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Portevin–Le Chatelier effect, associated with dynamic strain aging, is widely found in various alloys, and the maximum serration magnitude from the tensile stress–strain curve can be considered as the point closest to the failure threshold. Due to the difficulty to define solute and solvent atoms in multicomponent alloys, it is a great challenge to explore the serration mechanism. In this study, the atoms that play the role of pinning are defined as solute atoms. Aided by mean-field theory, an in situ pinning model coupled with the twinning effect in a CoNiV alloy with low stacking fault energies is successfully established, which can well predict the failure threshold, i.e., the maximum serration magnitude. The present study paves a new way to correlate the serration dynamics and in situ pinning, and further predicts the failure threshold upon loading for multicomponent high- and medium-entropy alloys. [ABSTRACT FROM AUTHOR]

Background: Because spontaneous remission is common in IMN, and there are adverse effects of immunosuppressive therapy, it is important to assess the risk of progressive loss of renal function before deciding whether and when to initiate immunosuppressive therapy. Therefore, this study aimed to establish a risk prediction model to predict patient prognosis and treatment response to help clinicians evaluate patient prognosis and decide on the best treatment regimen. Methods: From September 2019 to December 2020, a total of 232 newly diagnosed IMN patients from three hospitals in Liaoning Province were enrolled. Logistic regression analysis selected the risk factors affecting the prognosis, and a dynamic online nomogram prognostic model was constructed based on extreme gradient boost, random forest, logistic regression machine learning algorithms. Receiver operating characteristic and calibration curves and decision curve analysis were utilized to assess the performance and clinical utility of the developed model. Results: A total of 130 patients were in the training cohort and 102 patients in the validation cohort. Logistic regression analysis identified four risk factors: course ≥ 6 months, UTP, D-dimer and sPLA2R-Ab. The random forest algorithm showed the best performance with the highest AUROC (0.869). The nomogram had excellent discrimination ability, calibration ability and clinical practicability in both the training cohort and the validation cohort. Conclusions: The dynamic online nomogram model can effectively assess the prognosis and treatment response of IMN patients. This will help clinicians assess the patient's prognosis more accurately, communicate with the patient in advance, and jointly select the most appropriate treatment plan. [ABSTRACT FROM AUTHOR]

Oral and maxillofacial trauma is influenced by various factors, including regional characteristics and social background. Due to the coronavirus disease 2019 (COVID-19) pandemic, a state of emergency was declared in Japan in March 2020. In this study, we aimed to examine the dynamics of patients with oral and maxillofacial trauma over a 12-years period using interrupted time-series (ITS) analysis. Patients were examined at the Shimane University Hospital, Maxillofacial Trauma Center from April 2012 to April 2023. In addition to general patient characteristics, data regarding the type of trauma and its treatment were obtained from 1203 patients (770 men and 433 women). Group comparisons showed significant differences in age, trauma status, method of treatment, referral source, route, and injury occasion. ITS analysis indicated significant changes in combined nasal fractures, non-invasive reduction, and sports injuries (P < 0.05), suggesting COVID-19 significantly impacted oral and maxillofacial trauma dynamics. A pandemic of an infectious disease may decrease the number of minor trauma cases but increase the number of injuries from outdoor activities, resulting in no overall change in the dynamics of the number of trauma patients. Medical systems for oral and maxillofacial trauma should be in place at all times, independent of infectious disease pandemics. [ABSTRACT FROM AUTHOR]

Background: Multiaxial dynamic loading situations occur in many industrial cases and multiaxial dynamic test development is thus a crucial issue. Objective: To meet this challenge, a biaxial compression Hopkinson set-up with four symmetric input bars is designed. Methods: The set-up consists of a vertical single striker, a sliding surface mechanism that transfers the impact energy to four horizontal tension bars, and four horizontal Hopkinson bars whose extremities are dynamically compressed by the previous tension bars. Strain gauges on two positions of each Hopkinson bar enable for force and displacement measurements at the bar-sample interfaces. Results: Simple and biaxial compression tests are carried out on cuboid and cross samples, and the sample material dynamic behavior is deduced from simple compression tests. Conclusions: The displacements are also estimated using digital image correlation, which confirms the previous measurements. The consistency of the global sample behavior identified from a biaxial compression test is checked by processing numerical simulations based on the behavior determined in simple compression. The results show that the experimental device can be used to identify any behavior law in dynamic biaxial compression. [ABSTRACT FROM AUTHOR]

Background: To evaluate the stability of jointed rock masses subjected to dynamic disturbance, laboratory dynamic shear test on rock joint is necessary. Developing dynamic shear test equipment for rock joint is currently a pressing issue. Objective: To address this issue, a new apparatus is developed to reproduce the shear-slip process of rock joint subjected to dynamic disturbance under various initial stress state. Methods: The disturbance load, which has a dominant frequency close to that of seismic waves, is generated by an electromagnetic-driven disturbance generator, and its amplitude and duration can be accurately controlled in a stable manner. The initial normal and shear stresses can be applied in the shear test under dynamic disturbance using servo-controlled loading unit, which facilitates the simulation of the real stress state of rock joint. Results: The shear tests under dynamic disturbance show that when an initial shear stress is applied to rock joint, an additional deformation stage of stress recovering can also trigger a slip displacement, which contributes to the destabilization of jointed rock masses. With increasing initial shear stress, the dynamic slip displacement, stress drop and post-disturbing deformation increase. The feasibility of the apparatus to conduct quasi-static direct shear tests with both the constant normal loading (CNL) and constant normal stiffness (CNS) boundaries is also verified. Conclusions: Test results demonstrate that using the new apparatus, shear-slip properties of rock joint subjected to dynamic disturbance can be tested in various initial stress states. [ABSTRACT FROM AUTHOR]

Recently, hydrostatic buffers have emerged as energy-absorbing components in railway vehicles. These buffers exhibit speed-dependent characteristics, with their reaction forces contingent upon compression displacement and speed. However, when dealing with a hydrostatic buffer with an unknown characteristic function in dynamic simulations, accommodating its speed-dependent attributes becomes a challenging task. In this study, we proposed a method for simulating train couplings that incorporates the speed-dependent characteristics of a hydrostatic buffer by utilizing a deep neural network (DNN). Our methodology involved the training of a DNN-based speed-dependent buffer model using empirical data obtained from dynamic buffer tests. Subsequently, this model was applied to a multibody dynamics simulation for train coupling analysis. A critical aspect of this study involved comparing speed-dependent and speed-independent models in a train coupling scenario. This comparison reveals a significant insight: neglecting speed-dependent characteristics in coupling simulations can lead to inaccurate train-coupling safety assessments. The DNN-based method demonstrated its effectiveness, even with limited test data and when the mathematical speed-dependent characteristic function of the buffer is unknown. [ABSTRACT FROM AUTHOR]

