Delamination on GFRP laminates impacted at room and lower temperatures: Comparison between epoxy and vinylester resins

Low velocity impact tests at three different impact energy values and three different temperatures, were performed on glass fibre composite laminates made by infusion technology. Two different resins, epoxy and vinylester, were considered to impregnate the fibres: the first is mainly of aeronautical interest whereas the second one is mainly applied in Naval field. The specimens were first completely destroyed to obtain the complete load-displacement curve. The latter allowed the evaluation of the increasing impact energies, 5, 10 and 20J, used to investigate about the start and propagation of the damage inside the laminates. The delamination was investigated by the very commonly used Ultra Sound technique and the results obtained on the different materials at different temperatures were compared. A general better behaviour of vinylester resin was noted. © 2016 Author(s)

Ultrasonic inspection of composites materials: Application to detect impact damage

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Achievement and exploitation of porous geopolymer-based spheres

Several spherification processes were applied to obtain porous geopolymer spheres, different in term of porosity, specific surface area and adsorption properties. The processes are based on the formulation of metakaolin-based geopolymer slurries, produced using a potassium- or sodium-based alkaline activating solution, and exploiting an injection-solidification method in different mediums, i.e. polyethylene glycol (PEG), liquid nitrogen or calcium chloride, to produce the spheres. When liquid nitrogen was used, the geopolymer slurries underwent a maturation step (several hours at room temperature) to trigger the geopolymerization without reaching a complete chemical consolidation. Spheres were obtained injecting in liquid N2 the mixture as it is or mixed with water, to modulate the final porosity (ice-templating process). The spheres were then freeze dried to remove the solidified water and complete the chemical consolidation of the geopolymer. Please click Additional Files below to see the full abstract

Lightweight insulating geopolymer material based on expanded perlite

Expanded perlite, owing to its lightweight and excellent thermal insulating properties, has been extensively used in different industrial sectors to produce self-standing insulating boards bonded with various organic polymers or calcium-silicates. In order to improve the high temperature behavior and mechanical performances of such materials inorganic binders, such as geopolymers, can be regarded as a promising alternative. Please click Additional Files below to see the full abstract

Recombinant protein expression system in cold loving microorganisms

Soluble and functional proteins are of high demand in modern biotechnology. Although many recombinant proteins have been successfully obtained from common prokaryotic and eukaryotic hosts, these systems result to be often unproductive due to the peculiar properties of the protein to be produced. Incorrect folding of the nascent polypeptide chains is one of the main problems occurring during heterologous protein production in bacteria. Since formation of inclusion bodies often impairs the recombinant production of valuable proteins, many experimental approaches have been explored to minimize this undesirable effect [1, 2]. Expression of "difficult" proteins has also been carried out by lowering the temperature at the physiological limit allowed for the growth of mesophilic host organisms (between 15 and 18°C for Escherichia coli). Lowering the temperature, in fact, has a pleiotropic effect on the folding process, destabilising the hydrophobic interactions needed for intermediates aggregation [3]. On the basis of the above considerations, a rational alternative to mesophilic organisms is the use of naturally cold-adapted bacteria as hosts for protein production at low temperature (even at around 0°C)

The Influence of Temperature on the Low-Velocity Impact Response of Polyamide 6/Basalt Plain Fabric Laminates

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Geopolymer-zeolite composites for CO2 adsorption

Geopolymer-zeolite composites were produced mixing different geopolymer matrices with a synthetic commercial Na13X zeolite, to combine the functional microporosity of the zeolite with the mesoporosity of the geopolymer matrix, with the further possibility to consolidate the zeolite powder. The new materials were designed and produced in forms of monoliths to be used as adsorbents for low temperature CO2 capture applications. A potassium or sodium silicate activating solution was used to produce the metakaolin-based geopolymer matrices, then mixed with the synthetic zeolite used as a filler. As geopolymers can be regarded as the amorphous counterpart or precursor of crystalline zeolites, it is important to underline the chemical affinity between these two constituents. As a matter of fact, the morphological characterization evidenced the presence of geopolymer nanoprecipitates covering zeolite particles for the K-based composite, while in the Na-based composite the formation of a NaA zeolite phase was evidenced (Fig. 1). Please click Additional Files below to see the full abstract

Geopolymers adsorbents: Production and use

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Full-Thickness Skin Burn Caused by Radiofrequency Ablation of a Benign Thyroid Nodule

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