High Speed Research Articles

Amp-Holo-Net enables speckle-free and high-quality coaxial amplitude-only holographic display

At present, amplitude-only holograms (AOH) are widely applied because of the high response speed and small pitch of amplitude spatial light modulators. However, AOHs are generally generated by traditional diffraction theories, and there are no effective deep learning algorithms to generate high-quality coaxial AOHs, which makes it difficult to achieve speckle-free, high-quality holographic displays using amplitude spatial light modulators. Thereby, we propose two cascaded deep neural networks, embedding physical models of the coaxial AOH to generate speckle-free and high-quality coaxial AOHs within an acceptable time, named Amp-Holo-Net, which is the first work that introduces deep learning to generate coaxial AOHs. We demonstrate the superiority of the proposed method through simulation, achieving an 81% reduction in speckle contrast of two-dimensional (2D) monochrome reconstruction and a 60% improvement in peak signal-to-noise ratio of 2D color reconstruction compared with point source method, and optical experiments are conducted to verify the validity of the proposed method. We believe our method fills the blank of AOH algorithms and paves the way for holographic displays based on amplitude spatial light modulators.

Ocean current turbine power take-off design using fluid dynamics and towing tank experiments

This study investigates the performance and power generation capabilities of a small-scale hydrokinetic turbine by comparing numerical simulations with experimental measurements. The key difference between the two models comes from the initial numerical analysis which focused only on the permanent magnet DC motor (PMDC) motor’s parameters and did not account for the gear-head reduction that leads to discrepancies in current and torque predictions, especially at lower input voltages. In practice, friction losses within the gear-head increased the required current and torque, highlighting inefficiencies in the motor gear-head system. A modified experimental setup incorporated a magnetic coupling to address leakage issues and enhance system reliability. While the magnetic coupling resulted in a slight reduction in speed, current, and torque, it improved the overall integrity of the system which is essential for marine applications. The comparison between experimental results and Blade Element Momentum (BEM) simulations showed good agreement at lower speeds, but the simulations under-predicted power at higher speeds, likely due to the model’s limitations in capturing complex hydrodynamic phenomena. This shows the need for comprehensive analysis, integrating both numerical and experimental approaches to optimize turbine performance. Future research will focus on refining experimental methodologies and further improving turbine design and efficiency for hydrokinetic energy systems.

Feasibility of Using Inertial Measurement Units (IMUs) to Augment Cadaveric Temporal Training

ObjectiveInsertional speed of cochlear implant electrode arrays (EA) during surgery is correlated with force. Low insertional speed, and therefore force, may allow for preservation of intracochlear structures leading to improved outcomes. Given the importance of low insertional speeds, we investigate the feasibility of using inertial sensors for kinematic analysis during EA insertion to augment otolaryngology‐head and neck surgery training.MethodsPracticing otolaryngology surgeons were recruited and inertial measurement units (IMU; Metamotions+, MBIENTLAB Inc, San Jose, CA) consisting of accelerometers were used to measure hand speed during EA (Cochlear™Nucleus®CI522 cochlear implant with Slim Straight electrode, Cochlear Limited, Sydney, Australia) insertion into a cadaveric cochlea. A mixed regression model was utilized to determine differences in speed across trials within a surgeon.ResultsA total of nine trials were performed by three surgeons. The highest mean ± SD speed obtained was 8.4 ± 1.7 mm/s, and the highest speed was 22.5 mm/s. Mean speed was not significantly different across trials within surgeons (p > 0.05).DiscussionIMUs are relatively inexpensive and relatively easy to use sensors that provide information on variables that may be of interest for otolaryngology resident training. The use of IMUs as part of advanced temporal training for cochlear electrode insertion can provide insight into hand speed, thereby allowing residents to train with specific regard to this variable. Future randomized‐controlled trials can be carried out to determine whether IMUs are conducive to lower insertional speeds.Level of EvidenceNA Laryngoscope, 2024

Picosecond Operation of Optoelectronic Hybrid Phase Change Memory Based on Si‐Doped Sb Films

AbstractPhase‐change random access memory is anticipated to break the bottleneck of the “storage wall” due to its advantages in simultaneous data storage and in‐memory computing. However, operation speed constrains its application scenarios. Antimony (Sb) thin film has ultrafast phase change speeds, low power consumption, and a straightforward chemical composition. In this study, silicon (Si) doping is employed to enhance the stability of pure Sb while achieving both ultrafast operational speeds and superior thermal stability concurrently. By utilizing optoelectronic hybrid phase change memory, the SET and RESET operation speeds can reach as fast as 26 and 13 ps, respectively, when using Si‐doped Sb films. The absence of the Si─Sb bond results in simple cubic nuclei within the amorphous film, which is posited as the structural basis for the high operational speed. These novel insights into ultrafast speed and phase mechanisms are poised to have valuable evidence for future high‐speed memory designs.

