Additional Load Research Articles

Increased force and elastic energy storage are not the mechanisms that improve jump performance with accentuated eccentric loading during a constrained vertical jump.

Accentuated eccentric loading (AEL) involves higher load applied during the eccentric phase of a stretch-shortening cycle movement, followed by a sudden removal of load before the concentric phase. Previous studies suggest that AEL enhances human countermovement jump performance, however the mechanism is not fully understood. Here we explore whether isolating additional load during the countermovement is sufficient to increase ground reaction force, and hence elastic energy stored, at the start of the upward movement and whether this leads to increased jump height or power generation. We conducted a trunk-constrained vertical jump test on a custom-built device to isolate the effect of additional load while controlling for effects of squat depth, arm swing, and coordination. Twelve healthy, recreationally active adults (7 males, 5 females) performed maximal jumps without AEL, followed by randomised AEL conditions prescribed as a percentage of body mass (10%, 20%, and 30%), before repeating jumps without AEL. No significant changes in vertical ground reaction force at the turning point were observed. High load AEL conditions (20% and 30% body weight) led to slight reductions in jump height, primarily due to decreased hip joint and centre of mass work. AEL conditions did not alter peak or integrated activation levels of the knee extensor muscles. The constrained movement task used here, which excluded potential contributions of trunk motion, arm swing, rate of descent, squat depth, and point of load application, allows the conclusion that increased elastic energy return is not the primary mechanism for potentiating effects of AEL on jump performance.

Performance Evaluation of Foamed Concrete with Lightweight Aggregate: Strength, Shrinkage, and Thermal Conductivity.

Lightweight concrete offers numerous advantages for modular construction, including easier construction planning and logistics, and the ability to offset additional dead loads induced by double-wall and double-slab features. In a previous study, authors proposed incorporating lightweight aggregate into foamed concrete instead of adding extra foam to achieve lower density, resulting in lightweight concrete with an excellent strength-to-density ratio. This paper further investigated the performance aspects of foamed concrete with lightweight aggregate beyond mechanical strength. To evaluate the effect of aggregate type and foam content, three mix compositions were designed for the lightweight concrete. Specimens were prepared for experimental tests on thermal conductivity and drying shrinkage of lightweight concrete. Results showed that while both the increase in foam volume and the incorporation of lightweight aggregate led to higher drying shrinkage, they also contributed to improved insulating properties and reduced potential of cracking. Using typical multi-storey modular residential buildings in Hong Kong and three other Chinese cities as case studies, simulations were performed to assess potential savings in annual cooling and heating loads by employing the proposed lightweight concrete. These findings demonstrate the practical benefits of using foamed concrete with lightweight aggregate in modular construction and provide valuable insights for further optimization and implementation.

Investigation of H∞$$ {\mathcal{H}}_{\infty } $$‐Tuned Individual Pitch Control for Wind Turbines

ABSTRACTLarge wind turbines experience amplified asymmetrical loads at particular harmonics of the rotational frequency. Individual pitch control (IPC) has emerged as a potential controls solution to this problem. control, which facilitates robust, multivariable controller synthesis in the frequency domain, is a candidate approach to IPC design for several reasons. First, the objectives of asymmetrical load attenuation can be readily described in the frequency domain. Second, the IPC signals and loads in orthogonal directions are known to be coupled, which necessitates a multivariable controller approach. Third, synthesis is a method that can explicitly impose constraints on the robustness of the closed‐loop system. A downside of IPC is the significant increase in blade‐pitch travel incurred, which introduces additional loading on the blade‐pitch bearings over time. We investigate strategies to constrain the blade‐pitch travel in the controller tuning procedure. A comprehensive study is thus presented for a range of ‐synthesized IPCs to attenuate asymmetrical loads on large rotors at harmonics of the rotational frequency while reducing blade‐pitch travel. All developed controllers are validated and compared using a 25‐MW fixed‐bottom offshore wind turbine model via (a) linear analysis of the response of the closed‐loop system to input and output disturbances, (b) nonlinear analysis in terms of structural load power spectra and damage‐equivalent loads (DELs), and (c) the actuator duty cycle (ADC) of the blade‐pitch actuator.

