Acceleration Test Research Articles

Rotor Position Estimation Algorithm for Surface-Mounted Permanent Magnet Synchronous Motor Based on Improved Super-Twisting Sliding Mode Observer

In response to the chattering issue inherent in sliding mode observers during rotor position estimation and to enhance the stability and robustness of sensorless control systems for surface-mounted permanent magnet synchronous motors (SPMSM), this study proposes a rotor position estimation algorithm for SPMSM based on an improved super-twisting sliding mode observer (ISTSMO) and a second-order generalized integrator (SOGI) structure. Firstly, the super-twisting algorithm is introduced to design the observer, which effectively attenuates the sliding mode chattering by using continuous control signals. Secondly, SOGI is introduced in the filtering stage, which not only effectively addresses the time delay issues caused by traditional low-pass filters but also enables the observer to extract rotor position information by monitoring only the back electromotive force (back-EMF) signal of the α-phase, thereby simplifying the observer structure. Finally, the proposed scheme is experimentally compared with the traditional sliding mode observer on the YXMBD-TE1000 platform. The experimental results showed that during motor acceleration and deceleration tests, the average speed estimation error was reduced from 141 r/min to 40 r/min, and the maximum position estimation error was reduced from 0.74 rad to 0.29 rad. In load disturbance experiments, the speed variation decreased from 781 r/min to 451 r/min, and the steady-state speed fluctuation was significantly reduced. These results confirm that the proposed observer exhibits superior stability and robustness.

Quantifying the Impact of Sustained Acceleration on Critical Care Transport Medical Equipment

ABSTRACT Introduction Military and commercial stakeholders are investing to explore the use of hypersonic aircraft and orbital spacecraft to transport cargo, medical supplies, passengers, and casualties. These vehicle platforms require periods of sustained acceleration, but to date, these dynamic forces have not been comprehensively considered in the environment of critical care patient movement because injured patients and advanced aeromedical evacuation (AE) equipment are rarely subjected to these conditions. While military AE equipment does undergo crash hazard acceleration testing, equipment functionality during or after sustained acceleration remains to be evaluated. This study was performed to fill that knowledge gap. Materials and Methods AE equipment currently used by the U.S. Air Force and Critical Care Air Transport Teams (ZOLL EMV+ 731 ventilator and ZOLL Propaq MD cardiac monitor) was subjected to low (2.5 g), moderate (4.5 g), and variable acceleration (1.5–4.5 g) for 3-minute periods at the KBR Brooks Centrifuge. AE equipment was tested for functionality in 3 different orientations (gX, gY, and gZ). Predetermined variations were made in equipment input settings to ensure each equipment item would function across mission-relevant conditions (differing ventilator tidal volumes, differing cardiac monitor arterial pressure inputs, etc.). AE was evaluated for accuracy compared to controlled inputs, alarm conditions, and equipment failure. Results The EMV+ 731 ventilator and Propaq MD cardiac monitor had no equipment failures during testing. The ventilator had clinically negligible variations in tidal volume, peak pressure, and fraction of inspired oxygen during acceleration. At the highest tidal volume tested (480 mL), the ventilator had elevated peak pressure results. However, we believe this was due to limitations in test-lung resistance and was not related to a ventilator fault. Mild effects of sensor orientation were recorded in the Propaq MD blood pressure results; for example, gX and gY differed by 5.9 ± 1.21 mmHg at 75 mmHg input (P < .01) and 6.45 ± 1.229 mmHg with 150 mmHg input (P < .001). Conclusions The EMV+ 731 ventilator and Propaq MD cardiac monitor had reliable clinical performance despite sustained acceleration. This knowledge will facilitate immediate follow-on experimentation with advanced models of combat injury during simulated medical evacuation in sustained acceleration environments.

Wound healing potential of mouth gel containing isopimarane diterpene from Kaempferia galanga rhizomes for treatment of oral stomatitis.

