Search results for "Composite"
showing 10 items of 4584 documents
Effect of Cu-Zn coated steel fibers on high temperature resistance of reactive powder concrete
2019
Abstract Even though many studies have reported about the impacts of shape, length and distribution of steel fiber reinforcement on global concrete properties, there is a lack of information about the influence of coating type of steel fibers on high temperature resistance of concrete. This paper describes the effect of Cu-Zn coated steel fibers on selected properties of reactive powder concrete (RPC) after exposure to elevated temperatures. The initial corrosion of zinc in Cu-Zn surface layer is found to be already activated by the alkaline environment of the fresh concrete. The RPC samples reinforced with Cu-Zn coated steel fibers are heated to 600 °C and 1000 °C, and the influence of the…
Debonding failure mechanisms in prestressed CFRP/epoxy/concrete connections
2014
Abstract This paper presents an investigation on the failure mode in prestress force-release tests of CFRP strips bonded to concrete substrates. Background of the study is the gradient anchorage technique. Firstly, experimental test series are presented. It is shown that considerable differences in failure mechanisms between lap-shear and the before mentioned release tests exist. The study reveals a strong Mode I-influence in the debonding process, compared to a Mode II for lap-shear tests. Secondly, FE simulations with a commercially available software are introduced. It is demonstrated that delamination in a force-release test occurs by a mixed-mode failure over the strip width.
The gut as reservoir of antibiotic resistance: microbial diversity of tetracycline resistance in mother and infant.
2011
The microbiota in the human gastrointestinal tract (GIT) is highly exposed to antibiotics, and may be an important reservoir of resistant strains and transferable resistance genes. Maternal GIT strains can be transmitted to the offspring, and resistances could be acquired from birth. This is a case study using a metagenomic approach to determine the diversity of microorganisms conferring tetracycline resistance (Tc(r)) in the guts of a healthy mother-infant pair one month after childbirth, and to investigate the potential for horizontal transfer and maternal transmission of Tc(r) genes. Fecal fosmid libraries were functionally screened for Tc(r), and further PCR-screened for specific Tc(r) …
Biphasic dimerisation of methylacrylate--immobilisation and stabilisation of cationic Pd-catalysts in ionic liquids by an ammoniumphosphine ligand.
2002
The first continuous, biphasic, Pd-catalysed dimerisation of methylacrylate is described. The biphasic system has been realised by using a tetrafluoroborate ionic liquid as catalyst medium and an ammoniumphosphine ligand to immobilise and stabilise the Pd-catalyst.
Synthesis and Characterization of Iron-Doped ZrSiO4 Solid Solutions from Gels
2011
The mechanism of formation and the structural features of tetragonal Fe–ZrO2-amorphous silica composites and particulated Fe-doped ZrSiO4 solid solutions were studied. A series of specimens with compositions Fex–ZrSiO4, 0 ≤ x ≤ 0.10 were prepared by sol–gel techniques and thermally annealed over the range of temperature between 400°C and 1600°C. Results confirmed the formation of tetragonal Fe–ZrO2 solid solution as first crystalline phase on the whole process leading to Fe-doped ZrSiO4 solid solution. The annealing temperature for the preparation of Fe-containing ZrSiO4 solid solutions was dependent on the nominal amount of iron. The Fex–ZrSiO4 solid solutions, with 0.02 < x < 0.08, were a…
A 2,3-dialkoxynaphthalene-based naphthocage
2019
A 2,3-dialkoxynaphthalene-based naphthocage has been synthesized. This naphthocage prefers to bind small organic cations with its low-symmetry conformation, which is in contrast to 2,6-dialkoxynaphthalene-based naphthocages. Self-sorting of these two naphthocages with two structurally similar guests tetramethylammonium and tetraethylammonium was achieved as well. peerReviewed
Novel method for functionalising and patterning textile composites:Liquid resin print
2016
Abstract The paper reports a novel method of integrating resin into continuous textile reinforcement. The method presents a print of liquid reactive resin into textile preforms. A series of targeted injections forms a patch which upon consolidation and curing transforms into a stiff region continuously spanning through preform thickness. Enhancing the injected resin with conductive phase allows creating a pattern of patches with controlled dimensions and added functionalities. Patterned composites reveal features which are not typical for conventional composites such as fibre bridged interfaces, regular thickness variation, and gradient matrix properties. The presented study explores the ro…
Experimental Studies Regarding Mechanical Behaviour of Textile Reinforcements Laminated Composite Materials
2013
The aim of this paper is to determine the mechanical properties of textile reinforcements laminated composite material and to establish the influence of thickness about these properties. The composite material used for this is a laminated sheet of HGW 2082. In order to study the mechanical behaviour of these kinds of materials we select two experimental tests: uniaxial test and bending test. For the uniaxial test we have measured the maximum load, the maximum extension, the maximum tensile stress and the maximum tensile strain. Also, using an optical extensometer we measured the major and the minor strains. For the bending test we measured the maximum load and the maximum bending deflection…
Strength prediction of a triaxially braided composite
2011
The architecture of textile reinforcement affects the deformation and failure behavior of the textile reinforced composites. This paper presents an approximate method that incorporates the in-plane periodic meso structure of the textile composite in finite element models. In this approach, the representative unit cell (RUC) of a textile composite is divided into sub-cells. Instead of obtaining a homogeneous equivalent, these sub-cells are idealized and represented with laminates of different layups using shell elements. In this way, an RUC can be constructed with a small number of elements. This method holds the promise of creating a textile composite FE model with an improved accuracy with…
Zinc oxide application in the textile industry: surface tailoring and water barrier attributes as parameters with direct implication in comfort perfo…
2013
The present study focuses on surface tailoring and water barrier attributes of zinc oxide (ZnO)-polyester composite textile materials. The surface properties, such as surface topography and roughness, composite compositions as well as thermal stability of ZnO-100% polyester textile composite materials treated through a padding process with different concentrations of ZnO dispersions as active agent in water and methanol were studied. The results show that 3% ZnO-textile composite material have enhanced water barrier properties compared with the other compositions; a fact which promises improved properties in terms of comfort. ZnO modification of polyester surfaces leads to a dramatic decre…