiency. A QPSK modulator is a binary (base 2) signal that produces four different sets of input combinations: 00, 01, 10, and 11. Therefore, with QPSK, binary input combinations are combined from two bits. In the proposed project, 8-PSK and 16-PSK modulation with the basics of QPSK modulation and demodulation system were analyzed and modeled to obtain the required output. VERILOG coding was used for program simulation. Verilog is a hardware description language (HDL) used to model electronic systems. Verilog can run on both Windows 7, 8 and Windows 10 operating systems. Errors are coded and checked using XILINX software. This project is implemented to create high performance in NVIS using QPSK, 8-PSK, 16-PSK systems used for satellite communication. Implementing this process in any other module is easy, but in NVIS it is a big challenge.
Zero trust architecture: the basics organization principles
Authors:   State University of Telecommunications, Prydybailo O. B.
Published: September 2023

Zero trust (ZT) is the term for an evolving set of cybersecurity paradigms that move defenses from static, network-based perimeters to focus on users, assets, and resources. A zero trust architecture (ZTA) uses zero trust principles to plan industrial and enterprise infrastructure and workflows. Zero trust assumes there is no implicit trust granted to assets or user accounts based solely on their physical or network location (i.e., local area networks versus the internet) or based on asset ownership (enterprise or personally owned). Authentication and authorization (both subject and device) are discrete functions performed before a session to an enterprise resource is established. Zero trust is a response to enterprise network trends that include remote users, bring your own device (BYOD), and cloudbased assets that are not located within an enterpriseowned network boundary. Zero trust focuses on protecting resources (assets, services, workflows, network accounts, etc.), not network segments, as the network location is no longer seen as the prime component to the security posture of the resource. This document contains an abstract definition of zero trust architecture (ZTA) and gives general deployment models and use cases where zero trust could improve an enterprise’s overall information technology security posture. This article describes zero trust for enterprise security architects. It is designed to help understand zero trust for civilian unclassified systems and provide a roadmap for the migration and deployment of zero trust security concepts in an enterprise environment. Starting with a clear understanding of the organization’s business and data can lead to a strong zero-trust approach for enterprise security architects.
Energy­efficient technologies in the Internet of Things (IoT)
Authors:   State University of Telecommunications, Sverdliuk B. І.
Published: September 2023

The internet of things (IoT) has a significant economic and environmental impact owing to the billions or trillions of interconnected devices that use various types of sensors to communicate through the internet. It is well recognized that each sensor requires a small amount of energy to function; but, with billions of sensors, energy consumption can be significant. Therefore, it is crucial to focus on developing energy-efficient IoT technology and sustainable solutions. The contribution of this article is to support the implementation of eco-friendly IoT solutions by presenting a thorough examination of energy-efficient practices and strategies for IoT to assist in the advancement of sustainable and energy-efficient IoT technologies in the future. Four framework principles for achieving this are discussed, including (i) energy-efficient machine-to-machine (M2M) communications, (ii) energy-efficient and eco-sustainable wireless sensor networks (WSN), energy-efficient radio-frequency identification (RFID), and energy-efficient microcontroller units and integrated circuits (IC). This review aims to contribute to the next-generation implementation of eco-sustainable and energy-efficient IoT technologies. The internet of things (IoT) is a revolutionary technology driving telecommunications advancements and improving people’s quality of life worldwide. The IoT also has the potential to boost the global economy significantly. It is anticipated that the global economic impact of the IoT will be between USD 2.7 trillion and 6.2 trillion by 2025 due to IoT devices that are a critical component of emerging applications and play a central role in the widespread adoption of machine type communications. According to experts, the IoT has the potential to revolutionize different smart zones including modern healthcare applications, smart homes and smart cities
Development and research of modern methods of wireless information transmission
Authors:   State University of Telecommunications, Parkhomenko V. L.
Published: September 2023

The importance and relevance of studying the topic of the development of wireless technical means of transmission is obvious even with a superficial survey of the prevalence of transponders in modern devices and concepts, such as, for example, the concept of a «smart» house. Despite the fact that the development of transmission technologies reaches a significant level, the loads on information transmission channels are constantly expanding, so the development of existing and research into new ways of transmitting radio waves are relevant and noticeable. The rapid development of information communication technologies and the increasing need for fast and reliable data exchange have led to the urgency of researching modern means of wireless information transmission. Wireless networks are necessary to provide communication between free devices and remote users. Research in this area allows to expand knowledge about modern wireless technologies, their principle of operation, advantages and disadvantages, as well as the possibilities of application in various fields, such as telecommunications, medicine, transport and others. The study will also help identify some security and privacy issues in wireless networks and develop effective measures to protect them. This is especially important in the context of a decrease in the number of cyber attacks and crimes related to information system security breaches. It is necessary to conduct research on such technologies for their further development. Thus, the research of modern means of wireless information transmission is an important and topical topic that plays an important role in the development of information communication technologies and information protection. The mentioned facts and circumstances indicate the importance of conducting research and the possible positive result of the impact on widespread technical devices.
Methodological approach to assessing the influence of ionizing radiation on the efficiency of functioning of free­space optical communication
Authors:   State University of Telecommunications, Vyshnivskyy V. V.
Published: September 2023