Oral ulcers have an impact on 25% of the global population including patients who are suffering from chemotherapy and radiotherapy treatments. Kaempferia galanga L. has been traditionally used for treatment of mouth sores and tongue blisters. However, the wound healing study of isopimarane diterpenes isolated from K. galanga is still limited. This study aims to evaluate the wound healing potential of 6β-acetoxysandaracopimaradiene-1α,9α-diol (KG6), a compound isolated from Kaempferia galanga, by examining its biological activities. Additionally, we investigate the physicochemical and biological properties of (KG6) in formulated mouth gels. The KG6 mouth gels at 0.10%, 0.25% and 0.50% w/w were formulated using sodium carboxymethylcellulose as a gelling agent, and their physicochemical and biological stabilities were assessed through a heating-cooling acceleration test. The quantification of KG6 contents in KG6 mouth gels was determined using gas chromatography. Both KG6 and KG6 mouth gels were evaluated for their wound healing properties including cell proliferation, cell migration, and antioxidant activity (H2O2-induced oxidative stress) in human gingival fibroblast (HGF-1-ATCC CRL-2014) (HGF-1). In addition, the anti-inflammatory activity against nitric oxide (NO) production was investigated in macrophage cells (RAW 264.7). After KG6 mouth gels were incubated under heating-cooling acceleration condition, the physicochemical properties of the KG6 mouth gels remain stable across various parameters, including appearance, color, smell, texture, pH, viscosity, separation, and KG6 content. The biological studies indicated that the KG6 compound possessed good wound healing potential. The 0.50% KG6 mouth gel exhibited marked anti-inflammatory effect by inhibiting NO production with an IC50 of 557.7 µg/ml, comparable to that of Khaolaor mouth gel, a positive control. The 0.25% KG6 mouth gel increased HGF-1 cell proliferation to 101.7-103.5%, whereas all formulations of KG6 mouth gel enhanced HGF-1 cell migration to 94.7-98.9%, higher than Khaolaor mouth gel (73.5%). Moreover, 0.50% KG6 mouth gel also showed a good antioxidant effect under H2O2-induced oxidative stress. This study substantiates the significant biological activities related to the wound healing property of 0.50% KG6 mouth gel for treatment of aphthous ulcers and oral stomatitis from chemotherapy and radiotherapy treatments.

Dynamic Response Analysis of Overpass Ramp Based on Grey System Theory Model

An interchange is a pivotal traffic facility that connects highways and controls access. It is necessary to study their dynamic response characteristics to analyze the operational safety of ramp bridges on interchanges. Based on the numerical simulation results of the finite element model of the Fuxing Interchange Bridge, non-destructive measurement techniques were used to conduct field dynamic load tests on the bridge, including ramp strain testing and acceleration testing. These tests aimed to study the dynamic response characteristics of the ramp bridge under moving loads. Due to the design speed limitation of the ramp bridge, the grey prediction GM(1, 1) model was used to predict the maximum dynamic deflection, maximum dynamic strain, and vibration acceleration when the vehicle speed was 60 km/h. Subsequently, finite element software was used to simulate the dynamic deflection under vehicle speeds ranging from 30 to 60 km/h. The simulated value was compared with the predicted value, and the difference between the simulated value and the predicted value was slight. This model can evaluate the operational safety performance of off-ramps at different speeds.

Comparison of Thermal Conductivity and Long-Term Change of Building Insulation Materials According to Accelerated Laboratory Test Methods of ISO 11561 and EN 13166 Standard

