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This article belongs to the Special Issue Actuators and Dampers for Vibration Control: Damping and Isolation Applications. We present the design, manufacturing, and dynamical characterization of a mechanical suspension made by a passive magnetic spring and an eddy current damper integrated into a single device. Three configurations with 2, 3, and 4 permanent magnets axially distributed with opposite polarizations are designed, simulated, manufactured, and tested. Stiffness of 2410, 2050, 2090 N/m and damping coefficient of 5.45, 10.52 and 17.25 Ns/m are measured for the 2-, 3-, and 4-magnets configurations, respectively. The magnetic suspension provides good mechanical properties combined with excellent cleanness and high reliability, which is very desirable in mechanical systems for space applications. The research leading to these results has received funding from the Spanish Ministerio de Economía y Competitividad under the Plan Estatal de I+D+I 2013-2016, grant agreement no ESP2015-72458-EXP.

Due to their robustness, compactness, simplicity, and the possibility of nonlinear torque curves, spiral springs are being increasingly contemplated for industrial application. Recent manufacturing technologies and materials allow for the creation of spiral springs of various shapes and geometries able to provide the required torque curves. Modeling the behavior of this kind of springs is highly complex due to the strong nonlinearities arisen from large deflections and the possibility of coiling of strip length around the spring barrel or arbor. For this reason, up to our knowledge, existing models only provide design features such as deflection and torque curve for the simplest strip geometries, and fewer models supply, only if no strip coiling occurs, reactions at the strip-barrel and strip-arbor clampings. In addition, to our knowledge, just semi-empirical models for strip-barrel, -arbor and -strip contact forces or friction torques were available. In this work, we introduce a novel general, an analytical quasistatic model for the calculation of all the above spring characteristics for any length-dependent strip material and initial geometry and strip cross-sectional shape and for any barrel and arbor radii. The strip deflection curvatures are calculated minimizing the sum of elastic and gravitational potential energies under geometrical constraints associated with eventual strip coiling. Once the curvatures are calculated, the spring internal, contact, and reaction forces can be straightforwardly calculated by solving the elastica differential equations. Friction is taken into account by evaluating the contact conditions at the strip coiled sections.

The ITER equatorial visible and infrared Wide Angle Viewing System (WAVS) provides surface temperature measurements of plasma facing components by infrared (IR) thermography being one of its main roles to protect them from damage. It also images the plasma emission in the visible range. The diagnostic, which comprises 15 lines of sight distributed in four equatorial ports (3, 9, 12 and 17), will contribute to Machine protection, Basic control and Physics analysis in ITER. The design of the diagnostic in the equatorial port 12 (EP12) - comprising three lines of sight - is currently being developed within a Framework Partnership Agreement through a Specific Grant granted by F4E to the Consortium formed by CEA, Ciemat and Bertin Technologies. EP12 has to be operative for the ITER first plasma. The overview of the WAVS opto-mechanical design for the ex-vessel components in EP12 will be presented in the paper. The ex-vessel optics are composed of mirrors and refractive elements which relay the exit image of the port plug at the vacuum window up to the cameras placed inside a shielded cabinet in the Port Cell. The image relay through the Interspace, Bioshield and Port Cell has to cover a length of almost 10 m in order to reach the detectors. The refractive elements are arranged in sub-assemblies (optical modules) mechanically mounted in barrels and next assembled on a support structure. The assembly of these modules on site will be also presented in the paper. Furthermore, the Optical Hinge which is the first component of the ex-vessel optical chain (formed by two folding mirrors) aims to compensate the differential motion between the vacuum vessel and the building, in normal operation and baking. The mechanical assembly and the operation of this component will be also described in the paper.

The aim of this study is the detailed calculation of microwave propagation inside raw timber in cylindrical configurations. Two different approaches have been used. The first one uses an exact formulation and analytical approximations in order to explore the electromagnetic field distribution inside dry wood. The introduction of conductivity in the exact model makes it so complex that the equations are unsuitable for analytical manipulation. In order to further explore the effect of moisture in cylindrical wood structures, a full scale numerical simulation using commercial software has been performed. The results show that for microwave frequencies in the 3 GHz range and for typical wood parameters, a cylindrical log behaves as a kind of Fresnel lens. This work has important applications in microwave treatment and sensing of wood.

This paper describes an experimental procedure consisting of impact tests that simulate a collision of a human head with an industrial robot with the aim to validate a safety index named as New Index for Robots (NIR) and its outputs. The experiments in this paper are based on lab tests. It is an attempt to characterize the NIR index underlying the main parameters that are involved in crash interaction and to highlight limitations and weakness of suggested impact tests.