On Modulus and Fracture Toughness of Rigid Particulate Filled High Density Polyethylene

A Kaolin-filled, high-density polyethylene (HDPE) system was used to illustrate the influence of particulates on modulus and toughness of the bulk material. A variation of filler content, particulate size and coupling quality for two HDPE-matrix systems with different viscosity led to a strong dependency of elastic modulus and fracture toughness under various testing conditions, e.g. static loading, fatigue and impact.

A stiffness improvement with increasing filler content was achieved by all coupling qualities. The developed Kaolin reinforcement of HDPE with optimised coupling offers an improvement of the stiffness and toughness under all investigated loading conditions. The degree of improvement depends on the particulate size and matrix viscosity. The energy dissipation mechanisms were investigated by fractographic analysis.     

Einsatz von Enzymen und Antikörpern in organischen Lösungsmitteln

Application of Enzymes and Antibodies in Organic Solvents . This review outlines the influence of organic solvents on antibodies, enzymes and their reactions, the different kinds of enzyme-solvent systems, the various advantages of organic solvents compared with water and how they can be used for synthetic and analytical purposes. Main applications are the enzymatic synthesis of optically pure organic chemicals used as drugs, research chemicals, dyes or fragrants, as well as the analysis of hydrophobic compounds. Examples can be given of bioconversions in organic media by microbial cells and of syntheses with catalytic antibodies. Moreover, the full biotechnological potential of chemically or genetically engineered enzymes can only be exploited if the diversity of possible media is taken into account.     

On the incremental growth and shrinkage of LR goto-graphs

The LR(0) goto-graph is the basis for the construction of parsers for several interesting grammar classes such as LALR and GLR. Early work has shown that even when a grammar is an extension to another, the goto-graph of the first is not necessarily a subgraph of the second. Some authors presented algorithms to grow and shrink these graphs incrementally, but the formal proof of the existence of a particular relation between a given goto-graph and a grown or shrunk counterpart seems to be still missing in literature as of today. In this paper we use the recursive projection of paths of limited length to prove the existence of one such relation, when the sets of productions are in a subset relation. We also use this relation to present two algorithms (Grow and Shrink) that transform the goto-graph of a given grammar into the goto-graph of an extension or a restriction to that grammar. We implemented these algorithms in a dynamically updatable LALR parser generator called DEXTER (the Dynamically EXTEnsible Recognizer) that we are now shipping with our current implementation of the Neverlang framework for programming language development.     

Fat-simulating and accelerating solvents for polyolefins and MWD of solvent extracts of polyethylenes

Migration kinetics of straight-chain oligomers and antioxidants from several polyolefins at different temperatures into various solvents have been studied by radioactive tracer techniques. Anhydrous ethanol appears to be a well suited food-oil or liquid-fat simulant for extracting different types of migrants from polyolefins. Pure and mixed triglycerides are also good oil or fat simulants, but the triglycerides offer no simpler analytical procedures than the use of oil or fat themselves. n-Octanol may also be considered as a reasonable oil or fat simulant; however, its action depends somewhat on the choice of migrants. The accelerating action of n-heptane over that of oil or simulants is quantitatively demonstrated. The accelerating effects are greater for migration systems with lower diffusion coefficients. The diffusion coefficients for migration into n-heptane are about 20 times greater than the diffusion coefficients into ethanol or oil for otherwise identical migration systems yielding diffusion coefficients of about 10^?7 cm²s^?1 into oil or ethanol. For systems yielding diffusion coefficients into oil or ethanol of about 10^?12 cm²s^?1, the corresponding diffusion coefficients into n-heptane are about 1000 times greater. The molecular weight distributions (MWDs) of the n-heptane and ethanol extracts of polyolefins have been analysed. n-Heptane can not only accelerate the migration of the individual migrant but also remove oligomer species that are slightly soluble or present at low levels in the oil or simulant extracts.     