The methodological approach to the assessment of the influence of ionizing radiation on the efficiency of functioning of free-space optical communication, taking into account technogenically loaded territories of Ukraine, is considered. It is indicated that the efficiency of functioning of free-space optical communication (FSO) should be methodologically examined through the influence of external factors using an integrated approach taking into account the concept of uranium heritage in Ukraine and Europe. It is proved that the protection of FSO transceivers from gamma radiation will be determined by the attenuating ability of their design elements and the direction of the radiant flux vector. The conclusions that it is possible to reduce the level of ionizing radiation impact on the FSO receiver by selecting a receiver with the required value of integral sensitivity, as well as by reducing the bandwidth, are confirmed. The dependence of the average energy of gamma radiation on the angle of incidence at the observation point is established. It is pointed out that the influence of ionizing radiation leads to a decrease in the signal-to-noise ratio and effective sensitivity of the receiver. In some cases, ionizing radiation can cause communication interruptions due to receiver saturation. In addition to the useful signal, the receiver lens also collects some unwanted background radiation, which may consist of direct sunlight, reflected sunlight or scattered sunlight from hydrometeors or other objects. Their effect can be reduced by using a narrow spectral bandwidth and spatial filtering before photodetection. However, minor background noise can enter the spatial and frequency ranges of the detector, which can limit system performance by causing a variable offset in the converted electrical signal.
Comparative analysis of methods for increasing the speed of searching аnd recording information in databases
Authors:   National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Kornaga Ya. I.
Published: September 2023

The work examines the methods of increasing the speed of writing and searching information, namely the method of combining indexes and the method of temporary tables. It is noted that today it is necessary to create new methods that can increase the efficiency of records and search for information in databases, which would allow speeding up the mentioned processes and more efficiently using DBMS resources. The basis of the first method in the work is a special index that combines the use of fields with the same type and value from different tables. The basis of the second method is the use of a temporary table in which data is written and in which there are no indexes. It is noted that the method of combining indexes is effectively used when the database uses fields with the same type and value in different tables. After finishing work on this table, they are rewritten in the main one, and the indexes are already being rearranged there. A description of the algorithms describing the operation of these methods was developed, and an analytical evaluation was carried out to confirm the effectiveness of the methods. For conducting experiments, a special software package was developed for researching the effectiveness of searching and recording information in the database, which can be adapted to different operating systems (Linux, Ubuntu, etc.). Its use made it possible to fully perform experiments and confirm analytical data with experimental ones. It is highlighted that the search based on the method of combined indexes is advisable to use for those tables that are most often searched and the fields in which they are most often compared with each other. It is emphasized that the choice of a certain method of recording and searching for data depends on several parameters of the database construction, namely: the number of tables and records in them, the number of references to the corresponding table, the number of constructed indexes on the corresponding table, and the types of data in the corresponding fields of the database.
Adaptation of the mechanistic approach to the analysis of the cryptocurrency market
Authors:   State University of Telecommunications, Tsapro I. V.
Published: September 2023

The cryptocurrency market is rapidly developing, leading to increased research and development of new investment and trading strategies. Technical analysis is one of the methods of analysis in asset markets. It is based on using patterns and repetitions that correspond to certain behavior of an asset in the past to predict the behavior of the asset in the future. Therefore, analyzing digital currencies based on historical data is an important method for predicting price changes. The article highlights the use of a mechanistic approach to generalized technical analysis in the cryptocurrency market, which is based on physical principles and takes into account not only the price, but also the volume of transactions as a time-dependent generalized "mass". Such an interaction can be represented as a classical force (Newtonian mechanics) acting on an object (asset, index). However, given the high volatility and manipulability of digital assets, it is necessary to adapt the mechanistic approach to the considered market conditions. The article presents a generalized momentum formula and a momentum indicator formula for describing asset price changes as a complex effect between price and volume. Also, moving averages can be used for a generalized momentum indicator, but they often do not keep up with the price movement in the cryptocurrency market. Therefore, solving this problem, the application of the exponential moving average instead of the usual moving average, which reacts to price changes faster, is considered. The effectiveness of the adapted mechanistic approach for use in the cryptocurrency market, reducing the number of unprofitable deals and increasing the average profit, has also been confirmed. Applying the approach to the analysis of the cryptocurrency market has shown promising results, given that the analysis technique has previously proven successful in the stock markets.
Warehouse system based on IoT
Authors:   National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Garagan O. M.
Published: September 2023

