Average Acceleration Research Articles

A high-latitude coronal mass ejection observed by a constellation of coronagraphs: Solar Orbiter/Metis, STEREO-A/COR2, and SOHO/LASCO

Context. A few days before the first perihelion of the Solar Orbiter nominal mission, which occurred on 2022 March 26, the Metis coronagraph on board Solar Orbiter detected a coronal mass ejection (CME) that was moving away from the far side of the Sun (with respect to Solar Orbiter) at high northern latitudes. The eruption was also seen by other spacecraft, in particular, by STEREO-A, which was in quadrature configuration with Solar Orbiter. Aims. We analyse the different views of the CME by a constellation of spacecraft with the purpose to determine the speed and acceleration of the CME, and to identify the source region of the CME. Methods. Considering the positions of various spacecraft on 2022 March 22, this CME happened to be within the field of view of STEREO-A/SECCHI, and it was visible over the limb from SOHO/LASCO. We present the results of the 3D reconstruction of the CME based on the graduated cylindrical shell model and of the identification of the possible origin of the CME using extreme-ultraviolet (EUV) observations by Solar Orbiter/EUI, STEREO-A/EUVI, and SDO/AIA. The observations in EUV are compared with the coronal magnetic structure obtained by the potential field source surface method. Results. The 3D reconstruction of the CME derives a central latitude of 29° N, a Stonyhurst longitude of −125°, and an average radial speed at the apex of 322 ± 33 km s−1 between 4 and 13 R⊙, which is probably not high enough to generate a shock wave. The estimated average acceleration of the CME is 16 ± 11 m s−2 in the same range of distances from the Sun. This CME may be associated with the disappearance of a coronal cloud prominence, which is seen in the EUV by STEREO-A/EUVI and SDO/AIA, and is also associated with rapidly evolving emerging magnetic flux.

Properties of Binary Systems in a One-dimensional Approximation

Evolutionary calculations for stars in close binary systems are in high demand to obtain better constraints on gravitational-wave source progenitors, understand transient events from stellar interactions, and more. Modern one-dimensional (1D) stellar codes make use of the Roche lobe radius R L concept in order to treat stars in binary systems. If the stellar companion is approaching its R L, mass transfer treatment is initiated. However, the effective acceleration also affects the evolution of a star in a close binary system. This is different from the gravity inside a single star, whether that single star is rotating or not. Here, we present numerically obtained tables of properties of stars in a binary system as a function of the effective potential: volume-equivalent radii of the equipotential surfaces, effective accelerations and the inverse effective accelerations averaged over the same equipotential surfaces, and the properties of the L 1-plane cross sections. The tables are obtained for binaries where the ratios of the primary star mass to the companion star mass are from 10−6 to 105 and include equipotential surfaces up to the star’s outer Lagrangian point. We describe the numerical methods used to obtain these quantities and report how we verified the numerical results. We also describe and verify the method to obtain the effective acceleration for nonpoint mass distributions. We supply a sample code showing how to use our tables to get the average effective accelerations in 1D stellar codes.

Physical activity, sedentary behavior and pancreatitis risk: Mendelian randomization study.

Although observational studies have shown that physical activity is a protective factor for acute pancreatitis, the causal associations between PA/ sedentary behavior and acute pancreatitis (AP) and chronic pancreatitis (CP) remain unclear. We used Mendelian randomization as a strategy to assess the causalities between exposures and outcomes by simulating randomized experiments with genetic variation. The collected genetic variants data of physical activity were from UK Biobank, the data on sedentary behavior were also from UK Biobank, and both of them could be found in the GWAS catalog, and the data on AP and CP were from FinnGen. There were three physical activity related activity patterns (moderate to vigorous physical activity [MVPA], accelerometer-based physical activity with average acceleration, [AccAve] and accelerometer-based physical activity with accelerations >425 milli-gravities, [Acc425]) and three sedentary behavior-related lifestyle patterns (Leisure screen time [LST], Sedentary commuting, Sedentary behavior at work). We used inverse variance weighted (IVW), weighted median and MR-Egger for the analysis of Mendelian randomization, followed by sensitivity tests with the Cochran Q test, MR-Egger intercepts analysis and MR-PRESSO. A causal relationship was found between LST and acute pancreatitis based on IVW analysis (odds ratios [OR] = 1.38, corresponding 95% confidence intervals [CI] = 1.16-1.64, p = 0.0002) and there were no causal relationships between physical activity/sedentary behavior and chronic pancreatitis. Sensitivity analysis showed no pleiotropy and heterogeneity of the results. Results show that reducing LST contributes to the prevention of acute pancreatitis, thereby reducing the health burden associated with it.

