107 research outputs found
Transient wave-induced pore-water-pressure and soil responses in a shallow unsaturated poroelastic seabed
No full text10.1017/jfm.2022.184JOURNAL OF FLUID MECHANICS93
DEM Analysis of Railtrack Ballast Degradation under Monotonic and Cyclic Loading
No full textAbstractThe deformation and the degradation of ballast significantly affect the performance of the railway track. In this study, the discrete element method (DEM) was used to investigate the deformation behavior and degradation characteristics of ballasts under monotonic and cyclic loading. The ballasts were simulated as crushable aggregate which is modeled by bounded discrete elementary particles together and it can be crushed under external forces. The flaw of the aggregate was also modeled by randomly distributed void. Conventional monotonic and cyclic triaxial tests were carried out to investigate the crushing of the aggregates and the associated mechanical behaviors. The effects of confining on the crushing of aggregates and the mechanical behavior were also analyzed. It was found that the permanent deformation of the aggregates significantly increases when particle crushing is considered. The crushing of aggregate is most significant in the first two or three cycles
Impact of Seepage on the Underground Water Level in a Complex Soil-Water-Structure System
No full textThe antifloating design of underground structures is very important in areas with high underground water levels, and reasonable evaluation of the buoyancy is based on accurately describing the distribution of the groundwater level. However, the natural groundwater flow would be disturbed by the structure, which is not considered in the antifloating design. In the present paper, the influence of the width of an underground structure on the groundwater level in homogeneous soil is investigated through an indoor physical model test in the first place, which serves as a benchmark for the numerical simulation. Then, the parametrical study is carried out with numerical simulation. The results show that the width of the structure has the greatest influence on the water level around the structure, followed by the influence of the insertion depth, whereas the length has little influence. The hydraulic gradient has a significant effect on that as well. Moreover, the hydraulic conductivity ratio between different soil layers also affects the water level magnitude. Based on the results, a prediction method for the groundwater level around the structure for both homogeneous soil and multilayer soil has been developed and evaluated
Dyeing Performance of Yellow Pigment from Ginkgo Biloba Leaves on the Cannabis/ Mulberry Fiber/Wool fiber Blended Yarn
No full textSustainable Exploitation of Dominant Fishes in the Largest Estuary in Southeastern China
No full textGlobally, marine fisheries have declined under multiple stresses including overfishing, climate change, and habitat degradation. The Min River Estuary, as the largest estuary in southeastern China, has confronted this situation over recent decades. In this study, the dominant species of fish stocks in the Min River Estuary, including Coilia mystus, Cynoglossus abbreviates, Collichthys lucidus, Amblychaeturichthys hexanema, Polydactylus sextarius, Harpodon nehereus, and Secutor ruconius, were evaluated by the length-based Bayesian biomass estimator method (LBB). Outcomes could be grouped into three categories as healthy, showing the lowest exploitation rate (E: 0.31–0.43) and highest relative biomass (B/Bmsy: 1.30–1.90), including S. ruconius, C. mystus, and H. nehereus; overfished, with a medium E (0.50–0.58) and B/Bmsy (0.68–0.79), including A. hexanema and C. abbreviates; and collapsed, with the highest E (0.89–0.92) and lowest B/Bmsy (0.03–0.21), including C. lucidus and P.sextarius. Corresponding imperative countermeasures such as using larger-sized mesh gears and reducing fishing intensity should be deployed according to the current status of each species for sustainable fishery exploitation and fish conservation
Sulfolane in contaminated sites: Environmental toxicity and bioremediation technologies
