Transport Line Research Articles

Considerable Unaccounted Local Sources of NOx Emissions in China Revealed from Satellite.

High-resolution (e.g., 5 km) emission data of nitrogen oxides (NOx = NO + NO2) provide localized knowledge of pollution sources for targeted regulations, yet such data are lacking or inaccurate over most regions at present. Here we improve our PHLET-based inversion method to derive NOx emissions in China at a 5-km resolution in summer 2019, based on the TROPOMI-POMINO satellite product of nitrogen dioxide (NO2) columns. With low computational costs, our inversion explicitly accounts for the effects of horizontal transport and nonlinear chemistry. We find numerous small-to-medium sources related to minor roads and small human settlements at relatively low affluence levels, in addition to clear emission signals along major transportation lines, consistent with road line density and Tencent location data. Many small-to-medium sources and transportation emissions are unclear or missing in the spatial distributions of four widely used emission inventories. Our emissions offer a unique reference for targeted emission control.

Visualization of Railway Transportation Engineering Management Using BIM Technology under the Application of Internet of Things Edge Computing

In the past, railway line planning usually required engineers to design based on their own experience after a series of field visits, leading to heavy workload and low efficiency. Moreover, operation and maintenance management is more complicated due to an abundance of railway station equipment. Based on the above problems, this paper first puts forward the railway transportation line planning and design method based on Building Information Modeling (BIM) technology. Besides, LocaSpace Viewer realizes the three-dimensional (3D) visual scene modeling of the railway environment to improve the efficiency of railway line planning and design. Secondly, the railway station’s visual operation and maintenance management system is constructed via BIM Technology. Besides, the Internet of Things (IoT) is combined with edge computing and deep learning technology to build a 3D model of station equipment, collect data in real time, and analyze data efficiently. Finally, the design effect of the model, the performance of the visual management system, and the test results of network transmission delay are displayed and analyzed. The results show that BIM can construct the 3D visualization model with high fidelity for the railway environment. This model can get a reasonable line planning scheme and analyze its feasibility, provide a reliable basis for engineers to plan railway transportation lines, and improve design efficiency. In addition, the GPU occupation rate, CPU occupation rate, and memory occupation rate of the operation and maintenance management system in different operating environments are within the standard range; when multiple clients access the system, the system data access delay is 100% less than 8 ms, which has good performance. Furthermore, the performance of the IoT transmission data real-time scheduling model and the edge computing optimization algorithm applied to this system is better than other popular methods, which can significantly improve the operation efficiency of the system. This study aims to enhance the efficiency of railway transportation line planning and station operation and maintenance management with the help of digital technologies.

The Linear City: illustrating the logic of spatial equilibrium

Linear cities where activity is spread out along a transportation line, aim to offer the highest levels of accessibility to their adjacent populations as well as to the countryside. These city forms are popular amongst architects and planners in envisioning ideal cities but they are difficult to implement as they involve strict controls on development which often ignore human behaviour associated with where we locate and how we move. We briefly explore the history of these ideas, noting the latest proposal to build a 170 km city called Neom in north west Saudi Arabia, a plan that has attracted considerable criticism for its apparent ignorance of how actual cities grow and evolve. We use a standard model of human mobility based on gravitational principles to define a set of equilibrium conditions that illustrate how a theoretical city on a line would, without any controls, successively adapt to such a new equilibrium. First, we represent the city on a line, showing how its population moves to an equilibrium along the line, and then we generalise this to a bigger two-dimensional space where the original line cutting across the grid evolves as populations maximise their accessibility over the entire space. In this two-dimensional world, we simulate different forms that reflect a balance of centralising versus decentralising forces, showing the power of such equilibria in destroying any idealised form. This approach informs our thinking about how far idealised future cities can depart from formal plans of the kind that the linear city imposes.

Evaluation of Drifting Snow Susceptibility Based on GIS and GA-BP Algorithms

Drifting snow, the flow of dispersed snow particles near ground level under the action of wind, is a major form of snow damage. When drifting snow occurs on railways, highways, and other transportation lines, it seriously affects their operational safety and results in drifting snow disasters. Drifting snow disasters frequently occur in the high latitudes of northwest China. At present, most scholars are committed to studying the prevention and control measures of drifting snow, but the prerequisite for prevention is to effectively evaluate the susceptibility of drifting snow along railways and highways to identify areas with a high risk of occurrence. Taking the Xinjiang Afukuzhun Railway as an example, this study uses a geographic information system (GIS) combined with on-site monitoring and surveys to establish a drifting snow susceptibility evaluation index system. The drifting snow susceptibility index (DSSI) is calculated through the weight of an evidence (WOE) model, and a genetic algorithm backpropagation (GA-BP) algorithm is used to obtain optimised evaluation index weights to improve the accuracy of model evaluation. The results show that the accuracies of the WOE model, WOE backpropagation (WOE-BP) model, and weight of evidence genetic algorithm backpropagation (WOE-GA-BP) model are 0.747, 0.748, and 0.785, respectively, indicating that the method can be effectively applied to evaluate drifting snow susceptibility.