A polynomial extrapolation-based wavelet-Galerkin method for dynamic response reconstruction

In this work we present a single scale wavelet-Galerkin method (WGM) for obtaining the linear dynamic response of single degree of freedom (SDOF) and multi-degree of freedom (MDOF) systems, the equation of motion is discretized using a polynomial extrapolation-based time stepping scheme. The aim of the study is to investigate the accuracy of the dynamic response resulting from the application of the proposed method and to explore the Daubechies wavelet types that can be used for unconditional stability. In our work we solve only for the scaling function coefficients of the displacement response, the scaling function coefficients of the velocity and the acceleration responses are obtained from the solved scaling function coefficients of the displacement function and the pertaining connection coefficients. The classical central differences method (CCDM) is used to generate consistent values of the velocity and the acceleration response to replace the distorted ones at the edges of the time interval. Stability analysis shows that the method using D6 wavelets is unconditionally stable for the practical range of the product of the time step and the frequency of vibration. An application of a SDOF system with initial conditions shows that for D6 wavelets the calculated responses at an adequate approximation level correspond well with those obtained using Newmark’s average acceleration method (AAM). The method is also applied to a MDOF system without performing a modal analysis, the resulting dynamic response is found to be accurate enough to be compared to that of the mode superposition method used by the STAAD pro program.

Moving Load Analysis of Laminated Porous Micro Beams Resting on Elastic Foundation

This research highlights dynamic displacements of laminated porous micro beams resting on elastic foundation under moving load. In the constituted equation of laminated micro scaled beam, the modified coupled stress theory is used in order to determine the size effect. Each layer is considered as identical and porosity distribution and assumed as uniform. Lagrange technique is applied in achieving governing equations, and Ritz method within algebraic polynomials is used for solution. For dynamic solution steps, Newmark average acceleration method is used within time domain. Influences of porosity coefficients, length scale parameter, foundation parameter, order of laminas, fiber orientation angles on dynamically deflections of laminated micro beam are investigated.

A risk-targeted approach for the seismic design of bridge piers

Designing a structure to resist earthquakes by targeting an explicit failure risk has been a key research topic over the past two decades. In this article, a risk-targeted design approach is developed for circular reinforced concrete bridge piers, based on a probabilistic optimization procedure aimed at minimising the design resisting moment at the pier base. In order to reduce the computational effort, a surrogate model is developed to describe the influence of two key design parameter (i.e., the pier diameter and the longitudinal reinforcement ratio) on the structural behaviour and performance. The proposed approach is applied in a case study for Italy for target mean annual frequencies of failure selected according to European codes using a probabilistic seismic hazard assessment for average spectral acceleration across a wide range of structural periods. The variation in the design parameters across Italy is considerable because of the large variation in seismic hazard. It is found that in areas of low seismic hazard the level of seismic design required is near the minimum allowed by Eurocode 8 in terms of reinforcement ratio. In areas of the highest seismic hazard much higher reinforcement ratios and pier diameters are required to meet the risk targets. If both pier diameter and longitudinal reinforcement ratios are considered as design parameters then the optimisation procedure may mean adjacent sites have significant different pairs of these parameters as the target can be reached in multiple ways. This problem can be solved by fixing one parameter and optimising the other.

