bluuebunny/crossref_metadata_2025 huggingface dataset:
A transformer winding and core mechanical fault diagnosis approach based on VMD-MFE and GWO-MKELM
Authors: Sun Yuxiao , Zhang Ruizhi , Zhu Yichao , Wang Yizhou , Chen Yichao
Published: October 2024

In response to the difficulty of accurately diagnosing weak internal faults in transformers using traditional diagnostic methods, this paper proposes a transformer mechanical fault diagnosis approach relying on a combination of variational mode decomposition (VMD) and grey wolf optimization algorithm optimized multiple kernel extreme learning machine (GWO-MKELM). Firstly, VMD obtains the modal components of different orders of the raw vibration signal and uses multi-scale fuzzy entropy (MFE) to compute the entropy value of the optimal modal component. Secondly, to thoroughly apply the diagnostic ability of KELM, a mixed kernel function is constructed using the Gaussian radial kernel function and polynomial kernel function, and a GWO-MKELM diagnostic model is established. Finally, the experimental data proves the effectiveness and superiority of the suggested diagnostic model. This method could supply direction for the formulation of transformer condition maintenance policies.
The influence of traction load on power quality of weak power grid
Authors: Wang Heng , Liu Haijun , Wang Tongxun , Li Yaqiong
Published: October 2024

Due to the characteristics of non-linearity, impact, and asymmetry of the traction load of electrified railway, a large number of harmonic currents and negative sequence currents will be generated after the traction load is connected to the power grid, which will cause the power quality level of adjacent power sources and users to decline, and may seriously affect the power delivery and normal consumption of users. This paper evaluates the power quality problems caused by traction load access through simulation. The limited power of the electric locomotive is put forward in the weak grid area, and the speed of the locomotive is reduced to ensure safe passage through the weak grid area. The simulation results indicate that by appropriately reducing the power output of electric locomotives, we can achieve compliance with national standards for key electrical energy indicators. Additionally, this reduction can mitigate the impact of electrified railways on surrounding users, while maintaining the safe operation of the railways in areas with limited power grid capacity.
Optimal configuration of distributed energy storage based on the identification of voltage-vulnerable nodes
Authors: Wang Zheng , Zhao Shengnan , Wang Luhao , Song Haixia
Published: October 2024

With the rapid growth of distributed photovoltaic power generation and its integration into the grid, the power supply pressure on the grid has significantly intensified, and problems such as voltage exceeding the limit and power backflow are prone to occur. Addressing the issues of voltage surpassing thresholds and power reversal in distribution networks due to distributed photovoltaic systems through strategic placement of distributed energy storage has emerged as a principal research target. To this end, this paper first utilizes the Dempster-Shafer evidence theory to calculate the vulnerability of distribution network nodes based on vulnerability indices, selecting the vulnerable nodes. Subsequently, by analyzing the correlation between power and voltage, the sensitivity of voltage at distribution network nodes is determined. A distributed energy storage voltage regulation planning model is established using relevant constraints of energy storage in the distribution network and line-related conditions. Additionally, the voltage regulation scenarios that consider tap changers and static VAR compensation (SVC) are calculated. Ultimately, the efficacy of the suggested approach is validated through simulation on the IEEE 33-bus system.
Application of sound and vibration recognition technology based on optimized features in underground cable external breakage prevention
Authors: Su Qi , Chen Zhongbin , Li Wei
Published: October 2024

This study focuses on enhancing the accuracy of engineering vehicle identification through the optimization of acoustic characteristics and the use of the UBM-GMM algorithm, aiming to reduce the operation time of the identification process and thereby better prevent underground cable damage. The research compared three types of features: traditional MFCC features, combined feature M1, and optimized feature M2. The results indicated that the optimized feature M2 achieved a recognition accuracy of 94%, with the shortest training and recognition times being 127.017 seconds and 0.86 seconds, respectively. An AUC evaluation of 0.94 demonstrates the model’s strong recognition performance. The study validated the effectiveness of vibration acoustics recognition technology based on optimized acoustic properties in improving the identification rate of engineering vehicles and shortening the recognition time, providing crucial technical support for the timely protection of underground cables.
Performance analysis of hard-switching FSO/RF hybrid link system in foggy weather conditions
Authors: Yang Ruike , Liu Chen
Published: October 2024

Free space optical communication is vital for modern high-speed communication, yet it encounters considerable obstacles in foggy weather conditions. This study utilizes a combination of the Malaga model for turbulence-induced errors and a stochastic model for the fog to derive formulations that estimate both the likelihood of signal loss and the mean bit error rate in the integrated channel of the FSO link. Moreover, by employing a threshold hard-switched FSO/RF hybrid link system, our evaluation focuses on determining the outage probability and the average bit error rate for the composite link system. By analyzing the performance metrics of both the sole FSO link and the combined FSO/RF link, it is clear that the hybrid system shows a marked improvement in reducing the chances of signal interruption, which highlights the enhanced reliability offered by the integration of FSO/RF links in maintaining consistent communication system operations.
Design of pulse width modulation circuit based on PWM modulation
Authors: Du Wenhe , Chai Ruili , Chen Shuoyu , Wang Lei
Published: October 2024