Revealing the damage mechanism of jointed rocks under a cyclic loading and formulating the corresponding dynamic constitutive model to meet the requirements for the evaluation of anti-vibration safety for critical engineering construction and operation is an essential, urgent and basic subject. Based on the breakage mechanics for geological material, jointed rock is considered as a binary-medium material composed of the bonded elements and frictional elements. The bonded elements are regarded as elastic-brittle elements, and the frictional elements are regarded as elastic-plastic elements. Firstly, the static binary-medium model for jointed rock is established based on the homogenization method and by introducing the breakage ratio and the strain concentration coefficient. Then, the dynamic binary-medium model for jointed rock under cyclic loads is established considering the nonlinear damage effect resulting from cyclic loads. The breakage ratio formula is improved, and the Drucker–Prager criterion is introduced. During the unloading stage, it is supposed that the breakage ratios and strain concentration coefficients remain unchanged and the stress–strain ratios of both bonded elements and frictional elements are constant. The model is verified by static and dynamic triaxial tests of jointed rock samples with an interpenetrated joint. It is found that the model can describe the nonlinear stress–strain characteristics of a jointed rock subjected to cyclic loads relatively well and can reflect the effects of cyclic loading on the deformation and damage, including the lateral deformation characteristics. Meanwhile, the typical three-stage (varying from sparse to dense to sparse) evolution laws of the stress–strain curves are also reflected relatively well. [ABSTRACT FROM AUTHOR]

Predicting breakthrough papers holds great significance; however, prior studies encountered challenges in this task, indicating a need for substantial improvement. We propose that the failure to capture the dynamic structural-evolutionary features of citation networks is one of the major reasons. To overcome this limitation, this paper introduces a new method for constructing citation cascades of focus papers, allowing the creation of a time-series-like set of citation cascades. Then, through a thorough review, three types of structural indicators in these citation networks that could reflect breakthroughs are identified, including certain basic topological metrics, PageRank values, and the von Neumann graph entropy. Based on the time-series-like set of citation cascades, the dynamic trajectories of these indicators are calculated and employed as predictors. Using the Nobel Prize-winning papers as a landmark dataset, our prediction method yields approximately a 7% improvement in the ROC-AUC score compared to static-based prior methods. Additionally, our method advances in achieving earlier predictions than other previous methods. The main contribution of this paper is proposing a novel method for creating citation cascades in chronological order and confirming the significance of predicting breakthroughs from a dynamic structural perspective. [ABSTRACT FROM AUTHOR]

This study investigated the effects of listening effort (LE) on balance in patients with compensated vestibular deficits compared to healthy peers. The subjects included two main groups: a control group of 15 healthy subjects and a study group of 19 patients with compensated vestibular pathology. The computerized dynamic posturography test (CDP) was conducted without the speech-in-noise task as a baseline, then the participant was subjected to a dual task in which the auditory task (speech-in-noise sentences) was given as the primary task, and the balance function test was the secondary task. The study group showed statistically significantly worse values of all body balance parameters under dual-task than the baseline in all conditions. These differences were much higher under the compliant platform conditions. However, these findings were not statistically significant in the control group. The study group showed a statistically significant decline in body balance reactions compared to the control group under dual-task with increased listening effort and the compliant platform. Study subgroup analysis revealed statistically significant differences between patients with unilateral vestibular loss (UVL) and those with bilateral vestibular loss (BVL) in the unstable platform condition. Our study regarding implementing a dual-tasking paradigm as a measure of LE during the evaluation of chronic vestibular patients with CDP demonstrated how dual-tasking with increased LE affects postural stability. Because of this, patients will probably be more prone to tripping and falling in multitasking situations, as found in real-world settings. This fact should be taken into consideration while testing patients with chronic vertigo and compensated states at VNG. A dual-task paradigm helps uncover the unrevealed pathology. [ABSTRACT FROM AUTHOR]

Background: Robotic devices are known to provide pivotal parameters to assess motor functions in Multiple Sclerosis (MS) as dynamic balance. However, there is still a lack of validation studies comparing innovative technologies with standard solutions. Thus, this study's aim was to compare the postural assessment of fifty people with MS (PwMS) during dynamic tasks performed with the gold standard EquiTest® and the robotic platform hunova®, using Center of Pressure (COP)-related parameters and global balance indexes. Methods: Pearson's ρ correlations were run for each COP-related measure and the global balance index was computed from EquiTest® and hunova® in both open (EO) and closed-eyes (EC) conditions. Results: Considering COP-related parameters, all correlations were significant in both EO (0.337 ≤ ρ ≤ 0.653) and EC (0.344 ≤ ρ ≤ 0.668). Furthermore, Pearson's analysis of global balance indexes revealed relatively strong for visual and vestibular, and strong for somatosensory system associations (ρ = 0.573; ρ = 0.494; ρ = 0.710, respectively). Conclusions: Findings confirm the use of hunova® as a valid device for dynamic balance assessment in MS, suggesting that such a robotic platform could allow for a more sensitive assessment of balance over time, and thus a better evaluation of the effectiveness of personalized treatment, thereby improving evidence-based clinical practice. [ABSTRACT FROM AUTHOR]

The field load test is a direct and effective method for evaluating the performance of bridge structures. However, the existing bridge static load tests on site are costly, inefficient, and obstruct traffic; moreover, improper loading may also cause some damage to the bridge structure. This paper proposes a random model update method based on bridge dynamic load tests and the Bayesian inference as an alternative to the static load test. The Gaussian process model was used instead of the finite element model to reduce the cost of model calculation. Furthermore, choose the Markov Chain Monte Carlo (MCMC) method based on delay rejection adaptive Metropolis algorithm for Bayesian inference to improve the speed of the Bayesian method inferring the posterior probability density of updated parameters. First, the parameters to be updated for the bridge structure analysis model were determined based on the global sensitivity analysis method. Second, a uniform design sampling method was used to establish the Gaussian process optimization model to update the random model of the bridge structure. Finally, a reinforced concrete truss arch bridge was used to verify the correctness of the static load results of the bridge predicted by the random model update method based on dynamic load testing and Bayesian inference. The results show that the predicted results of the bridge static load test based on the dynamic load test and Bayesian reasoning method have an excellent agreement with the measured results, and this method can effectively overcome the adverse effects of the existing bridge static load test. [ABSTRACT FROM AUTHOR]

Pointing error is a critical performance metric for vehicle-mounted single-photon ranging theodolites (VSRTs). Achieving high-precision pointing through processing and adjustment can incur significant costs. In this study, we propose a cost-effective digital correction method based on a piecewise linear regression model to mitigate this issue. Firstly, we introduce the structure of a VSRT and conduct a comprehensive analysis of the factors influencing its pointing error. Subsequently, we develop a physically meaningful piecewise linear regression model that is both physically meaningful and capable of accurately estimating the pointing error. We then calculate and evaluate the regression equation to ensure its effectiveness. Finally, we successfully apply the proposed method to correct the pointing error. The efficacy of our approach has been substantiated through dynamic accuracy testing of a 450 mm optical aperture VSRT. The findings illustrate that our regression model diminishes the root mean square (RMS) value of VSRT's pointing error from 17″ to below 5″. Following correction utilizing this regression model, the pointing error of VSRT can be notably enhanced to the arc-second precision level. [ABSTRACT FROM AUTHOR]

