bluuebunny/crossref_metadata_2025 huggingface dataset:
The Association between High Preoperative MRI‐based Vertebral Bone Quality (VBQ) Score and Titanium Mesh Cage Subsidence after Anterior Cervical Corpectomy and Fusion
Authors: Li Qiujiang , Zhu Ce , Xia Qinghong , Yang Huiliang , Liu Limin , Feng Ganjun , Song Yueming
Published: November 2023

Objective

Recently, the MRI‐based vertebral bone quality (VBQ) score has been shown to correlate with Hounsfeld units (HU) value, dual‐energy X‐ray absorptiometry (DEXA) T‐score and predict osteoporotic fractures. Preoperative cervical HU value is an independent correlative factor for early titanium mesh cage (TMC) subsidence after anterior cervical corpectomy and fusion (ACCF). However, to date the direct association between cervical VBQ score and TMC subsidence has not been studied. This study aims to investigate the predictive effect of cervical VBQ score derived from sagittal non‐contrast‐enhanced T1‐weighted MRI on the early TMC subsidence after ACCF.

Methods

Patients who underwent one‐level ACCF from January 2016 to January 2020 were included. We retrospectively collected baseline data on age, sex, body mass index (BMI), disease type, level of surgery and radiology parameters. The cervical VBQ score was measured using preoperative non‐contrast‐enhanced T1‐weighted MRI. Univariate and multivariate logistic regression analysis were performed to screen the independent risk factors of TMC subsidence. The receiver operating characteristic (ROC) curve and area under curve (AUC) were performed to assess the predictive ability of TMC subsidence based on the cervical VBQ score. Spearman correlation analysis was used to determine the correlations between the cervical VBQ score and TMC subsidence.

Results

A total of 134 patients who underwent one‐level ACCF were included in this study, and 46 (34.33%) patients had TMC subsidence. Univariable analyses demonstrated that the age, TMC placement depth and VBQ score were associated with subsidence. The cervical VBQ score in the subsidence group was significantly higher than that in the no subsidence group (3.75 ± 0.45 vs. 3.20 ± 0.42, p < 0.001). The multivariate logistic regression analysis proved that the higher VBQ score (odds ratio[OR] = 13.563, 95% confidence interval [CI] 4.968 ‐ 37.031, p < 0.001) was the only variable that significantly predicted subsidence. Using a VBQ score cutoff value of 3.445, the cervical VBQ score yielded a sensitivity of 69.6% and a specificity of 85.2% with an AUC of 0.810 to differentiate patients with subsidence and with no subsidence.

Conclusion

Preoperative higher cervical VBQ score is an independent risk factor for TMC subsidence after ACCF. The cervical VBQ score may be a valuable tool for assisting in distinguishing the presence of TMC subsidence.
Unreliability of Serum‐ or Plasma‐based Assays of D‐dimer or Fibrin (Fibrinogen) Degradation Product for Diagnosing Periprosthetic Joint Infection: A Prospective Parallel Study
Authors: Xu Hong , Zhou Jing , Huang Qiang , Huang Zeyu , Xie Jinwei , Zhou Zongke
Published: November 2023

Objective

The ability of D‐dimer to diagnose periprosthetic joint infection (PJI) before revision hip or knee arthroplasty is still controversial, and the differences in diagnostic ability between serum‐ or plasma‐based assays of D‐dimer and fibrin (fibrinogen) degradation product (FDP) are uncertain. The prospective parallel study was performed to determine the ability of D‐dimer to diagnose PJI before revision hip or knee arthroplasty, and the differences in diagnostic ability between serum‐ or plasma‐based assays of D‐dimer and FDP.

Methods

Patients undergoing knee or hip arthroplasty at our institution were prospectively enrolled into the following groups: those without inflammatory diseases who were undergoing primary arthroplasty (“Prim” group), those with inflammatory arthritis who were undergoing primary arthroplasty (“Prim/Inflam”), those undergoing revision arthroplasty because of aseptic failure (“Rev/Asept”), or those undergoing revision arthroplasty because of PJI (“Rev/PJI”). The ability of preoperative levels of D‐dimer or FDP in serum or plasma to diagnose PJI in each group was assessed using areas under receiver operating characteristic curves (AUCs) and other diagnostic performance indicators. The diagnostic performance of these assays was compared with that of C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

Results

In the final analysis, Prim included 42 patients; Prim/Inflam, 40; Rev./Asept, 62; and Rev./PJI, 47. D‐dimer assays led to AUCs of 0.635 in serum and 0.573 in plasma, compared to 0.593 and 0.607 for FDP. Even in combination with CRP or ESR, these assays failed to perform as well as the combination of CRP and ESR for diagnosing PJI.

