Search results for: transport by ship

Authors: Sajith Sajeev, Brenton McLaury, Siamack Shirazi

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In the petroleum industry, solid particles are often present along with the produced fluids. It is imperative to keep particles from accumulating in flow lines. In this study, various experiments are conducted to study sand particle transport, where critical velocity is defined as the average fluid velocity to keep particles continuously moving. Many parameters related to the fluid, particles and pipe affect the transport process. Experimental results are presented varying the particle concentration. Additionally, CFD simulations using a discrete element modeling (DEM) approach are presented to compare with experimental result.

Keywords: particle transport, critical velocity, CFD, DEM

Procedia PDF Downloads 285

Authors: Siu Hua Chang, Ayub Md Som, Jagannathan Krishnan

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The kinetics of Cu(II) transport through a bulk liquid membrane with different membrane materials was investigated in this work. Three types of membrane materials were used: Fresh cooking oil, waste cooking oil, and kerosene each of which was mixed with di-2-ethylhexylphosphoric acid (carrier) and tributylphosphate (modifier). Kinetic models derived from the kinetic laws of two consecutive irreversible first-order reactions were used to study the facilitated transport of Cu(II) across the source, membrane, and receiving phases of bulk liquid membrane. It was found that the transport kinetics of Cu(II) across the source phase was not affected by different types of membrane materials but decreased considerably when the membrane materials changed from kerosene, waste cooking oil to fresh cooking oil. The rate constants of Cu(II) removal and recovery processes through the bulk liquid membrane were also determined.

Keywords: transport kinetics, Cu(II), bulk liquid membrane, waste cooking oil

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Authors: Grzegorz Sierpiński, Ireneusz Celiński, Marcin Staniek

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The article discusses multi modal mobility in contemporary societies as a main planning and organization issue in the functioning of administrative bodies, a problem which really exists in the space of contemporary cities in terms of shaping modern transport systems. The article presents classification of available resources and initiatives undertaken for developing multi modal mobility. Solutions can be divided into three groups of measures–physical measures in the form of changes of the transport network infrastructure, organizational ones (including transport policy) and information measures. The latter ones include in particular direct support for people travelling in the transport network by providing information about ways of using available means of transport. A special measure contributing to this end is a trip planner. The article compares several selected planners. It includes a short description of the Green Travelling Project, which aims at developing a planner supporting environmentally friendly solutions in terms of transport network operation. The article summarizes preliminary findings of the project.

Keywords: mobility, modal split, multimodal trip, multimodal platforms, sustainable transport

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Authors: Anu S. Nair, V. Anantha Subramanian

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This paper presents a surface development and fairing technique combining the features of a modern computer-aided design tool namely the Non-Uniform Rational Basis Spline (NURBS) with an algorithm to obtain a rapidly faired hull form. Some of the older series based designs give sectional area distribution such as in the Wageningen-Lap Series. Others such as the FORMDATA give more comprehensive offset data points. Nevertheless, this basic data still requires fairing to obtain an acceptable faired hull form. This method uses the input of sectional area distribution as an example and arrives at the faired form. Characteristic section shapes define any general ship hull form in the entrance, parallel mid-body and run regions. The method defines a minimum of control points at each section and using the Golden search method or the bisection method; the section shape converges to the one with the prescribed sectional area with a minimized error in the area fit. The section shapes combine into evolving the faired surface by NURBS and typically takes 20 iterations. The advantage of the method is that it is fast, robust and evolves the faired hull form through minimal iterations. The curvature criterion check for the hull lines shows the evolution of the smooth faired surface. The method is applicable to hull form from any parent series and the evolved form can be evaluated for hydrodynamic performance as is done in more modern design practice. The method can handle complex shape such as that of the bulbous bow. Surface patches developed fit together at their common boundaries with curvature continuity and fairness check. The development is coded in MATLAB and the example illustrates the development of the method. The most important advantage is quick time, the rapid iterative fairing of the hull form.

