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As rail networks face increasing pressure to improve punctuality and capacity under mixed-traffic conditions, digital support tools such as Connected Driver Advisory Systems (C-DAS) are increasingly deployed. Yet, empirical evidence of their operational effects in daily practice remains limited. This paper presents a data-driven two-level approach based on macroscopic and microscopic event graph representations, constructed from the same underlying corridor and observed train movements, to evaluate the performance of C-DAS. It fuses timetable event records, track section occupation and release data, and C-DAS usage logs to enable comparison between trains operated with and without C-DAS at timetable point and block section levels. Derived from the event graphs, differences in timetable deviation, running time deviation, and the occurrence of unplanned yellow signal aspects are assessed using non-parametric statistical tests. The approach is demonstrated through its application to RouteLint, a C-DAS deployed for freight operations in the Netherlands, using one year of data from a mixed-traffic mainline corridor comprising 23,573 freight train runs. The results show modest but consistent differences in operational performance between trains operated with and without RouteLint. Statistically significant differences in timetable deviation are identified at multiple key locations, with RouteLint-equipped trains showing approximately 30–70 s lower deviations at major stations and junctions. At the microscopic level, running time deviations exhibit substantial local variability, while lower deviations are observed on selected block sections for RouteLint-equipped trains. In addition, RouteLint-equipped trains show approximately 6% lower overall odds that an observed yellow signal aspect is unplanned, while the association varies across operating contexts.
Zeolite 4A was selected because of its strong affinity for water at low partial pressures. Water adsorption equilibrium was represented using a Dual-Site Langmuir 2 model, while mass transfer was described using the Linear Driving Force model. A non-isothermal packed-bed model was developed for a hydrogen feed containing 872 ppmv water at 25 bar, 298.15 K, and a flow rate of 0.0223 kmol s−1. Several PSA configurations were tested, including conventional pressure regeneration, vacuum regeneration, and temperature-assisted vacuum regeneration. Conventional regeneration at 1 bar produced only limited reduction in solid water loading, while deep-vacuum simulations showed numerical convergence problems during multi-cycle operation. Therefore, the detailed cyclic and economic assessment was continued using TSA.
For the TSA process, the simulated breakthrough time was approximately 19 250 s, and an adsorption time of 14 000 s was selected to provide a safety margin before water breakthrough. Regeneration w
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Zeolite 4A was selected because of its strong affinity for water at low partial pressures. Water adsorption equilibrium was represented using a Dual-Site Langmuir 2 model, while mass transfer was described using the Linear Driving Force model. A non-isothermal packed-bed model was developed for a hydrogen feed containing 872 ppmv water at 25 bar, 298.15 K, and a flow rate of 0.0223 kmol s−1. Several PSA configurations were tested, including conventional pressure regeneration, vacuum regeneration, and temperature-assisted vacuum regeneration. Conventional regeneration at 1 bar produced only limited reduction in solid water loading, while deep-vacuum simulations showed numerical convergence problems during multi-cycle operation. Therefore, the detailed cyclic and economic assessment was continued using TSA.
For the TSA process, the simulated breakthrough time was approximately 19 250 s, and an adsorption time of 14 000 s was selected to provide a safety margin before water breakthrough. Regeneration w
The Spherical Approximation in MOND
Quantifying Geometric Biases in the Radial Acceleration Relation
The Radial Acceleration Relation (RAR) is one of the most striking empirical regularities in galactic dynamics: the observed centripetal acceleration in galaxies correlates tightly with the acceleration predicted from the baryonic mass distribution alone. Modified Newtonian Dynamics (MOND) naturally explains this relation, while the standard dark matter paradigm requires fine-tuning. However, nearly all observational tests of the RAR adopt a simplifying approximation: the baryonic acceleration at radius r is computed as g_bar = GM(<r)/r², as if the galaxy’s mass distribution were spherically symmetric. Real disk galaxies are highly flattened, and the validity of this approximation has never been directly quantified for the Radial Acceleration Relation.