Aiming at the problem that the traditional analysis methods such as Zoom-FFT (ZFFT) heavily depend on the data length in the frequency separation accuracy when separating the unbalanced signals of the inner and outer rotors of the dual-rotor system with micro-speed difference, an improved method based on ZFFT + FT was proposed to refine the signal spectrum and accurately identify the unbalanced response of the inner and outer rotors. On the basis of sampling and filtering the micro-speed difference signal by ZFFT, DFT was used to refine the frequency segment, so as to extract the corresponding amplitude of the operating frequency components of the inner and outer rotors. The basic principles of Chirp-Z transform (CZT), ZFFT, and ZFFT + FT algorithms were introduced, and the corresponding programs of each algorithm were written based on LabVIEW software for simulation, then the signal generator was used to carry out the micro-speed difference signal extraction test and finally the dynamic balance test was carried out on the dual-rotor test bench. Data simulation and field test show that compared with the CZT and ZFFT methods, the method has better frequency resolution ability and can separate the micro-speed difference signal with higher accuracy, and has high feasibility and practicability in the dynamic balance of the micro-speed difference dual-rotor system. [ABSTRACT FROM AUTHOR]

Elastomeric isolation bearings exhibit complex coupled horizontal-vertical behavior. Most existing macroscopic models simulate the quasistatic test results well but have deficiencies in simulating the dynamic behavior of bearings. In this paper, the experimental observations of previous dynamic bearing tests were investigated. The simulation capacity of existing macroscopic models was checked by comparison with the test data. The results show that the calculated axial load and hysteresis loops exhibit undesired oscillations under dynamic excitation. The intrinsic deficiency of existing models in simulating the dynamic response of a bearing was identified as the coupling or off-diagonal terms in the tangent stiffness matrix and the variation of vertical stiffness of the model. Motivated from this key observation, a new macroscopic model was developed to account for the dynamic behavior of bearings, followed by the suggestion of its numerical implementation. Through the introduction of a new axial load expression, the tangent stiffness matrix of the new model was semidecoupled, and the vertical stiffness of the new model remains unchanged, which reduced the interaction between the horizontal and vertical behavior. The simulation capacity of the new model was then validated by comparison with previous test data. The results show that the new model effectively captures the axial load variation and hysteresis loop of the bearings under dynamic excitations. Moreover, it was found that the consideration of the bearing height improved the simulation accuracy, and the size effect of the bearing is critical for isolated structures with large bearing-to-superstructure-height ratio, such as low- to medium-span bridges. [ABSTRACT FROM AUTHOR]

State of charge (SOC) is a key state variable in lithium‑ion battery management system. The battery model and estimation algorithm are important factors that affect the accuracy of SOC estimation. In this paper, the optimization battery model is created by optimizing the hybrid power pulse characteristic (HPPC) parameter combination through orthogonal analysis. The simulation results demonstrate that optimizing the HPPC parameter combinations can improve battery modeling accuracy. Then, an extended Kalman particle filter (EKPF) algorithm is proposed by using the extended Kalman filter (EKF) algorithm as the density function of the particle filter (PF) algorithm. The EKPF algorithm is verified under the dynamic stress test and Beijing bus dynamic stress test conditions, the root mean absolute errors and root mean square errors in all cases are less than 1.5%. The experimental results show that the EKPF algorithm can combine the advantages of EKF and PF to estimate lithium‐ion battery SOC accurately. [ABSTRACT FROM AUTHOR]

This article contains the results of research on the development of a Cf/C-UHTC carbon fabric composite based on a viscose precursor and a combined matrix consisting of partially sintered ceramics in a system consisting of HfCeHfB2eNbCeNbB2eTiCeTiB2eB4CeSiC, amorphous carbon, and pyrocarbon. The SiC fraction does not exceed 8.5e9.0 wt%. In its initial state, the composite has open porosity, with apparent and true densities of 18e22%, 2.25e2.29 g/cm³ and 2.79e2.91 g/cm³, respectively. The bending strength and the elasticity modulus are 27.8 ± 0.7 MPa and 7.8 ± 0.2 GPa, respectively, and the fracture strain is 0.85 ± 0.05%. The tests for resistance to oxidation and ablation were carried out in a gas dynamic flow regime and non-equilibrium air plasma heating at flow rates of 4.5e4.8 km/s and breaking enthalpy of 45 e50 MJ/kg. Heating was performed in the temperature range Tw = 1400e2700 °C at the critical point on the front surface of the samples. The average linear ablation rate and mass loss rate of the composite are 6.3 ± 0.3 mm/s and 6.22 ± 0.44 mg/s. The estimated value of the conductivity factor is 0.280e0.285 W/(m K). The performance ability of the composite arises from the formation and evolution of a passivating heterogeneous oxide film consisting mainly of titanium niobate Ti2Nb10O29, mixed solutions of Hf1-xTixO2, (Ti1-xHfx)1-yNbyOz and (Ti1-xHfx)NbO4 with broad homogeneity ranges, and also encapsulated carbide and boride particles. It is shown that the oxidation resistance of the composite increases as a result of the transition through a number of phases into a liquid state as the working temperature increases. [ABSTRACT FROM AUTHOR]

The mechanical properties of cooperative system bridges are complex. This paper describes the construction monitoring and load tests of a cable-stayed and arch cooperative bridge. The cable force, girder stress and arch alignment were monitored during construction to ensure the safety of the bridge structure and attain the intended internal force state in the completed bridge. Static and dynamic load tests were performed after completing the bridge to test its bearing capacity. The construction monitoring observations indicated that the cable force and suspender force change of the bridge during construction were generally consistent with theoretical calculations. The measured cable force of cable C01 was between 2155 and 3085 kN, and the measured value of suspender LS15 was between 980 and 1250 kN; these values conform to the laws of mechanics. The load test results demonstrated that the maximum deflection of the mid-span section of the girder was 5.8 mm, which was less than the theoretical value (6.3 mm). The measured impact coefficients of the bridge under four sets of working conditions based on dynamic load testing were similar to the computed results. These results confirm that the girder has sufficient structural stiffness. [ABSTRACT FROM AUTHOR]

To determine whether cognitive learning potential measured with the dynamic Wisconsin Card Sorting Test has added value in predicting rehabilitation outcome in elderly patients post-stroke after controlling for age, ADL independence at admission, global cognitive functioning and depressive symptoms. Participants were patients with stroke admitted to a geriatric rehabilitation unit. ADL independence (Barthel Index) at discharge was used as measure for rehabilitation outcome. Predictor variables included age, ADL independence at admission, global cognitive functioning (Montreal Cognitive Assessment), depressive symptoms (Geriatric Depression Scale) and cognitive learning potential measured with the dWCST. Thirty participants were included. Bivariate analyses showed that rehabilitation outcome was significantly correlated with ADL independence at admission (r = 0.443, p = 0.014) and global cognitive functioning (r = 0.491, p = 0.006). Regression analyses showed that the dWCST was not an independent predictor of rehabilitation outcome. ADL independence at admission was the only significant predictor of rehabilitation outcome (beta = 0.480, p = 0.007). Cognitive learning potential, measured with the dWCST has no added value in predicting rehabilitation outcome in elderly patients post-stroke. ADL independence at admission was the only significant predictor of rehabilitation outcome. Trial NL7947. [ABSTRACT FROM AUTHOR]

