High Performance Operation Research Articles

High-Performance Shear Mode Ultrasonic Transducer Operating at Ultrahigh Temperature Fabricated with Bi12SiO20 Piezoelectric Crystal.

Shear mode ultrasonic waves are in high demand for structural health monitoring (SHM) applications owing to their nondispersive characteristics, singular mode, and minimal energy loss, especially in harsh environments. However, the generation and detection of a pure shear wave using conventional piezoelectric materials present substantial challenges because of their complex piezoelectric response, involving multiple modes. Herein, we introduce a high-quality piezoelectric crystal Bi12SiO20 (BSO), exhibiting a robust piezoelectric response (d14 = 45.1 pC/N) and a pure vibration mode. Thereafter, we developed a BSO-based shear mode ultrasonic transducer and conducted finite element simulations and experiments. Results indicated that the proposed transducer excels in exciting and receiving pure shear waves with a high signal-to-noise ratio across a wide operating frequency range. Remarkably, the proposed transducer demonstrates efficacy ranging from 25 to 800 °C, which exhibits an exceptionally high operating temperature. These excellent attributes, coupled with cost-effectiveness, render this crystal highly promising for practical SHM applications.

UV/Ozone-Induced Interface Engineering for High-Performance Horizontal Organic Light-Emitting Transistors Operating at Low Voltage.

Multifunctional organic light-emitting transistors (OLETs), which combine electric-switching and light-producing capabilities into a single device, are attracting increasing interest as promising candidates for new-generation display technology. Despite advancements in the design of organic luminescent materials and the optimization of device geometry configurations, maintaining operating voltage low while enhancing optical performances remains a key challenge in horizontally structured OLETs. Here, a simple and effective interfacial engineering strategy is employed to improve the optical properties of horizontal OLETs operating at low voltage, by introducing ultraviolet ozone (UVO)-induced surface modification on high-k dielectrics. It takes the role to not only control the surface activation states of dielectric layers but also optimize the growth dynamics behavior of channel film benefitting from the strong interfacial interaction between chemically modified dielectric surface and channel seed molecules. The optimized horizontal-channel OLET exhibits a significantly high brightness of 9,484 cdm- 2, more than 25 times greater than that of untreated OLETs (347 cdm- 2), along with a peak EQE of 9.64%, a low operating voltage of 15 V, and good dynamic gate stress stability, outperforming other reported horizontal-channel high-performance OLETs. This work demonstrates that dielectric/semiconductor interface engineering is essential for high-performance transistor-based optoelectronic devices including horizontal OLETs.

Investigation of the Effects of Design Parameters on Tooth Profile Formation and Operating Performance in Cycloidal Reducers

Cycloidal reducers have a unique and complex tooth profile design compared to conventional gear systems. Unlike standardized gear profiles, cycloidal reducers provide significant flexibility in design parameters such as module, profile modification coefficient, and eccentricity. However, these parameters interact in a complex manner, affecting both tooth profile formation and the overall performance of the reducer. Inaccuracies in selecting parameters may lead to problems such as excessive contact stress, gear deformation or reduced load transfer efficiency. This study aims to investigate the effects of design parameters on the formation of cycloidal tooth profiles and the operating performance of reducers. By analyzing the relationships and interactions between these parameters, the research provides a deeper understanding that will improve design processes, enhance performance, and contribute to future standardization efforts. As a result, this study aims to contribute to the development of cycloidal reducers that are structurally robust, efficient and suitable for high-performance operation.

Improving the reliability of power drives for marine and crane equipment by schematic layout methods

This article is devoted to the problem of increasing the reliability of special power drives designed exclusively on the basis of cylindrical gear ordinary and singlerow planetary mechanisms that allow you to create multifunctional, hightech products endowed with equalizing properties that eliminate overestimation of the mass of nodes and the associated mass of metal structures, provide the product with high technical, economic and operational performance. Complex composite gears with a differential are considered, in which all links are movable, which allows it to work with various functions of branching power flows: distribute movement to several consumers; summarize several independent movements requiring rotation of their input links in one or different directions; create systems with superimposed adjusting motion and systems with stepless regulation, as well as solve other tasks. The main attention is paid to torque distributors, which, with one leading link, have several driven links. Distributors with two slave links are most often used in marine and crane equipment. The development of the theory of transmission of such devices has its own characteristics and is impossible without taking into account their energy kinematic state. The properties of the differential mechanism are formulated and analytical dependencies are built on their basis, with the help of which it is possible to create a distributor with specified kinematic, power, and energy parameters, taking into account the schematic layout requirements. To increase the reliability of distributors with a high value of the total gear ratio, solutions have been developed that simplify the design of the power drive; for structures providing a given misaligned arrangement of the drive shafts, solutions have been proposed that exclude the presence of open gears. All this taken together will contribute to the development of scientific approaches to the design and design of modern models of power drives.

