| 1. |
- Das, Prabir Kumar, et al.
(author)
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Micromechanical investigation ofphase separation in bitumen bycombining atomic force microscopywith differential scanning calorimetryresults
- 2013
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In: International Journal on Road Materials and Pavement Design. - : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 14:S1, s. 25-37
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Journal article (peer-reviewed)abstract
- The thermo-rheological behaviour of bitumen depends largely on its chemical structure and intermolecular microstructures. Bitumen is a complex mixture of organic molecules of different sizes and polarities for which the micro-structural knowledge is still rather incomplete. Knowledge at that level can have great implications for behaviour at a larger scale and will help to optimise the bitumen in its production stage. The present study is focused on understanding the fundamental mechanisms behind the micro-structural phase appearance and the speed or mobility at which they change. To do so, atomic force microscopy was utilised at different temperatures to investigate the phase separation behaviour for four different types of bitumen and co-relate it with the differential scanning calorimetry measurements. Based on the experimental evidences, it was found that the observed phase separation is mainly due to the wax/paraffin fraction presence in bitumen and that the investigated bitumen behaves quite differently. Recommendations are made to continue this research into qualitative information to be used on the asphalt mix design level.
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| 2. |
- Zhu, Jiqing, et al.
(author)
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Microstructure evaluation of polymer-modified bitumen by image analysis using two-dimensional fast Fourier transform
- 2018
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In: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 137, s. 164-175
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Journal article (peer-reviewed)abstract
- Aiming to quantitatively evaluate the microstructure of polymer-modified bitumen (PMB) for roads, this paper employs the two-dimensional fast Fourier transform (2D-FFT) to process the microscopic and numerical images of four PMBs. The related derivative parameters, including the characteristic frequency and wavelength, are computed from the 2D-FFT power spectrum. The results show that the absence/presence of a characteristic frequency (range) on the power spectrum can indicate the lack/existence of the corresponding periodical structural pattern(s) in the original PMB image. A lower characteristic frequency usually represents a coarser PMB microstructure while a higher one implies a finer PMB microstructure. The 2D-FFT method is thus valid for differentiating various PMB microstructures. The proposed method is also capable of quantitatively evaluating the effects of temperature and the temporal evolution of PMB microstructure during phase separation. As the separation continues, the decrease of characteristic frequency indicates the coarsening process of a PMB microstructure. Additionally, the numerical reproduction of the observed phase separation is evaluated with the same method. The quantitative comparison with the experimental results reveals that the simulations fairly reproduced the microscopy observation results despite some deviation. The proposed method provides a foundation for the microstructure-based modelling of PMB performance in the future.
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| 3. |
- Abourraja, Mohamed Nezar, et al.
(author)
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A simulation-based decision support framework devoted to Ro-Ro terminals : Design, implementation and evaluation
- 2023
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In: Computers & industrial engineering. - : Elsevier BV. - 0360-8352 .- 1879-0550. ; 180, s. 109248-
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Journal article (peer-reviewed)abstract
- As a type of intermodal terminal, pure Ro-Ro terminals are one of the most important logistic hubs in the supply chain for rolling freight stored in containerized and wheeled steel boxes. These large-scale systems are highly complex, with nonlinear and hard-to-predict behavior evolving in a stochastic environment. Consequently, making decisions about any problem thereof is no mean feat, particularly for terminal planners. To assist them in decision-making, a pool of relevant models and tools have been developed over the years in the literature. Nevertheless, models that are oriented toward specific objectives dominate, and generic ones are rare. This paper tries to fill this gap and proposes a generic framework to be used as a factory to create specific decision support models based on simulation for pure Ro-Ro terminals. This framework is formulated following two artifacts: (1) the known classification of key performance indicators combined with the typical functional and physical organization of pure Ro-Ro terminals; (2) the three main arteries of harbor systems, namely flows, decisions and operations. Then a scalable way of making decisions based on a flexible form of the cost function weighted according to a set of coefficients is integrated. These designed coefficients allow decision-makers a wide flexibly in choosing how the best solutions are determined. An application of this framework is illustrated through a real case study, where the weights are estimated using an expert-profiling based approach then pushed into the OptQuest optimizer to be calibrated before analyzing the results. These results are aggregated, then expressed as scores on a scale of 0 to 1. This is to help terminal planners to easily identify the worst and best planning scenarios as well as the relationships and compatibilities between the involved handling rules to suggest different alternatives for managing operations.
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| 4. |
- Abourraja, Mohamed Nezar, et al.
(author)
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Exploiting simulation model potential in investigating handling capacity of Ro-Ro terminals: The case study of Norvik seaport
- 2022
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In: Simulation Modelling Practice and Theory. - : Elsevier BV. - 1569-190X. ; 117, s. 102513-102513
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Journal article (peer-reviewed)abstract
- In this paper, the spotlight is directed towards studying the handling capacity of pure Ro-Ro terminals, especially the new terminal of Norvik port. To this end, a simulation model based on a distributed architecture is built to assess the handling capacity under different flow scenarios with a particular focus on the trailer flow and export-lorry flow the terminal can handle in terms of resource availability, trailer-dwell times and management rules. This helped to determine the number of resources required to evacuate smoothly the incoming flows and to identify where potential bottlenecks happen the most inside the terminal. The established model is verified then validated by experts to conduct properly the experiment study where the model is fed with empirical data provided by terminal authorities. This experiment showed that the terminal can handle flows of which trailers do not exceed 17% and the export fraction of lorries is at most 42%.
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| 5. |
- Abourraja, Mohamed Nezar, et al.
