Search

Abstract Ni-rich layered oxides (LiNi x Co y Mn1−x−y O2, x > 0.8, NCM) are technologically important cathode (i.e., positive electrode) materials for next-generation high-energy batteries. However, they face challenges in cycle stability and durability due to internal strain accumulation and particle fracture as the batteries cycle. Here we report a simple molten-salt-assisted synthesis route to introduce gradiently distributed pores into the polycrystalline NCM secondary particles. The gradient porous strategy creates void spaces to buffer the anisotropic volume change of the primary particles, effectively mitigating the intergranular fracture and limiting the impedance growth. It not only increases the maximum accessible capacity of the NCM cathodes but also greatly enhances their cycle stability in practical pouch-type batteries and all-solid-state-batteries. It further enables a high nickel, low cobalt cathode (LiNi0.96Co0.02Mn0.02O2) with a combination of high specific energy (941.2 Wh kg−1 based on cathode weight at 0.1 C and 25 °C, 1 C = 245 mA g−1) and high stability during cycling (80.5% capacity retention after 800 cycles at 1 C relative to that of the first cycle) and high-temperature storage (reversible capacity retention >95.5% after 42-day storage at 60 °C at the fully charged state) in pouch cells.

LNG corrugated hoses have better flexible mechanical properties and compliance. However, due to the influence of its outline structure and the large heat transfer coefficient, large heat loss is caused during LNG transportation, with the transportation efficiency reduced. Therefore, the flow and heat transfer characteristics of LNG in the plain tube and the corrugated hoses with 5 types of different structural parameters were analyzed with the numerical simulation method. Meanwhile, the influence laws of the corrugation depth, corrugation pitch and Reynolds number on the heat transfer characteristics of the hoses were explored, and the heat transfer characteristics of the hoses were characterized with the thermal performance evaluation criterion(PEC). The results show that: The corrugated hoses have higher Nusselt number, greater friction coefficient and better heat transfer characteristics than the plain tubes. The Nusselt number in the corrugated hoses increases with the increase of Reynolds number, while the friction coefficient decreases with the increase of Reynolds number and becomes stable at high Reynolds number. Under the same Reynolds number, the Nusselt number of the corrugated hoses increases with the increase of the corrugation depth, but decreases with the increase of the corrugation pitch. Besides, the friction coefficient is proportional to the change of the corrugation depth and pitch, and the corrugation depth has the greatest influence. Generally, the research results could provide theoretical guidance for the engineering application and the structural optimization design of LNG cryogenic corrugated hoses.

Abstract The development of pedestrian signal lights made it a promising information center to distribute information to assist safe road crossing and provide “controlled engagement” to improve waiting experience. To determine what types of information to display, this study surveyed 555 pedestrians on frequency of their existing activities while waiting at a red light and preference of several types of information based on results of a structured interview. Pedestrian reported 14 types of activities, from which the four categories with decreasing frequency were extracted based on factor analysis: scene perception, recreation, mental activity, and anxiety activity. The participants reported more mental and anxiety activity have higher need for external displayed information on signal lights. Overall, among the four information categories extracted from 24 specific information types with factor analysis, pedestrians preferred road crossing and contextual information the most, with less preference on learning and appreciation information. The least preferred information is entertainment information, within which they even disliked entertainment news and general commercial ads ( vs. local ones). There are also individual differences in preference for these information categories. The findings have implications on information design for the roadside signal lights as well as advanced traveller information system in general.

Conditional automated driving [level 3, Society of Automotive Engineers (SAE)] requires drivers to take over the vehicle when an automated system’s failure occurs or is about to leave its operational design domain. Two-stage warning systems, which warn drivers in two steps, can be a promising method to guide drivers in preparing for the takeover. However, the proper time intervals of two-stage warning systems that allow drivers with different personalities to prepare for the takeover remain unclear. This study explored the optimal time intervals of two-stage warning systems with insights into the drivers’ neuroticism personality. A total of 32 drivers were distributed into two groups according to their self-ratings in neuroticism (high vs. low). Each driver experienced takeover under the two-stage warning systems with four time intervals (i.e., 3, 5, 7, and 9 s). The takeover performance (i.e., hands-on-steering-wheel time, takeover time, and maximum resulting acceleration) and subjective opinions (i.e., appropriateness and usefulness) for time intervals and situation awareness (SA) were recorded. The results showed that drivers in the 5-s time interval had the best takeover preparation (fast hands-on steering wheel responses and sufficient SA). Furthermore, both the 5- and 7-s time intervals resulted in more rapid takeover reactions and were rated more appropriate and useful than the 3- and 9-s time intervals. In terms of personality, drivers with high neuroticism tended to take over immediately after receiving takeover messages, at the cost of SA deficiency. In contrast, drivers with low neuroticism responded safely by judging whether they gained enough SA. We concluded that the 5-s time interval was optimal for drivers in two-stage takeover warning systems. When considering personality, drivers with low neuroticism had no strict requirements for time intervals. However, the extended time intervals were favorable for drivers with high neuroticism in developing SA. The present findings have reference implications for designers and engineers to set the time intervals of two-stage warning systems according to the neuroticism personality of drivers.

