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See detailDynamic Modeling and control of a pilot CO2 postcombustion capture plant
Léonard, Grégoire ULg; Cabeza Mogador, Bruno; Belletante, Ségolène et al

Poster (2013, June)

A dynamic model of a post-combustion capture pilot plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A ... [more ▼]

A dynamic model of a post-combustion capture pilot plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A washing section where the flue gas from the absorber is washed with cold water is included to the process in order to reduce the emissions of amine to the air. Control of the water balance in the solvent loop is successfully achieved by changing the washing water temperature. In previous publications regarding CO2 capture pilot plants, the regulation of the water balance always required a water make-up flow which appears here as unnecessary. Rejection of disturbances and different load reduction scenarios are tested to confirm the efficiency of this strategy. Potential operational problems of this control strategy are identified and solved. [less ▲]

Detailed reference viewed: 24 (3 ULg)
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See detailDynamic modeling and control strategies for Organic Rankine Cycle systems
Quoilin, Sylvain ULg; Lemort, Vincent ULg

Conference (2012, September 13)

Control and optimization are major issues in ORC systems applied to waste heat sources. This talk provides an overview of the current state of the art and of the main areas of R&D in that topic, including ... [more ▼]

Control and optimization are major issues in ORC systems applied to waste heat sources. This talk provides an overview of the current state of the art and of the main areas of R&D in that topic, including: - Steady-state and dynamic modeling of ORC cycles (simulation platforms, modeling paradigms, numerical issues) - Optimization of the working conditions for a given heat source and heat sink, and in particular of the evaporating temperature - Optimal start-up and shut-down strategies (grid synchronization, pressure overshoot, ...) - Control of the cycle under transient heat source conditions - Traditional and advanced controllers (PID, Model predictive control) The different adjustable working conditions (condensing/evaporating temperature, superheating, subcooling, working fluid flow rate) are listed with regard to the available degrees of freedom (pump/expander speed, secondary fluid flow rates and temperatures) and their optimal values are derived, depending on the target application. [less ▲]

Detailed reference viewed: 322 (9 ULg)
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See detailDynamic modeling and optimal control strategy of waste heat recovery Organic Rankine Cycles
Quoilin, Sylvain ULg; Aumann, Richard; Grill, Andreas et al

in Applied Energy (2011)

Organic Rankine Cycles (ORCs) are particularly suitable for recovering energy from low-grade heat sources. This paper describes the behavior of a small scale ORC used to recover energy from a variable ... [more ▼]

Organic Rankine Cycles (ORCs) are particularly suitable for recovering energy from low-grade heat sources. This paper describes the behavior of a small scale ORC used to recover energy from a variable flow rate and temperature waste heat source. A traditional static model is unable to predict transient behavior in a cycle with a varying thermal source, whereas this capability is essential for simulating an appropriate cycle control strategy during part-load operation and start and stop procedures. A dynamic model of the ORC is therefore proposed focusing specifically on the time-varying performance of the heat exchangers, the dynamics of the other components being of minor importance. Three different control strategies are proposed and compared. The simulation results show that a model predictive control strategy based on the steady-state optimization of the cycle under various conditions is the one showing the best results. [less ▲]

Detailed reference viewed: 338 (29 ULg)
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See detailDynamic Modeling and Validation of Radiant Ceiling Systems Coupled to its Environment
Fonseca, Néstor; Cuevas, Cristian; Lemort, Vincent ULg

(2010, July)

This paper presents the results of a study performed in order to develop a dynamic model of radiant ceiling panels in heating or cooling modes coupled to its environment (fenestration, walls, internal ... [more ▼]

This paper presents the results of a study performed in order to develop a dynamic model of radiant ceiling panels in heating or cooling modes coupled to its environment (fenestration, walls, internal loads and ventilation system). The model considers the radiant panels as a dynamic-state finned heat exchanger connected to a detailed lumped dynamic model of the building (R-C network). The behavior of the radiant ceiling system and the interactions with its environment has been experimentally and numerically evaluated. Using as inputs the radiant ceiling and room dimensions, material properties and the transient measurements of air temperature at the adjacent zones, supply air and water temperatures and mass flow rates, the model allows for the estimation of the water exhaust temperature, radiant ceiling average surface temperature, resultant and dry air room temperatures, radiant ceiling power and internal surface temperatures of the room in order to compare with measurements taken during the commissioning process. Two dynamic tests in heating and cooling modes are used to validate the model. [less ▲]