This paper considers the option of improving the automation of a warehouse by introducing the Internet of Things. The system was designed taking into account the results of the analysis of the subject area research and the analysis of control options already available on the market, making it possible to identify key points for implementation in our control system. This made it possible to create a prototype system based on IoT sensors, which allows for efficient data collection and transmission in the proposed architecture. The created software can be used by companies and enterprises engaged in storage and logistics and individual entrepreneurs who want to automate warehouse processes.
George Tyrrell as a representative of the modernist movement of the Catholic Church
Authors: Захаров П. П. свящ.
Published: September 2023

В статье раскрывается эволюция взглядов известного английского модерниста католической церкви Джорджа Тиррелла. Исследование его произведений и трудов других католических богословов через призму его биографии показывает, как, будучи католическим священником, членом ордена иезуитов и преподавателем семинарии, увлеченность модернистскими идеями и желанием реформ привели его к полному разрыву с католической церковью. Будучи последовательным приверженцем неосхоластики в первой половине своей жизни, к её концу он пришел к публичному осуждению римского Папы и отрицанию необходимости института самой церкви, что не могло не вызвать жёсткого ответа со стороны официальной иерархии. Анализируется вклад Тиррелла в движение католического модернизма, которое в итоге привело ко II Ватиканскому собору.

The article covers the evolution of George Tyrrell's concepts, who was a famous English modernist of the Catholic Church. The investigation of his works and those of other Catholic theologians through the lens of his biography clearly demonstrates how his devotion to the ideas of modernism and his fervent desire to reform the Catholic Church led him to excommunication, despite him being a Catholic priest, a member of the Jesuit order, and a seminary teacher. Being a persistent supporter of neo-Scholasticism in his early life, later George Tyrrell began to publicly rebuke the Pope and even deny the necessity of the Catholic Church as an institution, which, in turn, could only have caused a harsh reply from its side. The article also analyzes Tyrrell's contribution into Catholic modernism, which eventually resulted in the Vatican II.
Creation and activity of parish councils in 1917–1918. (on the materials of the Tula diocese)
Authors: Резухин П. С. свящ. Резухин П. С. свящ.
Published: September 2023

В статье рассматривается этап демократизации церковной жизни Тульской епархии в условиях 1917–1918 гг., период крайне сложного процесса в истории Церкви — революционного брожения в приходах, ставшего следствием Февральской революции в России. На основе анализа доступных архивных документов автор воспроизводит картину «приходской революции», когда создавались приходские советы, бравшие в свои руки распоряжение церковной собственностью, решение налоговых вопросов, а также избрание членов причтов. Под влиянием революционных событий благочинные и епархия рассматривались в качестве бесполезных инстанций, обирающих население. В статье делается вывод, что в большинстве случаев «приходская революция» 1917 г. привела к формированию нового утилитарного отношения к Церкви в «низах», смыслом которого стал отказ от содержания церковной организации. Идея выборности органов епархиального управления, привлекавшая духовенство, радеющее за церковное обновление в предреволюционный период, болезненно ударила по положению самих клириков; стала началом разрушения церковной организации.

The article examines the stage of democratization of church life in the Tula diocese in the conditions of 1917–1918, the period of an extremely complex process in the history of the Church-revolutionary ferment in the parishes, which became a consequence of the February Revolution in Russia. Based on the analysis of available archival documents, the author reproduces a picture of the «parish revolution», when parish councils were created, taking control of church property, resolving tax issues, and also electing members of clergy. Under the influence of the revolutionary events, the deans and the diocese were viewed as useless institutions, robbing the population. The article concludes that in most cases the «parochial revolution» of 1917 led to the formation of a new utilitarian attitude towards the Church in the «lower classes», the meaning of which was the rejection of the content of the church organization. The idea of elective bodies of diocesan administration, which attracted the clergy, who were working for church renewal in the pre-revolutionary period, painfully hit the position of the clergy themselves; was the beginning of the destruction of the church organization.
Implementation of repressive measures against the clergy in the territory of Chuvashia in the 1920s–1930s.
Authors: Коршунов  К. О. иер. Коршунов  К. О. иер.
Published: September 2023

