bluuebunny/crossref_metadata_2025 huggingface dataset:
Edaravone-Loaded Sodium Alginate/Carboxymethyl Chitosan Composite Flim for the Healing of Chronic Wound
Authors: Li Jianxiao , Xu Chao , Sun Changkai , Guan Shui
Published: April 2023

High levels of reactive oxygen species (ROS) in the wound surface are one of the reasons why chronic wounds are difficult to heal. Using of free radical scavengers to reduce ROS levels and reduce the duration of toxic effects of ROS can accelerate the healing of chronic wounds. In this study, a novel edaravone (Ed)-loaded sodium alginate (SA)/carboxymethyl chitosan (CMCS) antioxidant composite film was prepared, and the physicochemical properties and biocompatibility were analyzed. The results indicated that the SA/CMCS/Ed films were hydrophilic, with excellent water absorption and water retention, and also exhibited adequate mechanical properties. The exploratory drug release investigation revealed that the increase in SA content plays a critical role in the Ed release process by improving the binding ability of the composite film to the drug, resulting in slow release. In addition, cell experiments confirmed that the SA/CMCS films with Ed content of 20% and 30% not only had no cytotoxicity, but also significantly promoted the cell viability of fibroblasts from oxidative stress injury induced by hydrogen peroxide. These preliminary results suggested that the Ed-loaded SA/CMCS composite film can be further used for the study of chronic wound dressings, which is expected to provide new ways for the treatment of diabetic foot ulcers, lower extremity venous ulcers and arterial ulcers.
Thermodynamic Analysis Modelling of In Situ Al-Ti-B Alloy Formed by Fluorine Salt Method
Authors: Wang Minghao , Zhang Guangzong , Guo Lili , Li Junwen , Li Gengyang , Guan Renguo
Published: April 2023

Al-Ti-B master alloy is currently the most widely used grain refiner in aluminum alloys. Reaction controlling plays an important role in changing alloy microstructure and improving the refining effect. In this paper, Al-Ti-B master alloy is prepared by the fluoride salt method, and the control of the in-situ generated phases is realized by establishing a thermodynamic analysis modelling. Results show that the reactant change caused by the difference of alloy system directly determines the reaction sequence, which in turn affects the type and quantity of phases. The combination of elemental Ti and B is affected by the reaction system. When KBF4 is firstly consumed, TiB2 and TiAl3 are produced. And when K2TiF6 is firstly consumed, only TiB2 and AlB2 are generated in the system. Thermal balance calculation results indicate that aluminothermic reaction has a contribution to the pool temperature, which facilitates to improve the kinetic conditions of the reduction reaction.
Machine Learning Model of Oilfield Productivity Prediction and Performance Evaluation
Authors: Song Laiming , Wang Chunqiu , Lu Chuan , Yang Shuo , Tan Chaodong , Zhang Xiongying
Published: April 2023

Accurate and efficient prediction of oilfield productivity is very important for the formulation of development and adjustment plans. Machine learning (ML) productivity prediction model can quickly obtain the productivity of oilfield development. In this paper, an oilfield development productivity prediction model based on five ML algorithms including multivariable linear regression (LR), extreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM), back propagation (BP) neural network and long short term memory (LSTM) neural network is established. Through the evaluation of model performance indicators (include the root mean square error (RMSE), the coefficient of determination (R2), the mean absolute error (MAE) and mean absolute percentage error (MAPE)), the best performance prediction model is selected. The research results show that the prediction results of LR model are greatly affected by the data of high productivity oil wells, XGBoost model are easily affected by fitting, and BP neural network model is far less effective than other models. Through comprehensive comparison of prediction results, LightGBM model has better stability and generalization performance. The difference between the prediction results of each model is mainly caused by the characteristics of the algorithm and the size of the data sets. At the same time, LSTM can predict the future oil well production based on the oil well time series observation data. The research results of this paper have guiding significance for the selection of productivity prediction model for oilfield development based on data-driven.
Study of Air Pressure on Arc Ion Plating on Epoxy Resin Matrix Composites at Meter Range Working Distance
Authors: Meng Chao , Ma Zhandong , Xue Hongming , Yue Shoujing , Gao Zhen , Liu Xing
Published: April 2023

The metal film was deposited on the surface of epoxy resin based composite by arc ion plating technology. The distribution of metal ions at the interface of matrix was simulated. The growth mode of metal ions on the composite surface was analyzed. The deposition rate, surface morphology and membrane base bonding strength were investigated. The results show that the transition layer of nm level will be formed on the surface of composite materials, and the larger the sputtering energy of metal ions, the deeper the distribution on the surface of composite materials. Nucleation occurs at the junction of fiber and resin matrix, and the fusion of nucleated particles grows along the fiber boundary with the increase of deposition time, and extends to the vertical fiber direction. Finally, the particles between fibers and the particles on the boundary gradually expand and merge into layered films. The working pressure decreased, the deposition rate of metal increased, the grain size decreased, the large particles on the surface of the metal coating decreased, and the bonding strength of the film base increased.
The Law Study of Arc Ion Plating on Cyanate Ester Composite Surface
Authors: Xue Hongming , Wang Fengchen , Meng Chao , Zhang Ping , Yue Shoujin
Published: April 2023