Effects of mediolateral whole-body vibration during gait with additional cognitive load

Whole-body vibration (WBV) may increase musculoskeletal disorder risk among workers standing on vibrating surfaces for prolonged periods. Limited studies were conducted to comprehend WBV impact on individuals engaged in dynamic activities. This study explored the effects of different horizontal WBV frequencies on gait parameters, lower limb kinematics, and the cognitive response of healthy subjects. Forty participants walked at constant speed on a treadmill mounted on a horizontal shaker providing harmonic vibration with an amplitude of 1 m/s2 and frequencies 2–10 Hz, with inversely proportional amplitudes. A Psychomotor Vigilance Test measured reaction time while a motion capture system recorded walking kinematics. ANOVA results revealed no significant impact of vibration frequencies on the reaction time. At 2 Hz, alterations in gait spatiotemporal parameters were significant, with reduced stride length, stride time, step length, and stance time and increased step width and cadence. Similarly, gait variability measured by standard deviation and coefficient of variation significantly increased at 2 Hz compared to the other conditions. Comparably, kinematic time series analyzed through statistical parametric mapping showed significant adjustments in different portions of the gait cycle at 2 Hz, including increased hip abduction and flexion, greater knee flexion around the heel strike, and augmented ankle dorsiflexion. Participants exhibited gait kinematic variations, mainly at 2 Hz, where the associated mediolateral displacement was higher, as a plausible strategy to maintain stability and postural control during perturbed locomotion. These findings highlight individuals’ complex biomechanical adaptations in response to horizontal WBV, especially at lower frequencies, under dual-task conditions.

Monitoring Surface Deformations in a Fossil Landslide Zone and Identifying Potential Failure Mechanisms: A Case Study of Gümüşhane State Hospital.

The escalating occurrence of landslides has drawn increasing attention from the scientific community, primarily driven by a combination of natural phenomena such as unpredictable seismic events, intensified precipitation, and rapid snowmelt attributable to climate fluctuations, compounded by inadequacies in engineering practices during site selection. Within the scope of this investigation, contemporary geodetic techniques using the GNSS were employed to monitor structural and surface deformations in and around a hospital edifice situated within an ancient fossil landslide region. Additionally, inclinometer measurements facilitated the determination of slip circle parameters. A subsequent analysis integrated these datasets to scrutinize both the hospital structure and its surrounding slopes. In addition to the finite element method, four different limit equilibrium methods (Bishop, GLE-Morgenstern-Price, Spencer, and Janbu) were used in the evaluation of stability. Since the safety number determined in all analyses was <1, it was determined that the slope containing the hospital building was unstable. The movement has occurred again due to the additional load created by the hospital building built on the currently stable slope, the effect of surface and groundwater, and the improperly designed road route. As a result of geodetic monitoring, it was determined that the sliding speed on the surface was in the N-E direction and was approximately 3 cm, and this situation almost coincided with inclinometer measurements.

Efficiency of FRPU strengthening of a damaged masonry infill wall under in-plane cyclic shear loading and elevated temperatures

This paper presents results of in-plane shear tests carried out at the ZAG laboratory in Ljubljana (Slovenia) on a RC frame with masonry infill made of clay blocks (KEBE OrthoBlock). The frame was loaded with constant vertical loads at the top of the columns and then by gradually increasing horizontal cyclic loads at the top beam level. Acquired forces and measured displacements allowed capturing hysteretic behavior for determination of dissipation energy. In addition, two Digital Image Correlation (DIC) systems, Aramis and the CivEng Vision, were used to visualize the behavior of the tested specimens, with an emphasis on computing locally required information about the behavior of highly deformable interfaces. Three types of specimens were tested in-plane: the reference specimen in form of plain RC frame, the reference specimen with constructed masonry infill without any strengthening and the specimen, previously damaged and then strengthened on both sides using glass mesh bonded to the infill and the RC frame using flexible adhesive made of polyurethane matrix (Glass Fiber Reinforced PolyUrethane - GFRPU system). The strengthening process, allowed the specimen to withstand additional cyclic loads, reaching a maximum drift of 3.6 % without serious damage disqualifying the structure from further exploitation. The GFRPU strengthening system was found to be highly effective in preventing infill collapse of damaged masonry infill wall during in-plane loading. Additionally, the results of extended thermal analysis of PU are presented as polymers are, in general, a material, poorly resistant to heat. However, the analyzed PU manifested stable properties up to 200 degrees Celsius, which makes this material promising in civil engineering applications at elevated temperatures.