В данной статье рассматривается реализация репрессивной политики советской власти в 20–30 гг. прошлого века. События данного периода являются одними из самых трагичных в истории Церкви, и в наше время продолжается активное изучение архивных материалов событий тех трагичных лет. В статье изучены законодательные акты центральных и местных органов советской власти, направленные на ухудшение социального положения священнослужителей и приведены примеры по архивным данным. Большевистская власть использовала весь возможный спектр репрессивного давления на Православную Церковь: политические, экономические средства и даже физическое уничтожение, пыталась расколоть внутреннее единство Церкви путём создания и активной поддержки обновленческого движения. Учитывая этнокультурные особенности региона, законодательные акты, печатные агитационные материалы издавались на русском и чувашском языках. Гонения священнослужителей на территории Чувашии имели как общие черты, так и свои особенности; для нас, живущих в относительно спокойное время, актуальность представляет не только научный подход к событиям, но и изучение жизни священнослужителей, живших в периоды государственного террора и сохранивших самое важное для каждого христианина — веру в Бога.

This article examines the implementation of the repressive policy of the Soviet government in the 20–30 years of the last century. The events of this period are among the most tragic in the history of the Church, and in our time the active study of archival materials of the events of those tragic years continues. The article examines the legislative acts of the central and local Soviet authorities aimed at worsening the social status of the clergy and provides examples from archival data. The Bolshevik government used all possible range of repressive pressure on the Orthodox Church: political, economic and even physical destruction, tried to split the internal unity of the Church by creating and actively supporting the Renovationist movement. Taking into account the ethnocultural peculiarities of the region, legislative acts, printed propaganda materials were published in Russian and Chuvash. The persecution of the clergy on the territory of Chuvashia had both common features and their own peculiarities. For us who live in a relatively quiet time, the relevance is not only a scientific approach to events, but also the study of the lives of the clergy who lived during periods of state terror and preserved the most important thing for every Christian — faith in God.
A Study of the Economic Growth Quality in the Eastern Regions of Russia and the Northeastern Regions of China
Authors: Zabelina Irina
Published: September 2023

The article presents an assessment result of the economic growth quality in Eastern regions of Russia and the Northeastern regions of China, performed using the eco-intensity indicator and the colors of growth framework. It is shown that during the period from 2011 to 2021, the level of some types of negative environmental impact decreased in both countries. A comparative analysis of eco-intensity indicates that in 2021, Russia surpassed China in terms of emissions of sulfur dioxide and nitrogen oxides per unit of economic result. Positive trends were noted for these pollutants in China and its Northeastern regions: eco-intensity decreased significantly during the analyzed period. The study of trends in environmental and economic development using the colors of growth system showed that the entire trajectory of development of China and its regions in terms of emissions of sulfur dioxide and nitrogen oxides is in the most prosperous zone (the "green" growth zone). At the same time, some Eastern regions of Russia demonstrate negative dynamics: in some years, "black" growth and/or degrowth were revealed. Calculations have shown that in almost all regions of the East of the Russian Federation from 2011 to 2021, the eco-intensity of waste generation increased; the development trajectories for this type of ecological pressure were mainly in the "black" zones. The results obtained in this study allow us to analyze the ecological and economic trends in the development of regional and national economies and can be used in the process of developing strategic documents, including in the context of cross-border cooperation.
Prospects for Russian gas in China
Authors: Kondratov Dmitriy
Published: September 2023

The article presents an analysis of the current state and forecasts for the long-term development of the Chinese natural gas market, as well as the prospects for increasing Russian supplies of fossil fuels to this market.
It is expected that by the end of 2030 China can catch up and overtake Europe in terms of gas consumption. By 2030, the total demand for gas in China will be 390-560 billion cubic meters, which is almost 1.5 times higher than in 2022.
During the period of economic slowdown, the imbalance of supply and demand in the global hydrocarbon market leads to its destabilization. In order to predict such situations in advance, specialists from international and Russian organizations (International Energy Agency, BP plc, Energy Research Institute of the Russian Academy of Sciences, Institute of Energy Economics of Japan) and consulting companies (IHS Markit) periodically prepare papers on the evolution of world energy markets and the consequences for major countries. gas consumers. Almost all studies are not yet ready to name the period of peak demand for gas in China in the foreseeable future, which gives grounds to name the 21st century of gas transformation.
In this article, a study was made of the Chinese gas market and an analysis of the factors of the long-term dynamics of demand for this energy resource.
The author also made an attempt to assess the expansion of our country's participation in the Chinese gas market, and prepared interim recommendations on using the potential for developing energy cooperation between China and Russia.
At the same time, the northeastern provinces of China, located near the Russian border, after the launch of the Power of Siberia gas pipeline, will be saturated with Russian gas. At the same time, the insufficient development of gas infrastructure — pipeline capacities, gas storage facilities, distribution networks — in China will not allow increasing exports when Russia builds additional capacities. To an even greater extent, this applies to the Power of Siberia-2 gas pipeline project.
 
