bluuebunny/crossref_metadata_2025 huggingface dataset:
Risks of neonatal anomalies and obstetric complications in 7378 singleton births after frozen–thawed and fresh embryo transfers in Japan: An analysis using doubly robust estimation
Authors: Terada Sanae , Habara Toshihiro , Terada Ryo , Mitsuhashi Toshiharu , So Ryuhei , Yoshioka Nanako , Masumoto Yumi , Kosaka Yukiko , Hirata Rei , Hayashi Nobuyoshi
Published: January 2025

Purpose

To compare risks of neonatal anomalies and obstetric complications among frozen–thawed embryo transfer (FET), fresh embryo transfer (FreshET), and non‐assisted reproductive technology (non‐ART) treatments in infertile women.

Methods

This retrospective cohort study analyzed 7378 singleton births (2643 non‐ART, 4219 FET, 516 FreshET) from 2013 to 2022. Outcomes were compared using inverse probability weighting regression adjustment, with adjustment for maternal factors.

Results

After adjustment, the risk of neonatal anomalies did not differ significantly between FET and non‐ART, or FreshET and non‐ART. FET was associated with increased risks of obstetric complications compared with non‐ART, including placenta accreta (adjusted risk difference [ARD] 3.61%, 95% CI 2.95–4.28), placenta previa (ARD 0.55%, 95% CI 0.14–0.96), postpartum hemorrhage (ARD 7.08%, 95% CI 6.03–8.13), gestational hypertension (ARD 3.57%, 95% CI 2.47–4.68), gestational diabetes (ARD 0.96%, 95% CI 0.17–1.75), and preterm birth (ARD 2.13%, 95% CI 1.23–3.02). FET also showed higher risk of high birth weight (ARD 0.97%, 95% CI 0.42–1.52). FreshET showed no significant differences in obstetric complications.

Conclusions

While the risk of neonatal anomalies did not differ among treatments, FET was associated with increased obstetric complication risks. These findings underscore the need for careful management of FET pregnancies and further research to improve treatment protocols.
Efficient Path Following Control Design for Tractor With Multiple Trailers Systems Utilizing Movement Rules and Passive Multi‐Steering Angles
Authors: Zhou Yusheng
Published: January 2025

This paper proposes a straightforward and robust control strategy for a tractor with multiple trailers system (TMTS, for short) to effectively follow identical paths. Hereto, the control design is structured into four steps for path‐tracking precision. Firstly, a suitable passive steering angle is assigned to each trailer, granting it some steering capability to follow the moving path of its direct leader. Secondly, movement rules of the TMTS with passive multi‐steering angles are explored in‐depth for the first time, facilitating the convenient deduction of kinematic and dynamic models. Thirdly, a desired movement task of the TMTS is reduced to a tracking control by the tractor through the implementation of suitable passive steering angles. Additionally, by virtue of a curvature tracking method, cumulative location errors could be greatly reduced by tracking the relative curvature. Fourthly, a combination of feedback linearization, optimal control, and integral sliding mode control methods is employed to design two driven torques for the tractor to precisely follow the geometric path. Consequently, both the tractor and all trailers are capable of simultaneously following an identical path. In the end, numerical simulations are presented to demonstrate the effectiveness, feasibility, and robustness of the resulting control strategy for practical applications.
Fluvio‐hydrological characteristics and diverse bedrock geology control the dynamic growth, truncation, and amalgamation of bedrock streambed and marine potholes
Authors: Bera Biswajit , Bhattacharjee Sumana , Mukhopadhyay Uttam , Sengupta Debasis , Shit Pravat Kumar , Sengupta Nairita , Ghosh Supriya , Ghosh Arijit , Saha Soumik , Sarkar Sudipa
Published: January 2025

A total of 393 potholes (368 fluvial and 25 marine potholes) were studied at seven different sites in both the fluvial and marine environments. Diverse bedrock properties and large‐scale delivery of tools and grinders regulate the dynamic growth, truncation, and amalgamation of potholes. Therefore, the principal objectives of the study are (i) to examine the relationship between the growth of potholes and substrate lithological with structural characteristics (applying geospatial and Schmidt hammer for rock strength analysis) and (ii) to measure the morphology, and size of tools and grinders, processes of truncation and amalgamation in hydro‐geomorphic environment using various indices and field techniques. The result showed that large potholes are stretched in the direction of lineament axes and roughly parallel to the river flow direction. Here, the steady growth of pothole depth‐diameter is controlled by active bedrock structures, tools, or grinders, and monsoonal high‐velocity bank full discharge. Consequently, the deepening and widening of potholes are relatively slow at Bindu, Deuli, and marine beach Neil Island due to fewer structures and little supply of tools or grinders. In small stretches, (Damodar, Subarnarekha, and Rarhu) canyons and gorge‐like features (bedrock incision) are formed at Rajrappa, Bhakuyadi, and Guridih sites due to cyclic truncation and amalgamation. Truncation and amalgamation processes restrict the vertical depth threshold value of potholes within 3 m, particularly at Rajrappa, Bhakuyadi, and Guridih sites. Scientific study of the pothole's dynamic growth is greatly necessary for the different environmental engineering and river hydraulic projects like excavation, dredging, and dam or barrage construction. Successively, it is essential to compute the cost of rock excavation or dredging, primarily for the mechanical strength of the bedrock river channel and its stability.
Classifying Global Economies Based on Sustainable Development Goals: A Data‐Driven Clustering Approach
Authors: Jena Soumyaranjan , Basel Sayel
Published: January 2025

