bluuebunny/crossref_metadata_2025 huggingface dataset:
Gravitational Faraday Rotation of gravitational waves by a Kerr black hole
Authors: Li Zhao , Qiao Jin , Zhao Wen , Er Xinzhong
Published: October 2022

Gravitational Faraday Rotation (GFR) is a frame-dragging effect induced by rotating massive objects, which is one of the important, yet studied characteristics of lensed gravitational waves (GWs). In this work, we calculate the GFR angle χ
g
of GWs in the weak deflection limit, assuming it is lensed by a Kerr black hole (BH). We find that the GFR effect changes the initial polarization state of the lensed GW. Compared with the Einstein deflection angle, the dominant term of the rotation angle χ
g
is a second-order correction to the polarization angle, which depends on the light-of-sight component of BH angular momentum. Such a rotation is tiny and degenerates with the initial polarization angle. In some critical cases, the GFR angle is close to the detection capability of the third-generation GW detector network, although the degeneracy has to be broken.
Advancing globular cluster constraints on the axion-photon coupling
Authors: Dolan Matthew J. , Hiskens Frederick J. , Volkas Raymond R.
Published: October 2022

We improve the current upper bound on the axion-photon coupling derived from stellar evolution using theR2parameter, the ratio of stellar populations on the Asymptotic Giant Branch to Horizontal Branch in Globular Clusters. We compare this with data from simulations using the stellar evolution codeMESAwhich include the effects of axion production. Particular attention is given to quantifying in detail the effects of uncertainties on theRandR2parameters due to the modelling of convective core boundaries. Using a semiconvective mixing scheme we constrain the axion-photon coupling to begaγγ< 0.47 × 10-10 GeV-1. This rules out new regions of QCD axion and axion-like particle parameter space. Complementary evidence from asteroseismology suggests that this could improve to as much asgaγγ< 0.34 × 10-10 GeV-1as the uncertainties surrounding mixing across convective boundaries are better understood.
Identification of centrifugal pump flow based on feature recognition
Authors: You YiLin , Chen Xiaonan , Bai Xi , Liang Caihua
Published: October 2022

The flow rate of water pumps is a crucial parameter for diagnosis, optimisation and renovation of transmission and distribution systems. To solve the problems of limited measurement conditions, inadequate consideration of operational wear and tear, and large deviations in the fitted flow curves when obtaining flow rates by direct measurement or characteristic curve fitting, this paper proposes a method for identification of centrifugal pump flow rates based on feature recognition. The method combines the unknown structural parameters of a centrifugal pump with three simple and easy-to-measure operating data: pump head, frequency and power, to obtain the pump characteristics and construct a model for identification of centrifugal pump flow. At the same time, the influence of measurement errors and wear and tear on the model’s accuracy is investigated. The results show that the maximum relative error of the pump operating flow obtained by the method is 2.27%, a slight deviation from the actual measured flow. The maximum relative error of flow rate is 2.7% when a maximum measurement error of ± 0.1%, 0.5% and ± (3%+5) for the required operational data, respectively, indicating that the method has a high resistance to interference. The method considers the different degrees of operating wear and tear of the pumps, saves on equipment input and enables fast and accurate identification of the flow rate of the pumps under different operating conditions.
Method of Extracting Shape Error Based on Wavelet Filtering
Authors: Ma Yuchuan , Gao Xuanyi , Xiong Jian , Zhang Zhijing
Published: October 2022

According to the experience in actual engineering, surface topography usually consists of three parts: shape error, waviness and roughness. The shape error message is usually more important and concerned in analysing and evaluating the performance of the work pieces in assembling. This paper proposes a method of shape error extraction based on wavelet filtering: first, a set of simulated data is generated by the experience in engineering, second, the process of wavelet filtering and shape error extraction is designed, then, the shape error from the simulated data is extracted according to the designed process and compared the results with the results obtained by traditional methods, finally further verification is carried out on a set of real measured data. For both of the simulated data or and the real measured data, the shape error extracted very well. The feasibility of the method is confirmed.
Intelligent Electrical Engineering Automation on Account of Particle Swarm Optimization (PSO) Algorithm
Authors: Li Zhiwei
Published: October 2022

Electrical engineering is closely related to people’s life. Many projects have proved that electrical engineering using PSO algorithm provides more convenient applications for people’s production and life, greatly improves people’s living standards, and makes people’s life and work more relaxed and valid. In many production fields, such as subway engineering, if advanced electrical engineering automation is adopted, the subway engineering can be carried out validly from start to finish, and the workload of workers can be greatly reduced. PSO algorithm further improves the automation performance of electrical engineering, and effectively breaks through the traditional electrical engineering operation mode, improve the operation efficiency. This text studies the concept and work flow of PSO algorithm, introduces the intelligent working principle and internal mechanism of electrical engineering. Data analysis, intelligent electrical engineering automation on account of PSO algorithm effectively improve the intelligent effect of electrical engineering automation.
A path smoothing scheme for micro-line tools using cubic B-spline fitting with dominant points
Authors: Hu Yifei , Jiang Xin , Huo Guanying , Su Cheng , Li Hexiong
Published: October 2022

