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The conditions and influencing factors of hydrate formation is significant for hydrate technology. Combining with the existing literatures and the experimental data of this work, the phase equilibrium of CO2 hydrate in (NaCl/CaCl2/MgCl2) ionic solutions, pure water-sediment system and (NaCl/CaCl2/MgCl2) ionic solution-sediment systems under the static magnetic field (0.39 T) was studied. Moreover, the effect mechanism of magnetic field on hydrate phase equilibrium in different systems was analyzed in terms of intermolecular interaction. Under the same pressure, the magnetic field increased the phase equilibrium temperature of CO2 hydrate by 2.0–2.8 K in the three ionic solutions, which improved the hydrate formation conditions. This is mainly due to that the magnetic effect increases water activity and weakens the ionic hydration shells, thus promotes hydrate formation. In addition, compared with the ionic solution systems without magnetic field, the magnetic field increased the hydrate phase equilibrium temperature by 0.1–2.5 K in the ionic solution-sediment systems. However, the degree of temperature increase is less than that in the magnetic field-ionic solution systems, which is because the magnetic field enhances the binding between ions and the sediment particle in sediment-bearing systems. Compared with the magnetic field-ionic solution systems, the water activity in the magnetic field-ionic solution-sediment systems is lower, which makes hydrate formation more difficult. Moreover, with the movement of cations and anions in magnetic field, the crystals may be formed due to ion collisions, enhance the capillary action in ionic solution-sediment systems, and then hinder the hydrate formation. Therefore, the sediments can weaken the magnetic field promotion to hydrate formation. [ABSTRACT FROM AUTHOR]

We proposed a passenger control strategy and train operation plan collaborative optimization (PCS&TOP) model to schedule the train operation that improves the efficiency of passengers' travel and reduces the cost of train operation for a rail transit network. The model is an integer non linear programming model that aims to minimize the entrance and platform waiting time of passengers and the operation cost of trains. The timetable and variable train formation are integrated optimized, and the turnaround of rolling stock is also considered by constructing the train operation constraints for the model. The coordination of timetables on different lines and the coordination of passenger control strategies at different stations are mentioned by considering the transfer passengers when constructing the passenger control constraints. To solve the model, a multi-operator simulated annealing (MOSA) algorithm that includes three types of execution operators corresponding to three main decision variables is proposed. A numerical case that includes 2 bidirectional crossed lines and a real-world case from China are introduced to test the efficiency of the proposed method, which demonstrates better performance than the single and respective optimization solutions., Author(s): Yonghao Yin [1]; Jun Chen (corresponding author) [1]; Wenrui Zhao [2] 1. Introduction The rail transit system is developing rapidly in recent years, the passenger demand is increasing greatly, [...]

When passengers are oversaturated in the urban rail transit system and a further increase of train frequency is impossible, passenger flow control strategy is an indispensable approach to avoid congestion and ensure safety. To make the best use of train capacity and reduce the passenger waiting time, coordinative flow control is necessary at each station on a line. In most published studies, the equilibrium of passenger distributions among different stations and periods is not considered. As a result, two issues occur making it hard to implement in practical. First, a large number of passengers are held up outside a small number of stations for very long time. Second, there is a large variation of controlled flows for successive time intervals. To alleviate this problem, a single-line equilibrium passenger flow control model is constructed, which minimizes the total passenger delay. By applying different forms of the delay penalty function (constant and linear), flow control strategies such as independent flow control and equilibrium flow control can be reproduced. An improved simulated annealing algorithm is proposed to solve the model. A numerical case is studied to analyze the sensitivity of the functions, and the best parameter relationship in different functions could be confirmed. A real-world case from Batong Line corridor in Beijing subway is used to test the applicability of the model and algorithm, and the result shows that the solution with linear delay penalty functions can not only reduce the total passenger delay but also equilibrate the number of flow control passengers on spatial and temporal., Author(s): Yonghao Yin [1]; Dewei Li (corresponding author) [2]; Kai Zhao [3]; Ruixia Yang [2] 1. Introduction 1.1. Background With the development of urban rail transit, the number of passengers [...]

A metro disruption is a situation where metro service is suspended for some time due to unexpected events such as equipment failure and extreme weather. Metro disruptions reduce the level of service of metro systems and leave numerous passengers stranded at disrupted stations. As a means of disruption management, bus bridging has been widely used to evacuate stranded passengers. This paper focuses on the bus bridging problem under operational disruptions on a single metro line. Unlike previous studies, we consider dynamic passenger flows during the disruption. A multi-objective optimization model is established with objectives to minimize total waiting time, the number of stranded passengers and dispatched vehicles with constraints such as fleet size and vehicle capacity. The NSGA-II algorithm is used for the solution. Finally, we apply the proposed model to Shanghai Metro to access the effectiveness of our approaches in comparison with the current bridging strategy. Sensitivity analysis of the bus fleet size involved in the bus bridging problem was conducted., 1. Introduction Metro disruptions, usually caused by emergency events such as infrastructure blockages, accidents and extreme weather, have frequently occurred in lots of cities [1]. A disruption is a relatively [...]

