Field-theoretical approach to particle oscillations in absorbing matter

The $ab$ oscillations in absorbing matter are considered. The standard model based on optical potential does not describe the total $ab$ transition probability as well as the channel corresponding to absorption of the $b$-particle. We calculate directly the off-diagonal matrix element in the framework of field-theoretical approach. Contrary to one-particle model, the final state absorption does not tend to suppress the channels mentioned above or, similarly, calculation with hermitian Hamiltonian leads to increase the corresponding values. The model reproduces all the results on the particle oscillations, however it is oriented to the description of the above-mentioned channels. Also we touch on the problem of infrared singularities. The approach under study is infrared-free.Comment: 27 pages, 8 figure

Lignin matrix composites from natural resources - ARBOFORMR®

Intensive efforts by research institutions and industry has been unable to generate high added value to a byproduct of the pulp and paper industry, the natural polymer lignin. Chemical pulp mills accumulate approximately more than 50 × 106 tons of it in mass every year, worldwide. A group of researchers and developers, however, developed a family of composites called ARBOFORM®, the polymer lignin being the main component of this new class of engineering materials fully based on renewable raw materials. It is applicable to equipment parts in industry and its properties enable it to be partially substituted for plastics and processed wood. Although it shows woodlike properties, standard polymer engineering technologies can process the material like a thermoplastic material. ARBOFORM can be used for various industrial products, using injection moulding, extrusion and compression moulding. Processing of the material occurs at lower temperatures than is used for synthetic thermoplastics and it does not need compounding, which saves substantial energy and cycle time. The resulting parts show a lower shrinkage than those made from synthetic plastics, reveal excellent acoustic properties and enable straightforward recycling. Continued research and development upgraded the material, giving it advanced properties. As expected from engineering plastics, these comprise high stiffness and impact strength, surface smoothness, various functionalities like flame retardancy, thermal and electrical conductivity, various colours and the absence of processing agents. In particular, advanced bio-inspired materials can be derived by pyrolysis, which maintains shape at smaller dimensions. Selected examples provide an overview of various applications for mass consumer and industrial goods, developed earlier currently under detailed investigation

Verbundprofil, insbesondere fuer Fensterrahmen

DE 19852082 C UPAB: 20000725 NOVELTY - An extruded hollow section of synthetic polymer (3) is reinforced by an inner section (2) of extrudable lignin. The lignin is preferably an alkali lignin and contains synthetic or natural reinforcing fibers. A decorative covering layer (5), e.g. a wood veneer, can be applied. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for the manufacturing process using co-extrusion from a two-part extruder (8,9) through a common die (10). USE - Composite extruded hollow section, especially for window frames. ADVANTAGE - Replacing aluminum reinforcement with lignin is cost-effective, gives better thermal insulation and allows easier recycling