Conclusion

Levels of D‐dimer or FDP in serum or plasma, whether used alone or together with CRP or ESR, are unreliable for diagnosing PJI before revision arthroplasty.
New insight into highly efficient CSA@g‐C3N4 for photocatalytic oxidation of benzyl alcohol and thioanisole: NAEDS as a promoter of photoactivity under blue LED irradiation
Authors: Hosseini Saber , Azizi Najmedin
Published: November 2023

An open new perspective has been established toward synthesizing eco‐friendly CSA@g‐C3N4 employing surface engineering. The carbon nitride modified through camphorsulfonic acid was designed and developed in a category of the new generation of photocatalysts for the oxidation of benzyl alcohol and thioanisole in the existence of a natural deep eutectic solvent (NADES). In comparison with pure g‐C3N4, not only does CSA@g‐C3N4 exhibit an extraordinarily higher ability for harvesting visible light stemming from declining the recombination rate of electrons/holes dependent on PL results but it also reveals notable photocatalytic oxidation capability in the transformation of alcohols as well as thiols into relevant compounds. In addition, non‐metal compound (CSA) incorporation would result in considerably diminishing the energy band gap value from 2.8 to 2.28 eV to escalate the visible‐light absorption of g‐C3N4. While the conventional consensus implies that inherent properties of photocatalysts bring on high photoactivity, this study indicates that deploying choline chloride–urea deep eutectic solvent as an external factor plays the role of photoactivity accelerator. Furthermore, readily recycling and reusability can be achieved for the photocatalytic setup of CSA@g‐C3N4 ascribed to its heterogeneous nature with no drop in the photoactivity.
Natural deadwood hosts more diverse pioneering wood‐inhabiting fungal communities than restored deadwood
Authors: Saine Sonja , Penttilä Reijo , Furneaux Brendan , Monkhouse Norman , Zakharov Evgeny V. , Ovaskainen Otso , Abrego Nerea
Published: November 2023

Deadwood can be recreated as a forest restoration measure to increase the amount of deadwood and assist deadwood‐dependent biodiversity. While deadwood restoration is known to have an overall positive effect on associated species in the long term, it remains poorly understood how and when wood‐inhabiting organisms colonize different kinds of deadwood, which is essential for developing efficient restoration frameworks. In this study, we use DNA metabarcoding to compare wood‐inhabiting fungal communities between fresh naturally fallen spruce logs and spruce logs felled for restoration. The results show that although pioneering fungal community composition greatly differs between natural and felled logs, with natural logs hosting more species‐rich and heterogeneous communities, felled logs still hold a relatively high fungal diversity. Responses to log type carried a strong phylogenetic signal, and orders Polyporales and Hymenochaetales including most species of conservation concern were more likely to occur in natural than in felled logs. Furthermore, we found that log type was more important for rarely recorded than commonly recorded taxa, suggesting that rare species might be more specialized in their habitat requirements than the common ones. Overall, while restored deadwood can hold a high fungal diversity, the results underline that freshly felled logs do not mimic fresh natural logs. Deadwood restoration should focus not only on increasing the quantity of deadwood but also on the quality of thereof, and most importantly, retaining the existing natural deadwood rather than artificially downing trees.
Rebalancing social & personality psychology methods: The case for naturalistic observation
Authors: Robbins Megan L. , Jonnalagadda Pavani , Spahr Chandler M.
Published: November 2023

Though naturalistic observation methods are lauded for their utility, they are often neglected in social and personality psychology research. This paper describes evidence of the absence of naturalistic observation methods in our field, and some historical roots of this methodological imbalance in social/personality (SP) psychology. The paper then provides an overview of existing naturalistic observation methods relevant to SP psychology, describes various types of barriers to conducting such research, and concludes with recommendations for overcoming these barriers to produce a more well‐rounded science. It is time to rebalance SP psychological methods by valuing and investing in naturalistic observation research.
Language acquisition in the theological classroom: A case study in comprehensible input
Authors: Westengard Brandon L.
Published: November 2023

Languages have played a significant role in the shaping of theological and religious leaders. Historically consisting mostly of biblical and ancient languages, contemporary theological education includes the study of modern foreign languages for research and ministerial purposes. If written and spoken communication in a variety of languages is a foundational aspect of the theological classroom, why is it, then, that seminaries and theological institutions give little attention to theories and pedagogies of second language acquisition? This article seeks to expose theological educators to the most significant theory in the study of language pedagogy and provides a case study of a course taught to students in a seminary setting. In addition to scholarly studies, it relies on the influence of autodidactic polyglots, an indispensable source of experience and wisdom in the world of language acquisition. By improving practices around language instruction, the future of theological education can better engage with a multi‐cultural and global society.
A comparison of seven innovative robotic weeding systems and reference herbicide strategies in sugar beet (Beta vulgaris subsp. vulgaris L.) and rapeseed (Brassica napus L.)
Authors: Gerhards Roland , Risser Peter , Spaeth Michael , Saile Marcus , Peteinatos Gerassimos
Published: November 2023

