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By extending the analysis of the slow dynamics, the solutions of a double pendulum motion written as a linear superposition of Coulomb vibrations have broken symmetry concerning the driving excitation. The solutions allow a qualitative analysis not only of the quasi-periodic behavior but also of the chaotic behavior of the pendulum. The solutions permit understanding what causes an oscillation to lose its periodicity and hence become chaotic. [ABSTRACT FROM AUTHOR]

The paper is using the nonlocal field equations for modelling a nanocontact made from the thin films. The theory describes long-range interactions among the particles. An elastic layer loaded by a rigid indenter is considered. We show that the stress field is finite for all points and have a maximum value that does not occur at the boundary of the contact domain. [ABSTRACT FROM AUTHOR]

The paper presents a low-cost experimental setup consisting of a shaking table, a displacement measuring system based on non-contact optical infrared (IR) sensors, along with a standard acceleration measuring system, based on PZT accelerometers and signal conditioners. A 3 level reduced scale model of a lightweight frame structure, subjected at the base by transient seismic loads, is presented in this study. A methodology to obtain good agreement between measurements and 3D finite element method (FEM) computations of a structure subjected to transient loads is presented. It consists in 3 steps. In the first and by applying sinusoidal loads at the base of the structure, a frequency domain study was done. In second step, inducing free vibrations, a time-domain analysis was made. By using FEM as an inverse method to match experimental results, the elastic and damping properties of the structure materials were determined. In the third step, the validation step, transient loads measurements were carried out for both accelerations and displacements. As the excitations loads and the response of the structure are transient, a simple the integration of measured accelerations to obtain displacements is not possible. The measured displacements with low-cost noncontact optical IR sensors showed an acceptable accuracy in the small range of interest. The experimental measurements were compared with FEM computation results, showing good agreement. [ABSTRACT FROM AUTHOR]

The aim of the paper is to find a parametrical representation for the constitutive laws for which the motion equations can be associated to a pseudospherical surface with negative Gaussian curvature K. These constitutive laws suggest the existence of a Tzitzeica surface for which the ratio K/d4 constant, where d is the distance from the origin to the tangent plane at an arbitrary point. [ABSTRACT FROM AUTHOR]

The Ricci equation and the soliton solutions are obtained in this paper for two coupled pendula in order to optimise its locomotion and structure. The robot is swinging repeatedly like a rope with successive movement steps along a mobile support. The cnoidal theory and a genetic algorithm are used to solve the problem via the Ricci solitons and the pseudospherical reduction of the rheological Zener equations. The Bäcklund transform is applied to Ricci equation to generate pseudospherical surfaces. [ABSTRACT FROM AUTHOR]

The paper discusses the behavior of a Euler-Bernoulli beam with external patches made from GeSbTe chalcogenide material. The nonlocal theory is used to model the damping force as a weighted average of the velocity field over a suitable distance. The resonance is avoided through a careful choosing of the patch location and the eigenvalues. The atomic-level knowledge of the material gives the route for understanding their properties necessary to specific devices. [ABSTRACT FROM AUTHOR]

Chalcogenide thin films based on Ge-Sb-Te (GST) are synthesized from elements with 5N purity using the conventional melt-quenching method. The mixture was used as material for deposition on quartz substrate by the chemical vacuum deposition method. Optical and dielectric properties were determined by Spectro-ellipsometry measurements. The optical dispersion parameters are calculated using the single-oscillator model of Wemple--DiDomenico. The dissipation factor, the optical conductivity, the complex electric modulus, and the complex impedance of these GST layers were calculated. The AFM-SEM imagines revealed compact, continuous, and smooth films with good adhesion and uniform granules distribution. [ABSTRACT FROM AUTHOR]

We report the deformation of the needle during its insertion into the human liver in the context of surgery simulation of the high-robotic-assisted intraoperative treatment of liver tumors based on the integrated imaging-molecular diagnosis. The bee needle is modeled as a flexible thread within the framework of the nonlinear elasticity theory. The motion equations of the needle are similar to Tzitzeica equations of surfaces which are invariant under the group of centro-affine transformations. That means the surfaces tend to minimize their area and have a minimal Dirichlet energy of how variable a function is. The closed form solutions are obtained for deformation of the needle. In addition, the collision between the needle and the tissues is modeled as a minimization problem. [ABSTRACT FROM AUTHOR]