Through a series of static mechanical tests and (SHPB) dynamic impact tests, the static and dynamic mechanical parameters of rock as represented by yellow sandstone are determined, and the Holmquist-Johnson-Cook model parameters of the rock are calibrated using the test data and theoretical calculations. The feasibility of a numerical model is verified, and numerical analysis of the SHPB impact process under different radial pressure pre-loading is carried out on the basis of good verification. The results show that with increasing impact load, the degree of rock breakage increases, as does the dynamic tensile strength. With the application of increasing pre-static pressure, the dynamic tensile strength of the rock decreases gradually, and the maximum radial cumulative strain increases continuously under a given impact pressure, indicating that micro-cracks in the rock develop initially and then expand under the influence of pre-static pressure; the rock is more easily broken, and its weakening degree increases. Under coupled dynamic and static loading, the energy utilization rate of rock in the Brazilian splitting process is jointly affected by axial compression ratio and impact load. Too large a pressure ratio will reduce the strain-rate sensitivity of rock, resulting in low energy utilization rate, while too low an axial compression ratio will make the dynamic tensile strength of rock relatively high, which is not conducive to tensile failure. Therefore, on the premise of clear fracture form requirements, a suitable combination of axial compression ratio and impact velocity can improve the rock crushing effect and energy utilization rate. [ABSTRACT FROM AUTHOR]

In order to effectively improve the seismic and impact resistance performance of soft rock tunnels, a composite support method was proposed and validated in the paper. The UDEC (Universal Distinct Element Code) model of soft rock layers was established, and the movement and subsidence characteristics of the roof and floor of the rock layers under impact loads was simulated and calculated. As a result, a composite support scheme with good cushioning performance was proposed. The top and sides of the tunnel were supported by a combination of anchor rods of different lengths and metal mesh, reinforced by steel beams and vibration absorbing filler around. The anchor rod was designed as a segmented loading structure, and can be set to different preloading forces based on the internal deformation of the rock layer. The dynamic response testing scheme was designed, and the results indicate that the segmented loading anchor rod has a significant buffering effect on the response to impact load, and can provide reasonable tension feedback at different stages. Research has found that when the water cement ratio is 0.5-1.5, the curing efficiency and strength are both higher. In order to compare the seismic performance of composite support and traditional constant resistance anchor rod support, local blasting experiments were conducted. Based on a blasting vibration tester, a data detection and transmission system were designed to obtain the vibration speed of the tunnel roof during the vibration process. The research results show that composite support can reduce the maximum vibration by more than 40 %, stabilize the fragmentation coefficient at 1.38, and have a very significant vibration reduction effect. [ABSTRACT FROM AUTHOR]

Objective. The Elekta unity MR-linac delivers step-and-shoot intensity modulated radiotherapy plans using a multileaf collimator (MLC) based on the Agility MLC used on conventional Elekta linacs. Currently, details of the physical Unity MLC and the computational model within its treatment planning system (TPS) Monaco are lacking in published literature. Recently, a novel approach to characterize the physical properties of MLCs was introduced using dynamic synchronous and asynchronous sweeping gap (aSG) tests. Our objective was to develop a step-and-shoot version of the dynamic aSG test to characterize the Unity MLC and the computational MLC models in the Monaco and RayStation TPSs. Approach. Dynamic aSG were discretized into a step-and-shoot aSG by investigating the number of segments/sweep and the minimal number of monitor units (MU) per segment. The step-and-shoot aSG tests were compared to the dynamic aSG tests on a conventional linac at a source-to-detector distance of 143.5 cm, mimicking the Unity configuration. the step-and-shoot aSG tests were used to characterize the Unity MLC through measurements and dose calculations in both TPSs. Main results. The step-and-shoot aSGs tests with 100 segments and 5 MU/segment gave results very similar to the dynamic aSG experiments. The effective tongue-and-groove width of the Unity gradually increased up to 1.4 cm from the leaf tip end. The MLC models in RayStation and Monaco agreed with experimental data within 2.0% and 10%, respectively. The largest discrepancies in Monaco were found for aSG tests with >10 mm leaf interdigitation, which are non-typical for clinical plans. Significance. The step-and-shoot aSG tests accurately characterize the MLC in step-and-shoot delivery mode. The MLC model in RayStation 2023B accurately describes the tongue-and-groove and leaf tip effects whereas Monaco overestimates the tongue-and-groove shadowing further away from the leaf tip end. [ABSTRACT FROM AUTHOR]

The goal of this paper is to improve the mechanical strength-to-weight ratios of metal cubic lattice structures using unit cells with fillet shapes inspired by triply periodic minimal surfaces (TPMS). The lattice structures here presented were fabricated from AA6082 aluminum alloy using lost-PLA processing. Static and dynamic flat and wedge compression tests were conducted on samples with varying fillet shapes and fill factors. Finite element method simulations followed the static tests to compare numerical predictions with experimental outcomes, revealing a good agreement. The TPSM-type fillet shape induces a triaxial stress state that significantly improves the mechanical strength-to-weight ratio compared to fillet radius-free lattices, which was also confirmed by analytical considerations. Dynamic tests exhibited high resistance to flat impacts, while wedge impacts, involving a high concentrated-load, brought out an increased sensitivity to strain rates with a short plastic deformation followed by abrupt fragmentation, indicating a shift towards brittle behavior. [ABSTRACT FROM AUTHOR]

This paper deals with determining degradation changes in alkaline-activated slag-based building materials. It describes methods for determining dynamic elastic moduli obtained by acoustic non-destructive methods, including the ultrasonic pulse method and the resonance method. A finegrained mortar was chosen as the initial mix for the implementation of the experiment, the binder part of which was sodium hydroxide-activated blast-furnace granulated slag. Beams with dimensions of 40 × 40 × 160mm were chosen as test bodies, for which acoustic non-destructive methods monitored changes in the material structure during degradation processes. [ABSTRACT FROM AUTHOR]

