bluuebunny/crossref_metadata_2025_split huggingface dataset:
The thylakoid phosphatase TEF8 is involved in state transition and high light stress resistance in Chlamydomonas
Authors: Dong Jie , Hou Jinrong , Yao Qiang , Wang Baoxiang , Wang Jingyi , Shen Xuan , Lai Ke , Ge Haitao , Wang Yingchun , Xu Min , Fu Aigen , Wang Fei 
Published: October 2024

SUMMARYThe sophisticated regulation of state transition is required to maintain optimal photosynthetic performance under fluctuating light condition, through balancing the absorbed light energy between photosystem II and photosystem I. This exquisite process incorporates phosphorylation and dephosphorylation of light‐harvesting complexes and PSII core subunits, accomplished by thylakoid membrane‐localized kinases and phosphatases that have not been fully identified. In this study, one Chlamydomonas high light response gene, THYLAKOID ENRICHED FRACTION 8 (TEF8), was characterized. The Chlamydomonas tef8 mutant showed high light sensitivity and defective state transition. The enzymatic activity assays showed that TEF8 is a bona fide phosphatase localized in thylakoid membranes. Biochemical assays, including BN‐PAGE, pull‐down, and phosphopeptide mass spectrometry, proved that TEF8 associates with photosystem II and is involved in the dephosphorylation of D2 and CP29 subunits during state 2 to state 1 transition. Taken together, our results identified TEF8 as a thylakoid phosphatase with multiple dephosphorylation targets on photosystem II, and provide new insight into the regulatory mechanism of state transition and high light resistance in Chlamydomonas.
Influence of Ultrasonic Surface Rolling on the Tensile and Fatigue Properties of Laser-Cladding-Repaired 300M Steel Components
Authors: Cong Jiahui , Zhang Zhichao , Xing Xinyuan , Zhou Song , Gao Shoulong , Liu Zhuo 
Published: October 2024

Abstract
Herein, to address the issue of decreased tensile and fatigue performances observed in 300M steel scratched parts after laser-cladding repairing, an ultrasonic surface rolling process (USRP) was employed to enhance the strength of the laser-cladding-repaired (LCR) samples. Results indicated that USRP led to the formation of a strengthening layer on the surface of the samples. In the parent material area, the thickness of the strengthening layer was 180 μm, while in the cladding area, it was 35 μm. The superficial microhardness increased by 11.6% in the parent material area and by 5.0% in the cladding area. Furthermore, the surface residual stress transitioned from tensile to compressive stress, reaching a maximum of 1169.9 MPa. Improvements were observed in the tensile performance, as evidenced by a reduction in the length of the tearing ridge in the fracture morphology. In addition, the fatigue life considerably increased, initially increasing and then decreasing as the number of rolling passes increased. After four cycles of USRP, the fatigue life of the samples was the highest, which was about 18.4 times that of an unprocessed sample. The origin location of cracks shifted from the surface to the interior of the samples. This shift was accompanied by a decrease in the instantaneous fracture area and the emergence of additional secondary cracks. These experimental results demonstrate that USRP is an effective technique for improving the tensile and fatigue performances of LCR 300M steel samples.
Numerical Study of an Axial Piston Pump: Prediction Method of Flow Ripple Based on Digital Twin
Authors: Dong Chang , Tao Jianfeng , Sun Hao , Liu Chengliang 
Published: October 2024

Abstract
The flow and pressure ripple is generated by positive displacement pumps in the hydraulic circuit. Indirectly measuring flow ripple is complicated and impractical due to the complexity of the pipeline in practical systems and modeling uncertainty in model-based prediction methods. To address this problem, our research introduces an innovative approach utilizing digital twin technology for accurately predicting the flow ripple in axial piston pumps. The proposed method reduces modeling uncertainty by only including the pump model and a small part of the pipeline to the pressure sensor as the digital twin model. The measured pressure ripple signal from the pressure sensor is used as the boundary condition for the digital twin model. The effectiveness of this method is verified through numerical experiment. In these, we can easily obtained real flow ripple signals, demonstrating the practical applicability of our approach. The results are promising; with minimal modeling errors and no phase deviation, the predicted flow ripple closely aligns with the actual flow ripple observed in the experiments. This high degree of accuracy underscores the potential of our method in real-world applications. Furthermore, two soft solutions without an angle encoder installed at the shaft are proposed to find the phase-matching digital twin model.
Reduced-Order Discharge Area Surrogate Model of Claw-Shaped Notch Hydraulic Spool Valve
Authors: Zhang Yuhang , Ding Beichen , Yan Guishan , Ai Chao 
Published: October 2024