Detailed reference viewed: 43 (6 ULg)
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See detailDynamic Modeling andControl System Definition for a Micro-CSP Plant Coupled with Thermal Storage Unit
Ireland, Melissa; Orosz, Matthew; Brisson, John et al

in Proceedings of TurboExpo 2014 (2014)

Organic Rankine cycle (ORC) systems are gaining ground as a means of effectively providing sustainable energy. Coupling small-scale ORCs powered by scroll expander-generators with solar thermal collectors ... [more ▼]

Organic Rankine cycle (ORC) systems are gaining ground as a means of effectively providing sustainable energy. Coupling small-scale ORCs powered by scroll expander-generators with solar thermal collectors and storage can provide combined heat and power to underserved rural communities. Simulation of such systems is instrumental in optimizing their control strategy. However, most models developed so far operate at steady-state or focus either on ORC or on storage dynamics. In this work, a model for the dynamics of the solar ORC system is developed to evaluate the impact of variable heat sources and sinks, thermal storage, and the variable loads associated with distributed generation. This model is then used to assess control schemes that adjust operating conditions for daily environmental variation. [less ▲]

Detailed reference viewed: 32 (1 ULg)
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See detailDynamic modelling and control of a pilot plant for post-combustion CO2 capture
Léonard, Grégoire ULg; Cabeza Mogador, Bruno; Belletante, Ségolène et al

in Computer Aided Chemical Engineering (2013), 31

A dynamic model of a post-combustion pilot capture plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A ... [more ▼]

A dynamic model of a post-combustion pilot capture plant is developed using Aspen Plus Dynamics. An innovative process control strategy is studied for regulating the water balance of the process. A washing section where the flue gas from the absorber is washed with cold water is included to the process in order to reduce the emissions of amine to the air. Control of the water balance in the solvent loop is successfully achieved by changing the washing water temperature. In previous publications regarding CO2 capture pilot plants, the regulation of the water balance always required a water make-up flow which appears here as unnecessary. Rejection of disturbances and different load reduction scenarios are tested to confirm the efficiency of this strategy. Potential operational problems of this control strategy are identified and solved. [less ▲]

Detailed reference viewed: 107 (17 ULg)
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See detailDynamic modelling of reservoir sedimentation in a semi-arid watershed
Adam, Nicolas; Erpicum, Sébastien ULg; Chenaoui, Bakhta et al

E-print/Working paper (2014)

Sedimentation in large reservoirs is a major issue in semi-arid regions characterized by severe seasonal water scarcity. As a contribution to improved sediment management, this study analyses the real ... [more ▼]

Sedimentation in large reservoirs is a major issue in semi-arid regions characterized by severe seasonal water scarcity. As a contribution to improved sediment management, this study analyses the real case of the reservoir of Sidi Yacoub in the north of Algeria. First, a dynamic model of the reservoir was set up and used to estimate hydraulic and sediment inflows, during the period 1990-2010, based on data recorded by the dam operator and measurements at a gauging station located downstream of the reservoir. Second, based on a statistical characterization of inflow and outflow discharges, a projection of future sedimentation was performed until 2030, using the assumption of stationarity of the statistical distributions. Third, the model was used to investigate the influence of possible climate change and to quantify the positive effects of measures to control erosion in the watershed. [less ▲]

Detailed reference viewed: 7 (3 ULg)
See detailDynamic Modelling, Simulation Analysis---Useful for Understanding Biology?
Bullinger, Eric ULg

Scientific conference (2005, November 11)

Detailed reference viewed: 4 (0 ULg)
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See detailDynamic MR Based Analysis of Tumor Movement in Upper and Mid Lobe Localized Lung Cancer
Kovacs; Hadjiev; LAKOSI, Ferenc ULg et al

in Pathology Oncology Research (2008)

