Search results for "Composite"

Dry content analysis in wet pressing: Sensitivity to pressing variables

2002

Optimal manufacturing and mechanical characterization of high performance biocomposites reinforced by sisal fibers

2018

Abstract The increasing interest about eco-sustainable materials in the industrial production (automotive, civil construction, packaging), has led to the increase of the research works dealing with biocomposites. However, until now the most attention has been devoted to the development of short fiber biocomposites for non-structural applications, whereas only a few works have considered high performance biocomposites for structural applications. Consequently, the development of structural biocomposites from robust natural fibers, as sisal fibers, is a result expected from the scientific community, but not yet achieved. In order to give a contribution to the implementation of high performanc…

Chemical compatibility of bulk alumina in flowing PbLi alloy under magnetic field

2021

Abstract Electrically insulating flow channel inserts (FCI) may be needed in liquid-based breeding blanket concepts to electrically decouple the metal flow from the strong magnetic field in a future fusion reactor. Although the magnetohydrodynamic simulation demonstrates a reduction of the pressure drop when a sandwich-like steel-alumina-steel FCI is employed, the tritium production efficiency in the breeding zone of a breeding blanket is limited to 550 °C due to the steel corrosion. Previous theoretical thermomechanical analyses point out the possible occurrence of induced interfacial stresses between the steel and the ceramic part. Both factors motivate the actual FCI development towards …

18O-labeled interstitial oxygen molecules as probes to study reactions involving oxygen-related species in amorphous SiO2

2012

Abstract Isotope labeling has been widely used to study reactions involving oxygen species in amorphous SiO 2 ( a -SiO 2 ). This article briefly describes recent progress in 18 O labeling techniques to study reactions involving interstitial oxygen molecules (O 2 ), which is one of the most important excess oxygen species in a -SiO 2 . The primary focus will be on the combination of the 18 O labeling with photoluminescence spectroscopy, which enables sensitive and selective detection of interstitial O 2 . Advantages of this method and results of evaluation of oxygen exchange between interstitial O 2 and the Si―O network of a -SiO 2 will be presented.

Solvent free oxidation of primary alcohols and diols using thymine iron(III) catalyst.

2010

In this study, we developed an efficient and selective iron-based catalyst system for the synthesis of ketones from secondary alcohols and carboxylic acids from primary alcohol. In situ generated iron catalyst of thymine-1-acetate (THA) and FeCl(3) under solvent-free condition exhibits high activity. As an example, 1-octanol and 2-octanol were oxidized to 1-octanoic acid and 2-octanone with 89% and 98% yields respectively.

Inhibition Probing on a Cut-Edge Electrode Machined from a Primer-Coated 2024-T3 Alloy

2013

Conventional corrosion protection of 2024-T3 alloys (AA2024T3) in aeronautic structures combines conversion coating with chromate-inhibited primer protected by a top-coat. In some cases this protection can break down after mechanical damage to the paint systems inducing a risk of localized corrosion if the release of inhibitors trapped in the primer does not reach a critical level. There is a need for developing computational models combining the inhibitor release and transport within and from the coating system andthecorrosioninhibitionprocess,toassistinthedesignofnewmultifunctionalcoatingsystems.Theinfluenceonthecorrosioninhibition of various parameters such inhibitor release rate, defect…

Effect of active application of self-etching ceramic primer on the long-term bond strength of different dental CAD/CAM materials

2021

Made available in DSpace on 2022-04-29T08:36:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Background: The objective of this in vitro study was to evaluate the effect of the active application of self-etching ceramic primer (ME&P) on the bond strength of different dental CAD/CAM materials (Lithium Disilicate ceramic (LD), Leucite ceramic (LE), Zirconia reinforced lithium silicate ceramic (ZLS), and Hybrid ceramic (HC)) with thermocycling aging. Material and Methods: The samples were randomly divided into 16 groups (n = 20). Dual resin cement cylinders were made and light cured for 10 s (1.200 mW/cm2) for the shear bond strength test. 3-way ANOVA revealed that the factors w…

Comparison between different surface treatment methods on shear bond strength of zirconia (in vitro study)

2020

Background To compare the effect of Er:YAG Laser and Air particle abrasion (APA) surface treatments on shear bond strength of Y-TZP to composite resin cuboids in the presence and absence of primer application and salivary contamination. Material and methods Seventy-two cuboidal shaped specimens 7x7x3 were prepared from Y-TZP using CADCAM, cleaned and sintered. Specimens were divided into 2 main groups (n=36) according to surface treatment method; Air particle abrasion (A) and laser (L). Each group was subdivided into 2 subgroups (N = 18) according to surface modification using primer; each subgroup was further divided into 2 subdivisions (N=9) according to the presence of salivary contamina…

An evaluation of the environmental factors for supply chain strategy decisions using grey systems and composite indicators

2020

[EN] The purpose of this work is to assess the importance of environmental factors in a supply chain with four partners as a preliminary step to select the competitive strategies and objectives. To achieve this purpose, a real case study was carried out in a footwear supply chain, in which two approaches were used: the grey system theory and uncertainty analysis tools for composite indicators. In order to validate both approaches, a seven-phase research methodology was developed and applied to our case study. In addition, the priorization of environmental factors was calculated individually for each partner. The results allow managers to establish the competitive strategy that best suits th…

Silver nanoparticles stabilized by a polyaminocyclodextrin as catalysts for the reduction of nitroaromatic compounds

2015

Abstract Silver nanoparticles stabilized by means of poly -(6- N , N -dimethyl-propylenediamino)-(6-deoxy)-β-cyclodextrin were synthesized, characterized by different techniques (UV–vis spectroscopy, Dynamic Light Scattering, High Resolution Transmission Electron Microscopy, Fourier-transform IR Spectroscopy) and used as catalysts for the reduction of various nitrobenzene derivatives with sodium borohydride. The nanocomposites obtained appear to have an organized structure, with a metal core surrounded by a layer-structured coating shell. Kinetic data, rationalized in terms of a modified Langmuir–Hinshelwood model, evidenced a non-linear dependence of the reaction rate on the concentration …