bluuebunny/crossref_metadata_2025 huggingface dataset:
Full-scale simulations of ‘In-Air Capturing’ return mode for winged reusable launch vehicles
Authors: Singh Sunayna , Sippel Martin , Stappert Sven
Published: June 2023

The recent success of reusable launchers has become a driving force for sustainable launch technologies. An innovative approach proposed by DLR, involves winged rocket stages captured mid air and towed back to the launch site by an aircraft. This recovery concept known as ‘In-Air Capturing (IAC)’, shows potential for substantial cost reduction, when compared to existing return modes. In the light of the Horizon 2020 project FALCon, full-scale simulations and sub-scale flight testing were carried out for further development of the technology. The paper summarizes the full-scale studies performed within FALCon. The full-scale test cases are introduced and the simulation framework for analysis of trajectories is presented. Then, the IAC maneuver is analyzed through trajectory simulations. Major external disturbances coming from the wake of the aircraft and flexibility of the rope connecting the rocket stage to the aircraft (after capture) are also addressed.
Composite Observer-based Finite-time Command Filtered Adaptive Control for Full-state Constraints Nonlinear Systems
Authors: Han Chaojie , Li Chunlei , Song Xiaona
Published: June 2023

In this paper, we look at a type of strict-feedback nonlinear systems that have neural adaptive finite-time command filtered control and full-state constraints. To begin with, indeterminate nonlinear functions are estimated using the NN. The system’s capacity to detect unmeasurable states and disturbances is done while using a composite observer, which significantly boosts the system’s anti-interference performance. Next, the issue of “complex explosion” that arose in the backstepping technique is resolved by adding a modified fractional-order filter. In order to address the full-state constraint issues, the BLF is also introduced. An adaptive finite-time tracking controller is created using Lyapunov’s theory analysis to make sure that all signals are confined to the finite time period. Lastly, a simulation study is conducted to evaluate the performance of the suggested control strategy.
High precision improved double-ended travelling wave ranging technology for offshore DC cables
Authors: Huang Haidong , Wang Ye , Ren Xuchao , Cui Yu , Li Peng
Published: June 2023

Aiming at the problem of fault location for offshore DC cables, this paper analyses the reasons why the double-ended method is more accurate than the single-ended method in DC transmission lines. We point out that the error in fault location on DC cables using the double-ended method mainly comes from the fact that the difference in wave speed between different segments is ignored. Therefore, based on the traditional double-ended method, this paper proposes an improved double-ended traveling wave ranging method which considers the difference in wave velocity and the actual situation of offshore cables connected in sections using flexible joint technology.
Differential rectification technique in a three-phase coil based angle sensor
Authors: Yang Jun
Published: June 2023

A technique of differential rectification is proposed for three-phase coil based inductive angle sensors so that the amplitude difference between any two of the amplitudes of three-phase coils is output for further signal processing. A 3-to-6 multiplexer, a low pass filter, and a 6-to-2 multiplexer are designed for the proposed technique, which is used for differential rectification, turning rectified signals into DC levels, and transmitting DC levels to the output of differential rectifiers, respectively. This differential rectification could suppress 3rd harmonic noise and common-mode noise, in order to improve the accuracy of angle calculation. The circuit of the proposed differential rectifier is given and simulation results shown in this manuscript verify the proposed circuit is feasible for three-phase coil based inductive angle sensors.
Linkage Selection Strategy Based on Attractor Profit Prediction in Heterogeneous Vehicle Network
Authors: Shen Yujie , Zhu Ziyao , Di Chenqi , Liu Xinyi
Published: June 2023

With the continuous development of wireless network technology, heterogeneous wireless networks with multiple network fusions and overlapping coverage have been formed. In the process of vehicles passing through different types of networks with different coverage areas at high speed, there are frequent and inefficient network switching behaviors. Aiming at this situation, a linkage selection strategy based on attractor profit prediction is proposed in a heterogeneous vehicle network. By analyzing the correlation between the wireless network transmission rate and the vehicle position, the location of the attractor update was found to reduce the transmission loss caused by network switching delay. Considering the vehicle speed and the access time of the base station, the transmission amount that the vehicle network can provide is calculated, the attractor is updated, and the network selection is made according to the state of the attractor. Compared with multi-attribute decision making, the linkage selection strategy based on attractor profit prediction can effectively improve the transmission volume of the Internet of vehicles. Through the simulation analysis, the transmission volume of the Internet of vehicles network increases by 14.07%.
Comparison of Active Full Compensation Control Algorithms for Single-phase Grounding Residual Current in Distribution Networks
Authors: Chen Hongyu , Hu Lining , Wang Han , Jia Yajun , Xi Dongmin
Published: June 2023

Current method and voltage method are two full compensation arc suppression control algorithms commonly used for single-phase grounding faults in the distribution network. The current method has a good compensation effect under small transition resistance, while the voltage method has a good compensation effect under large transition resistance. The existing research focuses on the control principle and implementation method of the current method and voltage method, but there is less research on the applicable boundary and comparative analysis of the control effect of these two methods. In view of this, this paper deduces the residual current full compensation theory of distribution network single-phase ground fault, introduces the control principles and implementation methods of the current method and voltage method respectively, establishes two evaluation indexes of residual current compensation accuracy and residual current compensation time, and conducts simulation and comparative research on the control effects of the two methods under different transition resistance and fault location. The results show that the dividing range of transition resistance applicable to the two methods is about 250 Ω–500 Ω. Within the dividing range, the compensation effect and control time of the two methods are equivalent. The current method surpasses the voltage method in compensation effect and control time below the dividing range, while the voltage method is superior to the current method in compensation effect and control time above the dividing range.
TMR sensor current measurement technology for overhead lines
Authors: Wu Xiangjun , Zeng Xiangjun
Published: June 2023

