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Image‐based measurements of underwater infrastructure dynamics is challenging due to the refractive nature of the environment. To mitigate this problem, a multimedia high‐speed videogrammetric technique is proposed. The approach monitors the motion states of the underwater object and introduces a virtual refracting interface compensation model. The spatial expression of the virtual refracting interface is first found as a convex surface. Through the proposed compensation model, the complex multimedia refraction imaging can be easily transformed to simple dual‐media refraction imaging. Combined with high‐speed videogrammetry, this multimedia imaging analysis approach can measure underwater deformation. Simulated and experimental testing confirmed the feasibility and reliability of the proposed approach with sub‐millimetre positioning accuracy. [ABSTRACT FROM AUTHOR]

Background Purpose Methods Results Conclusions Physical vascular phantoms are instrumental in studying intracranial aneurysms and testing relevant imaging tools and training systems to provide improved clinical care. Current vascular phantom production methods have major limitations in capturing the biophysical and morphological characteristics of intracranial aneurysms with good fidelity and multi‐modal imaging capacity. With stereolithography (SLA) 3D printing technology becoming more accessible, newer flexible and transparent printing materials with higher precision controls open the door for improving the efficiency and quality of producing anthropomorphic vascular phantoms but have rarely been explored for the application.This technical note intends to report the feasibility of using SLA 3D printing technology to manufacture flexible intracranial aneurysm phantoms with similar scales to the real anatomy, as well as their capacity for multi‐modal flow imaging and analysis, including ultrasound flow imaging, high‐speed filming, and particle image velocimetry analysis.We designed and 3D‐printed two intracranial aneurysm phantoms with an SLA 3D printer using Formlabs Elastic 50A resin. By using a micropump to introduce cyclical flows in the phantoms, we first employed conventional Doppler and vector flow ultrasonography to observe and measure different fluidic properties. Then, a high‐speed camera was used to record particles flowing within the phantom, and we further conducted a particle image velocimetry analysis, including the distribution of mean 2D velocity vectors, average velocity magnitudes, and the mean vorticity fields in the phantom for the high‐speed imaging data.We successfully 3D‐printed flexible intracranial aneurysm phantoms with similar dimensions to the real anatomy. Additionally, we validated the phantoms’ ability to allow visualization, measurement, and analysis of flow dynamics based on both real‐time ultrasound and optical imaging.Our proof‐of‐concept study illustrates that SLA 3D printing using commercial elastic resins can significantly contribute towards facilitating the fabrication of flexible intracranial aneurysms phantoms for training, research, and preoperative planning. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Spray systems in agriculture serve essential roles in the precision application of pesticides, fertilizers, and water, contributing to effective pest control, nutrient management, and irrigation. These systems enhance efficiency, reduce labor, and promote environmentally friendly practices by minimizing chemical waste and runoff. The efficacy of a spray is largely determined by the characteristics of its droplets, including their size and velocity. These parameters are not only pivotal in assessing spray retention, i.e., how much of the spray adheres to crops versus becoming environmental runoff, but also in understanding spray drift dynamics. This study introduces a real-time deep learning-based approach for droplet detection and tracking which significantly improves the accuracy and efficiency of measuring these droplet properties. Our methodology leverages advanced AI techniques to overcome the limitations of previous tracking frameworks, employing three novel deep learning-based tracking methods. These methods are adept at handling challenges such as droplet occlusion and varying velocities, ensuring precise tracking in real-time potentially on mobile platforms. The use of a high-speed camera operating at 2000 frames per second coupled with innovative automatic annotation tools enables the creation of a large and accurately labeled droplet dataset for training and evaluation. The core of our framework lies in the ability to track droplets across frames, associating them temporally despite changes in appearance or occlusions. We utilize metrics including Multiple Object Tracking Accuracy (MOTA) and Multiple Object Tracking Precision (MOTP) to quantify the tracking algorithm's performance. Our approach is set to pave the way for innovations in agricultural spraying systems, offering a more efficient, accurate, and environmentally responsible method of applying sprays and representing a significant step toward sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During the laser directed energy deposition (LDED) process, the in-flight thermal dynamics of metal powders lead to the formation of detrimental by-products such as fumes, flames, and metal vapors. In this work, we use a high-speed camera to investigate the nuanced thermal stage changes of the powders, examining how gas flow rates and laser beam powers influence them. We identify distinct stages in the powder's journey: heating up, fusion and vaporization, flaming, tailing, and accelerated falling. Notably, the latter stages adversely affect both the processing environment and surface quality. Control over gas flow rate and laser beam power dictates the trajectory, duration, and intensity of tailing. Additionally, laser irradiation accelerates the falling speed of particles by 6.8–22.8% compared to non-irradiated ones. Higher laser beam powers increase vaporization-induced propulsion, culminating in escalated particle velocities. Optimal gas flow rates enhance the surface quality by significantly minimizing high-temperature spatter. Through this work, the in-flight thermal dynamic behaviors of metal particles and their impact on LDED processing are explained.

