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The two-dimensional carbon material graphene oxide （GO） was modified by using quaternary ammonium cationic surfactant dodecyl dimethyl benzyl ammonium chloride （BKC） through π-π interaction to improve its dispersion and stability in aqueous solution. To further enhance the crosslinking effect， the modified GO composites （GB） was coated with polydopamine （PDA） in an alkaline solution. The gelatine/modified graphene oxide/polydopamine composite aerogel （GGB） using biomass material gelatin （Gel） as the skeleton material was prepared by sol-gel method and freeze-drying technique. The micro-morphology and structure of GGB composite aerogel were characterized by SEM， FTIR and XPS， etc. The GGB was used for the adsorption of levofloxacin hydrochloride （LEV） and the adsorption effects were investigated under different conditions such as pH values，contact time，reaction temperature，initial solution concentration，and dosage of adsorbent. Furthermore， the adsorption effects of GGB and composite unmodified graphene oxide aerogel （GGO） on LEV were compared. The results show that the GGB composite aerogel shows excellent adsorption capacity for the LEV， and the LEV adsorption capacity of GGB is increased more than 3 times than that of GGO. Moreover， the adsorption process is a spontaneous exothermic process and the experimental data of the adsorption process are more fitted to the Langmuir isotherm and the pseudo-second-order kinetic model， the theoretical maximum adsorption capacity of LEV on GGB is 476.42 mg/g. After 5 adsorption-desorption cycles， GGB maintained an equilibrium adsorption capacity for LEV exceeding 80 mg/g. It is indicated that the GGB exhibits significant promise as a highly efficient adsorbent for removing of LEV from wastewater.

In order to make magnesium alloys more widely used in modern industry， the research on the corrosion type and mechanism of magnesium and magnesium alloys has become an important goal. In this paper， the research progress on the influence of anions in typical corrosive media on the corrosion behavior of magnesium alloys was systematically summarized. Namely， the corrosion behavior and corrosion reaction mechanism of magnesium alloys in solutions containing chloride ions， sulfate ions， phosphate ions and carbonate ions were introduced， mainly including the study of corrosion behavior of magnesium alloys under typical medium conditions using electrochemical polarization curves， impedance spectroscopy and weight loss methods， as well as the analysis of corrosion causes based on the corrosion mechanism. Finally， the research direction of magnesium alloy corrosion and protection is prospected.

In order to explore the electrochemical reduction reaction process of trivalent chromium ions, ultraviolet visible spectrophotometry (UV - Vis), linear sweep voltammetry (LSV), cyclic voltammetry (CV) and other methods were used to study the existing forms of the coordination compounds at the initial reduction stage of Cr (Ⅲ) ions in choline chloride - ethylene glycol (ChCl - EG) deep eutectic solvent system, the electrochemical reduction reaction process of Cr (Ⅲ) ions, the apparent activation energy of the reduction process of Cr (Ⅲ) ions in the electrolyte and the control steps of the reduction process. Results showed that at the initial reduction stage of Cr (Ⅲ) in deep eutectic solvent, the coordination compounds of [Cr(H2O)3Cl3] and [Cr(H2O)2Cl4 ]- would be preferentially formed, and the [Cr(H2O)2Cl4]- was the main coordination compound. With the increase of the concentration of CrCl3·6H2O, the form of coordination compound had a tendency to partially convert from [Cr(H2O)2Cl4]- to [Cr(H2O)3Cl3], and through an analysis taking into account both this tendency and the dissociation energy, it could be found that the transformation of the coordination compound made the reduction of Cr3+→Cr2+ easier. The reduction of trivalent chromium ions in ChCl - EG deep eutectic solvent was a two - step process: Cr3+→Cr2+→Cr. In the first step, the apparent activation energy was in the range of 12～16 kJ/mol and controlled by the diffusion step. In the second step, the apparent activation energy was in the range of 16～40 kJ/mol and controlled by both electrochemical and diffusion steps.

In this work, the morphology, anti-corrosion performance and degradation mechanisms of two phosphate chemical conversion coatings containing the AEO (fatty alcohol polyoxyethylene ether) and AES (fatty alcohol polyoxyethylene ether sodium sulfate) on an as-cast Mg-8wt.%Li alloy were explored and compared. Although two coating layers had a petal-shaped structure and were composed of leaf-shaped particles, the coating layer of the AES-coated sample was relatively dense due to the smaller size of the formed petal-shaped structure. Based on the electrochemical data and hydrogen evolution measurements, the corrosion protectability of the coating layer on the AES-coated sample was better than that on the AEO-coated sample. The determined corrosion current densities (icorr) of the AES-coated and AEO-coated samples in the 3.5 wt.% NaCl solution were, respectively, 7.8 mA·cm−2 and 11.7 mA·cm−2, whereas the icorr value of the coated sample without a surfactant was 36.2 mA·cm−2. [ABSTRACT FROM AUTHOR]