In order to meet the needs of TMR current sensors for overhead line high precision current measurement, a neighboring conductor interference magnetic field error elimination algorithm is proposed. Based on the Biot-Savard law, through the establishment of an interference magnetic field environment mathematical model, the accuracy of the error elimination algorithm is verified in maxwell simulation software. The simulation results show that under the working frequency current, the adjacent wire interference magnetic field elimination algorithm can reduce the error from 14% to less than 1%, and under the lightning wave environment, the error is reduced from 19% to less than 1%. This proves that the proposed algorithm is effective in reducing the measurement error caused by the interference magnetic field of the adjacent conductor.
Comparative Study on Modulation Modes of UWB communication
Authors: Yao Haoyuan , Huang Huijun , Fang Jinyong
Published: June 2023

Ultra wideband (UWB) communication technology is a communication technology that uses a very short time scale to transmit information. It has the advantages of a high transmission rate, low power consumption, and good privacy. In this paper, the basic principle of UWB technology is briefly described, several common UWB technologies are emphatically expounded, and the characteristics of each technology and their advantages and disadvantages are compared. At the same time, this article focuses on the difference between IR-UWB and DS-UWB
PID control of evaporation temperature control system based on fuzzy RBF neural network
Authors: Wang Jian
Published: June 2023

In this thesis, a fuzzy RBF neural network PID (RBFfnn-pid) control method is designed for temperature deviation concerning the steam curing temperature control system in the steam curing kettle of the aerated concrete block production line. The temperature control system (TCS) models of steam curing are established respectively under the control of fuzzy PID and RBFfnn-pid. Then, the control effect is analyzed by simulation in different situations. The results show that, under this condition of step signal inputting, the RBFfnn-pid control method shortens the rising time by 160 s and reduces the overshoot by 8% compared with the fuzzy PID controlling means. When the system is in a stable state, then the interference signal is added, which in contrast to the controlling means of fuzzy PID, the time for adjusting the RBFfnn-pid control to the set value is shortened by 70 seconds and there is no overshoot. The RBFfnn-pid control method enables the controlling parameters of the steaming temperature control system to be adjusted to the optimum quickly and iteratively, which improves the temperature control accuracy.
Causes and Solutions for the Mal-operation of Differential Pressure Protection of Substation
Authors: Liu Kunpeng , Yang Shaobing
Published: June 2023

The capacitor compensation circuit of the traction substation is affected by high-harmonics and the differential voltage protection is frequently mal-operation, which causes serious disturbance to the railroad transportation order. In this paper, the effect of parasitic inductance of capacitor banks and the parameter characteristics under high harmonics are analyzed by establishing the high-frequency circuit structure of capacitor banks. Then, a fitting formula describing the differential voltage is established based on the measured data to describe the frequency variation characteristics of the differential voltage value. Finally, a solution to the problem of differential voltage protection mal-operation of capacitor banks is discussed, a Resistance-Capacitance filter circuit is designed, and the effectiveness is verified by simulation.
Three-mode switching control Strategy based on Two-Switch Buck-Boost converter
Authors: Fang Ziwen , Yang Ziwei , Zhao Jiawei , Ye Chuangxin , Yang Yahong , He Xiaobin
Published: June 2023

The Two-Switch Buck-Boost (TSBB) converter can adjust a wide voltage range and is widely applied in the field of aerospace power supply. According to the energy relationship among the output power of the solar array, battery, and load, the converter can operate under three different modes. To solve the problem that the input voltage is clamped in the process of battery charging and the maximum power point tracking (MPPT) of the solar array is affected, a smooth switching control strategy between three modes is proposed in this paper. The operating mode of the current converter is determined by the variation of the current integral on the output capacitor, and it is used as the condition for the converter to exit the pass-through (PT) mode. In this way, the fast and stable switching between modes can be realized, and the dynamic response of the converter can be effectively improved. In addition, in order to avoid the input voltage disturbance affecting the output characteristics, this paper proposes a closed-loop control design based on input voltage feedforward control. Plecs simulation results show that the proposed loop control strategy has good stability and reliability.
Fault diagnosis of the transformer based on QPSO-SVM
Authors: Zhao Zhenxi , Guo Yufu , Xu Ao , Wang Guan , Huang Dapeng , Yang Biao
Published: June 2023