Risky Driver Identification Using Beta Regression Based on Naturalistic Driving Data

Naturalistic driving data are widely used to investigate factors related to road safety. Crashes and near-crashes can be regarded as the critical events on the road. The existing studies typically modeled crash and near-crash events at the trip level. However, individual drivers may have different risk levels, and other factors such as distraction can also play a role. This study uses variables automatically derived from naturalistic driving data. Driver distraction is detected from videos using facial landmarks. Based on the collected variables, a beta regression model is developed to identify the significant variables affecting drivers’ risk levels. It is found that the average acceleration rate, number of hard accelerations, driver distraction, and age are significant variables. The findings from this study can be used to identify risky drivers and improve the design of automated vehicles by eliminating human errors and risky driving patterns. Moreover, advanced driver assistance systems (ADAS) can be promoted to alert drivers to risky driving behaviors. The proposed model is also easy to implement in real driving conditions as most of the variables can be extracted automatically. Relevant agencies can also use the model to identify risky drivers and provide proactive customized education programs.

Linearly Implicit Algorithm with Embedded Newton Iteration of Velocity and its Application in Nonlinear Dynamic Analysis of Structures

With the application of energy dissipation and damping techniques such as viscous dampers and viscoelastic dampers in seismic engineering, dynamic equilibrium equations of overall structures involve nonlinear damping force. Therefore, numerical integration methods with explicit velocity expressions are more favorable. Based on the average acceleration method, a novel linearly implicit algorithm with explicit expression of velocity is proposed in which once Newton iteration is embedded. The stability of the proposed algorithm in solving equations of motion containing nonlinear restoring force and nonlinear damping force is analyzed using the root locus method. The nonlinear stability of the proposed algorithm is also examined using a single-degree-of-freedom shear-type structure. The dynamic response analysis of a three-storey shear structure model equipped with viscous dampers, a three-storey shear structure equipped with metal dampers, and an eight-storey planar frame structure, are carried to investigate the accuracy and stability of the proposed method with respect to the Chang method and the CR method. The results show that the proposed algorithm exhibits higher accuracy and finer stability for nonlinear dynamic problems.

Physical activity and the risk of periodontitis: an instrumental variable study

ObjectivesObservational studies suggested an inverse association between physical activity and periodontitis. However, observational studies might be subject to unobserved confounding and reverse causation bias. We conducted an instrumental variable study to strengthen the evidence on the relationship between physical activity and periodontitis.Materials and methodsWe used genetic variants associated with self-reported and accelerometer-assessed physical activity in 377,234 and 91,084 UK Biobank participants, respectively, as instruments. For these instruments, genetic associations with periodontitis were obtained from 17,353 cases and 28,210 controls in the GeneLifestyle Interactions in Dental Endpoints consortium.ResultsWe found no evidence for effects of self-reported moderate-to-vigorous physical activity, self-reported vigorous physical activity, accelerometry “average accelerations,” and “fraction of accelerations > 425 milli-gravities” on periodontitis. For example, the odds ratio for self-reported moderate-to-vigorous physical activity was 1.07 (95% credible interval: 0.87; 1.34) in Causal Analysis using Summary Effect Estimates. We conducted sensitivity analyses to rule out weak instrument bias and correlated horizontal pleiotropy.ConclusionsThe study does not support an effect of physical activity on the risk of periodontitis.Clinical relevanceThis study provides little evidence that recommending physical activity would help prevent periodontitis.

Оптимизация конструктивных параметров пневмогидравлического седельно-сцепного устройства лесовозного автопоезда

