Environmentally-compatible alkyd paints stabilized by wood hemicelluloses

Wood biorefining currently involves large-scale industrial processes where a notable portion of raw materials, namely hemicelluloses and lignin, are either lost with the process water, degraded, or burnt for energy. Value added utilization of polymeric hemicelluloses is challenging due to their intermediate molar mass and the presence of other wood components, such as phenolic residues or wood extractives. Oil-in-water (O/W) emulsions represent a diverse and abundant class of applications in which the natural properties of wood hemicelluloses are beneficial. In the current work, we present highly promising new technical alkyd paint emulsion systems stabilized with hardwood glucuronoxylans (GX) and softwood galactoglucomannans (GGM). Samples from three isolation methods and their further fractionation by ethanol precipitation were systematically compared with regard to hemicellulose composition, interfacial activity, and functionality in emulsions. Emulsification of alkyd resins was successful with both GX and GGM obtained by various biorefining strategies. The highest emulsion stability over storage was achieved using crude non-purified GX and GGM fractions, and was correlated with the presence of phenolic compounds and extractives, interfacial activity, and small droplet size. Hardwood GX and softwood GGM are envisioned as natural emulsifiers of alkyd O/W emulsions, which are examples of diverse and abundantly-used technical dispersions. This study can be utilized as a guideline for targeted extraction of hemicelluloses with desired functionality, and as a protocol for developing environmentally-compatible industrial dispersions.Peer reviewe

Structural sketcher: a tool for supporting architects in early stages

Traditionally, architects use pen and paper for the early stages. Architects have great expertise in drawing, their use is simple and has low overhead, and a high precision is not required, and even counterproductive. The last decades many systems to support architects have been developed. These are primarily suited for the production of final technical drawings. Architects do not use them in the early phases, because they do not offer the freedom, speed, and ambiguity needed there. Nevertheless, the use of a computer could offer benefits, such as ease of modification and editing as well as higher level support. The aim of the project described in this thesis was to develop a computer-sketching tool to support architects in the early design stages

Non-cellulosic heteropolysaccharides from sugarcane bagasse - Sequential extraction with pressurized hot water and alkaline peroxide at different temperatures

The xylan-rich hemicellulose components of sugarcane bagasse were sequentially extracted with pressurized hot-water extraction (PHWE) and alkaline peroxide. The hemicelluloses were found to contain mainly arabinoxylans with varying substitutions confirmed by different chemical and spectroscopic methods. The arabinoxylans obtained from PHWE were found to be more branched compared to those obtained after alkaline extraction. Sequential extraction could be useful for the isolation of hemicelluloses with different degree of branching, molar mass, and functional groups from sugarcane bagasse, which can be of high potential use for various industrial applications

Structural Sketcher: Representing and applying well-structured graphic representations in early design

Computational drawing support has the potential to improve design support in the early phase. Much work in this area is devoted to input of design information, manipulation, and presentation. Based on a review of current work, we note that among other things, digital drawing tools should be close to the conventions and techniques already used by architects. This is, in principle, possible by processing strokes in a more or less traditional sketch approach, or by offering specialised commands that provide a direct implementation of such conventions. The latter approach is covered by Structural Sketcher. A subset of drawing conventions developed earlier, called graphic units, is adopted within the system. In order to contribute to design support, the application of such graphic units should be fast and intuitive, and the definition of internal relationships should be quick and straightforward. For intuitive manipulation, Structural Sketcher incorporates the “paper and scissorsi metaphor, and introduces a novel UI-concept called the KITE. To achieve an easy and fast maintenance of relationships, a graph based on anchor-points is built-up on the fly. Performance of the system has been tested on a quantitative and qualitative basis. The system shows the benefit that graphic units can bring to drawing support, and how these can be implemented. To conclude, limitations and further work are discussed