More than 40 weeding robots have become commercially available, with most restricted to use in crops or fallow applications. The machines differ in their sensor systems for navigation and weed/crop detection, weeding tools and degree of automation. We tested seven robotic weeding systems in sugar beet and winter oil‐seed rape in 2021 and 2022 at two locations in Southwestern Germany. Weed and crop density and working rate were measured. Robots were evaluated based on weed control efficacy (WCE), crop stand loss (CL), herbicide savings and treatment costs. All robots reduced weed density at least equal to the standard herbicide treatment. Band‐spraying and inter‐row hoeing with RTK‐GPS guidance achieved 75%–83% herbicide savings. When hoeing and band spraying were applied simultaneously in one pass, WCE was much lower (66%) compared to the same treatments in two separate passes with 95% WCE. Hoeing robots Farmdroid‐FD20®, Farming Revolution‐W4® and KULTi‐Select® (+finger weeder) controlled 92%–94% of the weeds. The integration of Amazone spot spraying® into the FD20 inter‐row and intra‐row hoeing system did not further increase WCE. All treatments caused less than 5% CL except for the W4‐robot with 40% CL and the combination of conventional inter‐row hoeing and harrowing (21% CL). KULT‐Vision Control® inter‐row hoeing with the automatic hydraulic side‐shift control resulted in 80% WCE with only 2% CL. Due to the low driving speed of maximum 1 km h−1 of hoeing robots with in‐row elements, treatment costs were high at 555–804 € ha−1 compared to camera‐guided inter‐row hoeing at 221 € ha−1 and broadcast herbicide application at 307–383 € ha−1. Even though the costs of robotic weed management are still high, this study shows that robotic weeding has become a robust, and effective weed control method with great potential to save herbicides in arable and vegetable crops.
Utilizing Special Language in Street Crime Newsgathering in Indonesia
Authors: Darsono Dono , Sjuchro Dian Wardiana , Rustandi Ridwan , Muhaemin Enjang
Published: November 2023

This article describes the newsgathering process among the crime journalist community in West Java, which involves the use of special symbolic languages. Using the ethnographic method, the study was conducted to collect data related to the practice of using special language, especially how crime journalists interpret it and how it functions for their profession. The results have shown that special language is not only used in the newsgathering process but also in daily interactions with fellow community members and police officers as news sources. As a result, the special language used consists of both abstract and concrete symbols. Abstract symbols encompass verbal and nonverbal forms that are embodied in numeric, phonetic, and cosmic codes. Meanwhile, concrete symbols are related to how they dress and use equipment, and how all these attributes represent them as crime journalists. This is related to the functions of special language, namely as a means of distinguishing themselves from other journalist groups. In addition, this special language also serves as a form of identity manipulation, allowing them to take on the role of the police in information gathering.
Machine Learning Aided Numerical and Experimental Investigation of Hydrodynamic Performance in the Circulating Fluidized Bed Boiler
Authors: Mercy Vasan A. , Sridharan M. , Gopalakrishnan V. , Shiva Ranjani R. S.
Published: November 2023

This study attempts to illustrate the benefits of integrating the concepts of machine learning algorithms with the field of thermo-fluidic applications. The current work is aimed at identifying effective or significant hydrodynamic input parameters, which are capable of deriving full benefit of fluidization that could yield a better circulating fluidized bed (CFB) furnace design using the Apriori algorithm. For this, historical datasets from the literature are collected and pretreated based on the design under observation. Association analysis performed by this Apriori algorithm measures the comparative strength of parameters under consideration. Also, this algorithm is capable of identifying the right combinations of parameters that can produce maximum fluidization performance. The end results suggested by this Apriori algorithm are validated using the computational fluid dynamics package. For this, the transient behavior of a scaled-down (1:20) reactor model of a real-time industrial CFB boiler is simulated using ansys fluent 18.0. In specific, the effects of fluidizing velocities, inventory heights of the bed, and particle sizes recommended by the Apriori algorithm are investigated. Here, the effects are assessed in terms of volume fraction distribution and axial velocity profile distribution profiles. From the results of simulations, it was clearly found that 2 m/s inlet velocity produced good circulating fluidized bed patterns on a bed inventory height of 0.5 m for a mean particle size of 200 µm. The results obtained from the simulations are once again validated visually against snapshots obtained during real-time laboratory fluidization experimental runs. Among all the cases of comparisons, the best agreement is demonstrated by Apriori algorithm compared to the numerical and the experimentally obtained results. Also, it is found that the manual time taken to identify the right combinations of parameters is drastically reduced by this method compared to conventional optimization algorithm and trial error methods.
Aerothermal Performance Robustness and Reliability Analysis of Turbine Blade Squealer Tip With Film Cooling
Authors: Huang Ming , Zhang Kaiyuan , Li Zhigang , Li Jun
Published: November 2023