Risk assessment method for industrial accident consequences and human vulnerability in urban areas

The rapid development of chemistry in the past years has caused not only serious environmental pollution but also other disastrous accidents to certain local areas, especially those densely populated areas. Therefore, to prevent the disastrous consequences of those accidents on vulnerable areas effectively, the local government should determine the sensibility of different regions to potential risks. An integrated risk assessment procedure, which considers accident consequences and the vulnerability of local population, is presented and then applied to a small town in China. In this procedure, a hazard map is obtained from the footprint of regional hazards. The population vulnerability is determined on the basis of the exposure, sensitivity, and adaptability of residents. Population exposure indicators include population density and dwelling environment. Population sensitivity indicators consist of health status, gender, age, and educational level. Adaptability indicators include emergency supplies, medical resources, and traffic convenience. The ArcGIS mapping software is used to overlay the hazard map and the population vulnerability map to generate a composite risk map. The synthesized human vulnerability index system in combination with regional features, overlapping with possible accident ranges, clarifies the visualization of regional risks. This regional risk map can assess the existing land utilization condition; provide a reference for future land planning, transportation line improvement, and medical service configuration; and benefit emergency plan design and material input.

Beam dynamics simulation study for longitudinal bunch length measurement of RF modulated thermionic electron gun at VECC, Kolkata

A superconducting electron linac (e-linac) photo-fission driver is under construction at VECC for the upcoming rare isotope beam facility called ANURIB. Electron gun and straight low energy beam transport (LEBT) line has been installed and is operational at a test area, delivering electron beam of 100 keV. We discuss beam dynamics and analytical calculations leading to optimal parameters of analysing section of LEBT line and RF deflector cavity that will be used for measuring longitudinal characteristics for the low energy electron beam.

Specific Features of Building Transport Infrastructure in Megacities

The paper analyzes specific features of the transport infrastructure building in modern megacities. Recently, the issues of transport infrastructure built in many megacities and cities associated with the comprehensive solution to urban and transport problems have become noticeably more relevant. This study uses a systemic approach that helped to show continuity, scale and social orientation of the transport infrastructure in megacities. The main problems and achievements in solving transport problems in large cities are identified. The issue of the role and importance of better transport infrastructure development in megacities is considered through the prism of complex and sometimes conflicting relations between transport and environment. The current transport infrastructure challenges and problems, new opportunities and benchmarks in achieving maximum efficiency of a particular mode of transport under different conditions are indicated. Special focus is placed on the possibilities of providing convenient and shortest travelling routes between all parts of the city, as well as between external transport routes. The content of the city transport network is described and characterized consisting of a set of streets and traffic routes served by various forms of city transport, underground, ground, above-ground transport lines connected with the street network in part or not connected with it at all, for example, city railways, overhead roads, metro, monorail roads.