The concept of sustainable development gained global prominence after its widespread recognition and the establishment of the United Nations' 2015 sustainable development goals (SDGs). These goals aim to tackle the issues of poverty, inequality, and environmental sustainability by 2030. This study utilizes machine learning clustering techniques, namely, Grey Relational Analysis and K‐means clustering, to classify 167 countries based on their SDG performance between 2000 and 2024. The analysis identifies four clusters, with Cluster 3 demonstrating the strongest overall performance. An ordered logit model is used to assess which SDGs mostly influence cluster membership, revealing that tailored policy interventions are crucial for addressing different countries' development challenges. This approach offers a dynamic perspective on the global SDG progress and enables more targeted and effective policy‐making toward attaining the 2030 Agenda.
When the rich do (not) trust the (newly) rich: Experimental evidence on the effects of positive random shocks in the trust game
Authors: Bejarano Hernan , Gillet Joris , Rodriguez‐Lara Ismael
Published: January 2025

We study behavior in a trust game where first‐movers initially have a higher endowment than second‐movers but the occurrence of a positive random shock can eliminate this inequality by increasing the endowment of the second‐mover before the decision of the first‐mover. We find that second‐movers return less (i.e., they are less trustworthy) when they have a lower endowment than first‐movers, compared with the case in which first and second‐movers have the same endowment. In addition, second‐movers who experience the positive shock return more than second‐movers who have the same endowment as the first‐mover from the outset. First‐movers do not seem to anticipate this behavior from second‐movers. They send less to second‐movers who benefited from a shock. Our findings suggest that in addition to the distribution of the endowments the source of this distribution plays an important role in determining the levels of trust and trustworthiness.
Vakuum‐Isolierglas mit passiver und aktiver Sicherheit
Authors: Weimar Thorsten , Reißaus Henrik , Hammer Christian
Published: January 2025

Der Eindruck von Leichtigkeit und Transparenz durch die Verwendung von Glas in Gebäuden führt zu einem stetig wachsenden Einsatz in der Fassade. Gleichzeitig steigen aber auch die Anforderungen an den Wärmeschutz von Gebäuden sowie das Bedürfnis nach Sicherheit durch die Nutzer. Dem Stand der Technik entspricht die Verwendung von Dreischeiben‐Isoliergläsern, die in Verbindung mit zusätzlichen Schichten aktive und passive Sicherheitsanforderungen erfüllen. Allerdings resultieren daraus ein deutlich höheres Eigengewicht sowie größere Gesamtdicken der Verglasungsaufbauten verbunden mit einer hohen Beanspruchung von Beschlägen und Rahmen. Insbesondere für das Bauen im Bestand ist dadurch der Einsatz in vorhandenen Rahmen häufig nicht möglich. Das in einem Forschungsprojekt am Lehrstuhl für Tragkonstruktion der Universität Siegen entwickelte Vakuum‐Isolierglas mit passiver und aktiver Sicherheit verbindet höchste Anforderungen an den Wärmeschutz sowie die Sicherheit mit einem leichten und schlanken Verglasungsaufbau. Die Kombination von Dünnglas und Polycarbonat sowie einer neuartigen polymeren Zwischenschicht mit dem Vakuum‐Isolierglas erfüllt die Anforderungen an Verbundsicherheitsglas und erreicht die höchste Widerstandsklasse P8B gegen manuellen Angriff als Sicherheitssonderverglasung. Durch den Einsatz von Vakuum‐Isolierglas im Verglasungsaufbau werden bei deutlich reduzierter Gesamtdicke vergleichbare Eigenschaften im Wärmeschutz wie mit einem Dreischeiben‐Isolierglas erreicht.
Climatic variation affects seasonal survival of an alpine bird species
Authors: Eriksen Lasse Frost , Harald Ringsby Thor , Israelsen Markus F. , Moa Pål F. , Grøtan Vidar , Nilsen Erlend B.
Published: January 2025

