bluuebunny/crossref_metadata_2025_split huggingface dataset:
Key comparison BIPM.RI(I)-K3 of the air-kerma standards of the GUM, Poland, and the BIPM in medium-energy x-rays
Authors: Burns D T , Kessler C , Michalik Ł 
Published: August 2021

Main text
A key comparison has been made between the air-kerma standards of the GUM and the BIPM in the medium-energy x-ray range. The results show the standards to be in agreement at the level of the expanded uncertainty of the comparison of 6.0 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database.
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Improving the ripple classification in focal pediatric epilepsy: identifying pathological high-frequency oscillations by Gaussian mixture model clustering
Authors: Migliorelli Carolina , Romero Sergio , Bachiller Alejandro , Aparicio Javier , Alonso Joan F , Mañanas Miguel A , Antonio-Arce Victoria San 
Published: August 2021

Abstract

Objective. High-frequency oscillations (HFOs) have emerged as a promising clinical biomarker for presurgical evaluation in childhood epilepsy. HFOs are commonly classified in stereo-encephalography as ripples (80–200 Hz) and fast ripples (200–500 Hz). Ripples are less specific and not so directly associated with epileptogenic activity because of their physiological and pathological origin. The aim of this paper is to distinguish HFOs in the ripple band and to improve the evaluation of the epileptogenic zone (EZ). Approach. This study constitutes a novel modeling approach evaluated in ten patients from Sant Joan de Deu Pediatric Hospital (Barcelona, Spain), with clearly-defined seizure onset zones (SOZ) during presurgical evaluation. A subject-by-subject basis analysis is proposed: a probabilistic Gaussian mixture model (GMM) based on the combination of specific ripple features is applied for estimating physiological and pathological ripple subpopulations. Main Results. Clear pathological and physiological ripples are identified. Features differ considerably among patients showing within-subject variability, suggesting that individual models are more appropriate than a traditional whole-population approach. The difference in rates inside and outside the SOZ for pathological ripples is significantly higher than when considering all the ripples. These significant differences also appear in signal segments without epileptiform activity. Pathological ripple rates show a sharp decline from SOZ to non-SOZ contacts and a gradual decrease with distance. Significance. This novel individual GMM approach improves ripple classification and helps to refine the delineation of the EZ, as well as being appropriate to investigate the interaction of epileptogenic and propagation networks.
Research progress of air-cooled heat dissipation technology
Authors: Chen Jinmao , Sun Yanli , Hu Junbiao , Zhou Lijie , Wang Xudong 
Published: August 2021

Abstract
Air cooling is a kind of cooling method, which uses air as a medium to cool objects that need to be cooled. It is usual to increase the surface area of the object that needs to be cooled, or to increase the rate of air flowing through the object per unit time, or to use the two methods. In recent years, there have been some emerging technologies that improve the heat dissipation efficiency by improving the heat transfer efficiency of the air-cooled front end. Based on the analysis of the current research trend of air-cooled heat dissipation technology, a detailed review of typical air-cooled heat dissipation technologies from three aspects of materials, structure and emerging technologies is expected to provide relevant references for the further research and optimization of laser wireless energy transfer technology.
Research on local compensation technology of large diameter steel pipe with heterogeneous structure and analysis of application
Authors: Zhao Kexin , Yang Yongmin 
Published: August 2021

