Papers by Keyword: Product Properties

Abstract: The torrefaction of rice husk was performed in a laboratory-scale torrefaction reactor at different temperatures (200, 230, 260, and 290 °C) for 30 min. It was found that the decomposition of hemicellulose was the direct reason for changes in the fuel properties of solid products after torrefaction. As the torrefaction temperature rose from 200 °C to 290 °C, the yield of torrefied rice husk decreased gradually from 97.47% to 67.03%, whereas the yields of liquid and noncondensable gas products increased from 2.01% to 15.67% and from 0.52% to 17.30%, respectively. Liquid products contained water and a small amount of acetic acids. CO₂ and CO were the main gas products of rice husk torrefaction.

Abstract: The last decade has shown an expanding interest towards incremental sheet forming (ISF). The present paper focuses on a wide variety of materials used in ISF with emphasis on material behavior and post forming properties. Material behavior knowledge is essential for improving process control and accuracy, post forming properties are essential for introducing ISF for wider industrial use. Included in the study are: a ferritic and four austenitic stainless steel grades, a deep drawing steel, as well as copper and silver. The two latter materials have been widely used for crafted products trough centuries and still have their place in high-end products. The suitability of the different materials for ISF is studied and compared. A comprehensive testing procedure is performed to gain information about behavior during and properties after deformation. The material property evolution is also compared to other forming methods to further enhance understanding of the process. The materials can be divided into stable and metastable materials. Stainless steels are an increasingly important class of alloys that are widely used in industry today. The structure of austenitic stainless steels is metastable which may lead to phase transformation. Strain induced martensite phases can form during plastic deformation of these steels. The formation of martensite affects significantly their mechanical behavior by enhancing the work hardening. Transformation impedes the property prediction as it is linked to the process conditions which may vary during forming. The stable materials lack phase transformation but show both diverse and similar material property evolution as a result of ISF.

Abstract: New experimental methods for investigations of phase formation during SHS have been established. First experiments using penetrating synchrotron radiation and energy dispersive detectors for different classes of complex inorganic materials were carried out at ESRF (Grenoble, France) and Daresbury (UK). A new and very sensitive thermal imaging method (Thermal Imaging Technique (TIT)) based on continuous registration of the whole combustion process by using highly sensitive IR-camera and software developed by MIKRON Instruments Co. (USA) was used for precise registration of the combustion parameters. SHS was performed on different types of pure and doped complex inorganic materials in pellet and powder form in a range of dc magnetic fields up to 20 T and in electrical field strengths up to ±220 kV/m. The dc magnetic field was applied during the reaction, supplied either by a permanent magnet (transverse, up to 1.1 T) or by an electromagnet (longitudinal, up to 20 T). The dc electrical field was applied along the direction of the combustion wave front propagation. The combined processes of SHS and SLS (Selective Laser Sintering) of 3D articles for different powdered compositions were optimized with laser irradiation power.