The key to the modulation technology of the switching power supply is to control the on-off of the power switch and realize the real-time adjustment of the duty cycle with the system through the control signal. In order to improve the realization accuracy of the control signal, a generation method different from the traditional pulse width modulation signal is proposed. The two edge signals are processed by the RS trigger to generate the pulse width modulation signal. The circuit is designed and simulated in SMIC 0.18 μm CMOS process. In the full feedback current range, the duty cycle of the pulse width modulation signal decreases linearly, which can effectively improve the conversion efficiency of the power supply.
Multi-wave impedance modeling and transient characterization of lightning strikes on long-span transmission towers
Authors: Zhang Junfeng , Wang Chaoqun , Liu Chunlin , Jin Miao , Bao Hua , Zhu Bo , Zou Demu
Published: October 2024

With the increase in crossing distance, the height of long-span transmission towers suitable for UHV transmission lines is also increasing. The ultra-high height and ultra-long span increase the probability of long-span sections being struck by lightning. Therefore, the lightning strike long-span transmission tower model and its transient characteristics analysis are particularly important for lightning protection. In this paper, considering the concrete structure of the main material members of the long-span transmission tower, a multi-wave impedance modeling method for the tower is proposed. Firstly, the tower is divided into three parts: nominal height, upper tower body, and cross arm. The wave impedance of each part is calculated using finite element simulation, empirical formula, and parallel multi-conductor equivalent impedance theory. Then, the simulation verifies the electromagnetic transient characteristics of the multi-wave impedance model of the long-span transmission tower. Based on the ATP-EMPT simulation software, the segmented Hara model is constructed with the proposed multi-wave impedance refinement model, and the simulation results are consistent, which verifies the validity of the model. Finally, the lightning transient characteristics of long-span transmission towers under different conditions are simulated and analyzed, which provides guidance for its lightning protection design.
Research on an optimal load of sliding electrical contact based on the SSA-LS_SVM model
Authors: Chi Yixuan , Cao Mingyuan
Published: October 2024

During the operation of the pantograph-catenary system, the contact current, wear amount, and friction coefficient will affect the determination of the optimal pressure load. A self-made testing machine simulates the actual operation of the pantograph catenary, and the relationship between various factors and pressure load under different working conditions is analyzed. The least squares support vector machine model is optimized by the sparrow algorithm to establish the SSA-LS_SVM prediction model with the optimal load as the output. The Pareto solution set is obtained by multi-objective optimization of the optimal load with a multi-objective genetic algorithm. The weight of the three variables is obtained by the entropy weight method, and the multi-objective optimization problem is transformed into a single-objective optimization problem to determine the optimal pressure load.
Analysis of wind loads for a new type of insulated crossing frame in transmission lines
Authors: Wei Shutian , Liu Zhengmao , Wu Xiong , Fan Yinwei , Zhang Hui
Published: October 2024

A composite insulation material crossing frame has been designed to meet the safety requirements of transmission line crossing construction. The upper part of the frame is made of composite materials, which consist of modified polyurethane and reinforced fibers. The bottom is made of steel components, with a modular design that can be assembled according to actual needs. This article presents the mechanical performance analysis of the crossing frame under different wind loads. Through finite element analysis, the mechanical performance of the crossing frame meets the requirements of the specifications. The crossing frame structure is reasonable, safe, and reliable, and composite materials have corrosion resistance. It plays an important role in safety protection in transmission line crossing projects and has high application and promotion value.
Insulator defect detection algorithm based on YOLOv8-ISDD
Authors: Tang Jiarui , Peng Hong
Published: October 2024

Insulators are widely used in transmission lines due to their good insulation performance and pollution resistance. The damage to insulators will affect their service life and insulation performance, which brings potential safety hazards to transmission lines. With the replacement of manual inspection with UAV inspection, image detection technology based on deep learning is gradually combined with UAV inspection. Usually, the insulator defect target accounts for a small proportion of the acquired image. Therefore, the manuscript introduces an enhanced algorithm for detecting flaws on the surface of insulators, designated as YOLOv8-ISDD. In the backbone network, the YOLOv8-ISDD algorithm introduces reparameterized convolution (Repconv) to enhance the network’s capability in extracting features of defects; to fuse the features of different resolutions, PANet in the neck network is replaced by Bi-FPN for integrating features. Within the head network, the multi-scale detection head output is used to increase the diminutive object identification stratum and boost the algorithm’s capability to discern lesser targets. Experiments show that the mAP@0.5 of the YOLOv8-ISDD algorithm is 88.9%, which is 6% higher than that of the original YOLOv8 algorithm, indicating that YOLOv8-ISDD can detect insulator defects more accurately.
Improved second-order consensus control method
Authors: Xing Wenshuo , Zhou Shien
Published: October 2024