The insulation performance of a building is one of the most fundamental factors in reducing its energy use. The insulation of the building envelope is the main factor that directly affects the cooling and heating loads, which is responsible for the largest portion of the building’s energy consumption. Recently, in South Korea, building insulation materials such as PIR and PF, which have not only fire resistance but also high insulation performance, are becoming mainstream in the industry as fire safety standards have been strengthened. However, there are concerns about the long-term change of high-performance insulation materials. In particular, in contrast with existing plastic insulation materials such as EPS and XPS, the evaluation of the reliability of the long-term change of insulation materials with a high closed-cell rate is becoming an issue. This is because, unlike the existing EPS and XPS, there are insufficient international standard test methods for evaluating the long-term thermal performance of composite insulation materials such as polyurethane and phenol. They are combined with layers of other types of thermal insulation and/or one or both of the surfaces are covered with coatings, facings, membranes or other surface skins, all serving some functional purpose depending on the product application. In this study, the long-term change of building insulation materials was tested and analyzed based on the standard of the accelerated aging test. Four types of building insulation materials were used in the experiment: EPS, XPS, PF and PIR. The accelerated aging tests were conducted based on ISO 11561 and BS EN 13166 standards (accelerated laboratory test methods). The results of the accelerated aging tests for the materials were analyzed and the thermal resistance of the insulation materials was also compared. From the test results according to the slicing test method specified in the ISO 11561, the thermal resistance of EPS, XPS, PF, and PIR with long-term changes decreased by 2.4%, 8.5%, 16.4%, and 18.0%, respectively, compared to the initial thermal resistance. From the test results according to the 70 °C heat acceleration test method specified in the EN 13166, the thermal resistance decreased by 2.0% for EPS, 6.7% for XPS, 8.7% for PF and 13.6% for PIR, compared to their respective initial thermal resistance values. The EPS showed highly similar thermal resistance changes for the two different test methods. It was found that there was no effect from the slicing of the insulation material, and the accelerated aging test showed minimal changes in thermal resistance. In contrast, the other insulation materials exhibited different thermal resistance changes depending on the test method, with each material showing a thermal resistance change of 8.8% to 15.9% when subjected to the accelerated aging test.

Forecast Li Plating in LiFePO4/Graphite Cells: Proposal and Issues

Lithium-ion battery (LIB) for stationary use is required non-destructive degradation and SOH estimation in operation with sufficient safety and long-term use. We have developed non-destructive and post-mortem analysis for large format batteries. In case of non-destructive analysis, differential voltage analysis (dV/dQ) have been applied for the detection of lithium (Li) plating in operation. In addition, we have introduced Ar-filled glove box specially designed for large format battery disassembly to confirm the capacity fade of cathode / anode materials including Li plating on the anode. We selected 20 conditions as acceleration tests using cylindrical 26650 type LiFePO4/Graphite (LFP/Gr) cells with nominal capacity of 3.4 Ah. We applied the following four non-destructive approaches to the cells with under 90% SOH to forecast Li plating; i) slope of open circuit voltage (OCV) during galvanostatic interruption of titration technique (GITT), ii) gap of charge end voltage and OCV, iii) Gr capacity estimation using dV/dQ peak to peak (Gr 4th and/or 3rd to 2nd stage) capacity or Gr 2nd stage dV/dQ peak position, and iv) peak height and/or width of dV/dQ at Gr 2nd stage. In case of OCV monitoring, we focused on OCV trend at Gr 2nd and 1st stage coexisting region (0.5< x <1 in Li x C6). In the normal reaction, OCV at the region is almost flat due to the two-phase reaction of Gr and also LFP. However, we found the cell with OCV slope at the corresponding region was an indicator to forecast Li plating.In addition, the gap of charge end voltage and OCV during GITT was also an indicator to forecast Li plating. In such case, we could forecast Li plating by using two charge end voltage and subsequent OCV values at D10% SOC at the region of 0.5< x <1 in Li x C On the other hand, Li plating forecast using dV/dQ peak positions (used as an indicator of Gr capacity) could be applied in some cycle conditions but could not be applied other conditions including inhomogeneous capacity fade in operation.Then we focused on peak height and width of dV/dQ at Gr 2nd stage and found that the trend of its peak shape will be an indicator to forecast Li plating. Furthermore, such forecast can grasp at limited SOC range operation including Gr 2nd stage region. Therefore, it will be a possibility to forecast Li plating in a short time using single dV/dQ profile. We will report merits and issues of the procedure to forecast Li plating including the evidence of Li plating by post mortem analysis.

