Articles de revues : « Immersed object »

1

Jarlan, G. E. « MODEL STUDY OF AN ISOLATED LIGHTHOUSE PLATFORM AT SEA (PRINCE SHOAL, QUEBEC) ». Coastal Engineering Proceedings 1, n^o 7 (29 janvier 2011) : 43. http://dx.doi.org/10.9753/icce.v7.43.

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Experiments on objects subject to wave forces have been made in the past, which led to formulae where the geometrical characteristics of the object are of primary importance. Other experiments, made on immersed objects, showed that the accelerative forces caused by wave impact are of the same order of magnitude as the drag forces associated with orbital velocities. In the case of a small free body completely immersed in a fluid and subject to a system of forces, other experiments showed that the fluid surrounding the body acquires a velocity while the flow field gains kinetic energy (Bef. 1). The acceleration of the object can be deduced from the pressure distribution around the body.

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Liu, Cheng, et Changhong Hu. « An efficient immersed boundary treatment for complex moving object ». Journal of Computational Physics 274 (octobre 2014) : 654–80. http://dx.doi.org/10.1016/j.jcp.2014.06.042.

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Jahangiri, Ali, et Mojtaba Biglari. « The stability of vapor film immersed in superfluid helium on the surface of the hot ball ». Proceedings of the Institution of Mechanical Engineers, Part E : Journal of Process Mechanical Engineering 230, n^o 6 (3 août 2016) : 433–39. http://dx.doi.org/10.1177/0954408914559571.

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In this article, the evolution of vapor film on the surfaces of hot objects immersed in a cryogenic superfluid helium liquid is considered. It is assumed that at the beginning of the process, a thin film of steam exists on the surface of the object that has a spherical shape. If the heat flux is greater than the critical heat flux, the growth of vapor film will continue, otherwise it will collapse. Survey and analysis of the previously mentioned problem has been done using numerical method and the main onjectives are as follows: (a) study the evolution of the vapor film immersed in superfluid helium on the surface of the hot ball and (b) the stability of vapor film immersed in superfluid helium on the surface of the hot ball.

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Chern, Ming-Jyh, Dedy Zulhidayat Noor, Ching-Biao Liao et Tzyy-Leng Horng. « Direct-Forcing Immersed Boundary Method for Mixed Heat Transfer ». Communications in Computational Physics 18, n^o 4 (octobre 2015) : 1072–94. http://dx.doi.org/10.4208/cicp.151214.250515s.

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AbstractA direct-forcing immersed boundary method (DFIB) with both virtual force and heat source is developed here to solve Navier-Stokes and the associated energy transport equations to study some thermal flow problems caused by a moving rigid solid object within. The key point of this novel numerical method is that the solid object, stationary or moving, is first treated as fluid governed by Navier-Stokes equations for velocity and pressure, and by energy transport equation for temperature in every time step. An additional virtual force term is then introduced on the right hand side of momentum equations in the solid object region to make it act exactly as if it were a solid rigid body immersed in the fluid. Likewise, an additional virtual heat source term is applied to the right hand side of energy equation at the solid object region to maintain the solid object at the prescribed temperature all the time. The current method was validated by some benchmark forced and natural convection problems such as a uniform flow past a heated circular cylinder, and a heated circular cylinder inside a square enclosure. We further demonstrated this method by studying a mixed convection problem involving a heated circular cylinder moving inside a square enclosure. Our current method avoids the otherwise requested dynamic grid generation in traditional method and shows great efficiency in the computation of thermal and flow fields caused by fluid-structure interaction.

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Bušík, Martin, et Ivan Cimrák. « The calibration of fluid-object interaction in immersed boundary method ». EPJ Web of Conferences 143 (2017) : 02013. http://dx.doi.org/10.1051/epjconf/201714302013.

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Soria-Verdugo, A., L. M. Garcia-Gutierrez, S. Sanchez-Delgado et U. Ruiz-Rivas. « Circulation of an object immersed in a bubbling fluidized bed ». Chemical Engineering Science 66, n^o 1 (janvier 2011) : 78–87. http://dx.doi.org/10.1016/j.ces.2010.10.006.

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Orishchenko, Svetlana S. « Things in cinema as a phenomenon of cultural reality ». Aspirantskiy Vestnik Povolzhiya 21, n^o 3-4 (10 décembre 2021) : 73–77. http://dx.doi.org/10.17816/2072-2354.2021.21.2.73-77.

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The objects, items, things that are most often used in the film texts of modern Russian cinema require close attention from the film culture point of view. The material world helps to realize the value of an object and its influence on the subject. The attitude to things and objects characterizes modern society from the point of view of order-chaos. Contemporary domestic film texts are interpreted by specialists and spectators, intended for a wide audience of the audience. A person is immersed in a system of symbols, and in cinema he seeks confirmation of this or that stable element of the virtual world, which he correlates with his real experience. Things, objects and objects can tell about the main thing, so they cannot be ignored, pass by this or that symbolic object.

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Zhao, Xiang, Liming Yang, Chang Xu et Chang Shu. « An overset boundary condition-enforced immersed boundary method for incompressible flows with large moving boundary domains ». Physics of Fluids 34, n^o 10 (octobre 2022) : 103613. http://dx.doi.org/10.1063/5.0122257.

