Shedding light onto the nano- and micro-structures of B-containing SiOC glasses using high resolution TEM 3D imaging

The internal structure of nanostructured pyrolyzed SiBOC glasses has been analyzed using a combination of transmission electron microscopy techniques including high resolution imaging, EELS spectroscopy and 3D imaging. For the first time, we provide direct information on the 3D architecture within such complex glasses containing SiC nanograins, silica-rich and carbon nanodomains. Their sizes and relative 3D distribution have been precisely quantified. It was shown that the SiC nanocrystals and the silica-rich domains exhibit different types of connectivities with the graphitic carbon network. A direct evidence of the existence of “covalent” bridges between the edges of graphitic nanoplatelets and the SiC nanocrystals is provided. In addition, it was demonstrated that the silica rich domains are not covalently bonded to the graphitic platelets. As a consequence, this amorphous phase can be dissolved into HF and may generate a bimodal porosity, in strong relationship with the initial nanostructure of the SiBOC glass specimen.     

Effect of chemical and biological dipping on acrylamide formation and sensory properties in deep-fried potatoes

The objective of this work was to study the effect of chemical and biological pre-treatments on acrylamide formation in deep-fried potatoes. Prior to deep-frying, potatoes cubes were subjected to lactic acid fermentation in the presence or in the absence of glycine, as well as to immersion in an aqueous solution of the amino acid alone. The effects of each pre-treatment on deep-fried potatoes were compared by evaluating acrylamide formation, browning development as well as sensory attributes and preference. Results showed that deep-fried potatoes subjected to the glycine and fermentation pre-treatments had 35% and 50% less acrylamide content than the water-dipped ones. Lactic acid fermentation in the presence of glycine resulted the most effective in decreasing acrylamide formation up to 70%. Such a pre-treatment did not affect the sensory perceived browning, flavour, sourness and crispness of the deep-fried potatoes. Moreover, according to the results of a pair comparison preference test, no significant differences in preference were found among the samples.     

The effect of humidity, fabric surface geometry and dye type on the colour of cotton fabrics dyed with a select range of anionic dyes

Four C.I. Solubilised Sulphur dyes were applied to cultivated silk fabric using sodium thioglycolate at pH 7, for 30 min at 60 °C in the absence of electrolyte. Medium/deep shades were obtained that displayed good/excellent fastness to washing at 40 °C and little or no sensitivity to oxygen bleach fading. The dry rub fastness of the dyeings ranged from moderate to good whilst the wet rub fastness varied from poor to moderate; light fastness of the 10% omf dyeings varied from low to moderate. The mild application conditions used had little effect on the tensile strength of the fabric.     

Theoretical study of the influence of dispersion factor on dye transport during the dyeing process

During dyeing, dispersive flow is assumed to reduce the concentration gradient of dye liquor flowing through a yarn package, resulting in a more even distribution of dye in the liquor within the package. However, little is known about the degree of significance of dispersive transport, as a proportion of the total transport of dye. This study investigates the influence of dispersion on dye transport during dyeing, based on a finite element method approach utilised in a mathematical model. The model has been applied to establish the influence of several parameters during the course of the dyeing process. This study theoretically discusses the role of dispersion on the rate of dyeing and the uniformity of dye distribution.     

我的建筑观

本文是《伦佐·皮亚诺作品集》(Renzo Piano Logbook)的前言,是反映他本人对自己作品思想的集中论述。古老的职业建筑是一个充满冒险的职业,建筑师总是处于"边界"的一群人,游走于刀锋之上。艺术与科学、创新与记忆、现代与传统,这些分庭抗礼的元素都使得建筑师不得不与危险常伴。他们的工作中充满了各种"材料",我说的不只是混凝土、木头、金属,建筑师要每天打交道的还包括历史、地理、数学以及自然科学、人类学、生态学、美学、技术、气候条件与社会环境。     

Waste gas biofiltration: advances and limitations of current approaches in microbiology

As confidence in gas biofiltration efficacy grows, ever more complex malodorant and toxic molecules are ameliorated. In parallel, for many countries, emission control legislation becomes increasingly stringent to accommodate both public health and climate change imperatives. Effective gas biofiltration in biofilters and biotrickling filters depends on three key bioreactor variables: the support medium; gas molecule solubilization; and the catabolic population. Organic and inorganic support media, singly or in combination, have been employed and their key criteria are considered by critical appraisal of one, char. Catabolic species have included fungal and bacterial monocultures and, to a lesser extent, microbial communities. In the absence of organic support medium (soil, compost, sewage sludge, etc.) inoculum provision, a targeted enrichment and isolation program must be undertaken followed, possibly, by culture efficacy improvement. Microbial community process enhancement can then be gained by comprehensive characterization of the culturable and total populations. For all species, support medium attachment is critical and this is considered prior to filtration optimization by water content, pH, temperature, loadings, and nutrients manipulation. Finally, to negate discharge of fungal spores, and/or archaeal and/or bacterial cells, capture/destruction technologies are required to enable exploitation of the mineralization product CO(2).     