Thermal-Gas-Elastic Coupling Modeling and Performance Analysis of Foil Cylindrical gas Film Seal Considering Speed Slip, Temperature Jump and Shaft Misalignment

Abstract The Compliant foil cylindrical gas film seal is an advanced sealing technology designed for high-speed and high-temperature conditions in a jet engine. Its design involves using a compliant foil to create a cylindrical sealing surface, achieving adaptive sealing in environments with high pressure differences and rotational speeds. For high-speed and high-temperature operation, a speed slip flow model was established by considering film slip flow, wall temperature jump, foil deformation, and gas viscosity-temperature thermal effects. The variations in the lubrication performance of the foil cylindrical gas film seal with changes in shaft misalignment directions, misalignment angles, and operating parameters were investigated. The speed slip leads to a decrease in gas film lift and an increase in leakage. The wall temperature jump phenomenon caused by speed slip leads to a 2.56% decrease in film temperature. The shaft misalignment angles on the high-pressure and low-pressure sides have different impacts on the flow field, with film pressure and temperature differing by 66.78% and 11.19%, respectively.

Study on the excess seeds removing performance of a potato precision seed metering device

AbstractIn the potato mechanical planting industry, the high multi-seeding rate and miss-seeding rate are problems that exist in many potato precision seed metering devices. The main potato seeds in China are cut potatoes with different shapes and sizes. However, there is a lack of research on precision seeding technology for cut potatoes, and the adaptability of many existing potato seeding devices on cut potato is poor. The mechanized precision seeding of potato can effectively reduce labor consumption, improve the seeding effect (decrease multi-seeding rate and miss-seeding rate), improve the improve production of potato per acre and improve the quality commodity potatoes. In response to the above issues, a precision seed metering device with novel scoops, which can adapt to various sizes and shapes of cut potatoes, was developed. In this study, the different seed collecting scenarios (SCSs) were constructed. Through the statics and kinematic analysis, the excess seeds removing (ESR) process was divided in to three areas. The kinematic model of seed potato was established to study the influence of different SCSs and sprocket rotational speeds on the ESR performance, and preliminary determined the appropriate sprocket rotational speed range for ESR process. Then, the coupled simulation results of EDEM and RecurDyn revealed that different sprocket speeds and SCSs had a significant influence on the ESR performance. Finally, the bench tests and field tests were conducted to verify the actual performance of the precision seed metering device. The results showed that, with the increase of the sprocket rotational speed, the ESR performance of the device improved, the multi-seeding rate significantly decreased, but the miss-seeding rate increased. High sprocket rotational speed will remove more seed potatoes and cause high miss-seeding rate. The bench tests showed the appropriate sprocket rotational speed for medium and large potato was 35 r/ min. The field tests obtained the best qualified-seeding rate of 91.54%, the miss-seeding rate of 3.08% and the multi-seeding rate of 5.38%. This study can provide theoretical reference for the design of potato precision seed metering device.

Impact of Ion Migration on the Performance and Stability of Perovskite‐Based Tandem Solar Cells

AbstractThe stability of perovskite‐based tandem solar cells (TSCs) is the last major scientific/technical challenge to be overcome before commercialization. Understanding the impact of mobile ions on the TSC performance is key to minimizing degradation. Here, a comprehensive study that combines an experimental analysis of ionic losses in Si/perovskite and all‐perovskite TSCs using scan‐rate‐dependent current–voltage (J–V) measurements with drift‐diffusion simulations is presented. The findings demonstrate that mobile ions have a significant influence on the tandem cell performance lowering the ion‐freeze power conversion efficiency from >31% for Si/perovskite and >30% for all‐perovskite tandems to ≈28% in steady‐state. Moreover, the ions cause a substantial hysteresis in Si/perovskite TSCs at high scan speeds (400 s−1), and significantly influence the performance degradation of both devices through internal field screening. Additionally, for all‐perovskite tandems, subcell‐dominated J–V characterization reveals more pronounced ionic losses in the wide‐bandgap subcell during aging, which is attributed to its tendency for halide segregation. This work provides valuable insights into ionic losses in perovskite‐based TSCs which helps to separate ion migration‐related degradation modes from other degradation mechanisms and guides targeted interventions for enhanced subcell efficiency and stability.

