Search results for " interphase"

Effect of reducing agents on the acidification capacity and the proton motive force of Lactococcus lactis ssp. cremoris resting cells.

2002

International audience; Reducing agents are potential inhibitors of the microbial growth. We have shown recently that dithiothreitol (DTT), NaBH(4) and H(2) can modify the proton motive force of resting cells of Escherichia coli by increasing the membrane protons permeability [Eur. J. Biochem. 262 (1999) 595]. In the present work, the effect of reducing agents on the resting cells of Lactococcus lactis ssp. cremoris, a species widely employed in dairy processes was investigated. DTT did not affect the acidification nor the DeltapH, in contrast to the effect previously reported on E. coli. The DeltaPsi was slightly increased (30 mV) at low pH (pH 4) in the presence of 31 mM DTT or 2.6 mM NaB…

A novel approach to prevent graphene oxide re-aggregation during the melt compounding with polymers

2015

Abstract The technology for the preparation of polymer-GO nanocomposites was investigated by studying the structure-properties relationships of two different systems, based on PA6 and EVA, fabricated by using different preparation methods, i.e. melt mixing, wet phase inversion, and the combination of the two. The morphology of nanocomposites resulted dramatically influenced by the technique adopted and showed to be the critical variable affecting the physical properties of the materials. Finally, the mechanical and dynamic-mechanical of the nanocomposites were improved by using the hybrid technique combining the two procedures.

Fundamentals of photoelectrocatalysis

2022

Photoelectrocatalysis combines heterogeneous photocatalysis and electrocatalysis principles for numerous processes including the degradation of harmful compounds, the generation of H2 and O2 from water splitting, the reduction of CO2 or the photoelectrocatalytic synthesis of valuable organic molecules otherwise difficult to be synthetized with classical approaches. The recent progress of photoelectrocatalysis is heavily related to the development of materials, especially in 2D and nano materials. Highly ordered nanomaterials such as graphene, nanotubes, nanowires, etc. are gaining more attention due to their high surface area and excellent conductivity. Other challenges are the development …

Modelling the structure-property relationships of high performance PBAT-based biocomposites with natural fibers obtained from Chamaerops humilis dwar…

2022

Two fibrous fillers were achieved from stalks and leaves of Chamaerops humilis dwarf palm and tested as reinforcing agents for poly(butylene adipate co-terephthalate) (PBAT)-based composites. The influence of filler type and content on the morphomechanical properties of the green composites was assessed. The outcomes of tensile tests pointed out that both fillers are strong candidates to overcome the two main limiting aspects of PBAT, that is, the lack of both stiffness and cost-effectiveness, while preserving its stretchability and environmental sustainability. The remarkable stiffness increments (up to 300%), combined with fair retention of stretchability (33%) and doubled resistance, led…

The interphase model applied to simulate chemically bonded anchors

2009

CuO nanoparticle filled vinyl-ester resin nanocomposites: Fabrication, characterization and property analysis

2007

Abstract Both unmodified cupric oxide (CuO) nanoparticles and those functionalized with a bi-functional coupling agent methacryloxypropyl-trimethoxysilane (MPS) were used to fabricate vinyl-ester resin polymeric nanocomposites. The nanoparticle functionalization was observed to have a significant effect on the physical properties of the cupric oxide filled vinyl-ester resin nanocomposite. Thermal degradation study by thermo-gravimetric analysis (TGA) showed the increased thermo-stability in the functionalized-nanoparticle-filled vinyl-ester resin nanocomposites as compared with the unmodified-nanoparticle-filled counterparts. The more uniform particle dispersion and the chemical bond betwee…

The interphase finite element

2011

Mesomodelling of structures made of heterogeneous materials requires the introduction of mechanical models which are able to simulate the interactions between the adherents. Among these devices is quite popular the zero thickness interface (ZTI) model where the contact tractions and the displacement discontinuities are the primary static and kinematic variables. In some cases the joint response depends also on the internal stresses and strains within the thin layer adjacent to the joint interfaces. The interphase model, taking into account these additional variables, represents a sort of enhanced ZTI. In this paper a general theoretical formulation of the interphase model is reported and an…

A green method to prepare nanosilica modified graphene oxide to inhibit nanoparticles re-aggregation during melt processing

2017

Abstract A graphene oxide-silica nanohybrid (GOS), self-assembled into a lasagna -like structure, was prepared in water and used as a filler for the melt preparation of polyamide 6 (PA6)-based nanocomposites. For sake of comparison, PA6-based materials were prepared under the same processing conditions by adding GO only or a physical mixture of GO and silica (GO+S). All the materials were characterized from a morphological, spectroscopic, thermal, dynamic-mechanical (DMA) and mechanical point of view. For all the nanocomposites, the interphase was studied either by analyzing loss factor plots coming from DMA measurements and by implementing a novel approach, i.e. combining solvent extractio…

Finite elements with embedded interphases for strain localization in quasi-brittle materials

2023

The paper presents a continuous-discontinuous numerical strategy for sim- ulating localized failure in structures made of quasi-brittle materials using finite elements. The strategy is based on observing acting stresses scenarios, when a diffuse degradation is followed by high deformation bands localizing in certain regions of the structure. The numerical strategy should encom- pass both situations in accordance with the material’s constitutive model. This objective is achieved by introducing a thin layer into a finite element at a certain level of the deformation process. In this study, the thin layer is modeled for the first time by an interphase mechanical device whose consti- tutive beh…

Finite elements augmented with embedded interphases for application in quasi-brittle materials

2022

Quasi-brittle materials mainly fail under shear or tensile stress state. When the stress limit is reached, fractures propagate and the stress-strain relation exhibits a softening branch until failure. In the framework of finite elements, discrete crack models and continuous smeared crack models have been implemented to best capture material’s response. In this ambit, we propose a strategy based on the Augmented Finite Element Method (A-FEM, [1]), which can be placed among the discrete crack models, since intra-element weak discontinuity is considered and modelled through a zero-thickness interphase model (IPH, [2, 3]). The original element is in practice divided in two elastic sub-elements …