The objective of this study was to 1) compare the stress corrosion coefficient (n) of a Y-TZP obtained by two fatigue tests: cyclic and dynamic and 2) evaluate the effect of frequency in the characteristic lifetime and the existence of interaction between the cyclic fatigue and slow crack growth. A total of 145 Y-TZP specimens were produced in accordance with the manufacturer's instructions. These specimens, measuring 4.0 × 3.0 × 25.0 mm, were used for dynamic (n = 70) and cyclic fatigue tests (n = 75). The specimens were obtained from CAD/CAM blocks, sectioned, and sintered in a furnace at 1530 °C with a heating rate of 25 °C/min. They were tested in their "as-sintered" form without any additional surface treatment. The fatigue tests were conducted using a four-point bending to obtain the slow crack growth parameters (n). The cyclic fatigue test was also conducted in two frequencies (2 and 10 Hz), using stress levels between 350 and 600 MPa. Data from these tests were analyzed using ASTM C 1368–00 formulas and Weibull statistics. Scanning electron microscope (SEM) was used for fracture surface analysis to identify the origin of the fracture. Critical defect size was measured and used, along with flexural strength values, to estimate fracture toughness. Dynamic fatigue test data were used to obtain subcritical crack growth (SCG) parameters and perform Weibull statistical analysis. The cyclic fatigue data were used in the General Log-linear Model equation using the ALTA PRO software. Data were analyzed using one-way ANOVA followed by Tukey post-hoc tests and Student's t-test at a significance level of p ≤ 0.05. In the dynamic fatigue test, the values obtained for σ fo and n were 667 and 54, respectively. This parameter indicates how the strength of the material diminishes over time due to internal cracks. The Weibull parameters obtained from the same test results were m = 7.9, σ 0 = 968, 9 and σ 5% = 767, which indicates the reliability of the material. The Weibull parameters obtained by cyclic fatigue were statistically similar for the two frequencies used, the m * was 0.17 (2 Hz) and 0.21 (10 Hz); characteristic lifetimes (η) were 1.93 × 106 and 40,768, respectively. The n values obtained by cyclic fatigue were 48 and 40 at frequencies of 2 and 10 Hz, respectively. There was no effect of the frequency, the stress level or the interaction of the two in the Y-TZP lifetime, when analysed by General Log Linear Model. the n values obtained by cyclic and dynamic fatigue tests showed no statistically significant difference and the effect of frequency in the characteristic lifetime and the existence of interaction between the cyclic fatigue and subcritical growth were not observed in the tested specimens. • The type of fatigue test did not affect the coefficients of susceptibility to subcritical growth (n) for a dental Y-TZP. • The frequency used in the cyclic fatigue test had no influence on the fatigue parameters of the Y-TZP tested. • There was an increase in the defect size with decreasing loading rate, which explains the drop in strength. [ABSTRACT FROM AUTHOR]

The paper presents the performance enhancement of band-pass filter-based M-class phasor estimation. The performance of the M-class phasor estimation using a band-pass FIR filter is enhanced with a magnitude correction factor for the off-nominal frequency range. The band-pass filter is implemented for the phasor estimation with various window functions Tukey, Rife Vincent class-I order-2 (RV2), Hamming, Hanning, Blackman, and Flat-top (FT) and its performance are evaluated under the steady and dynamic state tests prescribed by the standard. A rigorous performance analysis of enhanced phasor estimation using band-pass FIR filter with various window functions is presented with the accuracy indices of total vector error (TVE), frequency error (FE), and rate of change of frequency error (RFE). The result analysis reveals that the performance enhanced phasor estimation using band-pass FIR filter offers significantly less error than reported work at the low sampling rate. The design and performance analysis of the phasor estimation using the band-pass FIR filter is performed in the MATLAB platform. [ABSTRACT FROM AUTHOR]

The indicators of dynamic qualities that ensure the traffic safety, as well as the permissible impact on the railway track, with the obligatory fulfillment of which the railway rolling stock can be used in the transportation process, are presented in this article. The purpose of this work was to carry out the complex dynamic (running), and the impact on the railway track, tests of the rolling stock, during which simultaneous registration of dynamic processes on the railway rolling stock, and in the elements of the superstructure of the track, is carried out, as well as in elements of turnouts. Dynamic tests were carried out on the track switches from the minimum speed to the maximum possible speed of 50 km/h by the TE33A diesel locomotive during the freight traffic. Meeting the requirement of reproducibility of test conditions and having a typical design of the track structure on wooden or reinforced concrete sleepers. [ABSTRACT FROM AUTHOR]

This paper presents the results of field tests performed to investigate the bearing capacity of Drilling with a prestressed concrete (DPC) pipe pile under different end sealing and side grouting conditions. The High Strain Dynamic Testing (HSDT) was conducted to evaluate the bearing characteristics of full-scale DPC pipe piles. Moreover, base resistance theoretical formula considering end sealing effect and shaft resistance theoretical formula considering side grouting effect are presented. The theoretical results were compared with the recommended values of specification for traditional pipe piles and tested values to demonstrate the rationality of theoretical formulas and the superiority of end sealing and side grouting. Furthermore, the effects of sediment under the sealing concrete and grouting conditions on the bearing capacity of a single pile were discussed in detail to reveal the influencing mechanisms of end sealing and side grouting. The result showed that the presented base resistance theoretical formulas can estimate the effect of end sealing on the ultimate base resistance of DPC pipe piles with good accuracy. For 1 m pipe piles, end sealing increases the base resistance by up to 103.5% at most compared to unsealing pipe piles; total shaft resistance of piles with double or multi-pipe grouting is more than 37% higher than the recommended maximum value of traditional pipe piles in the pile foundation specification. In addition, the base resistance was significantly affected by the sediment thickness under the sealing concrete. The hole wall time-dependent deformation caused by drilling and unloading affected the side grouting significantly. [ABSTRACT FROM AUTHOR]

The extractants diphenyl-N,N-dioctylcarbamoylmethylphosphine oxide and diphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide for the SNF reprocessing were tested. The conditions for extraction and separation of uranium and TPE–REE were determined. A flowsheet was proposed for reprocessing SNF from high-temperature gas-cooled reactors. Upon dynamic testing, at least 99.9% of uranium and plutonium and at least 99.5% of americium and rare earth elements were separated. The TPE + REE and U + Pu fractions were recovered. The U + Pu fraction contained approximately 5% Am, while the TPE + REE fraction had less than 0.1% U and Pu. [ABSTRACT FROM AUTHOR]

The article presents the results of studies on composition optimization, properties, and laboratory dynamic tests of extraction mixtures based on p-isononylcalix[6]arene for the alkaline HLW purification to remove 137Cs. The distribution of 137Cs among the products of the technological scheme is presented and the raffinate purification factor to remove 137Cs are determined. It was revealed that, in the case of using nitric acid as a stripping solution, nitrosation of p-isononylcalix[6]arene is possible in the technological process. The composition of the resulting product was determined. To prevent nitrosation of p-isononylcalix[6]arene, formic acid was used in the stripping stage, which ensured stable operation of the extraction setup for 48 h while 137Cs extraction from model alkaline HLW was at a level of 99.7%. [ABSTRACT FROM AUTHOR]