In this paper, due to the delay of communication and the time variability of the reference state, the traditional consistency algorithm is not very good at fitting the time-varying reference state, so this paper proposes an improved second-order consistency governing equation, adding time-varying factors and delay terms. The UAV communication model and cluster motion model are presented, and the correctness of the new algorithm is verified by theoretical derivation. Comparing the experimental result graph of the improved algorithm with the traditional second-order consistency calculation, it can be found that the proposed algorithm has a better fitting effect in the time-varying reference state.
Feature selection method for future-state power grid operation mode based on semi-supervised learning
Authors: Li Jiachen , Liu Baozhu , Zhang Shuang , Ma Jing , Wang Jiecong , Ma Jun , Shi Chen , Wang Bing
Published: October 2024

With the rapid development of grid interconnection and the large-scale integration of renewable energy, the number of key features in the power system is very large. To proactively monitor the status of future power grids, it is necessary to extract key features that comprehensively reflect their operation modes from the operational data. This paper presents a feature selection method for power grid operation modes based on semi-supervised learning. The method is designed to consider the semi-supervised dataset of the future-state power grid. The efficient semi-supervised feature selection method based on the eigenspace model and manifold regularization can be used to quickly and accurately obtain the key features reflecting the way the grid is operated, and its validity is verified at the IEEE39-bus system.
Iterative decoding algorithm for LDPC-RS product codes based on joint check
Authors: Zhang Dang , Zhang Zhongmin , Zheng Fenghao
Published: October 2024

Aiming at the problem of error in RS decoding judgment, in this paper, when constructing LDPC-RS product code, LDPC code is used as the outer code, RS code is used as the inner code, and CRC encoding is applied to RS code to improve the probability of decoding correct judgment of RS code during error correction. This paper also proposes a set of low-complexity iterative decoding schemes, which aims to improve the decoding efficiency of product codes. During the decoding process, the decoding results are verified by means of the checksum of the joint RS code and CRC at the time of decoding, and the correct code words in the previous iteration are corrected by the soft value. Simulation data show that the LDPC-RS product code effectively improves its performance, and for the product code composed of the combination of LDPC (576, 288) and RS (255, 241), when the signal-to-noise ratio Eb/N0 is 2.4 dB, its bit error rate is reduced by two orders of magnitude compared with the case without joint iterative optimization.
Double layer optimization control strategy for distribution network based on population algorithm and demand optimization
Authors: Wang Yang , Zheng Youzhuo , Tang Kang , Yang Zhong , Wen Lei
Published: October 2024

The double-layer optimization control method for distribution networks based on complementary electricity and demand response designed in this article has two significant advantages. Firstly, it takes into account the complex electricity production and transportation situation in mountainous areas and comprehensively optimizes and combines scheduling for distributed energy transportation and access to the distribution network. Secondly, considering the network with the player side, a double-layer optimization management is carried out to achieve a win-win situation for distributed energy between the distribution network and the microgrid. The present invention aims to search for multiple optimal solutions in multi-objective optimization and combined scheduling of distributed energy. In double-layer optimization management, the upper function is the maximization of the distribution network operator, and the lower objective function is to minimize the operating costs expected by each user.
Optimal allocation strategy for distribution network resources based on CC-OPF
Authors: Zheng Youzhuo , Hao Shuqing , Miao Yu , Zhang Yang , Song Zihong
Published: October 2024

A distribution network resource optimization allocation strategy considering the optimal curtailment rate is proposed to achieve the most economical consumption of photovoltaics. This strategy is based on the opportunity-constrained optimal power flow method (CC-OPF) to solve the hierarchical resource allocation model for photovoltaic distribution networks, effectively reducing network losses and abandoned light, and improving the system’s economy, safety, and flexibility. Finally, IEEE-33 nodes are selected as the example system for analysis, and the outcomes of the study confirm the validity and practicality of the model that is suggested.
Research on the development trends of vehicular OTA antenna testing technology
Authors: Zhou Lusha , Chen Rongquan , Wang Ruohao , Zhan Xi , Wu Weisheng , Zhong Jianhui
Published: October 2024

With the continuous advancement of communication technology, vehicles are becoming electrified, autonomous, and connected. Compared to conventional vehicles, connected automated vehicles contain many wireless technologies, including cellular (2G, 3G, LTE), Bluetooth, Wi-Fi, Global Navigation Satellite System (GNSS), collision avoidance radar, and more. Therefore, characterizing wireless onboard systems such as automobile-mounted antennas in-vehicle environments is important. Currently, over-the-air (OTA) measurement systems and techniques are widely used to evaluate the performance of automobile-mounted antennas. This article elaborates on the development trends of automotive OTA antenna testing technology, covering aspects such as standards development, testing principles, testing solutions, and engineering experience.
Gridless mixed-field sources localisation algorithm based on covariance matrix reconstruction
Authors: Chen Mengya , Lin Wei , Zhao Yongwei , Wang Guannan , Wu Leibeini , Tong Hua
Published: October 2024