Detailed reference viewed: 4 (0 ULg)
See detailDynamic multilevel filtering for real-time estimation of electric power systems
Mallieu, Didier; Van Cutsem, Thierry ULg; Rousseaux, Patricia ULg et al

in Control, Theory and Advanced Technology (1986), 2(2), 255-272

Detailed reference viewed: 16 (1 ULg)
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See detailA dynamic neighbourhood discovery protocol for active overlay networks
Martin, Sylvain ULg; Leduc, Guy ULg

in Lecture Notes in Computer Science (2004), 2982

d-RADAR(1) is a neighbourhood discovery protocol for overlay network environments designed for (but not limited to) active network overlays. The core of the algorithm is an expanding ring-search based on ... [more ▼]

d-RADAR(1) is a neighbourhood discovery protocol for overlay network environments designed for (but not limited to) active network overlays. The core of the algorithm is an expanding ring-search based on the IP routing table content augmented with traffic-based and dynamic refreshing techniques that allows it to react to virtual topology changes (nodes joining/leaving the overlay) as well as IP topology changes (broken and repaired link, route changes and moving nodes). This paper presents how the protocol detects overlay candidate nodes using probing capsules and the algorithms needed to select neighbours among the candidates. We also show how d-RADAR keeps the neighbouring table up to date and learns topology changes while keeping a low discovery and refresh overhead. A short summary of simulations carried out with our active network simulator illustrates how these algorithms actually behave. [less ▲]

Detailed reference viewed: 45 (17 ULg)
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See detailDynamic Nucleocytoplasmic Shuttling of an Arabidopsis SR Splicing Factor: Role of the RNA-Binding Domains
Rausin, Glwadys ULg; Tillemans, Vinciane ULg; Stankovic, Nancy ULg et al

in Plant Physiology (2010), 153

Serine/arginine-rich (SR) proteins are essential nuclear-localized splicing factors. We have investigated the dynamic subcellular distribution of the Arabidopsis (Arabidopsis thaliana) RSZp22 protein, a ... [more ▼]

Serine/arginine-rich (SR) proteins are essential nuclear-localized splicing factors. We have investigated the dynamic subcellular distribution of the Arabidopsis (Arabidopsis thaliana) RSZp22 protein, a homolog of the human 9G8 SR factor. Little is known about the determinants underlying the control of plant SR protein dynamics, and so far most studies relied on ectopic transient overexpression. Here, we provide a detailed analysis of the RSZp22 expression profile and describe its nucleocytoplasmic shuttling properties in specific cell types. Comparison of transient ectopic- and stable tissue-specific expression highlights the advantages of both approaches for nuclear protein dynamic studies. By site-directed mutagenesis of RSZp22 RNA-binding sequences, we show that functional RNA recognition motif RNP1 and zinc-knuckle are dispensable for the exclusive protein nuclear localization and speckle-like distribution. Fluorescence resonance energy transfer imaging also revealed that these motifs are implicated in RSZp22 molecular interactions. Furthermore, the RNA-binding motif mutants are defective for their export through the CRM1/XPO1/Exportin-1 receptor pathway but retain nucleocytoplasmic mobility. Moreover, our data suggest that CRM1 is a putative export receptor for mRNPs in plants. [less ▲]

Detailed reference viewed: 61 (31 ULg)
Peer Reviewed
See detailDynamic of seed dispersal by large frugivores in a forest-savanna mosaic subject to anthropic pressure in Western D.R. Congo
Trolliet, Franck ULg; Serckx, Adeline; Huynen, Marie-Claude ULg et al

Poster (2013, April 05)

The Western Congolian forest-savanna mosaic is an ecotone subject to anthropogenic as well as natural fragmentation. Its forests have thus a considerable proportion of edges. This vegetation structure is ... [more ▼]

