Search results for "strength"
showing 10 items of 2415 documents
Preparation and characterization of polyamide 6/polyethylene blend-clay nanocomposites in the presence of compatibilisers and stabilizing system
2010
Abstract Several compatibilising systems were added to high-density polyethylene (HDPE) and polyamide 6 (PA6) blends in the presence of an organically modified montmorillonite (OMM). All the blends were prepared by using a co-rotating twin-screw extruder and characterized by SEM, TEM and XRD analyses. In addition, the rheological behaviour and the mechanical properties – tensile and impact – were evaluated. The presence of OMM affects the dimensions of the polymeric phases in the blend but not their mutual adhesion, granted only by the compatibilisers. TEM, SEM and XRD analyses indicated that there is a strict correlation between the compatibilisation level and the final interlayer distance…
Mechanical, degradation and drug-release behavior of nano-grained Fe-Ag composites for biomedical applications.
2018
Abstract An original fabrication route of high-strength bulk Fe-5Ag and Fe-10Ag nanocomposites with enhanced degradation rate is reported. Near fully dense materials with fine nanostructures and uniform distribution of Ag nanoparticles were obtained employing high energy attrition milling of Fe-Ag2O powder blends followed by cold sintering – high pressure consolidation at ambient temperature that allowed the retention of the nanoscale structure. Annealing in hydrogen flow at 550 °C resulted in enhanced ductility without coarsening the nanostructure. The strength in compression of Fe5Ag and Fe10Ag nanocomposites was several-fold higher than the values reported for similar composites with mic…
Mapping the 3D-surface strain field of patterned tensile stainless steels using atomic force microscopy.
2005
Abstract The quantification of microstructural strains at the surface of materials is of major importance for understanding the reactivity of solids. The present paper aims at demonstrating the potentialities of the atomic force microscopy (AFM) for mapping the three-dimensional surface strain field on patterned tensile specimens. Electron beam (e-beam) lithography has been used to deposit 16×16 arrays of gold-squared pads. Monitoring the evolution of such a pattern under applied strain allows to quantify the triaxial strains both at the micro-(plastic) domain and nanoscale (elastic) domain vs. applied strain. The proposed method was applied to stainless steels after 4.5% plastic strain.
Carboxymethylation of alkali extracted xylan for preparation of bio-based packaging films
2012
This study describes the synthesis of carboxymethylxylan (CMX) and investigates its suitability as a film for packaging applications. High-purity polymeric xylan was extracted from commercial bleached birch kraft pulp and converted to CMX with three different degrees of substitution (DSs). The water vapor sorption, mechanical, and barrier properties of the films prepared from CMX were tested. Increasing DS of CMX films resulted in an increase in elongation at break and a decrease in tensile strength and Young's modulus. The DS also affected the barrier properties of the films. CMX films with higher DS showed improved (reduced) oxygen permeability (OP), and the water vapor permeability (WVP)…
Electric breakdown of dielectric thin films for high-voltage display applications
2016
Smectic A liquid crystal is one of the most promising material for smart glass application due to infinite bistability and low haze at clear state. Voltage is needed to switch from scattering to transparent and it is likely for dielectric breakdown to occur. In order to reduce the probability of dielectric breakdown to occur, a dielectric insulating coating is usually employed. In this work we have compared electrical and optical properties of SiO2 thin films with thickness up to 500 nm coated by flexographic printing and reactive magnetron sputtering. IV characteristics and dielectric breakdown values show sputtered coatings to have higher dielectric strength. For sputtered coatings with t…
Structure-property relationship of PLA-Opuntia Ficus Indica biocomposites
2019
Abstract In this work, a lignocellulosic flour was achieved by grinding the cladodes of Opuntia Ficus Indica and then added to a poly-lactic acid (PLA) in order to prepare biocomposites by melt processing. The influence of filler content and size on the morphological, rheological, and mechanical properties of the green composites was assessed. Moreover, solvent-aided filler extraction enabled to evaluate the homogeneity of filler dispersion, as well as the effect of processing on the geometrical features of the fillers. The experimental data obtained by tensile tests proved to be remarkably higher than those predicted by Halpin–Tsai model, presumably due to the capability of the polymer to …
Influence of adhesive systems on microtensile bond strength of resin-based endodontic sealers to the root dentin
2014
Objective: The aim of this study was to determine the microtensile bond strength to root dentin of AH PlusTM and EndoREZ® with Clearfil Liner Bond 2V and Optibond SoloTM Plus adhesive systems. Study Design: The coronal and middle thirds of six single rooted bovine teeth was split longitudinally in a mesio- distal direction. The two halves were joined with AH Plus or EndoREZ, with and without the use of Clearfil Li - ner Bond 2V and Optibond SoloTM Plus adhesive systems. Build-ups were vertically sectioned into quadrangular (?1mmx1mm) compound bars and subjected to tensile tests at a constant crosshead speed (1 mm/min) until debon - ding. Results: Optibond ® Solo PlusTM in combination with A…
Optical absorption and electron paramagnetic resonance of theEα′center in amorphous silicon dioxide
2008
We report a combined study by optical absorption (OA) and electron paramagnetic resonance (EPR) spectroscopy on the E{sub {alpha}}{sup '} point defect in amorphous silicon dioxide (a-SiO{sub 2}). This defect has been studied in {beta}-ray irradiated and thermally treated oxygen-deficient a-SiO{sub 2} materials. Our results have pointed out that the E{sub {alpha}}{sup '} center is responsible for an OA Gaussian band peaked at {approx}5.8 eV and having a full width at half maximum of {approx}0.6 eV. The estimated oscillator strength of the related electronic transition is {approx}0.14. Furthermore, we have found that this OA band is quite similar to that of the E{sub {gamma}}{sup '} center in…
A methodology for the rapid characterization of Mode II delamination fatigue threshold in FRP composites
2019
Abstract A new methodology to measure the Mode II interlaminar fracture in fatigue for FRP composites is developed. The proposed methodology uses a Modified Transvers Crack Tensile (MTCT) specimen and is able to characterize the near threshold behavior in a robust, easier and significantly faster way than standard procedures. Analytical formulae, able to link the crack growth rate to the load or strain amplitudes, were found and verified, and their importance was explained, in particular, for what concerns the characterisation of the near threshold behavior. Experiments were performed both in load and strain control, while the delamination growth was monitored using different techniques inc…
Optical properties of exciton confinement in spherical ZnO quantum dots embedded in matrix
2009
Abstract The optical characteristics of ZnO nanoparticles in SiO2 matrix have been determined by UV–visible and photoluminescence (PL) studies. The PL spectrum of the ZnO quantum dots shows two different bands: the first one is a broad green emission band related to deep level emission in the visible range and the second one is situated at 3.48 eV in the ultraviolet region, and is attributed to the recombination of electrons in the conduction band and holes in the valence band. The experimental result that we found was simulated numerically using different methods. Our calculations revealed a good agreement between the matrix element calculation method and the experimental result. We have a…