Silver film was deposited on cyanate ester composite by arc ion plating technology; the thickness of the coating, the surface resistance of the coating, the surface morphology and the membrane-based bonding strength were measured by surface profiler, four probe instrument, election microscope and electronic tension machine respectively. The influences of different process parameters on the deposition rate, electronic conductivity and feeding force of metal films were obtained by analyzing the test results. The results show that the target distance is the most important factor affecting the deposition rate of metal silver. Under the same working current, the lower working pressure, the higher deposition rate of metal silver on the surface of cyanate ester composite, the higher membrane-based bonding strength and the finer surface. The higher the working current, the higher the average deposition rate, the better the thickness and hardness of the metal coating. The uniformity of film was greatly improved by optimizing the parameters.
Causes of Ponding in Foundation Gallery of Fenhe Reservoir II Gravity Dam
Authors: Wang Runying , Xu Miao , Zhou Yonghong
Published: April 2023

The multi field coupling mechanism of seepage, stress and temperature coupling of concrete gravity dam is analyzed, and its coupling control equation is deduced. Based on the analysis of the temperature effect of cracked concrete dam, a three field coupling model of seepage, stress and temperature based on pore crack dual medium suitable for the characteristics of RCC gravity dam is established, and its implementation strategy in COMSOL Multiphysics is studied. The three-dimensional finite element model of the overflow dam of Fenhe Reservoir II is established, and the annual working behavior of the overflow dam section is simulated in COMSOL Multiphysics. The variation law of dam seepage characteristics under the coupling action of seepage, stress and temperature is obtained. It is considered that the ponding in the gallery mainly comes from the crack leakage, and the temperature and headwater elevation are the main factors affecting the crack leakage of the dam.
A Simple Analytical Approach for Stress Calculation of Solar Cells
Authors: Li Zhiqi
Published: April 2023

A simple analytical solution was proposed for stress evaluation of the solar cells. The present solution was then applied to the stress calculation of the cells in 1580mm×808mm PV module, the variation of the wind pressures and the shear storage modulus of the EVA were taken into account in calculation. The results from the present solution show in good agreement with those by FE.
Study on the Engineering Properties of Waste Soil-Based Flowable Fill
Authors: Liu Hao , Huang Zheng , Qi Wen , Shi Han , Yao Lijuan
Published: April 2023

Flowable fill is developed mainly for the difficult backfilling and compaction such as side trenches of foundation pits and retaining wall backfills. It can make use of waste soils. It has good flowability before curing, and thus can be compacted by its own weight. It also has high strength after curing. In this study, by using on-site waste soils as the raw material soil, 25 groups of flowable fill experiments were carried out. The relationship between flowability, strength and mix ratio of flowable fills was analyzed. The results show that the flowability of flowable fill increases with the increase of water-soil ratio and decreases with the increase of cement-soil ratio. It shows that the water-soil ratio is the main control index of its flowability. The strength of flowable fill increases with the increase of cement-soil ratio, and decreases with the increase of water-soil ratio. The water-cement ratio can be used as the main control index for the strength of the material within the tested range.
Rigid Spliced Box Girder Bridge under the Action of Foundation Settlement Difference Analysis of Mechanical Behavior of Splice Section
Authors: Xu Liang , Qiu Zhefeng , Li Yang , Dong Yidan , Zhou Xiaoyong
Published: April 2023

In a main line viaduct widening project, the old bridge is 35m+55m+35m three-span variable section prestressed concrete continuous box girder, which has the characteristics of large width, long span, variable section of beam body, large cantilever (4.05m), and transverse prestressed steel beams arranged on the bridge panel, etc. The old and new box girders adopt rigid joint scheme. Articles on rigid splicing box girder bridge in foundation settlement under the action of splicing mechanical properties to carry out the finite element analysis, the results show that the new bridge under the action of foundation settlement difference, longitudinal pier fulcrum position splicing under high horizontal stress, transverse middle fulcrum section splicing appeared transverse stress peak period of angular point position, may result in the crack of the concrete; There is a linear relationship between the level of additional internal force and the settlement difference of foundation, which is about 0.95MPa/mm. The calculation stress value of splicing segment can be reduced by reducing the thickness of splicing segment. In practical engineering, control and adjustment measures such as preloading of new bridge structure and selecting adjustable high support can be used to improve the force condition of splicing section[1][2].
Finite Element Analysis of PolyLactic Acid (PLA) under Tensile and Compressive Loading
Authors: Aldosari Fahad , Khan M. A. A. , Asad M. , Djavanroodi F.
Published: April 2023