In view of the shortcomings of traditional dissolved gas analysis technology low diagnostic veracity and low intelligence, this paper proposes to use QPSO to optimize the nuclear argument in the support vector machine (SVM), and on this basis, dissolved gas analysis (DGA) technology is used to diagnosis transformer faults. Firstly, the transformer data is preprocessed by DGA technology, and the processed data is used as the input amount of fault characteristics. Secondly, for the optimization of core parameters in SVM, the QPSO algorithm is combined with fault data for training and acquisition. Finally, five kinds of feature inputs are added to the model for training, and the trained multi-classification correlation vector machine is used to diagnose the test data. After case studies and comparative experimental analysis, the diagnostic accuracy of this method is as high as 94.74%, and relatively with SVM, PSO-SVM, and RVM methods, the accuracy is increased by 5.11%, 2.12%, and 2.12%, respectively.
The Validation of The Weak Coupling Assumption in Transmission Line Equations of Coaxial Cables
Authors: Ni Huiyang , Zhang Weidong , Dong Zhiwei
Published: June 2023

The weak coupling assumption is frequently applied when solving coaxial shielded cable problems using transmission line equations. However, there are never enough justifications or no explicit indication of valid conditions. The purpose of this study is to provide the basis that supports the weak coupling assumption and a concise method to determine under what conditions the assumption holds. First, this paper summarizes the process of solving the shielded cable problem for different coupling methods. Further, this paper explores the conditions that must be met for the assumption by contrasting the weak coupling result with the numerical exact result. By comparing the weak-coupled model and the exact model under the electric short range, the ratio curve is obtained that can intuitively judge the weak coupling assumption validity. Then the coupling factors are proposed. And two examples are used as comparisons to validate. The ratio curves and coupling factors Kmin for determining the extent and degree of validity of the WCA are proposed, and validity is proved by examples.
Robustness Enhanced Predictive Control for Dual Three Phase PMSM with Duty Ratio Modulation and Parameter-Free Solution
Authors: Sun Jinyu , Cui Jia , Ma Shiwei
Published: June 2023

The classical model predictive control not only relies on the motor model but also is sensitive to the system parameters. To improve the robustness of the model predictive control system, this article proposes a parameter-free predictive control for a dual three-phase PMSM with duty ratio modulation. First, the free-model theory is employed to reconstruct the prediction model of the motor, of which no parameters are needed. So, the problem of parameter mismatch between the motor and the inverter can be handled, and enhance the robustness of the system as well. Moreover, the ultra-local model is optimized with the forgetting factor recursive least-squares algorithm to improve the identification accuracy of the estimated value. Finally, the deadbeat duty ratio modulation solution is introduced to further improve operational performance while ensuring the robustness of the system. Simulation and experiment verify the feasibility and effectiveness of the proposed algorithm.
Fault branch determination method based on the amplitude information of the first wave head of the initial traveling wave of the fault
Authors: Sun Shihang , Zhou Duyao , Liu Xiaohan , Yu Kun
Published: June 2023

In order to solve the difficult problem of fault branch determination in multi-branch distribution networks, the transmission characteristics of fault traveling waves in the distribution line are analyzed. The variation law of fault traveling wave amplitude with fault distance and frequency is deduced theoretically, and the reasons for the difficult determination of fault branch in the distribution line are revealed. A fault branch determination method based on the energy spectral density of the amplitude of the first wave head of the fault initial traveling wave is proposed. The reference node and the reference end of distribution networks are defined. The ratio of the intrinsic amplitude matrix to the real fault matrix before offline is calculated. The fault branch determination matrix is established to realize the reliable determination of the fault branch. PSCAD is used to build a 10 kV multi-dominant network model to simulate various fault conditions to verify the fault branch determination method. The simulation results show that the method can effectively identify the fault branch and has strong reliability.
Facile coating strategy of Si/C composite anode for high-performance lithium-ion battery
Authors: Zhang Yingchuan , Han Yongkang , Lei Yike , Ni Jie , Xiao Qiangfeng
Published: June 2023

Attributed to its high capacity by alloying with lithium, silicon is considered to be new generation of anodes that can replace graphite and receives much attention. Alleviating the electrode failure caused by volume expansion during lithiation and shrink during delihiation in silicon anodes plays a pivotal role in promoting the industrial application of silicon anodes. In this article, we proposed a facile carbon coating strategy on the surface of silicon nanospheres to buffer the stress during charge and discharge. By controlling the low molecular weight, an ethanol-soluble phenolic resin was synthesized and further self-assembled on the surface of silicon nanoparticles to form the precursor. Uniform Si/C composites were fabricated via pyrolysis. Diffraction of x-rays confirmed that the silicon retained the pristine crystalline structure. Scanning electron microscopy revealed a homogeneous wrap of the amorphous carbon layer on the superficies of the silicon. The galvanostatic charge-discharge test proved the excellent durability of Si/C anodes. Undergoing 50 cycles of galvanostatic lithiation/delithiation at 0.2C, the retention capacity was 96%, as high as 800 mAh/g. This facile but efficient strategy is compatible with large-scale production and improves the feasibility of the practical application of silicon-based anodes.
Dynamics Model Construction and Characteristic Analysis of Heat Pipe Nuclear Reactor in Thermal State
Authors: Yin Shaoxuan , Yu Ren , Mao Wei , Song Jian , Song Xiaoseng
Published: June 2023

