Preliminary Numerical Modeling Research Articles

Preliminary Numerical Modelling of a Dynamic Spring-Mounted Wing System to Reduce the Drag of Vehicles at Higher Speeds

The dynamic behaviour of a spring-mounted symmetrical NACA0012 wing in a freestream flow of air is studied in the pre-stall region, over 0° to 12° angles of incidence. The primary aim of this work is for use within the automotive sector to reduce drag and fuel emissions. However, this work will also be of interest in the motorsport sector to improve performance, and also have some applications within the aerospace and renewable energy sectors. The general operation of the concept has previously been verified at these low angles in the pre-stall region with that of a theoretical estimation using finite and infinite wings. This paper provides a numerical solution of the same problem and is compared with the previous experimentation. At these low angles, the computations yield a dynamic response settling into a static equilibrium. The stable solutions match the start of a steady regime well, when compared with the experiment. The trends are also comparable with the experiment, but the velocities at which they occur are underestimated in the computation. The computations demonstrate a drag reduction of 59% when compared to a fixed wing, whereas the lift remains stable at a near constant value with increasing wind speed. Thence, downforce is maintained whilst drag is reduced, which will facilitate higher speeds on the straight whilst maintaining vehicle direction stability. Limitations to this proof-of-concept work are highlighted and future development work is suggested to achieve even further increases in performance.

Results of Remote Monitoring of Methane Concentration in the Air of Western Siberia Using the On-board Infrared Lidar Complex

The description of the developed infrared on-board differential absorption lidar for measuring methane content in the air was presented. The lidar was installed on board of aircraft-laboratory Tu-134 "Optic". Flight tests of the developed lidar and experimental measurements of methane concentration along the vertical routing were carried out in the summer atmosphere of mid-latitudes. Lidar measurements of methane content in the air were analyzed. They were compared with local measurements from the gas analyser installed on board of aircraftlaboratory and the results of preliminary numerical modelling. It was concluded that the on-board lidar can measure methane concentration within background values in the mid-latitude summer atmosphere.

STABILITY AND RELIABILITY OF LONG-SPAN BRIDGE STRUCTURES

Introduction: Despite the fact that, in recent years, the construction of long-span bridges has been extensively developed, cases of bridge structures buckling in wind still occur, but the issue of their interaction with wind has not been sufficiently studied. Purpose of the study: We aimed to improve the structural integrity and operational safety of long-span bridge structures by conducting a computational and experimental study on the effect of various designs of aerodynamic dampers on the aerodynamic stability of such structures. Methods: The study was performed in two stages. At the first stage, preliminary two-dimensional numerical modeling was conducted to study the effect of various designs of aerodynamic dampers on the wind flow over selected bridge spans. Based on the results of the preliminary two-dimensional numerical modeling, we chose the most effective designs of aerodynamic dampers and made their models to conduct experimental studies on aerodynamic stability on a special test bench. Results: Based on the obtained computational and experimental results, we analyzed the effectiveness of various designs of aerodynamic deflectors and fairings used to improve the aerodynamic stability of the standard bridge structure under consideration. Discussion: For a span with one main girder, we determined the deflector design that reduces the vibration amplitude at high wind velocities.

Physico-mathematical apparatus for numerical modelling of feed expander

The productivity of the feed preparation line and its technical and economic efficiency are affected by the design and technological parameters of the equipment. The geometry of the expander screw and its operating modes are no exception. To reduce the specific energy consumption of the expander, it is necessary to establish its rational design and operating parameters. This can be done using analytical calculation methods that consider the mechanisms of movement and destruction of solid substances. Modelling using the discrete element method is becoming increasingly common to describe the movement of solid components in granulators, extruders, or expanders. The purpose of the study is to improve the physical and mathematical apparatus of movement of solid feed components in the screw channel of the feed expander and develop a method for its numerical modelling. Numerical modelling was performed using a model of the movement of a multiphase Euler mixture with a split flow in three-dimensional space. In this case, the motion was subject to an admissible two-layer k-ε model of turbulence and the multiphase equation of state. The physical and mathematical apparatus for the movement of solid feed components in the screw channel of the feed expander was improved, which is the basis for the numerical modelling technique in the Star-CCM+ software suite, based on the fact that the conglomerate of feed components is represented as a package of spherical particles. In this case, the pressure force must be compensated by the total force of contact interaction of particles with each other and the wall. Preliminary numerical modelling of the process of expanded feed preparation was performed in the Star-CCM+ software suite. The practical significance lies in the fact that the improved physical and mathematical apparatus and the developed method of numerical modelling of the feed expander operation process allow substantiating its design and regime parameters to ensure low specific energy consumption without losing the quality of the technological process

