Global design of hydraulic structures optimised with physically based flow solvers on multiblock structured grids

peer reviewedThis paper presents the numerical studies lead by the Laboratory of Applied Hydrodynamics and Hydraulic Constructions of the University of Liège (HACH) for the rehabilitation of the 21-meter high Nisramont dam in Belgium. After determination of the up-to-date 1000-year return flood using the hydrological runoff model WOLFHYDRO on the global 74,000 ha watershed real topography coupled with statistical analyzes, and after validation on the existing situation and for extreme observed events, the 2D finite volume multiblock flow solver WOLF2D has been applied to the design of the new stilling basin and to the bottom outlet rehabilitation impact study. The multiblock solver possibilities allow mesh refinement close to interesting areas, such as dam spillway and stilling pool, without leading to prohibitive CPU times, while suitable shallow water equations formulation allows the computation of the flows on the strongly vertically curved bottom of the spillway. In the described simulation, 270,000 structured finite volumes, from .25 to 1 meters long, are used to simulate as a whole the flows in the upstream reservoir, dam, spillway, stilling basin and downstream river, this on a real topography

Large scale 2D numerical modelling of reservoirs sedimentation and flushing operations

peer reviewedaudience: researcherThe quasi-3D flow solver WOLF has been developed at the University of Liege for almost a decade. It has been used to carry out the simulation of silting processes in large reservoirs and to predict the efficiency of flushing operations. Besides briefly depicting the mathematical and numerical model, the present paper demonstrates its applicability on the case of a large hydropower project in India. The silting process of the reservoir has been simulated by means of the quasi-3D flow model with a quasi-steady approach. For simulating flushing events, both the topography changes and their interactions with the flow have been carefully handled in a strongly coupled approach. This narrow coupling has required the development of a suitable upwind numerical scheme. Results are presented with 2D- and 3D-views, completed by cross-sections and curves of the variation of key variables. The numerous observations based on those results lead to a global assessment of the silting mechanism and of the flushing efficiency

New Fluorinated 1,2,4-Benzothiadiazine 1,1-Dioxides: Discovery of an Orally Active Cognitive Enhancer Acting through Potentiation of the 2-Amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic Acid Receptors

In the search of a potent cognitive enhancer, a series of 3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxides have been synthesized and evaluated as positive allosteric modulators of the AMPA receptors. In the present work, we focused our efforts on the insertion of mono- or polyfluoro- substituted alkyl chains at the 4-position of the thiadiazine ring in an attempt to enhance the pharmacokinetic behavior of previously described compounds. Among all the described compounds, 7-chloro-4-(2-fluoroethyl)-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide, 12b, was shown to exert a strong activity on AMPA receptors in vitro and a marked cognitive-enhancing effect in vivo after oral administration to Wistar rats. Considering its in vivo activity, the metabolic degradation of 12b was studied and compared to that of its nonfluorinated analogue 9b. Taken together, results of this study clearly validated the positive impact of the fluorine atom on the alkyl chain at the 4-position of benzothiadiazine dioxides on activity and metabolic stability

Autonomous space exploration using the Turtlebot mobile platform

Cilj diplomske naloge je implementacija avtonomnega raziskovanja prostora na mobilni platformi Turtlebot, ki uporablja razvojno okolje ROS. Implementirali smo raziskovalni algoritem, ki temelji na zaznavi obrobij in njihovi uporabi kot potencialnih raziskovalnih ciljev. Ker pa lahko algoritem pri izbiri raziskovalnih ciljev upošteva različne kombinacije ocen raziskovanja, smo nato preizkušali in primerjali, katera kombinacija ocen omogoča najbolj učinkovito raziskovanje prostora. Različne strategije izbire raziskovalnih ciljev smo ocenjevali in primerjali na podlagi štirih kriterijev ter referenčne strategije, ki naključno izbira raziskovalne cilje. Podatke za primerjavo smo dobili tako, da smo za vsako strategijo opravili deset uspešnih raziskovanj. Te smo nato kot skupine povprečnih vrednosti in odstopanj primerjali med seboj na podlagi referenčne strategije in kriterijev. Implementirali smo modul, ki poleg raziskanosti prostora in časa raziskovanja omogoča tudi beleženje zgodovine premikov in s tem pot raziskovanja, ki jo opravi Turtlebot.The purpose of this undergraduate thesis is to implement the autonomous exploration of space on the Turtlebot mobile platform that uses the ROS development environment. We implemented an exploration algorithm based on the detection and use of frontier regions as potential exploration goals. Since the algorithm is able to choose an exploration goal based on the combination of different assessments, we tested and compared which combination of goal assessments enables the most efficient exploration of a given space. We assessed and compared different strategies of goal setting on the basis of four criteria and a referential strategy which selects its exploration goals randomly. In order to get the data necessary for comparison, we conducted ten successful explorations per strategy and compared them on the basis of the referential strategy and criteria. We implemented our own module, which tracks the amount of space explored and the time spent for exploration, while also documenting the path traveled by the Turtlebot during exploration