Abstract
The non-road mobile machinery, e.g., loader and tractor, is in urgent demand for energy conservation. As the core element of the non-road mobile machinery, the hydraulic spool valve has a noticeable pressure drop across the valve port under the condition of high pressure and great flow rate, especially with high-order notches, which causes large pump energy losses through heat dissipation. At present, lacking relevant studies of the coupling relationship between high-order notch structure and pressure drop leads to design challenges in optimizing notch matching scheme. To obtain in-depth understanding of the high-order notch optimization problem, this paper introduces a reduced-order discharge area surrogate model (RO-DASM) for claw-shaped notch (CSN) hydraulic spool valves based on computational fluid dynamics (CFD) analysis and Kriging model. This RO-DASM model is used exclusively to predict the flow rate-pressure drop (FR-PD) characteristics of the CSN hydraulic spool valve under the ultimate saturation flow rate (USFR) condition. CFD results indicate that the raised RO-DASM model achieves a credible forecast for pressure drop with an average relative deviation below 5% under the flow rate of 250, 350, and 450 L/min. The suggested model realizes the approximate expression of the CSN effectively and may be operated to various types of high-order notches flexiblely.
Fault Diagnosis of Pump Rotor-Bearing System Based on Frequency Temporal Series Graph Under Time-Varying Speed Conditions
Authors: Sun Sichao , Xia Xinyu , Yang Jiale , Zhou Hua 
Published: October 2024

Abstract
The pump serves as crucial power component in the hydraulic system. In the actual working process, it often runs in time-varying speed conditions such as startup, shutdown, acceleration, and deceleration, which makes the rotor-bearing system in the pump often work in an unstable environment and prone to failure. Most of the existing fault diagnosis researches are based on vibration signals. However, variations in rotational speed over time will also induce changes in vibration signal, which will cover the signal change caused by the fault of the system itself, resulting in confusion of signal characteristics and misjudgment of fault diagnosis. To perform precise fault diagnosis under time-varying speed conditions, a diagnosis method based on Frequency Temporal Series (FTS) graph is proposed. The time domain vibration signal is converted into the frequency domain signal by Fast Fourier Transform (FFT). The frequency values corresponding to the top k maximum amplitudes in the spectrum are selected as the node features, and the nodes are connected in chronological order through edges. The fault signal is constructed as the FTS graphs to map the time-varying fault information. Subsequently, a synchronous extraction model of spatiotemporal information is built, and the fault feature information embedded in graph nodes and the time dependence information among internal nodes of the graph are extracted at the same time to generate multi-scale fusion features. Finally, the fully connected and Softmax layers are employed as the classifier to categorize the multi-scale fusion features that have been extracted spatiotemporal information. Through experiments under time-varying speed conditions, it is verified that the proposed method can effectively identify the speed change during the operation of the system. The diagnostic accuracy reaches 99.17 %, outperforming other deep learning diagnostic methods.
Model Predictive Speed Control of a Digital Hydraulic Drive
Authors: Darnet Justin , Bideaux Éric , Trégouët Jean-François , Brunel Yohann 
Published: October 2024

Abstract
Model Predictive Control (MPC) strategies have already been successfully studied for digital hydraulics, especially to control the torque of digital hydraulic drives and the pressure of digital hydraulic transmissions. A great improvement of the efficiency was appreciated, at the expense of a large computational time. This paper proposes a novel approach of the MPC which aims at controlling the rotational speed of a digital hydraulic motor. The new cost function that is introduced in this paper enables the motor performance to be balanced between precision and energetic efficiency. This algorithm is then compared to another control strategy which allows as well to regulate the rotational speed of the motor very accurately, using the torque as intermediate variable instead of the motor displacement. The performance of both control laws are illustrated in simulation.
Design of Digital Displacement Pump Systems With Multiple Pumps
Authors: Wiens Travis , Schmidt Mitchell , Williamson Chris 
Published: October 2024

