bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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

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

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

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

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

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

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

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.
Flow Ripple Reduction of Balanced Vane Pump for Variable Speed Drive Control in an Electric Mobile Machine
Authors: Wang Jiajia , Wang Feng , Xu Bing
Published: October 2024

The powertrain electrification of mobile machines is an effective method to reduce emissions and increase energy savings. Variable speed drive (VSD), has emerged as a more efficient and compact alternative for the electrified powertrain architectures. Existing vane pump technology, represented by Parker T7 Series and well-known as lower flow ripple and less noise comparing to piston pumps and gear pumps, is a promising choice for the VSD system. However, the limited performance of the balanced vane pump at low speeds hinders its further adoption. Therefore, the flow ripple characteristics of a balanced vane pump are studied across the full speed range, focusing specifically on speeds below 600 rpm. A lumped parameter model is proposed and implemented in MATLAB without relying on the computationally burdensome CFD approach. This model considers the interactions between vane radial motion and chamber pressure dynamics. Based on this model, the causes of flow ripple under low-speed conditions are analyzed. The results demonstrate that optimizing the structural parameters of the triangle groove can effectively reduce flow ripple under low-speed condition.
Sliding Mode Variable Structure Position Control for a Small-Scale Double-Cylinder Hydrostatic Actuation System
Authors: Peng Yanlin , Wang Bin
Published: October 2024

Small-scale two-cylinder hydrostatic actuator offers a unique advantage in narrow space operations because of its compact structure and flexible connection. However, factors such as long, thin hoses and leakage introduce significant nonlinearity into the position control system. To address these concerns and enhance both position tracking and anti-jamming capabilities, we propose a sliding mode control method with a variable structure. By implementing this control method, we aim to enhance the system capability to accurately track the desired positions, mitigating any disturbance caused by external loads effectively. Modeling and simulation of the entire system adopting this controller has been conducted to assess its performance under typical conditions. For step and sine commands without loads, the system using SMC exhibits higher accuracy and better dynamic performance compared to system using traditional PID controllers. The simulations demonstrate that the proposed method has excellent steady-state and dynamic effects on the actuator’s position control. Although there is not enough advantage in the smoothness of the displacement response, the system adopting the SMC method exhibits greater anti-jamming capabilities. In comparison to traditional PID control, the proposed method contributes to faster response and improved robustness under external disturbance.
Efficient electroporation in primary cells with PEDOT:PSS electrodes
Authors: Gharia Asmaysinh A. , Bradfield Clinton J. , Jenkins Elise P. W. , Fraser Iain D. C. , Malliaras George G.
Published: October 2024

Precise and efficient delivery of macromolecules into cells enhances basic biology research and therapeutic applications in cell therapies, drug delivery, and personalized medicine. While pulsed electric field electroporation effectively permeabilizes cell membranes to deliver payloads without the need for toxic chemical or viral transduction agents, conventional bulk electroporation devices face major challenges with cell viability and heterogeneity due to variations in fields generated across cells and electrochemistry at the electrode-electrolyte interface. Here, we introduce the use of microfabricated electrodes based on the conducting polymer poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS), which substantially increases cell viability and transfection efficiency. As a proof of concept, we demonstrate the enhanced delivery of Cas9 protein, guide RNA, and plasmid DNA into cell lines and primary cells. This use of PEDOT:PSS enables rapid modification of difficult-to-transfect cell types to accelerate their study and use as therapeutic platforms.
Temporal regulation of gene expression through integration of p53 dynamics and modifications
Authors: Lu Dan , Faizi Marjan , Drown Bryon , Simerzin Alina , François Joshua , Bradshaw Gary , Kelleher Neil , Jambhekar Ashwini , Gunawardena Jeremy , Lahav Galit
Published: October 2024

The master regulator of the DNA damage response, the transcription factor p53, orchestrates multiple downstream responses and coordinates repair processes. In response to double-strand DNA breaks, p53 exhibits pulses of expression, but how it achieves temporal coordination of downstream responses remains unclear. Here, we show that p53’s posttranslational modification state is altered between its first and second pulses of expression. We show that acetylations at two sites, K373 and K382, were reduced in the second pulse, and these acetylations differentially affected p53 target genes, resulting in changes in gene expression programs over time. This interplay between dynamics and modification may offer a strategy for cellular hubs like p53 to temporally organize multiple processes in individual cells.
Genesis of high-grade lode gold shoot dominated by ore fluid overprinting during a ductile-brittle shear event
Authors: Fu Lebing , Pirajno Franco , Wei Junhao , Chen Yong , Zhang Cheng , Li Aobing , Jiang Chunwei , Cao Lei
Published: October 2024