Stiffness quantification of unbound granular materials (UGMs) is essential for designing pavement structures. This stiffness can be determined directly through the resilient modulus test, or indirectly, by correlation, with the California bearing ratio (CBR) test. Alternatively, the dynamic CBR test (dCBR) has been proposed as a simple and low-cost method for this assessment. This study investigated a new dCBR test protocol based on a novel strain-stage approach, applying 20 load cycles/stage. This testing protocol is expected to facilitate characterization and on-site control of stiffness for UGMs, including marginal granular materials (MGMs). The study characterized four MGMs using the new dCBR test protocol and the resilient modulus test; four replicate specimens manufactured by gyratory compaction were assessed per material and test. The protocol was implemented successfully for the MGMs studied to compute an equivalent resilient modulus. A methodology is proposed for calculating an adjusted equivalent resilient modulus with values similar to those of the resilient modulus. Further research is suggested to explore the relationship between the dCBR and CBR tests to advance the characterization of granular materials for pavement structures and expand the experimental data using a broader set of soils to validate the protocol. [ABSTRACT FROM AUTHOR]

To (i) determine whether accelerated long-term forgetting (ALF) can be found using standardized verbal memory test materials in children with genetic generalized epilepsy (GGE) and temporal lobe epilepsy (TLE), and (ii) to establish whether ALF is impacted by executive skills and repeat testing over long delays. One hundred and twenty-three children aged 8 to 16, (28 with GGE, 23 with TLE, and 72 typically developing; TD) completed a battery of standardized tests assessing executive functioning and memory for two stories. Stories were recalled immediately and after a 30-min delay. To examine whether repeat testing impacts long-term forgetting, one story was tested via free recall at 1-day and 2-weeks, and the other at 2-weeks only. Recognition was then tested for both stories at 2-weeks. Children with epilepsy recalled fewer story details, both immediately and after 30-min relative to TD children. Compared to TD children, the GGE group, but not the TLE group, showed ALF, having significantly poorer recall of the story tested only at the longest delay. Poor executive skills were significantly correlated with ALF for children with epilepsy. Standard story memory materials can detect ALF in children with epilepsy when administered over long delays. Our findings suggest that (i) ALF is related to poor executive skills in children with epilepsy, and (ii) repeated testing may ameliorate ALF in some children. [ABSTRACT FROM AUTHOR]

Present study focused on to investigate the impact of end friction and lateral inertia on the dynamic properties of concrete obtained by performing the dynamic compression test on developed split Hopkinson pressure bar (SHPB) setup. The standard (SC) and high-strength concrete (HSC) exhibiting characteristic compressive strength of 35 and 60 MPa, respectively used in the present investigation. The concrete specimens with 29.5 and 45 mm diameter describing the aspect ratio about of 1 and 0.67, respectively, has been subjected to strain rates ranging from 78 to 336 s−1. The systematic experimental analysis of the influence of strain rate, end friction, and lateral inertia has been performed on the dynamic compressive properties. The influences of these factors on the dynamic compressive strength (DCS) and dynamic increase factor (DIF) have been discussed thoroughly. The results findings confirmed that as the strain rate rises, the dynamic characteristics of concrete also escalate. This is explained by the observed variations in DIF, which fall within the ranges of 1.76–2.65 for standard concrete (SC) and 1.28–1.70 for high-strength concrete (HSC). It was also confirming that the sensitivity of lateral inertia and end friction confinement is influenced by both the specimen diameter and strain rate. The lateral inertia confinement in larger diameter specimens significantly increases the DIF. In addition, the presence of end friction at the specimen bar interface also constrains the lateral deformation and significantly increases the DIF μ ≠ 0 , but there was no visible effect of specimen diameter was observed on the DIF μ = 0 of the concrete. [ABSTRACT FROM AUTHOR]

The contact wire wear is an important parameter to ensure the safety operation of electric railways. The contact wire may break if the wear is serious, which leads to transportation interruptions. This study proposes an optical measurement method of contact wire wear, using stereovision technology. The matching method of stereovision based on line-scan cameras is proposed. A lookup-table method is developed to exactly determine the image resolution caused by the contact wire being in different spatial positions. The wear width of the contact wire is extracted from catenaries' images, and the residual thickness of the contact wire is calculated. The method was verified by field tests. The round-robin tests of the residual thickness at the same location present excellent measurement repetitiveness. The maximum difference value between dynamic test results and ground measurement results is 0.13 mm. This research represents a potential way to implement condition-based maintenance for contact wire wear in the future in order to improve the maintenance efficiency and ensure the safety of catenary infrastructure. [ABSTRACT FROM AUTHOR]

This paper investigates the inherent nonlinear damping characteristics of a rotary eddy-current damper (RECD) and evaluates its vibration control performance on a single-degree-of-freedom (SDOF) system subjected to harmonic and seismic excitations. First, a RECD prototype was manufactured to experimentally identify its intrinsic nonlinear eddy-current damping characteristics. A magic formula model is then proposed to characterize the relationship between the eddy-current damping force and the velocity of the RECD, and its applicability in depicting the nonlinear damping characteristics of the RECD is evaluated by comparing with the electromagnetic finite-element (FE) model and the commonly used Wouterse’s model. Moreover, by comparing the experimental and analytical frequency–domain responses of an SDOF structure equipped with a RECD, the applicability of the magic formula model in evaluating the structural vibration control performance of the RECD is further verified. Finally, the control performance of the RECD for an SDOF structure subjected to earthquake ground motions is numerically evaluated and compared. Results show that the eddy-current damping force of the RECD presents obvious nonlinear characteristics with increasing velocity, and the proposed magic formula model can adequately depict the nonlinear eddy-current damping characteristics of the RECD. Moreover, the RECD exhibits superior structural control performance under harmonic and seismic excitations. [ABSTRACT FROM AUTHOR]

This study used centrifuge model tests to evaluate the dynamic behavior of piles and sloped ground. Two types of test models were created based on the ground's saturation. The researchers calculated p-y loops to analyze the dynamic interaction between piles and sloped ground, which can lead to liquefaction. In the dry sand model, the passive earth pressure of the slope greatly influenced pile behavior, while in the saturated sand model with liquefaction, the kinematic force of the slope had a significant effect. The study also derived a p-multiplier that can be applied to medium-dense soil based on the experimental results. [ABSTRACT FROM AUTHOR]

In this study, the traditional mini split Hopkinson tension bar (SHTB) was enhanced for the dynamic mechanical performance testing of single fiber/resin interface of composites. Single Aramid III fibers were modified using a polyamine modification treatment. Quasi-static and dynamic tensile tests of modified single Aramid III fibers were conducted using an electronic tensile testing machine and mini SHTB. The test results indicated that the surface modification employing the Catechol-Tetraethylenepentamine (Cat-TEPA) approach had a negligible effect on the tensile mechanical properties of single Aramid III fibers. The microdroplet method was introduced to measure the dynamic interfacial shear strength (IFSS) of Aramid III fiber/waterborne polyurethane resin using a mini SHTB. The dynamic shear test results revealed an increase in the dynamic shear strength of the modified Aramid III fiber/resin interface from 36.16 MPa to 41.51 MPa. Furthermore, the Scanning Electron Microscope (SEM) photography of the modified single Aramid III fiber after debonding exhibited regular grid structures on the debonding area, which can prevent debonding between the single fiber and the microdroplet, thereby enhancing interfacial shear performance. [ABSTRACT FROM AUTHOR]