In order to facilitate the power control method design of heat pipe nuclear reactor and avoid the high complexity of reactor core modelling, the paper adopts the lumped parameter method to build the thermal state dynamic model of heat pipe reactor. Firstly, the equivalence of the core structure and heat transfer process of the “MegaPower” heat pipe nuclear reactor is carried out to describe a single heat pipe in a hexagonal block. The complex heat transfer process in reactor core is simplified into a two-zone heat transfer model with only fuel and monolith. And the equivalent thermal resistance is used to describe the heat conduction process within gas gap and heat pipe. Then, the reactor core nuclear dynamic model is established using the neutron dynamics equation of point-reactor. Based on the principle of heat balance, the thermal dynamics models of fuel, gas gap, monolith and heat pipe are established respectively, so as to form the state equations of heat generation and heat transfer process in reactor core. Finally, the dynamic characteristics of the reactor with the reactivity disturbance without external control are simulated and analysed. The results show that the heat pipe reactor has a certain self-stability with reactivity disturbance, but the stability time is long, and the power fluctuation is large.
Effect of Reynolds number and frequency on heat transfer performance of a heat exchange tube under three-dimensional periodic oscillation
Authors: Ji Weihao , Tao Hanzhong , Li Yannan
Published: June 2023

To explore offshore conditions’ influence on the heat transfer capacity of heat exchangers, a numerical model of a heat exchanger tube under three-dimensional periodic oscillation was realized by adding UDF to commercial software. Meanwhile, the influence of Reynolds number and frequency on the heat exchange tube’s heat transfer capacity was inquired. Through discussion, it is found that the three-dimensional oscillation can enhance heat transfer performance at relatively low frequencies under any Reynolds number. The overall heat transfer enhancement decreases as the Reynolds number increases.
Study on anode single-phase flow pressure drop law of proton exchange membrane fuel cell
Authors: Qin Hao , Chen Huicui , Zhang Tong
Published: June 2023

This article briefly describes the research status of water flooding and pressure drop (PD) of the fuel cell. Then, a mathematical model of the single-phase flow PD of the fuel cell anode is established using hydrodynamics theory and referring to existing research. Then, the three-dimensional fuel cell model is established with Gambit software, and the grid is divided. Then, the numerical simulation of the single-phase flow of the fuel cell is carried out with Fluent software. Through the analysis of the simulation data, the relationship between the fuel cell anode pressure drops and some main influencing factors under steady-state conditions is explored, and the fuel cell anode’s single-phase flow pressure drop model is preliminarily verified. Anodes are highly sensitive to water flooding. The study of the single-phase flow PD law has a good contrast effect on the abnormal pressure drop during water flooding of fuel cells, which can be used to diagnose water flooding.
Fault Location of Power Battery System Based on Directed Graph Model
Authors: Zhang Weiliang , Jiang Lu
Published: June 2023

As the core part of the electric ship, the power battery system is the fault-prone area of the whole ship due to the harsh working environment and complex structure. This paper uses the method based on the directed graph model to build the directed graph model of the ship’s power battery system with the module as the basic unit to achieve the fault location of the ship’s power battery system at the module level and carries out simulation experiments to prove the feasibility of the scheme.
Calculation of Life Cycle Carbon Emissions of Residential Buildings
Authors: Yao Qingzhen , Yin Zimin , Wang Junmei , Li Jianlong , Shao Liangshan
Published: June 2023

The life cycle of a residential structure is separated into three stages: materialization, usage, and demolition, according to the life cycle theory of residential buildings. Materialization, use, and demolition computation models are built based on the features of residential building life cycle carbon emissions. The model is used to calculate and analyze the sensitivity of carbon emissions during the whole life cycle of the Qianluo 1# building. The results demonstrate that the total carbon output for the building over its entire life cycle is 155526 t, with 9006 t in the materialization stage, 145620 t in the use stage, and 900 t in the destruction stage. The sensitivity analysis results show that the heating carbon emission factor is the most sensitive and has the most significant potential for emission reduction, which is a critical factor in reducing residential building life cycle emissions.
Effect of heat treatment on the microstructure and mechanical properties of 7075 aluminum alloy cold-spray coatings
Authors: Zhang Zichang , Wang Renquan , Liu Ying
Published: June 2023

Cold Spray (CS) exhibit unique features due to the low temperatures involved. However, the CS coating are harder than the corresponding powders and bulk alloys, which results in a low toughness and then greatly limits the application of CS. To overcome this shortage, preheat treatment of powder and post-heat treatment of CS coating are applied to improve the performance of cold-sprayed 7075 aluminum alloy coatings in this work. With increasing temperatures of post-heat treatment, the tensile strength of the coatings increased from 228 MPa to 309 MPa with elongation of 2.46%. Microstructure analysis of the heat-treated coatings revealed that the improvement in mechanical properties was primarily due to an increase in the secondary phase. Accordingly, 7075 aluminum alloy powder was preheat treated at 200 °C and then used for cold spraying, which resulted in improved mechanical properties in the resultant coatings exhibiting a tensile strength of 302 MPa and an elongation of 3.87%. These findings provide valuable insights into the practical application of cold-spraying technology in the aviation field.
Research on influence of grain boundaries on the mechanical properties of 460 MPa refractory steel used for high-strength building structures
Authors: Wu Hong-Yu , Cong Jing-Hua , Liu Qi , Zhao Jing-Xiao , Wang Zhi-Quan , Wang Xue-Min , Liu Peng-Cheng
Published: June 2023

