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Solid State Structure and Lyotropic Mesomorphism of Rare-Earth Trisdode cylsulphates in the Water-Ethylene Glycol System

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Journal of Rare Earths 2003年第2期21卷 101-104页

作者： Liesbet Jongen koen Binnemans KatholiekeUniversiteitLeuven KatholiekeUniversiteitLeuven DepartmentofChemistryCelestijnenlaan200FB3001LeuvenBelgiumDepartmentofChemistryCelestijnenlaan200FB3001LeuvenBelgium

The phase behaviour of lanthanide(Ⅲ) dodecylsulphates, Ln(C 12 H 25 SO 4) 3, by thermo optical microscopy using Lawrence penetration technique was investigated. The lyotropic phase behaviour of lanthanide(Ⅲ) dodecylsulphates in ethylene glycol water in mixtures hereof, depends on the composition of the solvent. For pure ethylene glycol and mixtures of ethylene glycol and water three different mesophases are formed, i.e. a lamellar, a cubic and a hexagonal phase, whereas when water is used as solvent no cubic phase is formed. The size of the lanthanide ion has no influence on the mesomorphism of these metallomesogens, although the smaller the lanthanide ion the lower the solubility.

关键词： inorgamic chemistry lanthanides liquid crystals lyotropic mesophases metallomesogens surfactants rare earths

Transition Modelling with the k-Ω Turbulence Model and an Intermittency Transport Equation

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Journal of Thermal Science 2004年第3期13卷 220-225页

作者： koen LODEFIER Bart MERCI Chris De LANGHE Erik DICK Ghent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent Belgium

In gas turbine engines, laminar-turbulent transition occurs. However, generally, the turbulence models to describe such transition results in too early and too short transition. Combining a turbulence model with a description of intermittency, i.e. the fraction of time the flow is turbulent during the transition phase, can improve it. By letting grow the intermittency from zero to unity, start and evolution of transition can be imposed. In this paper, a method where a dynamic equation of intermittency combining with a two-equation k-ωturbulence model is described. This intermittency factor is a premultiplicator of the turbulent viscosity computed by the turbulence model. Following a suggestion by Menter et al.[1], the start of transition is computed based on local variables.

关键词： bypass transition intermittency SST turbulence model.

Modelling overall particle motion in fluidised beds for top-spray coating processes

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Particuology 2013年第5期11卷 490-505页

作者： Mike Vanderroost Frederik Ronsse koen Dewettinck Jan G.Pietersa Department of Biosystems Engineering Ghent UniversityCoupure links 6539000 GhentBelgium Laboratory of Food Technology and Engineering Ghent UniversityCoupure links 6539000 GhentBelgium

A mathematical model predicting the overall particle motion in liquid-sprayed gas-solid fluidised beds has been developed. The proposed model is a superposition of bubble-induced particle motion and particle random walk. The model was validated using experimental particle residence times from literature. Good agreement between experimental and model-predicted residence times was obtained for those cases where atomisation air was absent and on the condition of the inclusion of a so-called ＂dead zone＂. The ＂dead zone＂, being a region of stagnant particles in the annular bottom part of the bed, has also been previously reported in literature. In case atomisation air was present, a less favourable agreement was seen between the model and the experiment. As the atomisatinn air has been shown to significantly alter the ejection distance of particles in the freeboard, recalibration of the ejection height parameter has been demonstrated to obtain an acceptable agreement between model-predicted and experimental data.