Lode gold deposits hosted by ductile-brittle shear zones account for more than one-third of the world’s gold production. High-grade ore shoots from this type of deposit are the most critical exploration targets. The ore shoots can form through the post-depositional deformation of auriferous sulfides or overprinting of ore fluids accompanied by coupled dissolution-reprecipitation (CDR) reactions. However, the mechanism that dominates ore shoot genesis remains unknown, primarily due to the controversial single progressive or polyphase nature of ore-bearing shear zones. Here, we report on geological and geochemical analyses we conducted at the large Hetai goldfield, South China, to construct an accurate gold upgrading model for the formation of ore shoots. Stages 1–3 of mineralization at Hetai show features typical of ductile shearing, while Stage 4 is characterized by quartz-sulfide veinlets in brittle fractures. 40Ar/39Ar ages of ca. 184 Ma and 157 Ma for the mineralization of stages 1 and 4 overlap with the regionally dextral ductile-brittle shear that occurred during ca. 210–162 Ma. Thus, the gold event at Hetai should have been controlled by a single progressive ductile-brittle shear episode, rather than polyphase structural events. The auriferous fluids at Hetai precipitated minor invisible gold in pyrites (mean 0.173 ppm) produced during stages 1–4 through fluid-rock interaction. The systematic increase of elements Au, As, Sb, Bi, Ag, and Cu and δ34S values in ductile-deformed pyrites from stages 1–3 indicate that early invisible gold upgrading should be the result of the post-depositional remobilization of auriferous sulfides during the long-lived ductile-brittle transition. Cataclastic pyrites hosting invisible gold from Stage 4 have zoned and porous mantles with elevated invisible gold (mean 0.503 ppm) and Sb, Bi, Pb, Co, Ni, and Ti contents. These pyrites are further replaced by chalcopyrite and pyrrhotite with increasing invisible gold, Co, and Ni contents. In addition, numerous visible native gold grains in Stage 4 are included in sulfides formed by replacement and develop along the microfractures and grain boundaries of these sulfides. We suggest the late invisible and visible gold upgrading events in Stage 4 can be attributed to the auriferous fluid superposition and subsequent replacement of pyrite via CDR reactions in a brittle regime. Therefore, the gold upgrading process at Hetai is jointly caused by the early remobilization induced by ductile-brittle deformation and the late ore fluid superposition with accompanying CDR reactions within a brittle domain. As the ore fluid superposition and CDR reactions in Stage 4 produce a significant amount of visible gold, they exert a first-order control on the genesis of ore shoots at Hetai. The refined model may be widely applicable to lode gold deposits elsewhere and can be used to identify regions with promising exploration targets.
Rb-Sr isochron method of sediment source fingerprinting reveals a fundamental shift in erosion in response to anthropogenic land use
Authors: Seal Dylan M. , Baxter Ethan F. , Snyder Noah P. , Cook Timothy L.
Published: October 2024

Human alterations to landscapes can greatly influence watershed-scale sedimentary processes; therefore, in this study, we test the viability of a novel Rb-Sr isotope and elemental geochemical method for fingerprinting the impacts of human land use on sediment provenance. We analyzed a ~1200-year sediment core record from Little Kennebago Lake, Maine, USA, that captures negligible anthropogenic activity pre-1900 CE, timber transport downstream during log drives (1900–1952 CE), and increased road construction and timber harvest (1952–2018 CE). 87Sr/86Sr data alone reveal several spikes, likely due to storm events, and variability but no systematic shift at the onset of logging. The pre-logging record Rb-Sr isotope data comprise an isochron corresponding to an age of 354 ± 16 Ma (two standard errors [2SE]; mean square of weighted deviates [MSWD] = 2.1, n = 33). None of the bedrock or glacial till sources that we analyzed fall along the pre-logging isochron, nor did any binary or ternary bulk rock mixtures. However, the linearity of all pre-logging samples and coincidence of the isochron age with Acadian metamorphism in the region suggests that sediment was derived from a single source in the undisturbed watershed, though that exact bedrock or glacial till source remains unclear.