Boosting NIR Laser Marking Efficiency of a Transparent Epoxy Using a Layered Double Hydroxide.

Efficient near-infrared (NIR) laser marking on transparent polymers like polypropylene, epoxy, and polyethylene has posed a big challenge due to their lack of absorption in the NIR. Currently, inorganic additives are used to improve NIR laser marking efficiency, but they come with issues such as toxicity, high loading requirement, adverse effects on color/opaqueness, and the need for low laser head speeds. Herein, we report a new strategy of incorporating a food-grade, Mg2Al-CO3 LDH as a boosting coadditive alongside the commercial NIR laser marking additive (Iriotech 8815) in an epoxy system. Our findings demonstrate that the incorporation of Mg2Al-CO3 LDH can significantly increase both the darkness and contrast of marking even at high laser head speed (5000 mm/s), while minimizing surface damage. Notably, by replacing 95% of Iriotech 8815 with Mg2Al-CO3 LDH, an epoxy plate can exhibit high transparency, while producing dark, sharply defined markings with excellent readable QR code markings at high laser speeds. This result offers a promising solution for enhancing high-speed NIR laser marking on transparent polymers with additional advantages of lower toxicity and cost and with minimal optical interference from high additive loadings.

Evaluasi Rasio Kapasitas Plat Lantai Jembatan Pangwa Berdasarkan Mutu Beton Aktual

This article reviewed the effect of decreasing quality of concrete in the vehicle deck on Pangwa bridge located in Trienggadeng, Pidie Jaya district, Aceh Province. The bridge deck was planned to use concrete with a quality of 30 MPa, however in practice, it was estimated that only 18.8 MPa was achieved. Based on the actual concrete quality, this article reported a reanalysis of the bending and shear capacity ratio. Structural analysis was carried out using SAP2000 software referring to engineering design data. The stages include modeling the bridge as a space frame steel construction with a deck using reinforced concrete material, loads calculation, internal force analysis, and checking the structural capacity. Load calculations and load combinations refer to the standard Loading for Bridges (SNI 1725: 2016). The bridge deck was analyzed as a one way slabs using D16-150 reinforcement with steel grade fy = 320 MPa. The loads taken into structure analysis include: self weight, additional dead load, truck load, and wind load. Based on the loads on the bridge, it is estimated that the possible forces arising from certain conditions are calculated based on the ultimate load combination of Strength-I, Strength-II, Strength-III, Strength-IV and Strength-V according to the provisions of SNI 1725-2016. Based on the results of the structural analysis recapitulated from the value of the load combination, the maximum and minimum moments were 388.68 kN.m and -391.22 kN.m while the maximum shear force were 169.60 kN. The planned bending capacity was 396.303 kN.m (design) and was achieved at 365.568 kN.m (actual) or 7.75% less than the ultimate moment. The pons shear force arising on the bridge deck was Vu = 169.6 kN with pons shear capacity, ØVn = 874.895 kN in the design data and was achieved by 703.811 kN (actual). Based on the results of these calculations, it can be concluded that Pangwa bridge still meets the level of safety for the use as a vehicle traffic lane.

Cognitive issues of mobile map design and use

ABSTRACT Internet-connected mobile devices have changed how people access information. Like other information sources, maps have benefited from and been re-envisioned for mobile devices, and they are used in new contexts. However, these new contexts often generate additional cognitive load. We explored in depth two strategies designers could use to mitigate high cognitive loads associated with mobile map use: offloading cognition and reducing cognitive load by improved design to support the allocation of attention between the map and the environment. In reviewing these strategies, we considered their relevance to several mobile map use cases (navigation, individual and collaborative spatial decision making, information enrichment, and entertainment). Next, we identified recent progress in our understanding of how to measure cognitive load and map use context. Finally, we explored the wider implications of mobile maps for human behaviour and cognition. We identified two important cross-cutting research questions: 1) How can mobile maps be designed to reduce cognitive load by providing what is really needed by users to facilitate their cognitive processes?; 2) How can the intrinsic additional cognitive load created by the characteristics of mobile maps be managed and minimised by supporting the distribution of the user's attention between the map and environment?