Most existing mixed-field sources localization algorithms for the sparse array are based on fourth-order cumulant, which are computationally complex and unable to localize Gaussian sources. To realize the mixed-field localization of Gaussian sources, this paper introduces an algorithm for mixed-field source localization that utilizes the interpolation and reconstruction of the covariance matrix. The proposed algorithm uses an oblique projection operator to extract the near-field source components from the mixed-field sources and the atomic norm minimization (ANM) method to interpolate and reconstruct the covariance matrix. By using the anti-diagonal element of the reconstructed covariance matrix to eliminate the influence of the range parameter, the angle estimations of the near-field sources can be obtained. The proposed algorithm is a second-order statistic-based algorithm that can be applicable to both Gaussian and non-Gaussian sources. Simulation results verify the performance advantages of the proposed algorithm.
Informer-CSI predict CSI for non-terrestrial networks
Authors: Ding Junhao , Luo Zhiyong
Published: October 2024

With the continuous development of non-terrestrial networks, non-terrestrial networks are increasingly expanding to cover remote areas that terrestrial networks cannot reach. Due to the propagation characteristics between satellites and terrestrial infrastructure, Channel State Information (CSI) is often outdated, significantly compromising communication performance. Each connection process between satellites and terrestrial infrastructure can be likened to the sun’s rising and setting. To address this challenge, we leverage historical CSI and model the estimation of Channel State Information as a long-term sequence prediction problem. We employ a Transformer model to predict CSI. Simulation results demonstrate that this prediction method offers outstanding performance improvements compared to other neural network algorithms and applies to Low Earth Orbit (LEO) satellites at different orbital altitudes.
Multiple harmonics suppressing methods based on generalized resonant extended state observer: methodology and analysis
Authors: Cheng Tianji , Wu Ze , Liu Zhiwen , Wei Shengjie , Wang Ranjun , Liu Enhai
Published: October 2024

The problem of multiple harmonics suppression using a high-order observer, also named generalized proportional integral observer (GPIO), is studied in this paper. Firstly, owing to the insufficient presentation of the conventional improvement of GPIO aiming at harmonic uncertainties, this paper extends it to a more general form based on lumped disturbance decomposition named generalized resonant extended state observer (GRESO). Next, the equivalence between the GRESO-based controller and the two-degree-of-freedom internal model controller (IMC) structure is revealed, which makes the frequency analysis of it possible, followed by the systematic performance analysis of the GRESO-based controller concerning anti-disturbance capability, tracking performance and noise sensitivity. Finally, comparative simulations further verify the superiority of the GRESO compared with the traditional GPIO from different perspectives. From the performance analysis and simulation, it is concluded that the proposed GRESO-based controller has better performance in harmonics repression without affecting the tracking performance and noise sensitivity compared with the GPIO of the same order when the frequencies of the harmonics are known.
Affine formation control of discrete-time second-order multi-agent systems with a fixed communication period
Authors: Zheng Jiafeng , Li Jianzhen
Published: October 2024

This study delves into the affine formation problem within discrete-time multi-agent systems, emphasizing the significance of the fixed communication period. It explores both undirected and directed graphs to model communication networks among followers. Utilizing bilinear transformation to analyze the characteristic equation of the error system, this paper establishes sufficient conditions to attain the desired control objective. The validity of the proposed theoretical findings is confirmed through comprehensive numerical simulations.
Research on clutter suppression method based on velocity distribution in vegetation clutter environment
Authors: Sang Ze , Song Yongping , Dai Yongpeng , Xu Zhuo , Zhou Xiaolong , Li Kemeng , Jin Tian
Published: October 2024

A radar is a kind of radio detection equipment that is often used as a sensor for target detection and location. In modern border defense work, monitoring, early warning, and others are often based on the vegetation environment. Therefore, detecting concealed personnel targets in a vegetation environment is of great significance. Generally, the motion of branches, leaves, and plants under natural conditions will produce strong vegetation clutter, resulting in many false alarms and a sharp decrease in detection probability. To find a reasonable way to suppress vegetation clutter, this paper focuses on vegetation clutter modeling and filter designing. Firstly, we review previous research on clutter suppression and find most of the clutter modeling work focused on clutter itself but ignored the velocity difference between clutter and target, which can be used for clutter suppression. Then, the velocity distributions of vegetation clutter and targets are extracted from measured data. According to the intersection of two velocity distribution fitting curves with the least mean square error, the filter’s cutoff frequency is calculated, and an optimal signal-to-noise ratio filter is designed based on the Neyman-Pearson criterion. Finally, an experiment on vegetation clutter suppression was completed. Results show that the proposed method can achieve an average of 8.2 dB and 11 dB improvement in signal-to-noise ratio compared with traditional suppression methods.
Application of dynamic loop resistance test in the development process of 220kV new type fast switch
Authors: Zhang Shuai , Yang Yong , Wei Bo , Li Lele , Wang Bin , Yang Wanbo , Cui Zhuye , Huang Junhao
Published: October 2024