The most promising way to increase Russian gas exports to China is the organization of Russian LNG supplies to the coastal regions of China, where a steady growth in gas demand is predicted.
Numerical Study of Different Tools in High-Speed MQL Cutting of Aluminum Alloys
Authors: Xu Jinyang , Shen Jiaxin , Li Linfeng
Published: September 2023

Aluminum alloys have been extensively used in aerospace, machinery, transportation, and other industries due to their superior strength, relatively low weight, and outstanding thermal conductivity. High-speed cutting (HSC) and minimum quantity lubrication (MQL) techniques have been widely applied for the machining of aluminum alloys. This paper investigates numerically the influences of various geometrical tools on the cutting behaviors, in particular, the cutting forces/temperature of aluminum alloys. The effects of the rake angle and the friction coefficient are examined by simulations based on the orthogonal cutting mode. The findings of the numerical analysis may guide the design of cutting tools in high-speed MQL cutting for aluminum alloys.
Broadband Absorber Using Double-Layer Frequency Selective Surface Loaded with Resistors
Authors: Xie Junjie
Published: September 2023

A broadband absorber using a double-layer frequency selective surface (FSS) loaded with resistors is proposed in this paper. Absorptivity is used to obviously characterize the performance of the absorber. Simulation results show that this kind of absorber can achieve Absorptivity of over 90% in the frequency range between 6.98 and 21.12 GHz (fractional bandwidth of 100.64%). Moreover, the structure has a thickness of 4 mm. The influence of the parameters of the proposed absorber on the absorption is then presented and analyzed.
Prediction of Remaining Life of Structure Based on Phase-Field Method
Authors: Xie Guizhong , Jia Hangqi , Wang Liangwen , Du Wenliao , Dong Yunqiao , Zhong Yudong , Zhao Chongmao , Fu Beibei , Xu Shuaiqiang
Published: September 2023

In this work, a new approach for forecasting the remaining useful lifespan (RUL) of mechanical structure is described, which combines phase-field method (PFM) technology and the neural network (NN) technology. Firstly, the brittle fracture damage model is established according to the PFM. And the sample data, which are strain value and lifespan value at the observation locations of the damage model, are obtained by numerical simulation. Then, the obtained sample set is input into the NN as a training sample. And a mathematical model, which can forecast the structure’s RUL, is obtained by training. Finally, we assess the rationality of the proposed standpoint by means of a numerical simulation of a cracked plate. It is demonstrated that the presented approach for forecasting the remaining useful lifespan of the mechanical structure, which combines the PFM and NN technology, has a high performance.
Analysis of Variation in the Operating Life for Rolling Bearings
Authors: Meng Fannian , Wang Liujie , Gong Xiaoyun , Du Wenliao
Published: September 2023

The eigensequence probability density function is calculated based on the maximum entropy principles. The confidence interval of the vibration signal is calculated by Poisson’s principle. and a small number of bearing vibration acceleration signals are selected to obtain the number falling outside the confidence interval of the intrinsic sequence, and the variation frequency is calculated. Tasking the accelerated experimental data of XJTU-SY rolling bearing as an example, the analysis is carried out. It is concluded that there is a non-linear relationship between the bearing life and its variation probability, which can be generally divided into initial running-in stage, stable running-in wear stage, and severe wear stage. Each stage has its variation frequency range, from which the relationship between the bearing life and the variation frequency can be obtained, making a useful supplement to the bearing life analysis in the case of less data.
Human Posture Recognition Based on Isolation Forest Algorithm
Authors: Ge Hao , Jin Lizuo
Published: September 2023

With the rapid development of semiconductor technology and mobile communication networks, inertial sensors have higher performance, and correspondingly, the demand for human behavior recognition is increasing. At this stage, the mainstream research methods mainly analyze images in video streams. Although they can achieve good recognition results, due to the high requirements for camera location, environmental conditions, and privacy considerations, it is difficult to popularize behavior recognition methods for videos. Therefore, this article conducts research on human behavior recognition based on wearable sensor data, The innovative introduction of the isolation forest algorithm for prior processing of data can quickly detect anomalies in the behavior process, and also reduce data anomalies caused by the impact of sensor performance. Finally, the Convolutional Neural Networks is used for classification to obtain the final recognition results. The system has been tested on the MHEALTH datasets, and the recognition rate has reached 99.01%, achieving good classification results.
Radial Envelope Forming Law of Thin Wall Cylinder with Vertical Reinforcements
Authors: Min Yanlei , Zhuang Wuhao , Deng Zushen
Published: September 2023