Effect of Spindle Deviation on the Performance of Adjustable Ejectors

Due to the change of working load caused by peak shaving and frequency modulation in power plants, the traditional fixed ejector cannot meet the requirements of high-performance operation under variable load conditions. However, the adjustable ejector with spindle has problems such as the length of the spindle is too long, and the anti-vibration measures are not in place. The spindle vibrates and deflects during the operation of the ejector. In this research, the influence of the structure deviation of the spindle on the ejector performance is evaluated by numerical simulation. The results show that the spindle of the adjustable ejector can obtain the maximum secondary fluid mass flow by controlling the primary fluid. Under different operating conditions, the entrainment ratio of the adjustable ejector is improved by 114.7% compared with that of the fixed ejector. The structural deviation will reduce the entrainment ratio and anti-back pressure capability, and the ejector will change from the critical mode to the sub-critical mode. The deviation between the spindle and the primary nozzle will change the flow field inside the primary nozzle, thus affecting the primary fluid ejection direction and the entrainment ratio.

Enabling Low Iridium Loadings and Reduced Catalyst Material Cost for PEM Water Electrolyzers Via Composite Anode Design with Conductive Additive

The production of inexpensive, clean hydrogen will be vital for supporting wide decarbonization efforts across the sectors of industrial chemicals, transportation, and the electric grid. Proton exchange membrane water electrolysis (PEMWE) has great potential as a low-temperature, high current density option for low-carbon hydrogen production; however, at present one of its most significant barriers to widespread commercial adoption is the high cost associated with the iridium (Ir) anode catalyst1.Unfortunately, many problems arise when lower Ir loadings are attempted. When considering catalyst layers (CLs) comprised only of IrO2, decreasing Ir loadings directly correlates to diminished mechanical robustness and electrode thickness. In this case, low Ir loading anodes can suffer large performance limitations caused by reduced in-plane electrical conductivity and poor interfacial contact with the porous transport layer (PTL), both of which are known to be crucial for good electrolyzer performance2,3. Some success in reaching sufficient activity with lower loadings has been achieved by synthesizing IrO2 particles on a supporting material4, but these anodes are often limited by high insulating characteristics of viable supports as well as additional chemical processing steps. Towards this end, the next decade’s targets for low Ir loadings and high Ir-specific performance urgently necessitate new designs and methods for fabrication of the PEMWE anode.Herein, we present the successful implementation of a composite anode structure using a conductive additive to enable low Ir loadings for PEMWE while maintaining robust, high-performance operation. As an initial demonstration, we simply use platinum (Pt) black as the conductive additive given its high known electrical conductivity, acid-stability, and a price that is current one-fifth that of Ir5. Results are compared across various loadings of pure-IrO2 anodes, a composite anode with Pt black, and a pure-Pt-black anode. We show physical characterization results from SEM images and four-point probe measurements for sheet resistance, finding that the addition of Pt black reduced electrode sheet resistance by four orders of magnitude. We also present electrochemical characterization results, which revealed that when compared to a high Ir loading anode, the composite anode facilitated a 95% reduction in Ir loading and 80% cost reduction of the anode catalyst materials while maintaining equal current density performance @Ecell = 1.8 V. With this method, we show promising results towards lowering Ir loadings and material costs, addressing a major barrier to the widespread adoption of PEMWE for clean hydrogen production.References K. Ayers, Curr Opin Chem Eng, 33, 100719 (2021).Z. Taie et al., ACS Appl Mater Interfaces, 12, 52701–52712 (2020).E. Leonard et al., Sustain Energy Fuels, 4 (2020).L. Moriau, M. Smiljanić, A. Lončar, and N. Hodnik, ChemCatChem, 14 (2022).“PGM Management,” Johnson Matthey, https://matthey.com/products-and-markets/pgms-and-circularity/pgm-management (accessed 2024-02-15).

