Unravelling the consequences of ultra-fine milling on physical and chemical characteristics of flax fibres

In recent years, lignocellulosic biomass has been increasingly used in various applications, often replacing petro-sourced materials. While for many of these applications the plant materials require coarse milling, some new applications for green chemistry, bio-energy and bio-packaging necessitate comminution to obtain very finely calibrated particles (below 200 m in size). This milling step is not inconsequential for lignocellulosic materials and can influence the physical (size, shape) and chemical characteristics (cellulose crystallinity, composition) of the powder. However, these different effects are still poorly understood. In this work, we study and elucidate the impact of intense and ultra-fine milling on the physico-chemical properties of plant fibres. Flax was chosen for this study because of its well-described hierarchical structure and biochemical composition in literature, making it a model material. Our main results evidence a strong impact of 0 to 23hrs ball milling on flax fibre morphology, especially on fibre aspect ratio falling from 20 to 5 but also on cell wall ultrastructure and composition. Cellulose content and crystallinity significantly decrease with milling time, leading to higher water sorption and lower thermal stability.The authors also thank the French national research Network ‘GDR 3710 INRA/ CNRS SYMBIOSE – Synthons et matériaux biosourcés’, for its financial suppor

Supply driven mortgage choice

Variable mortgage contracts dominate the UK mortgage market (Miles, 2004). The dominance of the variable rate mortgage contracts has important consequences for the transmission mechanism of monetary policy decisions and systemic risks (Khandani et al., 2012; Fuster and Vickery, 2013). This raises an obvious concern that a mortgage market such as that in the UK, where the major proportion of mortgage debt is either at a variable or fixed for less than two years rate (Badarinza, et al., 2013; CML, 2012), is vulnerable to alterations in the interest rate regime. Theoretically, mortgage choice is determined by demand and supply factors. So far, most of the existing literature has focused on the demand side perspective, and what is limited is consideration of supply side factors in empirical investigation on mortgage choice decisions. This paper uniquely explores whether supply side factors may partially explain observed/ex-post mortgage type decisions. Empirical results detect that lenders’ profit motives and mortgage funding/pricing issues may have assisted in preferences toward variable rate contracts. Securitisation is found to positively impact upon gross mortgage lending volumes while negatively impacting upon the share of variable lending flows. This shows that an increase in securitisation not only improves liquidity in the supply of mortgage funds, but also has the potential to shift mortgage choices toward fixed mortgage debt. The policy implications may involve a number of measures, including reconsideration of the capital requirements for the fixed, as opposed to the variable rate mortgage debt, growing securitisation and optimisation of the mortgage pricing policies

Elucidation on the Effect of Operating Temperature to the Transport Properties of Polymeric Membrane Using Molecular Simulation Tool

Existing reports of gas transport properties within polymeric membrane as a direct consequence of operating temperature are in a small number and have arrived in diverging conclusion. The scarcity has been associated to challenges in fabricating defect free membranes and empirical investigations of gas permeation performance at the laboratory scale that are often time consuming and costly. Molecular simulation has been proposed as a feasible alternative of experimentally studied materials to provide insights into gas transport characteristic. Hence, a sequence of molecular modelling procedures has been proposed to simulate polymeric membranes at varying operating temperatures in order to elucidate its effect to gas transport behaviour. The simulation model has been validated with experimental data through satisfactory agreement. Solubility has shown a decrement in value when increased in temperature (an average factor of 1.78), while the opposite has been observed for gas diffusivity (an average factor of 1.32) when the temperature is increased from 298.15Â K to 323.15Â K. In addition, it is found that permeability decreases by 1.36 times as the temperature is increased

Ectopic callose deposition into woody biomass modulates the nano-architecture of macrofibrils

Plant biomass plays an increasingly important role in the circular bioeconomy, replacing non-renewable fossil resources. Genetic engineering of this lignocellulosic biomass could benefit biorefinery transformation chains by lowering economic and technological barriers to industrial processing. However, previous efforts have mostly targeted the major constituents of woody biomass: cellulose, hemicellulose and lignin. Here we report the engineering of wood structure through the introduction of callose, a polysaccharide novel to most secondary cell walls. Our multiscale analysis of genetically engineered poplar trees shows that callose deposition modulates cell wall porosity, water and lignin contents and increases the lignin–cellulose distance, ultimately resulting in substantially decreased biomass recalcitrance. We provide a model of the wood cell wall nano-architecture engineered to accommodate the hydrated callose inclusions. Ectopic polymer introduction into biomass manifests in new physico-chemical properties and offers new avenues when considering lignocellulose engineering

Distillation simulée par chromatographie en phase gazeuse sur des coupes lourdes de pétrole

Ce travail est le fruit d'une action concertée entre Institut Français du Pétrole (IFP), Compagnie Française de Raffinage (CFR) et Société Nationale Elf Aquitaine (Production) (SNEA (P)) au sein du GEC (Groupe d'Etudes Concertées) sur l'analyse des fractions lourdes du pétrole. On décrit dans cette étude une méthode de chromatographie gazeuse permettant de caractériser par une courbe de distillation simulée, des coupes lourdes 370-535 °C, obtenues par distillation sous vide des résidus atmosphériques. Un mode opératoire détaillé est fourni, contenant des indications précises sur la préparation des colonnes, leur conditionnement, leurs conditions optimales d'emploi et sur les précautions d'exploitation quantitative des chromatogrammes obtenus. Des essais de répétabilité et de reproductibilité ont été réalisés sur différentes coupes de produits lourds. La qualité des résultats obtenus a conduit à une tentative de normalisation de la méthode au sein du Bureau de Normalisation du Pétrole