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Conventional immersed boundary methods (IBMs) have greatly simplified the boundary condition treatment by interpreting boundaries as forces in the source terms of governing equations. In conventional IBMs, uniform meshes of very high resolution must be applied near the immersed boundary to treat the solid–fluid interface. However, this can induce a high computational cost for simulating flows with large moving boundary domains, where everywhere along the trajectory of the moving object must be refined isotropically. In the worst scenario, a global refinement is required when the object is moving arbitrarily in the entire computational domain. In this work, an overset boundary condition-enforced immersed boundary method (overset BC-enforced IBM) is proposed to simulate incompressible flows with large moving boundary domains efficiently. In the proposed overset BC-enforced IBM, a locally refined uniform mesh is applied and fixed on the moving object to account for the local motions, e.g., the rotation and deformation of the object, while the global motion of the object is handled by embedding the locally refined mesh in a coarser background mesh. Both the local mesh and the global background mesh can be generated automatically using the Cartesian approach to avoid the cumbersome boundary treatment. Since the mesh refinement is local, considerable computational savings can be achieved. The overset BC-enforced IBM is combined with the lattice Boltzmann flux solver to simulate various fluid–structure interaction problems with rigid and deformable boundaries.

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Szabo, Thomas L. « Imaging three dimensional objects with ultrasound ». Journal of the Acoustical Society of America 152, n^o 4 (octobre 2022) : A167. http://dx.doi.org/10.1121/10.0015907.

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The ultrasound imaging laboratory provided students with the opportunity of determining what an unknown three dimensional object was from two-dimensional images. Armed with a portable diagnostic ultrasound imaging system, and internal calipers for quantification, students were given unknown objects from the creepy crawly collection. Each object was immersed in a small tub of opaque fluid. Students could adjust the imaging system to give different cross-sections or cut planes through the object. From this information and linear calipers, they were to determine what the object was and provide a quantitative three dimensional sketch. This experience gave them a taste of the chief difficulty in diagnostic imaging of the body: deciphering and recognizing tissue structures and organs from partial views. Other imaging exercises included the use of imaging phantoms to measure spatial and temporal resolution as a function of depth and other controls.

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10

Magiliotou, Maria, Ye-Mon Chen et Liang-Shih Fan. « Bed-immersed object heat transfer in a three-phase fluidized bed ». AIChE Journal 34, n^o 6 (juin 1988) : 1043–47. http://dx.doi.org/10.1002/aic.690340620.

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Chen, Sung-Hua, Yen Ku et Chao-An Lin. « Simulations of settling object using moving domain and immersed-boundary method ». Computers & ; Fluids 179 (janvier 2019) : 735–43. http://dx.doi.org/10.1016/j.compfluid.2018.09.007.

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Goh, Ker Liang. « Force on Fluid by Immersed Body — And Archimedes’ Principle ». Physics Educator 02, n^o 03 (septembre 2020) : 2020004. http://dx.doi.org/10.1142/s2661339520200048.

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Applying Newton’s third law, the action and reaction pair of the buoyant force (upthrust) when an object is immersed in a fluid is considered. A discussion follows on how this can be used to solve problems and derive Archimedes’ principle.

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You, Cheng-Shu, Ming-Jyh Chern, Dedy Zulhidayat Noor et Tzyy-Leng Horng. « Numerical Investigation of Freely Falling Objects Using Direct-Forcing Immersed Boundary Method ». Mathematics 8, n^o 9 (18 septembre 2020) : 1619. http://dx.doi.org/10.3390/math8091619.

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The fluid-structure interaction of solid objects freely falling in a Newtonian fluid was investigated numerically by direct-forcing immersed boundary (DFIB) method. The Navier–Stokes equations are coupled with equations of motion through virtual force to describe the motion of solid objects. Here, we rigorously derived the equations of motion by taking control-volume integration of momentum equation. The method was validated by a popular numerical test example describing the 2D flow caused by the free fall of a circular disk inside a tank of fluid, as well as 3D experimental measurements in the sedimentation of a sphere. Then, we demonstrated the method by a few more 2D sedimentation examples: (1) free fall of two tandem circular disks showing drafting, kissing and tumbling phenomena; (2) sedimentation of multiple circular disks; (3) free fall of a regular triangle, in which the rotation of solid object is significant; (4) free fall of a dropping ellipse to mimic the falling of a leaf. In the last example, we found rich falling patterns exhibiting fluttering, tumbling, and chaotic falling.

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Di Angelo, Luca Di, Francesco Duronio, Angelo De De Vita et Andrea Di Di Mascio. « Cartesian Mesh Generation with Local Refinement for Immersed Boundary Approaches ». Journal of Marine Science and Engineering 9, n^o 6 (25 mai 2021) : 572. http://dx.doi.org/10.3390/jmse9060572.

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In this paper, an efficient and robust Cartesian Mesh Generation with Local Refinement for an Immersed Boundary Approach is proposed, whose key feature is the capability of high Reynolds number simulations by the use of wall function models, bypassing the need for accurate boundary layer discretization. Starting from the discrete manifold model of the object to be analyzed, the proposed model generates Cartesian adaptive grids for a CFD simulation, with minimal user interactions; the most innovative aspect of this approach is that the automatic generation is based on the segmentation of the surfaces enveloping the object to be analyzed. The aim of this paper is to show that this automatic workflow is robust and enables to get quantitative results on geometrically complex configurations such as marine vehicles. To this purpose, the proposed methodology has been applied to the simulation of the flow past a BB2 submarine, discretized by non-uniform grid density. The obtained results are comparable with those obtained by classical body-fitted approaches but with a significant reduction of the time required for the mesh generation.

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15

Wu, Y. L., C. Shu et H. Ding. « Simulation of Incompressible Viscous Flows by Local DFD-Immersed Boundary Method ». Advances in Applied Mathematics and Mechanics 4, n^o 03 (juin 2012) : 311–24. http://dx.doi.org/10.4208/aamm.10-m1171.