In order to accumulate early data of dynamic loop resistance of the fast switch, the evaluation of subsequent production use and the degree of contact ablation is carried out. This paper selects three prototypes for trial production and three engineering prototypes to collect and analyze dynamic loop resistance data. Three engineering machines before and after life test of the life prototype, before and after the capacity prototype T100a and electrical life test. Test data results are as follows: a) No. 1 prototype (lifetime prototype) showed high consistency before and after life test, indicating that main contact resistance, main contact separation and closing time have high consistency. b) After electromechanical life test of no. 3 trial sample, the equipment shall be disassembled, inspected and reassembled. Assembly process may not be in place, causing dynamic resistance stroke curve to have slightly more burrs in the closing over-travel stage, and loop resistance reaches 131 μΩ. Shows that assembly quality has a great influence on dynamic loop resistance. c) Arc contacts of the three phases of engineering machine are in good condition, and main contact resistance, separation and closing time of main contacts have high three-phase consistency. Loop resistances of three phases are 77 μΩ. 77 μΩ, and 76 μΩ, respectively. The loop resistance difference is 1.3%. Raw data of fast switching dynamic loop resistance are analyzed. It provides necessary data support for subsequent quick switch operation and maintenance and fault analysis.
Glibenclamide-encapsulated Liposomes alleviate LPS-induced Inflammatory Cascade through NLRP3 inhibition in macrophages
Authors: Kanika  , Prakash Ravi , Kumar Ajay , Mahajan Shubham , Ali Nemat , Raza Syed Shadab , Khan Rehan
Published: October 2024

Inflammation is a vital immune response for survival during infection and tissue damage. It is critical in maintaining normal tissue homeostasis by orchestrating appropriate inflammatory mediators. Macrophages, integral to innate immunity, respond to lipopolysaccharide (LPS) present in gram-negative bacteria by releasing inflammatory cytokines. Utilizing nanotechnology for drug delivery have been proven with enhanced therapeutic approaches by targeting the suppression of inflammatory mediators and cytokines. Recent studies have provided insights into the role of inflammasomes in intracellular processes linked to inflammation. Glibenclamide (GLB), a sulfonylurea used in type 2 diabetes treatment, has emerged as a potent inhibitor of the NLRP3 inflammasome, showing promise in alleviating inflammation-associated injuries. To overcome the limitations of GLB, such as low aqueous solubility and high permeability, in this study, methyl-PEG-DSPE lipids were used to develop GLB-loaded nanoliposomes. The size of blank liposome was measured to be 120 nm. Anionic GLB-loaded liposomes, sized 146 nm with spherical morphology, effectively suppressed the expression of NLRP3 mediators (caspase-1, ASC, IL-1B, and IL-18) and various reactive oxygen species mediators compared to free GLB, reducing LPS-induced inflammatory responses in RAW264.7 macrophages. This suggests the potential of GLB-loaded liposomes as a therapeutic agent for inflammation-related disorders, warranting further in-vivo investigation.
Novel super stack passivation in AlGaN/GaN HEMT for power electronic applications
Authors: Arunraja A , Suresh K , Senthilnathan S
Published: October 2024

A super-stack passivation technique is proposed for an AlGaN/GaN HEMT in order to improve the breakdown voltage and cutoff frequency. The performance of the proposed technique is benchmarked against a conventional GaN HEMT. The analysis and investigation are carried out using Technology Computer-Aided Design (TCAD). The simulation results are validated with experimental data. It is observed that the breakdown voltage of the conventional and proposed devices is 356V and 449V, respectively. In contrast to the conventional device, the breakdown voltage of the proposed device is improved by 21%. This is the manifestation of the suppression of the electric field by the super-stack passivation technique in the proposed device. Furthermore, it is also observed that the Johnson’s figure of merit in the proposed GaN-HEMT is also improved.
Suitability of using mussel shells as partial replacement of aggregates in self-compacting concrete
Authors: Bekkeri Gopal Bharamappa , Shetty Kiran K , Nayak Gopinatha , Saheb Sinan Asenar , Rao K Balakrishna
Published: October 2024

The handling of mussel shell wastes in coastal regions presents an issue that may be addressed by using mussel shells as a construction material. Shells from waste mussels replace aggregate in concrete, whole or in part. The shells of the mussels are well suited to be incorporated as aggregate into a concrete mix since they are primarily composed of limestone, a substance similar to the other ingredients in concrete. The current study focuses on the suitability of using mussel shells to replace aggregates in self-compacting concrete (SCC). The aggregates were substituted with mussel shells in 5, 10, 15, and 20 percentages. The mixes were initially tested for workability, including slump cone test, L-box test, flow test, and V-funnel test, followed by determining the mechanical behavior, such as flexural strength (FS), compressive strength (CS), and split tensile strength (STS). Also, the microstructural analysis of the mixes was done using scanning electron microscopy (SEM) and energy dispersive x-ray (EDX). The results showed that the concrete’s fresh, hardened, and microstructural properties could be improved by substituting aggregates with mussel shells up to 15%. Some prime results of the SCC mix exhibited a slump flow value range of 600–700 mm, a V-funnel flow time of 10–13 sec, an L-box test ratio greater than 0.8, CS of 41.97–52.93 MPa, STS of 3.69–4.18 MPa, and FS of 3.75–4.28 MPa. The study concludes that better-performed SCC can be produced at an optimum dosage of 15% mussel shells to partially replace aggregates.
Ultra-compact on-chip camera based on optoelectronic compound eyes with nonuniform ommatidia
Authors: Zhu Lin , Liu Yu-Qing , Wan Jia-Yi , Sun Zhi-Juan , Han Dong-Dong , Chen Qi-Dai , Zhang Yong-Lai
Published: October 2024