The uncertainty quantification in the turbine components' aerodynamic and heat transfer performances is widely considered to be the most challenging topic due to its intricate and nonlinear characteristics. This paper first proposes an efficient uncertainty quantification method based on an original parallel framework combining Polynomial Chaos Expansions (PCE) with two forms (stochastic response surface-based and Galerkin projection-based) and the Universal Kriging method. The rigorous mathematical tests are performed to verify the reliability and computational efficiency of the proposed method, and the results support that this method can dramatically reduce computational samples compared to the conventional PCE method while maintaining computational accuracy. Then, the genetic algorithm was introduced to establish an efficient uncertainty quantification framework, and it is applied to the aerothermal performance robustness investigation of the GE-E3 rotor blade tip with and without film cooling. Based on the findings of uncertainty quantification, the injection of cooling air drastically enhances the unstable tendency of the flow and thermal fields, resulting in the actual aerothermal performance of the squealer tip being much lower than that predicted by deterministic calculations. The setting of the film cooling, although effective in reducing the heat flux around the cooling holes, also induces more chaotic flow and thermal fields, leading to sharp heat flux fluctuations around the cooling holes. Finally, our novel reliability analysis algorithm, rooted in the quantification of uncertainty, corroborates the assertion that the introduction of coolant gas, while extending the operational longevity of turbine blades, confers only marginal improvements in the mitigation of lifespan variability. The comprehensive lifespan assessment elucidates that the mean operational longevity of the conventional squealer tip design stands at an estimated 16,169.44 h, accompanied by a standard deviation of 2,750.31 h. In stark contrast, the mean operational longevity of the squealer tip integrated with film cooling measures a significantly enhanced 17,035.17 h, exhibiting a standard deviation of 2,492.73 h. Consequently, the operational lifespan of the conventional squealer tip experiences a decrement of 10.17% in comparison to the anticipated mean lifespan, whereas the reduction for the film-cooled squealer tip registers at 5.36%.
A Model of Mass and Heat Transfer for Disc Temperature Prediction in Open Compressor Cavities
Authors: Nicholas Tom E. W. , Scobie James A. , Lock Gary D. , Tang Hui
Published: November 2023

Accurate prediction of heat transfer in compressor cavities is crucial to the design of efficient and reliable aircraft engines. The heat transfer affects the thermal expansion of the compressor rotor and, in turn, the tip clearance of the compressor blades. This article presents a novel, physically based predictive theoretical model of heat transfer and flow structure in an open compressor cavity, which can be used to accurately calculate disc temperatures. The radially higher region of the cavity is dominated by buoyancy effects created by the temperature difference between the hot mainstream flow and the axial throughflow used to cool the turbine. Strong interaction between the air in the cavity and this throughflow creates a mixing region at low radius. For a given geometry, the heat transfer and flow physics are governed by four parameters: the rotational Reynolds number Reϕ, the buoyancy parameter βΔT, the compressibility parameter χ, and the Rossby number Ro. The model quantifies both the buoyancy- and throughflow-induced mass and heat transfer, producing a reliable prediction of the disc and air temperatures. The model takes into account a twofold effect of the throughflow: being entrained into the cold radial plumes directly and creating a toroidal vortex in the radially lower region of the cavity. The exchange of mass between the cavity and throughflow is related to the mass flowrate in the radial plumes in the buoyancy-induced region, considering the effect of flow reversal at low Ro. The model is validated using data collected in the Bath compressor cavity rig and can be incorporated in engine design codes to robustly compute the thermal stress and expansion of the compressor rotor, contributing to more efficient engine designs.
A Novel Redacted Extended Kalman Filter and Fuzzy Logic-Based Technique for Measurement of State-of-Charge of Lithium-Ion Battery
Authors: Bera Chinmay , Mandal Rajib , Kumar Amitesh
Published: November 2023

This paper presents a novel technique based on an adaptive approach of redacted extended Kalman filter (REKF) assimilating fuzzy logic features for measuring the state-of-charge (SoC) of lithium-ion batteries. Accurately determining SoC is crucial for maximizing battery capacity and performance. However, existing extended Kalman filtering algorithms suffer from issues such as inadequate noise resistance and noise sensitivity, as well as difficulties in selecting the forgetting factor. The aforementioned REKF technique addresses these challenges adequately for accurate measurement of SoC. The proposed method involves establishing a Thevenin equivalent circuit model and using the recursive least squares with forgetting factor (RLSFF) to identify model parameters. Furthermore, an evaluation factor is established, and to adaptively adjust the value of the forgetting factor, fuzzy control is utilized, which enhances the extended Kalman filtering algorithm with noise adaptive algorithm features to estimate the SoC accurately. This modified algorithm considers the identification results from the parameter estimation step and executes them circularly to achieve precise SoC estimation. Results demonstrate that the proposed method has excellent robustness and estimation accuracy compared to other filtering algorithms, even under variable working conditions, including a wide range of state-of-health (SOH) and temperature. The proposed method is expected to enhance the performance of battery management systems for various applications.
A Highly Compact, Multi-Material, Fluid Powered Actuation System for MRI-Guided Surgical Intervention
Authors: Peters John E. , Grillo Abby M. , Esser Daniel S. , Garrow Sarah J. , Kumar Nithin S. , Ball Tyler , Naftel Robert , Englot Dario J. , Neimat Joseph , Grissom William A. , Webster Robert J. , Barth Eric J.
Published: November 2023