The onset of logging coincides with a shift toward generally lower sediment Rb-Sr isotope ratios that are offset from the pre-logging isochron. This logging data forms a scattered pseudo-isochron with an apparent Carboniferous age of 322 ± 32 Ma (2SE; MSWD = 4.5, n = 10). No rocks of this age exist in the region. Therefore, we interpret this age to have no geologic meaning and instead reflect the introduction of new sediment sources due to logging. Logging also coincides with subtle changes in elemental geochemistry. The Big Island Pond Pluton underlies most of the northern part of the watershed and is the only catchment lithology capable of producing each geochemical change; therefore, we conclude that it was the primary new source of sediment introduced by logging. We found little variation in sediment geochemistry between the period of early log drives and later road expansion, suggesting that sediment provenance was constant once altered by the initial onset of logging, which could reflect the same source being tapped by activities in each period. We established a framework for interpreting bulk sediment Rb-Sr isotope ratios and demonstrated their viability for identifying shifts in human impacts on geomorphic processes. Our findings suggest that relative changes in sediment Rb-Sr isotope ratios are a promising tool for investigating changes to sedimentary processes not identifiable by other commonly used fingerprints and that the method should be further tested in a range of other natural and anthropogenic settings globally.
Sierra Negra, Galápagos: A resurgent-block basaltic caldera
Authors: Acocella V. , Galetto F. , Amelung F. , Aguaiza S.
Published: October 2024

Caldera resurgence is rare at mafic volcanoes. Here we consider the well-exposed resurgence at Sierra Negra caldera (Galápagos) to investigate how resurgence develops at a mafic system. Based on topographic and field analysis, the structure of the resurgence consists of an eastward-tilted block bounded by a fault-propagation fold activated by a steep inward-dipping reverse fault with dip decreasing toward the surface. Extension of the uplifted part of the reverse fault results from gravitational instability and is accommodated by horst-and-graben structures over a zone several hundred meters wide. Extension culminates in the main normal fault responsible for the inward tilt of the lava pile, forming a distinctive ridge. The resurgence results from spatially and temporally distinct unrest episodes, promoted by the shallow accumulation of large volumes of magma. Sierra Negra is the first documented example of piecemeal resurgence, as shown by the recent uplift episodes associated with eruptions in 2005 and 2018. The example of Sierra Negra suggests that the formation of resurgent blocks depends on the initial location of the feeding system, with non-centered feeding systems developing asymmetric (trapdoor) blocks. Finally, Sierra Negra demonstrates that mafic volcanoes without well-developed rift zones may promote resurgence when reaching a mature stage with significant amounts of cumulates, favoring shallow magma accumulation.
Eye movement desensitisation and reprocessing (EMDR) therapy in preterm children with selective mutism
Authors: Mesman Coby , Van Der Horst Iris , Spijker-Verkerk Fien , Bunt Jan Erik
Published: October 2024

Very preterm birth and treatment in neonatal intensive care cause stress early in life of the infant and may subsequently lead to psychological and behavioural traumas. Previous studies show positive outcomes of eye movement desensitisation and reprocessing (EMDR) therapy on trauma in children in general. This case report describes two girls that were born at very premature age (with birth weights of approximately 1000 g). They required intensive treatment in the neonatal intensive care. In early childhood, they presented with selective mutism (SM). We treated them with EMDR therapy because we hypothesised that trauma from the postnatal period had caused post-traumatic stress disorder. The EMDR therapy resulted in a long-lasting improvement in speech, social skills and communication. This is the first case report of development of SM in ex-premature infants that were treated with EMDR therapy in early childhood.
Using Hyperlink-Induced Topic Search Algorithm to Optimize Content Placement in Multimedia Content Delivery Network
Authors: Chen Jian-Bo , Chang Cheng-Hao
Published: October 2024

In the content delivery network (CDN) architecture, a large amount of multimedia is transmitted on the network, so the placement of CDN content will affect the network performance. How to place the content or find an appropriate location to add new content is a challenge in the CDN. In this paper, we use the hyperlink-induced topic search (HITS) algorithm to solve the problem of content placement. In the HITS algorithm, each domain of the CDN has two values: Authority and Hub. A domain with a higher authority value means that more traffic flows through this domain; a domain with a higher hub value means that more requests come from this domain. We use these two values to find the appropriate location for content placement. The experimental results show that the HITS algorithm has a shorter response time than other methods.
A Rubber-Embedded Subwavelength Seismic Metamaterial with a Wide Low-Frequency Bandgap
Authors: Zhang Kai , Cai Yimiao , Liu Xiangbing , Qi Liyuan , Yu Jiang , Deng Zichen
Published: October 2024