Integrated Power and Thermal Management System for a Hybrid-Electric Aircraft: Integrated Modelling and Passive Cooling Analysis

Abstract Aircraft electrification introduces challenges in power and thermal management. In a hybrid-electric aircraft (HEA), the additional heat loads generated by the high-power electrical components in the propulsion system can negate the benefits of the HEA. Consequently, an integrated energy management system is required for the HEA to reject the additional heat loads while minimizing energy consumption. This paper presents the integrated modelling method for an integrated power and thermal management system (IPTMS) for HEA. With this method, a platform can be developed to assess the varying efficiencies of the components in the electrical propulsion system (EPS), and the performance of the thermal management system (TMS), such as passive cooling, during a flight mission. This makes it applicable to modular designs and optimizations of the IPTMS. A small/medium range (SMR) aircraft similar to ATR72 is studied. In this study, the EPS operates only during take-off and climb. Therefore, the platform assesses the heat and power loads of the IPTMS for a typical flight mission (take-off and climb) in this study. The performance of passive cooling is also analysed across this typical flight mission and under normal, hot-day, and cold-day conditions. It was found that passive cooling is sufficient under these three conditions, and the active temperature control is requried to ensure the components' temperatures are above the minimum temperatures. These findings imply the potential to minimize TMS weight and energy consumption, providing an insight for further research on IPTMS.

Does a Standardized Load Carriage Increase Spatiotemporal Gait Asymmetries in Police Recruits? A Population-based Study.

Although the effects of carrying loads on gait biomechanics have been well-documented, to date, little evidence has been provided whether such loads may impact spatial and temporal gait asymmetries under the different foot regions. Therefore, the main purpose of the study was to examine the effects of carrying a standardized police equipment on spatiotemporal gait parameters. In this population-based study, participants were 845 first-year police recruits (age: 21.2 ± 2.3 years; height: 178.1 ± 10.2 cm; weight: 78.4 ± 11.3 kg; body mass index: 24.7 ± 3.2 kg/m2; 609 men and 236 women; 72.1% men and 27.9% women) measured in 2 conditions: (i) "no load" and (ii) "a 3.5 kg load." Spatiotemporal gait parameters were derived from the FDM Zebris pressure platform. Asymmetry was calculated as (xright-xleft)/0.5*(xright + xleft)*100%, where "x" represented a given parameter being calculated and a value closer to 0 denoted greater symmetry. When compared to "no load" condition, a standardized 3.5 kg/7.7 lb load significantly increased asymmetries in spatial gait parameters as follows: gait phases of stance (mean diff. = 1.05), load response (mean diff. = 0.31), single limb support (mean diff. = 0.56), pre-swing (mean diff. = 0.22), and swing (mean diff. = 0.90) phase, while no significant asymmetries in foot rotation, step, and stride length were observed. For temporal gait parameters, we observed significant asymmetries in step time (mean diff. = -0.01), while no differences in cadence and gait speed were shown. The findings indicate that the additional load of 3.5 kg/7.7 lb is more likely to increase asymmetries in spatial gait cycle components, opposed to temporal parameters. Thus, external police load may have hazardous effects in increasing overall body asymmetry, which may lead to a higher injury risk and a decreased performance for completing specific everyday tasks.

A minimalist elastic metamaterial with meta-damping mechanism

A novel elastic mechanical metamaterial with extreme damping performance has been achieved skillfully by coupling snap-through and pseudo-constant-force behaviors. The proposed meta-damping mechanism is systematically expounded to tailor synthetical force–displacement response for programming hyper energy dissipations. Within this framework, detailed designs in functional sub-structures and collaborative design strategy combined with parametric optimization in integrated structure are further presented synthetically. By additive manufacturing and loading–unloading cyclic experiments, the physical realization of meta-damping elastic metamaterials reveals the extraordinary specific damping capacity (Ψ=7.03), which exceeds any research reported previously and is immensely close to the theoretical limit. Remarkably, this minimalist design method, with only two necessary functional components, reconciles the contradiction between load-bearing and damping dissipation, with strong multi-directional and periodic expansibility. This work has far-reaching implications on the compact design of recoverability, reusability, frequency-independent, material-independent elastic mechanical metamaterials for superior dynamic applications such as impact absorption, vibration reduction, and energy trapping.