Advanced Eutectogel Electrolyte for High-Performance and Wide-Temperature Flexible Zinc-Air Batteries.

Despite ongoing challenges, achieving further breakthroughs in the development of gel polymer electrolytes with a wide temperature range, excellent liquid retention capability and enhanced anode compatibility in flexible zinc-air batteries (FZABs) remains a significant objective. This study presents a significant advancement in the development of choline chloride/ethylene glycol-polyvinyl alcohol (ChCl/EG-PVA) eutectogel electrolyte, tailored for high-performance operation across a wide temperature range. Systematic in-situ and ex-situ characterizations and theoretical simulations confirm the formation of robust hydrogen bonding and denser polymer cross-linked networks within the prepared eutectogel, leading to enhanced liquid retention ability (93.7 % after 96 h exposure to air) and ion transport capacity (ionic conductivity of 171.3 mS cm-1). Additionally, the zincophilicity nature of the choline cation in eutectogel effectively suppresses dendrites growth. The assembled FZAB utilizing this eutectogel electrolyte achieves a peak power density of 109.3 mW cm-2 and a cycle life of 90 h. Notably, the power density of FZAB is maintained as high as 38.2 mW cm-2 at -40 °C and 63.2 mW cm-2 at 50 °C, demonstrating its prominent suitability for applications in extreme temperature conditions. The design of eutectogel provides a novel way to achieve the high-performance FZAB.

Thermodynamic analysis and performance optimization on an ultra‐low‐temperature cascade refrigeration system using refrigerants R290 and R170

AbstractTo meet the strict requirement on whole chain of vaccine production, storage, transportation, and distribution, most researches have been done on cascade refrigeration systems to achieve high operation performance, while a research gap on the performance exploration of eco‐friendly refrigeration systems still exists. In this paper, a comprehensive thermodynamic model was established to analyze the operation performance of a pre‐cooled cascade refrigeration system with eco‐friendly refrigerants propane (R290) and ethane (R170). Based on the present thermodynamic model, the performance optimization on the R290‐R170 cascade refrigerator was made with considerations of degree of subcooling, degree of superheat, evaporation temperature, condensation temperature, cascade condensation temperature, and cascade temperature difference. Variations of the coefficient of performance, exergy destruction, and total exergy efficiency of the refrigeration cycle were analyzed. Two mathematical correlations yielding the optimal cascade condensation temperature and maximized coefficient of performance were developed by multilinear regression analysis. When the evaporation temperature is − 60°C, the maximized coefficient of performance and total exergy efficiency are 1.276 and 49.51%. This paper demonstrates the potential for improving the R290‐R170 cascade refrigeration system and furnishes the basis for further exploration on ultra‐low‐temperature refrigerators.

Research on online optimization scheme and deployment of PMSM control parameters based on honey badger algorithm

Permanent magnet synchronous motor (PMSM) drive systems are receiving increasing attention due to their superior control quality and efficiency. Optimizing the control parameters are key to achieve the high-performance operation of PMSMs. Although heuristic algorithms demonstrate excellent optimization outcomes in simulations, there are still challenges in deploying optimization schemes in practical drives. In this study, a real-time online deployable control parameter optimization scheme is proposed. The optimization effect is evaluated through the system step response performance, and a framework for deploying optimization algorithms within the driver is developed. A fault suppression mechanism is also designed to mitigate overshoot and vibration issues caused by suboptimal solutions. The proposed scheme is validated on a rapid prototyping control platform. Experimental results confirm that the scheme exhibits good optimization performances across various operating conditions. The honey badger algorithm employed in this paper shows faster convergence and more stable optimization effects than other optimization algorithms. The optimization effect is improved by 2.2% and its performance in terms of consistency across multiple optimization results has increased by 40%.