Additive manufacturing or 3D-Printing technology is being utilized heavily in recent times, especially in a range of manufacturing industries. Many types and sizes of 3D-printers are being utilized in producing ceramic, metal, or plastic components. This technology is serving society in many aspects, such as minimizing environmental impact, reduction in cost, and even material consumption. Polylactic acid (PLA) is a thermoplastic filament type material used in Fused Deposition Modelling (FDM) 3D printers. In this study, finite element analysis is used to simulate the mechanical behaviour of PLA in both solid and a 60% infill conditions. Simulations are done to predict strength and other mechanical properties in both tensile and compressive loadings using ABAQUS. The results provide insight on the performance of PLA under above mentioned conditions. It is concluded the carefully selected infill pattern can result in less material consumption together with nearly same mechanical performance as the sound PLA objects.
Toughening and Strengthening Modification of Flame-Retardant High-Impact Polystyrene
Authors: Chen Yijun , Zang Chongguang , Zhu Xiangdong
Published: April 2023

In this study, to improve the flame-retardant and mechanical properties of high-impact polystyrene (HIPS), DBDPE/Sb2O3 and HBCD/DBDPE/Sb2O3 were used to modify HIPS for flame retardant, where HBCD/DBDPE played a synergistic role in the segmental flame retardant of HIPS. The mechanical properties of flame-retarded HIPS were improved through surface, toughening and reinforcement modification, while the flame-retardant level of HIPS was guaranteed at UL94V-0. The flame-retardant and mechanical properties of flame-retarded HIPS were characterized by tensile test, impact test, LOI, UL94, TGA, DTG, DSC. The results indicated that HIPS modified with HBCD/DBDPE/Sb2O3 achieved UL94V-0 (3.2 mm), and the LOI of the modified HIPS was nearly double that of unmodified HIPS. The mechanical properties of the modified HIPS were optimized when the particle size of Sb2O3 was 500 nm, and 2-3 wt% titanate coupling agent NDZ101 was added to the flame retardant. Compared with the flame-retarded HIPS modified without tougheners and reinforcements, the HIPS modified by 22%PPO and 15%SEBS was improved the tensile strength by 33.5%, the impact strength by two times, and reached the excellent flame resistance of UL94V-0.
Adsorption of Volatile Organic Compounds via Cellular Material Produced from Aluminum Dross
Authors: Chien Kuang-Li , Chen Chun-Liang , Liang Chih-Chao , Chuo Hsien-Ho , Yang Sheng-Fu
Published: April 2023

In this study, the aluminum dross collected in the production process of the aluminum smelting industry was used as the raw material for mixing with an alkaline solution to make aluminum hydroxide where aluminum was extracted by a titration procedure. When the pH value of the solution is 10~13, the crystal forms of the precipitation products are monoclinic and hexagonal, and the particle size is about 0.25~4 μm. To develop and establish a circular economy in the aluminum industry for aluminum smelting slag where aluminum hydroxide and alumina are environmentally friendly adsorption materials can help to solve environmental problems caused by waste, increase the life cycle of resources. Cellular material produced from aluminum dross are used to carry out the adsorption characteristics test of volatile organic compounds, and the average adsorption amounts for acetone and toluene were 1.20 and 1.87 μg/g, respectively. This cornerstone results had demonstrated the design and development of the expansion of resource-based adsorption materials can meet the needs of various industries.
Experimentally and Numerically Investigate of the Critical Diameter of Aluminized DNAN/RDX Melt-Cast Explosive
Authors: Cao Tongtang , Zhou Lin , Zhang Xiangrong
Published: April 2023

This study experimentally investigates the effect of RDX particle size and crystal quality, as well as aluminum particle size and content on the critical diameter of aluminized DNAN/RDX melt-cast explosive using the continuous wire method. Ultimately, the critical diameter increases when the particle size of both RDX and aluminum, as well as RDX crystal quality increases. Contrastingly, the critical diameter decreases when the aluminum content increases. Besides, we employed the Ignition and Growth reaction flow model to simulate the effect of RDX particle size and crystal quality, as well as aluminum particle size and content on the critical diameter.
Analysis of Low Mechanical Properties of 1420 Al-Li Alloy in Tensile Test
Authors: Liu Peishuo , Cheng Jun , Chen Hao , Yang Zhongwei , Li Yue
Published: April 2023

The mechanical properties of 1420 Al-Li alloy tensile specimen were tested after T6 heat treatment. The mechanical properties of some specimens were lower than the standard requirements. In this paper, the reasons for the low mechanical properties of tensile specimens were analyzed by means of electron microscope observation, metallographic examination and hardness examination. The results show that after T6 heat treatment, the surface of the sample is rough and the depth of the oxide layer is different, and the notch sensitivity of 1420 alloy is very high. During the mechanical properties testing, the deep oxide layer becomes the stress concentration point and the source zone of tensile fracture, which reduces the overall mechanical properties of the sample. After heat treatment, the surface of the specimen is formed with low hardness white bright band structure, which also reduces the mechanical properties of the specimen. The high content of Zr in the fracture source region of some samples also leads to the unqualified mechanical properties.
Failure Analysis of High Pressure Hose in Hydraulic Loading System
Authors: Li Yue , Bai Yan , Li Xiaolin , Liu Peishuo , Shi Changwei
Published: April 2023