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AbstractA local domain-free discretization-immersed boundary method (DFD-IBM) is presented in this paper to solve incompressible Navier-Stokes equations in the primitive variable form. Like the conventional immersed boundary method (IBM), the local DFD-IBM solves the governing equations in the whole domain including exterior and interior of the immersed object. The effect of immersed boundary to the surrounding fluids is through the evaluation of velocity at interior and exterior dependent points. To be specific, the velocity at interior dependent points is computed by approximate forms of solution and the velocity at exterior dependent points is set to the wall velocity. As compared to the conventional IBM, the present approach accurately implements the non-slip boundary condition. As a result, there is no flow penetration, which is often appeared in the conventional IBM results. The present approach is validated by its application to simulate incompressible viscous flows around a circular cylinder. The obtained numerical results agree very well with the data in the literature.

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Boskovic-Vragolovic, Nevenka, Danica Brzic et Zeljko Grbavcic. « Mass transfer between a fluid and an immersed object in liquid-solid packed and fluidized beds ». Journal of the Serbian Chemical Society 70, n^o 11 (2005) : 1373–79. http://dx.doi.org/10.2298/jsc0511373b.

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The mass transfer coefficient between fluid and an immersed sphere in liquid packed and fluidized beds of inert spherical particles have been studied experimentally using a column 40 mm in diameter. The mass transfer data were obtained by studying the transfer of benzoic acid from the immersed sphere to flowing water using the dissolution method. In all runs, the mass transfer rates were determined in the presence of inert glass particles 0.50-2.98 mm in diameter. The influence of different parameters, such as: liquid velocity, particles size and bed void age, on the mass transfer in packed and fluidized beds is presented. The obtained experimental data for mass transfer in the packed and particulate fluidized bed were correlated by a single correlation, thus confirming the similarity between the two systems.

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Ghasemi, Amirmahdi, R. Nikbakhti, Amirreza Ghasemi, Faraz Hedayati et Amir Malvandi. « Parallelized numerical modeling of the interaction of a solid object with immiscible incompressible two-phase fluid flow ». Engineering Computations 34, n^o 3 (2 mai 2017) : 709–24. http://dx.doi.org/10.1108/ec-01-2016-0016.

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Purpose A numerical method is developed to capture the interaction of solid object with two-phase flow with high density ratios. The current computational tool would be the first step of accurate modeling of wave energy converters in which the immense energy of the ocean can be extracted at low cost. Design/methodology/approach The full two-dimensional Navier–Stokes equations are discretized on a regular structured grid, and the two-step projection method along with multi-processing (OpenMP) is used to efficiently solve the flow equations. The level set and the immersed boundary methods are used to capture the free surface of a fluid and a solid object, respectively. The full two-dimensional Navier–Stokes equations are solved on a regular structured grid to resolve the flow field. Level set and immersed boundary methods are used to capture the free surface of liquid and solid object, respectively. A proper contact angle between the solid object and the fluid is used to enhance the accuracy of the advection of the mass and momentum of the fluids in three-phase cells. Findings The computational tool is verified based on numerical and experimental data with two scenarios: a cylinder falling into a rectangular domain due to gravity and a dam breaking in the presence of a fixed obstacle. In the former validation simulation, the accuracy of the immersed boundary method is verified. However, the accuracy of the level set method while the computational tool can model the high-density ratio is confirmed in the dam-breaking simulation. The results obtained from the current method are in good agreement with experimental data and other numerical studies. Practical/implications The computational tool is capable of being parallelized to reduce the computational cost; therefore, an OpenMP is used to solve the flow equations. Its application is seen in the following: wind energy conversion, interaction of solid object such as wind turbine with water waves, etc. Originality/value A high efficient CFD approach method is introduced to capture the interaction of solid object with a two-phase flow where they have high-density ratio. The current method has the ability to efficiently be parallelized.

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Ahmedov, Bobomurat, Bobur Turimov, Zdeněk Stuchlík et Arman Tursunov. « Optical properties of magnetized black hole in plasma ». International Journal of Modern Physics : Conference Series 49 (janvier 2019) : 1960018. http://dx.doi.org/10.1142/s2010194519600188.

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We study in the weak field limit the gravitational lensing by spherically symmetric compact object immersed in an asymptotically uniform magnetic field in the presence of plasma and our approach is based on the medium modified Hamiltonian one. We show that the magnetized plasma in the environment of compact object may lead to split of the Einstein cross, creating additional lensed components. Finally we calculate magnification and time delay related to the individual images.

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Duan, Xian Bao, Xin Qiang Qin et Ya Qin Guo. « Shape Optimization of a Body Immersed in the Navier-Stokes Flow ». Applied Mechanics and Materials 80-81 (juillet 2011) : 774–78. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.774.

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In this study, we restrict our attention to shape optimization of a body immersed in the Navier-Stokes fluid flow. The formulation and numerical results of the proposed method are presented. The proposed method is based on an optimal control theory. The optimal state is defined by the reduction of drag forces subjected to the immersed object. The cost functional should be minimized is governed by the Navier-Stokes equations. The shape sensitivity analysis of the cost functional was derived based on the adjoint method. Finally, a numerical example is given to show the feasible for the proposed algorithm.

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Kallel, Imen. « Topological Sensitivity Analysis for the Anisotropic Laplace Problem ». International Journal of Analysis and Applications 19, n^o 6 (16 novembre 2021) : 949–69. http://dx.doi.org/10.28924/2291-8639-19-2021-949.

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This paper is concerned with the reconstruction of objects immersed in anisotropic media from boundary measurements. The aim of this paper is to propose an alternative approach based on the Kohn-Vogelius formulation and the topological sensitivity analysis method. The idea is to formulate the reconstruction problem as a topology optimization one minimizing an energy-like function. We derive a topological asymptotic expansion for the anisotropic Laplace operator. The unknown object is reconstructed using level-set curve of the topological gradient. We make finally some numerical examples proving the efficiency and accuracy of the proposed algorithm.

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Nakatani, Masahiro, et Toshio Tagawa. « Computation of heat transfer around arbitrary object shape using an immersed boundary method ». Proceedings of the Thermal Engineering Conference 2018 (2018) : 0067. http://dx.doi.org/10.1299/jsmeted.2018.0067.