Investigation of Critical Aspects of Roughness Assessment for Airfield Pavements

One of the main priorities of airport authorities is to maintain a high level of serviceability of runway pavements due to the high safety requirements for aircraft at high speeds. Accordingly, the assessment of the functional condition of airfield pavements is crucial for the proper operation of an airport. The most critical functional parameter appears to be pavement roughness. It characterizes the condition of the runway surface and is directly related to the safety of aircraft flights, as it affects the handling characteristics and braking performance of the aircraft, the increase in operating costs, and the wear of the aircraft. Worldwide, there are several indices for assessing the roughness of airfield pavements. This study aims to compare some of these indices to assess their ability to capture the characteristics of airfield pavement roughness. For this purpose, roughness data were collected along a runway with flexible pavement at a regional airport in southeast Europe and corresponding indices were estimated. The analysis of the data leads to the most efficient index for assessing the roughness of airfield surfaces to date. However, the need for a new index that expresses the response of the aircraft remains a critical issue.

A Review of Non-Destructive Raman Spectroscopy and Chemometric Techniques in the Analysis of Cultural Heritage

Today, there is an increasing concern and effort for protection, conservation, and restoration of cultural heritage materials. Non-invasive analytical methodologies such as Raman spectroscopy offers various advantages such as high speed, robust identification, low cost, and in-site analysis. Previous contributions highlighted the potential of Raman spectroscopy combined with multivariate statistics for identification and quality evaluation of cultural heritage materials such as paints, fiber, dyes, woods, stones, inks, and textile materials. Especially, application of chemometrics and multivariate statistics algorithms opens new horizons for scientists and inspectors. In conclusion, the paper provided an overview of the state-of-the-art uses of multivariate statistically equipped Raman spectroscopy methods for evaluation of cultural heritage and art materials with illustrations from previous research studies.

Influence of the geometric parameters of the connecting pipeline on the stiffness and damping of the pneumatic spring suspension at high-speed rolling stock

The study presents investigation is the pneumatic spring suspension system of diesel train DPKr-3. The research aims to estimate the influence of track irregularities on the pneumatic spring dynamic stiffness and its damping coefficient at 170–250 km/h speeds. The pneumatic spring suspension system characteristics were studied using an improved mathematical model of the system ‘rolling stock-track’. The pneumatic spring ‘force-strain’ relations are obtained at different values of the connecting pipeline diameter and length at high speeds. It was determined that increasing a connecting pipeline diameter from 20 to 40 mm and a speed change from 170 to 250 km/h causes decreasing a spring dynamic stiffness. It is shown that at a speed range from 170 to 250 km/h and a connecting pipeline diameter from 20 to 40 mm, a change in a pipeline length from 3 to 6 m does not lead to significant changes in stiffness. It was found that in the range of speeds from 170 to 250 km/h, the damping coefficient has maximum values with a diameter of the connecting pipeline from 25 to 30 mm.

QCMOS Detectors and the Case of Hypothetical Primordial Black Holes in the Solar System, near Earth Objects, Transients, and Other High-cadence Observations

Abstract Recent progress with CMOS detector development has opened new parameter space for high cadence time resolved imaging of transients and fast proper motion solar system objects. Using computer simulations for a ground-based 1.23 m telescope, this research note illustrates the gain of a new generation of fast readout low noise qCMOS sensors over CCDs and makes the case for high precision monitoring of asteroid orbits that can potentially shed light on the hypothetical existence of low mass primordial black holes, as well as for other applications requiring high speed imaging.

THE POTENTIAL OF ARTIFICIAL INTELLIGENCE IN MEDICINE

This article analyzes the prospects for using artificial intelligence (AI) in the medical field. It highlights that AI has already become an integral part of modern life and is actively utilized in various countries, particularly in diagnosis, treatment, and disease prognosis. AI enhances diagnostic accuracy, accelerates treatment processes, and optimizes medical resources significantly. Internationally, AI-based solutions are already widely implemented in countries like the USA, Japan, and China to improve healthcare services. These technologies allow doctors to process large amounts of data efficiently and perform complex procedures with reduced time and effort. However, in Ukraine, the development of AI technologies remains in its early stages, despite the approval of the “Concept for the Development of Artificial Intelligence” in 2020. The main challenges include the need to improve the legal framework, ensure data protection, and address ethical concerns. The use of AI can significantly enhance the quality of medical services while saving time and resources in healthcare institutions. In medical practice, AI is applied in several areas. For instance, AI accelerates diagnosis and improves accuracy, such as in the continuous monitoring of bone tissue in periodontal diseases; AI can analyze medical images with high speed and precision, identifying anomalies and leading to more accurate and timely diagnoses at early stages; AI algorithms can predict the deterioration of a patient’s condition by analyzing their medical data.

