Entwicklung eines hybriden Genetischen Algorithmus zur Tourenplanung

Subject of this paper is the development of a Genetic Algorithm (GA) for the Vehicle Routing Problem (VRP). At first a simple GA for the one-depot “standard” VRP with travel distance and capacity restrictions is presented. Then the GA is enhanced by hybridization. The performance of the enhanced GA is evaluated. Finally, the GA is modified to handle a cost function and some real world restrictions.     

Partitioning and Localization of Fragrances in Surfactant Mixed Micelles

The localization and dynamics of fragrance compounds in surfactant micelles are studied systematically in dependence on the hydrophobicity and chemical structure of the molecules. A broad range of fragrance molecules varying in octanol/water partition coefficients P _ow is employed as probe molecules in an aqueous micellar solution, containing anionic and nonionic surfactants. Diffusion coefficients of surfactants and fragrances obtained by Pulsed Field Gradient (PFG)-NMR yield the micelle/water distribution equilibrium. Three distinct regions along the log(P _ow) axis are identified: hydrophilic fragrances (log(P _ow) < 2) distribute almost equally between micellar and aqueous phases whereas hydrophobic fragrances (log(P _ow) > 3.5) are fully solubilized in the micelles. A steep increase of the incorporated fraction occurs in the intermediate log(P _ow) region. Here, distinct micelle swelling is found, while the incorporation of very hydrophobic fragrances does not lead to swelling. The chemical structure of the probe molecules, in addition to hydrophobicity, influences fragrance partitioning and micelle swelling. Structural criteria causing a decrease of the aggregate curvature (flattening) are identified. ²H-NMR spin relaxation experiments of selectively deuterated fragrances are performed monitoring local mobility of fragrance and leading to conclusions about their incorporation into either micellar interface or micelle core. The tendencies of different fragrance molecules (i) to cause interfacial incorporation, (ii) to lead to a flattening of the micellar curvature and (iii) to incorporate into micelles are shown to be correlated.     

Understanding the role of iron chlorides in the de novo synthesis of polychlorinated dibenzo-p-dioxins/dibenzofurans

The formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) was investigated for mixtures of carbon black and iron chloride supported on a ceramic glass powder matrix in a low (2%) oxygen environment. Three iron chloride types (iron(II) chloride tetrahydrate, iron(III) chloride hexahydrate, and iron(II) oxychloride) were studied to gain some insights into their role in de novo formation. The importance of iron(II) and iron(III) chlorides both as chlorinating agents and promoters of low-temperature carbon gasification was observed. Iron(III) oxychloride was shown to be a very effective promoter at 325 degrees C and above; its conversion to iron(III) chloride was suggested as a key step. The predominant product was octachlorodibenzofuran. The oxide support matrix was found to be an important parameter.     

Anisotropic Transferred Hyperfine Interaction in a Heavy-Fermion Compound: Paramagnetic NMR Line Shift in a CeCu6 Single Crystal

We report on single crystal nuclear magnetic resonance spectroscopy for ⁶³Cu at the Cu(5) sites in the heavy-fermion paramagnet CeCu₆ for constant external magnetic field strength (7 T) applied along the “hardest” magnetic direction b and varied temperature (5 − 100 K). The transferred field coupling constant α _b (5) = + 3.40(31) kOe/μ _B is derived from the van Vleck like paramagnetic line shift. These results establish the predominance of anisotropic spin and orbital polarization acting on the Cu sites neighbouring the Ce 4f local moment. Because magnetically induced electric quadrupolar interaction at this Cu site is not unusually enhanced, we conclude that the exchange polarization mechanism at the Ce site is the source of the observed anisotropy. Impact of the substitution of Cu(2) by Au on the Ce³⁺ single-ion ground state properties and magnetic characteristics of CeCu_6-x Au _x is discussed.      

The Language Evolver Lever — Tool Demonstration —

Since many domains are constantly evolving, the associated domain specific languages (DSL) inevitably have to evolve too, to retain their value. But the evolution of a DSL can be very expensive, since existing words of the language (i.e. programs) and tools have to be adapted according to the changes of the DSL itself. In such cases, these costs seriously limit the adoption of DSLs.This paper presents Lever, a tool for the evolutionary development of DSLs. Lever aims at making evolutionary changes to a DSL much cheaper by automating the adaptation of the DSL parser as well as existing words and providing additional support for the correct adaptation of existing tools (e.g. program generators). This way, Lever simplifies DSL maintenance and paves the ground for bottom-up DSL development.