Elucidation of Degradation Mechanism of Lithium-Ion Batteries Under High Temperature Environment

Introduction With the recent increase in energy demand, lithium-ion batteries (LIBs), which have high lifetime characteristics and energy density, are being considered for batteries used to stabilize power supply and to store renewable energy. However, the detailed degradation mechanism over a wide range has not yet been clarified. Previous studies have reported that float charging, which assumes the use of LIBs as backup power sources, and the combination of float charging and occasional discharge at room temperature conditions cause significant degradation.1 On the other hand, as suggested by the fact that battery acceleration tests are generally conducted at high temperatures, it is important to understand the degradation conditions at high temperatures. In fact, heat is generated by charging and discharging when large storage batteries are used. Considering the above, the purpose of this study is to clarify the temperature dependence in degradation by conducting degradation tests combining float charge and occasional discharge at 25°C and 40°C in comparison. Experimental Commercially available 18650 cylindrical LIBs (Panasonic, NCR18650R, nominal capacity: 3350 mAh), presumably from the same lot, were used for the degradation test. The uniform performance was validated with some cycling tests. Degradation tests comprise three key parameters: (1) charging and discharging patterns, (2) operating voltage range, and (3) operating temperature. The detailed conditions are shown in Table 1. A total of 12 patterns of degradation tests are conducted under combinations of these conditions. Analysis of the degradation status is regularly performed by differential voltage analysis of discharge curves, electrochemical impedance measurement, and operando neutron diffraction measurement as non-disassembly analysis.Operando neutron diffraction measurements were used to measure changes in the crystal structure of the positive electrode. Diffraction measurements were performed at room temperature using a time-of-flight powder diffractometer at the Materials and Life Science Experimental Facility of the Japan Proton Accelerator Research Complex2. The test cell was first charged at 0.5C (1675 mAh) with a cutoff potential of 4.2 V, followed by constant-voltage charging at a cutoff current of 0.02C (67 mAh), to achieve a fully charged state, and then the diffraction profile in the open circuit state was measured after 1 h rest. Next, diffraction measurements were performed while discharging at a constant current of 0.1 C (335 mAh) up to 2.5 V. One diffraction profile was obtained from the integrated data of signals obtained during 10 minutes. Finally, the diffraction measurement was completed with full discharge. The Rietvelt analysis was performed using the diffraction profiles obtained in these measurements to refine crystal parameters such as lattice constants and mass ratios, which indicate the existence ratio of each constituent material. Results and discussion After 100 days or 100 cycles, the most degraded condition is the mode that combines float charging and once-a-day discharge, operating in a high SOC region and at high temperatures. The differential voltage analysis of discharge curves showed that the loss of lithium inventory (LLI) was rarely observed for the mere float charge whereas LLI was clearly found when the combination of float charging and occasional discharge was employed. It was also confirmed that LLI occurred more when the degradation was operated under high temperature conditions. On the other hand, electrochemical impedance measurements showed that the internal resistance of the positive electrode was significantly increased than that of the negative electrode, suggesting the resistance increase in the positive electrode (RIPE) was caused by the species formed at the negative electrodes re-oxidized at the positive electrode.The operando neutron diffraction profiles of the fresh cells were measured and determined to be layered positive electrode material for the positive electrode and graphite for the negative electrode. The 003 diffraction profiles of the layered positive electrode material in the fresh cell or degraded cell are shown in Fig. 1. Comparing the fresh cell and degraded cell, a broadening of the profile is observed in the early stage of discharging in the latter, which suggests the RIPE causing the charge-discharge reaction distribution. These results indicate that the combination of float charging and discharging under high temperature conditions not only causes LLI, but also significantly causes the RIPE mode, resulting in capacity degradation.