Evaluation of the efficiency of aerodynamic dampers based on preliminary numerical modeling

The article is devoted to the issues of ensuring the stability of large-span bridge structures by means of their aerodynamic damping. Aerodynamic damping allows you to change the nature of the wind flow around structures or their individual elements, which can significantly reduce the loads that cause the occurrence of various aeroelastic phenomena. Aerodynamic damping devices (fairings, deflectors) are based on the phenomenon of changes in the circulation of the wind flow around the structure, the purpose of their use, as a rule, is to disrupt regular vortex formation. The main problem when using these devices is the lack of recommendations for their selection and the need for costly experimental studies to assess their effectiveness for each specific bridge. One of the ways to reduce the time and cost of research is preliminary numerical modeling in specialized software systems. Within the framework of this study, the most common types of aerodynamic dampers have been analyzed, and typical designs of large-span beam bridges have been selected. For the selected structures, a preliminary numerical simulation was carried out in a two-dimensional formulation. Based on the results obtained, the most effective designs of deflectors and fairings were determined.

Plastic Shaping of Concentrator-Waveguide Tip for Ultrasound Endovascular Ablation

One of the most effective methods of treating intravascular formations at present is the use of stepped ultrasonic waveguide systems of a tubular type (concentrators-waveguides) with a hollow spherical tip, the presence of which makesit possible to supply liquid media to the dislocation zone of an intravascular formation with the aim of additional cavitation effect and as efficiently as possible. destroy intravascular formations due to vibration impact. Based on the results of the analysis on the features of the existing shaping methods for obtaining a hollow spherical tip of the concentrator-waveguide, it is advisable to use methods of plastic deformation – expansion and crimping. The paper presents results of preliminary calculations, numerical modeling and experimental studies of tip shaping processes of the concentrator-waveguide by distribution and crimping. On the basis of the finite element method in the environment of the ABAQUS software package, modeling of the expansion and crimping of a pipe billet was carried out, which has made it possible to: evaluate the stress-strain state of the deformable conical section of the billet, the change in wall thickness during the forming process and calculate the length of the billet for the design of the conical section; to establish the patterns of the influence of geometric parameters on the power modes of the distribution process; to set the parameters of the modes of forming the tip of the concentrator-waveguide by the method of distribution and crimping, which ensure the formation of the required geometry. The obtained results of preliminary calculation, numerical modeling and experimental studies of tip shaping processes of the concentrator-waveguide by distribution and crimping have similar values, which confirms the correctness of using both the method of preliminary calculation and numerical modeling in the development of the technology for manufacturing the concentrator-waveguide.

Corrosion of cast iron pipelines buried in Fraser River silt subject to climate-induced moisture variations

Experiments were carried out to characterise the influence of soil water retention properties on the corrosion of a cast iron specimen buried in Fraser River silt. The corrosion rates were measured at different degrees of saturation using standard corrosion tests, along with separate water retention tests for the Fraser River silt. Building on previous work on this topic, a numerical model solving moisture flow, oxygen diffusion, electrical conductivity and their coupled influence on metallic corrosion in unsaturated soil was developed. The experimental data and preliminary numerical modelling results were then used as inputs to a field-scale numerical model to examine climate-induced moisture migration around a pipeline and the resulting levels of corrosion. The time-dependent corrosion mass loss and the resulting loss in pipe wall thickness of a buried pipeline were modelled, and it was demonstrated that the cyclic climatic variations predominantly perturb the corrosion rates during the initial cycles, and subsequently a gradual corrosion rate arises depending on general climatic conditions. Further analysis of the influence of electrical resistivity on the levels of corrosion revealed that a decrease in resistivity due to effects such as seawater intrusion or naturally saline soils may result in a significant increase in the levels of localised corrosion.