Invasive plant species pose ecological threats to native ecosystems, particularly in areas adjacent to roadways, considering that roadways represent lengthy corridors through which invasive species can propagate. Traditional manual survey methods for monitoring invasive plants are labor-intensive and limited in coverage. This paper introduces a high-speed camera system, named CamAlien, designed to be mounted on vehicles for efficient invasive plant species monitoring along roadways. The camera system captures high-quality images at rapid intervals, to monitor the full roadside when following traffic speed. The system utilizes a global shutter sensor to reduce distortion and geotagging for precise localistion. The camera system makes it possible to collect extensive data sets, which can be used for a digital library of the invasive species and their locations, but also subsequent training of machine learning algorithms for automated species recognition.

The Event‐based Vision Sensor (EVS) is a bio‐inspired sensor that captures detailed motions of objects, aiming to become the 'eyes' of machines like self‐driving cars. Compared to conventional frame‐based image sensors, the EVS has an extremely fast motion capture equivalent to 10,000‐fps even with standard optical settings, plus high dynamic ranges for brightness and also lower consumption of memory and energy. Here, we developed 22 characteristic features for analysing the motions of aquatic particles from the EVS raw data and tested the applicability of the EVS in analysing plankton behaviour. Laboratory cultures of six species of zooplankton and phytoplankton were observed, confirming species‐specific motion periodicities up to 41 Hz. We applied machine learning to automatically classify particles into four categories of zooplankton and passive particles, achieving an accuracy up to 86%. At the in situ deployment of the EVS at the bottom of Lake Biwa, several particles exhibiting distinct cumulative trajectory with periodicities in their motion (up to 16 Hz) were identified, suggesting that they were living organisms with rhythmic behaviour. We also used the EVS in the deep sea, observing particles with active motion and periodicities over 40 Hz. Our application of the EVS, especially focusing on its millisecond‐scale temporal resolution and wide dynamic range, provides a new avenue to investigate organismal behaviour characterised by rapid and periodical motions. The EVS will likely be applicable in the near future for the automated monitoring of plankton behaviour by edge computing on autonomous floats, as well as quantifying rapid cellular‐level activities under microscopy. [ABSTRACT FROM AUTHOR]

In this study, underwater explosion tests with 2.5 g trinitrotoluene explosive under different fixed plates with prefabricated holes were conducted. The experimental results showed that the air inflow from the prefabricated hole caused the bubble to collapse earlier with an increase in the hole diameter. In addition, the deformation mode of the thin plate transitioned from "convex" to "concave" (up to down). Next, the coupled Eulerian-Lagrangian method was used to perform the corresponding numerical simulation. The accuracy of the numerical simulation method was verified through a comparison with the experimental data. In addition, a series of numerical simulations were conducted with different prefabricated-hole diameters, blast distances, and prefabricated-hole shapes. The results showed that the bubble-pulsating water jet substantially influenced the deformation of the thin plate when the diameter of the prefabricated hole was within the theoretical maximum bubble radius. When the blast distance was within the theoretical maximum bubble radius, the thin plate was subjected to only a single bubble pulsation owing to the air inflow from the prefabricated hole. [ABSTRACT FROM AUTHOR]

To study the fracture speed of power turbine blades in aero-engine and its variation law with the proportion of bending stress, a total of 32 simulated blades with 4 different ratios of bending stress were designed and processed based on the principle of equivalence. The fracture speed of the simulated blades was calculated by finite element method. The simulated blades were grouped and fracture speed measurement experiments were conducted to obtain the actual fracture speed and fracture form of the blades. The simulated blade fracture test process was recorded by high-speed camera technology, and the variation law of blade fracture speed with the proportion of blade bending stress was obtained. The research results show that the error between the actual fracture speed and the calculated speed of the simulated blades are not greater than 1. 10%. Within a certain range, as the bending stress decreases, the fracture speed of the blade generally shows a downward trend, and as the proportion of bending stress in the blade increases, the fracture speed of the blade decreases faster. The research provides a reference for the strength design and blade fracture test methods of real blades, which has important engineering application value. [ABSTRACT FROM AUTHOR]

In this study, a stable and high-speed vision-based self-position estimation method was proposed that improves upon the existing method of lane detection by recognizing the lighting facilities that are installed in tunnels on Japanese expressways where GNSS cannot be used. In addition, we proposed a method for inspecting multiple cracks at once by estimating the self-position with the successful rate 75% in the traveling direction by counting the lighting with the successful rate 99.85%. The effectiveness of the method was verified by capturing images of cracks in an actual tunnel. The proposed method will enable more frequent inspections for tunnel cracks that lead to flaking while maintaining infrastructure safety, reducing costs, and improving tunnel visual inspection flow efficiency. [ABSTRACT FROM AUTHOR]

Invasive plant species pose ecological threats to native ecosystems, particularly in areas adjacent to roadways, considering that roadways represent lengthy corridors through which invasive species can propagate. Traditional manual survey methods for monitoring invasive plants are labor-intensive and limited in coverage. This paper introduces a high-speed camera system, named CamAlien, designed to be mounted on vehicles for efficient invasive plant species monitoring along roadways. The camera system captures high-quality images at rapid intervals, to monitor the full roadside when following traffic speed. The system utilizes a global shutter sensor to reduce distortion and geotagging for precise localistion. The camera system makes it possible to collect extensive data sets, which can be used for a digital library of the invasive species and their locations, but also subsequent training of machine learning algorithms for automated species recognition.