Morphy: A Compliant and Morphologically Aware Flying Robot

This study introduces a novel compliant and morphologically aware aerial robot called Morphy. The system is small (primary dimension 25.2 cm), lightweight (260 g), and agile (thrust‐to‐weight ratio of 3.3) while simultaneously integrating sensorized flexible joints in its arms. These elastic joints unlock the potential of experiencing flexible deformations, thus enabling the robot to resiliently withstand collisions at high speeds and squeeze through openings more narrow than its nominal dimensions. Extensive analysis of the flexible joints’ behavior under static loads and in free flight is conducted. Driven by the deformations that the robot can experience, adaptive control allocation exploiting real‐time angle deflection feedback from Hall‐effect sensors embedded in the joints is proposed and combined with fixed‐gain control. To demonstrate Morphy's performance, multiple experiments are conducted, including free flight trajectory tracking, impacts with the environment, and flying through narrow passages. As shown, the system can withstand collisions up to 7.6 m s−1 in drop tests and 3 m s−1 midflight while recovering back to hover. Finally, Morphy's capability to passively change its shape and squeeze through openings smaller than its nominal size is showcased both in the horizontal and in the vertical directions.

Case Study of an Integrated Design and Technical Concept for a Scalable Hyperloop System

This paper presents the design process and resulting technical concept for an integrated hyperloop system, aimed at realizing efficient high-speed ground transportation. This study integrates various functions into a coherent and technically feasible solution, with key design decisions that optimize performance and cost-efficiency. An iterative design process with domain-specific experts, regular reviews, and a dataset with a single source of truth were employed to ensure continuous and collective progress. The proposed hyperloop system features a maximum speed of 600 kmh and a capacity of 21 passengers per pod (vehicle). It employs air docks for efficient boarding, electromagnetic suspension (EMS) combined with electrodynamic suspension (EDS) for high-speed lane switching, and short stator motor technology for propulsion. Cooling is managed through water evaporation at an operating pressure of 10 mbar, while a 300 kW inductive power supply (IPS) provides onboard power. The design includes a safety system that avoids emergency exits along the track and utilizes separated safety-critical and high-bandwidth communication. With prefabricated concrete parts used for the tube, construction costs can be reduced and scalability improved. A dimensioned cross-sectional drawing, as well as a preliminary pod mass budget and station layout, are provided, highlighting critical technical systems and their interactions. Calculations of energy consumption per passenger kilometer, accounting for all functions, demonstrate a distinct advantage over existing modes of transportation, achieving greater efficiency even at high speeds and with smaller vehicle sizes. This work demonstrates the potential of a well-integrated hyperloop system to significantly enhance transportation efficiency and sustainability, positioning it as a promising extension to existing modes of travel. The findings offer a solid framework for future hyperloop development, encouraging further research, standardization efforts, and public dissemination for continued advancements.

Harnessing the Distributed Computing Paradigm for Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy allows fast and versatile elemental analysis, standing as a promising technique for a wide range of applications both at the research and industry levels. Yet, its high operation speed comes with a high throughput of data, which introduces some challenges at the level of the data processing domain, mainly due to the large computational load and data volume. In this work, we analyze and discuss opportunities of distributed computing paradigms and resources to address some of these challenges, covering most of the procedures usually employed in typical applications. We infer the possible impact of such computing resources by presenting some metrics of simple processing prototypes running in state-of-the-art computing facilities. Our results allow us to conclude that, while underexplored so far, these computing resources may allow for the development of tools for timely research and analysis in demanding applications and introduce novel solutions toward a more agile working environment.