Analysis of Urbanization-Induced Land Subsidence in the City of Recife (Brazil) Using Persistent Scatterer SAR Interferometry

The article addresses anthropogenic and geological conditions related to the development of soil subsidence in the western zone of Recife (Brazil). Over the past 50 years, human activity has intensified in areas previously affected by soft soils (clay, silt, and sandstone) resulting in subsidence due to additional loads (landfills and constructions). The duration of the settlement process can be significantly influenced by the specific characteristics of the soil composition and geological conditions of the location. This work presents, for the first time, accurate InSAR time series maps that describe the spatial pattern and temporal evolution of the settlement, as well as the correlation with the geological profile, and validation with Global Navigation Satellite System (GNSS) data. Persistent Scatterer Interferometry (PS-InSAR) was employed in the analysis of Single Look Complex (SLC) images generated by 100 ascending COSMO-SkyMed (CSK) and 65 PAZ (32 ascending, and 33 descending) from the X-band, along with 135 descending Sentinel-1 (S1) acquisitions from the C-band. These data were acquired over the period from 2011 to 2023. The occurrence of subsidence was identified in several locations within the western region, with the most significant displacement rates observed in the northern, central, and southern areas. In the northern region, the displacement rates were estimated to be approximately −20 mm/year, with the Várzea and Caxangá neighborhoods exhibiting the highest rates. In the central region, the displacement rates were estimated to be approximately −15 mm/year, with the Engenho do Meio, Cordeiro, Torrões, and San Martin neighborhoods exhibiting the highest rates. Finally, in the southern region, the displacement rates were estimated to be up to −25 mm/year, with the Caçote, Ibura, and Ipsep neighborhoods exhibiting the highest rates. Additionally, east–west movements were observed, with velocities reaching up to −7 mm/year toward the west. These movements are related to the lowering of the land. The study highlights that anthropogenic effects in the western zone of Recife contribute to the region’s vulnerability to soil subsidence.

Дослідження режимів розгону автомобіля Skoda Octavia на роликовому стенді

As you know, the main characteristics that determine the state of the power unit are the power level and torque. These parameters affect the dynamic qualities of the car and can also play a role in fuel consumption and emission levels. To check these characteristics, traction roller stands of the inertial type are used. These stands allow you to simulate real traffic conditions and loads. Usually, on such stands, the traction force on the driving wheels is measured, which makes it easy to calculate the power in certain driving modes. However, creating a full-fledged load on the driving wheels of the car being diagnosed requires the use of powerful loading and driving devices. This significantly increases the cost of the stand and its metal content. An alternative to this method is the compressed acceleration method. In this method, the load is created by a relatively small inertial mass together with a loading and driving device of moderate power. The diagnostic parameter in this method can be traction force on the wheels, acceleration, time or path of acceleration of the wheels in the selected speed range. For measurement accuracy, it is better to use acceleration time. However, all the advantages of the method can be manifested only with the correct choice of test modes. During testing, results depend on the accuracy and stability of maintaining the test mode. Acceleration time will be measured more accurately, the slower the wheels and rollers of the stand accelerate. During the tests, it is necessary to choose the high-speed measurement mode to ensure a sufficiently stable torque value. The article analyzes the acceleration modes of a car on a roller stand and their influence on the accuracy of diagnostics. The smallest error is achieved when measuring acceleration time from 50 to 70 km/h in IV gear with additional load or in V gear without load.

Physiological Responses in Trail Runners during a Maximal Test with Different Weighted-Vest Loads.

During some trail running races, athletes have to carry hydration support, food, and technical and safety equipment, which generates an additional load that must be mobilized during the race. The aim of the present study was to determine the physiological responses to overload running and the effect they may have on metabolic zones. Seventeen well-trained male trail runners (n = 17) completed three maximal treadmill tests with weighted vests at 0%, 5%, and 10% of their body mass (L0, L5, and L10). Their gas exchange was monitored to assess their ventilatory thresholds 1 (VT1) and 2 (VT2), maximal fat oxidation zone (FatMax), and peak oxygen consumption (VO2peak). Their heart rate (HR), power, and velocity (V) were tracked to compare their behavior. One-way ANOVA showed significant differences in the V (p < 0.001; ηp2 = 0.4620) as a limitation for reaching the peak velocity (Vpeak), with a significant decrease in the Vpeak with the L10 compared to the L0 (p = 0.002) and L5 (p = 0.004). In addition, one-way ANOVA showed significant differences in the peak absolute power (p < 0.001; ηp2 = 0.468) among the groups, detecting higher power production between the L10 and L0 (p < 0.001) and between the L10 and L5 (p = 0.015). Loads higher than L5 could generated important physiological and mechanical modifications, while a load of L5 managed to maintain the working conditions without overloading. These insights shed light on nuanced strategies for optimizing performance and endurance, offering valuable considerations for athletes seeking to enhance their training regimens during overload conditions.