In this paper, the law of radial envelope forming (REF) of thin wall cylinder with vertical reinforcements is studied by finite element numerical simulation. First, a finite element model for REF of thin wall cylinder with vertical reinforcements is established by using Deform-3D software. Then, the evolution and distribution of strain and metal flow velocity during REF of thin wall cylinder with vertical reinforcements are analyzed, and the growth law of vertical reinforcement during this REF is analyzed in detail. The results show that radial compression strain, circumferential tensile strain and axial tensile strain occur in the web. Radial tensile strain, circumferential compressive strain and axial tensile strain occur in the vertical reinforcements. The metal flows mainly in radial direction and circumferential direction during REF of thin wall cylinder with vertical reinforcements. The vertical reinforcements show nonlinear growth, and the middle part of the vertical reinforcement is higher than both ends of the vertical reinforcement.
Experimental Analysis of Interlayer Properties of Resin Matrix Based Composites
Authors: Bai Ruixiang , Li Xuwei , Liu Chen , Lei Zhenkun , Li Qian
Published: September 2023

The delamination failure is a common failure mode of high-performance carbon fiber reinforced resin composites during service. Aiming at understanding the mode I delamination behavior of T800/EH104 thermoset composites and T800/PC thermoplastic composites by DCB experiments method. The results show that the mode I fracture toughness of thermoplastic composites is greater than that of thermoset composites. During the crack propagation process, the “Jump” phenomenon of the load-displacement response curve of the specimen is obvious, and a serious unstable crack propagation phenomenon occurs.
Preparation of Fe3O4@UiO-66 and Application in Wastewater Purification: Highly Efficient Removal of Rhodamine B
Authors: Wang Lixia , Zhao Yufeng
Published: September 2023

Here, we are going to report a simple and low-cost to prepare the Fe3O4@UiO-66 by solvothermal method. X-ray diffractometer, scanning electron microscope, vibrating magnetometer, thermogravimetric analysis and Fourier infrared spectrophotometer were used to characterize Fe3O4@UiO-66. The Fe3O4@UiO-66 has uniform morphology, high crystallinity and high saturation magnetization Fe3O4@UiO-66 has high magnetic, provides efficient separation after removing Rhodamine B(RhB) possible suspension. The absorbance was measured by Ultraviolet visible spectrophotometer (UV) and the adsorption capacity was calculated. Adsorption capacity of Fe3O4@UiO-66 to RhB is 65.0 mg·g–1. Magnetic organic framework material will have broad application prospects as sewage treatment agents.
Review of Structural Health Monitoring in Bridges
Authors: Jiang Tinglong , Xiang Qi , Li Zeming
Published: September 2023

This paper aims to introduce structural health monitoring techniques. The health monitoring of the bridge structure is mainly divided into three stages. The data collected by the sensor can be extracted and its characteristics can be evaluated. For the detection of bridge structures, scholars at home and abroad have conducted a lot of research on data collection and sensor arrangement. In the health monitoring of bridge structures, the most critical link is to use sensors for data collection. This article focuses on two types of sensors, EME and FBG, which are used to measure strain and temperature, respectively. With the development of science and technology, more and more precision measurement techniques have been proposed. GNSS and Novelty detection are the main representatives of bridge safety monitoring.
The Study on Nonlinear Flutter of Long-Span Suspension Bridge
Authors: Liu Jieshan , Li Jinxiang , Liao Lican
Published: September 2023

Bridges are subject to large-amplitude vibrations, known as wind-induced vibrations, which can cause various problems in high winds. Flutter is the most serious vibration caused by self-excited force. In addition, long-span suspension bridges are flexible frames that are prone to large deformations. Many researchers have shown that flutter instability is affected by non-linear characteristics. In this paper, the equivalent linearisation method (ELM) is used to solve the flutter state of the nonlinear flutter system of a long-span suspension bridge with cubic torsional stiffness. By solving the equivalent linearisation equations, the wind speed of the critical flutter vibration was obtained, and the supercritical Hopf bifurcation and limit cycle oscillations (LCOs) were analysed.
Aeroelastic Model Design and Wind Tunnel Tests of Sail-Shaped Pylon in Free-Standing Stage
Authors: Li Jinxiang , Liu Jieshan , Liao Lican
Published: September 2023