In this study, the benefits of logging transportation under modern conditions by semitrailer hauling rig are examined, which consists of a truck tractor connected to a semitrailer. Furthermore, an analysis is made of the operational implications of using log road trains in insufficiently arranged road conditions. The article describes the potential scientific directions that can optimize the efficiency of semitrailer trucks. An improved construction of a regenerative fifth-wheel coupling device is proposed. It provides better reliability, reduces fuel consumption for log trucks, and gives better working conditions for drivers, along with reduced dynamic loads between the links of the units that occur during the movement in unsteady modes. The research methodology includes the application of the mathematical framework of multifactorial optimization. The specified analytical formulas are derived to determine the performance efficiency of the regenerative fifth-wheel coupling. It is revealed the connections between the hydraulic cylinder piston stroke values of the regenerative fifth-wheel coupling device, the weight of the loaded semitrailer, the vehicle acceleration during speeding up and braking, and the modifications of the performance indicators of the latching mechanism. The optimal value of the stroke of the pistons of the hydraulic cylinder is determined, which is 200 mm. It provides a power recovery of 6.5 kW and better longitudinal acceleration of the semitrailer at 0.72 m/s2. Moreover, it is found that the change in acceleration during the increase in velocity and braking from 1 to 3 m/s2 gives the change in recuperated power from 2.2 to 6.8 m/s2. At the same time, the average longitudinal acceleration of the semitrailer varies from 0.27 to 0.75 m/s2. Changing the load of the semitrailer from 5 to 25 tons allows increasing the recuperated power from 1.6 to 7.9 kW and reducing the longitudinal acceleration of the semitrailer from 2.8 to 0.53 m/s2. The influence graphs and optimization cartograms present the diameter and hydraulic cylinder piston stroke values of the regenerative fifth-wheel coupling device on the regenerated power and longitudinal acceleration of the semitrailer. According to the optimization cartograms, the average regenerative power is determined using a graph-analytical method. It is equal to 6.5 kW with the diameter of a regenerative hydraulic cylinder of 110 mm and a hydraulic cylinder piston stroke of 200 mm. For citation: Posmetyev V.I., Nikonov V.O., Manukovskii A.Yu., Posmetyev V.V., Avdyuhin A.V. Optimization of Structural Parameters by Improvement of Pneumohydraulic FifthWheel Coupling Device at Semitrailer Hauling Rig. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 3, pp. 126–139. (In Russ.). https://doi.org/10.37482/0536-1036-2023-3-126-139

Accelerometer-Assessed Physical Activity in People with Type 2 Diabetes: Accounting for Sleep when Determining Associations with Markers of Health

High physical activity levels during wake are beneficial for health, while high movement levels during sleep are detrimental to health. Our aim was to compare the associations of accelerometer-assessed physical activity and sleep disruption with adiposity and fitness using standardized and individualized wake and sleep windows. People (N = 609) with type 2 diabetes wore an accelerometer for up to 8 days. Waist circumference, body fat percentage, Short Physical Performance Battery (SPPB) test score, sit-to-stands, and resting heart rate were assessed. Physical activity was assessed via the average acceleration and intensity distribution (intensity gradient) over standardized (most active 16 continuous hours (M16h)) and individualized wake windows. Sleep disruption was assessed via the average acceleration over standardized (least active 8 continuous hours (L8h)) and individualized sleep windows. Average acceleration and intensity distribution during the wake window were beneficially associated with adiposity and fitness, while average acceleration during the sleep window was detrimentally associated with adiposity and fitness. Point estimates for the associations were slightly stronger for the standardized than for individualized wake/sleep windows. In conclusion, standardized wake and sleep windows may have stronger associations with health due to capturing variations in sleep durations across individuals, while individualized windows represent a purer measure of wake/sleep behaviors.

The need for eco-driving technologies in urban public transport

This article discusses the challenges facing public transport in Ukraine in terms of reducing fuel consumption and emissions. The absence or insufficient development of means and methods for monitoring driver behaviour, as well as high staff turnover, create significant difficulties in controlling drivers and vehicles. A conducted study in Lutsk, the administrative center of the Volyn region, analyzed the driving behavior of passenger buses in the city. Results showed that typical driving modes include idling (40%), acceleration (18%), driving at a constant speed (29%), and braking (13%). The study also revealed average accelerations and decelerations, and these results do not meet the requirements of ecological driving. The correlation between driver behavior and these dynamic acceleration and braking characteristics has been established. Possible causes for this phenomenon are discussed in the study. The article proposes the introduction of modern solutions to solve these problems. These solutions are Eco-Driving Assistance Systems (EDAS) or integrated systems, such as FleetControl from TRIONA, which can help learning operating conditions and reduce fuel consumption and emissions. These programmes can also serve as effective monitoring tools for individual drivers and transport companies. This paper describes these applications and reviews the research related to their use and development. In addition, the article highlights the importance of training drivers in eco-driving as a cost-effective method of improving fuel efficiency in transport companies. The paper concludes by emphasising the need for further research to fully understand the complexities of public transport in Ukraine and the potential benefits of introducing innovative technologies for a more sustainable and efficient future for the industry.