Preliminary Numerical Modeling of CO2 Geological Storage in the Huangcaoxia Gas Reservoir in the Eastern Sichuan Basin, China

Depleted gas reservoirs are important potential sites for CO2 geological sequestration due to their proven integrity and safety, well-known geological characteristics, and existing infrastructures and wells built for natural gas production. The Sichuan Basin has a large number of gas fields in which approximately 5.89×109 tons of CO2 can be stored. The Huangcaoxia gas field has the best opportunity in the eastern Sichuan Basin for a pilot project of CO2 sequestration due to its relatively large storage capacity and the nearly depleted state. A coupled thermal-hydrodynamic model including faults is built based on the geological and hydrogeological conditions in the Huangcaoxia gas field. The results of the numerical simulations show that the downhole temperature is above 80°C at a downhole pressure of 14 MPa under the constraint of temperature drop in the reservoir due to the strong Joule-Thomson effect. The corresponding injection pressure and temperature at the wellhead are 10.5 MPa and 60°C, respectively. The sizes of the pressure and CO2 plumes after an injection of 10 years are 18 km and 5 km, respectively. The zone affected by temperature change is very small, being about 1-2 km away from the injection well. The injection rate in the injection well Cao 31 averages 6.89 kg/s (21.73×104 tons/a). For a commercial-scale injection, another four wells (Cao 9, Cao 30, Cao 6, and Cao 22) can be combined with the Cao 31 well for injection, approaching an injection rate of 35 kg/s (1.10×106 tons/a). Both the pressure and temperature of CO2 injection decrease with the increasing depleted pressure in the gas reservoir when the latter is below 6 MPa. With the technique of CO2-enhanced gas recovery (CO2-EGR), the CO2 injection rate is improved and approximately 1.58×107 kg of gas can be produced during a studied time period of 10 years.

Hydraulic evaluation of a dewatering scheme in shallow aquifers in Kuwait

In heavily populated residential areas lacking adequate subsurface drainage, leakage from urban water supplies and wastewater discharge causes groundwater levels in underlying shallow aquifers to rise. This may have serious consequences for the stability of building foundations, roads and natural landforms. This paper evaluates the performance of a dewatering scheme comprising of 15 vertical wells in two residential areas in Kuwait. The hydraulic effectiveness is evaluated from pumping tests and preliminary numerical modelling. The results show that the scheme can keep the water table at the desired levels over a limited area. The maximum predicted nodal drawdowns after one year of pumping at 16 835 m 3 d –1 were 4.2 and 5.24 m in the two areas. Further investigations are proposed with the objective of optimizing pumping rates.

Экспериментальное исследование пульсационных характеристик закрученного потока в модели четырехвихревой топки

Актуальность исследования обусловлена необходимостью вовлечения в топливно-сырьевую базу низкосортных высокозольных углей в связи с ограниченностью запасов высококачественного топлива. Для их эффективного и экологически безопасного использования требуется разработка новых и модернизация имеющихся котельных агрегатов с предварительным физическим и численным моделированием. Целью работы является экспериментальное исследование пульсационных характеристик турбулентного закрученного потока в модели перспективного топочного устройства, использующего четырёхвихревую схему сжигания пылеугольного топлива. Объектом исследования является изотермическая лабораторная модель четырёхвихревой топки, выполненная из оптически прозрачного оргстекла для проведения измерений в рамках современных бесконтактных методов диагностики потоков. Методы: физическое лабораторное моделирование аэродинамики и процессов переноса в четырехвихревой топке; бесконтактное исследование осредненных и пульсационных характеристик в объеме модели топки при различных режимных параметрах; исследование пульсаций давления с использованием конденсаторного микрофона. Результаты. С использованием метода цифровой трассерной визуализации получены распределения осредненных и пульсационных характеристик скорости потока в ряде сечений модели в широком диапазоне режимных параметров. Определено положение зон с высоким значением турбулентных пульсаций и застойных зон, установлены особенности их расположения в зависимости от режимов. С использованием конденсаторного микрофона получены данные о пульсациях давления в локальных областях объема модели. Анализ спектральных характеристик с применением к полученным данным преобразования Фурье показал, что в изучаемой модели отсутствуют нестационарные периодические колебания, связанные с прецессией вихревого ядра потока. Измеренные пульсации давления вызваны акустикой, пульсации скорости носят случайный характер и не связаны с динамикой когерентных структур.

Energy and mechanical aspects on the thermal activation of diaphragm walls for heating and cooling

Underground geotechnical structures, such as deep and shallow foundations, diaphragm walls, tunnel linings and anchors are being increasingly employed as energy geostructures to exchange heat with the ground by installing absorber pipes into the structural elements. This paper focuses on the application of this technology to reinforced concrete diaphragm walls used for construction of underground car parks, basements and metro stations, with the purpose of heating and cooling the adjacent buildings. Preliminary numerical modelling allowed optimising the geothermal plant design of the diaphragm wall. Then its energy efficiency is investigated through finite element thermo-hydro coupled analyses together with the effects of the thermal activation on the surrounding soil. Finally, finite difference thermo-mechanical analyses are used to study the mechanical effects induced by the thermal activation.