Research on digital twin-assisted dual-channel parallel convolutional neural network-transformer rolling bearing fault diagnosis method

The existing data-driven fault diagnosis methods face some significant problems in practical applications. Many traditional methods rely on a large number of high-quality labeled data for training, but in the industrial environment, the actual fault data obtained is often limited and unbalanced. This data scarcity seriously limits the diagnostic ability of the model and is prone to insufficient diagnostic accuracy. In addition, the data-driven method has a strong dependence on data, and it is prone to misjudgment in the face of complex environments such as noise interference and equipment state changes. These problems jointly restrict the application effect of fault diagnosis methods in industrial actual scenarios. Based on this, this paper proposes a new method of rolling bearing fault diagnosis based on digital twin technology and improved convolutional neural network (CNN)-Transformer deep learning model. Firstly, the geometric characteristics and motion mechanism of rolling bearings are analyzed in depth, and a high-fidelity virtual twin model is established. A balanced simulation data set is generated by numerical simulation. Secondly, we improve the traditional CNN, combined with the Transformer deep learning framework, to enhance the ability of the network to extract features. By performing wavelet transform on the test data obtained from the rolling bearing acceleration test bench and the simulation data generated by the twin model, a dual-channel signal of parallel convolution is formed, and a fault diagnosis model based on dual-channel parallel CNN-Transformer is constructed. Finally, the effectiveness of the proposed method is verified by ablation experiments. The results show that the proposed method can accurately and efficiently identify different rolling bearing fault modes and has superior diagnostic performance. At the same time, the model can also be further extended to related fields to provide new ideas and technical references for fault diagnosis of other mechanical equipment.

Electroweak axion portal to dark matter

Axion-like particles (ALPs) are good candidates for mediators to the dark sector. We explore scenarios in which an ALP mediates interactions between dark matter and electroweak gauge bosons. These models yield testable electromagnetic signals in astrophysical, cosmological, and terrestrial probes. We find promising prospects for both indirect detection and accelerator tests, with interesting parameter space already constrained by current experiments. Our work provides concrete benchmarks for future tests of the electroweak ALP portal. Published by the American Physical Society 2024

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.

Age-Related Differences and Reliability of a Field-Based Fitness Test Battery in Young Trained Footballers: The Role of Biological Age.

the purpose of this study was to analyze the reliability of a field-based fitness test battery in young trained football players, according to biological age. 197 young trained football players (12-19 years old) participated in the study. We measured anthropometric measurements (i.e., height, sitting height, length leg, and body mass), a bilateral vertical jumping test (CMJ), a progressive loading test of squats and hip thrust, acceleration and speed tests (10 m and 30 m sprint tests), a change-of-direction ability test (V-cut test), and a cardiorespiratory fitness test (30-15 intermittent fitness test). Statistical data are shown as the mean ± standard deviation by PHV group in tests and retests. Test reliability was assessed through the intraclass correlation coefficient (ICC), with an ICC above 0.9 being considered high. To evaluate accuracy and repeatability, standard error of measurement, coefficient of variation, and minimum detectable change at 90% were determined and Bland-Altman diagrams were used, establishing a statistical significance of p < 0.05. All of the tests showed non-significant differences between the test and retest in the pooled sample (p > 0.05). Furthermore, all of them presented a trivial effect size (<0.2) and high intraclass correlation coefficients (>0.9), which indicates the high reproducibility of the tests, despite some of them presenting a significant difference between trials (i.e., the CMJ, 10 m sprint, V-cut, and squat tests). Low measurement errors were found for all tests (coefficient of variation [CV] = 4.39-9.39), except for the CMJ and the progressive loading test for squat and hip thrust exercises (CV = 12.2-21.11). Similar results were found irrespective of biological age group. All tests were reliable for the pooled sample as well as for the biological age groups.