This work investigates the effectiveness of using convolutional neural networks (CNNs) and instantaneous displacement measurements for damage identification in beams. The study involves subjecting laboratory beams to eight distinct damage scenarios and capturing the vertical positions of 60 points along the beam length during free-vibration tests using a high-speed camera. The data obtained was subsequently used to train a CNN in a supervised manner to estimate the level of damage at each point. Results showed that the CNN models were able to correctly localize and quantify the damage levels when trained on data from all damage scenarios. The soundness of the proposed methodology was demonstrated in a robustness assessment, where all eight damage scenarios were correctly identified even when two of them were excluded from the training dataset. [ABSTRACT FROM AUTHOR]

Copyright of Problems of Mechatronics. Armament, Aviation, Safety Engineering / Problemy Mechatroniki. Uzbrojenie, lotnictwo, Inżynieria Bezpieczeństwa is the property of Index Copernicus International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pellet ablation mechanism is an interesting subject for plasma fuelling in fusion plasmas. In GAMMA 10/PDX, pellet injection experiments for higher density plasma production are planned to conduct detached plasma experiments in the higher density plasma condition. We measured the pellet ablation cloud by using the two-directional simultaneous photography system in GAMMA 10/PDX. The tomography reconstruction technique was used for considering the pellet trajectory in the plasma and pellet ablation. The three-dimensional pellet trajectory and pellet ablation images in the plasma were clearly obtained for the first time, to the best of our knowledge. [ABSTRACT FROM AUTHOR]

Abstract The Event‐based Vision Sensor (EVS) is a bio‐inspired sensor that captures detailed motions of objects, aiming to become the ‘eyes’ of machines like self‐driving cars. Compared to conventional frame‐based image sensors, the EVS has an extremely fast motion capture equivalent to 10,000‐fps even with standard optical settings, plus high dynamic ranges for brightness and also lower consumption of memory and energy. Here, we developed 22 characteristic features for analysing the motions of aquatic particles from the EVS raw data and tested the applicability of the EVS in analysing plankton behaviour. Laboratory cultures of six species of zooplankton and phytoplankton were observed, confirming species‐specific motion periodicities up to 41 Hz. We applied machine learning to automatically classify particles into four categories of zooplankton and passive particles, achieving an accuracy up to 86%. At the in situ deployment of the EVS at the bottom of Lake Biwa, several particles exhibiting distinct cumulative trajectory with periodicities in their motion (up to 16 Hz) were identified, suggesting that they were living organisms with rhythmic behaviour. We also used the EVS in the deep sea, observing particles with active motion and periodicities over 40 Hz. Our application of the EVS, especially focusing on its millisecond‐scale temporal resolution and wide dynamic range, provides a new avenue to investigate organismal behaviour characterised by rapid and periodical motions. The EVS will likely be applicable in the near future for the automated monitoring of plankton behaviour by edge computing on autonomous floats, as well as quantifying rapid cellular‐level activities under microscopy.

Particle dampers (PD) can be embedded in structures fabricated via selective laser melting (SLM) because the raw powder (particle diameter : several tens of micrometers) remains in closed spaces during SLM. However, most PD studies have focused on coarse particle sizes larger than 1 mm and low frequencies below 100 Hz; there is insufficient evaluation of PD attenuation characteristics and particle behavior for particle sizes from tens of micrometers to sub-millimeters and in the 100 to 1000 Hz band. In this study, the equivalent viscous damping coefficients of spherical zirconia balls with nominal sizes of 0.05, 0.10, 0.20, and 0.40 mm are measured under different vibration accelerations (from 9 to 148 m/s2(rms)) and frequencies (from 100 to 800 Hz) to experimentally investigate the effect of fine particle diameters on the damping properties. It is deduced that in the frequency range above 200 Hz, the equivalent viscous damping coefficients of the coarse particle diameter are greater than those of fine particles at accelerations below the range of 15.7–22.4 m/s2(rms). In contrast, the equivalent viscous damping coefficients of the fine particles are greater than those of the coarse particles at accelerations above the 15.7–22.4 m/s2(rms) range. In addition, to determine the reason for these tendencies, the behavior of particles with a nominal size of 0.05 mm, which is close to the raw powder, is observed through a window using a high-speed microscope camera. The results reveal that in the low acceleration range, the inertial force does not overcome the static friction force owing to poor flowability caused by adhesion force, and the particles are always stationary with respect to the sealed container.