In this paper, the microstructure of Mo-type seismic refractory steel for building g, as well as different boundary densities and boundary ratios, are combined with elevated-temperature mechanical properties analysis to explore the laws of boundary for high-temperature performance. The results show that salt water cooling (SWC) and water cooling (WC) can obtain lath bainite with a higher content, and oil cooling (OC) with a lower cooling rate can obtain the microstructure of multiphase bainite + bulk ferrite. The boundary characterization results show that when the sample contains more high angle grain boundaries (Block and High-Packet boundaries), and the dislocation density is high, it can make it have better mechanical properties at room temperature. When the content of low angle boundary and low interfacial energy twin boundary (Σ3 boundary, which is mainly composed of V1/V2 variant pair) is high, it will have better microstructure stability after high temperature tempering, and the boundary density and dislocation density will decrease slightly, ensuring that it has better refractory performance.
Kei-apple-mediated NiO nanoparticles and biological studies: anti-inflammatory and cytotoxicity study against HeLa and HEK 293 cell lines
Authors: Adeyemi Jerry O
Published: June 2023

Nickel oxide (NiO) nanoparticles are gaining popularity in multiple fields owing to their useful properties. The application in biomedicine has been further enhanced by combining them with plant extracts that possess unique biological properties. In this report, NiO nanoparticles were synthesized by mediating the reaction process with the leaf extracts of Kei-apple (Dovyallis Caffra), a local fruit tree found in South Africa. Various characterization techniques such as x-ray diffraction (XRD), V–Vis spectroscopy (UV–Vis), transmission electron microscope (TEM), Scanning electron microscope (SEM), and Energy dispersive x-ray analysis (EDX) were employed to establish the different physicochemical properties of the prepared NiO material. The XRD report obtained confirmed the formation of NiO nanoparticles with an average crystallite size of 9 mm. Furthermore, the microscopic techniques showed that the material possessed a spherical-shaped structure, with diameter sizes smaller than 27.18 nm (average size of about 11 nm). The purity of the material was shown in the EDX analysis, in which the primary composition was only the elemental constituents of the NiO nanoparticles. The nanoparticles exhibited good cytotoxicity comparable to the 5-Fluorouracil in both the Human embryo kidney (HEK 293) and Human cervical cancer (HeLa) cell lines, with a half maximal inhibitory concentration (IC50) value of 0.00015 and 13.8 μg ml−1, respectively. The anti-inflammatory study, on the other hand, exhibited a weak anti-inflammatory effect in the used Bovine serum albumin denaturation assay. The finding here thus suggests that the Kei-apple mediated NiO nanoparticles can be safely used in different fields without causing any appreciable harm to the human body due to the specificity to the cancerous cell line and the observed weak viability in the used non-cancerous embryonic kidney cells.
Introducing radiomics model to predict active plaque in multiple sclerosis patients using magnetic resonance images
Authors: Khajetash Benyamin , Talebi Amin , Bagherpour Zahra , Abbaspour Samira , Tavakoli Meysam
Published: June 2023

Multiple Sclerosis (MS) is the most common non-traumatic disabling disease in young people. The prediction active plaque has the potential to offer new biomarkers for assessing the activity of MS disease. Consequently it supports patient management in the clinical setting and trials. This study aims to investigate the predictive capability of radiomics features for identifying active plaques in these patients using T2 FLAIR (Fluid Attenuated Inversion Recovery) images. For this purpose, a dataset images from 82 patients with 122 lesions was analyzed. Feature selection was performed using the Least Absolute Shrinkage and Selection Operator (LASSO) method. Six different classifier algorithms, namely K-Nearest Neighbors (KNN), Logistic Regression (LR), Decision Tree (DT), Support Vector Machine (SVM), Naive Bayes (NB), and Random Forest (RF), were employed for modeling. The models were evaluated using 5-fold cross-validation, and performance metrics including sensitivity, specificity, accuracy, area under the curve (AUC), and mean squared error were computed. A total of 107 radiomics features were extracted for each lesion, and 11 robust features were identified through the feature selection process. These features consisted of four shape features (elongation, flatness, major axis length, mesh volume), one first-order feature (energy), one Gray Level Co-occurrence Matrix feature (correlation), two Gray Level Run Length Matrix features (gray level non-uniformity, gray level non-uniformity normalized), and three Gray Level Size Zone Matrix features (low gray level zone emphasis, size zone non-uniformity, small area low gray level emphasis). The NB classifier demonstrated the best performance with an AUC, sensitivity, and specificity of 0.85, 0.82, and 0.66, respectively. The findings indicate the potential of radiomics features in predicting active MS plaques in T2 FLAIR images.
Traverse and longitudinal analysis of AA5083/AA6082 dissimilar joint
Authors: Segaetsho Molebogeng Oarabile Mmanyane , Msomi Velaphi , Moni Vuyani
Published: June 2023