An AAT technique based fatigue evaluation of composite corrugated steel web girders under coupled flexural load and temperature gradient

Medium-to-long spanned composite corrugated steel web (CSW) girders have recently been extensively constructed in the hot-humid terrains. Their degraded structural behavior in service has been concerning due to the presence of surface cracks under vehicle load-induced fatigue and repeated temperature fluctuation as coupled loads. This paper presents an experimental coupled loading study for such a structure with a CSW dimensional scale factor comparable to contemporary research work. An innovative artificial acceleration testing (AAT) technique was developed to fulfill the fatigue experimental test under controlled periodic variation of temperature. The structural deterioration modes during the whole fatigue loading progress have been analyzed. A new equation was proposed for the calculation of the coupled stress field incorporating the compatible strain condition at the steel-concrete interface under coupled loads. The resultant S-N relations based on fracture mechanics are demonstrated to be reasonably consistent with codified detail categories. The stress intensity factor allowing for crack geometry and the heat flux due to the prescribed temperature difference was developed and justified for the analytical remaining fatigue life analysis. The results can provide a reference for the development of AAT technology and the basic theory of thermal-structural analysis for these girders in the future.

An accelerated corrosion-fatigue testing method for marine high-strength steel based on equivalence principle of fatigue crack growth

The corrosion-fatigue test is widely used to assess marine equipment. However, due to the low-frequency and high-cycle loading of marine equipment in service, conventional test methods require long cycle times and high costs. This makes it challenging to meet the rapid evaluation demands associated with equipment development effectively. In this study, an accelerated corrosion test method was proposed for steel by adjusting the composition, temperature, pH and H2O2 concentration of environment. Fatigue crack growth tests were conducted under various corrosion environments and load frequencies. The matching relationships between corrosion fatigue acceleration multiplier, corrosion environment parameters and load parameters were established. Additionally, a corrosion fatigue acceleration test method was proposed based on the equivalent principle of fatigue crack growth. The results show that effective coupling between corrosion and fatigue can be achieved by gradually reducing the load frequency as the stress intensity factor amplitude increases throughout the crack growth process. It is consistent with the trend of fatigue crack growth rate in the seawater environment. The 4.85% fatigue life deviation and the 15.68 times corrosion fatigue acceleration can be achieved by our method. This work improves the accuracy and reliability of fatigue performance evaluation for offshore equipment.

A Newton-Cotes-based online acceleration signal fast processing approach to obtain displacement for digital twins

The timeliness and reliability of data monitoring gained the top priority due to the rapidity and precision of digital twins (DTs). This study proposes a novel fast and adaptive processing method for an online signal for DTs focused on the effectiveness and accuracy of signal processing. Based on the first-order Newton-Cotes interpolation, the initial acceleration monitored by the accelerometer is integrated online to obtain the corresponding velocity. To ensure the reliability of the integral velocity, an improved exponentially weighted moving average is simultaneously constructed to adaptively filter drift from the velocity point-to-point in real-time. Subsequently, the filtered velocity is integrated online to get the corresponding displacement. Meanwhile, to reduce the drift in the integral displacement, the envelope curves are employed to adaptively track the drift and improve the accuracy of the final integral displacement. Then, different types of acceleration test functions with different signal-to-noise ratios are used to verify the proposed method, illustrating that the robustness to noise, accuracy, and timeliness of the proposed method to signal is better than other methods. At the same time, the integration results from the accelerometer are compared by the monitoring displacement. Finally, the proposed method is applied in constructing airplane wing DTs to prove its feasibility for DTs. This study can provide technology for efficient adaptive filtering with less delay, and become a reference for the reliability and instantaneity of DTs from signal processing.

Vestibulometry, the registration of responses to stimulation of the vestibular organ with stimuli of different frequencies.