Mountains are particularly exposed to climate change, and empirical studies have shown that montane bird species are highly sensitive to the ongoing changes. Modelling mortality risks under climatic variation will give insight into species‐specific sensitivity. Willow ptarmigan Lagopus l. lagopus is a common resident species in many northern alpine ecosystems, with an important role in predator–prey dynamics. Willow ptarmigan moult into white feathers during autumn, which provides camouflage in the winter snow. With shorter periods of snow cover, a phenological mismatch between snow cover and moulting time may affect mortality risk. Simultaneously, snow cover may affect mortality risk through limiting the access to nutrient‐rich food and increasing risk‐taking. Detailed relationships between snow cover and mortality risk require high‐resolution data to uncover. We collected data from willow ptarmigan (n = 272) equipped with VHF transmitters over seven years in central Norway. Field data collection was performed on a monthly basis, except in the darkest period of winter. Using Cox proportional hazards models, we estimated whether variation in mortality risk was related to variation in snow cover in the spring and autumn seasons. We found that an earlier arrival of winter led to increased mortality risk for yearlings, but not adults, in the following spring. Further, spring mortality was lower when there was less snow in the spring. In autumn, mortality risk differed only between sexes. In our study we have shown that spring survival in a common montane species is affected by climatic variation, where the magnitude of effects on population dynamics will depend on the age distribution in the population. We hypothesise that there are competing risks connected with a moulting mismatch versus increased risk‐taking under limited access to food resources, that may have different importance under different conditions.
ADAMANT: Hardware-Accelerated Query Processing Made Easy
Authors: Broneske David , Burtsev Vitalii , Drewes Anna , Gurumurthy Bala , Pionteck Thilo , Saake Gunter
Published: January 2025

We present ADAMANT, an adaptive data management architecture for evolving heterogeneous hardware/software systems. The ADAMANT system enables plug’n’play integration of co-processors such as GPUs and FPGAs, provides a unified runtime that supports cross-device parallelization of SQL query execution on arbitrary co-processors at runtime, and supports multi-query processing. We discuss the concepts behind and performance of ADAMANT following an example query (TPC-H Q6), present different execution models for cross-device execution, and provide an FPGA hardware architecture that allows the implementation of query-specific hardware accelerators at runtime. In addition, we introduce a new approach for approximate query processing for FPGAs. Our performance analysis concludes that the use of hardware accelerators and device-specific implementations of query operators as part of a common system can provide significant speedups over state-of-the-art query execution engines.
Managing Very Large Datasets on Directly Attached NVMe Arrays
Authors: Haas Gabriel , Alhomssi Adnan , Leis Viktor
Published: January 2025

High-performance solid-state drives based on flash memory have replaced hard disks as the primary storage medium. Modern servers can host ten or more NVMe SSDs, and the aggregate bandwidth is approaching main memory bandwidth. In response to this evolution, this project evaluates the performance trade-offs posed by the abstraction layers and interfaces involved in I/O management. We experimentally slice through the software stack, exploring the limits of how efficient I/O can be done, and provide a discussion about durability. Finally, we discuss the implications of fast storage devices on the architecture and implementation of database storage engines. Overall, our work shows that exploiting the full potential of modern NVMe storage arrays is achievable but requires substantial engineering effort.
Design and Analysis of an Obstacle Dismantling Robot
Authors: Liu Shuai , Qiu Zhaopeng
Published: January 2025

ROBOTAC is a Chinese original national-level robot competition that combines the fun of sports competitions with the technicality of technology competitions. The competition is based on robot design and production, and the participating teams consist of multiple robots, which compete in a confrontational form. The 2023 ROBOTAC Mission Challenge requires the production of obstacle removal robots to clear the obstacles on the barrier platform. Based on mechanical principles design and control board production, this article introduces a successful obstacle removal robot that won the first prize in the national competition when coordinated with other robots.
Analysis of the Influence of Braking Performance in Different Positions of Heavy Duty Train
Authors: Zhao Jixian , Chen Chunjun , Song Liquan
Published: January 2025

In order to study the difference of gas flow state in front and rear train air brake system caused by pressure drop transfer time and pressure drop wave attenuation due to resistance during braking of heavy duty train, the 3D CAD model of the 120 type control valve was established using SOLIDWORKS software, based on the actual size. Train No. 42 and No. 56 were taken as examples (2DF8B + 54C80 + 2HXN3). By applying the operational principles of the type 120 control valve, the flow field during its first stage, second stage, and auxiliary cylinder brake stage were extracted. Pressure boundary conditions for both front and back train pipes were sequentially loaded into the flow field along with a Reliable

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turbulence model. In this paper, the differences in the control valve, auxiliary air cylinder and gas state parameters in the brake cylinder caused by the different positions of the front and rear trains are studied, which provides guidance for modeling and longitudinal impulse calculation of train air brake system.
Thermal Analysis and Simulation of Protective Cover for Power Devices of BeiDou Antenna
Authors: Liu Huisen , Zhai Xiongzhi , Hou Yuelin , Jin Biyao , Liu Zhaolei , Liu Jun
Published: January 2025

Beidou antennas have been widely applied in transportation and other fields, facing complex and varying environmental conditions. Therefore, the variability of BeiDou antenna power device protective cover under different working conditions carries important research significance. Aiming at exploring the thermal analysis of the protective cover under different working powers, the paper adopts finite element analysis to study the protection cover for Beidou antenna power devices in various working power conditions. Through the analysis of thermal field distribution, static strain distribution, and stress distribution of the protective cover, this paper explores methods to enhance working efficiency and prolong the service life of power devices.
Research on Hydraulic Support Handling Device for Rapid Excavation
Authors: Zhu Aixiang , Yin Fenglan , Jia Yongmin
Published: January 2025