МИГРАЦИИОННАЯ АКТИВНОСТЬ 137CS В АГРОПРОДУКЦИЮ БИОГЕОЦЕНОЗОВ КРАСНОЯРСКОГО КРАЯ

The purpose of the study is to determine the intensity of 137Cs movement along the trophic chain “soil – diet – livestock products” in the agricultural landscapes of the Krasnoyarsk Region with additional radiation load. A literature review of scientific data characterizing the features of the migration activity of 137Cs in the links “soil – feed – livestock products” in agrobiocenoses with radioactive contamination above established standards is given. Based on the results of a radioecological survey of agricultural landscapes in the central regions of the Krasnoyarsk Region and calculation of absorbed doses, the author identified agricultural landscapes with additional technogenic pollution and determined the specific activity of 137Cs in feed and cow's milk in agricultural landscapes with additional technogenic load. The specific activity values of 137Cs in agricultural landscape feeds with doses of 1.33 and 1.55 mGy/year are higher than the background va¬lue for the Krasnoyarsk Region. The content of 137Cs in livestock products produced in farm biogeocenoses with additional technogenic load is higher than the average for the region, but does not exceed the criterion of regulatory documents; accordingly, radiation-safe agricultural products are produced on the territory of the Krasnoyarsk Region. For agricultural landscapes with absorbed doses of 1.33 and 1.55 mGy/year, a KP for the link “feed – livestock products” has been established. When the radioecological situation changes, the established Kp values can be used to predict the migration of 137Cs in the chain “soil – feed – livestock products”. A direct linear moderate Spearman rank correlation was identified between the specific activity of 137Cs in feed and the concentration of 137Cs in cow's milk. Linear regression equations have been determined to determine the specific activity of cow's milk based on data on the specific activity of 137Cs in feed. The revealed direct linear relationship indicates that even a slight increase in the 137Cs activity of the diet leads to an equivalent increase in the specific activity of technogenic cesium in cow's milk.

Research on Mechanism of Non-Uniform In-Situ Stress Induced Casing Damage Based on Finite Element Analysis

Casing damage is a common problem encountered during oil and gas field development due to the complex stress state of the casing. Despite the large number of studies focusing on this problem, the mechanism of non-uniform in-situ stress-induced casing damage in a low-permeability reservoir is still unclear. In this study, casing damage due to non-uniform in-situ stress variations was investigated, and then the tectonic stress coefficients in the study area were determined by an in-situ stress inversion technique, which led to the derivation of formulas for calculating the maximum and minimum horizontal in-situ stresses. Subsequently, finite element numerical simulations were performed to assess the stress distribution during the formation of the casing cement sheath in a G155 block, a typical low-permeability reservoir. The results indicate that casing damage is caused not only by non-uniform in-situ stresses but also by various additional creep-induced loads. Subsequent finite element investigations into casing behavior under mudstone creep conditions indicated that immersion of mudstone in water instigated further shearing and deformation of the casing, culminating in premature well failure prior to water inundation. Notably, Von Mises stress levels exhibited a positive correlation with injection production ratios, with values exceeding critical thresholds leading to distinct modes of mechanical failure including shear-induced deformations, longitudinal tensile stress, and localized yielding near water wells. Maintenance of an optimal injection production ratio is identified as a key strategy for prolonging casing longevity in the region. To this end, recommendations include augmenting the casing wall thickness or enhancing the steel pressure specifications to mitigate casing damage progression, thereby extending the operational lifespan. This research serves as a pivotal theoretical framework for informing future development strategies aimed at mitigating and preempting casing failures in a low-permeability reservoir.