To obtain higher order continuous tool path, a cubic B-spline curve fitting method is presented in this paper to process the linear tool path. First, a local cubic polynomial fitting with bidirectional scanning scheme is proposed to determine some initial dominant points. Based on these dominant points, the initial knot vector is generated by average method, and the initial B-spline is constructed. To constrain the fitting error, a Newton’s method based fitting error estimation scheme and a fitting error based dominant point insertion scheme are proposed to modify the B-spline. Simulation results prove that our method can compress data and smooth tool path. Compared with another existing curve fitting method, the number of control point has decreased by 9.43%, and the machining time has decreased by 94.45% compared with traditional point-to-point (P2P) motion.
Robot-assisted assessment of the effects of self-aligning mechanism on the wrist passive range of motion
Authors: Xu Dong , Zhang Xu , Xu Han , Li Yibin , Li Xiaolong , Zhou Qicai , Fu Jianming , Gu Xudong
Published: October 2022

Axis alignment between human and robot has been a research hotspot in wearable rehabilitation robots and has a significant effects on full natural ranges of motion (ROM) during robot-assisted training exercises. Self-alignment mechanism (SAM) has been extensively applied on the rehabilitation robots to adaptively compensate the axis misalignment between human anatomic and robot mechanical joints. However, the effects of the SAM on the wrist ROM have not been definitely assessed. In this study, we implemented a SAM on a wrist rehabilitation device (WReD II), and the SAM was specially designed to be locked or unlocked to achieve self-alignment function or not according to demands. To assess the effects of SAM on the wrist passive ROM of extension/flexion (E/F), passive training experiments involving 8 healthy participants were conducted by locking or unlocking the SAM respectively. Surface Electromyography (sEMG) was applied to monitor muscle activity during experiments. During the experiments, the wrist passive ROM were measured by applying the robot-assisted assessment technique. Preliminary results show that the means of the passive ROM have a maximum increase of 19.78° in the case with SAM unlocked when compared to the case with SAM locked. Statistical results indicated high test-retest reliability of the passive ROM measurements with intraclass correlation coefficient ICC (2,1) more than 0.82, and standard error of measurement (SEM) less than 3.2°. These findings suggest that the implement of SAM on the rehabilitation robots has great potentials due to its feasibility and reliability to obtain larger natural passive ROM.
Research on Active Disturbance Rejection Thrust Stability Control of Permanent Magnet Reluctance Linear Motor
Authors: Chen Gaoqi , Zhang Huixian
Published: October 2022

Permanent magnet reluctance linear motor (PMRLM) has high thrust density, simple and reliable structure due to the structure of permanent magnet and current double excitation. It is suitable for all kinds of large factories and logistics sorting centres. However, the existence of double salient pole structure and permanent magnet flux harmonic, the thrust pulsation of the motor is very large. In view of the above problems, the mathematical model of PMRLM is established, and the ADRC technology is proposed to be introduced into the thrust stability control. By building a simulation platform and comparing with the traditional PID control, the results show that the ADRC effectively reduces the thrust pulsation to a certain extent, and has good robustness and anti-interference.
Research and Simulation of a Synchronous Fieldbus Technology Based on OPNET
Authors: Wang Zhiqiang , Wang Rui , Fan Ping , Xun Panpan , Wang Zhe , Xue Shaohui
Published: October 2022

Synchronous fieldbus technology is based on the traditional CAN bus with the time division technology, so that communication nodes only send data in a characteristic time slice of a communication cycle. The method can eliminate the conflict between nodes and avoid the competition between nodes of the bus. In this paper, the node layer, LLC process layer and MAC process layer models of the synchronous fieldbus technology are established in the OPNET environment, and an experiment is designed to simulate the actual use scenario, and the method is verified. The result of the method is correct, the effect of it is intuitive, the simulation method of it is correct, and it can be used in synchronous fieldbus simulation research and engineering application.
Regional Stability of Switching Control Circuit Systems with Multiple Equilibria
Authors: Yang Shengxu
Published: October 2022

This paper investigates the stability of systems of multi-equilibrium switching circuits. For a first-order switching circuit system with two subsystems containing unique equilibria and different equilibria, we first establish a sufficient condition for the stability of the region of the multi-equilibrium first-order switching circuit system, and then complete the proof of its stability by means of a general solution of the system state. Secondly, for the second-order multi-equilibrium switching circuit system, the sufficient condition for the stability of the second-order multi-equilibrium switching circuit system is given, and the feasibility of the theorem is finally proved by drawing on existing research results and related sufficient conditions. The conclusions obtained show that the system of first- and second-order multiple equilibria switching circuits in the region is regionally stable after the corresponding switching paths.
Analysis of water cooling system for electric aircraft frequency conversion power supply device
Authors: Ma Song , Chen Ping , Fan Xinyue , Lv Dawei
Published: October 2022

