Search Results (1,224)

Objective: This study aimed to experimentally investigate the biomechanical and performance differences between the grab start (GS) and the kick start (KS) with each leg on the kickplate (KSR, KSL) in Bi-Finswimming (BFS). It focused on the effect of foot placement on the starting block, equipped with an adjustable, inclined rear kickplate (Omega, OSB11), to determine potential performance advantages and contribute evidence-based recommendations for optimizing start techniques in competitive BFS. Methods: Thirteen national-level finswimmers (seven males, six females; age: 17.7 ± 2.1 years) voluntarily participated. Each athlete performed two trials of three start techniques (GS, KSR, KSL) over three days in a randomized order. Four synchronized cameras recorded video data. Performance metrics (time to 5 m (T5), 15 m (T15), 25 m (T25), reaction time, block time (BT), flight time (FT), and entry characteristics) along with joint angles (hip, knee, ankle), were analyzed using Kinovea software (v. 2024.1). A two-way repeated measures ANOVA (start type × gender) was conducted to analyze performance metrics, and a paired-sample t-test assessed differences in joint angles. Also, correlations between dependent (type of start) and independent variables (start-examined variables) were examined through bivariate Pearson’s r analysis. Results: No significant gender differences were found (p > 0.05). Significant differences emerged between the starting techniques, with KS showing faster T5, T15, and T25 (p < 0.001, η²_p = 0.6; p < 0.001, η²_p = 0.5; p < 0.05, η²_p = 0.3, respectively). BT was significantly longer in GS compared to KS (p < 0.001, η²_p = 0.8), while FT was shorter in GS (p = 0.002, η²_p = 0.4). Faster T5, T15, and T25 were associated with increased flight distance and longer FT in KSL. Conclusions: The kick start generally outperforms the grab start, especially in block time, in Bi-Finswimming. These preliminary results suggest that it could be considered for future discussion regarding potential legalization by the World Underwater Federation, pending further research. Full article

High-precision time synchronization among nodes of the airborne-based pseudolite navigation augmentation positioning system (A-PNAS) is a crucial indicator for ensuring the accuracy of positioning services. Due to the flight characteristics and external factors’ influence, the airborne platform usually undergoes random motion. Therefore, the time-varying effect errors and Doppler effect errors will be introduced into the clock skew measurement results during the time-synchronous processing. In A-PNAS with meter-level positioning accuracy, the time synchronization accuracy (TSA) between nodes usually needs to be within 2 ns. These dynamic errors will have an impact on the TSA between nodes, which cannot be ignored. Based on the analysis of the principle of dynamic error generation and the available sensors, a multi-sensor combination method for correcting dynamic errors is proposed. This method calculates and corrects the dynamic errors based on the motion measurements from sensors. The simulation test results show that the degree of improvement in correcting dynamic errors by this method is basically close to 80%. It can effectively meet the requirements of high-precision time synchronization system and can provide an effective reference for the high-precision time synchronization processing of similar space-based platform collaborative systems. Full article

The CERN n_TOF facility is a research infrastructure specifically designed for studying neutron-induced nuclear reactions. Pulsed white neutron beams are delivered toward three experimental areas, two of them at different baselines to apply the time-of-flight technique, and another one very close to the neutron source for activation studies. High intensity and high neutron energy resolution make n_TOF a unique facility. A major component of the physics program at n_TOF is dedicated to the measurement of key neutron induced reactions for nuclear astrophysics, relevant to nucleosynthesis in stars, the Big Bang primordial nucleosynthesis as well as Cosmochronology. A review of the relevant results obtained at the n_TOF facility is reported, together with details of challenging new measurements in preparation. Full article

Real-time kinematic (RTK) unmanned aerial vehicles (UAVs) have become more popular in recent years, mostly because they can reduce the number of ground control points (GCPs) that have to be measured in the field and are required for aerial triangulation. Additionally, thanks to RTK technology, every image has its exterior orientation parameters measured with centimeter accuracy; thus, the block is more stable and there is a lower risk of some geometric distortions appearing within the block, especially in its central part. In this article, the influence of RTK observations on image orientation is analyzed based on a planned UAV test field in Józefosław, near Warsaw, Poland. As part of the experiment, UAV flights with DJI Phantom 4 RTK and DJI Phantom 4 Pro V2.0 were conducted, and 38 GCPs were located in the area. The results show that RTK observations from UAVs can significantly improve the accuracy of aerial triangulation, as inclusion of oblique images also does. For Phantom 4 RTK images, a single GCP was generally sufficient to achieve satisfactory accuracy, whereas six GCPs were required for the Phantom 4 Pro V2.0. Full article