Transformation acoustics opens a new avenue towards the architecture, modeling and simulation of a new class of sonic composites with scatterers made of various materials and having various shapes embedded in an epoxy matrix. The design of acoustic scatterers is based on the property of Helmholtz equations to be invariant under a coordinate transformation, i.e., a specific spatial compression is equivalent to a new material in a new space. In this paper, the noise suppression for a wide full band-gap of frequencies is discussed for spherical shell scatterers made of auxetic materials (materials with negative Poisson's ratio). The original domain consists of spheres made from conventional foams with positive Poisson's ratio. The spatial compression is controlled by the coordinate transformation, and leads to an equivalent domain filled with an auxetic material. The coordinate transformation is strongly supported by the manufacturing of auxetics which is based on the pore size reduction through radial compression molds. [ABSTRACT FROM AUTHOR]

In the last decades, the optimum design has driven the scientists to find new solutions in robotics based on specific performance requirements such as the dexterity and manipulability indices, the Jacobian condition number and minimum singular value. The optimization problem is multi-objective to nature, due to the fact that the design process may require a large number of performance measures relating to the kinematic, kinetostatic and dynamic properties. The maximization of the workspace and the minimization of the mass are common design criteria. Kinematic demands are related to the stiffness matrix computation and are less complex that the dynamical ones in which the structure and its evaluation is very important. The performance indices are reviewed in this paper together to their variation in the workspace. [ABSTRACT FROM AUTHOR]

This paper is the second part of our previous one. We present here two examples which highlight the theory. The first example is a spatial one, the conservative forces being the weight and linear elastic forces. The second example is a planar one and it involves as conservative forces the weight, a linear elastic force and a non-linear elastic force. Different constraints are considered and the calculation of the corresponding matrices of constraints is detailed. We present the main steps in solving the problems and discuss different way in approaching of the solutions. [ABSTRACT FROM AUTHOR]

The chalcogenide ternary thin films should provide efficient solutions to develop the color filter-free image sensors for rapid capture of vivid colors detection of the motion images of a scene in the cognitive processes of perception and interpretation of motion. The image sensor consists of a light-sensitive cell having a lower and a higher electrode. The chalcogenide thin film is placed between the electrodes together with an imaging circuit that measures the wavelength and the intensity of the incident light beam. This paper proposes an easy-to-use, visual attention model that use the filter-less color image sensor to a mobile supervising robot able to detect not only the motion but also the intent and the purpose of the motion. The robot oversees the subjects' activities, the motion goals and intentions by exploring the eventually dangerous events that could appear during the motion. The feasibility of the proposed attention model has been demonstrated by simulating an example that tracks the dangerous situations on a volleyball game on a playground. [ABSTRACT FROM AUTHOR]

This paper discusses an algorithm for simulation, computation and control of the hybrid systems. The algorithm is known under the name the differential dynamic logic (dL). The hybrid systems are complex dynamical structures that couple the continuous motions with discrete motions of their constituents. Hybrid systems can be found in the biomedical industry, robotics, automotive, railway and aerial navigation. A system can flow or jump, can slip or collide with objects, or can be a cooperative surgeon-robot. A bouncing ball, for example, is an example of hybrid system that can exhibit continuous motions between each bounce and discrete motions between impacts to ground. This behavior describes a system with an infinite number of jumps in a finite interval of time. The dL incorporates the discrete and the continuous behavior of the system and can be used for computation and control of a hybrid system with uncertain boundary data modeled as a lognormal random field. This paper discusses the behavior of a cooperative surgeon-robot in which the coupling between the continuous motions of the surgeon and the discrete motions of the robot are incorporated in a single routine in which the computation, physical aspects and control are interacting. [ABSTRACT FROM AUTHOR]