New Design and Optimization of a Jet Pump to Boost Heavy Oil Production

In the Oil and Gas industry, installing pipe loops is a well-known hydraulic practice to increase oil pipeline capacities. Nevertheless, pipe loops could promote an unfavorable phenomenon known as fouling. That means that in a heavy oil-water mixture gathering system with low flow velocities, an oil-water stratified flow pattern will appear. In consequence, due to high viscosity, the oil stick on the pipe, causing a reduction of the effective diameter, reducing handled fluids production, and increasing energy consumption. As jet pumps increase total handled flow, increase the fluid velocities, and promote the homogenous mixture of oil and water, this type of pump could result attractive compared to other multiphase pump systems in reactivating heavy crude oil transport lines. Jet pumps are highly reliable, robust equipment with modest maintenance, ideal for many applications, mainly in the oil and gas industry. Nevertheless, their design method and performance analysis are rarely known in the literature and keep a high experimental component similar to most pumping equipment. This paper proposes a numerical study and the optimization of a booster multiphase jet pump system installed in a heavy oil conventional loop of a gathering system. First, the optimization of a traditionally designed jet pump, combining CFD simulation and optimization algorithms using commercials software (ANSYS CFX® and PIPEIT® tool), has been carried out. This method allowed evaluating the effect of multiple geometrical and operational variables that influence the global performance of the pump to run more than 400 geometries automatically in a reduced time frame. The optimized pump offers a substantial improvement over the original concerning total flow capacity (+17%), energy, and flow distribution. Then, the effect of the three jet pump plugin configurations in a heavy oil conventional trunkline loop was analyzed. Simulations were carried out for different driving fluid pressures and compared against a traditional pipeline loop’s performance. Optimum plugin connection increases fluid production by 30%. Finally, a new eccentric jet pump geometry has been proposed to improve exit velocities and pressure fields. This eccentric jet pump with the best connection was analyzed over the same conditions as the concentric optimized one. An improvement of 2% on handled fluid was achieved consistently with the observed uniform velocity field at the exit of the pump. A better total fluid distribution between the main and the loop line is obtained, handling around half of the complete fluid each.

A Review of Modelling of the FCC Unit—Part II: The Regenerator

Heavy petroleum industries, including the Fluid Catalytic Cracking (FCC) unit, are among some of the biggest contributors to global greenhouse gas (GHG) emissions. The FCC unit’s regenerator is where these emissions originate mostly, meaning the operation of FCC regenerators has come under scrutiny in recent years due to the global mitigation efforts against climate change, affecting both current operations and the future of the FCC unit. As a result, it is more important than ever to develop models that are accurate and reliable at predicting emissions of various greenhouse gases to keep up with new reporting guidelines that will help optimise the unit for increased coke conversion and lower operating costs. Part 1 of this paper was dedicated to reviewing the riser section of the FCC unit. Part 2 reviews traditional modelling methodologies used in modelling and simulating the FCC regenerator. Hydrodynamics and kinetics of the regenerator are discussed in terms of experimental data and modelling. Modelling of constitutive parts that are important to the FCC unit, such as gas–solid cyclones and catalyst transport lines, are also considered. This review then identifies areas where the current generation of models of the regenerator can be improved for the future. Parts 1 and 2 are such that a comprehensive review of the literature on modelling the FCC unit is presented, showing the guidance and framework followed in building models for the unit.

Investigation of Changes in Flow Parameters along the Transport Line in Installations for Pneumatic Transport of Cotton

The article presents the results of a study of changes in the parameters of the flow, velocity and pressure of air along the cotton transportation line in pneumatic transport installations and their dependence on the parameters of the pipeline. The purpose of the research is to theoretically substantiate the choice of the pipeline diameter depending on the properties of the material (cotton), the required processing capacity and pipeline throughput. In the research, an analytical method was used to study changes in the pressure of the air flow along the transportation line at different pipeline diameters. It is established that, according to the existing calculation method, the flow pressure along the transportation line is reduced to zero. At the same time, various scientists have proposed various analytical and empirical dependencies, which, in turn, give different ideas about the resistance of the inner surface of the pipes to the movement of air and material flow and do not describe the real situation, especially when transporting material from a long distance. This requires in-depth theoretical and applied research to establish real patterns of changes in flow parameters along the material (cotton) transportation line.

About the Change in Air Pressure in the Pipeline during the Pneumatic Transportation of Cotton

The article is devoted to the study of the issues of determining the patterns of changes in air pressure along the length of a pneumatic transmission pipeline for raw cotton at different flow parameters and different pipeline diameters. Theoretical studies have proved the reduction of static and total pressure along the line of pneumatic cotton transportation. The dependence of the pressure change on the diameter of the transport line and the aerodynamic drag of the pipeline is obtained. The results obtained are recommended for use in the design of raw cotton pneumatic transport systems.

Public transport travel mode chain and its implications for commute satisfaction: Take Xi'an as an example

The continuous expansion of urban population and space scale, the continuous increase of daily average traffic trips and per capita travel distance, and the increasingly frequent urban economic activities have formed diversified travel demands. Based on the survey data, this study combs the commuter travel mode chain of Xi'an with public transport as the main body, and explores the satisfaction of current commuter bus passengers. First of all, the impact factors of each link of the public transport travel mode chain are sorted out. Based on the three levels of reachability, accessibility and connectivity, this paper proposes an evaluation index system of urban public transport commuting service, including convenience, safety, comfort, reliability and other specific indicators. Secondly, the commuting satisfaction evaluation scale is constructed to evaluate the subjective experience of travellers in the travel process. The results show that there is a gap between the expectation of commuters and the perception of public transport service attributes. Among them, "convenience" and "comfort" of public transport are the most important service quality attributes related to the satisfaction of commuters, and residents are the least satisfied with the convenience of transit, and public transport lines fail to meet the commuting needs of some residents. When transport operators provide services that meet passengers' expectations, passenger satisfaction and PBT utilization rate will be improved, service quality of public transport mode chain will be improved, sustainable transport will be promoted, and energy consumption and emissions will be reduced.

