Numerical homogenization of heterogeneous and cellular materials utilizing the finite cell method

We present a new approach for the numerical homogenization of cellular and heterogeneous materials. The procedure is based on the finite cell method, which is applied to efficiently discretize representative volume elements for which effective material properties are computed. The starting point for our homogenization might be either a computer-aided design of a heterogeneous material or a three-dimensional computer tomography (CT-scan) of the specimen of interest. A fully automatic discretization in terms of finite cells, applying a hierarchic extension process to control the discretization error, is utilized to solve the corresponding boundary value problems arising during the homogenization. Special emphasis is placed on the numerical treatment of boundary conditions. To this end we apply the window method, which can be interpreted as a variant of the self-consistency method. Several numerical examples ranging from porous materials to fiber-reinforced composites will be presented, demonstrating the efficiency of our approach. The homogenization procedure will be also applied to a foam, a CT-scan of which is available.     

Systematisierung des Nutzens von ERP-Systemen in der Fertigungsindustrie

This paper classifies and explores the benefits of Enterprise Resource Planning (ERP) systems using the individual manufacturing facility as the level of analysis. We focused on German companies using SAP R/3. Two successful cases are described in detail. The cases revealed that remarkable benefits have been realized in the following categories: ?Process efficiency (business processes)”, ?Market efficiency (market and customer orientation)”, ?Resource efficiency (productivity and profitability)”, and ?Delegation efficiency (gathering of information)”. Data standardization and integration explain many of these benefits. However, the users complain about higher workloads as a result of the complexity and required data structures of these systems. Therefore, they show lower acceptance for the new system.     

DInSAR investigation in the Pärvie end-glacial fault region,Lapland, Sweden

Northern Fennoscandia bears witness to the Pleistocene glaciation in the form of a series of large faults that have been shown to have ruptured immediately after the retreat of the ice sheet, about 9500 years ago. The largest one, known as the Pärvie fault, consists of a 155 km long linear series of fault scarps forming north–northeast-trending, that stretch west of Kiruna, Lapland. End-glacial intra-plate faults of this extent are very rare in the continental crust and the Pärvie system represents one of the major fault zone structures of this type in the world. Seismological evidence shows that there is still noticeable seismic activity, roughly one event of magnitude 2 per year that can be attributed to the fault. Nevertheless assessing its state of activity is a difficult task due to the extent and remoteness of the area. This study is aimed at the determination of crustal motion around the Pärvie fault zone using the differential inter-ferometric synthetic aperture radar (DInSAR) technique, based on images acquired with the European Space Agency (ESA) satellites European Remote Sensing (ERS) 1, ERS-2, and the Environmental Satellite (ENVISAT). We present results achieved in terms of deformation of the crystalline bedrock along different sectors of the fault where high levels of coherence were obtained, even from image pairs several years apart. This finding does not exclude deformation in other segments, as observing conditions are not always as favourable in terms of data availability.     

Authoring vs. Configuring Affective Agents for Interactive Storytelling

Autonomous characters in interactive storytelling can be supported by using affective agent architectures. The configuration of most current tools for controlling agents is, however, implementation specific and not tailored to the needs of authors. Based on literature review, a questionnaire evaluation of authors’ preferences for character creation, and a case study of an author’s conceptualization of this process, we investigate the different methods of configuration available in current agent architectures, reviewing discrepancies and matches. Given these relations, promising approaches to configuration are identified, based on initial inner states, “global” parameters of characters, libraries of stock characters, and selections of backstory experiences.     

Immobilization of enzymes onto modified polyacrylonitrile membranes: Application of the acyl azide method

Chemical reactions toward acyl azide activated polyacrylonitrile (PAN) and conditions for membrane surface modifications are described. Ultrafiltration (UF) membranes were prepared from PAN homopolymer and copolymer with methyl acrylate. Besides hydrazide formation and nitrosation, a new method to introduce acyl azide groups into carboxyl modified PAN, using azido transfer with diphenyl phosphoryl azide, was developed. Chemical conversions were characterized, especially with Fourier transform infrared spectroscopy. The heterogeneous modifications are not chemically selective due to side reactions and/or incomplete conversion. The pore structure is altered predominately via modified polymer swelling causing changed UF fluxes and selectivities. However, for the modification via PAN reaction with hydroxyl amine, acid hydrolysis, and azido transfer, the initial membrane separations performance is qualitatively preserved. Using the acyl azide ḿethod, amylo-glucosidase (AG) (EC 3.2.1.3) was immobilized onto the modified PAN UF membranes, enabling hydrolysis of starch or maltose to glucose. Enzyme activity was assayed depending on previous chemical modification (azide content) and immobilization (pH) conditions as well as hydrolysis parameters (substrate, conversion during diffusion or UF). The best results (up to 600 mU/cm² at 40°C and pH 5.0) were obtained after modification of PAN membranes via carboxyl creation and azido transfer. AG convalently bound to PAN is not influenced much in its catalytic properties (K_m = 3.48 and 3.1 mmol/L for free and bound AG, respectively, with maltose at 40°C and pH 5.0). Under UF conditions, AG effective activity can be improved by the convective flow through the membrane. UF selectivity for the polymer starch determines effective substrate concentrations in the membrane, thus affecting observed activities and product purities in the filtrate. © 1996 John Wiley & Sons, Inc.     

Yield optimization of a RSFQ voltage doubler

The centers-of-gravity optimization method has been applied to optimize a complex circuit consisting of a dc/SFQ-converter and RSFQ voltage doubler in order to obtain maximum parameter margins. As a result, the margins of all circuit parameters have been enlarged to at least ±35%. This improves the yield of the circuit fabrication process. On the other hand, the upper limiting frequency and the output voltage of the circuit, respectively, are decreased by the yield optimization process.     

Polymere in der diagnostik

Diagnostics are e. g. reagents or combinations of reagents or measure bloodcomponents down to concentrations of 10^?15 mol/1 in reproducable form. To achieve this target diagnostics have to fullfill special requirements in purity, uniformity, producibility and reproducibility. These requirements are also valid for integrated polymers and plastics. Examples of the application of polymers and plastics in diagnostics are e. g. materials for the blood-plasma-separation, the stabilization of proteins, solid phases in immunoassays as reagent tubes, microtiterplates and latexparticles. Reciprocal actions between polymers, plastics, polymer additives, blood and bloodsubstances like proteins in diagnostic tests can be seen as indications to similar effects by the intracorporeal applications of plastics in surgery and in general for contacts of natural materials with plastics, as usual in the foodpacking.     

Modellierung für Integrated Enterprise Balancing

The development of models and methods is a vital element of design science in information systems research. In this paper a formal process modeling language is developed which incorporates IEB (Integrated Enterprise Balancing)/4R (Risk, Return, Regulation, Reporting) requirements formulated by Faisst and Buhl [FaBu05]. This is realized through the inclusion of 4R elements and 4R relations into the new 4R process modeling language. An evaluation of the process modeling language with regard to the assessment criterion “feasibility of implementation” was successfully executed using the meta modeling platform ADONIS. For that purpose the ADONIS modeling language for business processes (ADONIS BPMS) was extended with additional 4R modeling elements. Furthermore a new model type as well as required classes and relation classes have been developed which enable the connection of the 4R process modeling language to the research results of the above mentioned contribution.