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This study provides an approach to identify driving style of truck drivers by using GPS, load condition, and in-vehicle monitoring data and investigates the association of driving styles with risky driving behaviors from macro and micro perspectives. The naturalistic driving data used in this study were collected from 4,357 trucks in Hangzhou, China over three months in 2021. Six driving volatility parameters and six warning parameters were used to characterize the driving styles. Then, three driving styles under the two load conditions were identified using k-means clustering methods and principal component analysis. Finally, one-way MANOVA and ANOVA were used to analyze the relationship between driving styles and driving risk. It was found that truck drivers have different thresholds for aggressive and cautious driving style under different load conditions. Truck drivers who exhibited aggressive driving under both load conditions exhibited high driving risk. Although most truck drivers exhibited safe or normal driving under both conditions, the few who exhibited aggressive driving contribute to a disproportionate driving risk. These results can help distinguish differences in truck drivers' driving styles under different load conditions, thus providing a more comprehensive safety assessment of truck drivers' performance for monitoring purposes. [ABSTRACT FROM AUTHOR]

As the second part of the investigation on vibration characteristics of ± 800 kV converter transformers, this part focuses on load conditions. A full-load thermal stability test is carried out on 12 YY and YD converter transformers in a converter station. Vibration, voltage, current, and other important information are collected by online monitoring devices. Vibration amplitude, vibration spectrum, dominant frequency, vibration power ratio of frequency band, vibration power entropy, and odd–even harmonic ratio under different load conditions are calculated and studied to evaluate the vibration state. Theoretical analyses of winding electromagnetic force and vibration acceleration are carried out and results show that the harmonic currents make the dominant frequency shift to 300 Hz or 400 Hz. Most vibration characteristics are sensitive to load rate changes. The odd–even harmonic ratio is sensitive to filter disconnection and reconnection. The results of this study reveal the vibration regularity and corresponding mechanism and can contribute to further study on vibration assessment of ± 800 kV converter transformers under load conditions.

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• Propose an algorithm to determine travel time between two adjacent nodes. • Account for planning time with varying acceleration and deceleration. • Develop an algorithm to sequence arrival times as a vehicle approaches a node. In previous studies, the behaviour of each vehicle is assumed to be constant in all situations. However, this assumption is unreasonable, as physical factors—such as load conditions or turn times—are not considered in the trajectory planning process, even though they significantly affect vehicle operation. Therefore, an algorithm for determining travel time between two adjacent nodes (A2D2T-A2AN) is proposed to resolve collisions caused by discrepancies between planned time and actual time, which make these collisions unpredictable. Additionally, vehicles can be controlled with varying accelerations depending on load conditions. Furthermore, an algorithm to adjust arrival times when a vehicle approaches a node (A2CAT-VT2N) is developed. To verify the efficiency and feasibility of these algorithms, several experiments were conducted using a chessboard map simulation under different conditions. The results demonstrate that our method is both suitable and effective for real-world applications. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, two types of piezoelectric structures A and B are designed for harvesting maximum amount of energy from motor vibrations. The analysis is conducted under various load conditions with the placement of two different shapes of proof mass (square and rectangular) on the piezoelectric energy harvester. An experimental study is conducted for harvesting energy from motor vibrations using two piezoelectric structures A and B, in which, structure B with the placement of square-proof mass generates maximum power, which is efficient for powering low-power electronic applications. [ABSTRACT FROM AUTHOR]

In a cross-country skiing competition, the time difference between the winner and the skier coming in at second place is typically very small. Since the skier spends much of the energy on overcoming resistive forces, a relatively small reduction in these forces can have a significant impact on the results. The resistive forces come partly from the friction, at the tribological interface between the ski and the snow, and as with many tribological processes, the characterisation of its origin plays an important role in determining the frictional properties. Furthermore, in cross-country ski friction, there are several scales impacting the frictional performance, with the major contributors being the ski-camber profile and ski-base structure. Macro-scale measurements of the ski-camber profile under loading are often used to determine how adequate the ski is for use under specific conditions. The characteristic properties usually assessed are the force required to collapse the ski in order to obtain a certain camber height, the topography of the kick-wax zone, and the length (determined by simple means) of the frictional interfaces associated with the rear- and front glide zones, i.e., the apparent contact length. These measurements are, however, commonly performed by loading the ski against a much stiffer counter surface than snow and this affects the quantification of the characteristic properties. To date, some mathematical models have been proposed, but there is no reliable approach for determining the macro-scale properties of the contact between a cross-country ski and a counter surface using simulations. In the present paper, an Artificial Neural Network (ANN) has been trained to predict the ski-camber profile for various loads applied at different positions. A well-established deterministic approach has been employed to simulate the contact between the ANN-predicted ski-camber profile and a linearly elastic body with a flat upper surface, representing the snow. Our findings indicate that this method is feasible for the determination of relevant macro-scale contact characteristics of different skis with snow. Moreover, we show that the apparent contact area does not linearly depend on the load and that the material properties of the counter surface also exert a large impact when quantifying the apparent contact area and the average apparent contact pressure. [ABSTRACT FROM AUTHOR]