Compound eyes (CEs) that feature ultra-compact structures and extraordinary versatility have revealed great potential for cutting-edge applications. However, the optoelectronic integration of CEs with available photodetectors is still challenging because the planar charge-coupled device (CCD)/complementary metal oxide semiconductor (CMOS) detector cannot match the spatially distributed images formed by CE ommatidia. To reach this end, we report here the optoelectronic integration of CEs by manufacturing 3D nonuniform ommatidia for developing an ultra-compact on-chip camera. As a proof-of-concept, we fabricated microscale CEs with uniform and nonuniform ommatidia through femtosecond laser two-photon photopolymerization, and compared their focusing/imaging performance both theoretically and experimentally. By engineering the surface profiles of the ommatidia at different positions of the CE, the images formed by all the ommatidia can be tuned on a plane. In this way, the nonuniform CE can be directly integrated with a commercial CMOS photodetector, forming an ultra-compact CE camera. Additionally, we further combine the CE camera with a microfluidic chip, which can further serve as an on-chip microscopic monitoring system. We anticipate that such an ultra-compact CE camera may find broad applications in microfluidics, robotics, and micro-optics.
Effect of high pressure-low plasticity burnishing on the mechanical and microstructural behaviour of copper foil interlayered FSW aluminium alloys
Authors: Vignesh A R , R Oyyaravelu
Published: October 2024

This study delves into the impact of high pressure-low plasticity burnishing (HP-LPB) on the mechanical and microstructural behaviour of friction stir welding (FSW) joints, specifically involving AA5052 and AA6082 aluminium alloys. Notably, copper foil (CF) is introduced as a novel element in the HP-LPB process to enhance the weld strength. The experiments were conducted with the tool rotational speeds (TRS) of 1000, 1100, and 1200 RPM, each paired with the welding speeds (WS) of 20, 25, and 30 mm min−1, and tool tilt angle (TTA) of 0°, 1°, and 2°. Mechanical behaviour is assessed through tensile testing along with microhardness measurements, revealing the advantages of HP-LPB with CF in enhancing joint strength and toughness. The microstructural analysis reveals the dissolution of precipitates, highlighting the influential role of copper foil in the improvement of joint efficiency. From the weld without a CF interlayer, a maximum tensile strength of 188 MPa was achieved at a TRS of 1200 RPM, WS of 25 mm min−1 and TTA of 2°. The post-processed FSW sample interlayered with copper foil, exhibited an improvement in joint efficiency by 87% at the optimum process parameter. This research demonstrates that the use of copper foil interlayers combined with HP-LPB treatment can substantially enhance the mechanical properties and structural integrity of FSW aluminum alloys, offering a valuable solution for advanced industrial applications.
Numerical investigation of the effect of laser peen forming process parameters on 1060 aluminium sheets under preload
Authors: Kumar Muramulla Naveen , Tiwari Gaurav , Baral Subrat Kumar , Ratna Sunil B , Dumpala Ravikumar
Published: October 2024

Laser peen forming process changes the shape of the metal sheet or plate by plastic deformation caused by laser induced mechanical shock wave. The bending behavior of 1060 aluminium sheets under laser peen forming (LPF) are studied numerically taking into account the various laser peening process parameters for two distinct cases; with and without preload. Modal analysis has been performed on 3D finite element model (FEM) to stop post-shock oscillations. A time-dependent and space-dependent pressure distribution is applied to the laser-peened area along with preload at the free end. The numerical comparison of bending angles and surface profile of 1060 aluminium sheets under laser peen forming are studied for both the cases, with and without preload. Preloading provides better surface profile for same bending angle for a no laser shock overlap.
A novel step-up modified SEPIC converter to enhance photovoltaic system performance using a hybrid ANN-PSO algorithm
Authors: Moaazer Rawia , Ajel Ahmed R , Bonnya Mahdi F
Published: October 2024