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ICHIGE, Yuya, Wataru YAMAZAKI et Shun TAKAHASHI. « Numerical Flow Analysis around a Flapping Wing Object Using an Immersed Boundary Method ». Proceedings of Conference of Hokuriku-Shinetsu Branch 2019.56 (2019) : H042. http://dx.doi.org/10.1299/jsmehs.2019.56.h042.

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Tsai, Yuan-Shiang, et Der-Chang Lo. « A Ghost-Cell Immersed Boundary Method for Wave–Structure Interaction Using a Two-Phase Flow Model ». Water 12, n^o 12 (29 novembre 2020) : 3346. http://dx.doi.org/10.3390/w12123346.

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The air-water two-phase flow model is developed to study the transformation of monochromatic waves passing over the submerged structure. The level set method is employed to describe the motion of the interface while the effect of the immersed object on the fluid is resolved using the ghost-cell immersed boundary method. The computational domain integrated with the air-water and fluid-solid phases allows the use of uniform Cartesian grids. The model simulates the wave generation, wave decomposition over a submerged trapezoidal breakwater, and the formation of the vortices as well as the drag and lift forces caused by the surface waves over three different configurations of the submerged structures. The numerical results show the capability of the present model to accurately track the deformation of the free surface. In addition, the variation of the drag and lift forces depend on the wavelength and wave induced vortices around the submerged object. Hence, the study observes that the triangular structure experiences the relatively small wave force.

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Lashina, Elena. « FACTOR OF THE REAL ENVIRONMENT OF THE OBJECT IN THE USE OF TERMS IN THE ARTISTIC TEXT ». Chronos : social sciences 6, n^o 1(21) (3 mars 2021) : 24–27. http://dx.doi.org/10.52013/2712-9705-21-1-5.

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The article is devoted to the identifying of the influence of the object factor to the using of terminological inclusions in the literary text. As a result of the study, the factor of the real environment of the object was identified. It underlies in the creation of code intertextuality. The terms show the connection between the object and the environment in which it is immersed, which indicates the general tendency to include terms in the text as obviously «ready-made things». The interpretative part of the text is usually missing. The conceptual part of the term is restored in the reader’s cognitive space.

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TEO, L. P. « MODE SUMMATION APPROACH TO CASIMIR EFFECT BETWEEN TWO OBJECTS ». International Journal of Modern Physics A 27, n^o 25 (10 octobre 2012) : 1230021. http://dx.doi.org/10.1142/s0217751x12300219.

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In the last few years, several approaches have been developed to compute the exact Casimir interaction energy between two nonplanar objects, all lead to the same functional form, which is called the TGTG formula. In this paper, we explore the TGTG formula from the perspective of mode summation approach. Both scalar fields and electromagnetic fields are considered. In this approach, one has to first solve the equation of motion to find a wave basis for each object. The two T's in the TGTG formula are [Formula: see text]-matrices representing the Lippmann–Schwinger T-operators, one for each of the objects. Each [Formula: see text]-matrix can be found by matching the boundary conditions imposed on the object, and it is independent of the other object. However, it depends on whether the object is interacting with an object outside it, or an object inside it. The two G's in the TGTG formula are the translation matrices, relating the wave basis of an object to the wave basis of the other object. These translation matrices only depend on the wave basis chosen for each object, and they are independent of the boundary conditions on the objects. After discussing the general theory, we apply the prescription to derive the explicit formulas for the Casimir energies for the sphere–sphere, sphere–plane, cylinder–cylinder and cylinder–plane interactions. First the [Formula: see text]-matrices for a plane, a sphere and a cylinder are derived for the following cases: the object is imposed with Dirichlet, Neumann or general Robin boundary conditions; the object is semitransparent; and the object is a magnetodielectric object immersed in a magnetodielectric media. Then the operator approach developed by R. C. Wittman [IEEE Trans. Antennas Propag.36, 1078 (1988)] is used to derive the translation matrices. From these, the explicit TGTG formula for each of the scenarios can be written down. On the one hand, we have summarized all the TGTG formulas that have been derived so far for the sphere–sphere, cylinder–cylinder, sphere–plane and cylinder–plane configurations. On the other hand, we provide the TGTG formulas for some scenarios that have not been considered before.

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Pushpakath, Madan, et Marcelo H. Ang Jr. « Design of a Liquid Jamming Gripper ». Designs 7, n^o 2 (10 mars 2023) : 44. http://dx.doi.org/10.3390/designs7020044.

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We present the design of a universal gripper based on the principle of liquid jamming. The phase change behavior of a mineral oil subjected to cooling is used for adaptive gripping and release of objects. The mineral oil is enclosed in a soft, compliant membrane molded into a spherical shape. The membrane with the liquid easily adapts to the shape of the object to be picked up. A thermoelectric cooling system is designed with a conductive spreader immersed in the oil to quickly cool the liquid held in a membrane. Once the membrane gripper conforms to the shape of the object partially enclosing it, the liquid is cooled below the phase change temperature, thus freezing the liquid and hardening the gripper around the object and effectively gripping it. We describe the design methodology of the gripper, part selection, and mechanical design. A proprietary controller developed by Venture Corporation is used for controlling the TEC module and the controller is based on a simple PID optimized using Ziegler–Nichols tuning for the P, I, and D values. The hardware is evaluated and the basic gripping functions on different odd-shaped objects are demonstrated. An invention disclosure has been submitted to the NUS IP office (ILO).

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Yue, Xiabing, Yuan Xie et Yongli Xie. « The Deformation Characteristics of Weak Foundation with High Back Siltation in the Immersed Tunnel ». Advances in Materials Science and Engineering 2018 (11 novembre 2018) : 1–14. http://dx.doi.org/10.1155/2018/6538764.

