Search results for "Matrix"
showing 10 items of 3205 documents
Huntington and the liberal thought. Problems of Anglo-democracy to understand politics
2013
The liberal thought has inspired philosophy and sociology during years. From its view, US has two main goals. One is to expand the civilized culture to other non-western countries, and second to grant the democratic values. Paradoxically, terrorism poses one of the most troubling aspects of contemporanean democracy. On one hand, not only it defies the democratic resources to anticipate the next blow, but also put US to conduct one-sided attacks to autonomous countries. To legitimize the expansion of this new imperial order, the liberal discourse appealed to two strategies: first and foremost, denoting pejoratively as the case of Latin America that there is a cultural matrix that impedes the…
Biodegradable tablets having a matrix of low molecular weight poly-L-lactic acid and poly-D,L-lactic acid.
1990
Biodegradable Homo- and Copolymers of lactic and glycolic acids have been used for manufacture of microparticles and matrix implants1,5). To ensure sufficient hydrolytic matrix stability lactic acids of high and medium degree of polymerization have been used. The manufacture of poly lactic acid tablets with an average molecular weight of 25000 and 6000 was reported recently, after finishing the following study2). Bioabbaubare Gerusttabletten aus niedermolekularer poly-L-Milchsaure und poly-D,L-Milchsaure
SPIONs embedded in polyamino acid nanogels to synergistically treat tumor microenvironment and breast cancer cells.
2018
Abstract The extremely complex tumor microenvironment (TME) in humans is the major responsible for the therapeutic failure in cancer nanomedicine. A new concept of disease-driven nanomedicine, henceforth named “Theranomics”, which attempts to target cancer cells and TME on the whole, represents an attractive alternative. Herein, a nanomedicine able to co-deliver doxorubicin and a tumor suppressive proteolytic protein such as collagenase-2 was developed. We successfully obtained superparamagnetic nanogels (SPIONs/Doco@Col) via the intermolecular azide-alkyne Huisgen cycloaddition. We demonstrated that a local ECM degradation and remodeling in solid tumors by means of collagenase-2 could enha…
Durability of basalt/hemp hybrid composites
2017
This study focused on the performance of injection-molded short hemp fibre and hemp/basalt fibre hybrid high density polyethylene composites. Results showed that hybridization with basalt fibre enhanced the performance properties. Analysis of fiber length distribution in the composite and fracture surface was performed to study the fiber breakage and fracture mechanism. Prolonged moisture absorption and accelerated ageing of short hemp fibre and hemp-basalt hybrid reinforced thermoplastic composites was addressed. Ageing in water did not result in a reduction of the strength of the composite samples, while it was found to decrease stiffness of hemp fibre reinforced composites. Mechanical pr…
Multi-functional hindered amine light stabilizers-functionalized carbon nanotubes for advanced ultra-high molecular weight Polyethylene-based nanocom…
2015
Hindered Amine Light Stabilizer (HAS) molecules have been covalently linked on the outer surface of multi-walled carbon nanotubes (CNTs), and the so-obtained multi-functional fillers (HAS-f-CNTs) have been compounded with Ultra High Molecular Weight Polyethylene (UHMWPE) to get composite films. The success of the grafting reaction of the HAS molecules has been confirmed through spectroscopic and thermo-gravimetric analyses. Morphological analyses reveal a segregated microstructure, in which CNT-rich channels surround the polymer domains. This morphology results in improved mechanical properties and appreciable electrical conductive features. More importantly, the addition of only 1 wt.% of …
Effect of moisture on elastic and viscoelastic properties of epoxy and epoxy-based carbon fibre reinforced plastic filled with multiwall carbon nanot…
2016
Abstract In this study, we investigated the peculiarities of moisture absorption and moisture-induced effects on the elastic and viscoelastic flexural properties of epoxy resin and carbon fibre reinforced plastic (CFRP) filled with multiwall carbon nanotubes (MWCNTs). Short-term cyclic creep-recovery tests of moistened epoxy and CFRP filled with MWCNTs revealed improvements in creep resistance for both materials. The addition of MWCNTs to the epoxy resin suppressed the moisture absorption by the material, causing a reduction in the diffusion coefficient by 31% and equilibrium moisture content by 15%. The addition of MWCNTs reduced the flexural strength of moistened epoxy and CFRP samples by…
Effect of external basalt layers on durability behaviour of flax reinforced composites
2016
Abstract Aim of this work is to evaluate the influence of external layers of basalt-mat on the durability behaviour of flax reinforced epoxy composites. To this scope, long-term ageing tests were performed on two different laminates in critical environmental conditions. The first laminate, named Flax, was constituted by stacking ten layers of bidirectional flax fabrics. The second one, named Flax–Basalt, was produced by replacing two external flax layers with two layers of basalt mat for each side of the laminate. Both laminates were exposed to salt-fog environmental conditions, according to ASTM B 117 standard, for 60 days. Five samples per laminate were removed from salt-fog spray chamber…
Damage accumulation in a carbon/epoxy composite : Comparison between a multiscale model and computed tomography experimental results
2012
International audience; High-resolution computed tomography has been carried out for carbon/epoxy laminates loaded in situ to failure. The experimental data allows major damage mechanisms to be quantified in 3D, in an unambiguous and mechanically representative way, where previous experimental analysis is limited. A multi-scale model that predicts damage accumulation in tensile loaded composites is compared to the experimental analysis, to validate the underpinning assumptions within the model and overall performance. The model considers the random nature of fibre-strengths, stress transfer resulting from fibre breaks, fibre/matrix debonding and viscosity of the matrix. Assumptions within t…
Advanced piezoresistive sensor achieved by amphiphilic nanointerfaces of graphene oxide and biodegradable polymer blends
2018
This work focuses on the preparation of a piezoresistive sensor device, by exploiting an amphiphilic sample of graphene oxide (GO) as a compatibilizer for poly (lactic acid) (PLA)-Poly (ethylene-glycol) (PEG) blends. The presence of GO determined a high stiffening and strengthening effect, without affecting toughness, and allowed a good stability of mechanical properties up to 40 days. Moreover, GO endowed the materials with electrical properties highly sensitive to pressure and strain variations: the biodegradable pressure sensor showed a responsivity of 35 μA/MPa from 0.6 to 8.5 MPa, a responsivity around 19 μA/MPa from 8.5 to 25 MPa. For lower pressure values (around 0.16–0.45 MPa), inst…
A simple method to interpret the rheological behaviour of intercalated polymer nanocomposites
2016
Abstract Nanocomposites are a new class of polymer composites that exhibit an interesting combination of chemical, physical, thermal and mechanical properties. Only small amounts of nanofiller are sufficient to generate great variations of many properties. This work focuses on the rheological behaviour of the intercalated polymer nanocomposites in shear flow. The increase of the viscosity and the more pronounced non-Newtonian behaviour is interpreted simply considering the increase of volume of the inert phase caused by the intercalation of the macromolecules. Indeed, the volume of the intercalated tactoids increases with increasing the interlayer distance. On the other hand, the interlayer…