Abstract
Digital Displacement Pumps (DDPs) are hydraulic pumps which operate on the concept of enabling or disabling individual pistons of a radial piston pump. This allows for the combination of the high efficiency of radial piston designs with the flow control capability of a variable displacement design. In the most efficient mode, where each piston is fully enabled or disabled for an entire stroke of the piston, this results in a pulsing flow at the pump outlet. In some cases, this can result in undesirable levels of pressure pulsation with associated noise, vibration, and harshness. In previous work it has been shown that the design of the hose or piping immediately downstream of the pump can have significant effects on this pressure ripple. In this paper we expand this work to systems with two or more pumps in parallel. We present results comparing “star” and “rail” connection configurations and study the effects of line lengths and stiffness on generated pressure ripple. Simulation results are used to develop simple equations approximating resonance frequencies. Finally, we present guidelines for design of multi-pump DDP systems.
Optimization of Integrated High-Speed On/Off Valve Aligned With Voltage Control Strategies for Enhanced Dynamic Performance in Digital Hydraulic Systems
Authors: Huang Shuai , Xu HaoCheng , Lin Ye , Pan Feng , Zhou Hua 
Published: October 2024

Abstract
The high-speed on/off valve (HSV) is the core component of a digital hydraulic system. Current research mainly focuses on single coil spool-type HSVs, with limited investigation into coil optimization for multi-coil integrated HSVs. Developing high-performance HSVs with integrated multi-coils presents ongoing challenges, particularly in achieving low temperature rise, rapid response, and controllability. To address these challenges, this study proposes an optimization method for the integrated HSVs, harmonized with voltage control strategies to augment dynamic performance within digital valve systems. The investigation introduces a multi-coil integrated digital hydraulic valve and delves into the functional correlations among coil volume, temperature rise, and input power through both simulation and experimental methods. Leveraging multi-objective optimization techniques rooted in meta model of optimal prognosis (MOP) and evolutionary algorithm (EA), the design methodology refines the valve winding. The simulation results demonstrate that, firstly, under temperature rise constraints, coils designed with a four-voltage control strategy, compared to those developed based on single and three-voltage control strategies, will experience a reduction in opening time by 50% (from 2.0ms to 1.0ms) and 71.4% (from 3.5ms to 1.0ms), respectively, even if a four-voltage control strategy is applied subsequently. Secondly, if a single voltage control strategy is adopted for coils optimally designed based on three or four-voltage control strategies, the coil temperature may exceed the allowable limit, leading to coil burnout. Finally, regardless of the voltage control strategy used to obtain the coils, subsequent adoption of the three voltage control strategy results in the lowest coil temperature rise.
Development of an Intelligent Electric Motor-Driven Pump With High Energy Efficiency
Authors: Yang Bo , Pan Hong , Lu Yijie , Ling Zhenfei , Jiang Haoyi , Liu Hao , Ouyang Xiaoping , Yang Huayong 
Published: October 2024

Abstract
This paper proposes an intelligent electric motor-driven pump (EMP) with continuously variable pressure (CVP) configuration and develops a prototype, whose output power can match the load power, effectively improving the efficiency and reducing the heat generation of the aircraft pump source. The intelligent EMP prototype consists of a motor and an axial piston pump. The axial piston pump integrates a position sensor to monitor the position of the control cylinder of the swashplate, and uses a servo valve to control the swashplate, thereby controlling the outlet pressure of the pump. Furthermore, a pressure/displacement double closed-loop control strategy for the intelligent EMP prototype is proposed, which uses the displacement-loop as the inner-loop and the pressure-loop as the outer-loop to improve the control accuracy and dynamic responsiveness of the outlet oil pressure. Simulation and experimental results shown that, compared with the traditional pump source with pressure-compensated variable displacement EMP, the energy efficiency of the pump source with intelligent EMP is significantly improved by 21.3% and 20.8% under the same flight profile load spectrum, respectively.
Torque Ripple Minimization in a Variable Displacement Linkage Motor (VDLM) Through the Customization of Piston Trajectory
Authors: Herrera-Perez Martin , Boyce-Erickson Grey , Pozo-Palacios Jonatan , Voth John , Michael Paul , Van de Ven James D. 
Published: October 2024