Using an electric propulsion system instead of internal combustion engine power, electric aircraft have the advantages of energy conservation and environmental protection. This paper proposed an analysis method of the water cooling system for the frequency converter of an electric aircraft which aims at increasing the power density of the frequency converter. The turbulence of the cooling water influence heat dissipation, which is important in the calculation of fluent field. Based on fluent field calculation, the relationships between the flow quantity and temperature, the flow quantity and pressure, the flow velocity and temperature, and the flow velocity and pressure of the water cooling system are received, which guided the design of the water cooling system. Then the flow quantity is determined to be 0.8m3/h, the cross-section of the cooling water channel is determined to be 9.5mm×10mm, and the maximum temperature of the converter frequency is 67.27°C, which is verified by the experiment. The calculation results for the final water cooling system are within usage requirements which benefit future design.
Detection of Three-Phase Voltage Sag under Multiple Power Quality Disturbances
Authors: Wang Qing , Zhang Huaying , Yuan Tao , Han Song , Deng Tianbai , Tao Jun
Published: October 2022

Voltage sag is an unavoidable short-term power quality disturbance problem in the power system. Rapid and accurate detection of voltage sag characteristic quantities is the premise of dealing with the sag problem. Based on the principle of d-q transformation and ISOGI-QSG structure, this paper proposes a method for fast detection and identification of three-phase voltage sag. It describes the working principle of the improved SOGI in detail. In addition, the structure of three-phase voltage sag independent detection is analyzed, and a fast determination method for sag fault types is proposed. The advantages of this method compared with traditional three-phase voltage detection are verified by simulation comparison, and it still has good anti-interference ability and better dynamic performance under various power quality disturbances. Moreover, the detection speed can meet the time requirements of sensitive loads for dual power switching.
Parameter design method of grid-connected inverter microgrid system
Authors: Yang Liyong , Zhao Dongchu
Published: October 2022

LCL filter is widely used in three-phase voltage converters due to its superior high-frequency harmonic suppression ability. In this paper, aiming at the instability problem caused by the resonance peak of the impedance characteristics of the LCL filter third-order system, the relationship between the parameters of the filter inductance, damping resistance, and the harmonic suppression ability is deduced. The impedance analysis method is used to obtain the constraint conditions of the grid stability on the LCL parameters. Based on the stability criterion, a parameter design scheme of passive damping LCL filter is proposed. Finally, experiments are conducted on filters that conform to the proposed design method, and the simulation results verify the rationality and effectiveness of the design method.
Design and Optimization of Amplifying Mechanism in Gas-Liquid Thermoelectric Power Device
Authors: Huang Li , Shen Zhen-Jun
Published: October 2022

Aiming at the small output displacement of the gas-liquid temperature difference power device, a flexible hinge displacement amplification system was designed and optimized using the lever principle. The formula for calculating the magnification of the lever-type flexible hinge mechanism was derived by taking into account the offset of the flexible hinge's rotational center. Likewise, consider how the parameters of the mechanism affect the output performance of the amplifying mechanism. Combining SolidWorks and Workbench to improve the amplifying mechanism's parameters, find the best value for the parameters, and experimentally validate the optimized results. The research shows that the error between the experimental data and the finite element simulation value is 2.49%, which verifies the correctness of the simulation model. The design goals of high magnification of the mechanism and output after displacement amplification are realized.
Design and Simulation of Satellite Attitude Control Algorithm Based on PID
Authors: Shan Yihe , Xia Lurui , Li Sen
Published: October 2022

According to the tasks of mapping and reconnaissance, the satellite needs to adjust its attitude and keep its attitude stable when it is in orbit. Firstly, the kinematic model and dynamic model of satellite attitude are established.Then the digital simulation of satellite attitude control system is built based on the mathematical model of satellite attitude, in which the control modules use PID controller and fuzzy PID controller respectively. Finally, the steady-state performance and dynamic performance of the two controllers are compared and analyzed.The experimental results show that both fuzzy PID control and fuzzy PID control can be used as effective means of attitude control.Both of them have high precision, fast speed and good steady-state performance to achieve the desired attitude. Fuzzy PID control also has the ability of self-tuning controller parameters, which makes the control process smoother.
Design and validation of a wheel-rail adhesion simulator in PLS-Circulator
Authors: Chen Chao , Tian Chun , Huang Ting Xiang , Zhu Wen Liang
Published: October 2022

A 1:4 scaled test rig called 'PLS-Circulator' is introduced for wheel-rail contact research under large slip conditions, which is composed of two wheel assemblies, 2 m diameter ring track with sprinklers surrounded, gearbox and two servo motors. On this basis, a wheel-rail adhesion simulator was designed to generate and measure the wheel-rail contact force. The slip ratio is the specific value of two motor speeds, which brings convenience to precisely control. SIMPACK simulation results showed that the slip ratio converged to the target value after the initial time in consideration of gear meshing vibration. The validation of the adhesion recovery was carried out utilizing PLS-Circulator under large slip conditions. Experimental results showed that in both steady and dynamic slip ratio experiments the adhesion coefficient could increase up to 26% from a lower adhesion caused by wet wheel-rail interface at the vehicle velocity of 20 km/h.
Research on control strategy of Vienna rectifier based on sliding mode control
Authors: Wang Sizhong , Jia Wenchao , Li Lulu , Li Shuang , Yu Zonglai
Published: October 2022

