Search results for " COMPOSITES"
showing 10 items of 1620 documents
Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre compo…
2016
The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro-mechanical model. The parameters characterizing the microstructure of the composites, e.g. fibre length and orientation distributions, used as input in the model were obtained by micro-tomography. The investigation was carried out on composites with untreated and surface treated fibres with various fibre weight contents (5wt%, 10wt%, and 15wt% for untreated fibres, and 15wt% for treated fibres). The…
Growth, single crystal investigation, hirshfeld surface analysis, DFT studies, molecular docking, physico-chemical characterization and, in vitro, an…
2021
Abstract Interaction of the diphosphoric acid (H4P2O7) and organic ligand (3.4-dimethylaniline) with transition metal ions, cobalt (II) chloride leads to the formation of novel stable Co(II)-diphosphate cluster with empirical formula (C8H12N)2[Co(H2P2O7)2(H2O)2].2H2O. The structure of the synthesized material was confirmed by single crystal XRD at 120 K. The crystal was plate and crystallized in the triclinic P 1 ¯ space group with a = 7.5340(4) A, b = 7.5445(4) A, c = 13.6896(8) A, α = 84.215(5)°, β = 76.038(5)°, γ = 74.284(5)°, V = 726.38(7) A3 and Z = 1. Full-matrix least-squares refinement converged at R = 0.035 and Rw = 0.088 for 3636 independent observed reflectio…
Impact of point defects on the elastic properties of BaZrO3: Comprehensive insight from experiments and ab initio calculations
2018
Abstract Acceptor doped BaZrO3 is the prototype of proton conducting perovskites which are of strong interest as electrolytes for intermediate temperature fuel cells. Elastic properties of both dry and hydrated Y-doped BaZrO3 (1.5–17 mol% Y) were determined using ultrasound time of flight (TOF) measurements, and complemented by ab initio calculations which allow for an analysis of the different contributions. The experimental and theoretical findings are consistent and reveal a strong decrease of the Young's, shear and bulk moduli upon increasing dopant concentration. This decrease is attributed to a combined effect of (i) macroscopic lattice chemical expansion mainly caused by differing io…
Ionizing radiation-engineered nanogels as insulin nanocarriers for the development of a new strategy for the treatment of Alzheimer's disease
2016
A growing body of evidence shows the protective role of insulin in Alzheimer's disease (AD). A nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for Alzheimer's Disease (AD), is designed and synthetized. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation is chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility and hemocompatibility of the naked carrier is demonstrated. The insulin conjugated to the NG (NG-In) is protected by protease degradation and able to bind to insulin receptor (IR), as demonstrated by immunofl…
Raman and IR investigation of silica nanoparticles structure
2013
Abstract In the present investigation we report experimental data regarding the Raman and Infra-Red (IR) absorption activities of commercial silica nanoparticles. We compared the data of the nanoparticles with the ones acquired in the same experimental conditions for commercial bulk silica. By this comparison we highlighted that the variability of the spectral features of the matrix related Raman and IR bands in the nanoparticles is above the one observed for the bulk systems before any treatments. Furthermore, by studying nanoparticles with different sizes (diameters from 40 to 7 nm) and applying the shell-model we can suggest that the core network of the nanoparticles is close to the one …
Effect of graphene and fabrication technique on the release kinetics of carvacrol from polylactic acid
2019
Abstract Porous membranes and thin films containing poly-lactic acid (PLA), carvacrol (CRV) and graphene nanoplatelets (GNP) were fabricated by electrospinning and solvent casting at different formulations. The systems were characterized from a mechanical, morphological, calorimetric and spectroscopic point of view. CRV release as a function of time was studied and a mathematical model was used to fit and interpret the data in order to investigate the release mechanism. The results indicate that the incorporation of GNP generally determined a simultaneous strengthening, stiffening and toughening effect, while preserving a good ductility. Furthermore, integrating GNP allowed tuning the amoun…
Transient absorption and luminescence of LiNbO3 and KNbO3
2001
Abstract The results of time-resolved optical absorption spectra in congruent and stoichiometric LiNbO3 as well as KNbO3 crystals are reported. The role of different polaron types in transient absoiption and luminescence spectra and decay kinetics are discussed.
Kinetics of Photorefractive Light Scattering in LiNbO3:Cu and LiNbO3:Zn Single Crystals
2011
Results of studies of the kinetics of photorefractive light scattering (PRLS) in optically nonlinear congruent single crystals of lithium niobate (LiNbO3, Li/Nb = 0.946) containing multivalent cation admixtures of Cu [0.015 mass %] (“photorefractive”) and Zn [0.5 mass %] (“non-photorefractive”) are reported. The shape of the PRLS indicatrix is found to be different in case of Cu and Zn admixtures. However, the angular widening of the indicatrix in both cases reaches its stationary value faster at higher laser radiation intensities. The PRLS is found to depend on the site of the ingot from which the samples are cut – an evidence of non-uniform distribution of defects with localised electrons…
Heat transfer in semi-transparent materials during laser interaction
2004
Abstract A model of energy exchange, based on the finite element method is specially developed to determine the thermal field for semi-transparent polymers irradiated by laser. Our model, which uses the finite element method, allows to define the laser and specific structure characteristics in terms of density of power, speed and shape of the spotlight, material coefficient absorption, etc. The model has been experimentally validated by measuring the thermal response induced by the laser source. The experimental part of the study has been performed using a semiconductor laser diode source and an infrared thermography camera.
Analysis of stress concentration during tension of round pultruded composite rods
2008
The stress state in a solid round transversely isotropic rod loaded with balanced shear stresses on a part of its lateral surface is considered. The change in gripping conditions is simulated by varying the distribution of statically equivalent shear stresses. The solution for the stress state was obtained using exact equations of linear theory of elasticity of anisotropic body. An analysis of the distribution of longitudinal and hoop stresses showed that at the grip edges a very high stress concentration is possible, which depends on the radius of the tensioned rod and the distribution of shear stresses on the gripped surface. At the grip edges, the longitudinal and hoop stresses tend to i…