95 research outputs found
Roll-on/roll-off terminals and truck freight : improving competitiveness in a motorways of the sea context
In recent years transport policy at an European Level has been focused on reducing the share of road transportation and promote alternative transportation means in order to reduce road congestion and carbon footprint.
One of the solutions proposed has been promoting Short Sea Shipping (SSS) transportation combined with land transportation to become a door-to-door alternative to the monomodal road alternative. The maritime centered option would hit to birds with a stone: reduce congestion in the most urbanized areas of the European Union and partly replacing heavy polluting truck haulage for an environmentally friendlier option.
The European Commission launched many polices and initiatives to make the modal shift happen, the crown jewel being the launch of multiple initiatives promoting the establishment of a system of Motorways of the Seas. Those are links between ports with higher standards in terms of travel time, costs and flexibility, which can compete one-on-one with road haulage among the countries in the Union.
Despite different efforts from the public administration to kick off MoS lines and ensure their competitiveness, the expected momentum is still yet to come.
In the light of this, this thesis aims at providing tools to assess the competitiveness of existing and MoS line to-be, to quantify the room for improvement available and the effects that some changes at an operational and strategical level might have on the success of any specific line.
Particularly, the thesis presented aims at three specific objectives: (1) to identify the strategic potential of SSS in all its forms, considering the characteristics of the demand (goods to be moved) and the role of RoRo and MoS shipping in the global picture; (2) to identify the most sensible procedures in RoRo terminals operation to be addressed to improve their performance and perception from the end user, and; (3) To understand the costs of the supply chain, and the cost structure of RoRo shipping lines, and their sensitiveness in front of market changes, pricing and public funding policies.
To approach each issue different qualitative, analytical and simulating models are used depending on the concerned problem. The strategic assessment makes use interviews to identify the main requirements that a transporter might face when dealing with SSS.
The role of the terminal is assessed by means of two separate models: from one side an analytical model is used to assess the relationship between capacity and quality by means of quantifying the service time the ship spends in a port and calculate the probability of delays. On the other side, the resilience of the port is assessed with an arborescence interlinking its current vulnerabilities, their causes and effects and their probability to happen.
Finally, and regarding the business models, first a cost and time model is constructed for each of them and tested against variations on some of the variables and from there, a tool to calculate the optimal deployment of the shipping line to ensure the maximum shift (or profit) is provided. In that case, the model is complemented with the adaptation of a transportation discrete choice model.
Overall, the tools should be helpful to assess the potential of a shipping line from its planning level to its final operational deployment.Els darrers anys, la política de transports a nivell europeu s'ha focalitzat en reduir el pes del transport per carretera de mercaderies i promoure mitjans de transport que li siguin alternatius, com a mesures per reduir la congestió a les carreteres i la petjada ecològica. Una de les solucions que s'ha posat sobre la taula, és l'anomenat Transport Marítim de Curta Distància (TMCD o SSS, en les seves sigles en anglès), com a una veritable alternativa bimodal (ferrocarril/carretera combinats amb transport marítim) a l'opció de transport monomodal per carretera. Diversos estudis certifiquen que el transport porta-a-porta transcorregut parcialment amb TMCD acostuma a registrar menors externalitats (bàsicament costos ambientals i de congestió) que el transport per carretera per cada tona transportada. Des d'un punt de vista operatiu, el TMCD i especialment la seva versió en forma d'Autopistes del Mar (AdM o MoS), enteses com a enllaços entre ports amb altes prestacions pel que fa a temps de viatge, flexibilitat i freqüència a un cost competitiu s'han estudiat àmpliament com a una alternativa directa i equivalent al transport per carretera. Però malgrat els esforços fets des de l'administració pública per promoure les línies d'AdM i assegurar-ne la competitivitat, aquestes no han obtingut l'impuls previst inicialment. L'objectiu d'aquesta tesi, de fet, és proveir un conjunt d'eines per tal d'avaluar la competitivitat de qualsevol AdM i quantificar-ne el marge de millora i l'efecte que alguns canvis a nivell operatiu i estratègic podrien tenir en la seva competitivitat , tan a nivell operatiu com estratègic, per tal de garantir-ne la competitivitat futura. De forma més específica, la tesi que aquí es presenta, analitza tres aspectes específics de les AdM: (1) Quines característiques a de tenir el seu mercat potencial a nivell estratègic, (2) con rol prenen les terminals portuàries, enteses com la baula dèbil de la cadena de transport, a nivell de la valoració qualitativa de la