During the low temperature static test of a certain model, the hose of the hydraulic system leaked oil and bulged. In this paper, through the macroscopic observation and analysis, anatomical observation and analysis, scanning electron microscope analysis and infrared spectrum analysis of the failed high-pressure hose, the reason for the failure of the high-pressure hose is obtained: due to the cracking failure of the inner rubber, the high-pressure oil in the pipe leaks outward, and the outer CPE material leaks or bulges locally. The reason for the cracking of the inner rubber is mainly related to two factors: 1) the inner steel wire winding layer of the hose is locally uneven, and there are bridging and overhead phenomena; 2) the inner rubber has low elongation and poor compatibility of deformation.
Study on Microstructures and Properties of the Al. Alloy Vacuum Die-Cast Parts of TL117 and C611
Authors: Han Lijun , Wu Xuesong , Zhu Junjie , Bai Ming , Zheng Xiaohong , Zhang Ze
Published: April 2023

The microstructures and properties of the vacuum die-cast Al. alloy C611 were studied by taking the vacuum die-cast Al. alloy TL117 as a reference. The purpose is to cancel the T6 heat treatment and part correction process in the die-cast Al. alloy production in order to reduce the cost of parts. By adding rare earth element Sr, the crystallization process and crystal morphology can be controlled, by which the grains can be refined and the phase transformation stress can be controlled properly. The strength and deformation of the part can meet the design requirements. By comparing the microstructures, second phases, strength, elongation, fracture morphologies and crystallization latent heat of the two materials, the mechanisms of high performance and small deformation of the C611 part were obtained. The research of the vacuum die-cast Al. alloy without heat treatment and correction is of great significance to the application of Al. alloys in automobile field.
Contact Electrification Characteristics of Polytetrafluoroethylene and Metal
Authors: Ding Ruihuan , Si Xiaoliang , Qu Minglei , Yan Wei , Li Qiuliang , Duan Zemin
Published: April 2023

In industrial production, the contact electrification phenomenon between materials will cause equipment damage and bring potential safety hazards to personnel, so it is necessary to study the contact electrification mechanism of materials. In order to explore the contact electrification characteristic mechanism between polytetrafluoroethylene and brass, aluminum alloy, a contact separation electrification test platform was built to pay attention to the change rule of surface potential of composite materials under contact pressure, environmental relative humidity, temperature and material temperature difference. The test results show that the surface potential first increases and then decreases slightly with the increase of contact pressure, and the surface potential is stable when the contact pressure is greater than 7 KN; The contact electrification of materials decreases with the increase of relative humidity; At 15°C ~35°C, the material surface potential is proportional to the temperature; With the temperature difference between the two test materials becoming larger, the contact potential shows a law of first increasing and then decreasing. Through the analysis of the contact electrification characteristics of materials under different conditions, it can provide a direction for further research on the contact electrification mechanism and industrial electrostatic protection.
Stress Analysis Around the Interference-fit Joint of CFRP/metal Stacks
Authors: Song Danlong , Wang Yuanhao , Yang Zhenchao , Hua Keyi
Published: April 2023

Carbon fibre reinforced polymer (CFRP) composites and traditional metal alloy are both widely applied in modern aircrafts. The mechanical performances between CFRP laminate and metal alloy are totally different, the stress of CFRP/metal stacks around the interference-fit joint is severely non-uniform. Therefore, the stress distribution for the contact interface of CFRP/metal stacks was investigated by finite element simulation in detail. First, the assembly process of the interference-fit bolt with CFRP/metal stacks was partitioned into six stages. Secondly, an accurate 3D finite element model was established by ABAQUS to simulate the hi-lock bolt interference fit assembly process with CFRP/metal stacks. Finally, the stress magnitude and distribution of interference-fit interface were compared and analysed. It was observed that the interference percentages and friction coefficient were the two major factors that affected the non-uniform stress distribution. The stress on the contact interface of the stacks was less than that on the free surface and decreased with moving away from the bolt.
The Thermal Insulation Composites for Lithium-ion Batteries
Authors: Cheng Chuan’ao , Zang Chongguang , Chen Yijun
Published: April 2023

In this paper, the high-efficiency thermal insulation composites were prepared and investigated, which are formed by the addition of hollow SiO2microspheres, hollow glass microspheres, and hollow phenolic microspheres into addition-type liquid silicone rubber. The thermal conductivity of composites is as low as 0.054 W/(m·K), which is 70.65% lower than the matrix (the thermal conductivity of the matrix is 0.184 W/(m·K)), and the tensile strength is 1.003 Mpa, and the thermal decomposition temperature of the composites is 427 °C .
Research on a Stone Processing Powder Recovery and Reuse Device
Authors: Gao Hua , Yu Aiyue , Lin Shengfeng , Huang Ying , Fu Congchun , Yang Kaihuai
Published: April 2023

This article focuses on a recycling device for powder from stone processing. The device mainly includes three components: a filter device, a rolling device and a gathering device. It could not only perform the filtration, rolling and gathering of stone powder, but also effectively prevent the collected stone powder from accumulating in a single place, and greatly improve the filtration efficiency. The device can be applied in the concrete prepared by artificial sand with distinct advantages in production energy consumption, production cost, and also has a superiority in the development, utilization and application scope of by-products, and recycling of raw materials, At the same time, it can reduce pollution to living environment greatly. The device is simple in structure, practical in use and easy to promote.
External Measurement System for Aircraft Structural Parts Based on Digital Image Correlation in Signal-limited Spaces
Authors: Cai Yusheng , Liu Yayan , Yang Chunxia , Zhu Ke , Liu Wencheng , Huang Jia , Zheng Pei , Zhang Keming
Published: April 2023