This study introduces a novel underground subwavelength seismic metamaterial (SM) designed to attenuate ultra-low-frequency surface waves. The SM comprises a three-component column featuring rubber embedded within a steel resonator. Through calculations utilizing the Bloch theorem and the sound cone method, we investigate the dispersion relations and vibration modes of three distinct SM configurations. Our proposed rubber-embedded SM exhibits a wide bandgap (BG) and effectively attenuates surface Rayleigh waves within the frequency ranges of 1.19–1.31[Formula: see text]Hz and 1.41–20[Formula: see text]Hz, respectively. We elucidate the mechanism behind BG formation by analyzing vibration modes. Additionally, through numerical simulations in both frequency and time domains, we validate the attenuation capabilities of the SM system within the BG and observe the deflection phenomena of surface waves. We further simulate seismic wave propagation within the SMs. Comparative analysis of two-dimensional building frames, with and without SM protection, under realistic seismic waves demonstrates significant vibration attenuation and structural protection provided by SMs. We explore the impact of geometric and material parameters, as well as the number of SM layers, on BG frequency range, designing an optimal SM model with the widest BG. Finally, we calculate transmission spectra for two- and three-dimensional subwavelength SMs and evaluate their efficacy in Rayleigh wave attenuation.
Operational Adaptability Improvement of High-Speed Trains Through Multi-Objective Control on Carbody Lateral Vibration
Authors: Wang Qunsheng , Du Wanliang , Jiang Xuesong , Zeng Jing , Wei Lai , Peng Xinyu
Published: October 2024

To improve the operational adaptability of high-speed trains, a control method is proposed to mitigate carbody lateral vibration by leveraging the dynamic vibration absorption effect of multi-suspended equipment. A comprehensive analysis of five typical wheel/rail contact relationships, closely related to vehicle operational status in the long-term service, is conducted and incorporated into the established rigid-flexible coupling dynamic model. Based on the proposed improved niche genetic algorithm (INGA), an objective function, which holistically assesses the vibration of the carbody and suspended equipment, is constructed to undertake the optimization analysis. The results show that the dynamic vibration absorption effect of the suspended equipment proves effective in controlling carbody lateral vibration, thereby enhancing operational adaptability. However, the improvement in vehicle performance varies under different operating conditions, influenced by the competitive relationship between multiple control objectives. While carbody lateral vibration performance could be further improved without considering equipment vibration tolerance, such improvements are limited, indicating that it is reasonable and necessary to consider equipment vibration tolerance in the research of carbody vibration control. This study furnishes valuable insights for improving the adaptability of high-speed train operations and provides ideas for further research on carbody vibration control using the suspended equipment.
Geometrically Nonlinear Vibration of Sandwich Shallow Shells with Auxetic Honeycomb Core Under Periodic/Impulsive Pressure
Authors: Li Zhengzhe , Zhong Rui , Wang Qingshang , Qin Bin
Published: October 2024

This paper presents the nonlinear vibration analysis of a sandwich shallow shell with a honeycomb core and functionally graded graphene-reinforced skins (HCFG-GRCF) under blast load, where the core layer is composed of negative Poisson’s ratio material and the three kinds of graphene distribution patterns are considered for structural face layer. First, the material properties of functionally graded graphene platelet reinforced composite (FG-GRC) are calculated using the extended Halpin–Tsai model. Based on the First-order shear deformation theory (FSDT) along with von-Karman nonlinearity, the energy function of the shallow shells is derived. Then the direct iterative method and Newton–Raphson method are, respectively, adopted to solve the nonlinear free vibration and dynamic response in the temporal domain. The applicability and accuracy of the proposed dynamic model are verified by comparing the present results with literature solutions and Finite Element Method (FEM) results. In addition, the effects of temperature, graphene fraction, thickness ratio of core to face thickness, honeycomb cell inclined angle and boundary conditions on the dynamic response of the shallow shells are systematically analyzed.
Study on the Vibration Behaviors and Reduction of Axially Moving Composite Cantilever Rectangular Plate with NES Under the Transverse External Excitation
Authors: Lu S. F. , Qiao H. L. , Zong D. , Bao C. C. , Zhang W. , Baoyin H. X. , Cao R. , Jiang Y.
Published: October 2024