Abstract
When large-diameter steel pipes have special structures with stiffening rings, grouting holes, etc., the electrostatic spray epoxy powder anti-corrosion process is likely to produce large temperature differences due to the sudden thickness changes during heating, which cannot meet the temperature requirements of powder spraying. This paper designs a set of automatic temperature compensation technology for large-diameter steel pipes with stiffening rings and grouting holes, which aims to solve the problem of uneven heating of stiffening rings and grouting holes in the medium frequency induction heating powder spraying process. Through the method of “intermediate frequency heating + stiffening ring temperature compensation”, the inner and outer parts of the steel pipe are heated evenly and the temperature difference is reduced. The temperature difference between the inner wall of the steel pipe is reduced to 3∼15°C in the area of the stiffening ring, and the temperature is reduced in the area of the grouting hole. The difference is reduced from 70°C to 57°C to 20°C, the temperature difference is controlled within the allowable range of technical requirements, and the temperature compensation effect is good. The process has the advantages of simple device structure, high work efficiency, and small temperature difference in the spraying area, and is suitable for use on similar large-diameter steel pipes or other hydraulic metal structures.
Research on the method of skateboard edge grinding by combination of robot and pneumatic constant force grinding device
Authors: Yao Maoyun , Zheng Changwan , Wang Zihao , Qian Jiangzhong , Xi Qiang , Kuang Shaolong 
Published: August 2021

Abstract
The paper presents a method of robot skateboard edging grinding based on pneumatic constant force device. To solve the problem of modeling and complex algorithm of robot end active compliance control during the grinding process, a hybrid position/force control is proposed by controlling position and force separately. That is, a kind of 2 degrees of freedom pneumatic constant force grinding device is designed to realize the constant force control in the horizontal and vertical directions, while a robot is used only for position control. Then a fuzzy PID control algorithm is proposed for smooth grinding based on the dynamic modeling of the grinding device. Experiments show that the use of fuzzy PID can effectively improve the dynamic adjustment performance of the pneumatic constant force grinding system and reduce the steady-state error. Compared with normal PID, fuzzy PID reduces the step response adjustment time of the grinding system from 400ms to within 200ms. In addition, when the constant force control is disturbed, the response adjustment time is less than 100ms and there is no oscillation, and the standard deviation of the grinding force is within 1N, which has good robustness and fulfills the requirements of edging control.
Rotating machinery weak fault signal detection method based on QPSO and stochastic resonance
Authors: Gao Kangping , Xu Xinxin , Zhang Hui , Shi Ning , Jiang Xin , Shang Xiaofei , Jiao Shengjie 
Published: August 2021

Abstract
Due to the weak early vibration signal of rotating machinery, which is nonlinear and non-stationary, the traditional filtering method has some limitations. To this end, a weak signal detection method combining Quantum Particle Swarm Optimization (QPSO) and Stochastic Resonance (SR) is proposed. First, according to the adiabatic approximation theory, make the original signal meet the SR requirements, and optimize the structural parameters of the SR through QPSO; secondly, the signal-to-noise ratio is used as the objective function to make the input signal and the output signal achieve the best match; finally, simulation and experimental data are used to verify the feasibility of the proposed method. Comparative analysis shows that the proposed method increases the amplitude by 46% compared with the characteristic frequency obtained by the PSO optimized SR model.
Thermal characteristic of double-row cylindrical roller bearing of high-speed train using analytical solution and finite element analysis
Authors: Zhang Kai , Hu Hanping , Liu Xiaojie 
Published: August 2021

Abstract
The complicated thermal characteristics critically affect the reliability of double-row cylindrical roller bearing (DCRB) in the high-speed railway, which will cause the deformation and vibration and severely lead to bearing failure. Thus, research on the heat distribution and steady temperature field is essential for DCRB. In this paper, the Green’s function was established and programed with MATLAB under certain boundary conditions to verify the temperature field of DCRB. It computes fast than the finite element analysis (FEA), According to the simulation of ANSYS, temperature in outer ring is higher than inner ring and it is the maximum in roller, while the rib reduces the temperature in bearing and temperature near rib is larger, which result in asymmetry in raceway. All these results are consistent with the accrual working. This paper provided a heat portion equation between the rollers and the raceway and calculated more accurate and comprehensive than other equation. All results in this paper made sure the more exact temperature field in the DCRB with more convenient calculation and verification.
Analysis and research on failure of B-phase lower bridge arm through wall casing in converter station
Authors: Zhang Shuai , Zheng Wenzhe , Fang Zheng , He Jian , Lin Haofan , Fang Chengwei , Lin Jingtao , Wei Bo , Song Guoquan 
Published: August 2021