This study investigates the mechanical and microscopic characteristics of the friction stir welded AA5083/AA6082 dissimilar joint. The welding process was performed at a rotational speed of 900 rpm, traverse speed of 60 mm min−1, and a tool tilt angle of 1°. Samples were extracted from the joint’s start, middle, and end positions in both the traverse and longitudinal directions. The analysis of these samples involved various tests, including microstructural analysis, bending, and tensile tests. The microstructural analysis revealed non-linear behaviour in both the longitudinal and traverse sampling directions along the joint. Specifically, there were notable differences in the microstructure between the different locations within the joint. In terms of mechanical properties, the ultimate tensile strength results of the traverse specimens were found to be higher compared to the specimens sampled longitudinally. This suggests that the joint’s strength may vary depending on the sampling direction. On the other hand, the flexural strength results showed a contrasting pattern, with the traverse specimens exhibiting lower strength values compared to the longitudinally sampled specimens.
Charge-sensing of a Ge/Si core/shell nanowire double quantum dot using a high-impedance superconducting resonator
Authors: Ungerer J H , Chevalier Kwon P , Patlatiuk T , Ridderbos J , Kononov A , Sarmah D , Bakkers E P A M , Zumbühl D , Schönenberger C
Published: June 2023

Spin qubits in germanium are a promising contender for scalable quantum computers. Reading out of the spin and charge configuration of quantum dots formed in Ge/Si core/shell nanowires is typically performed by measuring the current through the nanowire. Here, we demonstrate a more versatile approach on investigating the charge configuration of these quantum dots. We employ a high-impedance, magnetic-field resilient superconducting resonator based on NbTiN and couple it to a double quantum dot in a Ge/Si nanowire. This allows us to dispersively detect charging effects, even in the regime where the nanowire is fully pinched off and no direct current is present. Furthermore, by increasing the electro-chemical potential far beyond the nanowire pinch-off, we observe indications for depleting the last hole in the quantum dot by using the second quantum dot as a charge sensor. This work opens the door for dispersive readout and future spin-photon coupling in this system.
Dynamics of quadratic polynomials and rational points on a curve of genus 4
Authors: Fu Hang , Stoll Michael
Published: June 2023

Let

f
t

(
z
)
=

z
2

+
t

f_t(z)=z^2+t

. For any

z
∈

Q

z\in \mathbb {Q}

, let

S
z

S_z

be the collection of

t
∈

Q

t\in \mathbb {Q}

such that

z
z

is preperiodic for

f
t

f_t

. In this article, assuming a well-known conjecture of Flynn, Poonen, and Schaefer [Duke Math. J. 90 (1997), pp. 435–463], we prove a uniform result regarding the size of

S
z

S_z

over

z
∈

Q

z\in \mathbb {Q}

. In order to prove it, we need to determine the set of rational points on a specific non-hyperelliptic curve

C
C

of genus

4
4

defined over

Q

\mathbb {Q}

. We use Chabauty’s method, which requires us to determine the Mordell-Weil rank of the Jacobian

J
J

of

C
C

. We give two proofs that the rank is

1
1

: an analytic proof, which is conditional on the BSD rank conjecture for

J
J

and some standard conjectures on L-series, and an algebraic proof, which is unconditional, but relies on the computation of the class groups of two number fields of degree

12
12

and degree

24
24

, respectively. We finally combine the information obtained from both proofs to provide a numerical verification of the strong BSD conjecture for

J
J

.
Overlapping Iterated Function Systems from the Perspective of Metric Number Theory
Authors: Baker Simon
Published: June 2023

In this paper we develop a new approach for studying overlapping iterated function systems. This approach is inspired by a famous result due to Khintchine from Diophantine approximation which shows that for a family of limsup sets, their Lebesgue measure is determined by the convergence or divergence of naturally occurring volume sums. For many parameterised families of overlapping iterated function systems, we prove that a typical member will exhibit similar Khintchine like behaviour. Families of iterated function systems that our results apply to include those arising from Bernoulli convolutions, the{0,1,3}\{0,1,3\}problem, and affine contractions with varying translation parameter. As a by-product of our analysis we obtain new proofs of some well known results due to Solomyak on the absolute continuity of Bernoulli convolutions, and when the attractor in the{0,1,3}\{0,1,3\}problem has positive Lebesgue measure.

For eacht∈[0,1]t\in [0,1]we letΦt\Phi _tbe the iterated function system given by<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Phi Subscript t Baseline colon-equal StartSet phi 1 left-parenthesis x right-parenthesis equals StartFraction x Over 2 EndFraction comma phi 2 left-parenthesis x right-parenthesis equals StartFraction x plus 1 Over 2 EndFraction comma phi 3 left-parenthesis x right-parenthesis equals StartFraction x plus t Over 2 EndFraction comma phi 4 left-parenthesis x right-parenthesis equals StartFraction x plus 1 plus t Over 2 EndFraction EndSet period">Φt≔{ϕ1(x)=x2,ϕ2(x)=x+12,ϕ3(x)=x+t2,ϕ4(x)=x+1+t2}.\begin{equation*} \Phi _{t}≔\Big \{\phi _1(x)=\frac {x}{2},\phi _2(x)=\frac {x+1}{2},\phi _3(x)=\frac {x+t}{2},\phi _{4}(x)=\frac {x+1+t}{2}\Big \}. \end{equation*}We prove that eitherΦt\Phi _tcontains an exact overlap, or we observe Khintchine like behaviour. Our analysis shows that by studying the metric properties of limsup sets, we can distinguish between the overlapping behaviour of iterated function systems in a way that is not available to us by simply studying properties of self-similar measures.