Abstract
Hydraulic motors generate torque ripple, periodic fluctuations in output torque, adversely affecting performance for many applications. Traditional efforts to mitigate torque ripple have mainly addressed kinematic aspects by altering structural motor parameters, leaving dynamic torque ripple, influenced by fluid compressibility, less explored. This study introduces a novel approach to minimize torque ripple across different operating conditions in a Variable Displacement Linkage Motor (VDLM) by optimizing piston trajectory. Torque ripple was controlled by creating a custom piston trajectory defined by control points of a B-spline and tuning motor valve timing. The research employed kinematic and cylinder models to simulate the motion of the cam-linkage mechanism of the VDLM and the pressure dynamics in the piston chambers. The torque output and ripple of the motor were predicted through a simulation, and the motion of the pistons was optimized to minimize ripple. The VDLM torque ripple was reduced below 5% for a targeted corner condition and remained under 12% for other operating conditions, including fractional displacements of the motor. The optimized trajectory was compared to a baseline sinusoidal path, showing a simultaneous reduction in torque ripple at different operating conditions. Furthermore, the simulation results show good agreement when compared to experimental data obtained from a VDLM prototype constructed with an optimal piston trajectory. These results highlight the effectiveness of piston trajectory optimization in improving hydraulic motor performance, offering substantial benefits for applications requiring smooth output torque.
Experimental Investigation of Hydraulic Power Sharing Potential in a Dual Cylinder Electro-Hydraulic Variable-Speed Drive Network
Authors: van Binsbergen-Galán Mikkel , Videbæk Barbara , Vorbøl Hansen Kenneth , Schmidt Lasse 
Published: October 2024

Abstract
Variable-speed drive networks (VDN) constitute novel energy efficient drive architectures for hydraulic actuators used in industrial and mobile applications. VDN architectures control the power flows by the variable-speed control of electric machines which are driving hydraulic pump/motor units. These hydraulic units may be connected in various ways to the hydraulic actuators. Additionally, some actuator chambers may be hydraulically short circuited to allow free fluid flow between the connected chambers. This paper presents an experimental investigation of a dual cylinder VDN focusing on the hydraulic power sharing potential and energy efficiency. The VDN architecture is compared to an electro-hydraulic single axis cylinder drive system, also tested experimentally under equivalent load conditions. The applied VDN architecture includes three rotary pump/motor units and one hydraulic short circuit connection between the rod side chambers of the cylinders. The two hydraulic cylinders are made to follow a sinusoidal trajectory with varying phase shift. The more phase shift that is introduced between the cylinder trajectories, the more hydraulic power sharing is ascertained for the VDN architecture. This confirms the expectation that VDN architectures may be realized with lower power installations than electro-hydraulic single axis drive systems, and with higher energy efficiency when exploiting the hydraulic short circuit connection between cylinders.
A Comprehensive Approach for Predicting Remaining Useful Life in Electric External Gear Pumps
Authors: Borriello Pasquale , Frosina Emma , Tessicini Fabrizio , Senatore Adolfo 
Published: October 2024