Design of a split Hopkinson pressure bar with partial lateral confinement

This paper presents the design of a modified split Hopkinson pressure bar (SHPB) where partial lateral confinement of the specimen is provided by the inertia of a fluid annulus contained in a long steel reservoir. In contrast to unconfined testing, or a constant cell pressure applied before axial loading, lateral restraint is permitted to develop throughout the axial loading: this enables the high-strain-rate shear behaviour of soils to be characterised under conditions which are more representative of buried explosive events. A pressure transducer located in the wall of the reservoir allows lateral stresses to be quantified, and a dispersion-correction technique is used to provide accurate measurements of axial stress and strain. Preliminary numerical modelling is utilised to inform the experimental design, and the capability of the apparatus is demonstrated with specimen results for a dry quartz sand.

Preliminary numerical modelling of CO2 gas foaming in heavy oil and simulations of oil production from heavy oil reservoirs

Basic understanding of numerical modelling for the effects of CO2 foaming on heavy oil production behaviour using the huff‐and‐puff process is relevant for CO2‐EOR performance. The numerical model was constructed based on laboratory measurements: CO2 solubility, foam swelling, and apparent viscosity. The model for unsaturated solubility in porous media, such as sandstone cores and oil reservoirs, was proposed by defining CO2 solubility in heavy oil for generating foamy oil. The foaming process was modelled with four kinds of foamy oils at discrete depressurizations below each equilibrium pressure. A numerical model of apparent foam viscosity with discrete depressurization was set up based on experimental measurements as a function of pressures and temperatures of 0.1–10 MPa and 20–50 °C. The matching between the numerical simulations of heavy oil drainage and experimental measurements of foaming in Berea sandstone cores (Psat = 10 MPa at 50 °C) shows 31 % oil recovery after depressurization to atmospheric pressure. The numerical simulation results of heavy oil production at field‐scale showed that CO2 gas production quickly increases after depressurization and then the foamy oil production increases following the peak gas production rate. In the first cycle of the huff‐and‐puff process, the maximum oil production rate ranged from 4–68 m3/day. From the sensitivity study it can be concluded that the initial oil saturation and the CO2 dissolution zone as compared with reservoir size play a main function in heavy oil production by CO2 gas foaming in the huff‐and‐puff process.

Investigation of Geomorphic and Seismic Effects on the 1959 Madison Canyon, Montana, Landslide Using an Integrated Field, Engineering Geomorphology Mapping, and Numerical Modelling Approach

We present an integrated approach to investigate the seismically triggered Madison Canyon landslide (volume = 20 Mm3), which killed 26 people in Montana, USA, in 1959. We created engineering geomorphological maps and conducted field surveys, long-range terrestrial digital photogrammetry, and preliminary 2D numerical modelling with the objective of determining the conditioning factors, mechanisms, movement behaviour, and evolution of the failure. We emphasise the importance of both endogenic (i.e. seismic) and exogenic (i.e. geomorphic) processes in conditioning the slope for failure and hypothesise a sequence of events based on the morphology of the deposit and seismic modelling. A section of the slope was slowly deforming before a magnitude-7.5 earthquake with an epicentre 30 km away triggered the catastrophic failure in August 1959. The failed rock mass rapidly fragmented as it descended the slope towards Madison River. Part of the mass remained relatively intact as it moved on a layer of pulverised debris. The main slide was followed by several debris slides, slumps, and rockfalls. The slide debris was extensively modified soon after the disaster by the US Army Corps of Engineers to provide a stable outflow channel from newly formed Earthquake Lake. Our modelling and observations show that the landslide occurred as a result of long-term damage of the slope induced by fluvial undercutting, erosion, weathering, and past seismicity, and due to the short-term triggering effect of the 1959 earthquake. Static models suggest the slope was stable prior to the 1959 earthquake; failure would have required a significant reduction in material strength. Preliminary dynamic models indicate that repeated seismic loading was a critical process for catastrophic failure. Although the ridge geometry and existing tension cracks in the initiation zone amplified ground motions, the most important factors in initiating failure were pre-existing discontinuities and seismically induced damage. Amplification played a secondary role.