(author)
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Proposal of a module-driven architecture for building simulation models devoted to container terminals : dilemmas in applying generic, flexible, and modular principles
- 2023
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In: Simulation (San Diego, Calif.). - : SAGE Publications. - 0037-5497 .- 1741-3133. ; 99:7, s. 703-727
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Journal article (peer-reviewed)abstract
- Container terminals are complex systems where containerized cargo undergoes a set of processing and handling operations to be delivered to their outgoing modes. A pool of decision support methods and simulation models has been developed to assist planners and managers in making decisions about daily operations. Nevertheless, most are designed for a particular terminal and not generic types. Indeed, a generic model serves as a conceptual factory to create specific models which greatly reduces the time and efforts of development; however, building such a model is no mean feat. To this aim, the paper on hand discusses the complexity of applying genericity, flexibility, and modularity in system modeling and proposes a generic architecture to build modular and flexible simulation models for container terminals. This architecture is split into a set of smaller, manageable, well-connected, and generic modules that facilitate the creation of highly parametrized specific models. An illustrative example of the architecture usage is presented in a case study, the new container terminal of Stockholm, and the resulting models were validated by subject matter experts. Finally, to prove its efficiency, a numerical study fed with real data is conducted to investigate the handling capacity of the studied system under different handling and flow scenarios. The obtained results show that the terminal handling capacity can be increased by around 50% if three to four more straddle carriers are added to the existing fleet.
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| 6. |
- Baldo, N, et al.
(author)
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Calibration and Validation of a Visco-Elasto-Plastic Constitutive Model for Bituminous Conglomerates
- 2009
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In: ADVANCED TESTING AND CHARACTERISATION OF BITUMINOUS MATERIALS. - Rhodes, Greece : CRC Press. - 9780415558549 ; , s. 879-888
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Conference paper (peer-reviewed)abstract
- The paper presents and discusses the calibration and validation of a three-dimensional constitutive visco-elasto-plastic model developed for the analysis of the mechanical behaviour of bituminous mixes. The methodology, an inverse problem technique, uses a one-dimensional analytic formulation of the constitutive model and four different algorithms of non-linear constrained optimisation: the Conjugate Gradient, Montecarlo, Davidon-Fletcher-Powell and Simplex. On the basis of the creep recovery data obtained from an experiment in support of the model calibration, it was verified that the values of the constitutive parameters can be reliably identified, even starting from different initial guesses. A subsequent comparison between the experimental creep curves and numerical ones of the 3-D model demonstrated minimal shifts, confirming the robustness of the identification procedure for the parameters.
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| 7. |
- Balieu, Romain, et al.
(author)
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Life Cycle Sustainability Assessment of Electrified Road Systems
- 2019
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In: ROAD MATERIALS AND PAVEMENT DESIGN. - Abingdon, UK : Taylor & Francis. - 1468-0629 .- 2164-7402. ; 20:sup1, s. S19-S33
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Journal article (peer-reviewed)abstract
- The widespread use of Electric Vehicles (EVs) has been one of the main directionsfor pursuing a sustainable future of road transport in which, the deployment ofthe associated charging infrastructures, static or dynamic, has been included as oneof the main cornerstones for its success. Different electrified road (eRoad) systemswhich allow for dynamic charging of EVs by transferring electrical power from theroad to the vehicle in-motion, either in a conductive or contactless way, are underactive investigation. One of the important tasks in feasibility analysis of suchinfrastructure is to quantitatively assess its environmental performance and, thus,the consequential influences to the sustainability of road electrification as a whole.Having this concern in mind, in this study, a systematic LCA study is carried out in which the environmental impacts from the different life cycle stages have beencalculated and compared among several promising eRoad systems. In a next step,suitable strategies can be accordingly made to minimize these impacts in a most effectiveway; and more importantly, the LCA results of this study can serve as one ofthe important bases for conducting a more comprehensive and objective evaluationof the potential environmental benefits EVs could bring.
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| 8. |
- Balieu, Romain, et al.
(author)
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Multiplicative viscoelastic-viscoplastic damage-healing model for asphalt-concrete materials
- 2016
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In: RILEM Bookseries. - Dordrecht : Springer Netherlands. ; , s. 235-240
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Conference paper (peer-reviewed)abstract
- A viscoelastic-viscoplastic model based on a thermodynamic approach is developed under finite strain in this paper. By introducing a damage evolution, the proposed model is able to reproduce the behavior of Asphalt-Concrete materials until the complete fracture. Moreover, a recoverable part of the degradation is introduced to reproduce the self-healing observed under a sufficiently long rest period. The proposed model is implemented into a Finite Element code and good correlations between the numerical responses and the experiments have been observed.
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| 9. |
- Belitz-Hellwich, Wiebke
(author)
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An Ontology-Based Platform for Information Integration : Supporting Sustainable Smart Transportation Infrastructure
- 2023
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Licentiate thesis (other academic/artistic)abstract
- Transportation and transportation infrastructure are major contributors to global emissions. Even though most of these emissions can be attributed to fuel consumption of vehicles, some of it is due to pavement construction and maintenance. Improving the condition and extending the life span of transportation infrastructure is an integral part to helping reduce infrastructure related emissions. A better understanding of mutual effect of traffic and infrastructure condition is needed to reach this goal. In this thesis the aim is to synchronize logistics operations and pavement condition in a port environment. For this purpose, a logistics simulation model and a Finite Element (FE) model are connected through a system of ontologies, that facilitate information exchange between the models. The suggested approach consists of two connected ontologies (one for logistics operations and one for pavements), interfaces between the models and the ontologies, as well as an application that runs the exchange. Additionally, performance tests have been carried out to judge the impact of the integration on run time of the individual applications.
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| 10. |
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