关键词： Fluidized bed coatingParticLe residence timeMathematical modelSimulationParticle motion

Application of a k-ε Model to Heat Transfer in Impinging Flows

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Journal of Thermal Science 2004年第1期13卷 62-66页

作者： Bart Merci Chris De Langhe koen Lodefier Erik Dick Ghent University Dept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgiumGhent UniversityDept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgiumGhent UniversityDept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgiumGhent UniversityDept.of FlowHeat and Combustion MechanicsSint-Pietersnieuwstraat 41B-9000 GentBelgium

Local heat transfer is predicted in turbulent axisymmetric jets, impinging onto a flat plate. A non-linear k-e model is used, in which both the constitutive law for the turbulent stresses and the transport equation for the turbulent dissipation rate e have an important contribution in the improved heat transfer predictions. The shape of the Nusselt number profiles, expressing dimensionless heat transfer, as well as the stagnation point value, are well predicted for different distances between the nozzle exit and the plate. Accurate flow field predictions are the basis for good heat transfer predictions. For a fixed Reynolds number, the influence of the nozzle-plate distance is well captured. For a fixed distance, the influence of the Reynolds number is correctly reproduced. Comparisons are made to a low-Reynolds standard k-e model and the v2-f model. A thorough discussion is found in [4]. Only a summary of those results is discussed here, while some new results are also presented.

关键词： local heat transfer impinging jets non-linear k-ε model.

Modelling the bed characteristics in fluidised-beds for top-spray coating processes

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Particuology 2012年第6期10卷 649-662页

作者： Mike Vanderroost Frederik Ronsse koen Dewettinck Jan G.Pieters Department of Biosystems Engineering Ghent UniversityCoupure links 6539000 GhentBelgium Laboratory of Food Technology and Engineering Ghent UniversityCoupure links 6539000 GhentBelgium

A particle sub-model describing the bed characteristics of a bubbling fluidised bed is presented. Atomisation air, applied at high pressures via a nozzle positioned above the bed for spray formation, is incorporated in the model since its presence has a profound influence on the bed characteristics, though the spray itself is not yet considered. A particle sub-model is developed using well-known empirical relations for particle drag force, bubble growth and velocity and particle distribution above the fluidised-bed surface. Simple but effective assumptions and abstractions were made concerning bubble distribution, particle ejection at the bed surface and the behaviour of atomisation air flow upon impacting the surface of a bubbling fluidised bed, The model was shown to be capable of predicting the fluidised bed characteristics in terms of bed heights, voidage distributions and solids volume fractions with good accuracy in less than 5 min of calculation time on a regular desktop PC. It is therefore suitable for incorporation into general process control models aimed at dynamic control for process efficiency and product quality in top-spray fluidised bed coating processes.

关键词： Fluidised bed Modelling Voidage distribution Fluidised bed characteristics Multiphase flow Coating process

SIZE MATTERS:PITCH DIMENSIONS CONSTRAIN INTERACTIVE TEAM BEHAVIOUR IN SOCCER

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Journal of Systems Science & Complexity 2013年第1期26卷 85-93页

作者： FRENCKEN Wouter VAN DER PLAATS Jorrit VISSCHER Chris LEMMINK koen University Medical Center Groningen University of GroningenCenter for Human Movement Sciences Hanze University of Applied Sciences School of Sports Studies Football Club Groningen

Pitch size varies in official soccer matches and differently sized pitches are adopted for tactical purposes in small-sided training games. Since interactive team behaviour emerges under constraints, the authors evaluate the effect of pitch size （task） manipulations on interactive team behaviour in small-sided soccer games. Four 4-a-side （plus goalkeepers） small-sided games were played： a reference game （30×20 m）, length manipulation （24×20 m）, width manipulation （30×16 m）, and a combina- tion （2× 16 m）. Using position data （100Hz）, three measures quantifying the teams＇ interaction were calculated： longitudinal inter-team distance, laterM inter-team distance, and surface area difference. Means and standard deviations, correlations and coupling values were calculated. Running correlations were calculated over a 3-s window to evaluate interaction patterns. As expected, a shorter pitch results in smaller longitudinal inter-team distance, lateral inter-team distance decreased for narrow pitches, and smaller total playing area resulted in decreased surface area. Unanticipated, a crossover effect was present; length and width manipulations also triggered changes in lateral and longitudinal direction respectively. Inter-team distances and surface area difference differed significantly across conditions. Interaction patterns differed across conditions for all measures. So, highly tactically relevant, soccer teams seem to adapt their interactive behaviour according to pitch size in small-sided gaines.