Keywords: computer-aided design, methodical series, NURBS, ship design

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Authors: Eva Nedeliakova, Jaroslav Masek, Juraj Camaj

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This article describes the results of research focused on quality of railway freight transport services. Improvement of these services has a crucial importance in customer considering on the future use of railway transport. Processes filling the customer demands and output quality assessment were defined as a part of the research. In this, contribution is introduced the map of quality planning and the algorithm of applied methodology. It characterises a model which takes into account characters of transportation with linking a perception services quality in ordinary and extraordinary operation. Despite the fact that rail freight transport has its solid position in the transport market, lots of carriers worldwide have been experiencing a stagnation for a couple of years. Therefore, specific results of the research have a significant importance and belong to numerous initiatives aimed to develop and support railway transport not only by creating a single railway area or reducing noise but also by promoting railway services. This contribution is focused also on the application of dynamic quality models which represent an innovative method of evaluation quality services. Through this conception, time factor, expected and perceived quality in each moment of the transportation process can be taken into account.

Keywords: quality, railway, transport, service

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Authors: V. Yu. Shungin, A. V. Popov

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At present, one of the main tasks of Russian shipbuilding yards is implementation of new technologies and replacement of main process equipment. In particular, conventional bending technologies with dies are being replaced with resource-saving methods of rotation (roller) banding. Such rolling bending is performed by multiple rolling of a plat in special bending rollers. Studies, conducted in JSC SSTC, allowed developing a theory of rotation bending, methods for calculation of process parameters, requirements to roller presses and bending accessories. This technology allows replacing old and expensive presses with new cheaper roller ones, having less power consumption and bending force. At first, roller presses were implemented in ship repair, however now they are widely employed at major shipbuilding yards. JSC SSTC develops bending technology and carries out design, manufacturing and delivery of roller presses.

Keywords: bending/straightening machines, rotational bending, ship hull structures, multifunctional bending

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Authors: Lobna Ahmed Galal

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Modal integration has given minimal consideration in cities of developing countries, as well as the declining dominance of public transport, and predominance of informal transport, the modal share of informal taxis in greater Cairo has increased from 6% in 1987 to 37% in 2001 and this has since risen even higher, informal and non-motorized modes of transport acting as a gap filler by feeding other modes of transport, not by design or choice, but often by lack of accessible and affordable public transport. Yet non-motorized transport is peripheral, with minimal priority in urban planning and investments, lacking of strong polices to support non-motorized transport, for authorities development is associated with technology and motorized transport, and promotion of non-motorized transport may be considered corresponding to development, as well as social stigma against non-motorized transport, as it is seen a travel mode for the poor. Cairo as a city of a developing country, has poor quality infrastructure for non-motorized transport, suffering from absence of dedicated corridors, and when existing they are often encroached for commercial purposes, widening traffic lanes at the expense of sidewalks, absence of footpaths, or being overcrowded, poor lighting, making walking unsafe and yet, lack of financial supply to such facilities as it is often considered beyond city capabilities. This paper will deal with the objective measuring of the built environment relating to walking, in some neighborhoods of new cities around Cairo, In addition to comparing the results of the objective measures of the built environment with the level of self-reported survey. The first paper's objective is to show how the index ‘walkability of community neighborhoods’ works in the contexts in neighborhoods of new cities around Cairo. The procedure of objective measuring is of a high potential to be carried out by using GIS.

Keywords: assessing, built environment, Cairo, walkability

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Authors: Hyungsuk Han, Soohong Jeon, Chungwon Lee, YongHoon Kim

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When a rubber mount and flexible coupling are installed on the main engine, high torsional vibration can occur. The root cause of this high torsional vibration can be attributed to the lateral-torsional coupled vibration of the shaft system. Therefore, the lateral-torsional coupled vibration is investigated numerically after approximating the shaft system to a three-degrees-of-freedom Jeffcott rotor. To verify that the high torsional vibration is caused by the lateral-torsional coupled vibration, a test unit that can simulate this lateral-torsional coupled vibration occurring in the propulsion shaft is developed. Performing a vibration test with the test unit, it can be experimentally verified that the high torsional vibration occurring in the propulsion shaft of the particular ship was caused by the lateral-torsional coupled vibration.