As opposed to traditional symmetrical two-way pylons, the sail-shaped pylon presents an arched shape on the longitudinal bridge, and the flow field generated around it presents more obvious three-dimensional spatial effects when air flows. Therefore, the static and dynamic characteristics of sail-shaped pylons under the action of wind load are also different from those of conventional pylons. In order to study the wind resistance performance of the sail-shaped pylon in free-standing stage, taking the sail-shaped bare pylon of a certain cable-stayed bridge as the engineering background, an aeroelastic model satisfying the first 2 order frequency similarity ratio was designed by using the method of metal core beam plus wooden outer moldel. On this basis, the responses of vortex vibration and galloping in uniform flow field and turbulent flow field, as well as buffeting response in turbulent flow field were obtained by wind tunnel test of aeroelastic model, and the wind resistance performance of sail-shaped pylon of cable-stayed bridge was studied. The results show that when the wind direction is 0°, Vortex-induced vibration(VIV) may occur at the wind speed of 25.3 m/s ∼ 30.67 m/s, and the unilateral amplitude of VIV at the top of the tower is 79.5 mm. The wind tunnel tests of turbulence aeroelastic model show that, under the action of the design reference wind speed under construction condition, when the wind direction Angle is 80°, the root mean square of buffeting displacement in the transverse direction of the top of the pylon is the largest, which is 13 mm; when the wind direction Angle is 90°, the root mean square of buffeting displacement in the transverse direction is the largest, which is 14 mm, which does not affect the construction safety of the pylon.
Application of Demolition Technology of a Across-River Bridge in Shenzhen Municipal Project
Authors: Hu Cong , Xiao Yi , Yin Jun , Ouyang Xuanri , Xu Junpeng , Li Shumin , Yao Siqi
Published: September 2023

Take the demolition construction of a municipal road reconstruction project in Shenzhen city as an example, combined with the actual situation on site and safety, green construction and other related requirements, through a variety of program selection, the proposed use of island cofferdam directly broken down the overall program of demolition, the bridge demolition construction key technology safety, economy, in line with the design requirements and meet the relevant environmental protection construction requirements, demolition of construction waste is also reasonable disposal. The bridge demolition construction key technology is safe, economical, meets the design requirements and the relevant environmental protection construction requirements, the demolition construction waste is also disposed reasonably, and in the project has generated certain benefits, for the construction of cross-river highway bridge demolition provides engineering experience and reference significance.
Preparation and Performance of Geopolymer Pervious Concrete in Red Mud Slag Base
Authors: He Ning , Zhang Lijuan , Zhuang Xiaoya , Huang Hao , Yuan Zaide
Published: September 2023

Pervious paving is an essential element of sponge city construction. However, regular previous cement concrete only has a minimal filtering effect on surface runoff, and the preparation process produces significant amounts of carbon dioxide. Slag-based geopolymer pervious concrete has great mechanical qualities, being energy efficient and eco-friendly. Red mud is an alkaline residue released during the alumina refining process from bauxite mining, and there is no known way to treat it. This paper investigates the effects of red mud content, aggregate gradation, and alkali exciter content on the performance of red mud slag-based geopolymer pervious concrete (RMSGPC) through orthogonal experiments. It is discovered that the right red mud content can not only promote colloidal reaction but also remove heavy metal ions. Multi-graded aggregates can provide a better performance, and alkali exciter mainly has the greatest effect on mechanical properties.
Study on the Bond Performance Between Epoxy Asphalt and Cement
Authors: Gao Jiagui , Xie Bin , Chang Sheng , Sun Wuyun , Li Xianyan , Cai Jianwei
Published: September 2023

To evaluate the bond performance between epoxy asphalt and cement with temperature, loading rate, thermal aging, adhesive material, and its amount of oblique shear and pull-out tests were conducted using self-designed devices. The test results show that: (1) Interlayer bonding performance decreased greatly after soaking. The shear and pull-out strength of Styrene-Butadiene-Styrene (SBS) modified asphalt decrease by 75.1% and 30.3% respectively, while that of epoxy asphalt decreases by 47.4% and 30.7%; (2) Thermal aging is an important factor in interface performance degradation, the shearing and pulling strength decrease by 23.0% and 60.5% respectively; (3) As an adhesion material, epoxy asphalt is significantly better than that SBS-modified asphalt.
Theory and Numerical Analysis of “Non-Equivalent Cast-in-Site” Prefabricated Concrete Shear Wall
Authors: Zhang Zhongwei , Bai Guoliang , Luo Fajiang , Lu Huayong , Xu Guangxing , Ren Leping
Published: September 2023