This article presents a proprietary method for measuring and adjusting the position of DC generator brushes relative to the neutral zone. This method enables shaping the characteristics of the power sources of the aircraft’s DC power grids, which has a beneficial effect on counteracting the aging process. Using generators with varying operating times (flight hours), selected research results on the effect of the brush position angle α relative to the magnetically neutral zone on operating conditions are presented. In addition, examples of abnormal operation of the DC electrical network in transient states and their possible negative effects on the operation of the aircraft (A/C) power network are presented. Finally, research results are presented demonstrating the practical application of power source characteristic shaping to effectively counteract the aging process of aircraft DC power networks. Full article

In this study, the cosmeceutical potential of a 70% ethanol extract of Rosa lucieae was investigated as a multifunctional bioactive ingredient. The extract was systematically evaluated for its antioxidant, anti-melanogenic, and anti-aging properties, and was comprehensively phytochemically profiled using ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry. The analysis tentatively identified 21 metabolites, including phenolic acids (gallic acid, ellagic acid, and corilagin), flavonoids (catechin, rutin, quercetin, hyperoside, and quercitrin), and glycosidic derivatives (e.g., phlorizin), several of which are well-documented for their skin-protective effects. Quantitative measurements confirmed high polyphenol and flavonoid contents, correlating with strong radical-scavenging and reducing capacities in α-diphenyl-β-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, as well as ferric ion reducing antioxidant power assays. Moreover, the extract inhibited tyrosinase activity and 3,4-dihydroxyphenylalanine oxidation, thereby suppressing melanin biosynthesis. In addition, marked inhibitory effects against collagenase, elastase, and hyaluronidase were observed; these enzymes are critically involved in extracellular matrix degradation and skin aging. Taken together, these results indicate that the biological activities of R. lucieae are supported by a diverse polyphenol- and flavonoid-rich chemical profile, highlighting the potential of this plant as a natural multifunctional ingredient for cosmeceutical, nutraceutical, functional food, and preventive healthcare applications. Full article

Deoxynivalenol (DON) is one of the most common trichothecene mycotoxins found in cereals, posing a significant hazard to food and feed safety. Insects, especially the yellow mealworm (Tenebrio molitor), offer promising alternative protein sources; however, their capacity to metabolise mycotoxins and the nutritional implications are still not fully understood. In this study, T. molitor larvae were reared for two weeks on diets containing DON at 663 or 913 µg/kg, and their biomass was analysed using Liquid Chromatography–Quadrupole Time-of-Flight Mass Spectrometry (LC-QTOF) for DON metabolites and free amino acids, as well as Gas Chromatography–Flame Ionization Detector (GC-FID) for fatty acid profiles. Larvae metabolised DON via multiple pathways, including sulfonation, glucuronidation, sulfation, glucosylation, and de-epoxidation, with a time- and dose-dependent shift towards glucosylation and de-epoxidation. DON exposure significantly reduced the levels of essential amino acids such as methionine, lysine, phenylalanine, and isoleucine, and lowered metabolic intermediates like aspartic and glutamic acid. Conversely, prolonged DON exposure increased linoleic acid levels in larval fat, indicating altered lipid metabolism. These findings demonstrate that T. molitor larvae detoxify DON but incur measurable metabolic costs, leading to changes in amino acid and fatty acid profiles. The dual effect—reduction of toxin levels and nutritional shifts—highlights both the potential and the challenges of using insects for sustainable feed production. Full article

The severity of natural disasters is increasing every year, having an impact on many people’s lives. During the response phase of disasters, airports are important hubs where relief aid arrives while people need to be evacuated to safety. However, the airport often forms a bottleneck in these relief operations because of the sudden need for increased capacity. Limited research is carried out on the operational side of airport disaster management. Experts identify the main problems as first the asymmetry of information between the airport and the incoming flights, and second the lack of resources. The goal of this research is to gain understanding of the effects of incomplete knowledge of incoming flights with different resource allocation strategies on the performance of the cargo handling operations in an airport after a natural disaster event. An agent-based model is created, where realistic offloading strategies with different degrees of information uncertainty are implemented. Model calibration and verification are performed with experts in the field. The model performance is measured by the average turnaround time, which can be split into offloading time, boarding time and the cumulative waiting times. The results show that the effects of one unplanned aircraft are negligible. However, the waiting times and other inefficiencies rapidly increase with the more unplanned aircraft arriving. Full article