Keywords: Jeffcott rotor, lateral-torsional coupled vibration, propulsion shaft, stability

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Authors: Nadjet Brahmia

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The growing needs of displacements led advanced countries in this field install new specific transport systems, able to palliate any deficiencies, especially when regular public transport does not adequately meet the requests of users. In this context, on-demand transportation (ODT) are very efficient; they rely on techniques based on the location of trip generators which should be assured effectively with the use of operators responsible of the advance reservation, planning and organization, and studying the different ODT criteria (organizational, technical, geographical, etc.). As the advanced countries in the field of transport, some developing countries are involved in the adaptation of the new technologies to reduce the deficit in their communication system. This communication presents the study of an ODT implementation in the west of Algeria, by developing the Geomatics side of the study. This part requires the use of specific systems (such as GIS, RDBMS…), so we developed the process through an application in an environment of mobility by using the computer tools dedicated to the management of the entities related to the transport field.

Keywords: ODT, geomatics, GIS, transport systems

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Authors: Sungjun Hong, Yanghon Chung, Nyunbae Park, Sangyong Park

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South Korea, as the 7th largest greenhouse gas emitting country in 2011, announced that the national reduction target of greenhouse gas emissions was 30% based on BAU (Business As Usual) by 2020. And the reduction rate of the transport sector is 34.3% which is the highest figure among all sectors. This paper attempts to analyze the environmental effect on deploying the green cars in Korean road transport sector. In order to calculate the greenhouse gas emissions, the LEAP model is applied in this study.

Keywords: green car, greenhouse gas, LEAP model, road transport sector

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Authors: Dina A. Amu, Fifi N. Afifah, Catur Rosidati, Tirton Nefianto

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Indonesia was shaken up by the avian influenza cases that had caused the country suffered losses of millions of dollars. The avian influenza case had even been suspected as a bioterrorism attack since it was an uncommon case in epidemiology. Furthermore, this avian influenza virus is a high pathogenic one and Indonesia has the highest case of fatality rate in the world. Bioterrorism threats or epidemic potential disease outbreaks currently does not exist in Tanjung Priok port yet. However, the surveillance system enhancement on epidemic potential diseases should be taken as a prevention, especially because Indonesia is currently facing the ASEAN Economic Society (AES). Therefore, this research evaluates the health surveillance system which is organized by Control, Quarantine and Surveillance Department, Health Office of Tanjung Priok Port. This study uses qualitative-evaluative method which utilizes Urgency Seriousness Growth (USG) method to determine priority issues and Root Cause analysis to determine the cause of prior problem. The result of this research shows that the implementation of epidemic potential disease surveillance in Tanjung Priok port has not done in the best possible way. It is because the lack of time allocation and the succinctness of the check list of ship's environmental health inspection. Therefore, Health Ministry of Indonesia should recruit more employees at the health office of Tanjung Priok port, hold a simulation of ship's inspection and simplify the list for ship's environmental health inspection.

Keywords: surveillance, epidemic potential disease, port health, bioterrorism

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Authors: Pedro Pablo Ramírez Sánchez, Alassane Ballé Ndiaye, Roberto Rendeiro Martín-Cejas

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The aim of this paper is to analyse the different environmental policies adopted in Europe for car emissions, to comment on some of the possible perverse effects generated and point out these policies which are considered more efficient under the environmental perspective. This paper is focused on passenger cars as this category is the most significant in road transport. The utility of this research lies in this being the first step or basis to improve and optimise actual policies. The methodology applied in this paper refers to a comparative analysis from a practical and theoretical point of view of European environmental policies in road transport. This work describes an overview of the road transport industry in Europe pointing out some relevant aspects such as the contribution of road transport to total emissions and the vehicle fleet in Europe. Additionally, we propose a brief practice guide with the combined policies in order to optimise their aim.