The aim of the study was to optimize the seat for a personal vehicle equipped with a crankset mechanism, meant for everyday use. The inclination of the seat backrest was selected on the basis of theoretical considerations. Then dynamic tests were carried out on a group of young, healthy men in order to verify the ergonomic aspects of the seat position in relation to the crankset and determine the efficiency of the human-mechanism system with a load of 50 W. The data obtained from the dynamic tests were subject to statistical analysis. Research has shown that higher seat positions result in statistically higher efficiencies. In addition, a holistic analysis of the personal vehicle design problem shows that the upper position of the seat is also the best. The results of the research can be used to optimize personal vehicles using human force as a drive. [ABSTRACT FROM AUTHOR]

Under the repeated action of aircraft taxiing load, the subgrade plastic deformation becomes the key factor affecting the service performance of the airfields when salinized silt is used to fill the subgrade. In this study, the dynamic triaxial tests were carried out on a region in the northern part of China to study the effects of different salt contents on the dynamic characteristics of silt under cyclic loading. A prediction model for the salinized silt dynamic strength with a plastic strain of 4% as the failure criterion for the subgrade was thus proposed. It is found that with the increase of dynamic stress amplitude, the salinized silt plastic deformation transforms gradually from plastic deformation to incremental failure. The salt contents significantly influence the plastic strain and critical dynamic stress of silt. The strength of the salinized silt specimen is related to the ion concentration in the soil pores and the arrangement pattern of soil particles, as indicated by the progressive strength increase of the salinized silt at the low salt content of 1% and a further gradual decrease at high salt content. [ABSTRACT FROM AUTHOR]

There are differences between the dynamic deflection and bending moment (strain) in the same section of continuous girder bridges. However, the selection of the response for calculating dynamic amplification factors (DAFs), which are essential for bridge health monitoring and safety assessment, remains controversial. Modes may play a role in the relationship between the deflection DAF and the bending moment DAF in both numerical analysis and field tests. To investigate the distinctions between the DAFs of the deflection and bending moment in a continuous girder bridge, functional expressions of the DAFs were derived, taking into account multi-factor coupling under concentrated forces. The interaction effects of the mode and road surface condition (RSC), vehicle speed, bridge span length, and span number on the deflection DAF, the bending moment DAF, and the ratio of the deflection DAF to the bending moment DAF (RDM) of precast continuous box-girder bridges were analyzed using vehicle-bridge interaction. To ensure the accuracy of the DAF in numerical computations and experimental tests, two types of accuracy indexes and the corresponding cut-off modes were provided. Validation was conducted by performing dynamic load tests on two field bridges. The results indicate that different modes have a significant effect on the RDM of the mid-span section of a bridge. When considering multiple factors, the deflection DAF and bending moment DAF of the mid-span section increased rapidly with the considered modes and then stabilized. Statistically, the RDM of all nine bridges ranged from 1.00 to 1.12, indicating that the deflection DAF was greater than the bending moment DAF. The suggested cut-off modes can be utilized for efficient and accurate calculation of the DAF and response signal fidelity. [ABSTRACT FROM AUTHOR]

Objective: Overnight metyrapone test (OMT) is a dynamic test used to diagnose secondary adrenal insufficiency (SAI). Data on OMT use and its safety are scarce. We aimed to describe the indications and safety of outpatient OMT and compare OMT to the cosyntropin stimulation test (CST). Design: Single‐centre retrospective study of adult patients undergoing OMT between 1 April 2018 and 27 January 2023. Measurements: OMT‐related adverse events, post‐OMT diagnosis of SAI, and OMT comparison to CST. Results: OMT was performed in 114 patients (81, 71% women) at a median age of 48 (interquartile range 37–58). The pretest probability for SAI was low in 52 (46%) patients, moderate in 48 (42%) patients and high in 14 (12%) patients. Adverse events were reported in 7 (6.1%) patients and were mild except for one hospitalization. No baseline or OMT‐related factors were associated with the development of adverse events. Prevalence of the OMT‐based SAI diagnosis was 26 (23%) and 47 (46%) using 11‐deoxycortisol cutoff <7 and <10 mcg/dL, respectively. Higher pretest probability was associated with the OMT‐based diagnosis of SAI. Post‐OMT 11‐deoxycortisol cutoff of 10 mcg/dL was used most to diagnose SAI. Compared to the OMT‐based diagnosis of SAI (11‐deoxycortisol cutoff of 10 mcg/dL), the specificity of CST was 100%, but the sensitivity was only 52%. Conclusions: OMT was well tolerated and used in patients with low and moderate pretest probability for SAI. CST can erroneously exclude patients with SAI. Thus, OMT should be considered in selected patients with normal CST. [ABSTRACT FROM AUTHOR]

The frictional properties of the coarse aggregate used in asphalt concrete are a major contributor to the friction of the surface mixes. Selecting an aggregate that is not only polish and crush resistant to withstand the mechanical degradation and grinding under traffic loading, but also has a low friction loss rate and reasonable friction life is vital. A laboratory aggregate test program was carried out to evaluate the polishing/friction and crushing performance of 25 different aggregate sources from different locations. Two widely used friction test methods, i.e., British pendulum testing (BPT) and dynamic friction testing (DFT) in conjunction with the three-wheel polishing testing (TWPD) and the aggregate crushing value test (ACV) were used to quantify the polishing and crushing resistance of aggregates, respectively. Several frictional and crushing test parameters were introduced, analyzed, and finally, a correlation analysis was performed to relate different aggregate friction, polishing, and crushing test parameters. All three tests showed low variability when replicate samples were compared. A strong correlation (R value of 0.92) was found between the friction loss rate and the ACV test parameters and a linear correlation with R2 of greater than 0.80 was observed between the final friction life of the aggregate and the BPT test parameters. The ACV and TWPD/BPT tests can be potentially considered as an alternative test for friction evaluation of the coarse aggregates in case the DFT device is not available, with some loss in the sensitivity in characterizing marginal materials. [ABSTRACT FROM AUTHOR]

Nighttime object detection is challenging due to dim, uneven lighting. The IIHS research conducted in 2022 shows that pedestrian anti-collision systems are less effective at night. Common solutions utilize costly sensors, such as thermal imaging and LiDAR, aiming for highly accurate detection. Conversely, this study employs a low-cost 2D image approach to address the problem by drawing inspiration from biological dark adaptation mechanisms, simulating functions like pupils and photoreceptor cells. Instead of relying on extensive machine learning with day-to-night image conversions, it focuses on image fusion and gamma correction to train deep neural networks for dark adaptation. This research also involves creating a simulated environment ranging from 0 lux to high brightness, testing the limits of object detection, and offering a high dynamic range testing method. Results indicate that the dark adaptation model developed in this study improves the mean average precision (mAP) by 1.5−6% compared to traditional models. Our model is capable of functioning in both twilight and night, showcasing academic novelty. Future developments could include using virtual light in specific image areas or integrating with smart car lighting to enhance detection accuracy, thereby improving safety for pedestrians and drivers. [ABSTRACT FROM AUTHOR]