This paper presents an inherently safe, compact, 3D-printed, fluid-powered stepper actuation system enabling surgical precision within the demanding and confined space of a magnetic resonance imaging (MRI) scanner. The intense magnetic field and limited workspace of an MRI excludes the use of traditional, ferromagnetic robotics. Additionally, scanner image quality is sensitive to interference, creating a strict constraint on the electromagnetic and ferromagnetic signature of the actuator. While non-ferromagnetic, fluid powered actuators exist, they are often bulky and difficult to control. Using high resolution, material jetting technology, we’re able to 3D print small, standalone multi-material designs with variable rigidity. Leveraging these advances in additive manufacturing technology, we have developed a modular set of miniature flexible fluidic actuators (FFAs). These actuators are capable of translating, rotating, and gripping a slender rod and are inherently safe to valve, control, or pressure faults, due to the stepping sequence. Using a specific clinical application as a use case, we assembled these components into a highly compact needle steering system for MRI-guided neurosurgery. This two-degree-of-freedom actuation system is driven pneumatically, taking advantage of sterile, hospital instrument air and is electromagnetically transparent to the MRI scanner. In addition to detailing the actuator system design, this paper also demonstrates a robust, nonlinear control strategy for precision sub-step motion control. This paper reports the actuator system’s operating pressure and bandwidth, translational and rotational accuracy, and maximum force and torque capabilities.
Modelling of Pumps and Motors As Source Flow Ripple and Source Impedance
Authors: Johnston Nigel , Dumnov Daniil , Melling Jonathan
Published: November 2023

The fluid borne noise characteristics of hydraulic pumps and motors are commonly represented in the frequency domain using a source flow ripple spectrum in parallel with a source impedance spectrum. This is equivalent to Norton’s theorem for electrical sources in which the source is represented as a current source in parallel with a resistance or impedance. The validity of this representation is considered for two types of piston pump through simulation and for a third piston pump through experiment. It is shown that the Norton model of source flow ripple and source impedance is a reasonable approximation to the fluid-borne noise characteristics of positive displacement pumps. However for pumps in which fluid compression is a dominant feature in the source flow ripple, such as piston pumps, the source flow ripple varies somewhat with the system pressure ripple, and this causes significant problems with the Two Loads method, resulting in unrealistic source impedance measurements.
The Case for Replacement of Pilot Valves With Pilot Pumps in Hydraulic Control Systems
Authors: Wiens Travis
Published: November 2023

Traditionally, hydraulic servo power for high bandwidth primary stage actuation in electrohydraulic pumps and valves is provided by small pilot stage valves. These often operate in a pressure-control mode against a spring to effect position control of the main valve spool or pump swash plate. This paper presents the case for replacing these valves with small fixed-displacement, electronically speed-controlled pumps. Depending on the system, advantages can include more linear control, faster response, lower development and component cost, and higher energy efficiency.

This paper presents comparative analysis of this concept for two common cases: a two-stage spool valve, and an axial piston load sensing pump. The first demonstrates that for systems of comparable flow capacity a pump-controlled-pump system will respond faster than a valve controlled system due to supplying its maximum flow for the majority of the response, as opposed to a valve controlled system whose flow reduces as pressures equalize. This system also exhibits a more linear response, easing closed loop control design.

The second case study presents a pump flow control application, which demonstrates the pump-controlled-pump system can be more easily and safely designed using linearized control system analysis techniques. The linearized analysis correctly identifies the stability limits for the pump-controlled-pump, but dangerously overestimates the proportional gain limits for a valve-controlled system.
Novel Design of a General-Purpose In-Situ Tribology Test Chamber for Fluid Power Applications
Authors: Masia Antonio , Caponeri Giulio , Cetra Stefano , Shang Lizhi
Published: November 2023