Keywords: air quality, climate change, emission, environment, perverse effect, road transport, tax policy

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Authors: R. Testoni, R. Levizzari, M. De Salve

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Radioactive waste management is fundamental to safeguard population and environment by radiological risks. Environmental assessment of a site, where nuclear activities are located, allows understanding the hydro geological system and the radionuclides transport in groundwater and subsoil. Use of dedicated software is the basis of transport phenomena investigation and for dynamic scenarios prediction; this permits to understand the evolution of accidental contamination events, but at the same time the potentiality of the software itself can be verified. The aim of this paper is to perform a numerical analysis by means of HYDRUS 1D code, so as to evaluate radionuclides transport in a nuclear site in Piedmont region (Italy). In particular, the behaviour in vadose zone was investigated. An iterative assessment process was performed for risk assessment of radioactive contamination. The analysis therein developed considers the following aspects: i) hydro geological site characterization; ii) individuation of the main intrinsic and external site factors influencing water flow and radionuclides transport phenomena; iii) software potential for radionuclides leakage simulation purposes.

Keywords: HYDRUS 1D, radionuclides transport phenomena, site characterization, radiation protection

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Authors: Gunnar Oskarsson, Irena Georgsdottir

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Tourism has been growing incredibly fast during the past years, including the cruise industry, which is gaining increasing popularity among various groups of travelers. It is a challenging task for companies serving cruise ship passengers with local products and services at the point of destination to reach them in due time with information about their offerings, as well learning how to adapt their offerings and messages to the type of customers arriving on each particular occasion. Although some research has been conducted in this sphere, there is still limited knowledge about many specifics within this sector of the tourist industry. The objective of this research is to examine one of these, with the main goal of studying the segmentation of cruise passengers and to learn about marketing practices directed towards them. A qualitative research method, based on in-depth interviews, was used, as this provides an opportunity to gain insight into the participants’ perspectives. Interviews were conducted with 10 respondents from different companies in the tourist industry in Iceland, who interact with cruise passengers on a regular basis in their work environment. The main objective was to gain an understanding of what distinguishes different customer groups, or segments, in this industry, and of the marketing approaches directed towards them. The main findings reveal that participants note the strongest difference between cruise passengers of different nationalities, passengers coming on different ships (size and type), and passengers arriving at different times of the year. A drastic difference was noticed between nationalities in four main segments, American, British, Other European, and Asian customers, although some of these segments could be divided into even further sub-segments. Other important differencing factors were size and type of ships, quality or number of stars on the ship, and travelling time of the year. Companies serving cruise ship passengers, as well as the customers themselves, could benefit if the offerings of services were designed specifically for particular segments within the industry. Concerning marketing towards cruise passengers, the results indicate that it is carried out almost exclusively through the Internet using; a reliable website and, search engine optimization. Marketing is also by word-of-mouth. This research can assist practitioners by offering a deeper understanding of the approaches that may be effective in marketing local products and services to cruise ship passengers, based on their segmentation and by identifying effective ways to reach them. The research, furthermore, provides a valuable contribution to marketing knowledge for the benefit of an increasingly important market segment in a fast growing tourist industry.

Keywords: capabilities, global integration, internationalisation, SMEs

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Authors: Ayudhia P. Gusti, Semin

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It is known that total operating cost of a vessel is dominated by the cost of fuel consumption. How to reduce the fuel cost of ship so that the operational costs of fuel can be minimized is the question that arises. As the basis of these kinds of problem, sailing speed determination is an important factor to be considered by a shipping company. Optimal speed determination will give a significant influence on the route and berth schedule of ships, which also affect vessel operating costs. The purpose of this paper is to clarify some important issues about ship speed optimization. Sailing speed, displacement, sailing time, and specific fuel consumption were obtained from shipping log data to be further analyzed for modeling the speed optimization. The presented speed optimization model is expected to affect the fuel consumption and to reduce the cost of fuel consumption.