Abstract
Based on the actual failure of the bushing, this paper conducts analysis and research. Firstly, it analyzes the protection action, on-site harmonic components, bushing structure and disassembly step by step. Then it conducts the research on the discharge and breakdown characteristics of epoxy insulation. Finally, we results show that there are bubbles or impurities in the outer capacitor layer of the capacitor core inside the casing, and the harmonic content is higher under the operating conditions of the converter station. Meanwhile, we gives some relevant suggestions for the through-wall bushing in the design and manufacturing stage to consider relevant harmonic factors are of certain significance to extend the life of the bushing.
Deep transfer attention network for intelligent fault diagnosis of rolling bearings
Authors: Li Shihao , Jia Feng , Shen Jianjun , Ma Junxing 
Published: August 2021

Abstract
Deep learning based on fault diagnosis methods of rolling bearings has attracted much attention with the rapid development of artificial intelligence. However, these methods trained by bearing datasets from one equipment cannot be well applied to correctly identify the fault information of the bearing datasets from another equipment. The main reason for this problem is that the datasets from the different equipment have different probability distributions. In order to solve the above problem, a deep transfer attention network is proposed for intelligent fault diagnosis of the rolling bearings. The steps of this method are listed as follows. Firstly, the feature extraction network is used to extract the features from different bearing datasets. Secondly, the different transfer attention is given to different areas of the sample data by the attention mechanism and distribution differences among the features is reduced by domain adaptation. Finally, the fault recognition network is trained to identify fault status for different bearings. The proposed method is verified by using fault datasets from different bearings equipment. The results show that the proposed method can achieve the fault identification of different bearings equipment.
Fluid-structure coupling analysis of inlet ball valve on pumped-storage power station under extreme conditions
Authors: Liu Chang , Zhou Jianzhong , Duan Ran , Liu Ye , He Yanxi 
Published: August 2021

Abstract
While pumped storage power stations (PSPSs) provide clean energy, they are also facing many problems of safe operation. Inlet ball valves bear the brunt of the impact and disturbance from upstream pressure pipeline under extreme conditions on PSPSs. Artificially change the wicket gate and ball valve closing laws can improve the extremums of key indicators. However, the internal flow field in ball valves is complex, and the internal flow field interacts with the external structure. The performance impact studied only by the indicators of the ball valve inlet and outlet is far from enough. In this study, three-dimensional flow field simulation of an inlet ball valve on PSPS was carried out, and the Realizable k-ε turbulence model was selected to simulate the pressure and velocity changes of the flow field inside the ball valve under load rejection conditions. Based on the theory of fluid-structure coupling and CFX dynamic grid, the response characteristics of the ball valve mechanical structure after being subjected to transient flow field were studied, the distribution of related performance parameters of the structure was obtained, and the mechanism that causes stress, strain and total deformation was analyzed. This study found that the ball valve structure is significantly affected by the three-dimensional transient flow of water under extreme conditions of load rejection. The safety of the ball valve can be enhanced by setting expansion joints and strengthening the base.
Development and implementation on torsional vibration measurement of rotational machinery’s shaft
Authors: Yang Zixuan , Wang Zhifang , Wang Xuan 
Published: August 2021

Abstract
The measurement and analysis on torsional vibration is an important aspect to research the performance state of rotating machinery’s shaft. This paper introduces the basic procedure of torsional vibration measurement, deduces the manifestation of torsional vibration signal, focuses on the hardware design and software implementation of torsional vibration measurement system, and applies the measurement system to a certain type of ship and steam turbine generator shaft in actual testing. The measurement results verify the practicability and accuracy of the system.
Performance and application of an evaluation method for flow conditioner based on CFD
Authors: Wan Yong , Wu Bo , Lu Jiamin 
Published: August 2021