The efficiency and reliability of hydrostatic pumps and motors are significantly affected by their tribological interfaces, which function as both a seal and a bearing. The performance of tribological interfaces is heavily influenced by their design parameters, including clearance, roughness, material, surface finishing, and thermal treatment, as well as the operating conditions, such as speed, load, temperature, and fluid characteristics. Experimental tribological tests of isolated lubricating interfaces for various designs and operating conditions can greatly assist pump and motor designers in addressing the increasing demand for highly efficient hydrostatic machines. The challenge of designing the experiment for the abovementioned purpose is to keep the isolated lubricating interface operating in a well-representative operating condition. This paper introduces and describes a novel general-purpose in-situ tribology test chamber for fluid power applications with the goal of conducting tribological tests of individual lubricating interfaces of different types of hydraulic units. The novel design of the test chamber is co-designed by Purdue researchers and Test Industry S.r.l. Its core element is the test chamber, which allows for testing the sample fully submerged in hydraulic oil. It provides the sample with the environmental condition necessary to replicate realistic operating conditions, such as load, pressure, rotation speed, and fluid temperature. This paper describes the definition of the test rig specifications, the test rig’s design architecture, hydraulic circuit, hydraulic system capability, and mechanical driveline. The general capabilities of the test rig, as well as its ability to investigate a wide range of lubricating interfaces by measuring the main tribological parameters such as friction, leakage, pressure/temperature distribution, and loading capability of hydrostatic machine tribological interfaces, are also described. The first experimental investigation will be conducted on a piston pump machine design to investigate the friction and leakage from each of its interfaces — piston/cylinder, block/valveplate, and slipper/swashplate separately at various operating conditions, including the speed at around zero rpm. The sensor parameters, sample design, and test results in terms of the overall frictional torque of the selected sample will be discussed.
Counteracting Centrifugal Forces on the Cups in a Floating Cup Pump
Authors: Achten Sef , Mommers Robin , Achten Jasper , Potma Jeroen , Achten Peter
Published: November 2023

Within hydraulic axial piston machines, critical components experience centrifugal forces, which can limit the performance of the actual machine. Often, this results in tipping of the cylinder block or barrel, causing friction in the barrel-port plate interface and affecting the efficiency and durability of the machine. In a hydraulic machine based on the floating cup technology, such as pumps, motors, and hydraulic transformers, the centrifugal force experienced by the cups is counteracted by the fixed pistons. The combined reaction forces on the cups cause a tipping torque on the barrel plate. Although a hydrostatic trust bearing can be used to compensate for such tipping, the effectiveness of the bearing depends on the pressure within the system and is limited in the amount of torque it can compensate for. This solution is sufficient for machines up to a certain size and a maximal rotational speed. However, if the machine requirements exceed these limits, a different solution is needed.

Ideally, the centrifugal forces on the cups are counteracted by the barrel plate, since it rotates around the same axis as the cups. This can be realized by introducing an opposite force using counterweights connected to the barrel plate. The centrifugal force on the counterweight is redirected via a lever to counteract the centrifugal force on the cup, minimizing the interaction between the cup and piston. As a result, the barrel plate tipping torque is diminished, decreasing the friction between the barrel plate and the port plate, which in turn results in an increase in efficiency and durability of the machine. The new solution also creates the opportunity to further increase the maximum rotational speed. This is especially important for electro-hydraulic actuators and hydraulic transformers.
Optimal Design of Cartridge Check Valve Control Unit in a Multi-Pump Hydraulic System
Authors: Xi Xiangshuo , Wang Qingfeng , Wang Tao
Published: November 2023

Multi-pump hydraulic systems have a wide range of applications requiring large flowrate. As a highly integrated component, the cartridge check valve (CCV) control unit has an important influence on the overall performance of multi-pump large-flowrate systems. It is a critical issue to design its parameters properly, for mismatched parameters may lead to poor performance or even accidents. On the one hand, it is challenging to implement accurate theoretical analysis due to strong nonlinearity and complexity. On the other hand, the implementation of optimal design using a trial-and-error approach is time-consuming and expensive. To solve these problems simultaneously, this work develops an automatic method to design the parameters of the CCV control unit based on the combination of numerical simulations and the nondominated sorting genetic algorithm III. The parameter discretization method based on probability has been proposed to improve the performance of the optimization algorithm. Both subsequent simulations and experimental results confirm that the performance indicators of the optimized hydraulic system such as backflow and response time have been significantly ameliorated compared to the original hydraulic system. In general, this work develops a time-saving and convenient method for parameter optimization of the CCV control unit, which can also serve as a reference for component design and selection in similar hydraulic systems.
An Analysis of a Multi-Pump System for Actuator Operation in Electric Mobile Machinery
Authors: Tozzi C. Gama Artur , Heybroek Kim , Ericson Liselott
Published: November 2023

This paper presents an analysis of a multi-pump solution for a hydraulic cylinder for application in mobile machinery with electric prime movers. The flexibility provided by using electric motors instead of an internal combustion engine allows for the design of alternative hydraulic architectures that remove the need for a centralized pumping system and support more direct control of individual components. This allows them to operate at a higher efficiency region to improve overall vehicle efficiency, leading to smaller batteries and shorter or less frequent recharge periods. To evaluate the capabilities of this proposal, this paper focuses on a backward calculation analysis of a single actuator operating with multiple pump/motors connected to each chamber. A series of hydraulic machines with fixed displacement and identical sizes are connected to the actuator chambers through on/off directional valves. The system controls the flow by using the required pumps and selecting their optimal speeds to minimize energy consumption or maximize energy recovery. The results show how the number of pumps affects the system’s performance and provide insights regarding the selection of operating machines according to the actuator speed and force.
Control of Hydraulic Injection Moulding Machine With Electro-Hydraulic Variable-Speed Drive
Authors: Hertz Rasmus A. , Therkelsen Ole , Kristiansen Søren , Christensen Jesper K. , Hansson Frederik A. , Schmidt Lasse
Published: November 2023