The low harmonic content of the grid-side output power of the three-phase, three-level Vienna rectifiers makes them commonly used in hybrid AC-DC microgrids. However, the grid connected current performance of three-phase Vienna rectifier is highly dependent on the value of controller parameters. Unreasonable value often leads to grid side current distortion and poor system anti-interference. Firstly, the mathematical model of three-phase Vienna is established and analyzed, and a control strategy based on sliding mode variable structure control is designed to improve the dynamic and static performance of grid connected current, and the model is built and simulated in MATLAB simulation environment. The simulation results show that the control strategy designed in this paper can effectively ensure the dynamic and static performance of the output voltage and current of the three-phase Vienna rectifier, and has strong anti load disturbance ability.
Closing pre-strike duration of the circuit breaker during electrical life degradation
Authors: Peng Yanjun , Pan Ningbo , Zhou Xiong , Wang Lu , Chen Jianxi , Huang Yongqiang , Dong Hailiang
Published: October 2022

In order to better evaluate the electrical life state of circuit breaker, a 110kV SF6 circuit breaker was carried out for simulated ablation tests, and closing pre-strike duration was measured during ablation. The results show that with the progress of ablation, the pre-strike duration of closing process increases in the first, and then tends to saturation, while the whole curve presents a certain fluctuation. The experimental results have a positive effect on the evaluation of the electrical life state of the circuit breaker in operation.
Study on a theory and method of detonation control simulation
Authors: Zhao Jinqing , Sun Yong , Lu Guangzhao , Wang Xun , Wang Di , Zhang Shaopan , Cao Junqing , Wei Lan
Published: October 2022

Detonation control simulation is an important issue in the field of ammunition performance analysis. Extensive research has been carried out at home and abroad, this paper presents a theory and method of detonation control, including detonation control theory and method, initiation point calculation method, guidance error calculation, fuze trigger calculation, coordinate transformation of fuze trigger point start point, recursive calculation of fuze start delay and so on. The accurate starting of fuze and the simulation of ammunition detonation control are realized, combined with practical application, good results have been achieved.
Photovoltaic power prediction based on multi-layer fusion model
Authors: Qin Weiming , Guo Wenjing , Li Wenjing , Liu Yumin , Gao Liyuan , Zhang Wei , Lin Jingwen
Published: October 2022

Accurate forecasting of photovoltaic power output can provide technical guidance for smooth grid connection of photovoltaic power plants and avoid grid energy quality problems caused by large fluctuations in photovoltaic power. Therefore, it is very important to obtain more accurate photovoltaic energy forecast data. The traditional photovoltaic power forecasting model has the problems of low forecast accuracy and hysteresis.to further improve the prediction accuracy of pv power, this paper proposes a multi-layer fusion PV power prediction model based on dynamic modification of the weight parameters of each model. The model's benchmark algorithms include XGBoost, LigthGBM and ConvLSTM. In the case study, real photovoltaic station data were used to verify the simulation,The forecast results show that the model proposed in this paper has a better effect than any single model and has strong practicability.
Piecewise and Nonlinear Power Compensation Model for Gateway Meters in Substations
Authors: Deng Siyang , Chen Kaiming , Wang Yonggui , Huang Lvchao
Published: October 2022

In order to measure the electric energy and monitor the power quality in substations with accuracy, higher precisions are required for the gateway meters. Due to the wide dynamic range of the current and the nonlinearity of the compensation models, the calibration becomes complicated to guaranteeing the accuracy over the full range. For the purpose of decreasing the complexity of calibration, a piecewise and nonlinear compensation model is presented in this paper. With this model, all the values needed could be calibrated within two calibration points and the accuracy could achieve the requirements of precision over the full range. Results shows the efficiency of this method.
Microgrid Droop Control Based on Simulated Annealing Adaptive Particle Swarm Optimization
Authors: Liang Jiangyi , Zou Hairong
Published: October 2022

Droop control has been widely used and researched as a characteristic method to achieve current distribution. The traditional droop control has inherent limitations. With the development of various control algorithms, the sec-ondary control of the DC microgrid droop control is no longer limited to the use of classical deviation adjustment or the general compensation method of the associated parameters for compensation. An improved droop control method based on the optimal compensation method. Compared with the traditional particle swarm optimization, the adaptive particle swarm optimization (ASAPSO) algorithm based on simulated annealing is adopted, which enhances the ability of the particle swarm to improve the convergence speed and convergence accuracy. By improving the algorithm, the optimization results are fed back to the droop parameters in real time, so as to improve the optimization effect. The effectiveness and viability of the proposed control method are verified by simulation experiments with MATLAB/Simulink.
Comprehensive Evaluation of Power Quality Based on AHM-CRITIC Method
Authors: Xu Shuang-ting , Fang Xiao-ling , Lin Yan , Lan Jin-chen , Zhang Zhi-geng
Published: October 2022