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The deformation characteristics of a weak foundation with high back siltation in an immersed tunnel lack empirical data; however, the calculation method and control of foundation settlements are highly important to tunnel design and construction. This paper takes a cross section of the natural foundation of an immersed tunnel in the Hong Kong-Zhuhai-Macao Bridge (HZMB) as the research object and conducts a centrifuge model test. The soil layer is divided, and the soil parameters are determined by the CPTU and the indoor dynamic three triaxial test. In consideration of the actual engineering scale and the ability of the centrifuge model test system, the similarity ratio of the model to the prototype is studied and determined. As for the immersed tube structure, the deformation characteristics are mainly studied. Therefore, the organic glass is selected as the model material by the similarity of the elastic modulus and the density. The characteristics of the resilience and recompression of the natural foundation of the immersed tunnel and the strain characteristics of the immersed tube structure are obtained by the analysis of the multiworking condition test data. Moreover, based on the actual engineering geological conditions of the subsea tunnel, a numerical calculation method is carried out to check the reliability of the centrifuge model test results. The results of the numerical calculation are consistent with the model test results.

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Gu, LingYun, FaTing Yuan, NaiYue Zhang, XueFeng Bai, Xin Zhang, WenPeng Gao, Yan Wu et ZhiXin Bai. « Research on temperature rise characteristics and hot spot temperature inversion method of oil-immersed transformer based on coupling of magnetic-fluid-thermal field ». Thermal Science, n^o 00 (2024) : 172. http://dx.doi.org/10.2298/tsci240330172g.

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The hot spot temperature is an important factor affecting the operation state and insulation life of oil-immersed transformer. It is of great value to carry out multi-physical field coupling simulation research on magnetic-fluid-thermal field of oil-immersed transformer and accurately calculate and predict the hot spot temperature of transformer for transformer service life evaluation. In this paper, the oil immersed transformer is taken as the research object, and five characteristic parameters of the hysteresis model are obtained by using PSO optimization algorithm according to the experimental magnetic characteristics data of the core material and the classical J-A hysteresis model, A 3D simulation model of magnetic-fluid-thermal field is established based on the electrical and structural parameters of the oil-immersed transformer. Combined with the magnetic characteristics of the core material, the thermal field and the surrounding fluid distribution of the transformer core and winding are obtained by two-way coupling method. On this basis, in order to accurately reflect the correlation between the hot spot temperature of the transformer winding and the temperature of the oil tank wall, the selection position of the characteristic temperature point of the transformer tank wall is determined by streamline analysis method, and the hot spot temperature of the oil-immersed transformer is retrieved by support vector machine method. The results show that the prediction accuracy of the hot spot temperature reaches 0.998, and the inversion method has a high enough accuracy. It provides theoretical basis and technical support for real-time monitoring of hot spot temperature in oil-immersed transformer windings.

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Stevens, Brett, Jennifer Jerrams-Smith, David Heathcote et David Callear. « Putting the Virtual into Reality : Assessing Object-Presence with Projection-Augmented Models ». Presence : Teleoperators and Virtual Environments 11, n^o 1 (février 2002) : 79–92. http://dx.doi.org/10.1162/105474602317343677.

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A projection-augmented model is a type of nonimmersive, coincident haptic and visual display that uses a physical model as a three-dimensional screen for projected visual information. Supporting all physiological depth cues and two sensory modalities should create a strong sense of the object's existence. However, conventional measures of presence have been defined only for displays that surround and isolate a user from the real world. The idea of object-presence is thus suggested to measure “the subjective experience that a particular object exists in a user's environment, even when that object does not” (Stevens & Jerrams-Smith, 2000). A correlation study was conducted to demonstrate the reliability and validity of objectpresence as a construct. The results of a modified Singer and Witmer Presence Questionnaire suggest the existence of a reliable construct that exhibits face validity. However, the Presence Questionnaire did not correlate significantly with a user's tendency to become immersed in traditional media, which would support the assertion that this construct was object-presence. Considering previous work, the results of the current correlation study exhibited a pattern evident in previous studies of presence suggesting that object-presence and presence could be gender biased by the task to be completed or by the presence measure.

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Chen, Wen Wu, Yan Rong Xu et Zhi Qian Guo. « Influence of Chloride Contamination on the Specific Surface Area of Loess ». Advanced Materials Research 838-841 (novembre 2013) : 894–900. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.894.

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The main chlorides that pollute soil are NaCl, KCl, MgCl2and CaCl2, who will change the physicochemical properties of soil. It takes Jiuzhoutai loess as the object, using methylene blue method and ethylene glycol monoethyl ether method to determinate the specific surface area of loess, which was immersed by chloride with different concentrations and cations to analyze the influence of chloride contamination, respectively. The specific surface area decrease with the increase of chloride concentration, while has the negative correlation with the affinity of cations to clay which immersed by different cations. Different absorbents that have lead to the difference of test results, and the results of ethylene glycol monoethyl ether method are always bigger than methylene blue method.

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Bušík, Martin, Martin Slavík et Ivan Cimrák. « Dissipative Coupling of Fluid and Immersed Objects for Modelling of Cells in Flow ». Computational and Mathematical Methods in Medicine 2018 (27 septembre 2018) : 1–11. http://dx.doi.org/10.1155/2018/7842857.