Stochastic Approach for 2D Superficial Seismic Amplification Based on Quad4M; City of L’Aquila (Italy) Test Case

The values of the physical–mechanical properties of any soil are affected by uncertainties both due to experimental measurements and the impossibility of knowing them, in detail, at every point of the spatial domain. Accordingly, this work focuses on uncertainty in shear wave velocity (Vs) and its impact on the seismic response. The Monte Carlo method, based on pseudo-random number generation, was selected. To understand which random distributions could identify the site’s real conditions, the Fourier spectrum frequencies were calculated for each realization and were compared with the predominant natural site frequency. The experimental range data were used to calculate the spectral average acceleration and the horizontal amplification factors. The simulations were performed and interpreted by a modified version of VisualQ4M software based on 2D Quad4M, including the generation of pseudo-random numbers and pre- and post-data processing. A site at a small scale, in the territory of the city of L’Aquila (Italy), was selected as the test case. This paper demonstrates, from a numerical point of view, that both a simple local topographic modification due to excavation and the uncertainties of the numerical values, even of the shear wave velocity alone, can have an important impact on the local seismic amplification.

Capurability analysis for arbitrarily high-speed maneuvering targets

The capturability of an arbitrarily maneuvering target featuring speed superiority over an interceptor is analyzed for Augmented Pure Proportional Navigation (APPN) and Retro-Augmented Proportional Navigation (RAPN) guidance. This paper focuses on intercepting arbitrary maneuvers to study more general interception problems. A comparative analysis of the capture region between head-on interception related to APPN and head-pursuit interception related to RAPN is proposed. The results indicate that RAPN performs better than APPN in capturability. It is concluded that increasing the target velocity, which increases the velocity ratio, significantly weakens the capturability of the interceptor, and the average acceleration and relative distance affect the location of the capture region but not its size. The analysis is based on prior knowledge of the target maneuver, which inevitably leads to deviations from actual maneuvers in practical engagement, so a deviation analysis is implemented. The effective capture region shrinks as the absolute value of acceleration deviation increases, and the RAPN has a better deviation fault tolerance compared with the APPN. The results reveal that a larger relative distance can weaken the deviation fault tolerance, and the target velocity has opposite effects on head-on and head-pursuit interception.

Smartphone Technology to Remotely Measure Postural Sway during Double- and Single-Leg Squats in Adults with Femoroacetabular Impingement and Those with No Hip Pain.

The COVID-19 pandemic has accelerated the demand for utilising telehealth as a major mode of healthcare delivery, with increasing interest in the use of tele-platforms for remote patient assessment. In this context, the use of smartphone technology to measure squat performance in people with and without femoroacetabular impingement (FAI) syndrome has not been reported yet. We developed a novel smartphone application, the TelePhysio app, which allows the clinician to remotely connect to the patient's device and measure their squat performance in real time using the smartphone inertial sensors. The aim of this study was to investigate the association and test-retest reliability of the TelePhysio app in measuring postural sway performance during a double-leg (DLS) and single-leg (SLS) squat task. In addition, the study investigated the ability of TelePhysio to detect differences in DLS and SLS performance between people with FAI and without hip pain. A total of 30 healthy (nfemales = 12) young adults and 10 adults (nfemales = 2) with diagnosed FAI syndrome participated in the study. Healthy participants performed DLS and SLS on force plates in our laboratory, and remotely in their homes using the TelePhysio smartphone application. Sway measurements were compared using the centre of pressure (CoP) and smartphone inertial sensor data. A total of 10 participants with FAI (nfemales = 2) performed the squat assessments remotely. Four sway measurements in each axis (x, y, and z) were computed from the TelePhysio inertial sensors: (1) average acceleration magnitude from the mean (aam), (2) root-mean-square acceleration (rms), (3) range acceleration (r), and (4) approximate entropy (apen), with lower values indicating that the movement is more regular, repetitive, and predictable. Differences in TelePhysio squat sway data were compared between DLS and SLS, and between healthy and FAI adults, using analysis of variance with significance set at 0.05. The TelePhysio aam measurements on the x- and y-axes had significant large correlations with the CoP measurements (r = 0.56 and r = 0.71, respectively). The TelePhysio aam measurements demonstrated moderate to substantial between-session reliability values of 0.73 (95% CI 0.62-0.81), 0.85 (95% CI 0.79-0.91), and 0.73 (95% CI 0.62-0.82) for aamx, aamy, and aamz, respectively. The DLS of the FAI participants showed significantly lower aam and apen values in the medio-lateral direction compared to the healthy DLS, healthy SLS, and FAI SLS groups (aam = 0.13, 0.19, 0.29, and 0.29, respectively; and apen = 0.33, 0.45, 0.52, and 0.48, respectively). In the anterior-posterior direction, healthy DLS showed significantly greater aam values compared to the healthy SLS, FAI DLS, and FAI SLS groups (1.26, 0.61, 0.68, and 0.35, respectively). The TelePhysio app is a valid and reliable method of measuring postural control during DLS and SLS tasks. The application is capable of distinguishing performance levels between DLS and SLS tasks, and between healthy and FAI young adults. The DLS task is sufficient to distinguish the level of performance between healthy and FAI adults. This study validates the use of smartphone technology as a tele-assessment clinical tool for remote squat assessment.