&lt;b&gt;Introduction:&lt;/b&gt; The vestibular organ (VO) is essential for maintaining balance and stabilizing visual images during head movements. To evaluate its function, the strength of the vestibulo-ocular reflex (VOR) is assessed using kinetic tests like the Sinusoidal Harmonic Acceleration Test (SHAT), video Head Impulse Test (vHIT), and slow-phase peak velocity (SPV) measurement in the caloric test (CT). Despite their limited sensitivity and specificity, they are used to determine eligibility for positions requiring strong balance control.&lt;b&gt;Aim:&lt;/b&gt; To determine the range of VOR gain in young healthy individuals in SHAT, vHIT and CT. To search for correlations between vestibular test results and age and gender of the subjects.&lt;b&gt;Materials and methods:&lt;/b&gt; Sixty two healthy individuals, with 32 males and 30 females, aged 7 to 33 who met the inclusion criteria were included in the study. Each participant underwent SHAT, vHIT and CT. Standard statistical methods and Spearman's rank correlation were used.&lt;b&gt;Results:&lt;/b&gt; The age of the subjects correlated negatively with the VOR gain in SHAT. There was no correlation between results for SHAT, vHIT or CT.&lt;b&gt;Discussion:&lt;/b&gt; Various factors, such as vestibular stimulation and anatomical variations, affect vestibular test results. While these tests complement each other in diagnosing vertigo, they are not recommended for healthy individuals qualifying for high-vestibular-performance occupations.&lt;b&gt;Conclusions:&lt;/b&gt; With age, the sensitivity of the VO to kinetic stimuli decreases. The inability to calibrate stimuli can result in varied responses among individuals. A comprehensive evaluation of the VO requires testing across different frequency ranges.

A general Bayesian algorithm for the autonomous alignment of beamlines.

Autonomous methods to align beamlines can decrease the amount of time spent on diagnostics, and also uncover better global optima leading to better beam quality. The alignment of these beamlines is a high-dimensional expensive-to-sample optimization problem involving the simultaneous treatment of many optical elements with correlated and nonlinear dynamics. Bayesian optimization is a strategy of efficient global optimization that has proved successful in similar regimes in a wide variety of beamline alignment applications, though it has typically been implemented for particular beamlines and optimization tasks. In this paper, we present a basic formulation of Bayesian inference and Gaussian process models as they relate to multi-objective Bayesian optimization, as well as the practical challenges presented by beamline alignment. We show that the same general implementation of Bayesian optimization with special consideration for beamline alignment can quickly learn the dynamics of particular beamlines in an online fashion through hyperparameter fitting with no prior information. We present the implementation of a concise software framework for beamline alignment and test it on four different optimization problems for experiments on X-ray beamlines at the National Synchrotron Light Source II and the Advanced Light Source, and an electron beam at the Accelerator Test Facility, along with benchmarking on a simulated digital twin. We discuss new applications of the framework, and the potential for a unified approach to beamline alignment at synchrotron facilities.

Pass-by noise regulation - Uncertainties reduction thanks to tire sound emission modelling

The UN regulation R51-03 on vehicle sound emissions enters its third phase in July 2024, with the challenging level of 68 dB(A) to achieve for most of passenger cars and light commercial vehicles. The Lurban indicator, as calculated in the regulation, is a weighted average of acceleration and constant rolling speed tests. Thus, the tire sound emissions represent by far the first contributor to the vehicle compliance. Therefore, it is crucial to understand how tire sound changes under the effects of speed, acceleration, or temperature. In this paper, a study on tire sound behavior is presented. It is based on repeated measurements of pass-by sound emissions of a set of tires, under various conditions of speed, acceleration, and ambient temperature. Among a huge variety of tire sound emission models, a regression algorithm is used to identify the model that fits the best to the measured tire sound emissions data. This tire sound emission model is then used to foresee the impacts of Regulation R51-03 updates, aiming at reducing the uncertainties induced by temperature and test track discrepancies, by correcting the tire sound contribution. The effects of this correction on the uncertainties can be anticipated by the model.