The vibrational response amplitudes reduction is investigated for the axially moving composite cantilever rectangular (AM-CCR) laminated plate subjected to the transverse and parametric excitation by using the nonlinear energy sink (NES). Three different NES installed methods which are one NES, two NESs in series and two NESs in parallel are compared for the vibration attenuation of the AM-CCR laminated plate. For the dynamic model of the AM-CCR laminated plate with transverse and parametric excitation, using the first-order shear deformation theory, the von Karman large deformation theory, Hamilton’s principle, and the Galerkin discrete technique, the ordinary differential motion equations of the system are obtained. The pseudo frequencies and the nonlinear vibrational behaviors are depicted for the AM-CCR laminated plate. The nonlinear dynamic motion equations are established for the AM-CCR laminated plate with one NES, two NESs in series and two NESs in parallel are derived, respectively. The comparisons are given for vibrational response amplitude attenuation of the different locations in which the NES is placed on the end of the plate under the various retractable velocities. In addition, the influences of the number and the series and parallel connections of the NESs on the vibrational response reduction of the AM-CCR laminated plate are studied by the simulation method. When the AM-CCR laminated plate contracts, the scheme attached NESs in series has the optimal effect of the vibration reduction. When the AM-CCR laminated plate extends, the scheme with NESs in parallel has better effectiveness for the vibrational response reduction
Ensemble Bagging Model for Predicting Flexural Strength of Geopolymer Concrete
Authors: Onal Yasemin , Turhal Umit Cigdem , Ozodabas Aylin
Published: October 2024

Waste materials, such as fly ash and lime mortar, are used in the concrete industry to create an environmentally friendly environment. However, since the experimental studies will take time, it is necessary to predict the flexural strength (FS) and properties of Geopolymer concrete (GPC) using ensemble Learning (EL) algorithms in order to shorten the experimental work process and save money and time. In this study, a new ensemble the Bagging prediction model using gradient boosting regressor estimator is proposed to predict the FS of GPC using lime mortar. The performance of the proposed model was evaluated using the performance metrics [Formula: see text], RMSE, MSE, MAE, and MAPE. The proposed model was compared using the individual learning algorithms and validated using [Formula: see text]-fold cross-validation technique. From the SHAP plot obtained using the best proposed EL model BGR, ICE, and PDP analysis, it is seen that the blast furnace slag content has the most significant effect on the FS of GPC.
Safeguarding User-Centric Privacy in Smart Homes
Authors: Yu Keyang , Li Qi , Chen Dong , Hu Liting
Published: October 2024

Internet of Things (IoT) devices have been increasingly deployed in smart homes to automatically monitor and control their environments. Unfortunately, extensive recent research has shown that on-path external adversaries can infer and further fingerprint people’s sensitive private information by analyzing IoT network traffic traces. In addition, most recent approaches that aim to defend against these malicious IoT traffic analytics cannot adequately protect user privacy with reasonable traffic overhead. In particular, these approaches often did not consider practical traffic reshaping limitations, user daily routine permitting, and user privacy protection preference in their design. To address these issues, we design a new low-cost, open source user-centric defense system—PrivacyGuard—that enables people to regain the privacy leakage control of their IoT devices while still permitting sophisticated IoT data analytics that is necessary for smart home automation. In essence, our approach employs intelligent deep convolutional generative adversarial network assisted IoT device traffic signature learning, long short-term memory based artificial traffic signature injection, and partial traffic reshaping to obfuscate private information that can be observed in IoT device traffic traces. We evaluate PrivacyGuard using IoT network traffic traces of 31 IoT devices from five smart homes and buildings. We find that PrivacyGuard can effectively prevent a wide range of state-of-the-art adversarial machine learning and deep learning based user in-home activity inference and fingerprinting attacks and help users achieve the balance between their IoT data utility and privacy preserving.
A Clustering Approach to Unveil User Similarities in 6-DoF Extended Reality Applications
Authors: Rossi Silvia , Viola Irene , Toni Laura , Cesar Pablo
Published: October 2024

