Search results for "SIMULATION"
showing 10 items of 5095 documents
Protein corona composition of poly(ethylene glycol)- and poly(phosphoester)-coated nanoparticles correlates strongly with the amino acid composition …
2017
Extensive molecular dynamics simulations reveal that the interactions between proteins and poly(ethylene glycol) (PEG) can be described in terms of the surface composition of the proteins. PEG molecules accumulate around non-polar residues while avoiding the polar ones. A solvent-accessible-surface-area model of protein adsorption accurately fits a large set of data on the composition of the protein corona of poly(ethylene glycol)- and poly(phosphoester)-coated nanoparticles recently obtained by label-free proteomic mass spectrometry.
Manganese iron oxide superparamagnetic powder by mechanochemical processing. Nanoparticles functionalization and dispersion in a nanofluid
2012
Manganese ferrite nanoparticles were synthesized using a High-Energy Ball-Milling mechanochemical method. After 1 h of milling, the process produces a material consisting of single crystalline domain nanoparticles having a diameter of about 8 nm. Chemical properties of the synthesized powders allow an easy functionalization with citric acid. Both as-obtained and functionalized samples show superparamagnetic behaviour at room temperature, and the functionalized powder is stably dispersible in aqueous media at physiological pH. The average hydrodynamic diameter is equal to similar to 60 nm. Nanoparticles obtained by the reported High-Energy Ball-Milling method can be synthesized with high yie…
A Numerical Study on Interlaminar Defects Characterization in Fibre Metal Laminates with Flying Laser Spot Thermography
2018
This work describes a numerical study on non-destructive evaluation of interlayer disbond defects in aerospace grade Fibre Metal Laminate sheets (FMLs). A recently proposed infrared non-destructive testing setup is considered, where a continuous laser is moved over the material surface, while the thermal footprint of the moving heat source is acquired, e.g. by an infrared thermal camera. Interlayer disbonds are then detected by analysing the features of the acquired thermograms. The experimental feasibility of this approach has been recently proved. The present work proposes a numerical simulation of the NDT approach, where the material thermal response is analysed and correlated to defects…
Octave-spanning ultraflat supercontinuum with soft-glass photonic crystal fibers
2009
We theoretically identify some photonic-crystal-fiber structures, made up of soft glass, that generate ultrawide (over an octave) and very smooth supercontinuum spectra when illuminated with femtosecond pulsed light. The design of the fiber geometry in order to reach a nearly ultraflattened normal dispersion behavior is crucial to accomplish the above goal. Our numerical simulations reveal that these supercontinuum sources show high stability and no significant changes are detected even for fairly large variations of the incident pulse. Ministerio de Ciencia e Innovación (TEC2008-05490) and Generalitat Valenciana (GV/2007/043).
Deformation analysis of ATHENA test filters made of plastic thin films supported by a mesh under differential static pressure
2019
Within ESA Cosmic Vision 2015-2025 Science Program, ATHENA was selected to be a Large-class high energy astrophysics space mission. The observatory will be equipped with two interchangeable focal plane detectors named X-Ray Integral Field Unit (X-IFU) and Wide Field Imager (WFI). In order to optimally exploit the detector sensitivity, X-ray transparent filters are required. Such filters need to be extremely thin to maximize the X-ray transparency, that is, no more than a few tens of nm, still they must be able to sustain the severe stresses experienced during launch. Partially representative test filters were made with a thin polypropylene film, coated with Ti, and supported by a thin highl…
Comparison of 3D structural characteristics of high and low resolution X-ray microtomographic images of paper
2005
The detailed 3D structure of paper was revealed applying both high and low resolution X-ray microtomography. The qualityof the two techniques with respect to resolution and volume size was compared by measuring various structural andtransport properties of the digital volumes.
Nanoscale oxide growth on Al single crystals at low temperatures: Variable charge molecular dynamics simulations
2006
We investigate the oxidation of aluminum low-index surfaces [(100), (110), and (111)] at low temperatures (300-600 K) and three different gas pressure values. We use molecular dynamics (MD) simulations with dynamic charge transfer between atoms where the interaction between atoms is described by the Es+ potential composed of the embedded atom method (EAM) potential and an electrostatic contribution. In the considered temperature range and under different gas pressure conditions, the growth kinetics follow a direct logarithmic law where the oxide thickness is limited to a value of ∼3 nm. The fitted curves allow us to determine the temperature and the pressure dependencies of the parameters i…
Large deflection of magneto-electro-elastic laminated plates
2014
Abstract A model for the large deflection analysis of magneto-electro-elastic laminated plates is derived. The first order shear deformation theory and the von Karman stress function approach are employed. A set of resolving partial differential equations involving kinematical variables and the stress function is obtained as a consequence of the preliminary condensation of the electro-magnetic state to the plate kinematics. A closed form solution for simply-supported plates is presented. Numerical results are carried out for plates consisting of piezoelectric BaTiO 3 and piezomagnetic CoFe 2 O 4 layers. These results show the influence of large deflections on the plate response and could be…
Study of the glow curves of TLD exposed to thermal neutrons.
2007
The glow curves of thermoluminescent dosimeters (TLD600, TLD700 and MCP), exposed to a mixed field of thermal neutrons and gamma photons are analysed. The fluence values of thermal neutrons used, comparable with those used in radiotherapy, allow one to define the reliability of the TLDs, in particular the most sensitive MCP, in this radiation field and to get information on the dose absorbed values. The glow curves obtained have been deconvoluted using general order kinetics and the observed differences for the different LET components have been analysed. In particular, the ratio of the n(0) parameter of two different peaks seems to allow to discriminate the different contributions of neutr…
Buckling of a coating strip of finite width bonded to elastic half-space
2008
AbstractA solution for buckling of a stiff strip of finite width bonded to a compliant elastic half-space and subjected to uniform axial compression is presented. Approximate semi-analytical and finite element solutions are obtained and compared with a two-dimensional case of a plate on elastic foundation. The comparison demonstrates that the two-dimensional solution can be applied to predict the buckling wavelength and critical compressive strain when the width of the strip is equal to or larger than the buckling wavelength. For narrow strips, the wavelength is smaller and critical strain is higher than that of a plate on foundation.