cadena de transport per part del seu usuari final i (3), possibles models de negoci pel transportista / propietari de la mercaderia per treure el màxim profit de les AdM. Cada un dels tres aspectes s'adreça mitjançant eines diferenciades que s'adaptin a la problemàtica plantejada. L'anàlisi estratègic es basa en entrevistes a usuaris de cadenes de transport per establir els principals requeriments del transportista que es pugui plantejar l'ús d'una AdM. A partir dels requeriments, es defineixen diversos models de cadena de transport, arribant a la conclusió que les cadenes 'push-pull' i 'push against stock' són les candidates que més es beneficiarien d'una AdM, almenys a nivell estratègic. El rol de la terminal s'analitza qualitativament analitzant-ne dos aspectes per separat: d'una banda es crea un model basat en una combinació de valors d'origen estocàstic, determinista i via simulació, per calcular el temps d'operació mínim d'un buc de càrrega rodada a una terminal marítima i la relació que hi ha entre nivell d'ús de la terminal i la seva capacitat. D'altra banda, també s'estableix un marc per quantificar la vulnerabilitat i resiliència de la terminal davant de elements que afectin la seva normal operació i com aquests poden afectar la qualitat percebuda del servei. Finalment, pel que fa als models de negoci pels transportistes, es construeix un model de costos i temps per cada un d'ells, se n'analitza la sensibilitat i el pes de les principals variables que els afecten com a eina per calcular el model de negoci, les característiques de la línia marítima i les tarifes de base a cobrar des de la perspectiva de la naviliera. Per assolir-ho, el model es complementa amb l'adopció d'un model d'elecció modal. Preses conjuntament, es proporciona una metodologia per ajudar a avaluar el potencial de futures AdM o millorar les existents i l'efecte que hi poden tenir les actuals i futures polítiques de transport
Finding the right RoPax vessel size and freight price. A coste and mode choice model
[EN] Motorways of the sea operated as RoPax services are natural competitors with only-road freight haulage transportation. Cost, time and quality perceived are the determinants that make transporters and shippers use one route or another. This research considers the role that shipping companies and their ship deployment and pricing strategy have in the equation, as incentives for modal shift from road to sea. A model of the ships and transporter costs is developed considering different business models for the transporter (accompanied versus unaccompanied cargo) followed with a discrete choice model that, once calibrated, allows to test the influence that variables such as frequency, ship size and commercial speed might play into the competitiveness of a shipping line. As a result, different pricing strategies for the shipping line are developed and the characteristics of the optimal shipping line for each of them are found, to either maximize the profit of the shipping company or the modal shift.DOI: http://dx.doi.org/10.4995/CIT2016.2016.4148http://ocs.editorial.upv.es/index.php/CIT/CIT2016Morales Fusco, P.; Grau Sala, M.; Saurí Marchán, S. (2016). Finding the right RoPax vessel size and freight price. A coste and mode choice model. Editorial Universitat Politècnica de València. 1456-1470. https://doi.org/10.4995/CIT2016.2015.4148OCS1456147
An empirical analysis of the resiliency of Ro/Ro and Ro/Pax terminal operations
Regular maritime lines with roll-on roll-off vessels must offer a reliable service without substantial cost increases in order to be competitive. Port terminals need to be able to respond quickly to any disturbance that might appear and return to a smooth operational state in the minimum amount of time (resilient terminals). In this paper a complete taxonomy of the disturbances affecting the operational processes in a roll-on roll-off terminal is introduced together with a system able to assess the performance of any measure used to mitigate them. The study is based on an overview of the existing literature on the topic, a detailed diagram of the operational processes of the terminal, and an exhaustive set of interviews of the staff involved in the processes occurring in a roll-on roll-off terminal, together with field measurements. The main vulnerabilities are identified and possible corrective and preventive measures are pointed out.Postprint (published version
Inter-terminal transfer between port terminals. A continuous mathematical programming model to optimize scheduling and deployment of transport units
[EN] In most large port cities, the challenge of inter-terminal transfers (ITT) prevails due to the
long distance between multiple terminals. The quantity of containers requiring movement
between terminals as they connect from pre-carrier to on-carrier is increasing with the
formation of the mega-alliances.
The paper proposes a continuous time mathematical programming model to optimize the
deployment and schedule of trucks and barges to minimize the number of operating
transporters, their makespan, costs and the distance travelled by the containers by
choosing the right combination of transporters and container movements while fulfilling
time window restrictions imposed on reception of the containers.
A multi-step routing problem is developed where transporters can travel from one
terminal to another and/or load or unload containers from a specific batch at each step.