Experimental and numerical investigations on structured catalysts for methane steam reforming intensification

Hydrogen production for green energy purposes arouses attention of industrial and scientific research. Despite a growing interest towards distributed hydrogen production, difficulties due to the heat and mass transfer limitations in the steam reforming processes reduces the possibility of small scale plants, and dramatically increases fixed and operative costs. Highly thermal conductive honeycomb structures were proposed as catalyst supports for hydrogen-rich stream production by methane steam reforming to enhance the heat and material transfer properties of catalysts, in order to increase the process sustainability. This work focuses on the experimental testing and preliminary numerical modeling of the methane steam reforming reaction performed on a Nickel-loaded silicon carbide monolith packaged into an externally heated tube. In particular, the two flow configurations of Flow Through and Wall Flow were investigated and compared, the impact of a washcoat deposition was evaluated. The wall-flow catalytic configuration is an innovative solution in the reforming processes, no examples were reported in the literature. A preliminary steady-state heterogeneous 3D model was developed including momentum, mass and energy balances. The experimental tests as well as the numerical simulations indicate that the Wall Flow configuration may overcome the fixed-bed reactor problems, yielding a more uniform temperature distribution and more effective mass transport. The highly conductive supports in wall-flow configuration appeared so able to minimize typical reforming processes limitations, improving the overall catalytic system kinetics and so resulting in an appreciable process intensification.

Harpoon technology development for the active removal of space debris

This paper presents the results of preliminary empirical testing and numerical modelling carried out to demonstrate the effectiveness of using a harpoon in an ADR application. Empirical testing involving the impact of blunt and conical shaped steel tips into 3mm Al plate showed that the ballistic limit varies in proportion to the tip circumference, with conical shapes resulting in a higher relative ballistic limit due to the additional energy required for petaling. The creation of secondary debris was also monitored. It was found that blunt shapes created a plug during penetration as a result of shearing around the periphery of the projectile, whilst conical tips resulted in minor spalling and fragmentation. Preliminary oblique impact testing with conical and blunt tips showed that the ballistic limit increases with obliquity at a greater rate for blunt tips than conical ones.Impact testing of 3mm Al plate with conical projectiles at low temperatures showed a more brittle fracture mode when compared with targets impacted at room temperature. As such, the fragmentation and spalling evident in room temperature targets was absent. The energy required to perforate the cooled plates also increased.Impact testing of Al panel obstructed with fixed heat pipes showed that the harpoon could successfully penetrate a target panel with such an obstruction due to shearing of the pipe flange.Testing of two lock on mechanisms showed that both a spring activated and integrated toggle could reliably open upon impact. This testing also used a tensile testing machine to show that both designs could withstand the force expected during deorbiting manoeuvres after impact with Al H/C panels.A parametric simulation comparing the diameter of conical tips with ballistic limits showed a good agreement with the predictions of De Marre’s formula for normal impact. This suggests that the ballistic limit of plates impacted by conical projectiles can be successfully extrapolated with limited experimental data. A SPH solver, which is better suited to modelling impact into brittle materials, was used to model impact into CFRP targets. This showed that the debris formed by conical tips was less coherent and had a higher terminal velocity than that produced by blunt tips. As a result of conducting these simulations, it was shown that numerical modelling can provide an accurate prediction of impact speeds required for a conical projectile to perforate Al plate, excellent prediction of impact failure modes, and good predictions of debris likely to be created during the impact process.Finally, preliminary studies of harpoon impact into low mass targets with up to 3 DOF showed that the harpoon was still able to penetrate such targets under simulated μ-gravity conditions.

Monolithic catalysts for methane steam reforming intensification: Experimental and numerical investigations

Highly thermal conductive honeycomb structures were proposed as catalyst supports to enhance the heat and material transfer properties of catalysts. This work focuses on the experimental testing and preliminary numerical modeling of the methane steam reforming reaction performed on a Ni-loaded SiC monolith packaged into an externally heated tube. In particular, the two flow configurations of flow through and wall flow were investigated and compared. A preliminary steady-state heterogeneous 3D model was developed including momentum, mass and energy balances. The experimental tests as well as the numerical simulations indicate that the wall flow configuration may overcome the fixed-bed reactor problems, yielding a more uniform temperature distribution and more effective mass transport.

Preliminary Results from the Experimental Study of CO2-Brine-Rock Interactions at Elevated T & P: Implications for the Pilot Plant for CO2 Storage in Spain

A new experimental program has been carried out in order to study CO2-brine-rock interactions susceptible to take place in conditions close to those expected in the pilot plant that is being developed in Spain (a carbonate reservoir located at more than 800 m depth, with 15% porosity, and a salinity of the native brine between 20 – 90g/L). The combination of preliminary experimental and numerical modeling (PHREEQC) results suggests that the main geochemical processes are calcite dissolution and anhydrite precipitation.