Aiming at the problems of long handling time, high labor intensity, low handling efficiency, and inapplicability to the handling of newly developed temporary support hydraulic braces in rocky roadway, a hydraulic brace handling device matching with high efficient tunneling equipment for digging and anchoring parallel operation is introduced, and the relevant technical parameters, main structure and characteristics, hydraulic system, key technologies of the hydraulic brace handling device are specifically introduced. Through finite element analysis and calculation, the stress level of hydraulic bracket handling device in handling bracket is analyzed in detail, and the correctness of the finite element analysis is verified by comparing with the test data, and it is proved in practice that the device has the outstanding advantages of mechanization of bracket handling, hydraulic automation, short lifting cycle, high efficiency, etc., which improves the start-up rate of the roadheader and reduces the labor intensity of the workers.
Structural Design of a Two-Stage Hand Rehabilitation Exoskeleton
Authors: Chen Xianglei , Xia Kang , Zhou Jianfang , Sun Han , Wang Yimin
Published: January 2025

With the increasing aging population in China and the trend of younger onset of elderly diseases, more middle-aged and elderly people are suffering from stroke and related complications. Considering the increasing needs in rehabilitation service, exoskeletons for rehabilitation training have become a urgent solution. This article starts by analyzing the finger skeleton and designs a dorsal-style hand exoskeleton which assists patients in individual rehabilitation training for each finger, enabling them to perform simple grasping activities in daily life. Moreover, by using a single active driver, the exoskeleton can systematically drive the two adjacent joints of a patient's finger, ensuring that their movement aligns with the typical grasping patterns of a healthy individual. This design is more beneficial for the patient's rehabilitation. Finally, a comparison is made between the range of motion of the finger in a healthy state and when wearing the exoskeleton to ensure the safety of the exoskeleton.
Fault Diagnosis and Simulation Testing of Electrical Equipment Based on Machine Learning Algorithms
Authors: Li Chenyu
Published: January 2025

Electrical equipment and the stable operation of the power system have a close connection; qualified electrical equipment can ensure the normal operation of the power system. The electrical fault factors are numerous, and it is necessary to carry out early discovery and early resolution of electrical faults. Based on this, this paper analyzes an electrical equipment fault diagnosis system using machine learning algorithms, and at the same time conducts simulation experiments on the performance of the system, and its results show that the diagnosis system proposed in this paper can shorten the detection time and improve the detection accuracy. It is expected that the research in this paper can provide a corresponding basis for the efficient diagnosis of electrical equipment faults.
Integrated Importance Measure Method for the Whole Life Cycle of Typical Polymorphic Hybrid System
Authors: Dong Zhonghui
Published: January 2025

In response to the identification of weak components within the life cycle of a mixed-connection system, this paper first extends the calculation method and properties of the Integrated Importance Measure (IIM) from a single time point to the entire life cycle. The extended IIM can identify components that have the greatest impact on the system during different periods or throughout the entire life cycle. Based on this, the paper provides the calculation formulas for the IIM of polymorphic series–parallel and parallel-series connection systems for component failure processes. Finally, the practicality of the extended importance measure formula is verified through numerical simulation.
Thermal Impact Analysis of Brake Discs Under Extreme Working Conditions of Trackless Trains Based on Virtual Testing
Authors: Li Huaming , Xia Mingchen , Zheng Shize , Ding Jingxian
Published: January 2025

Trackless trains adopt public right-of-way. The braking distance requirements are strict, and large deceleration is required to stop the train. Brake disc is an important part of the trackless train, its service performance directly affects the braking safety of the train, and the temperature and stress are the key performance parameters. In order to investigate the influence law of variable working conditions on the temperature and stress of the brake disc, for the problem that it is difficult to simulate the extreme working conditions based on the real measurement method, the brake disc of a 3-vehicle and 6-axle trackless train is taken as the research object. According to the structural dimensions and material parameters, a thermo-mechanical coupling simulation model of the brake disc is established based on the theories of transient thermodynamics and heat transfer. Based on the standard comparison analysis, the deceleration index of the trackless train to meet the requirements of braking distance is designed, and the virtual test of the temperature and stress field of the brake disc is carried out under the conditions of different loads, deceleration, and ramp gradient. The results show that it is feasible to simulate the extreme working conditions based on the virtual test, and the maximum temperature and stress of the brake disc increase with the increase of load, deceleration and ramp gradient. Under the extreme working conditions, the maximum temperature of the brake disc is about 680.4 ℃, and the maximum stress is about 1240 MPa. The research results provide a reference for the safe operation and maintenance of the trackless train.
Experimental Study of the Effect of Temperature on the Resistance of SOFC Stainless Steel Bipolar Plate
Authors: Wei Renshan , Cui Huanyong , Zhang Yican , Xu Jing , Zeng Wensheng , Li Fajia , Liu Haining
Published: January 2025