Enhancing high-order harmonic mode-locking in Er/Yb-Doped fiber lasers with sub-MHz fundamental frequency via optoacoustic resonance

We present an experimental study of a long Er/Yb-doped fiber ring laser with a low fundamental frequency of 0.678 MHz. By solely adjusting the quarter-wave plate in the polarization controller, we uncovered a series of reproducible laser generation regimes. Among these, multiple soliton bunches were harmonically mode-locked to low-order cavity harmonics (from the 3rd to the 8th). Notably, we also identified a regime featuring a stable soliton train harmonically mode-locked to the 472nd cavity harmonic at 320 MHz. This regime demonstrated exceptional harmonic mode-locking stability, with a supermode suppression level of 49 dB corresponding to the timing jitter on the order of a few picoseconds. We attribute this remarkable stability to an exact optoacoustic resonance between the laser repetition rate and the fiber eigen acoustic mode frequencies, specifically identified as R06 and TR2,15. These findings represent a significant advancement in high-performance fiber laser operation, particularly in enhancing the stability of lasers with sub-MHz fundamental frequencies capable to generate regular pulses with much higher repetition rates.

An estimation method for vision-based autonomous landing system for fixed wing aircraft

In this paper, we propose a vision-based estimation method for autonomous landing of fixed-wing aircraft for Advanced Air Mobility. The concept of autonomous flight with minimal human intervention has gained significant interest with a particular focus on autonomous landing. The goal is to overcome the limitations of existing instrument landing systems and reduce reliance on GNSS during aircraft landing. The proposed system leverages the following techniques for high-performance and real-time operations in various real-world environments and during all stages of landing. A deep learning segmentation model was directly learned, created, and used for robust runway recognition performance against environmental changes around the runway. Algorithms were designed to adapt to different flight stages considering the varying information offered by image data when the aircraft is in mid-air and on the ground. The relative lateral position from the aircraft to the runway was estimated using bird’s-eye-view conversion and inverse projection techniques instead of conventional perspective-n-point methods for reducing the recognition error occurring from the conversion between 2D image and 3D world. Finally, the mixed-precision technique was used for the segmentation model to improve inference speed and ensure real-time operation in real-world deployment. Estimation stability and reliability were improved by using a Kalman Filter to cope with sensor uncertainties caused by the real-world flight environment. Consequently, we show that the average error in the lateral position estimation by the proposed method is comparable to the accuracy of a single GNSS and demonstrate successful autonomous landing of our test aircraft with a set of flight tests.

Elucidating the Performance Limitations of a 25 cm2 Pure‐Water‐Fed Non‐Precious Metal Anion Exchange Membrane Electrolyzer Cell

AbstractAnion exchange membrane (AEM) water electrolysis has emerged as a promising technology for producing hydrogen in a carbon‐neutral economy. To advance its industrial application, performance evaluations of non‐precious metal AEM electrolyzers with electrode areas of 25 cm2 were conducted. The focus was on pure water operation, achieving a current density of 0.26 A cm−2 at a voltage of 2.2 V. To gain a better understanding, the AEM electrolyzer was also operated in aqueous KOH, yielding 1.2 A cm−2 at 2.2 V. By adding a liquid electrolyte and by varying cell components, causes of the occurring performance limitations and ways to improve the AEM electrolyzer were identified. Electrochemical impedance analysis showed that the activation loss at the anode due to sluggish OER kinetics was the limiting factor at low current densities. At higher current densities, which is the operating range of interest for industrial application, the ohmic resistance from the membrane was the dominant factor limiting high performance in pure water operation.

Toroidal distribution of heat load on castellated plasma facing components for lower divertor target in EAST