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Modelling of cell flow for biomedical applications relies in many cases on the correct description of fluid-structure interaction between the cell membrane and the surrounding fluid. We analyse the coupling of the lattice-Boltzmann method for the fluid and the spring network model for the cells. We investigate the bare friction parameter of fluid-structure interaction that is mediated via dissipative coupling. Such coupling mimics the no-slip boundary condition at the interface between the fluid and object. It is an alternative method to the immersed boundary method. Here, the fluid-structure coupling is provided by forces penalising local differences between velocities of the object’s boundaries and the surrounding fluid. The method includes a phenomenological friction coefficient that determines the strength of the coupling. This work aims at determination of proper values of such friction coefficient. We derive an explicit formula for computation of this coefficient depending on the mesh density assuming a reference friction is known. We validate this formula on spherical and ellipsoidal objects. We also provide sensitivity analysis of the formula on all parameters entering the model. We conclude that such formula may be used also for objects with irregular shapes provided that the triangular mesh covering the object’s surface is in some sense uniform. Our findings are justified by two computational experiments where we simulate motion of a red blood cell in a capillary and in a shear flow. Both experiments confirm our results presented in this work.

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ALLEN, J. E. « On the drag on an object immersed in a flowing plasma : the control surface approach ». Journal of Plasma Physics 73, n^o 5 (octobre 2007) : 773–83. http://dx.doi.org/10.1017/s0022377806006246.

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AbstractA theory of the drag force acting on an object immersed in a flowing plasma is presented. A control surface method is developed following the approach used in fluid mechanics rather than the linear dielectric response approach found in the literature. The situation examined is one in which the directed velocity of the ions dominates their thermal velocities; a cold ion model is employed.

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Qiu, Ju. « Fast Acoustic Imaging for a 3D Penetrable Object Immersed in a Shallow Water Waveguide ». Journal of Computational Mathematics 31, n^o 5 (juin 2013) : 449–69. http://dx.doi.org/10.4208/jcm.1304-m3983.

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Shen, Linwei, Eng-Soon Chan et Pengzhi Lin. « Calculation of hydrodynamic forces acting on a submerged moving object using immersed boundary method ». Computers & ; Fluids 38, n^o 3 (mars 2009) : 691–702. http://dx.doi.org/10.1016/j.compfluid.2008.07.002.

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Chang, Li, et Ali S. Rangwala. « Burning of fuel layers on a turbulent water surface with an immersed conductive object ». Combustion and Flame 252 (juin 2023) : 112745. http://dx.doi.org/10.1016/j.combustflame.2023.112745.

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Korneev, N. V. « Intensified cleaning of parts immersed in a detergent solution ». Agricultural Engineering, n^o 5 (2024) : 47–52. http://dx.doi.org/10.26897/2687-1149-2024-5-47-52.

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The quality of cleaning metal parts from contaminants depends on the physical and chemical properties of the washing medium and the intensity of the mechanical impact of the liquid on the surfaces subject to cleaning. Intensified cleaning of the parts is possible when there is an unsteady mode of a washing liquid flow, characterized by change of pressure and speed of a liquid in time and in each considered point of a surface subject to cleaning. In order to confirm the theoretical statement about the dependence of cleaning efficiency on the speed of the washing liquid flow, the authors made an experiment. They took a combined submerged washing machine using a combination of two hydromechanical methods of cleaning intensification. The parts subject to cleaning moved in the bath by means of the platform vibration. A helical blower provided the turbulent flow of the washing liquid relative to the object subject to cleaning. The authors used connecting rods of internal combustion engines as the objects to be cleaned. Their surfaces contained asphalt-resin contaminants, which were hard to remove. The cleaning process was studied in the aqueous solution of detergent Temp-100D with a concentration of 20 g/l at a temperature of 65 to 70°C. The cleaning lasted for 15 min. The quality of cleaning from contaminants was controlled by wettability of the cleaned surface with water. It was found that the intensity of cleaning, characterized by the liquid flow rate necessary for the detachment of dirt particles, depends on the vibration frequency of the platform holding the cleaned parts. Increasing the vibration frequency from 0.25 to 1.0 Hz leads to a three-fold increase in the flow rate of the cleaning solution, which provides an intensive removal of contaminants while increasing the quality of cleaning. When increasing the vibration frequency from 0 to 1.0 Hz, the cleaning efficiency increases in 2.5 times. The study results confirmed the theoretical supposition of the relationship between the cleaning efficiency and the washing liquid flow rate.

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Beliak, Gavriil Nikolaevich, et Mariia Naumovna Virolainen. « A WORK OF LITERATURE AS A HYPER-OBJECT (FROM AN ACADEMIC TO A DIGITAL PUBLICATION) ». Russkaya Literatura 4 (2024) : 226–30. https://doi.org/10.31860/0131-6095-2024-4-226-230.

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The article examines the existential reinterpretation of a literary work, once it is posted on the «Pushkin <digital>» portal, the successor of the academic edition of Pushkin’s legacy, that is dramatically different from the book format in its content and composition. The concept of a literary work as a hyper-object immersed in a system of links that are constantly updated and visualized in the interface is proposed.

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Lu, C., J. Lin, W. Chew et G. Otto. « Image Reconstruction with Acoustic Measurement Using Distorted Born Iteration Method ». Ultrasonic Imaging 18, n^o 2 (avril 1996) : 140–56. http://dx.doi.org/10.1177/016173469601800204.

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The distorted Born iterative method (DBIM) is applied to solve electromagnetics and ultrasonics inverse scattering problems. First, we use the DBIM to process the data, which are the scattered fields from two-dimensional cylinders with arbitrary cross section. From this simulation, we confirmed that the first-order Born approximation can be applied to larger objects as long as the phase change of a wave passing through the object due to its presence is smaller than a limit. Then we applied DBIM to process the ultrasonic measurement data. Images for a balloon and an egg that are immersed in water have been reconstructed and compared with those from the first-order diffraction tomography (DT).

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Yonezawa, Asahi, et Akira Yamada. « Deterioration of the Mechanical Properties of FFF 3D-Printed PLA Structures ». Inventions 6, n^o 1 (22 décembre 2020) : 1. http://dx.doi.org/10.3390/inventions6010001.