Stainless steel bipolar plates play a key role in solid oxide fuel cells as a supporting part of solid oxide fuel cells. In order to obtain the variation of the resistance of nickel–cobalt-coated stainless steel bipolar plates with temperature, a measurement test platform for the resistance of high-temperature bipolar plates was built, and the resistance of the bipolar plates with temperature was measured by the four-terminal resistance measurement method, and the resistance values of the solid oxide fuel cell bipolar plates at different temperatures were measured. The results show that the resistance of the stainless steel bipolar plate specimen of solid oxide fuel cell gradually decreases during the temperature increase. When the temperature of the solid oxide fuel cell stainless steel bipolar plate specimen is increased to 800 °C, the resistance value is 0.6 Ω and the resistivity is 0.24 Ω m.
Structure Design of a Corner Protection Injection Mold
Authors: Li Zhanfeng , Chen Guangjuan
Published: January 2025

Aiming at the process characteristics of a high-end home decoration—corner protectors, while satisfying the functional requirements, and considering the optimization of the product appearance design. A reasonable injection mold structure design scheme is selected. The design process of the injection mold, special side core-pulling design points of double-side sliders, injection forming process and feeding mode, etc. are analyzed. Finally, after processing and assembling each component, a second trial mold production is carried out, and the qualified plastic parts are successfully produced. The surface quality of the plastic parts is good and the mechanical properties are higher.
Design and Realization of Defrost and Icebreaking Device for Cryogenic Connector of a Certain Rocket
Authors: Tong Fei , He Huan , Song Tao , Zhang Li , Lin Yiyong
Published: January 2025

In this paper, aiming at the shortcomings of the current defrosting and icebreaking device of a certain type of rocket cryogenic connector, a new type of rocket cryogenic connector defrost and icebreaker is designed by analyzing the frost generation mechanism on the surface of the low-temperature connector and the influence of ice on the connector shedding and secondary docking, The installation location, structural shape and size specifications of the new device were designed through the analysis of the key defrosting and icebreaking parts on the cryogenic connector. According to the requirements of defrosting and icebreaking of low-temperature connectors during the filling process and temperature return before secondary docking, the air supply flow, gas supply pressure and temperature indicators were set after experimental data and simulation model calculation. Experimental verification shows that the new defrosting and icebreaking device can improve the reliability of low-temperature connector falling off and ensure the safety and effectiveness of secondary docking.
Crashworthiness Design of the Lower Support of the Cargo Compartment of Civil Aircrafts
Authors: Chen Chen
Published: January 2025

The lower part of the cargo floor support is the key part of the aircraft that absorbs energy after contacting with the ground firstly in the process of crash, which is an important index of the crashworthiness of the aircraft. In this paper, based on the transient dynamics explicit integration algorithm and finite element analysis method, finite element analysis is carried out to analyse the nonlinear process of the structural deformation of the support member in the crash. The results show that the peak acceleration at the centre of the floor can be reduced by reducing the thickness of the strut to improve its crashworthiness. The width of the edge strip of the brace and the angle of the outer support of the brace have little effect on the deformation of the bottom of the fuselage and the peak acceleration at the centre of the floor.
Structural Design and Feasibility Analysis of a Double-Rotor Wheeled Wall-Climbing Robot
Authors: Peng Fangfang , Yu Baojun , Guo Yongyi , Jiang Hancheng
Published: January 2025

In this paper, a double-rotor wheeled wall climbing robot is designed and a new transition method is proposed. The wall-climbing robot is using the counter-thrust force generated when the rotor rotates at high speed as the adsorption force, so that the robot can adsorb stably on the wall without slipping and tilting and can realize the transition from the ground to the vertical wall. The forces of the robot in different motion states were analyzed, and the overall structure of the robot was verified to meet the strength requirements by setting appropriate loads through finite element simulation. By numerical simulation of the aerodynamic characteristics of a single rotor when rotating, the pressure on the upper and lower surfaces of the rotor and the surrounding velocity vector, and the feasibility that the robot can be stably adsorbed to a vertical wall is verified.
Design of Rectangular Part Layout Optimization System Based on Standard Dimension
Authors: Ji Jun , Huang Dun-Hua , Xing Fei-Fei , Chen Xin
Published: January 2025

In many industries of the national economy, the problem of material optimization layout will be encountered. In this paper, the layout problem of two-dimensional guillotine-cutting stock is studied, and the related concepts of the same-shape block and the same-shape section are proposed. To improve the efficiency of layout, the standard dimension of same-shape block and the standard dimension of same-shape section are proposed. By applying the standard dimension, the calculation speed and the efficiency of the algorithm will be improved effectively.
Design of Technological Process and Control System for Multi Station Stacking Equipment
Authors: Deng Cheng-Gang , Zhou Shu-Yu
Published: January 2025

In order to realize the automation of the stacking production line in the spinning workshop, a translational multi station stacking process was designed, the moving path of the gripper of the stacking equipment was optimized, and the overlapping stroke action was set to improve the stacking efficiency. The design scheme of multi position stacking equipment control system is put forward, and the automatic stacking process of cheese under four-axis linkage is realized by using the principle of three-dimensional positioning and equipped with servo system. The average time of single stacking is less than 54 s, which meets the efficiency requirements of the production line, and provides a practical reference for the automation and intelligence of the spinning workshop.
Optimized Design of Guide Vanes for Vertical Upwelling in Marine Ranching: A Three-Dimensional Numerical Analysis
Authors: Chen Nan , Li Dongfeng , Rong Qinhuan , Mo Kui , Wu Yaer , Zhang Heshun , Bai Fuqing , Hu Jianyong , Wei Ziyang , Lin Feiyu
Published: January 2025