Methodology for public transport mode detection using telecom big data sets: case study in Croatia

Determining the number of passengers using public transport services is a challenging and time-consuming task that relies either on manual observations (e.g. manual counting passengers in vehicles or at stations) or the application of technical solutions (using data from automatic fare collection system (AFC) or automatic passenger counters (APC), which is characterized either by the provision of an incomplete picture (AFC) or by a solution which in practice is installed in a small number of vehicles if any (APC). The new approach which uses anonymized telecom-originated big data sets and data science principles can be used as a smart data driven approach for determining the use of public transport. Anonymized telecom big data sets represent “digital breadcrumbs” that people leave while moving through the city. When paired with additional data sets (e.g. public transport timetables, location of public transport stations, information on public transport lines, etc.), it can be used for modal split detection. In this paper, a new methodological approach is proposed that uses anonymized telecom big data sets and a statistical modelling approach to identify possible public transport trips among all other trips. This methodology has been tested in a case study in the City of Rijeka and validated using ground truth data obtained from traditional sources.

Demand Estimation of Proposed Bus Rapid Route in Al Kut City

Public transit in the city of Al-Kut faces great challenges due to the weakness of the local government abilities in providing adequate conditions for public transport such as wide vehicles, comfortable seats, and other environmentally friendly means of transport that are almost non-use in the city of Kut, where the dependence is heavily on Mini Bus (Kia) and a medium-sized bus, most of which are old, do not operate in an integrated way, compete with each other for the passengers, reduce the flexibility of movement. This study attempts to estimate the demand for the proposed bus rapid route in the city of al Kut as a modern public transport that can contribute to reducing congestion in the city. In this study, the demand for the current public transport network lines in the city was studied, which are 12 lines using boarding / alighting values to determine passenger loads and assess flow on each route in the transportation network using the origin-destination (OD) data from on/off data, then repeat the application on the BRT route, this was done using assignment model in TransCAD software, where the results showed an estimated value for passenger demand on BRT route about 7,616 passengers/hour, which is equivalent to 40.12 % of the transport lines service.

The application of neural networks for the life-cycle analysis of road and rail rolling stock during the operational phase

The aim of this article is to assess the possibility of using neural networks to analyse the life cycle of rolling stock in the operational phase by selecting the number of rolling stock sets and rail using the example of public transport in the Szczecin agglomeration. The research was conducted in September 2019 and June 2020. It included the number of tram and bus rolling stock sets on individual public transport lines based on data from the Central Public Transport Management System in the Szczecin agglomeration. The research, which was based on comparative analyses of individual types of rolling stock and their technical and economic data, took into account the life-cycle assessment criteria associated with the operation of vehicles in relation to the number of rolling stock sets. The use of neural networks on the example of the city of Szczecin for the purpose of life-cycle analysis, can make a significant contribution to creating a decision model for the improvement of public transport in cities with various types of public transport vehicles.

Coordinating feeder and collector public transit lines for efficient MaaS services

Coordinating the schedules of feeder and collector public transit lines can reduce the passenger travel times. With advances in smart mobility, mobility-as-a-service (MaaS) schemes allow passengers to book a combined ticket for all their trip legs. This detailed information about the origins and destinations of door-to-door trips offers the opportunity to coordinate the schedules of public transport lines to reduce the passenger travel times. In this study, we model the coordination problem of feeder and collector lines by explicitly considering the regularity of the feeder lines and the transfer times of passengers. The coordination problem is modeled as a nonlinear non-convex problem and reformulated to an easy-to-solve convex optimization problem. Because of the travel times uncertainty, we also introduce a stochastic optimization formulation based on the sample average approximation approach. We test the performance of our approach in a case study with feeder and collector lines in Singapore showing an improvement potential of 5%–10% in passenger travel times. • A novel, easy-to-solve model for the coordination of feeder and collector transit lines. • Explicit consideration of door-to-door travel times for efficient MaaS services. • Improvement potential of 5%–10% even under uncertain demand conditions.