The advent in our daily life of Extended Reality (XR) technologies, such as Virtual and Augmented Reality, has led to the rise of user-centric systems, offering higher level of interaction and presence in virtual environments. In this context, understanding the actual interactivity of users is still an open challenge and a key step to enabling user-centric system. In this work, our goal is to construct an efficient clustering tool for 6 Degree-of-Freedom (DoF) navigation trajectories by extending the applicability of existing behavioural tool. Specifically, we first compare the navigation in 6-DoF with its 3-DoF counterpart, highlighting the main differences and novelties. Then, we investigate new metrics aimed at better modelling behavioural similarities between users in a 6-DoF system. More concretely, we define and compare 11 similarity metrics which are based on different
distance features
(
i.e.
, user positions in the 3D space, user viewing directions) and
distance measurements
(
i.e.
, Euclidean, Geodesic, angular distance). Our solutions are validated and tested on real navigation paths of users interacting with dynamic volumetric media in both 6-DoF Virtual Reality and Augmented Reality conditions. Results show that metrics based on both user position and viewing direction better perform in detecting user similarity while navigating in a 6-DoF system. Such easy-to-use but robust metrics allow us to answer a fundamental question for user-centric systems: “how do we detect if users look at the same content in 6-DoF?”, opening the gate to new solutions based on users interactivity, such as viewport prediction, live streaming services optimised based on users behaviour but also for user-based quality assessment methods.
How Changes in the Mean Latency, Jitter Amplitude, and Jitter Frequency Impact Target Acquisition Performance
Authors: Beech Sam , Stanton Fraser Danaë , Corston-Petrie Andy , Gower Andy P. , Gilchrist Iain D.
Published: October 2024

Interactive technologies require the user to frequently generate purposeful movements, where actions are guided towards targets. While delays between the movement onset and the corresponding update within the virtual space have been shown to impair target acquisition, the relative contribution of the individual latency parameters remains unclear. This article investigates how changes in latency, the moment-by-moment variability in the latency (jitter amplitude) and the rate of variability (jitter frequency), affect the speed and accuracy of target acquisition at different mean latencies. Experiment 1 explored changes in the mean latency and jitter amplitude. As the mean latency increased, we observed substantial impairments in completion time and accuracy, with increased variability in performance. There was also an interaction between the mean latency and jitter amplitude: although large jitter amplitudes caused a small completion time impairment, this effect decreased as the mean latency increased. Experiment 2 isolated the effect of the jitter by investigating changes in the jitter amplitude and jitter frequency at a fixed mean latency. Here, we observed completion time impairments from 67 ms amplitude and accuracy impairments from 134 ms amplitude. Like Experiment 1, the effect of the amplitude was small. Notably, we found no evidence that changes in the jitter frequency significantly influenced performance. Overall, increases in the mean latency contributed most to the impairment, disrupting acquisition speed and accuracy as it increased. Large jitter amplitudes also disrupted speed and accuracy, but this was a comparatively small effect that was mediated by the mean latency.
Interdigitated Electrodes (IDEs)-Supported Biosensing for Efficient Point-of-Care Applications
Authors: Kumar Vikas , Preeti Km. , Saini Vikram , Kaushik Ajeet , Sharma Sanjeev Kumar
Published: October 2024

Developing efficient micro-/nano-enabled sensing platforms based on the 5th and 6th generation is an escalating field where the data can be collected, transferred, and analyzed using AI and IoT systems in point-of-care (POC) situations. For personalized health, detecting low-concentration biomarkers requires highly efficient sensing electrodes. Interdigitated electrodes (IDEs)-based biosensors show promise due to their integration with microelectronics and ability for health monitoring. Systematic exploration of innovative designs, fabrication techniques, and surface chemistry is key to overcoming challenges and enabling efficient biosensing. This article explores IDEs’ potential in the early detection of diseases like cancer, COVID-19, and diabetes and discusses future directions.
Vascular chemerin from PVAT contributes to norepinephrine and serotonin-induced vasoconstriction and vascular stiffness in a sex-dependent manner
Authors: Wabel Emma A. , Krieger-Burke Teresa , Watts Stephanie W.
Published: October 2024

Chemerin1 receptor inhibition reduced norepinephrine (NE) and 5-HT-induced vasoconstriction in males. Genetic chemerin knockout (KO) resulted in lower pulse wave velocity in males. Differences in chemerin abundance in aorta perivascular adipose tissue (APVAT) may explain sex-dependent role of chemerin.
Recent advances associated with cardiometabolic remodeling in diabetes-induced heart failure
Authors: Sharma Gaurav , Chaurasia Shyam S. , Carlson Mark A. , Mishra Paras K.
Published: October 2024