This study proposes a positive pressure re-acceleration assisted seeding mechanism and analyzes the motion mechanism of corn seeds during the seeding process. By employing the CFD-EDEM gas-solid coupling simulation analysis method, the fluid characteristics, initial ejection velocity of seeds, seed dropping time difference, and sowing position difference in the seeding mechanism under different structural parameters of the air pressure valve body were investigated. The optimal structural parameters of the air pressure valve body were determined (nozzle gap c = 0.6 mm, throat constriction diameter d = 16 mm, and throat constriction length l = 44 mm). A multi-factor experimental method was used to explore the effects of airflow pressure, forward speed during sowing, and sowing distance on sowing performance, aiming to identify the optimal working parameters for the positive pressure re-acceleration seeding mechanism. High-speed camera technology was used to record and analyze the seed movement process. The results indicate that an increase in positive pressure within the seed guide tube shortens the sowing time of corn seeds, reduces the coefficient of variation of seed dropping time difference, and effectively improves the consistency of sowing distance. The optimal parameters are a forward speed of 8 km/h, sowing distance of 20 cm, airflow pressure of 10 kPa, with a sowing distance coefficient of variation of 7.56%, and a seed dropping time difference coefficient of variation of 5.35%.

Spray systems in agriculture serve essential roles in the precision application of pesticides, fertilizers, and water, contributing to effective pest control, nutrient management, and irrigation. These systems enhance efficiency, reduce labor, and promote environmentally friendly practices by minimizing chemical waste and runoff. The efficacy of a spray is largely determined by the characteristics of its droplets, including their size and velocity. These parameters are not only pivotal in assessing spray retention, i.e., how much of the spray adheres to crops versus becoming environmental runoff, but also in understanding spray drift dynamics. This study introduces a real-time deep learning-based approach for droplet detection and tracking which significantly improves the accuracy and efficiency of measuring these droplet properties. Our methodology leverages advanced AI techniques to overcome the limitations of previous tracking frameworks, employing three novel deep learning-based tracking methods. These methods are adept at handling challenges such as droplet occlusion and varying velocities, ensuring precise tracking in real-time potentially on mobile platforms. The use of a high-speed camera operating at 2000 frames per second coupled with innovative automatic annotation tools enables the creation of a large and accurately labeled droplet dataset for training and evaluation. The core of our framework lies in the ability to track droplets across frames, associating them temporally despite changes in appearance or occlusions. We utilize metrics including Multiple Object Tracking Accuracy (MOTA) and Multiple Object Tracking Precision (MOTP) to quantify the tracking algorithm’s performance. Our approach is set to pave the way for innovations in agricultural spraying systems, offering a more efficient, accurate, and environmentally responsible method of applying sprays and representing a significant step toward sustainable agricultural practices.

Invasive plant species pose ecological threats to native ecosystems, particularly in areas adjacent to roadways, considering that roadways represent lengthy corridors through which invasive species can propagate. Traditional manual survey methods for monitoring invasive plants are labor-intensive and limited in coverage. This paper introduces a high-speed camera system, named CamAlien, designed to be mounted on vehicles for efficient invasive plant species monitoring along roadways. The camera system captures high-quality images at rapid intervals, to monitor the full roadside when following traffic speed. The system utilizes a global shutter sensor to reduce distortion and geotagging for precise localistion. The camera system makes it possible to collect extensive data sets, which can be used for a digital library of the invasive species and their locations, but also subsequent training of machine learning algorithms for automated species recognition.

In order to solve the problems of poor hole-filling performance and the high seed-breakage rate of conventional rice bud seed precision hole direct seed-metering devices, a side-filled rice precision hole direct seed-metering device was developed, and the mechanism and force analyses for seeding operations were carried out. The key factors affecting seeding quality were determined: rotation speed, seeding angle and seeding height. By coupling the discrete element method (DEM) and multi-rigid body dynamics (MBD), the seed breakage rate and seeding performance at different rotation speeds were analyzed. Single-factor bench testing was used to analyze the effect of a duckbill unit on seeding performance under different factor levels. The three-factor and five-level quadratic regression orthogonal rotation center combination test methods were used to obtain the optimal working parameter combination. The test results showed that when the rotation speed was 47 r/min, the seeding angle was 19°, and the seeding height was 180 mm, the qualified index of seeding was 92.03%, the hole diameter qualified index was 91.62%, and the hole distance variation index was 7.17%. This study provides a reference for the research of mechanical rice sprouting seed-metering devices. [ABSTRACT FROM AUTHOR]

This study was designed as a preliminary experiment for missions at the electrostatic levitation furnace in the International Space Station (ISS-ELF) such as Hetero-3D. The objective of this study was to employ a high-speed camera to determine the recalescence time of undercooled Ti6Al4V alloy with TiC heterogeneous nucleation site particles more accurately compared to measurements using a pyrometer. The sample was melted and solidified in the ground-based electrostatic levitation (ESL) furnace. The changes in the luminescence emitted from the sample surface due to recalescence were recorded using a high-speed camera, and the intensity at the center of each captured image was analyzed with MATLAB® software. As a result, the intensity of the undercooled samples increased significantly during recalescence. The maximum change in the intensity was 101 per 256 gray levels in the recording at 7,200 frames per second (fps) and the noise was at most only 3. Therefore, the recalescence time could be obtained using the high-speed camera. At 15,000 fps, the recalescence time was within 6.7 × 10-5 s, which was much more accurate than the time (0.11 s) measured using a pyrometer at a sampling rate of 120 Hz in the ESL furnace. For enhanced measurement accuracy, it is crucial to establish an appropriate exposure time to prevent the intensity from reaching the lower limit of 0 just before recalescence and the upper limit of 255 immediately after that. This study suggests that the high-speed camera newly installed in the ISS-ELF in 2023 may have the potential to achieve a more accurate recalescence time than the pyrometer at a sampling rate of 100 Hz in the ISS-ELF. [ABSTRACT FROM AUTHOR]