Keywords: maritime transportation, reducing fuel, shipping log data, speed optimization

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Authors: Evangelia Gaitanidou, Evangelos Bekiaris

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Considering that resilience implies the ability of a system to adapt continuously in order to respond to its operational goals, a system is considered as more or less resilient depending on the level and time of recovering from disruptive events and/or shocks to its initial state. Regarding transport systems, enhancing resilience is considered imperative for two main reasons: Such systems provide critical support to every socio-economic activity, while being one of the most important economic sectors and, secondly, the paths that convey people, goods and information, are the same through which risks are propagated. RESOLUTE (RESilience management guidelines and Operationalization appLied to Urban Transport Environment) Horizon 2020 research project is answering those needs, by proposing and testing a set of guidelines for resilience management of the urban transport system. The methods and steps towards this goal, through a step-wise methodology, taking into account established models like FRAM (Functional Resonance Analysis Model), and upon gathering existing practices are described in this paper, together with an overview of the produced guidelines. The overall aim is to create a framework which public transport authorities could consult and apply, for rendering their infrastructure resilient against natural disaster and other threats.

Keywords: guidelines, infrastructure, resilience, transport

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Authors: Paola Quintana, Angélica Vaca, Sebastián Villacres, Henry Acurio

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Ecuador through the Organic Law of Energy Efficiency establishes that "Starting in the year 2025, all vehicles that are incorporated into the urban and inter-parroquial public transport service must only be electric”, this marks a foundation for the introduction of electric mobility in the country. The present investigation is based on developing an analysis and projection of the Energy Required for the incorporation of electric buses for public passenger transport in the city of Ambato-Ecuador, taking into account the useful life of the vehicle fleet, number of existing vehicles and analysis of transport routes in the study city. The energy demand based on the vehicular dynamics is analyzed, determination of equations for the calculation of force in the wheel since it is considered a variable of slope due to the fact that this has a great incidence in the autonomy when speaking of electric mobility, later the energy analysis applied to public transport routes, finally a projection of the energy requirement is made based on the change of public transport units according to their useful life.

Keywords: public transport, electric mobility, energy, ecuador

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Authors: Mehmet Yahsi, Ozkan Ugurlu

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Cabin department among the stewards and cooks on ships, has an important place in terms of a sufficient and qualified nutrition of seafarers. From this perspective, ships must be employed with a sufficient number of cabin department. In this study, in order to research on the Turkish-flagged ships cook and stewards employment; Our national manning regulation compared with international regulations. The data used in this study were collected via visiting of the ships. 3000 gross tonnage and above engaged in international voyages 181 Turkish-flagged ship’s crew lists were compared with Minimum Safety Manning Certificates. According to the findings; employment rates, %95,6 cook, and %50,8 steward. According to the results of the study; Turkish-flagged ships, although it is not obliged to cook and steward, were employed on ships.

Keywords: manning, cabin department, minimum safety manning certificate, Turkish flag

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Authors: Tanmay Bisen, Aastha Shayla, Susham Biswas

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Oil spills from tankers can cause significant harm to the environment and local communities, as well as have economic consequences. Early predictions of oil spills can help to minimize these impacts. Our proposed system uses machine learning and neural networks to predict potential oil spills by monitoring data from ship Automatic Identification Systems (AIS). The model analyzes ship movements, speeds, and changes in direction to identify patterns that deviate from the norm and could indicate a potential spill. Our approach not only identifies anomalies but also predicts spills before they occur, providing early detection and mitigation measures. This can prevent or minimize damage to the reputation of the company responsible and the country where the spill takes place. The model's performance on the MV Wakashio oil spill provides insight into its ability to detect and respond to real-world oil spills, highlighting areas for improvement and further research.

Keywords: Anomaly Detection, Oil Spill Prediction, Machine Learning, Image Processing, Graph Neural Network (GNN)

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Authors: N. R. Badurally Adam, S. R. Monebhurrun, M. Z. Dauhoo, A. Khoodaruth

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Transport energy demand is vital for the economic growth of any country. Globalisation and better standard of living plays an important role in transport energy demand. Recently, transport energy demand in Mauritius has increased significantly, thus leading to an abuse of natural resources and thereby contributing to global warming. Forecasting the transport energy demand is therefore important for controlling and managing the demand. In this paper, we develop a model to predict the transport energy demand. The model developed is based on a system of five stochastic differential equations (SDEs) consisting of five endogenous variables: fuel price, population, gross domestic product (GDP), number of vehicles and transport energy demand and three exogenous parameters: crude birth rate, crude death rate and labour force. An interval of seven years is used to avoid any falsification of result since Mauritius is a developing country. Data available for Mauritius from year 2003 up to 2009 are used to obtain the values of design variables by applying genetic algorithm. The model is verified and validated for 2010 to 2012 by substituting the values of coefficients obtained by GA in the model and using particle swarm optimisation (PSO) to predict the values of the exogenous parameters. This model will help to control the transport energy demand in Mauritius which will in turn foster Mauritius towards a pollution-free country and decrease our dependence on fossil fuels.