Abstract
As evaluation of the performance of flow conditioner mostly depends on the specific pipeline system, which cannot be timely feedback to improve the structure design, an evaluation method for flow conditioner based on computational fluid dynamics (CFD) is promoted. First, the evaluation coordinates for flow conditioner is established and the coordinate values of each sampling point are solved. Then, the judgment basis of whether the velocity distribution of pipe cross-section is fully developed is derived, and then come to the evaluation index of flow conditioner rectifier performance. Finally, with CFD simulation technology, the verified experiments of grid format flow conditioner are performed. The results showed that, the proposed evaluation method is qualified to evaluate the grid format flow conditioner’s performance quickly and effectively. Besides, it is helpful to analyze the function of flow conditioner’s performance on Reynolds numbers. What’s more, when 5.84 × 106≤Re≤5.84×108, the required minimum length of straight pipe for irregular downstream field of the grid format conditioner achieving fully developed is only 0.5-0.6 times by those without conditioner. It is of great significance to accelerate the flow conditioner designed and to promote fluid energy monitoring.
Finite element analysis and optimization design of beam structure of forging press
Authors: Ji Xin , Liao Shanmei , Zhang Xiaoyan , Gao Xiaoyong , Ma Ruiyang 
Published: August 2021

Abstract
The structural optimization design of 20Mn forging hydraulic press was studied. Firstly, the structure and stress characteristics of the hydraulic press are analyzed, then according to the center load condition, the static structure of the frame is simulated by finite element method, so as to understand the stress and stress concentration of each part, and achieve the purpose of checking the strength and stiffness of each part. On the basis of the above analysis, the strength of the beam is optimized on the basis of reducing the overall stiffness. The simulation results show that the optimized design scheme can reduce the material consumption and save the cost.
Topology Optimization of an aircraft engine gearbox
Authors: Wattananaphakaseam Nuz , Sittisang Natthasit , Phengsalae Napat , Dipasquale Daniele 
Published: August 2021

Abstract
Topology Optimization (TO) is a mathematical method extensively employed to optimize material layout within the design space, for a given set of boundary conditions with the goal of maximizing the performance of the system. This process takes a three-dimensional design space and whittles material away within it to achieve the most efficient design. Currently, engineers use this mathematical approach at a concept level of a design process, leading to results which are often fine-tuned for manufacturability. In some cases, the optimized geometry can be directly manufactured using additive manufacturing, indeed, TO is a key part of design for additive manufacturing. This work aims to apply TO in order to minimize the mass of an engine gearbox while maintaining an acceptable mechanical performance when compared to the original design. Numerical simulations are carried out by means of CAD and FEM software in order to improve the design of an aircraft gearbox composed of four gears, therefore, irrelevant parts of material are removed in the design space to meet the goal of minimizing the mass of the gearbox. The application of TO allows to obtain a better, lighter, and more efficient design of the gearbox by keeping its mechanical performance unchanged.
Heat transfer enhancement in a rectangular channel with pillars
Authors: Jiao Feng , Li Chengzhe , Dai Songjiang , Hu Meilin , He Yongqing 
Published: August 2021

Abstract
This paper numerically studied the heat transfer performance of water flowing in a rectangular channel with pillar structures. We systematically investigated the influence of the pitch, inclination angle, shape, and pillar arrangement on the flow and heat transfer characteristics. The results show that adopting spacing with S/d=2 can improve heat transfer performance sufficiently for a low Reynolds number case. Meanwhile, the noticeable enhancement can also be observed by making the pillar inclination direction consistent with the flow direction or staggered rhombic-shaped.
Numbering method for the kinematic chain isomorphism recognition of a planar mechanism
Authors: Tian Qing , Wei Xiaohui , Li Cai , Liu Ge , Deng Yumei 
Published: August 2021