Invasive plant species pose ecological threats to native ecosystems, particularly in areas adjacent to roadways, considering that roadways represent lengthy corridors through which invasive species can propagate. Traditional manual survey methods for monitoring invasive plants are labor-intensive and limited in coverage. This paper introduces a high-speed camera system, named CamAlien, designed to be mounted on vehicles for efficient invasive plant species monitoring along roadways. The camera system captures high-quality images at rapid intervals, to monitor the full roadside when following traffic speed. The system utilizes a global shutter sensor to reduce distortion and geotagging for precise localistion. The camera system makes it possible to collect extensive data sets, which can be used for a digital library of the invasive species and their locations, but also subsequent training of machine learning algorithms for automated species recognition.

In order to solve the problems of poor hole-filling performance and the high seed-breakage rate of conventional rice bud seed precision hole direct seed-metering devices, a side-filled rice precision hole direct seed-metering device was developed, and the mechanism and force analyses for seeding operations were carried out. The key factors affecting seeding quality were determined: rotation speed, seeding angle and seeding height. By coupling the discrete element method (DEM) and multi-rigid body dynamics (MBD), the seed breakage rate and seeding performance at different rotation speeds were analyzed. Single-factor bench testing was used to analyze the effect of a duckbill unit on seeding performance under different factor levels. The three-factor and five-level quadratic regression orthogonal rotation center combination test methods were used to obtain the optimal working parameter combination. The test results showed that when the rotation speed was 47 r/min, the seeding angle was 19°, and the seeding height was 180 mm, the qualified index of seeding was 92.03%, the hole diameter qualified index was 91.62%, and the hole distance variation index was 7.17%. This study provides a reference for the research of mechanical rice sprouting seed-metering devices.

• Instantaneous unloading experiments were conducted on clastic rock. • Real-time crack evolution on the σ 2 face captured by high-speed camera. • Instantaneous unloading induces severe and irreversible lateral dilation. • Two distinct fracture zones observed: tensile and tensile-shear mixed fracture zones. • Cracking mechanism induced by blasting excavation in deep clastic rock was revealed. The cracking and squeezing problem in deep engineering significantly constrains project construction. To reveal the cracking mechanism of rock under instantaneous unloading, a self-designed rigid true triaxial experimental apparatus, equipped with groundbreaking electromagnetic unloading and high-speed camera functions, was utilized to conduct instantaneous unloading tests on clastic rock with varied levels of initial damage. The results indicate that samples undergo severe and irreversible lateral dilation during instantaneous unloading, with dilational strain rapidly increasing at higher initial damage levels. Instantaneous unloading induces the generation of numerous tensile microcracks, which propagate and coalesce rapidly. The crack propagation speed, as well as the length and width of the cracks at failure, increase with the rise of the initial damage level. The samples eventually exhibit two distinct macroscopic fracture zones: a tensile fracture zone and a tensile-shear mixed fracture zone. Analysis of acoustic emission hits and energy indicates that higher initial damage levels correspond to greater unloading damage, with a higher overall proportion of tensile cracks throughout the experiment. Under the induction of blasting excavation, radial stress is rapidly unloaded, and dense tensile cracks emerge in the immediate surrounding rock, leading to cracking and squeezing towards the free face. Importantly, higher initial damage levels intensify the squeezing effect. The self-developed equipment serves as a crucial technical tool for researching excavation unloading, and the insights derived from this study provide valuable guidance for understanding cracking mechanisms and informing the construction of deep engineering projects. [ABSTRACT FROM AUTHOR]

• A multi-sensor system is applied to capture signals during laser hot wire cladding with a high-power direct diode laser. • Sensor responses to varying substrate surface conditions, substrate thicknesses, laser powers, and scanning speeds are analyzed. • Relationship among the detected signals, geometry characteristics of clad layer, surface roughness, dilution depth, and microhardness are established. A multi-sensor online monitoring system, including a high-speed camera, a spectrometer, and an infrared camera, was developed to enhance the laser hot wire cladding process. This innovative process feeds a preheated wire, using a hot-wire power supply, into a shallow molten pool formed on the substrate surface by a rectangular diode laser beam. This study assesses the capability of the monitoring system to detect variations in cladding process conditions that significantly influence the geometry and quality of the clad layer. Specifically, the study involved four sets of laser hot-wire cladding experiments, altering substrate surface conditions, substrate thicknesses, laser powers, and scanning speeds. The real-time data from the three sensors were synchronized and analyzed in depth, focusing on the morphology and microhardness of the clad layers. A laser vision sensor was employed to examine the surface profile and roughness of the clads. The findings indicated that the crucial role of surface preparation in influencing the dynamics of the molten pool, subsequently affecting the geometry, dilution depth, and microhardness of the clads. The sensors demonstrated increased sensitivity to changes in surface conditions compared to variations in other conditions like substrate thickness, laser power, and scanning speed. A significant correlation was found between the dilution depth, clad height, surface roughness, and microhardness of the clad layer. These correlations are in response to adjustments in laser power, scanning speed, and surface preparation and can be reliably and rapidly detected by the multi-sensor system. [ABSTRACT FROM AUTHOR]