Last of all, we introduce a property of an iterated function system that we call being consistently separated with respect to a measure. We prove that this property implies that the pushforward of the measure is absolutely continuous. We include several explicit examples of consistently separated iterated function systems.
Pure inner functions, distinguished varieties and toral algebraic commutative contractive pairs
Authors: Das B. , Sau Haripada
Published: June 2023

We study the pairs of commuting contractions that are annihilated by polynomials with a geometric condition on its zero set, herein called the toral algebraic pairs. Toral algebraic pairs of commuting isometries are characterized. In particular, a commuting pair of isometries is toral algebraic if and only if so is its minimal unitary extension. This triggers the natural question when a toral algebraic pair of commuting contractions lifts, in the sense of Andô, to a toral algebraic pair of commuting isometries. While this question remains open, a family including all the commuting contractive matrices is obtained for which the answer is affirmative. The study involves understanding of certain matrix-valued analytic functions, which in turn, throws new light on certain algebraic varieties which are studied extensively from operator- and function-theoretic point of view over the last two decades – the so-called distinguished varieties.
On forms in prime variables
Authors: Liu Jianya , Zhao Lilu
Published: June 2023

Let

F
1

F_1

, …,

F
R

F_R

be homogeneous polynomials of degree

d
⩾
2

d\geqslant 2

with integer coefficients in

n
n

variables, and let

F

=
(

F
1

,
…
,

F
R

)

\mathbf {F}=(F_1,\ldots ,F_R)

. Suppose that

F
1

F_1

, …,

F
R

F_R

is a non-singular system and

n
⩾

4

d
+
2

d
2

R
5

n\geqslant 4^{d+2}d^2R^5

. We prove that there are infinitely many solutions to

F

(

x

)
=

0

\mathbf {F}(\mathbf {x})=\mathbf {0}

in prime coordinates if (i)

F

(

x

)
=

0

\mathbf {F}(\mathbf {x})=\mathbf {0}

has a non-singular solution over the

p
p

-adic units

U

p

\mathbb {U}_p

for all prime numbers

p
p

, and (ii)

F

(

x

)
=

0

\mathbf {F}(\mathbf {x})=\mathbf {0}

has a non-singular solution in the open cube

(
0
,
1

)
n

(0,1)^n

.
Activation of CWI pathway through high hydrostatic pressure, enhancing glycerol efflux via the aquaglyceroporin Fps1 in Saccharomyces cerevisiae
Authors: Mochizuki Takahiro , Tanigawa Toshiki , Shindo Seiya , Suematsu Momoka , Oguchi Yuki , Mioka Tetsuo , Kato Yusuke , Fujiyama Mina , Hatano Eri , Yamaguchi Masashi , Chibana Hiroji , Abe Fumiyoshi
Published: June 2023

The fungal cell wall is the initial barrier for the fungi against diverse external stresses, such as osmolarity changes, harmful drugs, and mechanical injuries. This study explores the roles of osmoregulation and the cell-wall integrity (CWI) pathway in response to high hydrostatic pressure in the yeast Saccharomyces cerevisiae. We demonstrate the roles of the transmembrane mechanosensor Wsc1 and aquaglyceroporin Fps1 in a general mechanism to maintain cell growth under high-pressure regimes. The promotion of water influx into cells at 25 MPa, as evident by an increase in cell volume and a loss of the plasma-membrane eisosome structure, promotes the activation of Wsc1, an activator of the CWI pathway. Phosphorylation of the downstream mitogen-activated protein kinase Slt2 was increased at 25 MPa. Glycerol efflux increases via Fps1 phosphorylation, which is initiated by downstream components of the CWI pathway and contributes to the reduction in intracellular osmolarity under high pressure. The elucidation of the mechanisms underlying adaption to high pressure through the well-established CWI pathway could potentially translate to mammalian cells and provide novel insights into cellular mechanosensation.
From Fibromuscular Dysplasia to Arterial Dissection and Back
Authors: Huart Justine , Stoenoiu Maria S , Zedde Marialuisa , Pascarella Rosario , Adlam David , Persu Alexandre
Published: June 2023

Fibromuscular dysplasia (FMD) is an idiopathic and systemic non-inflammatory and non-atherosclerotic arterial disease. Fifteen to 25% of patients with FMD present with arterial dissection in at least one arterial bed. Conversely, a substantial number of patients with renal, carotid, and visceral dissection have underlying FMD. Also, while few patients with FMD develop coronary artery dissection, lesions suggestive of multifocal FMD have been reported in 30–80% of patients with spontaneous coronary artery dissection (SCAD), and the relation between these two entities remains controversial. The frequent association of FMD with arterial dissection, both in coronary and extra-coronary arteries raises a number of practical and theoretical questions: (i) Are FMD and arterial dissections two different facets of the same disease or distinct though related entities? (ii) Is SCAD just a manifestation of coronary FMD or a different disease? (iii) What is the risk and which are predictive factors of developing arterial dissection in a patient with FMD? (iv) What proportion of patients who experienced an arterial dissection have underlying FMD, and does this finding influence the risk of subsequent arterial complications? In this review we will address these different questions using fragmentary, mostly cross-sectional evidence derived from large registries and studies from Europe and the United States, as well as arguments derived from demographics, clinical presentation, imaging, and when available histology and genetics. From there we will derive practical consequences for nosology, screening and follow-up.
The effect of sedation and time after cardiac arrest on coma outcome prognostication based on EEG power spectra
Authors: Pelentritou Andria , Nguissi Nathalie Ata Nguepnjo , Iten Manuela , Haenggi Matthias , Zubler Frederic , Rossetti Andrea O , De Lucia Marzia
Published: June 2023