Fuzzy logic-based estimation model of distribution transformers aging

Currently, we are moving towards more ecological modes of transport. As a result, the demand for electric vehicles is growing exponentially, and new loads, related to charging, can negatively affect the operation of electrical grids and their elements. Concurrent and uncontrolled charging of electric vehicles can cause a blackout. Considering the stochastic nature of the additional load from electric cars, it is difficult to predict such a load by analytical methods. The fuzzy logic approach can be used to formalize the tasks with ambiguity. In this paper, a fuzzy-based block diagram of the algorithm was developed in the MATLAB-Simulink environment for evaluating the impact of the charging load of electric vehicles on the aging of transformers, as well as a model was built and the effect of various penetrations of electric cars was evaluated. The fuzzy logic-based model includes the effects of ambient temperature, power quality, and overloads. It contains a diagnostic part that warns the dispatcher of the power distribution network about possible problems, providing up-to-date information about the state of the transformer. In addition, the efficiency of photovoltaic generators to increase the service life of distribution transformers was analyzed. The results show that photovoltaic power plants are not effective enough for high levels of electric vehicle penetration, and more advanced strategies should be used.

Simulation of a scintillator-based fast ion loss detector for steady-state operation in Wendelstein 7-X (invited).

A quantitative theoretical framework has been created to model neutral beam injection and fast ion losses in the Wendelstein 7-X (W7-X) stellarator, including a novel method to develop synthetic diagnostics for fast ion loss detectors (FILDs) of many types, such as scintillating and Faraday Cup FILDs. This is the first time that this has been done in stellarator geometry with this level of fidelity, providing a way for fast ion losses to be predicted more precisely in future stellarator experiments and in W7-X. Simulations of the signal seen by a Faraday Cup FILD have been completed for multiple W7-X plasmas and show close agreement with the measured signals. This method is now applied to an actively water-cooled, scintillator-based FILD, which is currently in development to measure the fast ion loss distribution in W7-X in greater detail. The design makes use of a double slit to measure energy-and-pitch-angle-resolved losses of both co-going and counter-going fast ions. The diagnostic, which can be inserted to different radial positions, has been designed to withstand steady-state heat fluxes of up to 120 kW/m2 along with additional transient heat loads of 100 kW/m2 lasting for up to 20s at a time. Simulations of W7-X standard magnetic configuration show up to 8 × 1013 (s-1 cm-2) ion fluxes onto the sensor from each neutral beam source and no signal from the counter-going slit. These simulations will help inform experimental proposals for future W7-X campaigns after installation of this diagnostic.

Design and laboratory evaluation of spring washers as railway baseplate hold-down method to mitigate spike failures

The rising popularity of elastic railroad fasteners for use in timber sleeper tracks, delineated through their wide adoption across the North American freight network, is facing resistance since the derailment data attributes at least 13 derailments in last two decades to spike failures in sleepers leveraging these elastic fasteners. Previous investigations of the spike failure mechanism illustrated that rail baseplate uplift induced by the rail’s wave-action during a train pass reduces friction at the plate-sleeper interface. This loss in friction transfers additional load (e.g., lateral and longitudinal) to spikes and causes the stress levels to exceed the endurance limits. Although installation of spikes with spring washers was suggested to restrain the baseplate uplift, the industry recommended Fe6 washers demonstrate inadequate resiliency (i.e., working range) resulting in failure to maintain the required hold-down load over time. To characterize the appropriate spring washer for spike failure mitigation, this paper presents an overview of the design criteria driven by engineering design standards while accommodating the standard fastener components. Moreover, this study quantifies the load and resiliency demands from spring washers based on spike pullout experiments as well as existing correlations and pertinent studies in the literature. Consequently, the maximum and minimum recommended hold-down installation loads are 22.2 kN (5000 lbs) and 4.5 kN (1000 lbs.), respectively, to protect the sleeper from premature failure while simultaneously reducing spike stress by 70%. To identify a washer that has an adequate working range, static compression experiments were carried out on a set of nine commercial and non-commercial washers. Results indicate that at least two of the washers considered – the Fe19 and polyurethane washer – can achieve working ranges that are 69% and 93% wider, respectively, with a 68% reduced timber stress compared to the baseline Fe6 washer. Results of this work provide insights into the selection of proper spring washer and the magnitude of installation load to mitigate spike failures.