The Western Congolian forest-savanna mosaic is an ecotone subject to anthropogenic as well as natural fragmentation. Its forests have thus a considerable proportion of edges. This vegetation structure is likely to impact animal and plant communities and its dynamics such as animal mediated seed dispersal. Synergetically, activities such as bush meat hunting deplete large frugivores populations and thus decrease recruitment potential of the plants they disperse. Indeed, zoochory is known to be of great importance for tropical forests and a number of studies proved that large-seeded tree species closely depend on large frugivores for their regeneration. In such a context, we aim to understand how forest edges affect the dynamics of seed dispersal. More precisely, we wonder if the interactions between large seeds and their dispersers and predators are affected when closer to edges and how this can impact plant regeneration capacity. Also, we wonder if the dispersal and regeneration of large-seeded tree species depend on a few disproportionally important frugivores species. Bonobos, Pan paniscus, are among the largest frugivores left in the area and thus likely to be disproportionally important seed dispersers, though, their role as seed dispersers has yet been little investigated. We thus focus on the qualitative role for seed dispersal of the potentially keystone and umbrella ape species, the bonobo. To answer those questions, we study the main steps characteristics of large-seeded tree species regeneration process; namely quantitative seed dispersal, seed deposition pattern, germination capacity after transit in frugivore’s gut and, seed and seedling fate. By studying five different tree species at varying distances from forest edge, we aim to drive an inter-species comparison and to highlight the effect of forest edge on the regeneration process. We first quantify the seed production for each tree species and then evaluate the quantitative capacity of seed dispersal. By combining direct focal observations and camera trapping, we are able to highlight variations in composition of dispersers community and their respective contribution to seed dispersal. A literature review on each disperser species’ seed retention time and habitat use will allow the computation of the seed dispersal kernels. We will also evaluate the effect of seed ingestion by the bonobo on its germination capacity: seeds will be collected from dung to evaluate the effect of seed ingestion on the rate and velocity of germination. Finally, we will study the predation pressure exerted on dispersed and non-dispersed seeds and seedlings by setting up two sets of seeds below the canopy of parent trees and away from any conspecific trees. One set will be dispersed unprotected to seed predators; another one will be enclosed in a cage and permit seeds to germinate, allowing us to evaluate the herbivores pressure on seedlings. [less ▲]

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See detailDynamic peer-to-peer competition
Caram, L. F.; Caiafa, C. F.; Proto, A. N. et al

in Physica A: Statistical Mechanics and its Applications (2010), 389(13), 2628-2636

The dynamic behavior of a multiagent system in which the agent size si is variable it is studied along a Lotka-Volterra approach. The agent size has hereby the meaning of the fraction of a given market ... [more ▼]

The dynamic behavior of a multiagent system in which the agent size si is variable it is studied along a Lotka-Volterra approach. The agent size has hereby the meaning of the fraction of a given market that an agent is able to capture (market share). A Lotka-Volterra system of equations for prey-predator problems is considered, the competition factor being related to the difference in size between the agents in a one-on-one competition. This mechanism introduces a natural self-organized dynamic competition among agents. In the competition factor, a parameter sigma is introduced for scaling the intensity of agent size similarity, which varies in each iteration cycle. The fixed points of this system are analytically found and their stability analyzed for small systems (with n = 5 agents). We have found that different scenarios are possible, from chaotic to non-chaotic motion with cluster formation as function of the a parameter and depending on the initial conditions imposed to the system. The present contribution aim is to show how a realistic though minimalist nonlinear dynamics model can be used to describe the market competition (companies, brokers, decision makers) among other opinion maker communities. (C) 2010 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 14 (1 ULg)
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See detailDynamic Prediction of Energy Delivery Capacity of Power Networks : Unlocking the Value of Real-Time Measurements.
Schell, Peter; Jones, Lauren; Mack, Philippe et al

in Proceedings of the third IEEE PES Conference on Innovative Smart Grid Technologies (2012, January)

This paper describes recent advances in prediction software using advanced data-mining tools, and shows how this can significantly increase the operational value of the data gathered. These new tools ... [more ▼]

This paper describes recent advances in prediction software using advanced data-mining tools, and shows how this can significantly increase the operational value of the data gathered. These new tools allow for new operational procedures to be defined that increase the usages of the network without decreasing security of supply. We will use the example of dynamic line rating, i.e. determining the thermal rating of an overhead line based on real-time environmental parameters (temperature, wind speed & direction and solar radiation) to highlight how the use of numerical data-mining tools can help us reliably predict future behavior of power networks. [less ▲]

Detailed reference viewed: 56 (10 ULg)
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See detailDynamic processes in sea ice captured by the temporal evolution of its biogeochemical
Zhou, Jiayun; Tison, Jean-Louis; Eicken, Hajo et al

in VLIZ Special Publication (2011), 48

Detailed reference viewed: 16 (4 ULg)