Conventional drying methods for water-containing porous particles typically require overcoming the latent heat of water evaporation, rendering them energy intensive. We present a rapid drying process via a cyclone below the boiling point on the basis of high-speed self-rotation and microchannel oscillation of particles. A high-speed camera recorded the particle revolution and self-rotation speeds within the cyclone, which allowed us to calculate the centrifugal acceleration of water in the particle pores, which reached 23,766 m/s² and periodically oscillated. Consequently, water in macropore with diameters larger than 8.1 μm can be separated into microdroplets by cyclones. Various factors influencing the drying efficiency of the cyclone were investigated at the laboratory scale. In experiments conducted with an airflow rate of 75 m³/h, an air temperature of 80°C, and a particle feed rate of 5.4 kg/h, a significant reduction in the water content was observed, with the water content decreasing from 68.2 % to 32.1 % within only 25 s. Compared with traditional evaporative drying, the drying process via a cyclone for aluminum hydroxide with a capacity of 2.4 tons/day saves 2500 tons of steam and 70,000 kW•h of electricity per year, resulting in a cost reduction of 560,000 CNY. These findings suggest that cyclone drying is a highly efficient and cost-effective method for drying water-containing porous particles, with significant implications for energy savings and sustainability in industrial applications. [Display omitted] • Aluminum hydroxide drying technology was developed based on cyclone. • Water in the particle macropores can be separated in the form of microdroplets. • Efficient drying was achieved at low temperature (80 °C) in 25 seconds. • Drying process with a capacity of 2.4 t/d can save 560,000 CNY/year. [ABSTRACT FROM AUTHOR]

Invasive plant species pose ecological threats to native ecosystems, particularly in areas adjacent to roadways, considering that roadways represent lengthy corridors through which invasive species can propagate. Traditional manual survey methods for monitoring invasive plants are labor-intensive and limited in coverage. This paper introduces a high-speed camera system, named CamAlien, designed to be mounted on vehicles for efficient invasive plant species monitoring along roadways. The camera system captures high-quality images at rapid intervals, to monitor the full roadside when following traffic speed. The system utilizes a global shutter sensor to reduce distortion and geotagging for precise localistion. The camera system makes it possible to collect extensive data sets, which can be used for a digital library of the invasive species and their locations, but also subsequent training of machine learning algorithms for automated species recognition., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Dyrmann M et al.)

To compare the applicability of different calculation methods for quantifying apple bruising under different experimental conditions, this study used the finite element method to evaluate the volume quantification method of bruising. Based on reverse engineering technology, an accurate 3D model of an apple was established and physical characteristic parameters were measured. The accuracy of the finite element models of the apple peel and flesh was verified from multiple angles, including drop state, velocity, and bruise surface area after collision, with a maximum error of 3.38%. The influence of drop height (600 mm, 900 mm, 1200 mm, 1500 mm, 1800 mm, and 2100 mm) and contact material (steel, resin, wood, and rubber) on bruise volume was analysed. Based on the results simulated by the finite element method, the accuracy of the bruise thickness method (BTM), the full depth method (FDM), the enclosed volume method (EVM), the unbruised volume removed method (UVRM) and the ellipsoid method (EM) were compared. The results show that the adaptability of each calculation method to the experimental conditions is different: the accuracy of estimating the volume of bruises is in the order of BTM > EM> UVRM > EVM > FDM (600 mm), FDM > EVM > UVRM > BTM > EM (900–1200 mm), BTM > EM > UVRM > EVM > FDM (1500–2100 mm), EM > BTM > UVRM > EVM > FDM (resin), BTM > EM > UVRM > EVM > FDM (steel, wood, and rubber). This study provides ideas for accurately determining the volume of fruit bruises and related simulation studies, and provides references for the adaptive selection of bruise calculation methods. [Display omitted] • An apple dual-layer model based on velocity and bruise area is verified. • The impact of height and contact materials on apple bruising is analyzed. • The bruise volume of apple is visually extracted. • The quantitative calculation methods for bruise volume is evaluated based on FEM. [ABSTRACT FROM AUTHOR]

The transient mixing dynamics of an initially segregated binary granular system in a half-filled rotating drum are experimentally investigated. The granular system consists of spherical beads having identical size. The density ratio between the two granular phases is 2.8. With its ability to scan three-dimensional opaque systems with a high frequency, the ultrafast X-ray computed tomography is used to capture the transient and steady-state segregation dynamics in the bulk. The segregation dynamics are also compared to those at the circular end-wall caps, which have been captured with a camera. The results show an axial migration of the denser particles towards the bulk and, more importantly, second-order overshooting dynamics in the radial mixing index, which tend to increase with the Froude number. The results will find application in industrial systems, where rapid mixing occurs. We also believe the presented data can serve as validation for future three-dimensional simulations focusing on the transient formation of segregation patterns in the bulk. [Display omitted] • Segregation core depends on kinetic energy and dynamic angle of repose • Overshooting radial mixing dynamics are associated with cascading flow • The response time associated with mixing index correlates with the Froude number • Transient segregation dynamics at the front cap are compared to those in the bulk [ABSTRACT FROM AUTHOR]