Research progress on corrosion behavior (localized corrosion, corrosion type and corrosion products) and the effects of processing methods and alloying on the corrosion resistance of hexagonal close packed (HCP) singular phase, body cubic centered (BCC) singular phase and (HCP+BCC) duplex structured Mg-Li alloys were summarized. The future research directions about how to improve the corrosion resistance of Mg-Li alloys were pointed out and the research on corrosion behavior of Mg-Li alloys should focus on the structure, main components and evolution of surface product layers. Meanwhile, it is necessary to consider the effect of alloying elements on the protective effect of surface film layers, and to study the influence of the crystallographic texture of Mg-Li alloys due to the severe plastic deformation on their corrosion behavior.

A control strategy using variable speed limit (VSL) is a proven solution to reduce freeway collision risks and improve safety. However, the heterogeneity of human drivers restricts the effectiveness of traditional VSL controls, which may be made up by recent advanced technologies of connected and automated vehicles (CAVs). This study aims to propose a CAV-based VSL control system to address the limitations caused by human drivers on VSL control's effectiveness. First, the heterogeneity of human drivers is analyzed, and its impact on the safety performance of VSL is examined. Specifically, a microscopic simulation platform is established, and two vehicle dynamic models developed for CAVs and human-driven vehicles (HDVs) are incorporated into the simulation platform. Based on a widely utilized surrogate safety measurement, time-to-collision, its derivative metrics are applied to evaluate collision risks, and the total travel time is used to assess operational efficiency. Extensive simulations are conducted to examine the performance of the proposed CAV-VSL system. The results indicate the following: (1) the heterogeneity of human drivers negatively affects the performance of the VSL; (2) the performance of the proposed control system in a mixed flow can be improved by advanced wireless communication technology; (3) CAVs are able to implement the VSL control strategy effectively resulting in the proactive reduction of the heterogeneity., Author(s): Ye Li [1]; Yuntao Shi [1]; Jaeyoung Lee [1]; Chen Yuan [1,2]; Baojie Wang (corresponding author) [3] 1. Introduction Freeway bottlenecks have attracted considerable attention from transportation researchers since [...]

Considering the great time and labor consumption involved in conventional hazard assessment methods in compiling landslide inventory, the construction of a transferable landslide susceptibility prediction model is crucial. This study employs UAV images as data sources to interpret the typical alpine valley area of Beichuan County. Eight environmental factors including a digital elevation model (DEM) are extracted to establish a pixel-wise dataset, along with interpreted landslide data. Two landslide susceptibility models were built, each with a deep neural network (DNN) and a support vector machine (SVM) as the learner, and the DNN model was determined to have the best pre-training performance (accuracy = 88.6%, precision = 91.3%, recall = 94.8%, specificity = 87.8%, F1-score = 93.0%, and area under curve = 0.943), with higher parameters in comparison to the SVM model (accuracy = 77.1%, precision = 80.9%, recall = 87.8%, specificity = 73.9%, F1-score = 84.2%, and area under curve = 0.878). The susceptibility model of Beichuan County is then transferred to Mao County (which has no available dataset) to realize cross-regional landslide susceptibility prediction. The results suggest that the model predictions accomplish susceptibility zoning principles and that the DNN model can more precisely distinguish between high and very-high susceptibility areas in relation to the SVM model. [ABSTRACT FROM AUTHOR]

Walking, as a healthy and environmentally friendly mode of travel, has been revived in many cities around the world. The mid-block crosswalk (MBC) is a common type of pedestrian facility, and the pedestrian hybrid beacon (PHB) is one of most commonly used signalized MBCs, having a wide range of applications. This study applied an upstream detection (UD) strategy to PHB to reduce the pedestrian waiting time at the crossing. Data were collected through video recordings at two crosswalks at two different periods of the day in the city of Nanjing. First, basic simulation models were developed in VISSIM according to the current layout and the signal control methods of the two crosswalks. Second, signal control logic was adjusted to develop simulation models of PHB. Third, upstream detectors were added to develop simulation models of PHB with a UD strategy. Models for PHB were simulated with 10 different random seeds, and a paired /'-test was conducted to evaluate the performance of the UD strategy statistically. The results show that the UD strategy for PHB reduces pedestrian waiting time and increases vehicle delay. However, the reduction in pedestrian waiting time is greater than the increase in vehicle delay. The UD strategy has also been found to be more effective for crosswalks, with relatively short crossing lengths and low pedestrian volume. Finally, a discussion about factors concerned with the application of UD strategies in practice is carried out., 1. Introduction With the accelerated process of urbanization and the overuse of personal cars, traffic congestion has become a serious problem that negatively affects daily life. Meanwhile, as a healthy [...]