Search results for "FLE"
showing 10 items of 3517 documents
Mesocrystalline calcium silicate hydrate: A bioinspired route toward elastic concrete materials
2017
Controlled aggregation of polymer-stabilized calcium silicate hydrate nanoparticles leads to elastic cementitious materials.
Mechanical, thermal and electrical properties of monolayer and bilayer graded Al/SiC/rice husk ash (RHA) composite
2017
Abstract The mechanical, electrical and thermal properties as well as thermal expansion of Al/SiC/RHA (rice husk ash) monolayer and bilayer composite have been studied using the Taguchi method and analysis of variance (ANOVA). The parameter that most significantly affects the modulus of elasticity of Al/SiC/RHA bilayer composites is processing time, with contribution percentages of 68 and 27% calculated from stress-strain graphs and ultrasonic method, respectively. However, the factor which mostly affects bending strength, CTE value and electrical resistivity of composites is process temperature with contribution percentages of 32, 28, and 22%, respectively. The projected values for modulus…
Analytical Refinement of Sandwich Plate Bending Problem Considering Local Effects-I
1999
Analytic expressions for local flexural characteristics and stresses of sandwich panels under loading by point forces have been found. A discrete-layer model for bending of a three-layer panel with a soft filler is proposed. Contractility of a normal in the model is deduced in terms of a difference between deflections of face layers. The accountability of transverse shear in the filler and the sheets is deduced on piecewise rotation of the normal. Equations of the model having four degrees of displacement freedom are of twelfth order. The specific features of the stress from point forces in cylindrical bending are considered using the operational Laplace method with the generalized Dirac f…
Mechanical properties of Macadamia nutshell powder and PLA bio-composites
2016
AbstractA study on the mechanical properties of Macadamia nutshell powder/PLA bio-composites is presented in this paper. The effects of powder weight content, powder condition and processing methods are investigated with the aid of Design of Experiments. It is shown from the results that both the stiffness and strength are dependent on the weight content of Macadamia nutshell powders. The elastic modulus increases 9.8% when the Macadamia nutshell powder content is 40%. Both flexural and tensile strengths decrease with increasing Macadamia nutshell powder content. On average, when the Macadamia nutshell powder content is 40%, the decreases in the flexural and tensile strengths are 42 and 63%…
Tunable optical sectioning in confocal microscopy by use of symmetrical defocusing and apodization
2008
We present two novel optical methods to achieve a significative improvement in the optical-sectioning capacity of confocal scanning microscopes. The techniques, whose real power is the simplicity with which they can be implemented, consist of a suitable combination of symmetrical defocusing with two different manners of apodizing both parts of the confocal architecture. It is shown that the proposed techniques are useful in both the bright-field and the fluorescence modes and for reflection and transmission geometries.
Colloidal plasmonic back reflectors for light trapping in solar cells.
2014
A novel type of plasmonic light trapping structure is presented in this paper, composed of metal nanoparticles synthesized in colloidal solution and self-assembled in uniform long-range arrays using a wet-coating method. The high monodispersion in size and spherical shape of the gold colloids used in this work allows a precise match between their measured optical properties and electromagnetic simulations performed with Mie theory, and enables the full exploitation of their collective resonant plasmonic behavior for light-scattering applications. The colloidal arrays are integrated in plasmonic back reflector (PBR) structures aimed for light trapping in thin film solar cells. The PBRs exhib…
“Ab-initio” structure solution of nano-crystalline minerals and synthetic materials by automated electron tomography
2012
Most of the newly discovered mineral phases, as well as many new synthesized industrial materials, appear only in the form of nano crystals, with a size not sufficient for single-crystal x-ray structure analysis. The development of techniques able to investigate the structure of nano crystalline materials is therefore one of the most important frontiers of crystallography. The most widespread technique providing relatively fast and well consolidated routes for structure analysis of bulk materials is x-ray powder diffraction (XRPD). Nevertheless, XRPD suffers from intrinsic 1-dimension reduction of information that greatly limits its applicability in presence of peak broadening and overlappi…
PLA based biocomposites reinforced with Arundo donax fillers
2014
Abstract In this work, for the first time, a natural and almost inexpensive filler obtained by grinding the culms of Arundo donax was used to prepare PLA based biocomposites. The composites were prepared by melt compounding PLA with A. donax filler (ADF). The influence of the content and size of ADF on the morphology and on the mechanical and thermal properties of PLA–ADF composites was evaluated. Moreover, ADF was extracted from composites to evaluate the effect of processing on morphology and dimensions of the incorporated filler. Furthermore, the experimental elastic moduli of the biocomposites have been fitted, employing two theoretical models, i.e., Hill and Halpin–Tsai. The results sh…
Electrical and optical low frequency noises in multimodal vertical cavity surface emitting lasers
2006
Experimental investigations of the low frequency noise of multimode 780 nm vertical cavity surface emitting lasers are reported. Electrical noise, optical noise and their correlation have been measured in the frequency range 1 Hz–95 kHz. The results show that the main contribution to the electrical noise is located in the distributed Bragg reflector layers of the laser. The optical power and pump current noise sources are strongly correlated below and around the threshold, while are weakly correlated above threshold. It is argued that the noise in the optical power is due to both free injection carrier noise and optical gain fluctuations.
N-TiO2 Photocatalysts highly active under visible irradiation for NOX abatement and 2-propanol oxidation
2013
N-doped TiO2 powders were prepared by two different sol-gel methods. Samples were characterised by X-ray diffraction (XRD), BET specific surface area measurements (SSA), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and Electron Paramagnetic Resonance (EPR). XPS measurements revealed a signal at 400 eV assignable to nitrogen in the form of Ti-N-O. EPR signals are attributed to molecular NO trapped with cavities/defects possibly interacting with oxygen vacancies. The photocatalytic activity under UV and visible light was determined following the abatement of NOx and the photodegradation of 2-propanol in gas-solid systems. N…