Search results for "COMPOSITE"
showing 10 items of 4584 documents
Asymmetric synthesis of 3,3′-pyrrolidinyl-dispirooxindoles via a one-pot organocatalytic Mannich/deprotection/aza-Michael sequence
2016
Chemical communications 52, 2249-2252 (2016). doi:10.1039/C5CC10057G
Luminescent CdSe Quantum Dot Arrays for Rapid Sensing of Explosive Taggants
2022
Chemical sensors based on fluorescent quantum dots have attracted intense interest because of their excellent optical and electronic properties compared to the routinely employed fluorescent organic dyes. This study reports a CdSe QD-polymer-based luminescent chemosensor, which is based on an array containing either green-emitting or red-emitting CdSe QDs embedded in polycaprolactone as a polymer host matrix. We evaluate the sensing capability of the nanocomposites by exposing both sensors to vapors of explosive taggants, explosive-like molecules, and some common solvents. Both nanocomposites exhibit a very fast response time of <30 s. The limit of detection of the sensors for 3-nitrotoluen…
Green Composites Based on PLA and Agricultural or Marine Waste Prepared by FDM
2021
Three dimensional-printability of green composites is recently growing in importance and interest, especially in the view of feasibility to valorize agricultural and marine waste to attain green fillers capable of reducing bioplastic costs, without compromising their processability and performance from an environmental and mechanical standpoint. In this work, two lignocellulosic fillers, obtained from Opuntia ficus indica and Posidonia oceanica, were added to PLA and processed by FDM. Among the 3D printed biocomposites investigated, slight differences could be found in terms of PLA molecular weight and filler aspect ratio. It was shown that it is possible to replace up to 20% of bioplastic …
Comparison of the shear bond strength of 3D printed temporary bridges materials, on different types of resin cements and surface treatment
2019
Background Thus, purpose of this study was to compare the shear bond strength of the resin cement and the resin modified glass ionomer cement on 3D printed temporary material for crowns and bridges in combination with different surface treatment modalities. Material and methods Test specimens VarseoSmile Temp material (Bego, Bremen, Germany) (n=64) in the form of rectangular blocks (n=32) and cylindrical test specimens (n=32) were printed using the Varseo S 3D printer (Bego, Bremen, Germany). The specimens were divided into 4 groups, with 8 specimens of each kind. Two groups (n=16 pairs) were blasted with Perlablast® Micro [PM] 50µm (Bego, Bremen, Germany) and two groups (n=16 pairs) were b…
Synthesis and Solution Processing of Nylon‐5 Ferroelectric Thin Films: The Renaissance of Odd‐Nylons?
2020
Investigation of charge ratio variation in mRNA – DEAE-dextran polyplex delivery systems
2019
Biomaterials 192, 612 - 620 (2019). doi:10.1016/j.biomaterials.2018.10.020
Sheet Bending Modelling for AA 5083 Aluminium Alloy
1995
An extensive investigation of the V- and U-die bending processes of AA 5083 aluminium alloy has been performed by means of the finite element method and the experimental tests. The predicted results, in terms of elastic springback and loads, were compared with the experimental ones in similar conditions. At a given punch stroke, the springback ratio K increases with the sheet thickness, and, at a constant sheet thickness, K increases with the punch stroke. The comparison between predicted and experimental K values shows an excellent agreement in all the ranges of punch stroke and sheet thickness investigated. A very good agreement between the predicted bending forces and the experimental on…
A Multilayered Plate Theory with Transverse Shear and Normal Warping Functions
2016
A multilayered plate theory which takes into account transverse shear and normal stretching is presented. The theory is based on a seven-unknowns kinematic field with five warping functions. Four warping functions are related to the transverse shear behaviour, the fifth is related to the normal stretching. The warping functions are issued from exact three-dimensional solutions. They are related to the variations of transverse shear and normal stresses computed at specific points for a simply supported bending problem. Reddy, Cho-Parmerter and (a modified version of) Beakou-Touratier theories have been retained for comparisons. Extended versions of these theories, able to manage the normal s…
Stress-strain analysis of specimens subjected to tensile loading during moisture uptake
2015
Abstract: A robust and efficient numerical method for the calculation of the internal stress state that develops within structures subjected to mechanical and steady state or transient hygroscopic loading conditions, has been developed. The method encompasses a layer by layer approach whereby the structure is discretised into plies with different material properties corresponding to the different ply moisture content. The proposed method has been validated against finite element solutions, and results from its application on a fully characterised EDT (technical name) polymer binder are presented. The impact of the moisture induced viscoelastic behaviour on the structural response of the cas…
Permeability of three-dimensional random fiber webs
1998
We report the results of essentially ab initio simulations of creeping flow through large threedimensional random fiber webs that closely resemble fibrous sheets such as paper and nonwoven fabrics. The computational scheme used in this Letter is that of the lattice-Boltzmann method and contains no free parameters concerning the properties of the porous medium or the dynamics of the flow. The computed permeability of the web is found to be in good agreement with experimental data, and confirms that permeability depends exponentially on porosity over a large range of porosity. [S0031-9007(97)05087-4]