In order to manage the level of power quality more effectively, a comprehensive evaluation method of power quality based on Attribute Hierarchy Model (AHM)- Criteria Importance Through Intercriteria Correlation (CRITIC) is proposed in this paper. Firstly, collect expert opinions and determine the subjective weight of each power quality index based on AHM method. Secondly, the power quality data of monitoring points are counted and processed based on CRITIC method, so as to obtain the objective weight of each index. Then, the comprehensive weight of each power quality index is determined based on the minimum discrimination information method. Finally, according to the standard grading and index comprehensive weight, the comprehensive power quality evaluation of each monitoring point is carried out. Through the analysis of practical examples, it is verified that the proposed method can comprehensively consider the subjective and objective factors and obtain more accurate and comprehensive power quality evaluation results.
PID control strategy of wind transmission chain based on particle swarm optimization
Authors: Fu Zhi Hao , Sun Yuan
Published: October 2022

Wind turbine transmission chain is the key component of wind turbine to bear various loads, and its working characteristics are an important basis for testing the stability, reliability and safety of wind turbine. Aiming at the transmission chain system, a load simulation technology for ground test system of 1.5MW wind turbine transmission chain was proposed. According to its performance and requirements, a hydraulic loading system with 6-dOF load was designed. Hydraulic loading system is designed according to wind load. Through the mechanism method to establish its mathematical model, particle swarm optimization algorithm is easy to fall into the local optimal solution, using quantum particle swarm optimization algorithm, through Matlab/Simulink load simulation of the hydraulic loading system, the results show that the hydraulic loading system has a good tracking and reproduction of wind load
Equivalent Impedance Modeling and Stability Analysis of MMC-HVDC with Wind Farm
Authors: Liu Min , Huang Peng , Sun Lixiang , Zhuo Guying
Published: October 2022

The risk of resonances may exist in the power electronic transmission systems composed of wind farm (WF) and the high-voltage direct-current system consisting of modular multilevel converter (MMC-HVDC). And the oscillation frequency will show coupling characteristics. The frequency dynamic interaction effect causes the WF interconnected with MMC-HVDC system exhibit multiple-input multiple-output (MIMO) characteristics. The stability determination of the system will become very difficult. Therefore, using frequency dynamic interaction effect as one of the constraints, this paper uses the harmonic state space (HHS) method to establish the two-dimensional impedance model of the wind farm side MMC(WFMMC) and the grid-side converter (GSC) of the wind farm, and further an accurate dimensionality reduction method is proposed. Finally, the results of the simulation system built based on MATLAB/Simulink verify the accuracy of the established impedance model and show that using the established model for stability analysis can obtain more accurate analysis results.
Performance Test and Cause Analysis of Girth Weld with Defects
Authors: Xu Yan , Wu Mingchang , Nie Xianghui , Feng Zhenjun , Li Liang , Yang Fengping
Published: October 2022

In this study, the performance test and defect anatomy analysis were carried out for a girth weld of the pipeline. The results of the girth weld tensile test, groove hammer break test and Vickers hardness test showed no obvious abnormality, and the impact toughness and bending test results were not ideal. In the conventional inspection process, it was found that there were tiny unfused girth welds at 6 o 'clock and 9 o 'clock positions, and the maximum direction size of defects on the wall thickness section was 1.57 mm. The defects at the position from 6 o 'clock to 7 o 'clock found by on-site X-ray detection were identified as the existing non-fusion defects by anatomical analysis, and should be considered as the root of incomplete welding defects that could not be completely eliminated during repair welding. The length and height of the defects are 9 mm and 1.38 mm.
Effect of Heat Treatment on the Oranization and Mechnical Properties of 7A09 Aluminnium Alloy
Authors: Qin Ming , Ling Liping , He Bing , Qin Wendong , Wu Lei
Published: October 2022

The 7A09 aluminum alloy was subjected to T6 heat treatment by means of microstructure analysis and mechanical property testing. The results show that the best solid solution treatment process of 7A09 aluminum alloy is 470°C*1 hr. The transverse tensile strength of 7A09 aluminum alloy reaches 555.9MPa, the elongation of 7A09 aluminum alloy reaches 13.5%, and the cloth hardness reaches 152.6HBW. Compared with the cast aluminum alloy, the tensile strength, elongation and hardness increase by 10.3%, 8% and 13.5% respectively, and the mechanical properties of 7A09 aluminum alloy are significantly improved. The mechanical properties of the alloy are significantly improved.
Performance of Li-ion battery with silicon nanowire in anode
Authors: Li Wenhan
Published: October 2022

Li-ion batteries are extensively used in electronic devices, cell phones, new energy vehicle batteries, and other sectors, and they have a lot of promise in electric cars and other domains. With the development of the times, batteries with carbon as anode material can no longer meet the demand of electric vehicles and other fields for battery energy density. Silicon, one of the most potential anode materials, demonstrates extremely high theoretical battery energy density. In the past few years, research on silicon nanostructures, especially silicon nanowires, has effectively solved the problem of volume change of Li alloying with Si, and significantly improved the life and charge-discharge rates of anodes. Moreover, the composite of silicon nanowires with other materials has become one of the most interesting research directions. This paper reviews several silicon nanowires grown in different preparation methods and their impacts on the performance of lithium-ion batteries as anode materials. Two kinds of silicon nanowire composite with other materials as anode of lithium-ion battery are also introduced.
Investigation on the influence of the structural characteristics of particle dampers on its damping performance
Authors: Guo Yangyang , Ji Feilong
Published: October 2022