This thesis addresses two questions: (1) How accurate is the spherical approximation for computing baryonic accelerations in disk galaxies? (2) Does its use bias previous tests of the MOND RAR? Using a numerical AQUAL solver applied to realistic three-dimensional stellar density reconstructions from Spitzer 3.6 μm imaging, we compare the spherical approximation to the true disk gravity for three galaxies spanning a range of morphologies: NGC 2841 (bulge-dominated), NGC 3198 (moderate bulge), and NGC 2976 (bulgeless).
We find that the accuracy of the spherical approximation for computing baryonic acceleration
Modelling Ground Vibrations Induced by Pile Removal
From Free-Field Propagation to Simplified Soil-Structure Interaction
Measured vibration data showed a non-stationary response, with the dominant frequency during pile removal developing from approximately 6-7~Hz towards a sustained component around 14~Hz. Because the mechanical source force was unknown, model-dependent equivalent vertical and radial forces were identified from near-source measurements and used as input to a two-dimensional axisymmetric free-field model. The soil profile was derived from 24 CPT soundings, with dynamic properties estimated using empirical correlations. Comparison with far-field measurements showed that the calibrated model reproduced the dominant frequencies more consistently than the absolute vibration amplitudes.
The calibrated free-field model was subsequently extended towards SSI using two fictive embedded receivers with different embedment depths. Fully coupled FE models were used as numerical references and compared with engineering spring-dashpot, uncoupled numerical impedance and coupled numerical impedance formulations. The main differences between the SSI approaches occurred in response amplitude rather than dominant frequency. Within the investigated interface discretisations, the engineering and uncoupled formulations showed the most consistent agreement with the fully coupled references. The uncoupled formulation showed little sensitivity to interface refinement, whereas the coupled formulation was more sensitive to segment size. Refinement improved several coupled response components, although formal convergence was not established.
The results demonstrate a structured approach for predicting the transmission of construction-induced vibrations through the source-soil-receiver chain when source and dynamic soil information are limited. The SSI comparison is methodological rather than building-specific, as the fictive axisymmetric receivers do not represent the actual TNW structure. Further measurements, improved dynamic soil characterisation and building-specific three-dimensional modelling are required for quantitative predictions of vibration levels inside TNW.
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Measured vibration data showed a non-stationary response, with the dominant frequency during pile removal developing from approximately 6-7~Hz towards a sustained component around 14~Hz. Because the mechanical source force was unknown, model-dependent equivalent vertical and radial forces were identified from near-source measurements and used as input to a two-dimensional axisymmetric free-field model. The soil profile was derived from 24 CPT soundings, with dynamic properties estimated using empirical correlations. Comparison with far-field measurements showed that the calibrated model reproduced the dominant frequencies more consistently than the absolute vibration amplitudes.
The calibrated free-field model was subsequently extended towards SSI using two fictive embedded receivers with different embedment depths. Fully coupled FE models were used as numerical references and compared with engineering spring-dashpot, uncoupled numerical impedance and coupled numerical impedance formulations. The main differences between the SSI approaches occurred in response amplitude rather than dominant frequency. Within the investigated interface discretisations, the engineering and uncoupled formulations showed the most consistent agreement with the fully coupled references. The uncoupled formulation showed little sensitivity to interface refinement, whereas the coupled formulation was more sensitive to segment size. Refinement improved several coupled response components, although formal convergence was not established.
The results demonstrate a structured approach for predicting the transmission of construction-induced vibrations through the source-soil-receiver chain when source and dynamic soil information are limited. The SSI comparison is methodological rather than building-specific, as the fictive axisymmetric receivers do not represent the actual TNW structure. Further measurements, improved dynamic soil characterisation and building-specific three-dimensional modelling are required for quantitative predictions of vibration levels inside TNW.