No full textSulfolane is widely used around the world as an industrial solvent for purifying sour natural gas. However, due to accidental spillage and improper on-site storage/disposal procedures, reports of groundwater, aquifer, and soil contaminations have raised concerns about its potential impacts on humans and the ecosystem. As a contaminant of emerging concern, there is a lack of information on the human toxicity of sulfolane. Several bioremediation technologies have been conducted to assess the biodegradation potential of sulfolane in contaminated groundwater and soils. This review presents and discusses the available literature on the toxicity of sulfolane which could be useful for developing proper sulfolane guidelines in different media. The oral LD50 of sulfolane varied from 0.6 to 3.5 g/kg body weight for different mammalian species including guinea pig, mouse, rabbit, and rat. In addition, a review of various sulfolane bioremediation studies to date is also presented highlighting the efficacy of aerobic versus anaerobic bioremediation of sulfolane at contaminated sites. The zero-order biodegradation rate of sulfolane varied from 0.033 to 190 mg/L/day depending on the initial sulfolane concentration, nutrients, oxygen levels, temperature and other parameters. Effective aerobic treatment technologies can lead to the complete mineralization of sulfolane with sulfuric acid as its major end by-product. Furthermore, the application of aerobic granulation as a promising biotechnology for sulfolane biodegradation is also discussed. This review further discusses the significance of utilizing sulfolane degrading bacteria to reduce treatment times and presents information for future researchers and scientists on specific isolates recorded.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Relative Entropy-Based Constant-Envelope Beamforming for Target Detection in Large-Scale MIMO Radar With Low-Resoultion ADCs
No full textpeer reviewe
State of Health Estimation of Lithium-Ion Battery Using Multi-Health Features Based on Savitzky–Golay Filter and Fitness-Distance Balance- and Lévy Roulette-Enhanced Coyote Optimization Algorithm-Optimized Long Short-Term Memory
No full textAccurate and reliable state of health (SOH) estimation is extremely crucial for the safe and stable operation of lithium-ion batteries (LIBs). In this paper, a method based on Lévy roulette- and fitness-distance balance-enhanced coyote optimization algorithm-optimized long short-term memory (LRFDBCOA-LSTM) is employed for SOH estimation of LIB. Firstly, six health features are extracted from battery charging and discharging data, and Savitzky–Golay is used to filter the feature data to improve correlation between feature and SOH. Then, Lévy roulette and fitness-distance balance (FDB) strategies are used to improve the coyote optimization algorithm (COA), i.e., LRFDBCOA. Meanwhile, the improved algorithm is used to optimize the internal parameters of long short-term memory (LSTM) neural network. Finally, the effectiveness of the proposed model is comprehensively validated using five evaluation indicators based on battery data obtained under three different testing conditions. The experimental results manifest that after algorithm improvement and network parameter optimization, the performance of the model is significantly improved. In addition, the method has high estimation accuracy, strong generalization, and strong robustness for SOH estimation with a maximum R2 of 0.9896 and minimum R2 of no less than 0.9711
Research on Safety and Traffic Efficiency of Mixed Traffic Flows in the Converging Section of a Super-Freeway Ramp
No full textOn-ramp merging areas are essential parts of freeways. The merging behavior of vehicles is the main factor affecting the continuity of freeway traffic flow, which determines the capacity of the main freeway line. With the development of innovative car technology, ACC technology has been widely used in actual vehicles. At the same time, the public’s demand for freeway-speed improvement is increasing. However, the evaluative research on freeway-speed-improvement schemes, safety, and efficiency, is incomplete. Therefore, this paper aims at the study of the mixed traffic flow of ACC and human-driven vehicles, simultaneously increasing the maximum speed limit to 140 km/h, and establishes a ramp-entry model through the SUMO simulation platform. The traffic-flow parameters upstream of the ramp entry and downstream of the weaving area are analyzed, including the flow, average speed, headway, and lane-change rate. The influence of the driving conditions for mixed ACC vehicles with different proportions in the ramp-merging scenario is analyzed from efficiency and safety perspectives. Studies have shown that mixing ACC vehicles can improve the safety and efficiency of the road, and the increase in the maximum speed limit has limited road capacity. When considering the inclusion of ACC vehicles, increasing the maximum speed limit can improve the operating efficiency of the road
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