This study comprehensively describes the viscoelastic behavior of high-elasticity modified asphalt mixtures under varying strain conditions. The commonly used sigmoidal model, which relies on a single parameter (dynamic modulus) to depict viscoelastic behavior, has limitations. In this research, by utilizing the dynamic modulus master curve and the Kramers–Kronig relationship, master curve models developed for the phase angle, storage modulus, and loss modulus enable a more comprehensive understanding of the materials' viscoelastic response functions. Dynamic modulus tests were conducted on the high-elasticity modified asphalt mixtures using the simple performance tester (SPT) at various temperatures (5°C, 15°C, 25°C, 40°C, and 55°C) and frequencies (0.1, 0.5, 1, 5, 10, 20, and 25 Hz). The results indicate that the master curves of the phase angle, storage modulus, and loss modulus, established using the dynamic modulus master curve and Kramers–Kronig relationship, are well-fitted, demonstrating that the method feasibly can be used to draw the master curves for each viscoelastic parameter. Additionally, mathematical models based on the Kramers–Kronig relationship were developed to explain the correlations among parameters under dynamic loading conditions, and the accuracy of the master curve models for various parameters was validated. This deeper insight into material responses under varying loading conditions and temperatures can help researchers better model and predict the mechanical performance of pavements. [ABSTRACT FROM AUTHOR]

The investigation of inhomogeneous materials under dynamic conditions presents several challenges, particularly with regard to testing the dynamic properties of concrete, which requires the use of a large-scale split-Hopkinson pressure bar (SHPB). The present study aims to address these challenges by designing and calibrating a 155 mm diameter SHPB. The design and construction of the apparatus are described, and its data processing, including wave pulse dispersion correction, is assessed to ensure accurate representation of stress and deformation conditions. The apparatus is validated through experiments on brittle (confined concrete) and ductile (copper) specimens. The results demonstrate the ability of SHPB to characterize the dynamic properties of large-scale specimens and to correct dispersed signals in the bar, allowing for the accurate determination of specimen surface pulses. Validity of the results is confirmed through one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) wave analyses. Therefore, the 155 mm diameter SHPB setup has shown excellent performance in deriving the dynamic properties of large-diameter specimens. This study provides evidence to support the conclusion that the utilization of a 155 mm SHPB setup enables the experimental assessment of dynamic properties in large-diameter specimens. This conclusion is directly supported by the analysis of test data obtained from confined concrete samples and copper materials. [ABSTRACT FROM AUTHOR]

The mechanical behaviors of shales with transversely isotropic characteristics under dynamic loading have great significance for structural instability in geotechnical engineering. To understand the effect of transverse isotropy on the deformability and tensile strength of shales subjected to dynamic loading, a group of impact Brazilian tests were carried out on shale specimens via a split Hopkinson pressure bar (SHPB) testing system. High-speed digital image correlation technology was applied to monitor the fracture process. The experimental results demonstrate that the failure strength has considerable anisotropy as the bedding angle of the embedded layers changes. Moreover, the tensile strength of shales with vertical bedding is usually higher than that of shales with parallel bedding. The observed failure mode is mainly the interaction between tensile and/or shear fractures, and with increasing loading rate, layer-activated fractures tend to occur. Furthermore, five typical failure patterns of transversely isotropic shales characterized by different mechanisms under dynamic Brazilian testing were found. The shales were sensitive to the strain rate when the deformation and fracture response under dynamic loading were assessed. In addition, the modified Nova‒Zaninetti criterion that considers the strain rate effect was proposed according to the Brazilian splitting data and dynamic coordinate system. The established criterion not only properly represents the law of dynamic strength but also provides a new understanding of the effect of strain rate on strength. It has proven to be effective for predicting the dynamic strength characteristics of shales. Highlights: With increasing loading rate, the layer-activated fractures tend to occur. Under high strain rates, cracks generally develop along diversified directions inclined to the bedding planes. Five typical failure patterns of transversely isotropic shales under dynamic Brazilian splitting were concluded. The modified Nova‒Zaninetti criterion considering strain rate effect was proposed. [ABSTRACT FROM AUTHOR]

To meet the demand for the accurate measurements of the dynamic pressure of a shock wave, a composite dynamic pressure sensor design method is proposed based on the formation mechanism, propagation characteristics, special testing environment of the dynamic pressure, and Pitot tube structure. The dynamic pressure of the shock wave is evaluated by the total pressure and static pressure units installed in the composite sensor. FLUENT simulation software was used to analyze the aerodynamic characteristics of the dynamic pressure sensor, and parameters such as the structural size and inlet position of the sensor were determined. In response to the special experimental environment of the shock wave, the requirements for the dynamic pressure measurements under damage conditions were analyzed, and a dynamic pressure testing system was established. Dynamic pressure tests with four 2,4,6-trinitrotoluene [C7H5(NO2)3] equivalents of 1, 2, 15, and 20 kg were carried out. The experimental results show that the proposed sensor design method can accurately and effectively measure the dynamic pressure signal, and the dynamic pressure gain multiple decreases with an increase in the proportional distance. This provides an effective testing method for evaluating the dynamic pressure damage effect of ammunition systems. [ABSTRACT FROM AUTHOR]

Industrial robots are important components in the production and manufacturing industry. As a core component of the industrial robot, the industrial robot reducer plays a crucial role in the performance of the entire industrial robot. The error analysis and accuracy traceability of the industrial robot reducer testing instrument are of great significance in improving the quality of the precision reducer. Therefore, it is essential to calibrate the dynamic torsional moment measurement error of the instrument. The features of the dynamic torsional moment measurement error are analyzed in this paper. Based on these features, a new dynamic torsional moment measurement error calibration method is proposed based on the Bisquare curve fitting–improved Bayes particle swarm optimization–nonlinear echo state network (BCF–IBPSO–NESN) algorithm. The proposed method focuses on calibrating the dynamic torsional moment measurement error of the industrial robot reducers in real time. The experimental results show that the dynamic torsional moment measurement error of the input side torsional moment measurement module and the output side torsional moment measurement module can be reduced to ±0.05 Nm and ±1 Nm, respectively. The contribution of this paper is that the method calibrates the dynamic torsional moment measurement error. It supplies a guideline for calibrating the dynamic torsional moment measurement error of the instrument under any load. [ABSTRACT FROM AUTHOR]

The study investigates the influence of geonet and non-woven geotextile reinforcement on the strength performance of municipal solid waste (MSW fines). A set of unconsolidated undrained static and dynamic triaxial tests was conducted on the reinforced MSW fines samples by a varying number of reinforcement layers (0, 1, 2 and 3) to investigate the stress-strain and strength behaviour of the composite material. The MSW fines (particle size < 4.75 mm) inherently exhibit limited mechanical strength and required the use of additional ground improvement procedures to make them suitable for practical field applications. Although laboratory tests have shown improvements in the static strength of the investigated MSW fines when reinforced, due to the lack of any observed improvements in its dynamic strength characteristics, concerns continue regarding the viability of using this composite material in high seismic zones. [ABSTRACT FROM AUTHOR]