Early prognostication of long-term outcome of comatose patients after cardiac arrest remains challenging. Electroencephalography-based power spectra after cardiac arrest have been shown to help with the identification of patients with favourable outcome during the first day of coma. Here, we aim at comparing the power spectra prognostic value during the first and second day after coma onset following cardiac arrest and to investigate the impact of sedation on prognostication. In this cohort observational study, we included comatose patients (N = 91) after cardiac arrest for whom resting-state electroencephalography was collected on the first and second day after cardiac arrest in four Swiss hospitals. We evaluated whether the average power spectra values at 4.6–15.2 Hz were predictive of patients’ outcome based on the best cerebral performance category score at 3 months, with scores ranging from 1 to 5 and dichotomized as favourable (1–2) and unfavourable (3–5). We assessed the effect of sedation and its interaction with the electroencephalography-based power spectra on patient outcome prediction through a generalized linear mixed model. Power spectra values provided 100% positive predictive value (95% confidence intervals: 0.81–1.00) on the first day of coma, with correctly predicted 18 out of 45 favourable outcome patients. On the second day, power spectra values were not predictive of patients’ outcome (positive predictive value: 0.46, 95% confidence intervals: 0.19–0.75). On the first day, we did not find evidence of any significant contribution of sedative infusion rates to the patient outcome prediction (P > 0.05). Comatose patients’ outcome prediction based on electroencephalographic power spectra is higher on the first compared with the second day after cardiac arrest. Sedation does not appear to impact patient outcome prediction.
Human dignity in organisations: the cooperative ideal
Authors: McMahon Cian
Published: June 2023

This paper critically evaluates the liberal-humanist critique of neoclassical microeconomics and shareholder-driven corporate governance to articulate a more realistic cooperativist–humanist organisational philosophy of practice. Through an engagement with pluralist heterodox economics, it attempts to reconcile with contemporary concerns and philosophical developments around social ecology and care ethics. Our specific contribution is to develop a microfoundational complement to the macro-relational analysis of leading radical philosophical and political-economic thinkers on the Latin American left. In particular, the worker-inclusive multistakeholder cooperative (MSC) form is arrived at as the ideal firm-level organisation through which to promote diverse human (and non-human) dignity, understood through the lens of an affective-relational ethics of care.
Right ventricular to pulmonary artery coupling and outcome in patients with cardiac amyloidosis
Authors: Tomasoni Daniela , Adamo Marianna , Porcari Aldostefano , Aimo Alberto , Bonfioli Giovanni Battista , Castiglione Vincenzo , Franzini Maria , Inciardi Riccardo Maria , Khalil Anas , Lombardi Carlo Mario , Lupi Laura , Nardi Matilde , Oriecuia Chiara , Pagnesi Matteo , Panichella Giorgia , Rossi Maddalena , Saccani Nicola , Specchia Claudia , Vergaro Giuseppe , Merlo Marco , Sinagra Gianfranco , Emdin Michele , Metra Marco
Published: June 2023

Aims

To investigate the prognostic value of the right ventricle-to-pulmonary artery (RV-PA) coupling in patients with either transthyretin (ATTR) or immunoglobulin light-chain (AL) cardiac amyloidosis (CA).

Methods and results

Overall, 283 patients with CA from 3 Italian high-volume centres were included (median age 76 years; 63% males; 53% with ATTR-CA, 47% with AL-CA). The RV-PA coupling was evaluated by using the tricuspid annular plane systolic excursion/pulmonary artery systolic pressure (TAPSE/PASP) ratio. The median value of TAPSE/PASP was 0.45 (0.33–0.63) mm/mmHg. Patients with a TAPSE/PASP ratio <0.45 were older, had lower systolic blood pressure, more severe symptoms, higher cardiac troponin and N-terminal pro-B-type natriuretic peptide levels, greater left ventricular (LV) thickness, and worse LV systolic and diastolic function. A TAPSE/PASP ratio <0.45 was independently associated with a higher risk of all-cause death or heart failure (HF) hospitalization [hazard ratio (HR) 1.98, 95% confidence interval (CI) 1.32–2.96; P = 0.001] and all-cause death (HR 2.18, 95% CI 1.31–3.62; P = 0.003). The TAPSE/PASP ratio reclassified the risk of both endpoints [net reclassification index 0.46 (95% CI 0.18–0.74) P = 0.001 and 0.49 (0.22–0.77) P < 0.001, respectively], while TAPSE or PASP alone did not (all P > 0.05). The prognostic impact of the TAPSE/PASP ratio was significant both in AL-CA patients (HR for the composite endpoint 2.47, 95% CI 1.58–3.85; P < 0.001) and in ATTR-CA (HR 1.81, 95% CI 1.11–2.95; P = 0.017). The receiver operating characteristic curve showed that the optimal cut-off for predicting prognosis was 0.47 mm/mmHg.

Conclusion

In patients with CA, RV-PA coupling predicted the risk of mortality or HF hospitalization. The TAPSE/PASP ratio was more effective than TAPSE or PASP in predicting prognosis.