Comparison of CNN-Based Architectures for Detection of Different Object Classes

(1) Background: Detecting people and technical objects in various situations, such as natural disasters and warfare, is critical to search and rescue operations and the safety of civilians. A fast and accurate detection of people and equipment can significantly increase the effectiveness of search and rescue missions and provide timely assistance to people. Computer vision and deep learning technologies play a key role in detecting the required objects due to their ability to analyze big volumes of visual data in real-time. (2) Methods: The performance of the neural networks such as You Only Look Once (YOLO) v4-v8, Faster R-CNN, Single Shot MultiBox Detector (SSD), and EfficientDet has been analyzed using COCO2017, SARD, SeaDronesSee, and VisDrone2019 datasets. The main metrics for comparison were mAP, Precision, Recall, F1-Score, and the ability of the neural network to work in real-time. (3) Results: The most important metrics for evaluating the efficiency and performance of models for a given task are accuracy (mAP), F1-Score, and processing speed (FPS). These metrics allow us to evaluate both the accuracy of object recognition and the ability to use the models in real-world environments where high processing speed is important. (4) Conclusion: Although different neural networks perform better on certain types of metrics, YOLO outperforms them on all metrics, showing the best results of mAP-0.88, F1-0.88, and FPS-48, so the focus was on these models.

Magnetic proximity-induced anomalous Hall effect in 2D CrOCl/Pt heterostructure

Two-dimensional (2D) van der Waals antiferromagnetic (AFM) materials boast exceptional properties for spintronics, including high spin-wave speeds and negligible stray fields. Their layer-by-layer assembly into heterostructures enables the exploration of next-generation spintronic devices. However, most 2D AFM materials are semiconductors or insulators. Thus, magneto-transport, a key segment of spintronics, is difficult to obtain especially at low temperatures. Herein, we report the observation of anomalous Hall effect (AHE) in 2D CrOCl/Pt bilayer heterostructure. Magneto-transport measurements supported by density functional theory calculations reveal that the appearance of AHE is generated by spin polarization in Pt due to the magnetic proximity effect. In addition, it is demonstrated that the magnetic easy-axis changes from the z-axis to the xy-plane at the interface of the heterostructure. Our work sheds light on the magneto-transport properties of 2D CrOCl and its potential in emerging spintronic devices.

Efficiency of high speed spur gears with an isotropic superfinishing

Efficiency of high speed spur gears with an isotropic superfinishing

Enhancing Acceleration Capabilities in Professional Women’s Football Players: A Comparative Analysis of Game-Based Versus Resisted Sprint Trainings

The recognition of high-speed demands in football has led elite academies to prioritize acceleration capabilities for player selection and promotion, particularly given their fundamental role in the motor skills of professional players and their impact on goal-related opportunities. This study explored the effectiveness of game-based versus resisted sprint training methods in enhancing the acceleration abilities of professional women’s football players. Over the entire competitive period, the training load of 26 athletes (24.2 ± 3.7 years) was assessed using GPS devices, and sprint capabilities were evaluated through four 30-m acceleration tests spaced six weeks apart. Linear mixed models (LMMs) analyzed physical load parameters, including distance covered at high speeds, speed events, and maximum speed, with periods and players as fixed and random effects, respectively. Significant sprint performance improvements were observed across all intervals, particularly when high-intensity distance volumes were combined with resisted sprint training. Conversely, high-intensity running without additional stimuli also led to performance gains, albeit to a lesser extent. Both game-based and resisted sprint training methods were effective in enhancing acceleration capabilities, while the absence of specific sprint focus did not significantly alter sprint performance. These findings support the inclusion of tailored sprint training in athletic programs to optimize acceleration in women’s football players.

Effect of Geometric Parameters of High-Speed Helical Gears on Friction Flash Temperature and Scuffing Load Capacity in Electric Vehicles

High-speed reducers in electric vehicles, characterized by high rotation speeds, heavy loads, large helix angles, and high contact ratios, are prone to tooth surface scuffing due to high sliding speeds. This scuffing is caused by adhesion wear from excessive instantaneous friction flash temperatures. The prevailing approach to gear scuffing analysis relies on the standard formula method, which is a relatively rudimentary technique. This method lacks the precision required to accurately assess the intricate distribution of tooth surface flash temperature (TSFT), limiting its efficacy in targeted tooth optimization. This study introduces an enhanced semi-analytical method to calculate TSFT and analyzes its variation under different conditions: increased tooth number and reduced module, altered pressure angle, and varied helix angle. The aim is to understand how these geometric parameters affect TSFT and the scuffing load capacity of high-speed reducer gears. This study calculates load distribution and TSFT under peak operating conditions and shows that increasing the tooth number, pressure angle, and helix angle can reduce maximum TSFT by more than 30%, improving scuffing safety and load capacity. However, these improvements must consider the gear’s allowable bending safety factor and bearing service life. The research concludes that optimizing these geometric parameters can significantly enhance the scuffing load capacity of gearsets.