The model proves successful in identifying the costless schedule and means of
transportation. And a sensibility analysis over the parameters used is provided.Morales Fusco, P.; Pedrielli, G.; Zhou, C.; Lee, L.; Chew, E. (2016). Inter-terminal transfer between port terminals. A continuous mathematical programming model to optimize scheduling and deployment of transport units. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1471-1481. https://doi.org/10.4995/CIT2016.2015.4149OCS1471148
Assessing customs performance in the Mediterranean ports. KPI selection and Best practices identification as part of the MEDNET project
[EN] The seamless flow of goods, people and investments across the Mediterranean necessitates a well-functioning port and transport system. More efficient port operations enhance seamless logistics and promote safety, efficiency, interoperability and interconnectivity of transport networks in the Mediterranean area.To promote the exchange of knowledge and expertise relevant to port and customs procedures and simplification of clearance for vessels and cargoes in the Mediterranean, the MEDNET project was launched. As part of the project a common evaluation framework for the performance of ports in the form of a set of Key Performance Indicators (KPIs) together with a list of the best practices in terms of operations and customs procedures was developed.In total, 50 ports were analyzed and given a KPI regarding traffic, financial, operational and human resources, sustainability and customs procedures. The values were latter crossed with the current good practices on operation in terms of customs procedures. And a small correlation between KPIs performance and implantation degree of good practices in customs procedures was found. This presentation exposes the methodology to assess the ports’ performance and the best practices identification.Morales Fusco, P.; Saurí Marchán, S.; Lekka, AM.; Karousos, I. (2016). Assessing customs performance in the Mediterranean ports. KPI selection and Best practices identification as part of the MEDNET project. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1482-1500. https://doi.org/10.4995/CIT2016.2015.4221OCS1482150
First-Principles Density Limit Scaling in Tokamaks Based on Edge Turbulent Transport and Implications for ITER
A first-principles scaling law, based on turbulent transport considerations, and a multimachine database of density limit discharges from the ASDEX Upgrade, JET, and TCV tokamaks, show that the increase of the boundary turbulent transport with the plasma collisionality sets the maximum density achievable in tokamaks. This scaling law shows a strong dependence on the heating power, therefore predicting for ITER a significantly larger safety margin than the Greenwald empirical scaling [Greenwald et al., Nucl. Fusion, 28, 2199 (1988)] in case of unintentional high-to-low confinement transition
The role of ETG modes in JET-ILW pedestals with varying levels of power and fuelling
We present the results of GENE gyrokinetic calculations based on a series of JET-ITER-like-wall (ILW) type I ELMy H-mode discharges operating with similar experimental inputs but at different levels of power and gas fuelling. We show that turbulence due to electron-temperature-gradient (ETGs) modes produces a significant amount of heat flux in four JET-ILW discharges, and, when combined with neoclassical simulations, is able to reproduce the experimental heat flux for the two low gas pulses. The simulations plausibly reproduce the high-gas heat fluxes as well, although power balance analysis is complicated by short ELM cycles. By independently varying the normalised temperature gradients (omega(T)(e)) and normalised density gradients (omega(ne )) around their experimental values, we demonstrate that it is the ratio of these two quantities eta(e) = omega(Te)/omega(ne) that determines the location of the peak in the ETG growth rate and heat flux spectra. The heat flux increases rapidly as eta(e) increases above the experimental point, suggesting that ETGs limit the temperature gradient in these pulses. When quantities are normalised using the minor radius, only increases in omega(Te) produce appreciable increases in the ETG growth rates, as well as the largest increases in turbulent heat flux which follow scalings similar to that of critical balance theory. However, when the heat flux is normalised to the electron gyro-Bohm heat flux using the temperature gradient scale length L-Te, it follows a linear trend in correspondence with previous work by different authors
Spectroscopic camera analysis of the roles of molecularly assisted reaction chains during detachment in JET L-mode plasmas
The roles of the molecularly assisted ionization (MAI), recombination (MAR) and dissociation (MAD) reaction chains with respect to the purely atomic ionization and recombination processes were studied experimentally during detachment in low-confinement mode (L-mode) plasmas in JET with the help of experimentally inferred divertor plasma and neutral conditions, extracted previously from filtered camera observations of deuterium Balmer emission, and the reaction coefficients provided by the ADAS, AMJUEL and H2VIBR atomic and molecular databases. The direct contribution of MAI and MAR in the outer divertor particle balance was found to be inferior to the electron-atom ionization (EAI) and electron-ion recombination (EIR). Near the outer strike point, a strong atom source due to the D+2-driven MAD was, however, observed to correlate with the onset of detachment at outer strike point temperatures of Te,osp = 0.9-2.0 eV via increased plasma-neutral interactions before the increasing dominance of EIR at Te,osp < 0.9 eV, followed by increasing degree of detachment. The analysis was supported by predictions from EDGE2D-EIRENE simulations which were in qualitative agreement with the experimental observations
Shattered pellet injection experiments at JET in support of the ITER disruption mitigation system design
A series of experiments have been executed at JET to assess the efficacy of the newly installed shattered pellet injection (SPI) system in mitigating the effects of disruptions. Issues, important for the ITER disruption mitigation system, such as thermal load mitigation, avoidance of runaway electron (RE) formation, radiation asymmetries during thermal quench mitigation, electromagnetic load control and RE energy dissipation have been addressed over a large parameter range. The efficiency of the mitigation has been examined for the various SPI injection strategies. The paper summarises the results from these JET SPI experiments and discusses their implications for the ITER disruption mitigation scheme
New H-mode regimes with small ELMs and high thermal confinement in the Joint European Torus
New H-mode regimes with high confinement, low core impurity accumulation, and small edge-localized mode perturbations have been obtained in magnetically confined plasmas at the Joint European Torus tokamak. Such regimes are achieved by means of optimized particle fueling conditions at high input power, current, and magnetic field, which lead to a self-organized state with a strong increase in rotation and ion temperature and a decrease in the edge density. An interplay between core and edge plasma regions leads to reduced turbulence levels and outward impurity convection. These results pave the way to an attractive alternative to the standard plasmas considered for fusion energy generation in a tokamak with a metallic wall environment such as the ones expected in ITER.& nbsp;Published under an exclusive license by AIP Publishing
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