Exploring thienothiadiazine dioxides as isosteric analogues of benzo-and pyridothiadiazine dioxides in the search of new AMPA and kainate receptor positive allosteric modulators

peer reviewedThe synthesis and biological evaluation on AMPA and kainate receptors of new examples of 3,4-dihydro-2H-1,2,4-thieno[3,2-e]-1,2,4-thiadiazine 1,1-dioxides is described. The introduction of a cyclopropyl chain instead of an ethyl chain at the 4-position of the thiadiazine ring was found to dramatically improve the potentiator activity on AMPA receptors, with compound 32 (BPAM395) expressing in vitro activity on AMPARs (EC2x = 0.24 μM) close to that of the reference 4-cyclopropyl-substituted benzothiadiazine dioxide 10 (BPAM344). Interestingly, the 4-allyl-substituted thienothiadiazine dioxide 27 (BPAM307) emerged as the most promising compound on kainate receptors being a more effective potentiator than the 4-cyclopropyl-substituted thienothiadiazine dioxide 32 and supporting the view that the 4-allyl substitution of the thiadiazine ring could be more favorable than the 4-cyclopropyl substitution to induce marked activity on kainate receptors versus AMPA receptors. The thieno-analogue 36 (BPAM279) of the clinically tested S18986 (11) was selected for in vivo evaluation in mice as a cognitive enhancer due to a safer profile than 32 after massive per os drug administration. Compound 36 was found to increase the cognition performance in mice at low doses (1 mg/kg) per os suggesting that the compound was well absorbed after oral administration and able to reach the central nervous system. Finally, compound 32 was selected for co-crystallization with the GluA2-LBD (L504Y,N775S) and glutamate to examine the binding mode of thienothiadiazine dioxides within the allosteric binding site of the AMPA receptor. At the allosteric site, this compound established similar interactions as the previously reported BTD-type AMPA receptor modulators

Modelling of the wave propagation, the coastal currents and the induced topographic changes

peer reviewedThis paper models the sea bottom evolution. This model is built up on three main parts. The first one describes the wave propagation, taking simultaneously into account the refraction, the diffraction and the reflection but also the energy dissipation caused by wave breaking. This model is solved by the numerical method of the finite volumes, using an iterative resolution (the GMRES method). Several validations of this model have been carried out on many examples such as harbors of various geometries and depths, beaches,… The wave induced currents are computed in the second part based on the concept of the radiation stresses describing the excess of the flux momentum caused by the waves. A model based on the complete Navier-Stokes equations integrated on the depth and associated with appropriated forcing and friction terms is used. This model is computed as an update of WOLF software (HACH, ULg) and is applied to some examples such as beaches with or without coastal structures. Finally, the third part is about the sediment transport. It exhibits the topographic modifications of the coastal sea bottom caused by the waves and their currents. A loop execution of these three models ends this work. It gives us an operational tool to describe the topographic evolution of the coastal areas caused by the incident waves, the induced currents and then the resulting sediment transport, fulfilling the objectives of this paper

INFLUENCE OF SLUDGE CONDITIONING AND DEWATERING ON CONVECTIVE DRYING AT INDUSTRIAL SCALE

FRFC. 2.4596.12– 2012 and FNRS-EQUIP U.N037.1

Scale modelling and similarity laws for the study of an under pressure settling structure

peer reviewedThis paper presents the scale model studies of a complex under pressure settling structure, carried out at the Laboratory of Hydraulic Constructions of the University of Liège. Made up of fourteen identical settling chambers placed side by side and the bottom of which is divided into pyramidal hoppers, the structure, totally under pressure, is fed by a vertical shaft. Downstream, the settling chambers discharge into a collector, which ensures the clean water feeding of four penstocks through a free surface basin. Finally, a pipes network, under the chambers, ensures the downstream evacuation of the sand trapped in the hoppers. Using adapted and theoretically justified similarity laws coupled with realistic scales for the models, the hydrodynamic behavior and solid transport phenomena in this complex system have been studied. Special care has been taken to evaluate the trap efficiency, the evacuation system working and the global discharge repartition between the fourteen chambers. Sawdust, plastic balls or very small sand particles have been used to model real sediments. A total of three models, from only one hopper to the full settling structure, have been built, with scales from 1/18.5 to 1/100. According to the results of the studies, the length of the settling chambers has been shortened of up to 38 meters, i.e. 2 hoppers, and best use instructions have been suggested for the sediment evacuation system