To achieve rapid screening and semi-quantitative analysis of pesticide residues in mobile laboratories and on-site tea testing, a novel method based on thermal-assisted plasma ionization–time-of-flight mass spectrometry (TAPI-TOF/MS) has been developed for the detection of 20 pesticide residues, including insecticides and fungicides, in tea. This method eliminates the need for liquid chromatography, or column connections. Instead, it utilizes the high temperature of the sample inlet and stage to fully volatilize and inject the sample. By integrating TAPI-TOF/MS with an automated pesticide residue pretreatment instrument, the entire sample extraction process can be performed automatically. The analysis time for each sample has been reduced to 1.5 min, allowing for the processing of 60 samples per batch. An accurate mass spectrometry database has been established for screening and confirmation purposes. The software automatically matches the mass spectrometry database by analyzing the measured ion mass deviation, ion abundance ratio, and the relative contribution weight of each ion, generating a qualitative score ranging from 0 to 100. The lowest concentration yielding a qualitative score of ≥75 was defined as the screening limit, which ranged from 0.10 to 5.00 mg/kg for the 20 pesticides. Within their respective linear ranges, the method demonstrated good linearity with correlation coefficients (R²) ranging from 0.983 to 0.999. The average recovery rates (n = 5) of the target pesticides ranged from 70.6% to 117.0% at the set standard concentrations, with relative standard deviations (RSD) ranging from 1.7% to 13.1%. Using this method, 15 tea samples purchased from the Rizhao market in China were analyzed. Ten samples were found to contain residues of metalaxyl or pyraclostrobin, yielding a detection rate of 66.7%. This technology provides technical support for the rapid detection and quality control of multiple pesticide residues in tea, meeting the requirements for high-throughput and on-site analysis. Full article

Pipelines are extensively used in offshore equipment. Accurate and non-destructive measurement of hoop stress conditions within pipes is critical for ensuring the integrity of offshore structures. However, the existing technology to measure the hoop stress of the pipeline needs to planarize the surface of the pipeline, which greatly limits the detection efficiency. This study proposes a method for pipeline hoop stress measurement using a planar longitudinal critically refracted (LCR) probe, based on correcting LCR wave-propagation paths, which solves the problem of pipeline planarization in pipeline hoop stress measurement. First, a linear relationship between stress variations and ultrasonic time-of-flight changes in the material was established based on the acoustoelastic effect. Finite element analysis was then used to construct an acoustic simulation model for the hoop direction of the pipeline. Simulation results showed that LCR waves propagated within a wedge as quasi-plane waves and, upon oblique incidence into the pipeline, traveled along the chordal direction. Furthermore, using ray tracing methods, a mapping relationship between the pipeline geometry and the ultrasonic propagation path was established. Based on this, the LCR pipeline hoop stress measurement (LCR-HS) method was proposed. Finally, a C-shaped ring was employed to verify the measurement accuracy of the LCR-HS method. Experimental results indicated that the measurement error decreased with increasing pipe diameter and fell below 8% when the diameter exceeded 400 mm. This method enables precise measurement of hoop stress on curved surfaces by revealing the hoop propagation behavior of LCR waves in pipelines. The findings provide a technical reference for evaluating pipeline stress states, which is of significant importance for assessment of pipeline integrity. Full article

Animal temperament, defined as consistent behavioral and physiological responses to stressors, plays a crucial role in cattle welfare, productivity, and safety during handling. This motivates researchers to identify objective, non-invasive methods for temperament assessment. Infrared thermography (IRT) has emerged as a promising tool to detect superficial temperature changes associated with stress and temperament in cattle. This study aimed to evaluate how superficial temperature variations measured by IRT in fattening bulls are influenced by environmental temperature, humidity, and temperament. The study involved 223 bulls at approximately 7.5 months old, while thermal images of eye and muzzle regions were captured at baseline and during restraint in a squeeze chute. Temperament was assessed using chute score and flight time, and environmental conditions were recorded via a temperature–humidity index (THI). Results showed significant increases in eye and muzzle temperatures during handling. Notably, changes in eye temperature were independent of environmental THI but correlated with flight time, with more temperamental bulls displaying larger temperature increases. In contrast, changes in muzzle temperature were strongly influenced by ambient THI and its variation at handling, consistent with the region’s thermoregulatory function. Temperament explained a small proportion of temperature variation. A follow-up experiment on a subset of 104 bulls around 11 months old showed no significant age effects on the IRT–temperament relationship. These findings indicate that IRT, particularly of the eye region, holds promise as a non-invasive, objective method to assess stress responses related to temperament in cattle. Careful selection of thermal regions and accounting for environmental influences are critical. While IRT alone accounts for limited variability, its integration with other behavioral and physiological measures could enhance temperament evaluation. This approach offers novel opportunities for improving animal welfare and management by identifying highly temperamental individuals without invasive procedures. Future research with higher temporal resolution and varied stressors is warranted to further elucidate temperature dynamics associated with temperament. Full article