In this work an industrial hydraulic injection moulding machine, is retrofitted with a electro-hydraulic variable-speed drive. The focus is placed on the injection cylinder, where the design of the hydraulic system is realized with standard components. The design is based on two permanent magnet synchronous motors connected to two fixed displacement pumps, allowing the control of the injection cylinder without the need for valves in the flow path, removing the dynamic influence of a valve and reducing throttle losses. The controller structure is designed from a model-based approach, where the electric motors and associated drives are operated in speed control modes. A sum and load pressure decoupling control structure is proposed, enabling the use of SISO control design for the pressure level and the load pressure separately. For the latter, a cascaded hydraulic drive controller structure is proposed, where the inner loop consists of a pressure controller, and the second and third loop consists of a velocity and position controller respectively. A method to smoothly switch from velocity to pressure control is furthermore proposed. Experimental results comparing injection cycles of an industrial injection moulding machine and the retrofitted injection drive and proposed control are presented.
Slipper Wear in Variable Operating Conditions
Authors: Merkel Philip Amos , Duensing Yannick , Schmitz Katharina
Published: November 2023

Electro-hydrostatic actuators (EHA) offer highperformance hydraulic control while featuring a range of advantages compared to classic valve-controlled actuation. They are highly efficient, modular, power-by-wire actuators thus enabling the design of efficient hydroelectric drives urgently needed for the electrification of hydraulic machinery. EHAs are therefore steadily replacing valve-controlled actuators in many applications. However, in some cases, the robustness of the existing EHA systems has proven to be insufficient for their respective applications. Especially pumps are known to limit the service life of EHAs. [1]

A very commonly used pump type here is the axial piston pump. The robustness of its hydrostatically partially balanced contacts has proven to be particularly challenging under the variable load conditions typically arising in EHA applications. [1], [12], [13]

This contribution aims at the description of the relevant wear effects on the slipper-swashplate contact under variable load conditions as well as the impact of the wear on the load-carrying capabilities of the slipper contact. For this, occurring wear is experimentally identified on component-level tests. A simulative elastohydrodynamic lubrication study of the slipper-swashplate contact allows the identification of the wear progress as well as a study of the influence of existing wear profiles on the slipper behavior.
Bandwidth Expansion and Resonance Suppression for High-Frequency Electro-Hydraulic Acceleration Control System by Three-Variable Control Method With Dynamic Pressure Feedback
Authors: Luo Guifu , Yang Tingming , Mu Ziyang , Zou Jun , Zhou Hua , Yang Huayong
Published: November 2023

Due to the characteristics of high-power density, the high-frequency electro-hydraulic acceleration control system (HFEHACS) has been an important component of vibration simulation equipment such as load simulators, and fatigue testing machines. However, the performance of the HFEHACS is strongly restricted by the inherent low bandwidth and low damping ratio of the electro-hydraulic subsystem. In general, these two shortcomings must be traded off to achieve the desired compromise performance. To expand the bandwidth and increase the damping ratio of the electro-hydraulic subsystem simultaneously, an improved control method that combines the three-variable control (TVC) method with dynamic pressure feedback was proposed in this work. First, the dynamic model of the high-frequency electro-hydraulic subsystem with an elastic base considered was established, and the influence of the elastic base on the HFEHACS was analyzed by simulation. Second, the basic TVC was designed to expand the bandwidth and suppress the resonance of the electro-hydraulic subsystem previously, after that, the dynamic pressure was estimated and added into the control method for increasing the damping ratio of the system and further suppressing the resonance of the system. Third, simulations and experiments were conducted to verify the effectiveness of the improved control method. Simulation results showed that the resonance of the HFEHACS caused by both the electro-hydraulic system and the elastic base could be suppressed well by the improved TVC. Experiments results showed that the bandwidth of the electro-hydraulic subsystem with the proportional controller could be expend to about 190Hz, and the bandwidth of the system with the traditional TVC method could be expanded to nearly 250Hz with relatively apparent resonance, while the bandwidth of the system with the proposed method was expanded to 250Hz with smaller resonance. Thus, the effectiveness of the proposed method in expanding the system bandwidth and reducing the system resonance simultaneously was demonstrated.
Flow Ripple Minimization in a Triplex Pump Through the Implementation of Various Linkage Mechanisms
Authors: Herrera-Perez Martin S. , Morse Kristen , Nahin Md Minal , Van de Ven James D.
Published: November 2023