Detection model for network access data tampering attacks with blockchain technology

This paper studies the detection model of network access data tampering attack based on blockchain technology to solve the problem of over-dependence on central server and easy data tampering in traditional network environment. The model uses decentralization and encryption technology to monitor user behavior in real time through smart contracts, enhances data protection with SHA-256 hash algorithm, and combines consensus algorithm to ensure data consistency and security. The experimental results show that the model performs well in detecting multiple attack types with an accuracy of 99.51% and an F1 score of 0.98, far exceeding traditional methods and other deep learning techniques. The model shows good robustness under multi-node attacks, even with 200 attack nodes, the recognition accuracy is still close to 90%, and the response time is less than 3 seconds. Cross-platform testing showed that the model quickly and consistently detected tampering on both Ethereum and Hyperledger, with an average detection time between 0.33 and 0.47 seconds.The hardware acceleration test further shows that the processing speed and hardware utilization of TPU and GPU have been improved, with TPU processing speed reaching 135 MB/s and GPU 122 MB/s. This study will provide a theoretical basis for improving the security, effectiveness and reliability of current network systems, and also lay a solid theoretical and technical foundation for network applications in future network environments.

Experimental investigation of using Ultra-High-Performance Concrete coating for anti-corrosion protection of reinforced concrete induced by chloride ions

The emergence of Ultra High-Performance Concrete (UHPC) is one of the latest developments in concrete technology. Repairing and rehabilitating damaged structures by applying a thin layer of several centimeters on conventional concrete (with or without reinforcement) has been one of the applications of UHPC. Due to its very small porosity and excellent permeability, UHPC has extremely high durability against the penetration of destructive substances such as water, chloride ions, oxygen, etc. In this work, we investigated the durable effect against external aggressive corrosive substances by coating a 2.5 cm thickness layer of UHPC on conventional concrete. The desired composite concrete consists of a conventional concrete core with a compressive strength of 40 MPa and a coating with a thickness of 2.5 cm of UHPC cover. Then, this concrete went through oxygen penetration, Rapid Chloride Permeability Test (RCPT), and electrical resistance tests. Finally, to verify the results of the durability tests, two sets of comparison reinforced concrete specimens with 5 cm as their covers were exposed to an accelerated corrosion test. It is found that the substitution of a 2.5 cm layer of UHPC instead of the conventional concrete resulted in a 30-times increase in resistance against water penetration, 41 times against chloride ion penetration, 307 times against oxygen penetration, and 8 times in its electrical resistance. Based on corrosion acceleration test results, after 30 days of applying a current with a voltage of 31 volts, the control specimens with a 5 cm cover started to corrode after one week. After 30 days, 47 % corrosion was observed. Even though after 365 days, no signs of corrosion were found in the UHPC-coated specimens.

Effect of oxidizer on the energy release during the initial detonation stage of aluminized explosives

ABSTRACT The addition of an oxidizer to aluminized explosives can promote the reaction of the aluminum particles to release more energy, significantly increasing the energy of the explosion. In this study, metal plate acceleration tests of CL-20-based explosives under strong constraints were performed, and the metal plate velocity was measured by laser interferometry, then the metal plate acceleration processes were simulated. By combining experiment and numerical simulation, the metal acceleration characteristics of the initial detonation stage were obtained, and the energy release and aluminum reaction law of oxidizer-containing cast cured aluminized explosives were investigated. The results showed that, in the initial stage of the detonation product expansion, the energy released from the aluminum reaction in the explosives with an oxidizer was slower than that in the explosives without an oxidizer. As the oxidizer content increased, the acceleration ability decreased, and the energy utilization rate of the explosive decreased. This may be because of the relatively low CL-20 content and high oxidizer content, where the oxidizer does not participate in the initial reaction and absorbs a large amount of the heat released by the CL-20 reaction, resulting in weak acceleration ability in the initial detonation stage of aluminized explosives.