Assessing the fall risk of a patient in a busy clinical setting is challenging. Tests such as the timed-up-and-go test and narrow beam walking are difficult to perform due to space restrictions. Moreover, it is not easy to directly connect the results of these tests to fundamental biomechanical principles of gait stability, which emphasize the interplay between the movements of the body’s center of mass (CoM) and its base of support (BoS). Herein, we show how a 1.2 m-long treadmill and a single “time-of-flight” Azure Kinect camera can capture the CoM-BoS interplay within 5 min. The CoM was calculated by dividing the body into 14 segments determined from 20 joint positions measured by the Kinect camera’s body tracking SDK. By tracking the CoM and joint positions from stride to stride, we can evaluate different gait stability metrics using a markerless, contactless, space-efficient approach. A large digital database of CoM movements relative to foot placement will be useful for the future development of statistical and machine learning techniques for identifying subjects at higher risk of falling. Full article

The load/strain time–history experienced by aircraft structures during service is crucial original input data for structural life reliability design, life extension, and health monitoring management. Accurately and reliably measuring the strain time–history of aircraft structures and their corresponding loading states is key. Aiming to improve upon the shortcomings of traditional airborne strain measurement methods, this paper proposes a key strain airborne measurement method suitable for load-bearing structures based on the characteristics and requirements of a certain type of aircraft load-bearing structure. An airborne multi-channel synchronous sampling test and acquisition system is designed and integrated for airborne measurement and acquisition of key strains and corresponding loading states of load-bearing structures. The main factors affecting the output of aircraft structure strain airborne measurements are summarized. Based on this, an uncertainty evaluation model for the airborne strain testing system is established, and the uncertainty of the output strain is quantitatively given using multivariate fuzzy evaluation. The key strain time–history of the load-bearing structure is obtained through flight measurement data collection and processing, and the collected strain history is analyzed in combination with simultaneously collected flight parameters. The results show that the proposed airborne strain measurement method and the integrated airborne strain measurement and acquisition system can reliably measure and reproduce the real loading history of the structure, providing reliable data support for structural damage estimation and life prediction management. It also provides an effective and practical reference for strain measurement of other aircraft structures. Full article

A layerwise laminate FE model capable of predicting the dynamic response of delaminated composite beams with piezoelectric actuators and sensors encompassing local non-linear contact and sliding at the delamination interfaces was formulated. The kinematic assumptions of the layerwise model enabled the representation of opening and sliding of delamination interfaces as generalized strains, thereby allowing the introduction of interfacial contact and sliding effects through constitutive relations at the interface. This realistic FE model, assisted by representative experiments, was used to study the time response of delaminated active sensory composite beams with predefined delamination extents. The time response was measured and simulated for narrowband actuation signals at two distinct frequency levels using a surface-bonded piezoceramic actuator, while signal acquisition was performed with a piezopolymer sensor. Four different composite specimens, each containing a different delamination size, were used for this study. Experimental results were directly compared with model predictions to evaluate the performance of the proposed analytical approach. Damage signatures were identified in both the signal amplitude and the time of flight, and the sensitivity to delamination size was examined. Finally, the distributions of axial and interlaminar stresses at various time snapshots of the transient analysis are presented, along with contour plots across the structure’s thickness, which illustrate the delamination location and wave propagation patterns. Full article

Objectives: This study analysed the recovery process after an official soccer match by monitoring changes in markers of muscle damage and oxidative stress, and endocrine, neuromuscular, and perceptual responses. Methods: This repeated-measures observational study included thirteen male amateur soccer players. Blood biomarkers, neuromuscular performance in countermovement jump, and perceived wellness were measured at four time-points: the morning of the match-day, immediately post-, and 24 h and 48 h post-match. Results: Except for CK, which remained elevated at 48 h post-match, lactate dehydrogenase, C-reactive protein, uric acid, testosterone, cortisol, and testosterone to cortisol ratio returned to baseline between 24 h and 48 h post-match (p < 0.05). Jump height was significantly decreased at 24 h and 48 h post-match, while peak rate of force development and other countermovement jump time-based metrics (i.e., time to take off, time to peak force, reactive strength index modified, flight time to contraction time ratio) were impaired immediately after the match and recovered earlier (p < 0.05). Peak values for perceived fatigue and delayed onset muscle soreness were observed immediately post- and at 24 h post-match, respectively (p < 0.05). Conclusions: While certain physiological, neuromuscular, and perceptual changes may return to baseline levels within 24 h or 48 h post-match, amateur soccer players still manifest exercise-induced muscle damage symptoms and can be considered fatigued after a 48 h recovery period. Full article