Defective cell in a PEMFC stack may reduce durability and reliability of the stack and even damage the stack. However, the dynamic performance of defective cell within a PEMFC stack is not clear. In this paper, the dynamic characteristics of the defective cell under different load conditions are analyzed. The results reveal that the defective cell has slower dynamic response rate than other single fuel cells, and the defective cell causes a poor voltage uniformity of the stack. The increased frequency of load change makes the voltage change rate of defective cell higher. The increased amplitude of load change has a more negative impact than the increased frequency of load change, and makes the defective cell more prone to flooding. Furthermore, impedance spectrum shows that these load conditions have greater negative effect for the defective cell than other cells. Finally, according to the experimental results and practical application, recommends related to control strategy of PEMFC stack are proposed to extend lifetime. [Display omitted] • Defective cell has slower dynamic response rate than the normal cell. • Increasing amplitude of loading makes the defective cell more prone to flooding. • Poor voltage uniformity of stack is proven to be caused by the defective cell. • Recommends related to the control strategy are proposed to extend stack lifetime. [ABSTRACT FROM AUTHOR]

In a cross-country skiing competition, the time difference between the winner and the skier coming in at second place is typically very small. Since the skier spends much of the energy on overcoming resistive forces, a relatively small reduction in these forces can have a significant impact on the results. The resistive forces come partly from the friction, at the tribological interface between the ski and the snow, and as with many tribological processes, the characterisation of its origin plays an important role in determining the frictional properties. Furthermore, in cross-country ski friction, there are several scales impacting the frictional performance, with the major contributors being the ski-camber profile and ski-base structure. Macro-scale measurements of the ski-camber profile under loading are often used to determine how adequate the ski is for use under specific conditions. The characteristic properties usually assessed are the force required to collapse the ski in order to obtain a certain camber height, the topography of the kick-wax zone, and the length (determined by simple means) of the frictional interfaces associated with the rear- and front glide zones, i.e., the apparent contact length. These measurements are, however, commonly performed by loading the ski against a much stiffer counter surface than snow and this affects the quantification of the characteristic properties. To date, some mathematical models have been proposed, but there is no reliable approach for determining the macro-scale properties of the contact between a cross-country ski and a counter surface using simulations. In the present paper, an Artificial Neural Network (ANN) has been trained to predict the ski-camber profile for various loads applied at different positions. A well-established deterministic approach has been employed to simulate the contact between the ANN-predicted ski-camber profile and a linearly elastic body with a flat upper surface, representing the snow. Our findings indicate that this method is feasible for the determination of relevant macro-scale contact characteristics of different skis with snow. Moreover, we show that the apparent contact area does not linearly depend on the load and that the material properties of the counter surface also exert a large impact when quantifying the apparent contact area and the average apparent contact pressure.

This study investigates the effect of moving the binding and adjusting the normal load on friction for a modern cross-country ski. The binding was moved 10 cm forward and backward from the normal position. The results showed that moving the binding backward on the ski reduced the friction at cold (−10 °C) and warm air temperatures (+5 °C). At intermediate temperatures (−2 °C), neither changes to the binding position nor the total load affected the friction coefficient. Measurement of pressure zone profiles revealed that moving the binding backward reduced the apparent contact area, increased the average contact pressure, increased the peak pressure in the rear zone and increased the spacing between the front and rear contact zones of the ski. • The friction reduced when the binding was moved backward for the coldest and warmest temperatures. • The friction coefficient was load dependent only for warm and wet snow conditions. • Ski contact properties changed with load and load application point. • A non-linear correlation between the applied normal load and the apparent contact area was found. [ABSTRACT FROM AUTHOR]