An experimental study was performed on the application of the digital image correlation (DIC) technique to characterize aircraft components for which accurate time information is required. This study builds an aircraft external measurement system based on Stereo DIC. This system obtains real-time satellite time information from a GPS clock source and transmits it to a trigger unit. A camera acquires this information and displays it on the image. This solves the problem that some closed laboratories can use only computer time and cannot obtain accurate satellite time when using camera measurements. Moreover, we verify the reliability and accuracy of this approach, finding an average angular accuracy of better than 0.02 degrees and a relative error of less than 1%. Using the binocular Stereo DIC system, the accuracy of the measurements is clarified for specific conditions. Furthermore, we use this system to measure simulated aircraft landing gear, which moves at an angular velocity of 52.4 °/ s over a distance of 5 m with a wide field of view of 16.8°. The satellite time information acquired by the camera and the time information of the captured time targets are highly stable. The system’s reliability is demonstrated for use in practical engineering, contributing to the engineering application of Stereo DIC for external aircraft measurements.
The Effect of Thermal Discharging on the Island Ecosystem in China: Current Knowledge and Future Challenges
Authors: Chen Junhui , Feng Aiping
Published: April 2023

The island ecosystem is composed of the island terrain, island bedrock, tidal flats, and shallow water. With the increasing of power plants along the coastline, the sea water surrounding the islands is warming. It remains a question the relation between the warming water and ecosystem health. In this study we have analysed many practical examples and found that each part of the ecosystem would be affected by the warming water. Currently, the undisclosed interaction mechanism between each part of the ecosystem and the lack of island ecological background data make it hard to assess the impact of thermal discharging quantitatively. The thermal discharge host can either apply for the island use right in warming areas or not based on the current laws in China. But the strict island utilization procedure bans any activity didn’t register in the use right application, which prohibits the flexibility to react to ecological damage in time. There is still a long way to go before the island in the warming waters achieve a balance between island protection and resource utilization.
Coupling Relationship Between Heat Waves and Air Pollution: A Case Study of Central Tianjin
Authors: Jiao Jiao , Chen Tian , Wang Qiao , Zang Xinyu
Published: April 2023

With the increasing contradiction between urban construction and ecological and societal resources, the impact of heat wave and air pollution on cities has become increasingly conspicuous. How to create a comfortable and cool urban environment has become a hot topic that the whole society attaches great importance to. By analyzing the spatio-temporal distribution of heat wave and air pollution, the coupling characteristics of heat wave and air pollution are obtained.
Speciation Analysis of Selenium in Several Different Marine Shellfishes
Authors: Deng Yueping , Huang Le , Liu Chunlan , Sun Yachen , Liu Lihua , Zhuang Min , Zheng Xuehong , Chen Ding
Published: April 2023

In this study, different shellfishes such as Mactra antiquate, Macoma truncata Jonas, Solen Grandis, Dosinorbis japonica, Meretrix meretrix, Sanguinolaria chinenss and Scapharca broughtonii were collected in the Chang-le Mussel resource protection Area, Fujian province. The contents of total selenium, inorganic selenium and organic selenium in different shellfishes were determined by hydride atomic fluorescence spectrometry. The results showed that the selenium contents in study area were in the middle, however, significant differences were found among different shellfishes. The total selenium contents of Solen Grandis was the highest (0.498~0.898 μg g−1), followed by Scapharca broughtonii (0.508 μg g−1) and Sanguinolaria chinenss (0.507 μg g−1). And the inorganic selenium of Scapharca broughtonii was the highest (0.229 μg g−1), followed by Solen Grandis (0.224 μg g−1) and Mactra antiquate (0.125 μg g−1). At most station, the proportion of organic selenium to total selenium in shellfishes was between 54.6% and 89.6%, indicating that organic selenium is the main form.
Drought Risk Assessment in China Based on Water Resources System
Authors: Yuan Zhe , Xu Jijun , Yan Dengming , Yao Liqiang , Sun Keke
Published: April 2023

Based on the risk theory, drought hazard, drought exposure and drought vulnerability were evaluated by precipitation, water consumption and water supply, respectively. A model of drought risk assessment method was thus proposed and it is finally applied in China. The results showed that the drought hazard index in the eastern monsoon region was higher, the drought exposure index in the Yangtze River Economic Belt, north China Plain, Heilongjiang Province, Inner Mongolia Autonomous Region and Xinjiang Autonomous Region was higher, the drought vulnerability in the southern region is higher. The middle and lower reaches of the Yangtze River, north China Plain, southwest China, Heilongjiang province in northeast China and Xinjiang Autonomous Region in northwest China are at high risk of drought.
Research on Energy Saving Technology of Air Energy Heat Pump Constant Temperature System in the Reconstruction of Swimming Pool Project
Authors: Chen Lingling , Dong Ruanjian , Liang Xiaohui
Published: April 2023

