1,721,880 research outputs found
Effective negative swelling of hydrogel-solid composites
No full textEffective negative swelling is a phenomenon that refers to the reduction of a solid volume after absorption of a solvent. Here, I focus on hydrogel solids and propose an alternative technique to achieve effective negative swelling. Particularly, I show that using homogeneous and isotropic hydrogel unit cells joined by rigid connections with impermeable inner cavities is enough to achieve this phenomenon. The key feature of this method is to use specific unit cells and decompose the problem in two steps; the first concerns the final shape of a unit cell after absorption of the solvent; the second consists in creating an array with these unit cells using rigid connections realizing what it may be called a metahydrogel
Enforcing shaping of thin gel sheets by anisotropic swelling
Full text linkThis paper investigates swelling-induced shaping in bilayer thin plates. Sphere-like and nearly developable shapes are realized and the ability to control a specific shaping, shifting from one shape to another, under anisotropic swelling is investigated. It is shown that reinforcing fibers can be crucial in controlling shaping under swelling and dramatically affect the characteristics of the final shapes
Mechanics of active gel spheres under bulk contraction
No full textIn active gels, liquid redistribution, network deformation and material remodeling due to bulk activation, mimicking the presence of molecular motors, are strongly coupled. We present a consistent mathematical model capable to gain a deep understanding of the phenomenon in both steady and transient conditions. With explicit reference to active gel spheres, we evidence the role that not uniform bulk activation may have in generating local stress or strain actuators based on liquid redistribution
On the validity of plane state assumptions in the bending of bimorph piezoelectric cantilevers
No full textWe assess the accuracy of plane state assumptions in modeling the bending of bimorph piezoelectric cantilevers. Reference solutions are obtained by means of fully three-dimensional simulations. We solve a model, compliant with the standard theoretical background, able to deal with large deflections, and aimed at estimating the electrical energy harvesting potential. We show that the two assumptions of plane stress and plane strain yield very different results in terms of strain and therefore lead to substantially different estimates of electrical power. The plane stress state is the best approximation of narrow cantilevers, while the plane strain is suited for wide ones. The validity ranges are defined for each of the two, in terms of the generated electrical power. More specifically, the plane stress assumption better approximates the reference solution in the range W/H<10. By contrast, the plane strain condition yields results closer to three-dimensional solution for ratios W/H>103 with W the width and H the total thickness of the solid. Other aspects are affected by the modeling approach, such as the estimation of maximum deformation and, to a minor extent, of resonance frequencies
Enforcing shaping of thin gel sheets by anisotropic swelling
No full textThis paper investigates swelling-induced shaping in bilayer thin plates. Sphere-like and nearly developable shapes are realized and the ability to control a specific shaping, shifting from one shape to another, under anisotropic swelling is investigated. It is shown that reinforcing fibers can be crucial in controlling shaping under swelling and dramatically affect the characteristics of the final shapes
Enhancing flow induced vibrations of a thin piezoelectric cantilever: Experimental analysis
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
«Neurobiologie der Schmerzchronifizierung nach HWS-Distorsionstrauma (Neurobiology of pain after whiplash injury). In: Beschleunigungsverletzung der Halswirbelsäule (Whiplash injury)»
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