Construction of Collision Equivalent Scaled Model for Locomotive Using Multi-Parameter Nondimensional Method

At present, the research on crashworthiness of locomotive mainly adopts the method of theoretical analysis, numerical simulation and component test, it is too expensive and less repeatable to carry out vehicle crash tests. Therefore, a method to construct the collision equivalent scaled model (SM) for locomotive based on multi-parameter nondimensional is presented in this paper. Firstly, an equivalent method of structural dynamic responses was proposed. The extraction process and analysis method of dynamic responses for thin plate structures widely existing in locomotives were studied. Then, according to the structural characteristics of the locomotive, the partition equivalent design was carried out, and a dimensionless analysis model of impact dynamic responses for SM was established. Finally, the SM crash test was carried out to verify the effectiveness of collision equivalent SM established, it was found that the SM has high reliability, it can achieve equivalence with the locomotive for energy absorption, average impact force, average acceleration of cab and center of gravity of vehicle body. Carrying out the SM crash test can study the reasonable configuration of energy absorption parameters for locomotives and obtain the impact dynamic responses of locomotives under different configurations of energy absorption parameters.

A 24-h activity profile and adiposity among children and adolescents: Does the difference between school and weekend days matter?

Twenty-four-hour movement behaviours are gaining attention in the research community. However, no study has addressed how 24-h activity profiles vary between structured and less structured days and whether an unfavourable activity profile is associated with childhood obesity. We aimed to analyse differences between school day and weekend day 24-h activity profiles and their associations with adiposity indicators among children and adolescents. Participants were 382 children and 338 adolescents who wore wrist accelerometers for 24 hours a day for seven consecutive days. The 24-h activity profile expressed by the average acceleration (AvAcc) and intensity gradient (IG) were estimated from multi-day raw accelerometer data. Adiposity indicators included body mass index (BMI) z-score, fat mass percentage (FM%), fat mass index (FMI), and visceral adipose tissue (VAT). Multiple linear regression of activity profile metrics and adiposity indicators was performed separately for school and weekend days. Weekend days AvAcc and IG were lower compared to school days in both age groups (p <0.001 for all). Specifically, AvAcc was lower by 9.4% and 11.3% in children and adolescents, respectively. IG on weekend days was lower (more negative) by 3.4% in children and 3.1% in adolescents. Among children, on school days AvAcc and IG were negatively associated with FM%, FMI, and VAT, whilst on weekend days AvAcc was positively associated with BMI z-score, FMI, and VAT (p < 0.05 for all). Among adolescents, negative associations were found between weekend day AvAcc and IG and FM% and FMI (p < 0.05 for all), respectively. This study confirms the importance of 24-h activity profile as a potentially protective factor against excess adiposity. The variability of movement behaviours during structured and less structured days should be considered when optimizing the 24-h movement behaviours to prevent childhood obesity.