Automatic Detection of Track Length Defects

Abstract Ensuring the safety of railway transport operation requires constant monitoring of the technical condition of individual elements of railway infrastructure. The necessary activities that contribute to maintaining good operational condition of the railway transport line also include the diagnostics of track length. Diagnostics of railway tracks is most often performed by means of regular visual inspection (in the conditions of the infrastructure manager – ŽSR). The objective of the article is to provide information on the application of a new approach to diagnostics of the technical condition of railway infrastructure. The new approach to defect identification on railway infrastructure uses non-invasive diagnostic methods based on the latest knowledge in the field of information and communication technologies. These facts resulted in investigating the possibilities of automatic detection of the technical condition of the track length using neural networks. The article is part of the following scientific research task: ‘Research into new knowledge and observational experience of a new generation of diagnostic systems in industrial production and transport industry – research into the physical nature of an automated track length video inspection system’, supported by the Ministry of Education, Science, Research and Sport of the Slovak Republic.

Mixed Fuzzy-Logic and Game-Theoretical Approach to Justify Vehicle Models for Servicing the Public Bus Line

One of the main problems to be solved by the transport operators is the substantiation of the vehicle models servicing the transport lines. A gametheoretical approach is proposed in this paper to justify the bus model choice based on the passengers’ preferences and the structure of the passenger flows. To estimate the customers’ preferences, the membership functions for fuzzy sets of the optimal vehicle models were defined. The simulation experiment aiming to estimate the city fleet structure in terms of the vehicles’ capacity was conducted for the Talas city (Kazakhstan) based on the proposed approach with use of the corresponding software implementation of the developed mathematical models. As a result of the experimental studies, the impact of the passengers’ flow structure and the number of carriers on the rational structure of the city bus fleet was studied in the paper.

Inclusion of DLVO forces in simulations of non-Brownian solid suspensions: Rheology and structure

The understanding of the rheological behaviour of suspensions in aqueous electrolytes is necessary for the optimal design of hydraulic transport lines. In these applications, particle size is at least 10 micron, and the particle Reynolds number, Rep, is finite: O(10−1). Although there are some experimental and numerical data on the rheology of such suspensions, the number of detailed analyses is limited. Therefore, 3-D direct numerical simulations of dense suspensions in aqueous electrolytes are conducted to assess the dynamics of the relative apparent viscosity and particle structures. The solid–liquid interfaces are resolved, and the flow is simulated, employing an in-house immersed boundary-lattice Boltzmann method code. In addition to the hydrodynamics resolved in the computational grid, our simulations include unresolved sub-grid scale lubrication corrections and non-contact electric double layer (EDL) and Van der Waals forces for a wide range of particle volume fractions, ϕv, at a single Rep=0.1. Under these conditions, the contribution of the Van der Waals force was found to be weak. With an increase in ϕv, the effect of EDL forces decreased the relative apparent viscosity. Particle layering and structural arrangements were analysed for ϕv=43 and 52%. As the Debye length (i.e., the thickness of EDL) decreases, the particle layers near the walls weakened. The analyses reveal how at these high volume fractions, chain-like assemblies are transformed into hexagonal arrangements.

Life Cycle Assessment of Cross-Laminated Timber Transportation from Three Origin Points

Cross-laminated timber (CLT) used in the U.S. is mainly imported from abroad. In the existing literature, however, there are data on domestic transportation, but little understanding exists about the environmental impacts from the CLT import. Most studies use travel distances to the site based on domestic supply origins. The new Adohi Hall building at the University of Arkansas campus, Fayetteville, AR, presents the opportunity to address the multimodal transportation with overseas origin, and to use real data gathered from transporters and manufacturers. The comparison targets the environmental impacts of CLT from an overseas transportation route (Austria-Fayetteville, AR) to two other local transportation lines. The global warming potential (GWP) impact, from various transportation systems, constitutes the assessment metric. The findings demonstrate that transportation by water results in the least greenhouse gas (GHG) emission compared with freight transportation by rail and road. Transportation by rail is the second most efficient, and by road the least environmentally efficient. On the other hand, the comparison of the life cycle assessment (LCA) tools, SimaPro (Ecoinvent database) and Tally (GaBi database), used in this research, indicate a remarkable difference in GWP characterization impact factors per tonne.km (tkm), primarily due to the different database used by each software.