Driver’s situation awareness (SA) is one of the key elements that affect driving decision-making and driving behavior. SA is influenced by many factors, and previous studies have focused only on individual factors. This study presents a comprehensive study to explore the path relationships and influence mechanism between SA and all influential factors, including road characteristics, driver characteristics and states, distracting elements, and cognitive ability. A structural equation model that relates SA to its influential factors is developed. A total of 324 valid questionnaires were collected to analyze and identify the relationships between the factors. The results show that the preceding influential factors have significant effects on SA, which is consistent with previous research. Based on path coefficients, positive effects were: cognitive abilities (0.500), driver state (0.360), age (0.277), driving experience (0.198), and gender (0.156). Negative effects were: distracting elements (−0.253) and road characteristics (−0.213). The results of this comprehensive study provide a valuable reference for the development of driver training programs and driving regulations.

Research on the acquisition of spatial knowledge not only enriches our understanding of the theory of spatial knowledge representation but also creates practical value for the application of spatial knowledge. The aim of this study is to understand the impact of different learning methods on the acquisition of spatial knowledge, including the role of 2D maps, the difference between physical interaction and virtual interaction, and whether passive learning can replace active learning in virtual environments. One experiment was conducted, in which landmark knowledge and configurational knowledge were measured. Results indicate that 2D maps play a supporting role in acquiring both landmark knowledge and configurational knowledge. In addition, physical learning was associated with better spatial knowledge representation compared with virtual learning. An analysis of observational data in the third comparison found no significant difference between passive learning and active learning using virtual street view maps. However, with high-quality learning materials, passive learning can contribute to the acquisition of spatial knowledge more efficiently than active learning.

Speed estimation of drivers' own vehicles and other vehicles on the road is an important task for drivers and is also crucial to the roadway safety. The objective of the study was to examine the effects of multiple factors such as image scale, speed, road type, driving experience, and gender on the speed perception of drivers' own vehicles.Thirty participants consisted of 17 males and 13 females, including 13 without driving experience. All participants estimated the driving speed of 192 5-second video clips, which were selected from naturalistic driving recordings. The recorded driving speeds were evenly distributed across the entire range from 5mph to 65mph. Half of the selected video clips were recorded on wide roads and another half were recorded on comparatively narrow roads. Video clips were played on a large screen, with each clip shown in one of 4 image scales (100%, 75%, 50%, and 38% of the actual field of view in the real world).Speed estimates were most accurate for the smallest image size (38% of the actual field of view). As the image size increased, the driving speed was increasingly underestimated. Participants with driving experience accurately estimated the driving speed on both wide and narrow roads whereas those without driving experience had greater underestimates on wider roads. Speeds were most accurately estimated within the range 25-35mph, but the speeds slower than the range tend to be overestimated and the speeds faster than the range are more likely to be underestimated. While males and females showed the same pattern across speed groups, females have greater estimation errors at the highest and lowest speed groups. Participants without driving experience showed increasing underestimation of speed as driving speed increased whereas participants with driving experience primarily underestimated the highest speeds.The present study shows the effect of multidimensional influential factors on perceived vehicle speed from drivers' perspective. The results also have implications for driving simulation scenario design, driving simulator setup, and the assessment of speed control in simulated and naturalistic environments.

While much research has investigated the predictors of operators' performance such as personality, attitudes and motivation in high-risk industries, its cognitive antecedents and boundary conditions have not been fully investigated. Based on a multilevel investigation of 312 nuclear power plant main control room operators from 50 shift teams, the present study investigated how general mental ability (GMA) at both individual and team level can influence task and safety performance. At the individual level, operators' GMA was predictive of their task and safety performance and this trend became more significant as they accumulated more experience. At the team level, we found team GMA had positive influences on all three performance criteria. However, we also found a "big-fish-little-pond" effect insofar as team GMA had a relatively smaller effect and inhibited the contribution of individual GMA to workers' extra-role behaviors (safety participation) compared to its clear beneficial influence on in-role behaviors (task performance and safety compliance). The possible mechanisms related to learning and social comparison processes are discussed.