Keywords: genetic algorithm, modeling, particle swarm optimization, stochastic differential equations, transport energy demand

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Authors: Jinliang Yuan, Jong-Sung Yu, Bengt Sundén

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A computational fluid dynamics (CFD) model is developed for rechargeable non-aqueous electrolyte lithium-air batteries with a partial opening for oxygen supply to the cathode. Multi-phase transport phenomena occurred in the battery are considered, including dissolved lithium ions and oxygen gas in the liquid electrolyte, solid-phase electron transfer in the porous functional materials and liquid-phase charge transport in the electrolyte. These transport processes are coupled with the electrochemical reactions at the active surfaces, and effects of discharge reaction-generated solid Li2O2 on the transport properties and the electrochemical reaction rate are evaluated and implemented in the model. The predicted results are discussed and analyzed in terms of the spatial and transient distribution of various parameters, such as local oxygen concentration, reaction rate, variable solid Li2O2 volume fraction and porosity, as well as the effective diffusion coefficients. It is found that the effect of the solid Li2O2 product deposited at the solid active surfaces is significant on the transport phenomena and the overall battery performance.

Keywords: Computational Fluid Dynamics (CFD), modeling, multi-phase, transport phenomena, lithium-air battery

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Authors: M. Lu

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The paper presents part of the results of EU-funded projects: SoCool@EU (Sustainable Organisation between Clusters Of Optimized Logistics @ Europe), DG-RTD (Research and Innovation), Regions of Knowledge Programme (FP7-REGIONS-2011-1). It will provide an in-depth review of emerging technologies for further improving urban mobility and freight transport systems, such as (information and physical) infrastructure, ICT-based Intelligent Transport Systems (ITS), vehicles, advanced logistics, and services. Furthermore, the paper will provide an analysis of the barriers and will review business models for the market uptake of innovations. From a perspective of science and technology, the challenges of urbanization could be mainly handled through adequate (human-oriented) solutions for urban planning, sustainable energy, the water system, building design and construction, the urban transport system (both physical and information aspects), and advanced logistics and services. Implementation of solutions for these domains should be follow a highly integrated and balanced approach, a silo approach should be avoided. To develop a sustainable urban transport system (for people and goods), including inter-hubs and intra-hubs, a holistic view is needed. To achieve a sustainable transport system for people and goods (in terms of cost-effectiveness, efficiency, environment-friendliness and fulfillment of the mobility, transport and logistics needs of the society), a proper network and information infrastructure, advanced transport systems and operations, as well as ad hoc and seamless services are required. In addition, a road map for an enhanced urban transport system until 2050 will be presented. This road map aims to address the challenges of urban transport, and to provide best practices in inter-city and intra-city environments from various perspectives, including policy, traveler behaviour, economy, liability, business models, and technology.

Keywords: synchromodality, multimodal transport, logistics, Intelligent Transport Systems (ITS)

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Authors: Hamdy Ahmed Ashour

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This paper studies the parallel operation of rotary frequency converters which can be used within a ship micro-grid system and also to supply ships and equipment in a harbour during off-sail and maintenance periods with their suitable voltage and frequency requirements in order to overcome the possible associated problems of overloading on a single converter. The paper theoretically and experimentally investigated the operation of 3-ph induction motor / 3-ph synchronous generator based rotary converters set. Concept of operation and merits of such converters has been discussed. Overall dynamic simulation model of two parallel operated rotary converters has been developed. Active and reactive load sharing of the two converters has been analyzed. Experimental setup has been implemented for proof of concept and practical validation. Simulation and experimental results have been obtained and well correlated; showing how the rotary converters based setup can be manipulated to achieve different requirements of operating conditions.