This paper presents a modified SEPIC converter intended for solar applications and high-voltage devices. This design combines a discrete inductor-circuit (3 diodes and 2 inductors) with a switched capacitor-circuit (2 capacitors and 2 diodes), achieving a voltage gain six times the input voltage at a low commitment cycle of 0.5 without using a double inductance. Solar power systems are subject to fluctuations in production due to temperature and radiation changes, which leads to variable and unstable voltage. The SEPIC rectifier converter converts variable voltage into regular DC voltage suitable for powering loads, enhancing the energy extraction efficiency of solar panels. A simulation was performed using Simulink/MATLAB to test the overall performance of the converter based on the ANN-PSO algorithm, where the modified SEPIC was compared with the conventional converter. The results confirmed the effectiveness of the transformer in extracting energy with 100% efficiency from the PV panels. The transformer has proven its effective performance in dealing with photovoltaic systems. The output voltage control was evaluated using a PI controller based entirely on the ANN-PSO optimization algorithm, Where ANN predicts radiation and temperature and trains and teaches it with the pre-existing parameters in the neural to reach the target while the pso algorithm improves the neural results and achieves the optimal performance to reach the best control. and the simulation results confirmed the effectiveness of the proposed approach.
Satellite remote sensing reveals the footprint of biodiversity on multiple ecosystem functions across the NEON eddy covariance network
Authors: Gomarasca Ulisse , Duveiller Gregory , Pacheco-Labrador Javier , Ceccherini Guido , Cescatti Alessandro , Girardello Marco , Nelson Jacob A , Reichstein Markus , Wirth Christian , Migliavacca Mirco
Published: October 2024

Biodiversity relates to ecosystem functioning by modulating biogeochemical cycles of carbon, water, energy, and nutrients within and between multiple biotic and abiotic components of the ecosystems. However, large-scale, systematic measurements of plant biodiversity are still lacking, and the effects of biodiversity on measured biogeochemical processes are understudied. Here, we combined alpha (α) and beta (β) taxonomic measurements, spectral diversity from satellite observations, structural properties of the vegetation, and climatic drivers to assess the effect of biodiversity on ecosystem functional properties. Ecosystem functional properties were computed from eddy-covariance fluxes at 44 sites of the National Ecological Observatory Network. Based on the spectral variation hypothesis, we used the near-infrared reflectance of vegetation (NIRv) derived from Sentinel-2 satellite imagery to compute Rao’s quadratic entropy (Rao Q), a distance metric related to spatial heterogeneity. Using an automatic model averaging technique, we found that biodiversity proxies hold substantial explanatory power when predicting several ecosystem functions related to carbon and water exchange. In particular, NIRv-based Rao Q (RaoQNIRv) reflected positive biodiversity effects on productivity, as expected from the literature. In contrast, traditional taxonomic α-diversity indices were generally not selected as relevant predictors of the ecosystem functional properties. Yet, β-diversity strongly contributed to the prediction of carbon use efficiency, surface conductance, and water use efficiency. We also found that the RaoQNIRv is less affected by issues of saturation and bare soil contribution compared to RaoQNDVI. We show that spectral heterogeneity based on remotely sensed NIRv holds the potential for globally characterizing the biodiversity-ecosystem functioning relationship (BEF). While systematic measurements of taxonomic diversity co-located at biogeochemical measurement stations could reduce the uncertainty surrounding the BEF relationship at whole-ecosystem scale, remotely- sensed metrics characterizing important functional and structural diversity aspects of the landscape will be crucial for continuous spatiotemporal monitoring of biodiversity with relevant implications for ecosystem services to humankind.
Local structure of homogeneous 𝐴𝑁𝑅-spaces
Authors: Valov Vesko
Published: October 2024

We investigate to what extend finite-dimensional homogeneous locally compact

A
N
R

ANR

-spaces have common properties with topological manifolds. Specially, the local structure of homogeneous

A
N
R

ANR

-spaces is described. Using that description, we provide a positive solution of the problem whether every finite-dimensional homogeneous metric

A
N
R

ANR

-compactum

X
X

is dimensionally full-valued, i.e.

dim
⁡
X
×
Y
=
dim
⁡
X
+
dim
⁡
Y

\dim X\times Y=\dim X+\dim Y

for any metric compactum 

Y
Y

.
Light Synth
Authors: Edstrom Brent
Published: October 2024

This chapter provides an overview of Light Synth. It starts with an introduction to Teensy microcontrollers. These are programmed with the same Integrated Development Environment as Arduino microcontrollers. Moreover, PJRC offers the Audio System Design Tool, which provides a helpful visual design tool that makes it easy to instantiate and connect audio components in the Teensy Audio Library. The chapter explains that the Light Synth project demonstrates the combined power of Teensy microcontrollers, the Audio System Design Tool, and the Teensy Audio Library. It then describes how hands-on experimentation is the best way to develop fluency with a program language.
Creating a Synthesizer User Interface
Authors: Edstrom Brent
Published: October 2024

This chapter discusses how to create a synthesizer user interference. It elaborates on the development of a synthesizer interface that can be used to experiment with a variety of synthesis topologies. Essentially, the source code uses less than 200 lines of code to implement the interface. The chapter then provides an overview of pushbuttons, rotary encoders, OLED display, and programming concepts including arrays, references, and object pointers that form the basis of an extensible synthesizer interface. It explains that pin assignments for all switches and encoders are listed at the top of the source file, which will provide a useful vehicle for experimenting with menu systems and parameter manipulation.
Granular Synthesis
Authors: Edstrom Brent
Published: October 2024