Marine ranching holds significant potential for improving the marine ecological environment. The artificial upwelling technology and devices employed within it contribute to enhancing the marine carbon sink, strengthening the aquatic biological pump, and promoting fisheries resource proliferation. Therefore, this study focuses on the guide vanes of artificial upwelling devices, investigating the role of optimized guide vanes in vertical upwelling efficiency. Through three-dimensional numerical simulations, the performance of these optimized guide vanes is analyzed to provide insights for practical applications.
Design of Ceramic Conical Cover Assembly Equipment
Authors: Lu Zhuowen , Wu Changzhong , Chu Daying , Hou Zhihao
Published: January 2025

Ceramic cone is an important part of the aircraft, and its component installation accuracy is very important. In view of the low degree of automation in this field, this paper proposes a new type of ceramic cone bonding assembly equipment to replace manual bonding assembly of ceramic cone and Invar connecting ring. The overall structure and function of the equipment and the assembly process were introduced with the help of Solidworks 3D drawing software. The cone-housing positioning of self-centering chuck + servo adjusting seat and the non-contact measurement scheme of multi-station and multi-section can be measured were adopted. The reasonableness of the assembly effect was verified by the production of a prototype.
Structure Design and Simulation Analysis of a Load Acquisition Encoder
Authors: Shang Shijie , Li Guofu , Li Haitao , Chen Wenbo
Published: January 2025

In response to the problems of large volume and poor reliability of traditional acquisition encoder, the author designs a load acquisition encoder. Combined with the simulation method, the internal and external structure of the acquisition encoder is deeply analyzed from two dimensions of mechanics and heat. It ensures the integrity and reliability of the functional performance when the volume is reduced, and further verifies the rationality of the structural design of the equipment, good vibration resistance and heat dissipation performance. It can meet the practical engineering needs, and has certain reference significance for the same type of product design.
Design of Automatic Feed Packaging Machine with Robotic Arm
Authors: Peng Peiming , Zheng Weilin , Tan Xiaolan , Tang Lianyao , Wang Yage
Published: January 2025

According to the current market demand, the operation mode of manual packaging products is inefficient. In order to improve production efficiency and reduce the labor and time cost of packaging operations, this paper designs a product packaging machine that can be used for pellet feed. Feeding is realized through the feeding mechanism of the packaging machine. The feed is automatically packed by the bag feeding mechanism and sealing device, and finally the product is sent to the designated place through belt transmission, and an ABB robot is used for handling and palletizing. The whole machine can achieve continuous work, so that the packaging process can run automatically and efficiently, reduce production costs, and bring higher benefits to actual production.
Design and Implementation of Intelligent Coupled Rearview Mirror Variable Position Structure
Authors: Liu Jinghui , Xu Tongqiang , Du Guangfu , Wu Liying
Published: January 2025

In view of the shortcomings of the traditional optical rearview mirror, such as the existence of blind zone, rain weather, snow weather and night vision observation are not effective and the wind resistance coefficient of automobile at high speed is large, which affects fuel economy and other problems. Because the reliability of electronic rearview mirrors is lower than that of traditional rearview mirrors. Therefore, a coupled variable position intelligent rearview mirror is designed. It has both the structure of traditional optical rearview mirror and the image processing ability of electronic rearview mirror. Under the condition of satisfying the driver's visual habits, it can effectively improve the visual effects of different scenes, and improve the reliability and driving safety of the car. By designing the displacement mechanism, the information display mechanism can be folded into the cab. It can effectively reduce the air resistance and wind noise when the car is driving at high speed. It can improve the fuel economy and NVH performance of automobiles. By using SolidWorks to carry out three-dimensional design and motion simulation, it is proved that there is no interference in the motion process of the displacement mechanism. It can realize automatic displacement according to different situations, and it has human-computer interaction ability and a higher degree of intelligence.
Modelling the Thermal Characteristics of a Machine Tool with External Mechanical Spindle Motor
Authors: Shi Kai , Yang Rui , Gao Weiguo , Zheng Yingjie , Hu Gaofeng , Weng Lingtao , Fu Yutao , Wang Pengkai
Published: January 2025

For machine tools with external mechanical spindle motor, there is a significant problem: when the traditional finite element (FE) model is used for thermal characteristic analysis, the test and the simulation results are significantly different. This leads to low reliability in the forward design and thermal balance design of machine tools by the traditional FE model. Therefore, this paper proposes the thermal characteristic analysis (TCA) model that allows various heat transfer modes and heat generation of the feed system in the enabling state. Then, the FE analysis results are compared and analyzed by constructing the thermal characteristic testbed. The results show that the temperature and deformation fields obtained by the two methods are generally consistent, which proves that the constructed TCA model can quickly and accurately obtain the thermal performance of the machine tool with external mechanical spindle.
A Method for Reconstructing Three-Dimensional Structure of Nasal Cavity Based on a Short-Source Acoustic Tube
Authors: Lian Xiaoqin , Wang Yuqiao , Gao Chao , Li Jin , Ma Guochun , Wang Zitong , Bao Kexin
Published: January 2025