Under the condition of vertical harmonic excitation, the influence of two structural characteristics of the damping rod and the inner wall on the damping characteristics of the damper is studied. The force signal and acceleration signal of the damper under different excitation conditions are measured through experiments.The damping characteristics such as effective mass, loss power and loss factor of the damper are analyzed by the steady-state energy flow method. The experiment results indicate that, on the basis of ordinary particle dampers, adding damping rods can intensify the friction and extrusion of particles and rods, thereby enhancing the energy dissipation performance. By pasting rubber material on the inner wall of the damper, the soft inner wall can consume the acoustic energy during collision, enhance the energy consumption during collision, and improve the damping effect.
Solutions for elastic moduli of three-phase composite with random distribution of coated-ellipse inclusions
Authors: Nguyen Van-Luat
Published: October 2022

Some solutions in this work are developed to estimate the elastic moduli of three-phase isotropic composite with random coated-ellipse inclusion in the matrix. Solutions to the macro-elastic moduli of materials in two-dimensional space using approximation and numerical methods including equivalent-inclusion (EI), polarization approximation (PA), differential approximations (DA), and fast Fourier transformation (FFT). In which, there is a combination of those methods to give approximations such as EI-PA, EI-DA, FFT-EI. The construction algebraic expressions can be directly applied to the random coated-ellipse model, in special cases it can be used for circular aggregate particles. The numerical solutions using FFT analysis will be compared with EI-PA, EI-DA, and Hashin–Shtrikman’s bounds. From this, it is possible to indicate the best solution that engineers can use to determine the elastic modulus of the coated-ellipse model.
Invariant subspaces of the generalized backward shift operator and rational functions
Authors: Ivanova O. , Melikhov S. , Melikhov Yu.
Published: October 2022

The paper is devoted to a complete characterization of proper closed invariant subspaces of the generalized backward shift operator (Pommiez operator) in the Fréchet space of all holomorphic functions in a simply connected domain

Ω
∋
0

\Omega \ni 0

in the complex plane. In the case when the function that generates this operator does not have zeros in

Ω
\Omega

, all such subspaces are finite-dimensional. If in addition

Ω
\Omega

coincides with the entire complex plane, then the generalized backward shift operator under consideration is unicellular. If this function has zeros in

Ω
\Omega

, then the above family of invariant subspaces splits into two classes: the first consists of finite-dimensional subspaces, and the second of infinite-dimensional ones.
Supercharacters for parabolic contractions of finite groups of 𝐴,𝐵,𝐶,𝐷 Lie types
Authors: Panov A.
Published: October 2022

Supercharacter theories are constructed for the finite groups obtained by parabolic contraction from simple groups of

A
,
B
,
C
,
D

A,B,C,D

Lie types. Supercharacters and superclasses are classified in terms of rook placements in root systems.
Are We Undercounting the True Burden of Mortality Related to Suicide, Alcohol Use, or Drug Use? An Analysis Using Death Certificate Data From Colorado Veterans
Authors: Spark Talia L , Adams Rachel Sayko , Hoffmire Claire A , Forster Jeri E , Brenner Lisa A
Published: October 2022

Knowledge regarding deaths due to suicide or alcohol- or drug-related causes may be limited by inconsistent and/or restrictive case definitions, resulting in concerns regarding validity of findings and underestimates of burden. In this proof-of-concept study, we assessed varying case definitions (suicide, alcohol-related, and drug-related mortality using underlying-cause-of-death (UCOD) versus multiple-cause-of-death (MCOD) International Classification of Diseases, Tenth Revision (ICD-10) codes) on the basis of counts and rates among Colorado veterans who died (2009–2020). Suicide, alcohol-related, or drug-related ICD-10 codes were identified, and 2 case definitions were compared: UCOD (qualifying ICD-10 code listed as the UCOD) and MCOD (qualifying ICD-10 code in any cause-of-death field). Of 109,314 decedents, the number of deaths and the age-adjusted mortality rate (per 100,000 persons) significantly increased when MCOD codes were included: n = 4,930 (110.3 deaths/100,000 persons) for UCOD versus n = 6,954 (138.4 deaths/100,000 persons) for MCOD. While rates of suicide mortality did not change, rates of alcohol-related mortality doubled with the more inclusive case definition: 1,752 (27.3 deaths/100,000 persons) for UCOD versus 3,847 (59.8 deaths/100,000 persons) for MCOD. Alcohol-use disorder codes accounted for 71% of additional alcohol-related deaths captured with the MCOD definition. Studies that rely on UCOD codes may be underestimating the burden of deaths, especially alcohol-related deaths. Increased effort is required to reevaluate current classifications of deaths associated with suicide, alcohol use, or drug use.
Convex hull as diagnostic tool in single-molecule localization microscopy
Authors: Ebert Vincent , Eiring Patrick , Helmerich Dominic A , Seifert Rick , Sauer Markus , Doose Sören
Published: October 2022

Motivation

Single-molecule localization microscopy resolves individual fluorophores or fluorescence-labeled biomolecules. Data are provided as a set of localizations that distribute normally around the true fluorophore position with a variance determined by the localization precision. Characterizing the spatial fluorophore distribution to differentiate between resolution-limited localization clusters, which resemble individual biomolecules, and extended structures, which represent aggregated molecular complexes, is a common challenge.