“Equivalent cast-in-site” is the current consensus on the seismic performance of fabricated buildings from home and overseas, that is, through reliable construction and connection measures, the macroscopic seismic performance of fabricated buildings is not lower than that of cast-in-place reinforced concrete structure. However, the research shows that the failure mechanism, damage forms and seismic performance indexes of prefabricated structures are different from those of cast-in-site structures, and the theory of “non-equivalent cast-in-site” is more consistent with the characteristics of stress, force transmission and connection deterioration of prefabricated structures. In this paper, a macroscopic “non-equivalent” numerical calculation method is proposed for the fabricated shear wall connected by grouting sleeve. First, a numerical calculation model of shear wall without considering the influence of sleeve connection and one that can consider the influence of sleeve connection are established, respectively, and the difference in carrying capacity between the two models is compared and analyzed. Furthermore, the strain values of concrete, reinforcement and joints in the calculation model of “non-equivalent” shear wall under nonlinear push over analysis are obtained, and the material properties and failure mechanism are analyzed. It is hoped that the research results can be valuable for the calculation and analysis of assembled walls.
Study on the Damage Evolution of Concrete Under Acid Attack
Authors: Nie Liangxue , Zhao Zihan , Yin Yanqi , Bai Erlei , Cai Zuzhi , Zhang Tong
Published: September 2023

For the purpose of intensive study the damage evolution of concrete, to test and evaluate its durability under acid environment, a systematical and farther research on a series of performance attenuation of concrete specimens which have been immersion in acid solution was carried out by using of non-metal ultrasonic tester, Hydraulically driven test system and scanning electron microscope (SEM) test device, the research content mainly includes weight change, ultrasonic damage, static compressive strength etc. Results of the experimental indicated that: during corrosive period, the weight displays the law of increase firstly then decrease and finally increase again, the static compressive strength and ultrasonic velocity of corroded specimens both decreased significantly in different degrees, and present the trend of increase first then decrease; at the end of corrosion, the internal structure of concrete becomes very loose, and the size of internal cracks and pores become very large, accompanied by the serious degradation. Therefore, the acid environment has a significant corroding effect of weaken the mechanical properties on concrete, which greatly weakens its durability.
Numerical Simulation of Initial Crack Propagation of Steel-Concrete Composite Beams Based on XFEM
Authors: Wang Xie , Wang Da
Published: September 2023

The crack propagation of negative moment zone of steel-concrete composite beams with initial concrete cracks was numerically simulated, using the extended finite element method (XFEM), based on the finite element software ABAQUS. The correctness of the numerical simulation method was verified by comparing it with the existing model tests. It is found that the crack propagation and mechanical properties of negative moment zone of steel-concrete composite beams with initial concrete cracks are affected not only by the size and location of single cracks but also by the relationship between the locations of multiple cracks; among them, the location of transverse distribution of cracks and the location of longitudinal distribution of cracks are the main factors affecting the crack propagation of negative moment zone of steel-concrete composite beams with initial concrete cracks.
Deterioration Process and Microscopic Analysis of Hydraulic Concrete Under Salt Freeze Dry Wet Cycle
Authors: Liu Jun
Published: September 2023

To study the durability of hydraulic concrete under salt-freeze-dry-wet cycles, indoor accelerated tests of concrete under freeze-thaw-salt-encroachment-dry-wet conditions were designed to reveal the durability of hydraulic concrete under the coupling effect of multiple factors, using mass loss rate, the RDEM and pore structure as indicators. The results show that: the concrete deterioration process can be roughly divided into three stages, and the final damaged concrete appears to have dropped edges and exposed aggregates; the damage degree of concrete is related to its water-cement ratio and sulphate concentration, and the mass loss rate of concrete in the same period, the RDEM damage degree is compared by strength class: C25 > C35 > C45, and by sulphate concentration: 10% > 5% > 0% (clear water); sulphate crystallisation products were detected in the specimens using XRD physical phase analysis. It is demonstrated that the deterioration process of concrete under sulphate attack involves both physical and chemical attacks.
Effect of Double Fly Ash and Rice Husk Ash on Dry Shrinkage Mechanical Properties of Ceramsite Concrete
Authors: Ran Wenjie , Wang Liangpeng , Peng Chunping , Xie Lei
Published: September 2023

In this paper, the effects of fly ash and rice husk ash on the drying shrinkage of ceramsite concrete were studied by testing the drying shrinkage amount and the corresponding compressive strength of ceramsite concrete at different ages, and according to the corresponding mechanical properties, the correlation between the shrinkage strain and compressive strength of ceramsite concrete was further explored. The research shows that the drying shrinkage of ceramsite concrete can be effectively reduced by adding 30% fly ash and 15% rice husk ash, and with the increase of rice husk ash content, the compressive strength of concrete also increases gradually. Through fitting analysis, it is found that there is a good curve regression relationship between shrinkage strain and compressive strength of ceramsite concrete, and the regression equation is predicted. Finally, the optimal mixing ratio was determined through experiments, which ensured that the double mixing of fly ash and rice husk ash could reduce the drying shrinkage of concrete and improve the compressive strength of concrete.