Abstract
The kinematic chain isomorphism identification of a planar mechanism is an important part of the innovative design of kinematic chain regeneration. Based on the structural characteristics of the kinematic chain of a planar mechanism, a new method, i.e. the numbering method, is proposed for isomorphism identification. Firstly, the links of a kinematic chain are numbered according to certain rules, and they are normalized. Then, the normalized contracted link adjacency matrix is used to represent the connection of the kinematic chain graph. Based on whether the contracted link adjacency matrix of two kinematic chains is the same, we can judge whether the two links are similar.
Optimization of safety valve block of the pitch mechanism of bucket wheel stacker reclaimer
Authors: Guo Ziqing , Zhu Xuebiao , Wang Maoan 
Published: August 2021

Abstract
The luffing mechanism of the 6# stacker-reclaimer (DQ3000/4200) of an iron-making plant has malfunctions in production. After analyzing the fault reason of the original pitching mechanism. We optimize the hydraulic mechanism for solving these problems, and established a 3D model for the optimization part. The original hydraulic system and the improved hydraulic system model were established under AMEsim. The purpose of this study was to compare the movement speed of the hydraulic cylinder piston under different set pressures of the pressure valve to verify the improved hydraulic system meets production needs.
Support vector machine-based sound pressure extrapolation to overcome the finite aperture used in nearfield acoustic holography
Authors: Zhou Hefeng , Zhao Yun , Gao Dongbao , Tian Zhangfu , Zeng Xinwu , Jiang Weikang 
Published: August 2021

Abstract
Sound pressure extrapolation based on support vector machine (SVM) is proposed in order to reduce the reconstruction error in Fourier-based nearfield acoustic holography (NAH) when the aperture is small compared to the source size. The measured pressure on the aperture is introduced into SVM and then a regression model is obtained to extrapolate the sound pressure outside the aperture. Numerical simulations show that the new method allows a relatively accurate and quick reconstruction in comparison with the results using zero-padding and linear predictive border-padding.
Study on variation of thermodynamic parameters in vehicle-mounted LNG gas cylinder under static state
Authors: Huang Si , Yi Tiankun , Guo Jiawei , Yang Gang , Xia Li 
Published: August 2021

Abstract
To study the variation regularities of the mass, evaporation, temperature, and pressure of LNG in the gas cylinder with time, LNG was used as the working medium, and three specifications of LNG gas cylinders (150L, 330L, and 450L) were selected for heat transfer calculation. For the liquefied medium in the LNG gas cylinders, a saturated homogeneous model was adopted. For the heat transfer calculation of the adiabatic layer of LNG gas cylinders, a multilayer insulation structure model of radiation and heat conduction was adopted. According to the thermodynamic relations in the saturated state, the relations between the temperature and the physical parameters of the liquefied medium were fitted. The calculation method and calculation model were verified by the experimental data of liquid nitrogen for three specifications of LNG cylinders (150L, 330L, and 450L). According to the calculation model, the variation regularities of LNG thermodynamic parameters with time were obtained at a normal temperature. In the initial period of evaporation, the increasing temperature rate of LNG, the evaporating rate of LNG, and the pressure-boost rate of LNG in the gas cylinder are slow, and then these rates increase. The final mass of boil-off gas (BOG) produced by the phase change finally reaches 0.68% of the total mass of the medium in the gas cylinder.
An AMESIM-based simulation of hydraulic system design for ultra-high pressure tablet presses
Authors: Feng Kailin , Deng Bihai , Zha Chuanzhen 
Published: August 2021

Abstract
Aiming at the problems of large bore of hydraulic cylinders of high tonnage quantity tablet press, large size of tablet press and wide area, a method of using ultra-high pressure hydraulic system to streamline the structure of tablet press is proposed, and a laboratory ultra-high pressure tablet press for XRF spectral analysis specimen manufacturing is designed. The AMESIM software was used to simulate the established hydraulic system model, and the theoretical analysis and relevant experience were combined to reasonably set the relevant parameters of the simulation model, and the AMESIM simulation results were obtained to analyze the motion and flow characteristics of each hydraulic circuit system, which verified the rationality of the hydraulic system.