Results

We demonstrate the use of the convex hull and related hull properties of localization clusters for diagnostic purposes, as a parameter for cluster selection or as a tool to determine localization precision.

Availability and implementation

https://github.com/super-resolution/Ebert-et-al-2022-supplement.

Supplementary information

Supplementary data are available at Bioinformatics online.
Population-based assessment of nusinersen efficacy in children with spinal muscular atrophy: a 3-year follow-up study
Authors: Scheijmans Féline E V , Cuppen Inge , van Eijk Ruben P A , Wijngaarde Camiel A , Schoenmakers Marja A G C , van der Woude Danny R , Bartels Bart , Veldhoen Esther S , Oude Lansink Irene L B , Groen Ewout J N , Asselman Fay-Lynn , Wadman Renske I , van der Pol W Ludo
Published: October 2022

Nusinersen (Spinraza®) improves survival of infants with hereditary proximal spinal muscular atrophy and motor function in children up to 12 years. Population-based assessments of treatment efficacy are limited and confined to select cohorts of patients. We performed a nationwide, population-based, single-centre cohort study in children with spinal muscular atrophy younger than 9.5 years at start of treatment in line with reimbursement criteria in the Netherlands. We assessed age-relevant motor function scores, the need for tube feeding, hours of ventilatory support and documented adverse events. We used linear mixed modelling to assess treatment effects. We compared motor function during treatment with natural history data and to individual trajectories of muscle strength and motor function before the start of treatment. We included 71 out of 72 Dutch children who were treated (median age 54 months; range 0–117) and followed them for a median of 38 months (range 5–52). We observed improvement of motor function in 72% and stabilization in another 18% of the symptomatic children, which differed from the natural disease course in a matched cohort of which we had previously collected natural history data. Longitudinal analysis showed that motor function improved up to a median of 24 months (range 12–30) of treatment after which it stabilized. Shorter disease duration at start of treatment resulted in better treatment efficacy (P < 0.01). Sixteen children (23%) achieved new motor milestones. Bulbar and respiratory function did not improve significantly during treatment. In 15 patients from whom treatment-naïve data were available, the pre-treatment trajectory of motor function decline changed to stabilization or improvement after the start of treatment. We documented 82 adverse events after 934 injections (9%) in 45 patients. None of the adverse events led to treatment discontinuation. Intrathecal nusinersen treatment is safe and improves or stabilizes motor function in 90% of young children with spinal muscular atrophy types 1c–3a. We did not observe improvement of respiratory and bulbar functions.
Somatosensory gating is related to behavioral and verbal outcomes in children with mild-to-severe hearing loss
Authors: Heinrichs-Graham Elizabeth , Walker Elizabeth A , Lee Wai Hon , Benavente Amanda A , McCreery Ryan W
Published: October 2022

Sensory gating is a process by which the brain filters out redundant information to preserve neural resources for behaviorally relevant stimuli. Although studies have shown alterations in auditory and visual processing in children who are hard-of-hearing (CHH) relative to children with normal hearing (CNH), it is unclear whether these alterations extend to the somatosensory domain, and how aberrations in sensory processing affect sensory gating. In this study, CHH and CNH were presented with a paired-pulse median nerve stimulation during magnetoencephalography. Stimulus-related gamma neural activity was imaged and virtual time series from peak somatosensory responses were extracted. We found significant effects of both stimulus and group, as well as a significant group-by-stimulus interaction. CHH showed a larger response to stimulation overall, as well as greater differences in gamma power from the first to the second stimulus. However, when looking at the ratio rather than the absolute difference in power, CHH showed comparable gating to CNH. In addition, smaller gating ratios were correlated with better classroom behavior and verbal ability in CHH, but not CNH. Taken together, these data underscore the importance of considering how CHH experience their multisensory environment when interpreting outcomes and designing interventions.
Impact of public restrictive measures on hypertension during the COVID-19 pandemic: existing evidence and long-term implications
Authors: Karagiannidis Artemios G , Theodorakopoulou Marieta P , Ferro Charles J , Ortiz Alberto , Soler Maria Jose , Halimi Jean-Michel , Januszewicz Andrzej , Persu Alexandre , Kreutz Reinhold , Sarafidis Pantelis
Published: October 2022