Diabetes mellitus (DM) is characterized by chronic hyperglycemia, and despite intensive glycemic control, the risk of heart failure in patients with diabetes remains high. Diabetes-induced heart failure (DHF) presents a unique metabolic challenge, driven by significant alterations in cardiac substrate metabolism, including increased reliance on fatty acid oxidation, reduced glucose utilization, and impaired mitochondrial function. These metabolic alterations lead to oxidative stress, lipotoxicity, and energy deficits, contributing to the progression of heart failure. Emerging research has identified novel mechanisms involved in the metabolic remodeling of diabetic hearts, such as autophagy dysregulation, epigenetic modifications, polyamine regulation, and branched-chain amino acid (BCAA) metabolism. These processes exacerbate mitochondrial dysfunction and metabolic inflexibility, further impairing cardiac function. Therapeutic interventions targeting these pathways—such as enhancing glucose oxidation, modulating fatty acid metabolism, and optimizing ketone body utilization—show promise in restoring metabolic homeostasis and improving cardiac outcomes. This review explores the key molecular mechanisms driving metabolic remodeling in diabetic hearts, highlights advanced methodologies, and presents the latest therapeutic strategies for mitigating the progression of DHF. Understanding these emerging pathways offers new opportunities to develop targeted therapies that address the root metabolic causes of heart failure in diabetes.
Differential postnatal cardiovascular course of donor-recipient twins and associated pathophysiology—a cohort study
Authors: Ting Eugene , Teoh Mark , Sehgal Arvind
Published: October 2024

Evaluation for fetuses with twin-to-twin transfusion syndrome noted impaired cardiac function in recipients. Systematic data after birth are lacking. We noted greater ventricular dilatation, globularity, and hypertrophied interventricular septum in the recipient. Right ventricular contractility was reduced; differences between recipients-singletons had greater statistical significance compared with donors-singletons. The aorta had greater stiffness and lower distensibility in donors compared with recipients; the differences for arterial indices were statistically more significant with donors-singletons.
Haematological Profile and Antibiotic Resistance of Bacteria Responsible for Enteric Infections Isolated From Patients Suffering From Malaria and Enteric Infections on Consultation at the Dschang Regional Hospital
Authors: Ngai Roland Y. , Marbou Wiliane J. T. , Mbaveng Armelle T. , Kuete Victor
Published: October 2024

Malarial and bacterial coinfections in low‐income countries are a serious cause of morbidity and mortality, necessitating coadministration of antibiotics and antimalarials. This study investigated the relationship between malaria infection and bacterial drug resistance in malaria and nonmalaria patients on consultation at the Dschang Regional Hospital. A follow‐up study was carried out from October 2020 to December 2021 on 127 malaria and 174 nonmalaria patients having enteric infections. Clinical and haematological parameters were measured using standard methods. CD4 and CD8 cells were determined using flow cytometry. Enteric bacteria pathogens were isolated from stool, and antimicrobial and antimalarial profiles were determined using agar diffusion and microdilution methods, respectively. Significant reduction of RBCs, WBCs, CD4, CD8, granulocytes, monocytes and platelets was seen in coinfected patients compared to monoinfected participants (p ≤ 0.0491). E. coli was the main pathogenic bacteria isolated from the digestive tract of coinfected patients (40.63%) and monoinfected patients (59.37%). E. coli showed a high level of resistance to AMX (57.69%) and CDA (61.54%) in coinfected patients compared to 55.26% and 41.67%, respectively, in monoinfected patients. Quinine (53[50.00%]; 6[42.86%]) presented a minimal inhibitory concentration (MIC) of 32 μg/mL on the bacteria isolates from coinfected and monoinfected patients, respectively, while Artemether 89 (83.96%), Maloxine 5 (3.94%) and Surquina 250 (39.37%) presented a MIC of 64 μg/mL on bacterial isolates of coinfected and monoinfected patients. E. coli showed high resistance against AKI (45.93%), AMX (43.75%) and ERY (59.37%) in malaria patients who were under antimalarial drugs compared to malaria patients who were not under malaria drugs (29.68%, 34.37% and 32.81%, respectively). This study highlights that antimalarial drugs might certainly have an influence on the acquisition and emergence of bacterial resistance in the case of malaria bacterial coinfection, and therefore, adequate management and planning effective control programmes might certainly go a long way to reduce the rate of morbidity and mortality.