关键词： Constraints dynamics performance analysis small-sided games tactics.

Study on Pollution Cost Control Model under Asymmetric Information Based on Principal Agent

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Journal of Systems Science and Information 2021年第5期9卷 549-557页

作者： Lina WANG koen MILIS Stephen POELMANS School of Economics and Management Hainan Normal UniversityHaikou 571158China Campus Vesta Education Management IndustryBrusselsBelgium Faculty of Economics and Management Hogeschool-Universiteit BrusselKULeuven AssociationWarmoesberg 26Brussel 1000Belgium

Pollution cost control is key to solve pollution *** paper takes pollution control cost of pollution control contract between management authority and pollutant discharge enterprise as research object,considers pollution control quality level,pollution control quality inspection and pollution control cost model,and establishes pollution control cost model of management authority and pollutant discharge enterprise,including rational constraints of pollutant discharge *** it analyzes principal-agent relationship between the two under condition of asymmetric information,and un-observability of pollution control level is shown as hiding information of sewage *** essence,it is problem of adverse selection in *** control cost of management is objective *** first order condition of pollution control cost of sewage enterprise is transformed into state space equation,and optimal control of problem is solved by using maximum *** particular,management authority,as principal,uses pollution control provisions to reward,punish and encourage pollutant discharge enterprises as agents.

关键词： principal agent asymmetric information pollution cost control

Development of polymer–fullerene solar cells

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National Science Review 2016年第2期3卷 222-239页

作者： Fengling Zhang Olle Ingans Yinhua Zhou koen Vandewal Biomolecular and organic electronics Department of PhysicsChemistry and Biology(IFM)Linkoping University Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Institut fr Angewandte Photophysik Technische Universitt Dresden

Global efforts and synergetic interdisciplinary collaborations on solution-processed bulk-heterojunction polymer solar cells(PSCs or OPVs) made power conversion efficiencies over 10%*** rapid progress of the field is credited to the synthesis of a large number of novel polymers with specially tunable optoelectronic properties,a better control over the nano-morphology of photoactive blend layers,the introduction of various effective interfacial layers,new device architectures and a deeper understanding of device *** will review the pioneering materials for polymer-fullerene solar cells and trace the progress of concepts driving their *** discuss the evolution of morphology control,interfacial layers and device structures fully exploring the potential of photoactive *** order to guide a further increase in power conversion efficiency of OPV,the current understanding of the process of free charge carrier generation and the origin of the photovoltage is summarized followed by a perspective on how to overcome the limitations for industrializing PSCs.

关键词： polymer-fullerene solar cells electron donors and acceptors morphology interfacial layer device physics

SCM Implementation Decisions Under Asymmetric Information: An Agency Approach

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Journal of Systems Science and Information 2020年第5期11卷 447-457页

作者： Lina WANG Stephen POELMANS koen MILIS School of Economics and Management Hainan Normal UniversityHaikou 571158China Faculty of Economics and Management Hogeschool-Universiteit BrusselKU Leuven AssociationWarmoesberg 261000 BrusselsBelgium Campus Vesta Education Management IndustryBrusselsBelgium

The optimization investment policy decision of SCM-supply chain management-implementation has been analysed under symmetric and asymmetric information *** both conditions,SCM implementation optional decision optimizing models have been *** these models,both clients and vendors try to pursue their own *** upon the principal-agent theory,the models show to what extent a principal(a client)needs to pay more to an agent(a vendor)in a context of asymmetric *** the client it is important to understand the extra costs to be able to adopt effective strategies to stimulate a vendor to perform an optimal implementation of a SCM *** results of a simulation experiment regarding SCM implementation options illustrate and verify the theoretical findings and confirm the general notion that the less informed party is obliged to pay information rent to the better-informed party.

关键词： SCM implementation problems asymmetric information implementation control cost evaluation level principal-agent theory