Abstract
This paper presents a new methodology for predicting the Remaining Useful Life (RUL) of commercial electric pump units, aimed at overcoming limitations observed in existing approaches. In particular, it does not require a full-life test, its output is stochastic, it can be scaled to different operating conditions, and it can be used to guide design changes.
In the context of Prognosis and Health Management, having a model that correctly forecasts RUL can enable predictive maintenance-based strategies that can reduce costs and improve operability.
As known in the literature and observed by the experimental data collected in this study, although degradation is monotonic, its effect in terms of measured output is not. The proposed methodology leverages the Brownian model to predict the degradation path. The proposed framework incorporates Monte Carlo Simulations to provide a stochastic output with failure probabilities and survival plots. The model effectively captures the nonmonotonic consequences of degradation, particularly influenced by particle interactions, by accounting for randomness.
Furthermore, Computational Fluid Dynamics (CFD) simulations with a dispersed phase have been proven to identify erosion-prone areas and suggest design modifications to enhance pump robustness.
Combining experimental insights, stochastic modeling, and predictive simulations, this comprehensive approach establishes a robust foundation for RUL predictions and informed design enhancements in hydraulic pumps.
Comparison of Real-Time Pressure Rail Selection Algorithms for the Hybrid Hydraulic Electric Architecture: Case Study on a Track Loader
Authors: Wills Jackson , Li Perry Y. 
Published: October 2024

Abstract
The hybrid hydraulic electric architecture (HHEA) seeks to combine the high power/torque/force density of hydraulics with the efficiency of electric machines. A set of common pressure rails is used to provide a majority of the power and this power is modulated by small electric machines to provide precise control for the operator. The HHEA has been studied in previous work using off-line dynamic programming optimization to determine energy efficient pressure rail selections, but this approach requires drive cycle information apriori. A Lagrange multiplier method has also been investigated where a set of gains (Lagrange multipliers) are optimized off-line with the idea the these gains, once determined, could be used for real-time operation. In this work, three new real-time pressure rail selection algorithms that do not require future drive cycle information are investigated; greedy, torque minimizing, and thresholding. The greedy control is found to only use 1% more energy than the globally optimal dynamic programming solution; but a model of energy loss is required.
Semi-Empirical Model of the Leakage Flow in External Gear Pumps
Authors: Szwemin Paulina , Fiebig Wieslaw 
Published: October 2024

Abstract
Gear pumps are used in a wide range of applications because of their numerous advantages. To obtain the high pump efficiency, it is important to know and understand the relation between leakage losses and pump operating conditions. This paper presents a semi-empirical model that was developed to describe the volumetric losses in an external gear pump. It is based on the physical model proposed by Schlosser and contains not only loss terms that correspond to losses varying with pressure, viscosity, and density but also takes into account the effect of rotational speed, which is often ignored. The proposed leakage flow model is designed for external gear pumps and not for the entire group of positive displacement pumps, making it easier to adjust to specific cases. The proposed solution is concise and can be a useful tool for predicting volumetric losses in external gear pumps. It allows one to determine the values of these losses for various parameters of the working liquid and in a wide range of operating parameters of the pump.
Structure Matching Design of Lightweight CFRP/Metal-Lined Composite Hydraulic Cylinder
Authors: Shi Lifu , Yao Jing , Yu Tian , Xu Yuanzhi , Wan Xiaofei 
Published: October 2024

Abstract
Hydraulic cylinder is the component with the largest proportion of the weight moving with the host equipment in the hydraulic system. Its lightweight design can help reduce the equipment’s weight and improve the load, endurance and maneuvering performance, which has become the design development direction of hydraulic cylinder at present. Carbon Fiber Reinforced Polymer (CFRP), as a new lightweight material, has the advantages of higher specific stiffness/strength, lower thermal expansion coefficient, better corrosion resistance and fatigue resistance compared with aluminum alloy and high-strength steel materials. The composite manufacturing of hydraulic cylinder with CFRP and metal lining is the main technical means for the lightweight design of hydraulic cylinder at present. However, CFRP has the properties of material anisotropy on the macro level. How to make full use of this characteristic of CFRP and reasonably design the number and direction of fiber layering is the key problem to be solved in lightweight designing of the hydraulic cylinder. In this paper, a hydraulic cylinder served in an aviation actuator is lightweight designed by using the method of combining CFRP and aluminum alloy lining. According to the technology of finite element method, the effect of fiber layup sequence, direction, quantity and metal lining thickness on the performance of composite hydraulic cylinder is studied. The structure design method of the metal lining and the CFRP in the composite hydraulic cylinder are developed, and the effect of 55% weight reduction of the hydraulic cylinder is realized.