Dam-break-driven experimental tests are conducted to explore the intricate dynamics of water and sediment movement during a swash process. Utilizing a combined approach of a high-speed camera and an acoustic doppler velocity profiler, detailed records of flow velocity and sediment movements are captured. This study offers novel insights regarding flow shear stress, layer thickness and velocity of sediment transport in the backwash process, as well as behaviors of individual sand particles. Linear relationships serve to depict alterations in bed shear stress over time. The changing rate of bed shear stress can be influenced by the factors such as the beach slope, sediment grain size, and location on the beach. Increasing layer thickness of sediment transport corresponds with increasing outer layer velocity, exhibiting a linear-exponential relationship. A tentative interpretation of the inflection point (of linear and exponential relationship) designates it as a division between sheet load and a conjunction of sheet load and suspended load. With the onset of a bore and under the influence of turbulence and bubbles, sediment predominantly moves upwards, leading to sediment pickup. However, during both the late uprush phase and the backwash phase, the primary direction of sediment movement reverses downwards, favoring sediment settling. Empirical equations are formulated to estimate the parameters on the bed shear stress and the sediment transport layer. This study enhances understanding of water and sediment movement in swash processes, supplying validation data for numerical models. • The dynamics of water and sediment movement during a swash process are investigated through a series of flume tests driven by dam-break. • An analysis is performed on the factors that affect the changing rate of bed shear stress throughout the swash process. • The thickness of the sediment transport layer increases proportionately with outer layer velocity, demonstrating a linear-exponential relationship. • A thorough analysis is conducted on the behaviors of individual sediment particles, focusing on aspects such as moving direction and moving velocity. • Empirical equations are given to estimate parameters on the bed shear stress and the sediment transport layer. [ABSTRACT FROM AUTHOR]

• The spreading and splashing of the liquid film by inclined jet impingement were studied using high-speed cameras. • A unique liquid film deflection phenomenon is observed due to the boiling of the liquid film. • The splashing characteristics and mechanism of liquid film have been discussed. In this paper, the liquid film formed by inclined jet impingement on the vertical hot wall is investigated by a high-speed camera. The effects of the jet velocity (5.5 m/s ≤ u 0 ≤ 14.6 m/s, 3804 ≤ Re ≤ 10098) and initial wall temperature (25 ℃≤ T 0 ≤ 250 ℃) on the spreading and splashing of the liquid film are explored. Although the jet velocity and initial wall temperature have little effect on the spreading velocity of the liquid film, the wetting front position and liquid film area increase. For T 0 ≥ 150 ℃, a unique liquid film deflection phenomenon is observed due to the boiling of the liquid film, which results in a substantial amount of splashing. Based on the characteristics of the deflection splashing, three modes are categorized, i.e., annular splashing, banded splashing, and non-splashing. The splashing of the liquid film on the hot surface is owing to the rupture of boiling bubbles, the breakup of surface waves, and the liquid splashing in the boiling zone. The splashing rate of the liquid film is measured, and it is found that an increase in T 0 improves the splashing rate significantly, and the splashing rate even exceeds 70 % at T 0 = 250 °C. [ABSTRACT FROM AUTHOR]

The first point of contact between a spherical blood drop and a surface is related to the angle between the trajectory of the blood drop and the surface being struck. This angle is often referred to as the impact angle which can be estimated by knowing the width and length of the resultant elliptical bloodstain. Most software programs dedicated to area of origin analysis indicate the location of the backtracked bloodstain trajectory to be at the geometric centre or at the tip of the bloodstain ellipse. However, it is unknown how the first point of contact and the blood drop trajectory (here defined as the locus of the centre of mass of the drop as it travels) are related empirically. Thus, this study aims to look at how the initial point of contact and the trajectory at the impact of a blood drop relates to the formed bloodstain ellipse. Two volumes of blood (0.013 ml and 0.071 ml) were dropped from a height of 10 cm and 40 cm onto an inclined surface at 0°, 15°, 30°, 45°, 60°, and 75°. The transition from a spherical blood drop to an elliptically shaped bloodstain was recorded using a high-speed camera for all tests. A total of 72 ellipses were analyzed to determine the location of the first point of contact and trajectory point of the blood drop and how they relate to the formed elliptical bloodstain. A relationship was found between the first point of contact and the bloodstain trajectory which was dependent on the impact angle. However, there were clear deviations from theoretical assumptions due to blood drop oscillations, the effects of gravity, and the natural fluid characteristics of blood. The results of this study may assist bloodstain pattern analysts and software developers by more accurately applying the location of the blood drop trajectory based on empirical data. • The first point of contact follows a similar trend to the sine value. • The trajectory point moves along the half-length of the bloodstain. • The trajectory point and first point of contact are mainly at different locations. • The trajectory point is not always at the centre or tip of the ellipse. • The first point of contact is not always at the centre of tip of the ellipse. [ABSTRACT FROM AUTHOR]