Keywords: experimental, frequency-converters, load-sharing, marine-applications, simulation, synchronization

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Authors: Xiaoyu Li, Wenchuan Ding, Yujia Yia

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As the nanoscale zinc oxide particles (nano-ZnO) accumulate in the landfill, nano-ZnO will enter the landfill leachate and come into contact with the heavy metal ions in leachate, which will change their transport process in the landfill and, furthermore, affect each other's environmental fate and toxicity. In this study, we explored the transport of co-existing nano-ZnO, Cu(II) and Cr(VI) ions by column experiments under different stages of landfill leachate conditions (flow rate, pH, ionic strength, humic acid). The results show that Cu(II) inhibits the transport of nano-ZnO in the quartz sand column by increasing the surface potential of nano-ZnO, and nano-ZnO increases the retention of Cu(II) in the quartz sand column by adsorbing Cu(II) ions. Cr(VI) promotes the transport of nano-ZnO in the quartz sand column by neutralizing the surface potential of the nano-ZnO which reduces electrostatic attraction between nZnO and quartz sand, but the nano-ZnO has no effect on the transport of Cr(VI). The nature of landfill leachates such as flow rate, pH, ionic strength (IS) and humic acid (HA) has a certain effect on the transport of coexisting nano-ZnO and heavy metal ions. For leachate containing Cu(II) and Cr(VI) ions, at the initial stage of landfilling, the pH of leachate is acidic, ionic strength value is high, the humic acid concentration is low, and the transportability of nano-ZnO is weak. As the landfill age increased, the pH value in the leachate gradually increases, when the ions are raised to alkaline, these ions are trending to precipitated or adsorbed to the solid wastes in landfill, which resulting in low IS value of leachate. At the same time, more refractory organic matter gradually increases such as HA, which provides repulsive steric effects, so the nano-ZnO is more likely to migrate. Overall, the Cr(VI) can promote the transport of nano-ZnO more than Cu(II).

Keywords: heavy metal ions, landfill leachate, nano-ZnO, transport

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Authors: Jingjing Huang, Nengwei Li, Guanghua Wei, Jiabin You, Chao Wang, Junliang Zhang

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In this work, molecular dynamics (MD) simulation is applied to analyze the mass transport process in the cathode of proton exchange membrane fuel cell (PEMFC), of which all types of molecules situated in the cathode is considered. a reasonable and effective MD simulation process is provided, and models were built and compared using both Materials Studio and LAMMPS. The mass transport is one of the key issues in the study of proton exchange membrane fuel cells (PEMFCs). In this report, molecular dynamics (MD) simulation is applied to analyze the influence of Nafion ionomer distribution and Pt nano-particle size on mass transport process in the cathode. It is indicated by the diffusion coefficients calculation that a larger quantity of Nafion, as well as a higher equivalent weight (EW) value, will hinder the transport of oxygen. In addition, medium-sized Pt nano-particles (1.5~2nm) are more advantageous in terms of proton transport compared with other particle sizes (0.94~2.55nm) when the center-to-center distance between two Pt nano-particles is around 5 nm. Then mass transport channels are found to be formed between the hydrophobic backbone and the hydrophilic side chains of Nafion ionomer according to the radial distribution function (RDF) curves. And the morphology of these channels affected by the Pt size is believed to influence the transport of hydronium ions and, consequently the performance of PEMFC.

Keywords: cathode catalytic layer, mass transport, molecular dynamics, proton exchange membrane fuel cell

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Authors: Adel Belayadi, Ahmed Mougari, Boualem Bourahla

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Molecular junctions are currently considered a promising style in the miniaturization of electronic devices. In this contribution, we provide a tight-binding model to investigate the quantum transport properties across-molecular junctions sandwiched between 2D-graphene nanoribbons in the zigzag direction. We investigate, in particular, the effect of embedded atoms such as Gold and Silicon across the molecular junction. The results exhibit a resonance behavior in terms of incident Fermi levels, depending on the molecular junction type. Additionally, the transport properties under a perpendicular magnetic field exhibit an oscillation for the transmittance versus the magnetic field strength.