Direct coloration of textiles with photochromic dyes. Part 3: dyeing of wool with photochromic acid dyes

Wool dyed with two isomeric water‐soluble spirooxazine‐based photochromic acid dyes, which were specifically designed and synthesised for direct application to protein and polyamide substrates, showed reversible change from a pale yellowish colour to blue when exposed to sunlight or UV light. With the first dye, significantly higher photochromic colour change was obtained when the wool was bleached, a feature attributed to a more open fibre structure which may facilitate penetration of the non‐planar dye anion and also the photocoloration reaction which requires a change in molecular geometry. Experimentation demonstrated that the optimum conditions for application of this dye to wool was from an aqueous dyebath at neutral pH and a temperature of 60 °C. An investigation using HPLC demonstrated that the dye was susceptible to decomposition in aqueous solution at higher temperatures and at lower pH values. The second dye was also applied to wool fabric to give a fabric with similar photochromic properties. The technical performance of the dyed fabrics, in terms of washfastness and photostability, was assessed.     

Selective Palladium‐Catalyzed Suzuki–Miyaura Reactions of Polyhalogenated Heteroarenes

The palladium‐catalyzed Suzuki–Miyaura reaction of multiply halogenated, electron‐rich and electron‐deficient heteroarenes is one of the most reliable and environmentally friendly tools for installing a wide range of non‐functionalized and functionalized carbon substituents onto heteroaromatic systems with exquisite chemo‐ and site‐selectivity. For substrates with different halogen groups the chemoselectivity of the Suzuki–Miyaura reactions has been found to be dependent on the reactivity difference between the halogens. However, the hardest achievement of selectivity in Suzuki–Miyaura monocouplings involving polyhalogenated heteroarenes with identical halogen atoms has been shown to be dominated by steric and electronic effects and the presence of directing groups at positions neighbouring the reaction sites. Moreover, in the case of symmetrically substituted dihaloheteroarenes with identical halogen atoms, highly selective monocoupling reactions have often been achieved only after a careful optimization of reaction parameters including the catalyst precursor, base, solvent, and the molar ratio between electrophile and organoboron reagent. This critical review with 341 references covers developments on the chemo‐ and site‐selective Suzuki–Miyaura monocoupling reactions of polyhalogenated heteroarenes with different or identical halogen atoms. It also includes the synthesis of polysubstituted heteroarenes, not easily accessible by other means, via consecutive monocoupling reactions and/or a more synthetically valuable approach involving one‐pot polycoupling reactions.     

Radical mediated graft modification of polyolefins: Vinyltriethoxysilane addition dynamics and yields

The dynamics and yields of peroxide‐initiated grafting of vinyltriethoxysilane (VTEOS) to tetradecane and linear low density polyethylene (LLDPE) are described. VTEOS grafting kinetics at 160°C abide by the basic tenets of radical‐mediated additions in terms of the influence of initiator loading and homolysis rate. However, reaction yields recorded for both the model and polymer systems are surprisingly insensitive to temperature, in apparent conflict with conventional models of free radical addition chemistry. These experimental observations are used to identify the predominant reactions within a general kinetic scheme, and to support the assumptions required to develop a rate expression that captures the effect of reagent concentrations on the dynamics of graft‐modification. POLYM. ENG. SCI. 46:1754–1761, 2006. © 2006 Society of Plastics Engineers.     

On the interaction between a fixed bed of solid material and the confining column wall: the Janssen approach

A general verification of the Janssen model was carried out by measuring the bottom pressure of different granular materials confined in a cylindrical column. Special effort was made in order to experimentally test all the physical parameters appearing in Janssen’s equation, especially the particle-wall friction coefficient μ and Janssen’s factor, K. The results indicate that although Janssen’s approach is capable of qualitatively reproduce the observed behavior, the physical meaning of the parameter appearing in Janssen’s equation requires further considerations.