With the country’s emphasis on the popularization of compulsory education, many newly built primary and secondary schools have planned and designed swimming pools or swimming pools in recent years. In the process of putting the swimming pool into use, there are many problems, such as short service life and difficult maintenance. There are also some problems in the use of swimming pools, such as high operating cost and high maintenance cost. In this paper, the constant temperature system of air-energy heat pump in the renovation process of swimming pool or swimming pool in primary and secondary schools is studied, and the corresponding energy-saving technical suggestions are put forward to improve the utilization rate of swimming pool in primary and secondary schools.
Calculation of Risk Probability of Levee Landslide Based on Three-dimensional Lequilibrium Theory
Authors: Wang Fei , Zhang Guifang
Published: April 2023

Sliding instability is a common form of failure of embankments, and traditional dike safety evaluation often uses the safety factor value to judge whether it is safe or not. However, due to the uncertainty of the rock and soil characteristics of the embankment, the evaluation results of the safety factor method sometimes fail to reflect the reality, and it is reasonable to use the risk analysis of sliding instability considering these uncertainties. In this paper, the uncertainty of rock and soil strength parameters and the randomness of seepage field are considered, and the risk probability of sliding instability of the embankment is solved by relying on the reliability analysis method. In the reliability analysis, a three-dimensional bin method combining slope stability analysis and gradient optimization method of reliability analysis are proposed, which consider the safety performance, so that the stability evaluation is not too conservative, and the corresponding sliding risk probability can be obtained while obtaining reliable indicators. Finally, the calculation program is prepared for the proposed method, and the proposed method is verified to be reasonable and correct through the example.
Research on the Safety Management Mode of University Biological Laboratory by Strengthen the Cultivation of Independent Safety Awareness
Authors: Sun Liquan
Published: April 2023

College biological laboratory safety is an important part of biological safety. In addition to the safety problems of various reagents and equipment, there are also the protection and waste treatment of various plants, experimental animals, microorganisms and human tissues and organs used in the experiment. In college biological laboratories, the cultivation of independent safety awareness of laboratory personnel is weaker than that of biological enterprises, which leads to two kinds of frequent problem events led by safety protection and waste disposal in college biological laboratories in recent years. Starting from the safety of biological laboratory in Colleges and universities, this paper discusses the laboratory safety protection and waste treatment based on the cultivation of independent safety awareness of laboratory personnel.
Research on Renewal and Sustainable Development of Old Urban Blocks
Authors: Liang Xiaohui , Chen Lingling , Ye Yanbing , Wang Guang , Shen Wenjuan , Wang Yiran
Published: April 2023

From the perspective of urban renewal, this paper takes the old factory area of Liuzhou City as an example, and renovates and develops the old blocks that need to be replaced by functions. This work uses scientific theories to guide the renewal and transformation, and takes the principle of seeking truth from facts and people-oriented as the principle of renewal and transformation, and realizes the transformation and renewal through various means. In addition, the culture of workers has been reshaped, the industrial memory has been revived, and the importance of renovation and sustainable development of old urban districts has been clearly explained, all of which meet the requirements of urban ecology and green, healthy and sustainable development.
Causes of Cold Condensation and Durability Countermeasures of Concrete Structures in Caverns
Authors: Zhang Zhipeng , Peng Yiyang , Fang Xiao’ai , Chen Qi , Gan Weizhong
Published: April 2023

Moisture condensation often occurs in the cave wall in service, which results in the deterioration of the internal environment of the cavern and the decline of its functionality and durability. In this paper, the corrosion mechanism of concrete structure caused by the dew-condensation inside the cavern wall is analyzed, the daily temperature and humidity environment change inside and outside the cavern is measured, the influence of wind speed and ventilation condition on the dew-condensation inside the cavern is discussed, and the change rule of the external atmosphere temperature, the air temperature and humidity inside the cavern wall temperature is discussed. The results show that it is an inevitable physical phenomenon that the internal temperature of the cavern is lower than the dew point temperature, and the measures to deal with cold condensation such as sealing the cave with dry gas when no one is around, filling the cavern with air of appropriate temperature and humidity when there are people, and setting up dehumidification system are effective ways to improve the durability of the concrete structure of the cavern.
Research on Heat and Mass Transfer Performance of Corrugated Coils in Closed Cooling Towers
Authors: Cui Pengfei , Zhou Shuo , Wu Anbing , Geng Man , Luo Hanhua , Li Jianjun
Published: April 2023

According to the characteristics of the flow in the corrugated pipe, Fluent is used to simulate the 3D numerical simulation of the fluid in the corrugated pipe and the ordinary straight pipe by using the RNG k-ε model. Water at a certain temperature is used as the medium. The flow velocity is 0.5 m/s, 0.75 m/s, 1 m/s, 1.25 m/s, 1.5 m/s, in-pipe characteristics with a pipe diameter of 25mm and a pipe length of 1030mm. The simulation adopts the unstructured hexahedral mesh in the simulation, and the SIMPLE algorithm is used for pressure correction; the algebraic equation is iteratively solved by the over-relaxation method. The temperature and velocity at different cross-sections when the flow and heat exchange enter the fully developed stage are obtained through simulation calculation, and they are compared with the related characteristics of flow and heat transfer in the light pipe. The cooling tower of the straight pipe is tested, and the results show that the heat transfer performance of the corrugated pipe is better than that of the ordinary straight pipe.
Study on Energy Storage and Cost Saving Scheme of Traction Substation
Authors: Liu Yujuan , Ding Tao
Published: April 2023