This chapter elaborates on the key concepts surrounding granular synthesis. It explains that granular synthesis is a category of synthesis with a theoretical foundation developed by composer Iannis Xenakis in the 1950s. Two simple projects that utilize sample-based granular concepts are a wavetable synthesizer with granular processing and a project that utilizes a USB connection for granular processing of a digital audio signal. The chapter notes that pitch shifting is one of the core attributes of granular synthesis’. It notes that granular processing provides unique opportunities for building custom instruments and sound-processing devices. Thus, granular synthesis provides many opportunities for sound design and composition.
Digital Signal Processing
Authors: Edstrom Brent
Published: October 2024

This chapter cites that audio signals can be processed on the Teensy platform in the form of digital signal processing (DSP). Unlike the expensive analog processors of yore, Teensy microcontrollers can do the job with better fidelity and for a modest cost. The Teensy platform allows the developing of unique processing units that can function as a component of a Eurorack setup, live rig, or guitar effects pedal. The chapter elaborates on the use of two DSPs from the Teensy Audio Library and the creation of two custom DSPs that are not currently available in the library. It also mentions that advanced users can roll their DSPs, opening the door to many possibilities for custom effects.
Building Eurorack Modules
Authors: Edstrom Brent
Published: October 2024

This chapter focuses on the stripboard as part of building Eurorack modules. Due to the wide variety of modules and potential for original creations built around microcontrollers and other technologies, Eurorack provides a modular framework with a vast potential for creative expression, expansion, and adaptation. Although the design concepts are applied to an analog project, core concepts apply to the embedded microcontroller projects. The chapter also provides an overview of the Eurorack format including dimensions, mounting, and other design considerations. It explains that building custom Eurorack modules using thru-hole components and stripboard fits with the DIY ethos of the platform.
Building a Eurorack Effects Unit
Authors: Edstrom Brent
Published: October 2024

This chapter considers how to build a Eurorack Effects Unit. The Eurorack Effects Unit is a relatively simple project that combines the power and audio circuits with concepts from Digital Signal Processing. Essentially, the unit takes a mono audio signal and provides four effects that are selected via a tactile switch. The Eurorack Audio Effects illustrates a capable Eurorack module that is fun to use and relatively inexpensive to build. The chapter explains the unit’s features might include an OLED for program selection, stereo processing, or multiple effects processing. It notes that the project can be constructed on a solderless breadboard, Gerber files, BOM, and other resources found on the OUP website.
Building Eurosynth
Authors: Edstrom Brent
Published: October 2024

This chapter details how to build a Eurosynth. It explains that a Eurosynth is a fun and powerful frequency-modulation synthesizer built on concepts. The interface of Eurosynth would be well-suited to other forms of music synthesis, which also includes enhancements like jacks for MIDI input, menu items for patch storage, or other features. The chapter considers custom Eurorack modules and design strategies that apply to a wide range of DIY projects. It explains that regular practice and experimentation allow the concepts of microcontrollers and Eurosynth to be more comfortable and enable the building of new instruments suited for a particular style of music making.
Clinicopathologic features and prognosis of steatohepatitic hepatocellular carcinoma based on varying cutoffs of tumoral steatohepatitic changes
Authors: Zhang Tao , Niu Na , Taddei Tamar , Jain Dhanpat , Zhang Xuchen
Published: October 2024

Objectives

Steatohepatitic hepatocellular carcinoma (SH-HCC) is currently recognized as a distinct histologic subtype of HCC. The prognosis and specific criteria for determining the amount of steatohepatitis required to define SH-HCC are still unclear.

Methods

After excluding all recognized HCC subtypes from 505 HCC cases (2010-2019), the remaining cases were categorized as conventional HCC (CV-HCC) (n = 223). The cases classified as SH-HCC (n = 171) were further divided into groups based on the percentage of steatohepatitis: 5% or more, 30% or more, and 50% or more.

Results

Hepatitis C virus infection was the predominant underlying liver disease in both the CV-HCC and SH-HCC groups. Metabolic dysfunction-associated steatotic liver disease (formerly nonalcoholic fatty liver disease) was more prevalent in all cases of SH-HCC with different steatohepatitic cutoffs than in cases of CV-HCC. There were no differences in the stage of fibrosis of the background liver between the CV-HCC and SH-HCC groups. SH-HCC with different cutoffs exhibited a notable increase in the presence of glycogenated nuclei, Mallory-Denk bodies, and hyaline globules in tumor cells. Survival analysis did not reveal substantial differences in overall survival between the CV-HCC and SH-HCC groups and among patients with SH-HCC with different steatohepatitis cutoffs.

Conclusions

The degree of intratumoral steatohepatitis in patients with SH-HCC does not appear to be a notable prognostic factor. The presence of steatohepatitis in the tumor is better recognized as 1 of the histopathologic patterns of HCC.