The reconstruction of the three-dimensional structure of the nasal cavity is significant for the diagnosis and treatment of nasal and nasopharynx diseases. This study proposes a method for reconstructing the three-dimensional structure of the nasal cavity based on the short-source acoustic tube, which addresses the inconvenient portability and high cost of the long-source acoustic tube. Firstly, we separate incident and reflected waves based on the propagation characteristics of pulsed acoustic waves in a short-source acoustic tube. Secondly, to reduce the error in calculating the input impulse response sequence, the methods of correcting the direct current (DC) offset component and suppressing the high-frequency noise are used to pre-process the nasal acoustic signals. Finally, we adopt the layered reconstruction method of the three-dimensional structure of the nasal cavity to reconstruct the depth cross-sectional area two-dimensional curve and take a three-dimensional visualization. Through comparative analysis, this method can meet practical application requirements.
Analysis of the Influence of Preload Loading Deviation of Pitch Bearing Bolt Group on the Contact Stress of Rolling Elements
Authors: Ouyang Weijin , Zhao Bing , Qiao Yueqi , Li Heng , Deng Dingshan , Zhang Shen
Published: January 2025

This paper aims to study the influence of bolt preload distribution on structural performance in the bolted connection structure model of pitch bearings of wind turbines. The preload application deviation and the change of contact stress of the rolling element of the pitch bearing were analyzed by finite element modeling. The results show that the bolt preload loading deviation will cause the rolling element contact stress of the pitch bearing to fluctuate, and the rolling element contact stress near the blade is greater than the rolling element contact stress far away from the blade. In the case of large fluctuations in preload, the contact stress fluctuations of the lower rolling elements are more affected. Therefore, in order to extend the working life of pitch bearings, the bolt preload should be precisely controlled during assembly.
Modal Analysis of Mobile Platform of Tea Garden Management Machine in Hilly and Mountainous Areas
Authors: Zhang Yanzun , Xiao Jiacheng , Yin Yuxing
Published: January 2025

In order to verify the rationality of vibration design of mobile platform, a modal analysis method based on ANSYS is designed. Firstly, the natural frequency of the mobile platform is simulated and analyzed according to the three-dimensional digital model. Then, the external excitation value of the mobile platform is obtained by theoretical calculation method. Through analysis, it can be seen that the mobile platform does not generate resonance under normal working conditions, so the design of the mobile platform meets the vibration requirements.
Optimization of Structural Parameters of Vortex Type Coiled Tubing Drag Reduction Tool Based on Coanda Effect
Authors: Xue Xianbo , Hua Zejun , Liu Haijun , Zhang Chengcheng , Qu Yue , Zhu Xiaohua , Shi Changshuai , Cheng Feilong , Luo Dongjing
Published: January 2025

The vortex drag reduction tool based on wall attachment effect has a simple structure and high reliability, but lacks systematic research on tool structural parameters. In the application of coiled tubing drilling, there are problems such as poor parameter matching and weak power output. Therefore, based on the theory of wall attached jet, this article establishes a numerical model of vortex drag reduction tools, and investigates the effects of wedge distance, sidewall angle, wedge angle, and flow channel width on the oscillation performance of the tools. The research results indicate that the wedge distance and the angle between the sidewalls affect the oscillation frequency generated by the tool by affecting the jet deflection angle, the wedge angle affects the fluid flow velocity and vortex strength in the vortex chamber, and the flow passage affects the switching of the attached wall jet by affecting the pressure on both sides of the jet port. When the splitting distance is greater than 40 mm, the angle between the sidewalls is 30°, the width of the flow passage is 4–5 mm, and the angle between the splitting tips is 15°, the oscillation performance generated by the tool is better. The research results have certain guiding significance for the reasonable matching and optimization design of the structural parameters of eddy current drag reduction tools.
Analysis of the Launch Dynamics of All-Terrain Rocket Artillery Under Ice Conditions
Authors: Li Fan , Yu Cungui
Published: January 2025

In order to study the launch performance of rocket artillery in alpine areas, a multi-body dynamic model of all-terrain rocket artillery was established, the interaction model between ice surface and ice surface was established by using the finite element method, the interaction force between orbit and ice surface was obtained, and the launch performance of all-terrain rocket under the ice surface was calculated by using the multi-body dynamics model. The results show that the modeling method can well simulate the interaction between the track and the ice surface, and the all-terrain rocket launcher has good launch performance on the ice surface.
Numerical Analysis Model of Contact Stress in the Raceway of Double Row Tapered Roller Bearing Under Overturning Torque in Wind Turbine
Authors: Li Chang , Wu Wensong , Du Jing , Wang Shuang , Jiang Shuxin , Sun Weiwei
Published: January 2025