Based on the energy-saving and economical operation requirements of high-speed railways, the traction power supply system adopts large-capacity energy storage devices. The paper takes the measured data of a traction substation as an example to compare the energy-saving effects of the two energy storage schemes and give suggestions.
Land Reclamation and Governance in Dongda Mining Area
Authors: Ma Jian
Published: April 2023

The south areaof Shandong Province is an important base of coal production in China. With the gradual depletion of coal resources, the destruction and abandonment of land in the mining area is very serious, greatly affecting the production and life of people around the mining area. The study of land reclamation and management in mining areas has become extremely urgent. In order to strengthen the reclamation and management of the land in the mining area, this paper, based on the current situation of the surface subsidence and land damage in the mining area of Dongda Coal Mine, and the analysis of the impact on the ecological environment, discusses the methods and measures of land reclamation in the mining area in detail. The findings of the paper will provide important insights into the surface subsidence and land reclamation and management in other mining areas.
Research on the Circulation Strategy of Agricultural Products under Extreme Weather
Authors: Ma Linlin , Chen Zhongye , Li Yanrong
Published: April 2023

The influence of extreme weather on the circulation of agricultural products is mainly reflected in: the contradiction between supply and demand caused by the change of the yield and quality of agricultural products under extreme weather, and the security threat of agricultural products caused by the block of circulation under extreme weather. This paper further analyzes and summarizes three aspects of agricultural products circulation strategies under extreme weather, including: formulating emergency methods for extreme weather agricultural products circulation under extreme value thinking, constructing climate-wise agricultural products circulation system, and improving the agricultural products circulation service system under the national unified market.
Self-sacrifice Stainless Steel Mesh derived FeNi-MOF Materials as Water Splitting Electrocatalyst
Authors: Zhong Li , Wang Ni , Hu Wencheng
Published: April 2023

The oxygen evolution on the anode electrode, the most prominent half-cell reaction all through the water-splitting procedure, is primarily hampered and limited by sluggish dynamics and low reaction efficiency. This work provides an interesting research idea. By utilizing recycled resources as precursors, followed by in-situ hydrothermal method, micron-sized single Metal-organic frameworks (MOF) crystals were rapidly prepared. The as-obtained MOF crystals FeNiBDC exhibited an improving electrocatalytic OER performance with a small overpotential of 334 mV (η10: 10 mA cm−2), a Tafel slope of 100.2 mV dec−1, and a relatively low resistance of 8.13 Ω, compared with the precursor of stainless-steel mesh.
Risk Assessment Model of Carbon Emission Market Trading in Pilot Cities Based on Entropy Weight-TOPSIS Method
Authors: Zhang Fubo , Li Xue , Liang Xiaolong , Li Mingpeng , Ao Jin , Li Qian
Published: April 2023

As an emerging trading mechanism, the carbon market has been widely promoted and paid attention to. On the basis of analyzing the current status of carbon emission market trading in my country’s current pilot cities, this paper considers 12 risk evaluation indicators from four dimensions of external risk, transaction risk, operational risk and management risk, and uses the entropy weight-TOPSIS method to establish a pilot city carbon emissions. Market transaction risk evaluation model, select the pilot city of Guangzhou to carry out empirical analysis. The results show that the operational risk has a greater impact on the pilot cities, and the corresponding risk evaluation indicators should be managed in order to improve my country’s carbon emission market system.
Bacterial Communities Structure and Diversity in Rhizosphere Soil of Dominant Plants in Riparian Wetlands of Reservoir in Zhejiang Province, China
Authors: Chen Haisheng , Chen Taolue , Zhu Zhaoping , Cai Linsheng , Luo Wen , Huang Xiaoyu , Zeng Hongxue , Zhu Youchong
Published: April 2023

Soil bacterial play special roles in the maintenance and stabilization of wetland ecosystem. To investigate bacterial community structure and diversity in rhizosphere soils of four dominant plants in riparian wetlands of mountain reservoir in Zhejiang province, the V4+V5 areas of 16S rDNA gene of bacteria were sequenced and analyzed by the Illumina HiSeq 2500 high-throughput sequencing technology. The results indicated that 27 phylums, 70 classes, 144 orders, 218 families, and 370 genuses of bacteria were achieved, with Proteobacteria, Acidobacteria,Actinobacteria and Bacteroidetes being the dominant phylum and Gammaproteobacteria, Deltaproteobacteria, Acidobacteria, Actinobacteria, Betaproteobacteria and Thermoleophilia being the main class in the soils of riparian wetlands in this areas. The Shannon index and chao1 index of the rhizosphere soil bacteria of Salix babylonica were 8.64 and 585.58, respectively, which were the highest among the four plants, and that of Pterocarya stenoptera were the lowest, with 7.71 and 289.63, respectively. Soil pH, total nitrogen and organic matter were the main factors affecting the soil bacterial community structure in the soil rhizosphere of four dominant plants species in wetlands of riparian zone of reservoir in Zhejiang province.
Defrosting Characteristics of the Cockpit Windshield of Manned Airships
Authors: Wang Yansong , Liu Meinan , Li Yonghao , Kong Benben , Chen Jiamin
Published: April 2023

