Thermal and damping behaviour of magnetic shape memory alloy composites

Single crystals of ferromagnetic shape memory alloys (MSMA) exhibit magnetic field and stress induced strains via energy dissipating twinning. Embedding single crystalline MSMA particles into a polymer matrix could thus produce composites with enhanced energy dissipation, suitable for damping applications. Composites of ferromagnetic, martensitic or austenitic Ni-Mn-Ga powders embedded in a standard epoxy matrix were produced by casting. The martensitic powder composites showed a crystal structure dependent damping behaviour that was more dissipative than that of austenitic powder or Cu-Ni reference powder composites and than that of the pure matrix. The loss ratio also increased with increasing strain amplitude and decreasing frequency, respectively. Furthermore, Ni-Mn-Ga powder composites exhibited an increased damping behaviour at the martensite/austenite transformation temperature of the Ni-Mn-Ga particles in addition to that at the glass transition temperature of the epoxy matrix, creating possible synergetic effects

Effect of annealing and silylation on the strength of melt-spun Ni-Mn-Ga fibres and their adhesion to epoxy

Single crystals of ferromagnetic Ni-Mn-Ga shape memory alloys show magnetic-field and stress induced twinning, leading to shape memory. Adaptive composites can thus be produced by embedding single crystalline particles or bamboo-structured Ni-Mn-Ga fibres into a polymer matrix. To guarantee a durable performance of these composites, adhesion between reinforcement phase and matrix should be quantified and optimised. The influence of annealing and surface treatment with an aminosilane of melt-spun Ni-Mn-Ga fibres on their strength and adhesion to an epoxy matrix was investigated using single fibre tension and fragmentation tests. Annealing of the melt-spun Ni-Mn-Ga fibres changed the surface from a "pimpled" to a smooth microstructure. This resulted in a reduced adhesion of the annealed fibres in comparison to the as-spun fibres embedded in an epoxy matrix. As-spun fibres exhibited an interfacial shear strength (IFSS) comparable to the shear strength of the epoxy matrix so that the silylation did not change the adhesion significantly. For the annealed fibres, the silane treatment improved the IFSS by 67%. Furthermore, the silylation increased the fracture strength of the Ni-Mn-Ga fibres due to surface flaw healing or forming of a protective surface coating. (C) 2014 Elsevier Ltd. All rights reserved

Magneto-mechanical actuation of ferromagnetic shape memory alloy/epoxy composites

Ferromagnetic shape memory alloys (MSMA) exhibit magnetic field- and stress-induced twinning when processed into single crystals, but are brittle and difficult to shape. Embedding slender single crystalline MSMA elements into a polymer matrix can thus provide composites with adjustable magnetic strain actuation behavior. Ni-Mn-Ga single crystalline rods were characterized for their magneto-mechanical behavior and embedded in two different types of epoxy matrices with different volumetric fractions. The magnetic actuation of the composites was measured and shown to depend on the Ni-Mn-Ga volumetric fraction and the matrix stiffness. This behavior was well predicted by finite element simulations of the composite using a simple material model for the strain of the MSMA as a function of the magnetic field and applied stresses. Guidelines for composite behavior prediction could thus be proposed. (C) 2015 Elsevier Ltd. All rights reserved

Cell-type-specific metabolic labeling of nascent proteomes in vivo

Although advances in protein labeling methods have made it possible to measure the proteome of mixed cell populations, it has not been possible to isolate cell-type-specific proteomes in vivo. This is because the existing methods for metabolic protein labeling in vivo access all cell types. We report the development of a transgenic mouse line where Cre-recombinase-induced expression of a mutant methionyl-tRNA synthetase (L274G) enables the cell-type-specific labeling of nascent proteins with a non-canonical amino-acid and click chemistry. Using immunoblotting, imaging and mass spectrometry, we use our transgenic mouse to label and analyze proteins in excitatory principal neurons and Purkinje neurons in vitro (brain slices) and in vivo. We discover more than 200 proteins that are differentially regulated in hippocampal excitatory neurons by exposing mice to an environment with enriched sensory cues. Our approach can be used to isolate, analyze and quantitate cell-type-specific proteomes and their dynamics in healthy and diseased tissues

Transforming city neighbourhoods in a child-friendly way to increase the quality of life for all citizens

City planning has historically been largely top down, with a focus on economic development and association withmotor car use, which has led to many problems in our cities. There is now growing appetite for change, with amove towards liveable neighbourhoods that also encourage active mobility, but the mechanisms for delivering thisfor the benefit of the wider population are still being investigated, and city planners and policy makers need furtherideas and inspirations in order to achieve these objectives. This paper therefore uses the findings from the EUHorizon 2020 Metamorphosis Project to show how a bottom-up approach that engage children, as well as widercommunities as a whole, can provide the inspirations for change, and improve the existing processes and schemesfor increasing active travel in the cities highlighted, as well as enhancing the liveability of its streets and sharedspaces for people, especially children