From carbon nanotube coatings to high‐performance polymer nanocomposites

Since their discovery at the beginning of the 1990s, carbon nanotubes (CNTs) have been the focus of considerable research by both academia and industry due to their remarkable and unique electronic and mechanical properties. Among numerous potential applications of CNTs, their use as reinforcing materials for polymers has recently received considerable attention since their exceptional mechanical properties, combined with their low density, offer tremendous opportunities for the development of fundamentally new material systems. However, the key challenge remains to reach a high level of nanoparticle dissociation (i.e. to break down the cohesion of aggregated CNTs) as well as a fine dispersion upon melt blending within the selected matrices. Therefore, this contribution aims at reviewing the exceptional efficiency of CNT coating by a thin layer of polymer as obtained by an in situ polymerization process catalysed directly from the nanofiller surface, known as the ‘polymerization‐filling technique’. This process allows for complete destructuring of the native filler aggregates. Interestingly enough, such surface‐coated carbon nanotubes can be added as ‘masterbatch’ in commercial polymeric matrices leading to the production of polymer nanocomposites displaying much better thermomechanical, flame retardant and electrical conductive properties even at very low filler loading. Copyright © 2007 Society of Chemical Industry     

Strain-age Cracking of Alloy 601 Tubes at 600 °C

This case study demonstrates that Alloy 601 (UNS N06601) is susceptible to strain-age cracking. The observation illustrates the potential importance of post weld heat treatment to the successful utilization of this alloy in certain applications.     

FcRn as a Transporter for Nasal Delivery of Biologics: A Systematic Review

FcRn plays a major role in regulating immune homeostasis, but it is also able to transport biologics across cellular barriers. The question of whether FcRn could be an efficient transporter of biologics across the nasal epithelial barrier is of particular interest, as it would allow a less invasive strategy for the administration of biologics in comparison to subcutaneous, intramuscular or intravenous administrations, which are often used in clinical practice. A focused systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. It was registered on the international prospective register of systematic reviews PROSPERO, which helped in identifying articles that met the inclusion criteria. Clinical and preclinical studies involving FcRn and the nasal delivery of biologics were screened, and the risk of bias was assessed across studies using the Oral Health Assessment Tool (OHAT). Among the 12 studies finally included in this systematic review (out of the 758 studies screened), 11 demonstrated efficient transcytosis of biologics through the nasal epithelium. Only three studies evaluated the potential toxicity of biologics’ intranasal delivery, and they all showed that it was safe. This systematic review confirmed that FcRn is expressed in the nasal airway and the olfactory epithelium, and that FcRn may play a role in IgG and/or IgG-derived molecule-transcytosis across the airway epithelium. However, additional research is needed to better characterize the pharmacokinetic and pharmacodynamic properties of biologics after their intranasal delivery.     

Silicon based system in package: Improvement of passive integration process to avoid TBMS failure

Because of its large dimension and its high level of integration, the PICS (Passive Integration Connecting Substrate) developed by NXP prone to top to bottom metal short (TBMS) failure during temperature cycling test. Several options of process modifications as well as new design rules and stress relief patterns for preventing TBMS failure are described. These countermeasures have been evaluated under high thermo-mechanical stress test. The results of these evaluations are also presented in this paper.     

Influence of volume fraction and characteristics of lightweight aggregates on the mechanical properties of concrete

The influence of lightweight expanded clay and shale aggregates on the mechanical performances of concrete is studied through their volume fractions and aggregate qualities. A very thorough characterisation of a series of LWAs is completed. The impact of aggregates is not only related to its particle density but also to the shell thickness, the percentage of large pores and broken grains. A reverse determination of the elastic modulus of LWA is carried out based to the experimental data. The comparison with values measured ultrasonically confirms the part played by the aggregate stiffer shell in mechanical properties of LWA.     

Nanoindentation analysis of the mechanical behavior of Zr-based metallic glasses with Sn, Ta and W additions

Zr₅₇Cu₂₀Al₁₀Ti₈Ni₅ and modified composition by adding Sn, W or Ta are studied using standard mechanical test and nanoindentation. Addition of refractory elements with a Sn micro-addition increases clearly the Young's modulus and the hardness of basic BMG. However, Sn reduces plasticity. Moreover these experiments allowed, in confine plasticity conditions, estimating an apparent activation volume associated to a plastic deformation (≈150 Å³).     

Two-dimensional interaction of oxidic corium with concretes: The VULCANO VB test series

Three two-dimensional Molten Core–Concrete Interaction tests have been conducted in the VULCANO facility with prototypic oxidic corium. The major finding is that for the two tests with silica-rich concrete, the ablation was anisotropic while it was isotropic for limestone-rich concrete. The cause of this behaviour is not yet well understood.Post Test Examinations have indicated that for the silica-rich concrete, the corium melt mixed specifically with mortar, while, for limestone-rich concretes, the analysed samples were in accordance with a corium–concrete mixing. The experimental results are described and compared to numerical codes. Separate Effect Tests with Artificial Concretes and prototypic corium are proposed to understand the phenomena governing the ablation geometry.     

Dielectric Properties of Ba(Zr,Ti)O3-Based Ferroelectrics for Capacitor Applications

The purpose of the present investigation is to describe the influence of the processing parameters on the dielectric behavior of manganese-doped Ba(Ti_{1− x} Zr _x )O₃ceramics, particularly variations in the small-signal aging rate, temperature characteristic, and hysteresis. In this paper, the aging behavior of base-metal electrode materials above the temperature of the permittivity maximum ( T _M), including the influence of the zirconium content and annealing conditions, is described for the first time. The aging rate at temperatures greater than T _M decreases as the oxygen partial pressure increases during annealing and the zirconium content increases, whereas the aging rate exhibits a maximum at temperatures much less than T _M. The behavior is explained in terms of a diffuse phase transition. Hysteresis-loop deformation is observed during aging.     

教皇新堡的葡萄采收之旅

十月的深秋,葡萄采收啦!我来到了位于法国南隆河(Southem Rhone)最著名的葡萄酒产区"教皇新堡(Chateauneuf-du-Pape)",亲历了当地最著名的几家酒庄的葡萄采收。一望无际的葡萄树叶已经开始渐渐退变为红色、黄色,仅剩的绿叶占到了三分之一,远看过去色彩斑斓,让人想起四川著名的风景名胜九寨沟!