A NUMERICAL MODEL OF THE LASER LIGHT INTENSITY TRANSVERSAL DISTRIBUTION INTO UNDEFORMED/DEFORMED OPTICAL FIBERS

Preliminary results obtained in developing a numerical model of laser light intensity transverse distribution into undeformed/deformed step index optical fiber are presented. The main purpose of the presented preliminary numerical modelling results consists in developing a simple method of fiber optical sensors interrogation, especially concerning strain and pressure measurements. It is a potential important matter for aeronautical research and industry because of the more extended use of fibre optic sensors in aircraft manufacturing. The developed numerical model relies on solving the equations of electromagnetic waves propagation into optical fibers by using the finite element method technique (FEM). The results of numerical simulation obtained by considering single mode or multimode and various laser wavelengtsh are presented. One important achievement reported in this paper consists in preliminary experimental results concerning the modification of laser intensity transverse distribution observed for multimode optical fiber with and without perpendicular mechanical load. The reported preliminary experimental results confirm to some extent the predictions of numerical simulations regarding laser intensity distribution under low and medium transverse mechanical load. One important conclusion of this paper consists in the future development of fiber optic sensor interrogation techniques based on the reported preliminary experimental and numerical simulation results.

Attentional modulation of the tuning of neurons in area MT to the direction of transparent motion

Event Abstract Back to Event Attentional modulation of the tuning of neurons in area MT to the direction of transparent motion Anja Lochte1*, Valeska Stephan1, Vladislav Kozyrev1, 2, Annette Witt2, 3 and Stefan Treue1 1 German Primate Center, Germany 2 Bernstein Center for Computational Neuroscience, Germany 3 Max Planck Institute for Dynamics and Self-Organization , Germany Transparent motion perception requires the segmentation and separate representation of multiple motion directions within the same part of visual space. In a previous study we recorded responses from direction-selective neurons in macaque middle temporal area (MT) to unattended bidirectional random dot patterns (RDPs; Treue et al., 2000). The profile of responses to such transparent motion patterns is the scaled sum of responses to the individual components, showing two peaks when the angle between the component directions exceeds the neuron’s tuning width.Here we investigated the influence of attention on the representation of the direction components of transparent motion by recording from MT in an attentional paradigm. Our question was, whether the effects of attention can be better characterized as a modulation of the population response in MT or as a modulation of two independent neuronal populations, each encoding one of the two directions (as might be expected to happen in area V1). Two monkeys were trained on a task, where an initial cue indicated the relevant direction of motion in a given trial. Two RDPs were then presented, moving within a common stationary aperture, sized and positioned to fit within the classical receptive field. While maintaining gaze on a fixation point, the animals were instructed to respond to a speed increment within the cued surface. In a sensory condition, the monkeys were asked to respond to a luminance change of the fixation point. By systematically varying the overall pattern direction, tuning curves were measured with a constant relative angle of 120 degrees between the component directions. The activity profile across 90 MT units showed two peaks corresponding to the two stimulus configurations in which one of the directions moved in the neuron’s preferred direction. The profile can be well fit by the sum of two Gaussians, enabling a quantitative comparison of neuronal responses for the attended versus the sensory condition. The fitted tuning curves showed an average increase of 52% around the peak where the preferred direction was attended relative to the sensory condition. For the peak corresponding to the condition when the preferred direction was unattended, we observed an average suppression of 5%. Neither of the fitted individual Gaussians showed a change in tuning width. Our results, supported by preliminary numerical modeling, show that attending to one surface in a transparent motion stimulus causes a direction-dependent modulation of the population response in MT, representing the neural correlate of attentional allocation to an individual surface.Acknowledgments: The project was supported by the Volkswagen Foundation (grant I/79868) and by grant 01GQ0433 from the Federal Ministry of Education and Research to the Bernstein Center for Computational Neuroscience Goettingen. Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Poster Presentation Topic: Sensory processing Citation: Lochte A, Stephan V, Kozyrev V, Witt A and Treue S (2009). Attentional modulation of the tuning of neurons in area MT to the direction of transparent motion. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.154 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Aug 2009; Published Online: 28 Aug 2009. * Correspondence: Anja Lochte, German Primate Center, Göttingen, Germany, alochte@gwdg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue Google Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue Google Scholar Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue PubMed Anja Lochte Valeska Stephan Vladislav Kozyrev Annette Witt Stefan Treue Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.