A significant amount of research has been conducted to reduce the outlet flow ripple in pumps. The approach usually focuses on techniques to improve valve timing, but few attempts have been made to achieve this improvement from the piston trajectory itself. This paper investigates how the flow ripple in a triplex pump is influenced by the implementation of different linkage mechanisms that allow direct tuning of the piston trajectory. The model of a baseline pump with a displacement of 10 cc/rev and operating pressures that range from 5 to 50 MPa is built to account for the kinematics and pressure dynamics of three linkage configurations: (1) inline crank-slider, (2) offset crank-slider, (3) Watt-II crank-slider. The kinematics of the linkage configurations (2) and (3) are optimized to minimize output flow ripple. Flow ripple reductions of 10% and 25% are found for the offset crank-slider and Watt-II crank-slider respectively, compared with the inline crank-slider. Tradeoffs between kinematic and dynamic flow ripple are observed as the pump model is evaluated at various operating pressures. An optimum Watt-II linkage mechanism with a kinematic and dynamic flow ripple of 10.6% at 5 MPa is found and described in this paper along with its performance across a wide range of operating pressures.
Modelling of the Entire Aircraft Fuel System Through Simulink for Accurate Performance Evaluation
Authors: Sciatti Francesco , Tamburrano Paolo , Distaso Elia , Amirante Riccardo
Published: November 2023

As the primary fluid system in aircraft, the fuel system plays a vital role in storing, controlling, and continuously providing a clean flow of fuel to the engine throughout all flight phases. Considering that any fuel system malfunctions can lead to decreased engine performance and increased fuel consumption, it is crucial for the system to function efficiently to ensure aircraft safety and reliability. In gas turbine engines that utilize kerosene-based fuels, such as jet fuels, the fuel system comprises several components, including fuel tanks, fuel lines, centrifugal boost pumps, filters, main fuel pumps, fuel metering units (FMUs), and fuel injector nozzles. The FMU is of utmost importance since it regulates the fuel flow rate delivered to the combustion chamber and controls the angle position of the inlet guide vanes (IGVs). In light of the current dearth of comprehensive simulation models of aircraft fuel systems in the scientific literature, the goal of this paper is to create a highly accurate numerical code that reflects the entire fuel system of a gas turbine engine for aircraft. To ensure the accuracy of the proposed model, well established and referenced equations are used. Firstly, a layout for the fuel system is introduced, followed by an assessment of the computational model created using the software Simulink. Afterwards, the simulation results obtained via closed-loop control are presented and discussed.
Human-in-the-Loop Motion Control of a Two-DOF Hydraulic Backhoe Powered by the Hybrid Hydraulic Electric Architecture (HHEA)
Authors: Chatterjee Arpan , Li Perry Y.
Published: November 2023

The Hybrid Hydraulic-Electric Architecture (HHEA) combines the respective power density and control advantages of hydraulic and electric actuation to save energy for off-road vehicles. It uses a set of selectable common pressure rails to transmit the majority of power and electric actuation to modulate that power. As it is critical that off-road vehicles can perform tasks dexterously and exactly as commanded by the operator, the switchings between discrete pressure rails pose a potential challenge for smooth and precise motion. A control strategy consisting of a backstepping nominal control and least norm transition control has previously been developed to address this issue. It has been tested on 1 degree of freedom (DOF) testbeds where known trajectories were able to be tracked precisely. This paper presents the implementation of the HHEA motion control strategy on a 2-DOF backhoe operated by a human operator via a 2-DOF joystick. Unlike previous studies, the duty cycle is unknown beforehand and the decision to change pressure rails is taken in real-time. The efficacy of the motion control strategy has been validated experimentally. Several strategies to improve the user interface: control in workspace coordinates, pressure feedback, and velocity field-based task specification, have also been implemented and demonstrated to make operating the multiple DOF, HHEA actuated machine more intuitive to novice operators.
A Digital Hydraulic Full-Bridge Oscillation Transformer
Authors: Johansen Per , Hansen Anders Hedegaard
Published: November 2023

As emission standards around the world grow more stringent, construction equipment manufacturers are looking towards electrification. A variety of electrified machines are being brought to market, dramatically reducing emissions of carbon dioxide, nitrogen oxide and acoustic noise. However, electrification comes with challenges as the machine’s ability to perform a full day’s work on a single charge is imperative. OEMs must balance battery cost with the power and range requirements of the machine without creating price-prohibitive products. Adding extra battery power to enable longer runtime adds expense, and therefore in the pursuit to balance extended runtime, without excessive battery costs, the inefficiency of hydraulics is the prime target. In this paper we present a novel linear transformer based on the digital displacement technology. The transformer differs from other linear topologies in that the piston is free-floating and the chambers are operated similar to digital displacement unit chambers, where switching losses are minimized with timely operation of the low- and high-pressure manifold valves in relation to the compression and decompression of the displacement chamber. While exhibiting the disadvantage of a single piston machine in terms of vibrations, the mechanical construction of the transformer is simple compared to rotational piston-type displacement units, however the simplicity comes with the cost of complicated control. The research target is to develop a small, efficient, high-frequency transformer, which can replace the inefficient control valves in common-pressure-rail systems. A prototype designed for operation of the boom in an electrified wheel loader is presented.