In tokamak devices, the performance of plasma facing components (PFCs) under high heat loads is a key challenge for achieving long-pulse and high-performance plasma operations. The lower divertor of EAST adopts an ITER-like cassette modules (CMs) structure. However, regular distribution of damage along the toroidal direction have been observed on the divertor target plates, which not only affects the lifespan of PFCs but also limits the long-pulse and high-performance plasma operations. Therefore, investigating the toroidal distribution of the heat load on the divertor target in EAST is crucial for understanding the mechanism of damage on the target plate surface. The toroidal characteristics of heat loads on CMs of the lower divertor in EAST was analyzed using a three-dimensional magnetic field line tracing program (PFCFlux). For the inner vertical target (IVT) and outer vertical target (OVT) within a single CM, the heat load varies monotonically along the toroidal direction. In contrast, the heat load distribution on the outer horizontal target (OHT) is uniform, except at the chamfers, which is directly correlated with the target’s geometric structure and the magnetic field configuration. The surface heat load distribution exhibits toroidal non-uniformity, with the heat deposition pattern being generally consistent and displaying periodic variations. The toroidally uneven heat load distribution is attributed to the change in the magnetic field’s tilt angle. Additionally, the peak heat load is observed at the chamfer positions between cassettes, and an analysis is conducted on the relationship between peak heat load and the size of the chamfer. Smaller tilt angles result in lower surface heat load. Furthermore, a comparative analysis of peak heat loads at the chamfer under different plasma current conditions reveals that higher plasma currents generally result in increased peak heat loads. This investigation into the toroidal heat load distribution on the divertor surface contributes to understanding of the damage mechanism of W PFC as the target plate and provides valuable data for divertor design of future fusion devices.

Amplitude and time response characterization of avalanche signals in InGaAs single-photon avalanche diode

Photon and dark avalanche signals of InGaAs single-photon avalanche diodes (SPAD) are detected and counted indiscriminately, while their specific characteristics are not well understood, which hinders further performance optimization of InGaAs SPAD. Here, we investigate back-incidence InGaAs SPAD operating at room temperature by designing a dual-threshold discriminator and tuning the threshold voltage. The photon count rate and dark count rates (DCR) exhibit different abrupt-voltage variations with the threshold voltage, and the amplitude distribution of dark avalanche signals is more concentrated and slightly larger than that of photon avalanche signals. The smaller photon avalanche signals have a faster time response. It can be inferred that the above characteristics are related to the photon absorption position and carrier transport, depending on physical structure and operating mode, and dark counts are mainly caused by holes drifting from N-type material. We use a dual-threshold discriminator to reduce the time jitter and DCR caused by thermally excited carriers. The experimental results are in good agreement with theoretical analysis, indicating that the insertion of an i-InP layer or the use of a front-incidence technique can further optimize the overall performance and enable InGaAs SPAD with high performance operation at room temperature.

Smart material selection strategies for sustainable and cost-effective high-performance concrete production using deep learning

The creation of high-performing concrete (HPC) is greatly influenced by the selection of materials, with cost and sustainability factors playing a bigger part in contemporary building techniques. To overcome these limitations, we developed a Multi-Objective Ant Colony Adaptive Dense Convolutional Neural Network (MOAC-ADenseNet) with 5-K-Fold cross validation, a dependable and precise forecasting model for the cost-effective selection of HPC material. First, we collect a concrete material dataset for evaluating the suggested method. MOAC-ADenseNet utilized Dense convolutional neural networks and ant colony optimization for complex material data analysis, which makes it easier to choose expensive and sustainable materials for high-performance concrete manufacturing operations. The experimental findings of the suggested approach are evaluated for the relative measure such as Pearson's Linear Correlation Coefficient (R) is 0.93, the Root Mean Square Error (RMSE) is 91.38, Mean Absolute Error (MAE) of 58.15, and Mean Absolute Percentage Error (MAPE) is 8.79. The outcomes demonstrated that the material cost of HPC was correctly predicted by the MOAC-ADenseNet. The actual measured value and the MOAC-ADenseNet model predictions, following 5-K-fold cross-validation and input feature improvement, shows its effectiveness. A The MOAC-ADenseNet approach provides feasible method for enhancing material selection in HPC manufacturing accomplishing sustainability and cost-effectiveness goals.

Enabling Low Iridium Loadings and Reduced Catalyst Material Cost for PEM Water Electrolyzers Via Composite Anode Design with Conductive Additive

Herein, we present the successful implementation of a composite anode using a conductive additive to enable low iridium (Ir) loadings for PEMWE while maintaining high-performance operation. We use platinum (Pt) black as the conductive additive given its high electrical conductivity, high stability, and a price currently one-fifth that of Ir. Using a high loading of Pt black conductive additive allowed for retained electrode thickness, good dispersion of Ir particles, and drastically decreased sheet resistance at low Ir loadings of 0.10 mgIr cm-2. Compared to a standard Ir oxide anode with high, commercially relevant Ir loading, a composite anode with a low loading of 0.10 mgIr cm-2 achieved an equal current density performance at 1.8 V, translating to a 95% reduction in loading and 80% cost reduction of the anode catalyst materials.