This article extends the force analysis of the single rolling element in the whole double row tapered roller bearing to the establishment of a global static equilibrium equation. And further analyzes the position relationship between the roller and the raceway after deflection under overturning torque. Based on non-Hertz line contact theory and bearing force balance equation, a numerical analysis model for the contact stress of the raceway in a double row tapered roller bearing is proposed; To verify this model, a local finite element model of bearing contact was established based on ANSYS to obtain the stress distribution of the raceway. The results show that the stress calculation model for wind turbine spindle double row tapered roller bearings under overturning torque proposed in this paper has good simulation accuracy.
Microstructure of AZ31B Alloy Induced by Laser Shock
Authors: Li Xiangyu , Ma Baoji , Liu Bin , Cao Jinkui , Li Liangliang
Published: January 2025

Magnesium alloys have great potential in the field of biomedical degradable materials. However, their poor mechanical and corrosion resistance properties limit their applications. In this study, the AZ31B alloy with a compact hexagonal close-packed (HCP) crystal structure was selected as the material, as it tends to undergo twinning deformation rather than dislocation slip during plastic deformation due to its low stacking fault energy. The microstructures before and after LSP treatment were characterized using optical microscopy (OM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD). The results showed that the grain size was refined and exhibited a gradient distribution after LSP treatment. Electron backscatter diffraction (EBSD) was used to characterize the microstructure of LSP before and after treatment. The results showed that the grain size was refined after LSP treatment, and showed a gradient distribution trend.
Analysis of Factors Influencing the Tension Change of Electrode Wire in High Speed Wire Cutting
Authors: Ge Suxia , Wang Lili
Published: January 2025

The electrode wire for EDM wire cutting is not a rigid body, which is affected by external forces during processing, resulting in fluctuations in the tension value of the electrode wire, which causes the electrode wire to break, thus resulting in the reduction of machining accuracy. In order to improve the machining accuracy of the parts, the factors affecting the change of electrode wire tension are analyzed, the main influencing factors are derived, and the necessary measures are taken to make the corresponding adjustments to reduce the adverse effects of the fluctuation of tension value.
Numerical Simulation Analysis of Flow Control Effect of Harbor Seal Whisker Model Under Different Reynolds Numbers
Authors: Wu Yaer , Li Dongfeng , Chen Nan , Rong Qinhuan , Mo Kui , Zhang Heshun , Bai Fuqing , Hu Jianyong , Wei Ziyang , Xuan Zhentao
Published: January 2025

This article uses CFD calculations to numerically simulate the wake field of the spotted seal whisker model, combines the plane vorticity distribution diagrams of the cylindrical and elliptical cylinder models and analyzes according to the criteria, and observes the tail flow of the spotted seal whisker structure model under different Reynolds number conditions. The flow field is used to reveal its flow characteristics and flow control effect. It can be seen that this structure can reduce drag and suppress lift fluctuations, and has better effects under low Reynolds number conditions.
Design and Control of Tendon-Driven Dexterous Hands
Authors: Guo Minggao , Liu Yang , Wang Yage
Published: January 2025

Based on the structural characteristics of the human hand, a tendon-driven dexterous hand was designed. Starting from the transmission and structure aspects of the dexterous hand, the structural design scheme of the dexterous hand under tendon-driven transmission was studied. Then, the kinematics of the fingers were derived, and finally, grasping experiments of the dexterous hand were conducted. The results showed that the designed dexterous hand could achieve stable and reliable grasping of regular objects.
Optimization of Damping Groove Parameters of Swashplate Plunger Pump Based on CATIA Secondary Development
Authors: Tan Jianping , Han Kunpeng , Liu Yao , Huang Xiaoxuan , Lin Erte
Published: January 2025

In order to improve the performance of the plunger pump, aiming at the problems of flow pulsation and pressure overshoot of the plunger pump, a new compound slot flow distribution buffer tank structure is proposed. CATIA modeling software is used to obtain the overflow area curve of the valve plate through Boolean operation. Through the secondary development of the software, the overflow area curve of the valve plate under different parameter values can be obtained efficiently. Then the pressure, flow and other related parameters of the pump can be observed in the AMESim model of the plunger pump. The results show that the flow pulsation and pressure overshoot can be effectively reduced when the depth Angle is 7°, the width Angle is 90° and the composite aperture is 0.8 mm.
Simulation of the Back-Side Cracking of Nickel-Based Superalloy Turbine Blades with Eddy Current Testing
Authors: Yuan Jia , Lei Zihao , Xue Xinhai , Chen Hongen , Wen Guangrui , Su Yu , Chen Xuefeng
Published: January 2025

Cracks may occur in the back of turbine blades during the manufacturing process, which may cause potential safety hazards to the aero-engine. To design proper probes for detecting the back-side crack, this paper builds a finite-element model for eddy current detection of cracks on the back of the nickel-based superalloy plate, which are often used to produce blades. The influence of coil parameters and crack parameters on eddy current signal is investigated. The results show how to choose the proper parameters of a coil and how crack parameters affect eddy current signals.