Electrode Induction melting Gas Atomization (EIGA) is a free-fall gas atomization process used to produce metal powders, where a swirling supersonic gas jet hits a molten metal stream atomizing it into droplets through various fragmentation mechanisms. Fragmentation mechanisms of molten Ti64 are investigated by high-speed video visualization. The role of gas pressure and melting chamber overpressure on the fragmentation mechanisms and on the particle size distribution is determined. The mechanisms observed are fiber breakup, bag breakup and Rayleigh breakup for primary fragmentation and bag breakup and shear breakup for secondary fragmentation. Increasing the gas pressure promotes shear breakup and creates finer droplets. A model based on log-stable law is proposed to fit the mass distribution according to the dominant fragmentation regime. A good agreement is observed between the different analysis (dominant atomization regime, mass cumulative distribution evolution, parameters of log-stable law). A criterion for prediction of nozzle clogging is devised. [Display omitted] • High-speed visualization of liquid metal breakup mechanisms in an EIGA atomizer. • The effect of atomisation pressure and melting chamber pressure is analysed. • A log-stable law model is presented to describe the measured mass distribution. • A too low overpressure in the melting chamber favors nozzle clogging. [ABSTRACT FROM AUTHOR]

• Application of automotive squibs with ZPP mixture in a 20L sphere for dust explosion measurements. • Evaluation of ignitor burning time on combustion behavior of lycopodium by application of optical and pressure sensors. • Application of high-speed imaging techniques for measurement of fireball dimensions. • Comparison of automotive squibs and regular Sobbe ignitors of several different energies on the dust explosions. The type of ignition plays a crucial role in dust explosion measurements. To date, research on the ignition part has mostly focused on ignition by electric spark, or pyrotechnic ignitor, with various energies. Only a few works focus on the use of different types of pyrotechnic ignitors and different pyrotechnic mixtures. This work examines the effect of the pyrotechnic ignitor's energy, design, and pyrotechnic composition on the measurement of safety parameters of combustible dusts. Measurements were carried out with lycopodium in a 20 dm3 explosion chamber, recording the pressure and output voltage from the optical probe. A high-speed imaging technique were used to investigate ignitors behaviour. In summary, the ignitor type and its energy have significant effect on measured explosion parameters. It was shown that burning of the pyrotechnic mixture in the Standard Sobbe ignitors overlaps ignition and burning of Lycopodium dust itself. Squibs burn for a shorter time while producing a significant pressure wave which acting on the dust cloud, causing its disturbances and influencing explosion parameters. [ABSTRACT FROM AUTHOR]

Stereocorrelation (SC) is a versatile experimental method increasingly used to measure 3D surface displacements in complex mechanical tests. However, convergence issues may arise when gray-level conservation is no longer validated, particularly when local specular reflections are observed. Brightness and contrast corrections (BCCs) are added to the Global Stereocorrelation framework, including different spatial regularization strategies. A challenging experimental test case was chosen for validation purposes where extreme brightness and contrast changes were observed. An impact test on laminated glass was monitored with two high-speed cameras. It is shown that BCCs significantly improve the robustness and convergence rate for both calibration and kinematic measurements. Moreover, the numerical implementation cost into a finite element stereocorrelation code is negligible. • Camera calibration and kinematic measurements formulated for global stereocorrelation • Brightness and contrast corrections (BCCs) are decomposed over a finite element mesh • Staggered calibration/kinematic measurements and BCCs are easily implemented • Procedure tested on a difficult test case where specular reflection occurs • BCCs induce better and faster convergence to the solution [ABSTRACT FROM AUTHOR]

[Display omitted] This study introduced a high-speed precision dual-chamber maize seed metering device and examined the impact of irregular-shaped holes on the planting quality in order to enhance the precision of maize planting. Based on the characteristic dimensions of maize seeds, the horizontal-profiled seed metering plates, lateral-profiled seed metering plates, vertical-profiled seed metering plates, and round-hole seed metering plates were developed. This research examined how the performance of individual seed metering plate types is affected by varying forward velocity and negative pressure conditions. Utilizing high-speed camera technology, statistical analysis was conducted on the adsorption posture data of maize seeds with different hole shapes. It was found that the qualified index showed a positive correlation with the quantity of seeds in the horizontal posture, while the quantity of seeds in the lateral posture and vertical postures collectively influenced the multiples index and the miss index. This research explored the optimal operating parameters for the high-speed precision dual-chamber maize seed metering device, with a forward velocity of 15 km/h and a negative pressure of 14 kPa. The validation tests yielded the qualified index of 98.13 %, the multiples index of 1.19 %, and the miss index of 0.68 %. This study offers insight for developing different seed metering devices based on seed characteristic dimensions, while also offers insights into the mechanism for improving the seeding quality of high-speed precision seed metering devices. [ABSTRACT FROM AUTHOR]