Train dwell time estimation is a critical issue in both scheduling and rescheduling phases. In a previous paper, the authors proposed a novel dwell time estimation model at short stops which did not require the passenger data. This model shows promising results when applied to Dutch railway stations. This paper focuses on testing and improving the generality of the model by two steps: first, the model is tested by applying more independent datasets from another city and comparing the estimation accuracy with the previous Dutch case; second, the model's generality is tested by a theoretical approach through the analysis of individual model parameters, variables, model scenarios, and model structure as well as work conditions. The validation results during peak hours show that the MAPE of the mo del is 11.4%, which is slightly better than the results for the Dutch railway stations. A more generalized predictor called 'dwell time at the associated station' is used to replace the square root term in the original model. The improved model can estimate train dwell time in all the investigated stations during both peak and off-peak periods. We conclude that the proposed train dwell time estimation model is generic in the given condition., 1. Introduction Train dwell time estimation is a critical issue for both the scheduling and rescheduling phases. In the scheduling phase, accurate estimation of the train dwell time provides necessary [...]

For dense railway lines, timetables are commonly designed periodically to provide regular services. However, such timetables may lead to many low‐occupancy departures and make it inefficient to a railway company. We combine the features of periodic timetabling with those of demand‐responsive timetabling design for a bidirectional rail transit line considering rolling stock circulation. A mixed‐integer programming model with the objective of minimizing total passenger waiting time and weighted total train travel time is formulated and a three‐phase heuristic algorithm is developed. Five performance indicators, namely, total train travel time, passenger average waiting time, event time deviation, event frequency deviation, and train connection time are introduced to evaluate the performance of the model. A case study on Jinshan railway corridor in Shanghai demonstrates that the proposed demand responsive periodic timetabling model can reduce passengers' waiting time and keep periodicity in the meantime with short computational time [ABSTRACT FROM AUTHOR]

Microalgae are photosynthetic organisms with the ability to produce a variety of high-value compounds such as polyunsaturated fatty acids (PUFAs), proteins, pigments, and lipids. The high cost of microalgae production is one of the biggest obstacles for their commercialization. Plant growth regulators might be an ideal choice since they could potentially induce microalgae to produce lipids and other high-value secondary metabolites thereby reducing production cost. This study investigated the effects of eight plant growth regulators (PGRs), namely, salicylic acid (SA); 1-naphthaleneacetic acid (NAA); gibberellin (GA3); 6-benzylaminopurine (6-BA); 2,4-epibrassinolide (EBR); abscisic acid (ABA); ethephon (ETH); and spermidine (SPD) on the induction of lipids, proteins, carotenoids, and unsaturated fatty acids (UFAs) in Chlorella vulgaris. Moreover, the expression profiles of seven fatty acid biosynthethis genes were studied in the PGR-treated biomass. All PGRs used in the study caused significant increases in total lipid contents in non-dose-dependent manners when compared to control. However, lipid productivities were increased due to four of the eight PGRs (ABA, 6-BA, NAA, and ETH). Similar to lipids, total carotenoid contents were significantly higher in all of the PGR-treated microalgal biomass except ABA. However, soluble protein contents were not affected by the PGR treatments except SA at 10 mg L−1. Furthermore, 6-BA, NAA, ABA, and ETH treatments resulted in significant increases in UFAs especially DHA, linolenic acid, arachidonic acid, and EPA which were confirmed by the upregulation of fatty acid biosynthesis genes including stearoyl-ACP-desaturase, ω-3 fatty acid desaturase, biotin carboxylase, and acyl-acyl carrier protein. Our findings, therefore, indicate that the treatment with PGR used in this study could be a useful tool to produce biodiesel and other high-value metabolites from microalgal biomass. [ABSTRACT FROM AUTHOR]

Synchronization analysis of electroencephalogram (EEG) and electromyogram (EMG) could reveal the functional corticomuscular coupling (FCMC) during the motor task in human. A novel method combining Gabor wavelet and transfer entropy (Gabor-TE) is proposed to quantitatively analyze the nonlinearly synchronous corticomuscular function coupling and direction characteristics under different steady-state force. Firstly, the Gabor wavelet transform method was used to acquire the local frequency-band signals of the EEG and EMG signals recorded from nine healthy controls simultaneously during performing grip task with four different steady-state forces. Secondly, the TE of local frequency-band was calculated and the unit area index of the transfer ( A TE ) was defined to quantitatively analyze the synchronous corticomuscular function coupling and direction characteristics under steady-state force. Lastly, the effect of EEG and EMG signal power spectrum on Gabor-TE analysis was explored. The results showed that the coupling strength in the beta band was stronger in EEG→EMG direction than in EMG→EEG direction, and the A TE values in the beta band in EEG→EMG direction decreased with the force increasing. It is also shown that the difference in TE values of gamma band present a varying regularity as the increase of force in both directions. In addition, EMG power spectrum was significantly correlated with the result of Gabor-TE inspecific frequency band. The results of our study confirmed that Gabor-TE can quantitatively describe the nonlinearly synchronous corticomuscular function coupling in both local frequency band and information transmission. The analysis of FCMC provides basic information for exploring the motor control and the evaluation of clinical rehabilitation.