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Poly(lactic acid) (PLA) is a biodegradable polymer material used for the fabrication of objects by fused filament fabrication (FFF) 3D printing. FFF 3D printing technology has been quickly spreading over the past few years. An FFF-3D-printed object is formed from melted polymer extruded from a nozzle layer-by-layer. The mechanical properties of the object, and the changes in those properties as the object degrades, differ from the properties and changes observed in bulk objects. In this study we evaluated FFF-3D-printed objects by uniaxial tensile tests and four-point flexural tests to characterize the changes of three mechanical properties, namely, the maximum stress, elastic modulus, and breaking energy. Eight types of test pieces printed directly by an FFF 3D printer using two scan patterns and two interior fill percentages (IFPs) were tested by the aforesaid methods. The test pieces were immersed in saline and kept in an incubator at 37 °C for 30, 60, or 90 days before the mechanical testing. The changes in the mechanical properties differed largely between the test piece types. In some of the test pieces, transient increases in strength were observed before the immersion degraded the strength. Several of the test piece types were found to have superior specific strength in the tests. The results obtained in this research will be helpful for the design of PLA structures fabricated by FFF 3D printing.

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Puig Montella, Eduard, Cyrille Bonamy, Julien Chauchat et Tian-Jian Hsu. « Implementing moving object capability in a two-phase Eulerian model for sediment transport applications ». OpenFOAM® Journal 4 (22 avril 2024) : 79–104. http://dx.doi.org/10.51560/ofj.v4.119.

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This article presents the validation of a modified 6DoF solver which includes the contribution of particle forces on rigid objects. The solver is an extension of sedFoam, employed for a wide range of sediment transport applications. The first validation consists in a simple case of a sphere freely falling in a pure fluid. Then, the same sphere is submerged in a fluid with suspended particles. The next step involves placing a granular bed under the sphere to study its arrest due to particle-particle interactions. Lastly, the trajectory of a cylinder immersed in a uniform granular flow is studied to emphasize the lift and drag forces exerted by the particle phase on the solid object. Results show that overSedDyMFoam accurately reproduces experimental/numerical measurements successfully capturing the behavior of solid objects subjected to granular and fluid forces. This implementation is a significant step towards understanding complex interactions between fluid, particles, and structures.

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Diyana, Tsania Nur, Sutopo Sutopo et Dwi Haryoto. « THE STUDY OF STUDENTS’ DIFFICULTIES IN MASTERING THE CONCEPT OF ARCHIMEDES’ PRINCIPLE ». JURNAL PENDIDIKAN SAINS (JPS) 8, n^o 1 (20 avril 2020) : 59. http://dx.doi.org/10.26714/jps.8.1.2020.59-64.

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The focus of this study is to determine students' difficulties related to mastering the concept of Archimedes Principles topics. The study used descriptive quantitative method with the subject 35 XIth students. The research instrument was 10 multiple choice questions about Archimedes principle. Although there are improvements, but overall students do not fully understand the concept of the Archimedes principle. Difficulties among students are failing to understand that the buoyancy force is the resultant force by fluid pressure on the object and still considers the immersed object to have the Archimedes force affected by the depth of the object. When working on the application of the problem the students managed to answer correctly, but when completing the formulation questions the students were still get difficulties

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Winter, Bodo, et Benjamin Bergen. « Language comprehenders represent object distance both visually and auditorily ». Language and Cognition 4, n^o 1 (mars 2012) : 1–16. http://dx.doi.org/10.1515/langcog-2012-0001.

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AbstractWhen they process sentences, language comprehenders activate perceptual and motor representations of described scenes. On the “immersed experiencer” account, comprehenders engage motor and perceptual systems to create experiences that someone participating in the described scene would have. We tested two predictions of this view. First, the distance of mentioned objects from the protagonist of a described scene should produce perceptual correlates in mental simulations. And second, mental simulation of perceptual features should be multimodal, like actual perception of such features. In Experiment 1, we found that language about objects at different distances modulated the size of visually simulated objects. In Experiment 2, we found a similar effect for volume in the auditory modality. These experiments lend support to the view that language-driven mental simulation encodes experiencer-specific spatial details. The fact that we obtained similar simulation effects for two different modalities—audition and vision—confirms the multimodal nature of mental simulations during language understanding.

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Turimov, Bobur, Bobomurat Ahmedov, Ahmadjon Abdujabbarov et Cosimo Bambi. « Gravitational lensing by a magnetized compact object in the presence of plasma ». International Journal of Modern Physics D 28, n^o 16 (24 octobre 2019) : 2040013. http://dx.doi.org/10.1142/s0218271820400131.

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In the weak field approximation, we study the gravitational lensing by spherical symmetric compact object immersed in magnetic field in the presence of magnetized plasma. The external magnetic field causes the split of the deflection angle of the photon, Einstein ring and Einstein cross as the counterpart of the Zeeman effect. In particular, the magnetic field affects the magnification of images, creating additional components. We also study the time delay of an electromagnetic signal due to the geometry and the gravitational field around the lensing source. We show that the time delay of the electromagnetic signal strongly depends on the plasma parameters, and it slightly decreases in the plasma in comparison with that in vacuum.

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Gao, W. M., L. X. Kong et P. D. Hodgson. « Computational simulation of gas flow and heat transfer near an immersed object in fluidized beds ». Advances in Engineering Software 38, n^o 11-12 (novembre 2007) : 826–34. http://dx.doi.org/10.1016/j.advengsoft.2006.08.046.

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Liao, Chuan-Chieh, et Chao-An Lin. « Simulations of natural and forced convection flows with moving embedded object using immersed boundary method ». Computer Methods in Applied Mechanics and Engineering 213-216 (mars 2012) : 58–70. http://dx.doi.org/10.1016/j.cma.2011.11.009.