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that was first identified in December 2019 and emerged into an ongoing global pandemic. Both the pandemic itself and the associated public restrictive measures of social mobility established with different intensity over different periods in various countries have significantly affected the everyday activities and lifestyles of people all over the world. The impact of lockdown and quarantine measures on hypertension incidence and blood pressure (BP) control is an important topic that requires further investigation. The aim of this review is: a) to present the current evidence regarding the actual effects of public restrictive measures on BP levels and control, originating primarily from studies investigating the impact of public restrictive measures on BP control with the use of various BP phenotypes; b) to summarize the possible pandemic-related effects of factors known to affect BP levels, including both traditional (e.g. dietary habits including alcohol and sodium intake, body weight, smoking and physical activity) and non-traditional (e.g. sleep patterns, air pollution, environmental noise, delayed diagnosis and medication adherence) ones.
Depression is associated with frailty and lower quality of life in haemodialysis recipients, but not with mortality or hospitalization
Authors: Anderson Benjamin M , Qasim Muhammad , Correa Gonzalo , Evison Felicity , Gallier Suzy , Ferro Charles J , Jackson Thomas A , Sharif Adnan
Published: October 2022

Background

Frailty and depression are highly prevalent in haemodialysis recipients, exhibit a reciprocal relationship, and are associated with increased mortality and hospitalization, and lower quality of life. Despite this, there has been little exploration of the relationship between depression and frailty upon patient outcomes. We aimed to explore the relationship between depression and frailty, and their associations with mortality, hospitalization and quality of life.

Methods

We performed a prospective cohort study of prevalent haemodialysis recipients linked to national datasets for outcomes including mortality and hospitalization. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), frailty using the Clinical Frailty Scale (CFS) and quality of life using the EuroQol 5-Dimension (EQ-5D) Summary Index.

Results

A total of 485 prevalent haemodialysis recipients were recruited, with 111 deaths and 1241 hospitalizations during follow-up. CFS was independently associated with mortality [hazard ratio (HR) 1.31; 95% confidence interval (CI) 1.08, 1.59; P = .006], hospitalization [incidence rate ratio (IRR) 1.13; 95% CI 1.03, 1.25; P = .010] and lower quality of life (Coef. −0.401; 95% CI −0.511, −0.292; P < .001). PHQ-9 score was independently associated with lower quality of life (Coef. −0.042; 95% CI −0.063, −0.021; P < .001), but not mortality (HR 1.00; 95% CI 0.96, 1.04; P = .901) or hospitalization (IRR 0.99; 95% CI 0.97, 1.01; P = .351). In an adjusted model including CFS, moderate depression was associated with reduced hospitalization (IRR 0.72; 95% CI 0.56, 0.93; P = .013).

Conclusions

With the addition of frailty, depression was associated with lower hospital admissions, but poorer quality of life. The relationship between frailty and depression, and their influence on outcomes is complex, requiring further study.
Two presentations of acute coronary syndrome with progression of giant right coronary artery aneurysm; a case report
Authors: van Vugt Stijn P G , Tan M Erwin S H , Habib Najibullah
Published: October 2022

Background

Giant coronary aneurysms are a rare finding on coronary angiography. Given its very low prevalence, little is known about optimal management of this coronary pathology.

Case summary

In this case report, we review the two presentations of a patient with acute coronary syndrome during a 6-year period. With regard to the second presentation, we review the investigations that demonstrate the progression of a coronary aneurysm in the right coronary artery as well as the Heart Team evaluations that resulted in surgical treatment of the coronary aneurysm.

Discussion

Following perspectives on prevalence and risk factors, we emphasize upon the available data with regard to interventional options in coronary aneurysms and describe the considerations with regard to interventional treatment in patients with giant coronary aneurysms. Finally, we discuss the available literature with regard to antithrombotic regimens in patients with coronary aneurysms.
Infective endocarditis of a left atrial appendage closure device: a case report and literature review
Authors: Al-Terki Hani , Mügge Andreas , Gotzmann Michael
Published: October 2022

Background

Due to advances in interventional cardiology in recent years, more and more patients are currently receiving cardiac devices, with a subsequent increase in the number of patients with device-associated endocarditis. Device-associated endocarditis is a life-threatening disease with special diagnostic and therapeutic challenges. Interventional devices for left atrial appendage (LAA) closure have been available for several years. However, there have been very few case reports of LAA closure device–associated endocarditis.

Case summary

An 83-year-old woman presented with fever and fatigue. She had a history of permanent atrial fibrillation and recurrent bleeding on oral anticoagulation. Consequently, the patient underwent interventional LAA closure ∼20 months earlier. Blood cultures grew Staphylococcus aureus. Transoesophageal echocardiography revealed an LAA closure device–associated mobile, echo-dense mass that was consistent with infectious vegetation in this clinical context. Intravenous antibiotic therapy was started, and our heart team recommended complete removal of the device, which the patient refused. The patient subsequently died as a result of progressive endocarditis and multiple pre-existing co-morbidities.

Discussion

Left atrial appendage occlusion device–associated endocarditis has rarely been reported. Due to the increase in LAA closure device implantation, device-associated endocarditis is expected to increase in the future. Transoesophageal echocardiography is required for correct diagnosis. Our case report suggests that an infection can occur long after implantation.