Оптимизация конструктивных параметров рекуперативного сцепного устройства, установленного в лесовозном автомобиле с прицепом

This article solves the problem of increasing the efficiency of the functioning of logging road trains in conditions of insufficiently equipped logging roads. Experience in the operation of road trains on such logging roads shows that on these roads the transport and operational qualities of logging road trains are low. The relevance of the scientific direction, aimed at achieving the fuel efficiency of logging road trains and thus increasing the efficiency and competitiveness of logging enterprises, is substantiated. An analysis of the work of foreign scientists is presented, which made it possible to identify significant factors that largely determine the efficiency of the process of hauling timber by timber road trains. A promising design of the coupling device is proposed, which allows converting and usefully using the kinetic energy of the mass of the trailer with timber, which occurs during the movement of a road train along insufficiently equipped logging roads in unsteady and transient traffic modes. The study was based on mathematical and simulation modeling, numerical methods, as well as modern methods for obtaining and processing information with computer support. A mathematical model and a computer program for the movement of a timber road train under changing road conditions have been developed. Computer simulation made it possible to carry out a preliminary assessment of the performance of the proposed pneumohydraulic coupling device with recuperative and damper mechanisms by identifying and analyzing dependencies characterizing the change in the studied performance indicators on the driving conditions of the road train and the design parameters of the device. It has been established that the coupling device during the movement of a logging road train in difficult road conditions at a speed of 30 km/h makes it possible to recuperate up to 7 kW, while the value of the longitudinal acceleration of the trailer link relative to the logging vehicle does not exceed 0.83 m/s2. It is determined that the value of the optimal diameter of the recuperative hydraulic cylinder is 80 ... 100 mm, and the optimal piston stroke is 83 ... 100 mm. In this case, the average power recuperated by the device will be at least 7 kW, and the average longitudinal acceleration of the trailer will be no more than 0.8 m/s2. It was found that the developed recuperation system remains effective in a wide range of roughness heights of 0.2 ... 0.4 m, providing a recuperated power of 2.3 ... 19.7 kW, respectively, with an acceptable average longitudinal acceleration of 0.3 ... 2.2 m/s2. The results obtained will be used as recommendations for designers to refine the proposed coupling device at the design stage.

Evaluation of typology‐specific fragility curves used for risk‐targeted seismic demand maps in regions of low seismicity: A German case‐study

AbstractInvestigations of risk targeted peak ground acceleration (PGA) maps for European countries typically adopt a single generic fragility curve definition. The aim of this study is to investigate the use of typology‐specific fragility curves in the derivation of risk‐targeted PGA maps in low seismicity regions. This study differs from previous works in that it derives expressions for the relationship between design PGA and the median collapse capacity for several different structural typologies designed according to European standards, namely, reinforced concrete (RC) moment‐resisting frames (MRFs), reinforced concrete wall and dual systems, and steel MRFs. The expressions were determined from the regression analysis of a database of fragility curve parameters collected from the literature. The influence of the different typology‐specific fragility functions on the derivation of risk‐targeted seismic maps in regions of low seismicity, using Germany as a case‐study, is discussed. The key findings of this study are as follows: the fragility curves derived using the database possess significant inherent lateral capacity; the consideration of this inherent lateral capacity implies the reduction of the regions where seismic design is compulsory; and that fragility curves adapted from fragility analyses from structures in the US may not be representative of European structures. Recommendations for the direction of future research include focusing primarily on improving the definition of the typology‐specific fragility curves; developing fragility curves for modern IMs such as average spectral acceleration; and investigating the use of typology‐specific curves in regions of high seismicity.

Upper-Limb Kinematic Behavior and Performance Fatigability of Elderly Participants Performing an Isometric Task: A Quasi-Experimental Study.

To understand the ULPSIT effects on upper-limb (UL) kinetics and performance fatigability in the elderly. Thirty-one (31) elderly participants (72.61 ± 5.23 years) performed an ULPSIT. The UL average acceleration (AA) and performance fatigability were measured using an inertial measurement unit (IMU) and time-to-task failure (TTF). The findings showed significant changes in AA in the X- and Z-axes (p < 0.05). AA differences in women started earlier in the baseline cutoff in the X-axis, and in men, started earlier between cutoffs in the Z-axis. TTF was positively related to AA in men until 60% TTF. ULPSIT produced changes in AA behavior, indicative of movement of the UL in the sagittal plane. AA behavior is sex related and suggests higher performance fatigability in women. Performance fatigability was positively related to AA only in men, where movement adjustments occurred in an early phase, though with increased activity time.