Keywords: molecular junction, 2D-graphene nanoribbons, quantum transport properties, magnetic field

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Authors: Mehmet Yahsi, Ozkan Ugurlu, Ercan Yuksekyildiz

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Assistant department among the electric and electronic officers on ships, has an important place for the maintenance of electric and electronic devices. From this perspective, ships must be employed with a sufficient number of assistant department. In this study, in order to research on the Turkish-flagged ships electric and electronic officers employment; Our national manning regulation compared with international regulations. The data used in this study were collected via visiting of the ships. 3000 gross tonnage and above engaged in international voyages 181 Turkish-flagged ship’s crew lists were compared with Minimum Safety Manning Certificates. According to the findings; employment rate, %54 electric and electronic officers. According to the results of the study; Turkish-flagged ships, although it is not obliged to electric and electronic officers, were employed on ships.

Keywords: manning, electric officer, electronic officer, minimum safety manning certificate

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Authors: Seyedeh Mozhgan Seyed-Talebi, Weng-Kent Chan, Hsin-Yi Tiffany Chen

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Lead-free perovskite photovoltaic (PV) technology employing non-toxic tin halide perovskite absorbers is pivotal for advancing perovskite solar cell (PSC) commercialization. Despite challenges posed by perovskite sensitivity to oxygen and humidity, our study utilizes DFT calculations using VASP and NanoDCAL software and SCAPS-1D simulations to elucidate the charge transport mechanism at the interface of CsSnI₃-FASnI₃ heterojunction. Results reveal how inherent electric fields facilitate efficient carrier transport, reducing recombination losses. We predict optimized power conversion efficiencies (PCEs) and highlight the potential of CsSnI3-FASnI3 heterojunctions for cost-effective and efficient charge transport layer-free (CTLF) photovoltaic devices. Our study provides insights into the future direction of recognizing more efficient, nontoxic heterojunction perovskite devices.

Keywords: charge transport layer free, CsSnI₃-FASnI₃ heterojunction, lead-free perovskite solar cell, tin halide perovskite., Charge transport layer free

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Authors: Jiaqi Zhang, Zhi Dong, Pan Xing

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With the continuous development of urban agglomerations, higher demands are placed on intercity public transport travel services. To improve these services, it is necessary to comprehensively understand the views and evaluations of travelers. Taking the Guanzhong Plain urban agglomeration in China as the object, this study explores subjective attitude indicators from self-administrated survey data and examines the relationship among perceived accessibility, preference, and satisfaction for intercity public transport using a structural equation model. The results show that perceived service quality has a direct positive impact on perceived accessibility and satisfaction. Perceived accessibility and preference significantly affect satisfaction. In addition, perceived accessibility mediates the effect of service quality on satisfaction. This study provides valuable insights from a policy perspective to improve the subjective evaluation of intercity public transport travelers while emphasizing the importance of subjective variables in transport system evaluation and advocates for their subdivision to more comprehensively improve the travel experience.

Keywords: intercity public transport, perceived accessibility, satisfaction, structural equation model

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Authors: Frederik Schulte, Stefan Voß

Abstract:

The adverse effects of air pollution on public health are an increasingly vital problem in planning for urban regions in many parts of the world. The issue is addressed from various angles and by distinct disciplines in research. Epidemiological studies model the relative increase of numerous diseases in response to an increment of different forms of air pollution. A significant share of air pollution in urban regions is related to transport emissions that are often measured and stored in emission inventories. Though, most approaches in transport planning, engineering, and operational design of transport activities are restricted to general emission limits for specific air pollutants and do not consider more nuanced exposure models. We conduct an extensive literature review on exposure models and emission inventories used to study the health impact of transport emissions. Furthermore, we review methods applied in both domains and use emission inventory data of transportation hubs such as ports, airports, and urban traffic for an in-depth analysis of public health impacts deploying medical exposure models. The results reveal specific urban health risks related to transport emissions that may improve urban planning for environmental health by providing insights in actual health effects instead of only referring to general emission limits.

Keywords: emission inventories, exposure models, transport emissions, urban health

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