BiOSS: A system for biomedical ontology selection

In biomedical informatics, ontologies are considered a key technology for annotating, retrieving and sharing the huge volume of publicly available data. Due to the increasing amount, complexity and variety of existing biomedical ontologies, choosing the ones to be used in a semantic annotation problem or to design a specific application is a difficult task. As a consequence, the design of approaches and tools addressed to facilitate the selection of biomedical ontologies is becoming a priority. In this paper we present BiOSS, a novel system for the selection of biomedical ontologies. BiOSS evaluates the adequacy of an ontology to a given domain according to three different criteria: (1) the extent to which the ontology covers the domain; (2) the semantic richness of the ontology in the domain; (3) the popularity of the ontology in the biomedical community. BiOSS has been applied to 5 representative problems of ontology selection. It also has been compared to existing methods and tools. Results are promising and show the usefulness of BiOSS to solve real-world ontology selection problems. BiOSS is openly available both as a web tool and a web service.     

2-Layer Right Angle Crossing Drawings

A 2-layer drawing represents a bipartite graph where each vertex is a point on one of two parallel lines, no two vertices on the same line are adjacent, and the edges are straight-line segments. In this paper we study 2-layer drawings where any two crossing edges meet at right angle. We characterize the graphs that admit this type of drawing, provide linear-time testing and embedding algorithms, and present a polynomial-time crossing minimization technique. Also, for a given graph G and a constant k, we prove that it is $\mathcal{NP}$ -complete to decide whether G contains a subgraph of at least k edges having a 2-layer drawing with right angle crossings.     

FMAP: Distributed cooperative multi-agent planning

This paper proposes FMAP (Forward Multi-Agent Planning), a fully-distributed multi-agent planning method that integrates planning and coordination. Although FMAP is specifically aimed at solving problems that require cooperation among agents, the flexibility of the domain-independent planning model allows FMAP to tackle multi-agent planning tasks of any type. In FMAP, agents jointly explore the plan space by building up refinement plans through a complete and flexible forward-chaining partial-order planner. The search is guided by h _{D T G} , a novel heuristic function that is based on the concepts of Domain Transition Graph and frontier state and is optimized to evaluate plans in distributed environments. Agents in FMAP apply an advanced privacy model that allows them to adequately keep private information while communicating only the data of the refinement plans that is relevant to each of the participating agents. Experimental results show that FMAP is a general-purpose approach that efficiently solves tightly-coupled domains that have specialized agents and cooperative goals as well as loosely-coupled problems. Specifically, the empirical evaluation shows that FMAP outperforms current MAP systems at solving complex planning tasks that are adapted from the International Planning Competition benchmarks.     

Durability of Adhesion Between Metals and Polymers

Adequate adhesion between metals and polymers is primarily the result of chemical bonds in the boundary layer. This region, however, is subject to degradation by moisture. Three modes of deterioration are observed. The first is a largely reversible weakening effect in the polymer layer near the metal oxide surface. The structure of this layer differs from that of the bulk and is influenced by the chemical and physical properties of the surface. The second is a slow transformation of the oxide by hydration and a diffusion of oxide constituents into the polymer. This process is irreversible and is influenced by the state of the surface and chemical properties of the polymer. The third is a fast deterioration of the oxide by primary corrosion usually initiating at an unprotected edge but occasionally arising within the body of a joint.     

Chemische Methoden der Abwasser-Aufbereitung

Chemical methods of waste-water treatment. Chemical methods of waste management by oxidation can be considered for particular effluents whose constituents are degraded too slowly in conventional sewage treatment plants or which interfere with the biodegradation of other substances. Of these methods, those we have to choose from today are, in order of increasing operating temperature: oxidation with hydrogen peroxide – wet oxidation at high pressure – evaporation and combustion. None of these methods is fundamentally better than the others, i.e. none has a maximum ecological benefit coinciding with a minimum economic impact. Detailed experimental work is required to establish the limits and possibilities in each case and thus to form a basis for useful comparisons. Thermal processes are normally ruled out for low concentrations of degradable constituents in waste water because the specific energy costs per unit volume are too high; this is where hydrogen peroxide may offer advantages, especially when the proportion of these constituents fluctuates. With higher concentrations, wet oxidation can be employed; evaporation and combustion are suitable if there is also a high concentration of inorganic salts.