Benign Saturation of Ideal Ballooning Instability in a High-Performance Stellarator.

To examine the robustness of the designed 5% β limit for high-performance operation in the W7-X stellarator, we undertake nonlinear magnetohydrodynamic (MHD) simulations of pressure-driven instabilities using the m3d-c1 code. Consistent with linear analyses, ideal ballooning instabilities occur as β exceeds 5% in the standard configuration. Nonetheless, the modes saturate nonlinearly at relatively low levels without triggering large-scale crashes, even though confinement degradation worsens as β increases. In contrast, in an alternative configuration with nearly zero magnetic shear, ideal interchange modes induce a pressure crash at β=1%. These results suggest that the standard W7-X configuration might have a soft β limit that is fairly immune to major MHD events, which enhances the appeal of the stellarator approach to steady-state fusion reactors.

Enabling Low Iridium Loadings and Reduced Catalyst Material Cost for PEM Water Electrolyzers Via Composite Anode Design with Conductive Additive

Herein, we present the successful implementation of a composite anode using a conductive additive to enable low iridium (Ir) loadings for PEMWE while maintaining high-performance operation. We use platinum (Pt) black as the conductive additive given its high electrical conductivity, high stability, and a price currently one-fifth that of Ir. Using a high loading of Pt black conductive additive allowed for retained electrode thickness, good dispersion of Ir particles, and drastically decreased sheet resistance at low Ir loadings of 0.10 mgIr cm-2. Compared to a standard Ir oxide anode with high, commercially relevant Ir loading, a composite anode with a low loading of 0.10 mgIr cm-2 achieved an equal current density performance at 1.8 V, translating to a 95% reduction in loading and 80% cost reduction of the anode catalyst materials.

Nonlinear flow modeling of electro hydrostatic pump unit based on Gauss Newton iterative method for high performance control

For the electric hydrostatic pump unit (EPU), which is a crucial component in the electro hydraulic servo pump control system (EHSPCS), nonlinear flow modelling is a key challenge to achieve high performance operation, especially in position control. For the nonlinear flow of EPUs, simple linearization combined with compensation has become a popular control method recently. However, the control performance is constrained by the reliance on deviation correction. This paper proposes utilizing the Gauss Newton iterative method to investigate the nonlinear flow modeling in the EPU, aiming to obtain the mapping relationship between the load flow and operating parameters in the EPU, thereby directly improving the control performance. A nonlinear flow model is built by utilizing the Gauss Newton iterative method based on test data obtained from various operating conditions, and the mapping relationship is presented accordingly. Experimental studies show that compared to well-established methods, this model exhibits high accuracy and practicality in improving the control performance, particularly in position control of the EPU.

Composite Anode for PEM Water Electrolyzers: Lowering Iridium Loadings and Reducing Material Costs with a Conductive Additive.

To enable the greater installed capacity of proton exchange membrane water electrolysis (PEMWE) for clean hydrogen production, associated costs must be lowered while achieving high current density performance and durability. Scarce and expensive iridium (Ir) required for the oxygen evolution reaction (OER) is a large contributor to the overall cost, yet high loadings of Ir (1-2 mgIr cm-2) are currently needed in commercial systems to maintain sufficient activity, conductivity, and durability. To meet the aggressive targets for low Ir loadings, we introduce a composite anode approach using a conductive additive that is less expensive than Ir to facilitate robust, high-performance operation with low Ir loading by retaining electrode thickness and in-plane electrical conductivity. In this demonstration, we use platinum (Pt) black as the conductive additive given its high electrical conductivity, acid stability, and current price one-fifth that of Ir. Using a high-activity commercial Ir oxide (IrO x ) catalyst, we present a 95% Ir loading reduction and 80% cost reduction of the anode catalyst materials while maintaining equal current density performance at a cell voltage of 1.8 V. Furthermore, we show enhanced stability of a composite anode compared to an IrO x anode with loadings of 0.10 mgIr cm-2 via accelerated stress test (AST) and postmortem imaging. With this approach, we show promising results toward lowering Ir loadings and material costs, addressing a significant barrier to the widespread adoption of PEMWE for clean hydrogen production.