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Chakrabarti, Surajit, Sanjoy Kumar Pal et Soumen Sarkar. « An accurate determination of the refractive indices of water and glass by smartphone photography ». Physics Education 58, n^o 3 (22 février 2023) : 035010. http://dx.doi.org/10.1088/1361-6552/acb8f9.

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Abstract A smartphone can be used for many physics experiments by using the sensors built into the phone. The complementary metal oxide semiconductor (CMOS) (charge-coupled device, CCD) sensor of the camera records the images of objects photographed in pixels. The width of the image can be read off with micron level accuracy with the help of software available freely from the internet. If the dimensions of the object in the direction transverse to the viewing direction of the camera are known, the magnification of the object photographed can be determined accurately. A smartphone camera is a compound lens comprising a number of very thin lenses. A single thin lens is equivalent, as far as the transverse magnification is concerned, to a compound lens of the smartphone, when the thin lens has the same focal length as the effective focal length of the compound lens and is placed at its first principal plane. This property allows us to find experimentally the effective focal length of the compound lens of the camera accurately, using the thin lens equation. Once the focal length of the camera is known, the distance of an object can be determined by finding its magnification from the photograph. We have determined the refractive index of water accurately by photographing the apparent position of an object immersed in it. By determining the magnifications, we have found the real and apparent depths of the object. The ratio of these depths gives the refractive index. We have determined the refractive index of glass also using some thin glass slides.

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Abdujabbarov, Ahmadjon, Javlon Rayimbaev, Farruh Atamurotov et Bobomurat Ahmedov. « Magnetized Particle Motion in γ-Spacetime in a Magnetic Field ». Galaxies 8, n^o 4 (29 octobre 2020) : 76. http://dx.doi.org/10.3390/galaxies8040076.

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In the present work we explored the dynamics of magnetized particles around the compact object in γ-spacetime in the presence of an external asymptotically-uniform magnetic field. The analysis of the circular orbits of magnetized particles around the compact object in the spacetime of a γ-object immersed in the external magnetic field has shown that the area of stable circular orbits of magnetized particles increases with the increase of γ-parameter. We have also investigated the acceleration of the magnetized particles near the γ-object and shown that the center-of-mass energy of colliding magnetized particles increases with the increase of γ-parameter. Finally, we have applied the obtained results to the astrophysical scenario and shown that the values of γ-parameter in the range of γ∈(0.5,1) can mimic the spin of Kerr black hole up to a≃0.85, while the magnetic interaction can mimic the γ-parameter at γ∈(0.8,1) and spin of a Kerr black hole up to a≃0.3.

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Iwata, Hiroo, et Yoko Yoshida. « Path Reproduction Tests Using a Torus Treadmill ». Presence : Teleoperators and Virtual Environments 8, n^o 6 (décembre 1999) : 587–97. http://dx.doi.org/10.1162/105474699566503.

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This paper describes experiments regarding navigation performance using a new locomotion interface for walking through virtual space. Although traveling on foot is the most intuitive style of locomotion, proprioceptive feedback from walking is not provided in most applications of virtual environments. We developed an infinite surface driven by actuators for enabling a sense of walking. Torus-shaped surfaces are selected to realize the locomotion interface. The device employs twelve sets of treadmills, connected side by side and driven in perpendicular directions. The virtual infinite surface is generated by the motion of the treadmills. A walker can go in any direction while his/her position is fixed in the real world. The device is called a Torus Treadmill. Navigation performance was measured by path-reproduction tests. Subjects were immersed in a virtual grass-covered plain on which a cone-shaped target object was placed. The subjects first traveled to the target object. After they reached it, the target object disappeared and the rehomed subjects were asked to return to the place where the target object was placed. We also set two target objects, and the subject traveled along a bent path. We compared two locomotion modes: walking on the Torus Treadmill and moving purely by joystick operation. The results of the bent-path experiment showed that the accuracy of the path reproduction in the Torus Treadmill mode is better than that of joystick mode.

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Fattoyev, F. J., P. S. Tadjimuratov et N. B. Juraeva. « On time evolution of force-free magnetospheres around a slowly rotating compact object ». «Узбекский физический журнал» 23, n^o 1 (30 janvier 2021) : 1–7. http://dx.doi.org/10.52304/.v23i1.215.

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This paper reformulates the stability structure of force-free magnetosphere of a rotating black hole discussed in paper [1]. We do some corrections in the main equations of relativistic magnetohydrodynamics written by this author. It is shown that in a regime of slow rotation, evolution equations (18)-(20) and Maxwell equations (B6), (B7), and (B13) of paper [1] were not written correctly. Although there is a large number of typos in the equations given by [1], our calculations show this does not violate the stability structure of force-free magnetosphere which in its turn means that the energy extraction mechanism via surrounding, stable forcefree magnetosphere of a rotating black hole immersed in magnetic field can exist.

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BADRA, MEHDI, FABIEN CAUBET et MARC DAMBRINE. « DETECTING AN OBSTACLE IMMERSED IN A FLUID BY SHAPE OPTIMIZATION METHODS ». Mathematical Models and Methods in Applied Sciences 21, n^o 10 (octobre 2011) : 2069–101. http://dx.doi.org/10.1142/s0218202511005660.

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The paper presents a theoretical study of an identification problem by shape optimization methods. The question is to detect an object immersed in a fluid. Here, the problem is modeled by the Stokes equations and treated as a nonlinear least-squares problem. We consider both the Dirichlet and Neumann boundary conditions. Firstly, we prove an identifiability result. Secondly, we prove the existence of the first-order shape derivatives of the state, we characterize them and deduce the gradient of the least-squares functional. Moreover, we study the stability of this setting. We prove the existence of the second-order shape derivatives and we give the expression of the shape Hessian. Finally, the compactness of the Riesz operator corresponding to this shape Hessian is shown and the ill-posedness of the identification problem follows. This explains the need of regularization to numerically solve this problem.

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