Frost covering of the cockpit windshield will seriously obstruct the driver’s vision and even affect flight safety of the low-altitude manned airship. To solve the problem, this paper proposes a rapid defrosting strategy using hot gas injection method. The influences of the air inlet type, air temperature, air velocity and air angle on the defrosting characteristics of the transparent windshield are investigated and the defrost characteristics of the manned airship are obtained by fluid dynamics simulation. The result shows: (1) Defrosting effect of single inlet is not as good as double inlets. The defrosting area of the double inlet is relatively large, mainly concentrated at both ends of the windshield. (2) The effect of air supply temperature on defrosting effect of windshield surface is more significant when double air supply inlets are used. But when the air supply temperature reaches a certain value and continues to rise, the defrosting time does not change much, so there is an optimal air supply temperature range. (3) The higher the air supply velocity is, the shorter the phase transformation time of frost layer is and the faster the melting velocity is. Considering energy consumption and defrosting characteristics, the optimal air supply velocity is about 6 m/s. (4) When the angle between the air supply direction and the horizontal plane of the bridge near the windshield is 100°, the frost layer has the shortest melting time.
Techniques of Reservoir Sediment Release and the Application
Authors: Zhou Yinjun , Gao Yu , Fu Jing , Zhou Caijin
Published: April 2023

A series of questions of reservoir sediment deposition have always been a hot issue of common concern. The world has carried out extensive research on it to improve the basin sediment distribution, resource allocation, ecological environment and other issues. The paper summarizes the basic principles of various techniques for reservoir sediment release, and several typical reservoirs at home and abroad have been selected as the case to elaborate that its main measures and effect of the sediment removal. It also makes a comment on the development trend which can be used for the research and practice of the reservoir and lake sedimentation control and restoration.
Analysis on the Characteristics of Climate Change in Erhai Lake from 1956 to 2018
Authors: Shan Yonghua , Xing Jitao , Sun Keke
Published: April 2023

The Erhai Lake in Southwest China is not only an ecologically fragile area but also a vulnerable area from climate change. In order to deal with climate change, the characteristics of precipitation, temperature and evapotranspiration of Erhai Lake were investigated by trend analysis methods, periodicity analysis methods and abrupt change analysis methods. The results showed that: During the period 2006 to 2018, average precipitation and temperature in Dali Station changed by -10% and +0.76°C, respectively, compared with before 2006. It is expected that the variation of precipitation in the future is not significant. However, the trend of temperature change is consistent with the current situation and will show an increasing trend. Under the influence of temperature rise, evapotranspiration showed an obvious increasing trend and it will continue to increase with temperature rise in the future. The primary period for the changes of precipitation, temperature and evapotranspiration were 30a, 20~25a and 10~20a. The abrupt change points of precipitation and temperature were approximately 2005, while the abrupt change point of evapotranspiration in 1980s.
Formation Process and Driving Mechanism of Urban Waterlogging in the Greater Bay Area
Authors: Chen Yilong , Xu Zhong , Liu Junxiang , Xu Zibo , Fan Weinan
Published: April 2023

With the acceleration of the urbanization process, the degree of “hardening” of the urban surface becomes higher, and the storage capacity is weakened seriously, so it is easy to cause urban waterlogging. Doing a good job in urban flood control and waterlogging control and reducing disaster losses has become the top priority of disaster prevention and mitigation in our country in the 21st century. This study takes the Chebeichong watershed in Guangzhou as the research area, and based on quantitative observation data, summarizes the formation mechanism of urban waterlogging in the Guangdong-Hong Kong-Macao Greater Bay Area(GBA), and proposes the key driving factors for the formation of urban waterlogging in the GBA. It will provide theoretical and technical support for the study of effective urban waterlogging forecasting methods.
Corrosion Cause Analysis of a Surface Pipeline Flange
Authors: Ji Nan , Li Changliang , Wang Peng , Zhu Lijuan , Feng Chun
Published: April 2023

Corrosion was found on the inner wall and sealing groove end face of a surface pipeline flange in an oilfield in western China after one year’s service. Corrosion causes were investigated by physical and chemical property tests, metallographic examination, scanning electron microscope, scanning electron microscopy(SEM) inspection, energy disperse spectroscopy(EDS) analysis and X-ray diffraction(XRD) analysis. The results showed that the chemical composition and mechanical properties of the flange were all in accordance with the corresponding parameter requirements, and the corrosion phenomenon was mainly attributed to CO2 corrosion. High temperature and high medium flow rate also had a big influence on the acceleration of the corrosion process. Corrosion of the sealing groove end face was attributed to galvanic corrosion, the corrosion potential difference between the flange and gasket was the main reason for the galvanic corrosion.