Showing papers by "Münster University of Applied Sciences published in 2007"

Morphology and microtopology of cation-exchange polymers and the origin of the overlimiting current.

Abstract: In electrodialysis desalination processes, the operating current density is limited by concentration polarization. In contrast to other membrane processes such as ultrafiltration, in electrodialysis, current transport above the limiting current is possible. In this work, the origin of the overlimiting current at cation-exchange polymers is investigated. We show that, under certain experimental conditions, electroconvection is the origin of the overlimiting conductance. The theory concerning electroconvection predicts a shortening of the plateau length of membranes with increased conductive or geometrical heterogeneity. We investigate the influence of these two parameters and show that the creation of line undulations on the membrane surface normal to the flow direction, having distances in the range of approximately 50−200% of the boundary-layer thickness, lead to an earlier onset of the overlimiting current. The plateau length of the undulated membranes is reduced by up to 60% compared to that of a flat membrane. These results verify the existence of electroconvection as a mechanism destabilizing the laminar boundary layer at the liquid−membrane interface and causing ionic transport above the limiting current density.

Structural variations in rare earth benzoate complexes: Part I. Lanthanum

Abstract: A series of lanthanum benzoate complexes have been prepared and structurally characterised as DMF or DMSO solvates. The structures of these complexes vary considerably as a function of the steric bulk of the ligands and the degree of solvation. With one exception, all of the complexes form coordination polymers. These experimental results are compared to reported data from the Cambridge Structural Database (CSD) in order to study the role of sterically bulky substituents in the structures of lanthanum benzoate complexes. Binding modes vary from the η1 coordination of a carboxylic acid co-ligand to carboxylate ligands adopting a bridging μ-η2 : η1 geometry. The nature of the bridging environment between adjacent lanthanum ions varies significantly in the structures and often several different environments exist within the same structure. Solvent effects are also observed, particularly in cases where the solvent is able to partake in intra- or intermolecular hydrogen bonding.

Synthese von Y2O2(CN2) und Leuchtstoffeigenschaften von Y2O2(CN2):Eu

Abstract: Synthesis of Y2O2(CN2) and Luminescence Properties of Y2O2(CN2):Eu Crystalline powders of the new compound Y2O2(CN2) were prepared by solid state reactions from different mixtures of YCl3/YOCl/Y2O3 and Li2(CN2) at temperatures between 620 °C and 650 °C. Structure refinements based on X-ray powder diffraction revealed that trigonal Y2O2(CN2) crystallizes with a structure that is closely related to that of Y2O2S, whereas linear N-C-N units replace sulphur atoms in Y2O2S. In addition, a hexagonal polytype of Y2O2(CN2) was obtained in which a different stacking sequence of yttrium atoms creates a doubling of the c-axis. Europium-doped samples of Y2O2(CN2) were prepared and the luminescence properties of Y2O2(CN2):Eu are presented.

Low temperature synthesis of calcium cobaltites in a solid state reaction

Abstract: This paper presents synthesis of calcium cobaltites of the nominal composition of Ca3Co4O9 prepared by the solid state reaction. The reaction between CaCO3 and Co3O4 was investigated at 700–900 °C during 20 h and at 800 °C during 2–30 h. Mass changes, phase composition and Co+3, Co+4 content were examined. Stability of the calcined specimens was tested by DTA/TG. It was found that two phases: Ca3Co4O9 and Ca3Co2O6 were present as a result of calcinations above 800 °C. On the other hand, the temperature of 750 °C was too low for calcium cobaltites to be synthesized. Mono-phase material with Ca3Co4O9 phase was obtained after calcinations at 800 °C but non-stoichiometry of the compound and its relation to the calcinations time were found. Once synthesized, the compound was stable up to 900 °C.

The synthesis and characterisation of europium terpyridine-N-oxide complexes

Abstract: Europium complexes of a series of terpyridine-N-oxide ligands have been prepared and structurally characterised by crystallographic studies. While the addition of three equivalents of terpyridine-1-oxide or terpyridine-1,1′-bisoxide results in complexes with nine co-ordinate tricapped trigonal prismatic or monocapped square antiprismatic geometries, respectively, three equivalents of the terpyridine-1,1′,1′-trisoxide yields an unexpected 8 co-ordinate geometry. Luminescence studies of the three complexes in acetonitrile show a typical europium emission spectra, dominated by the 5D0–7F2 transition. While no simple trend in the relative quantum yields could be ascertained, the terpyridine-1-oxide complex was observed to have the most intense luminescence for this set of complexes.

Tool i.e. medical gripping tool, for e.g. examining, body part of patient, has two branches provided, where one branch is deformable during movement and is formed of deformable framework and exhibiting flexible flanges

Abstract: The tool has two branches provided, where one branch (1) is deformable during a movement and is formed of a deformable framework. The deformable branch exhibits flexible flanges (2), where a connecting unit (4) e.g. rods, extends between the flexible flanges. The flanges exhibit v-shaped recesses, where the connecting unit lies in the v-shaped recesses, and the thickness of the connecting unit corresponds to a breadth of the recesses. The shape of ends of the connecting unit and the recesses corresponds to one another.

A: Algebraic Structures

Abstract: 2020/21 SV EN PLED F/Pi 7151 X E1 X Course Web Page Examinations 2019/20 SV EN PLED F/Pi 7151 X E1 X Course Web Page Examinations 2018/19 SV EN PLED F/Pi 7151 X E1 X Course Web Page Examinations 2017/18 SV EN PLED F/Pi 7151 X E1 X Course Web Page Examinations 2016/17 SV EN UNB 7151 X E1 X Course Web Page Examinations 2015/16 SV EN UNB 7151 X E1 X Course Web Page Examinations 2014/15 SV EN UNB 7151 X E1 X Course Web Page Examinations 2013/14 SV EN UNB 7151 X E1 X Course Web Page Examinations 2012/13 SV EN UN1 7151 X E1 X Course Web Page Examinations

Verfahren zur identifizierung von kunststoffen

Abstract: Die Erfindung betrifft ein Verfahren zur Identifizierung von Kunststoffen durch Dotieren eines Kunststoffs mit Metallen bzw Metallderivaten, Verarbeiten des Kunststoffs zu einem Formkorper und quantitative Analyse der eingebrachten Metalle bzw Metallderivate mittels einer Analysemethode, die eine Vermessung von festem Probenmaterial ermoglicht Die Erfindung betrifft ferner einen Standardsatz zur Kalibrierung eines Analysegerats, das in den vorstehend genannten Verfahren verwendet werden kann, umfassend mindestens zwei Kalibrierstandards, wobei jeder Kalibrierstandard einen Kunststoffformkorper enthalt, der mit mindestens einem Metall ausgewahlt aus La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Sc, Ir, Pt, Rh, Au, Os und V dotiert ist

Fehlermöglichkeiten beim Herstellungsprozess von Tunnelinnenschalen

Abstract: Der vorliegende Beitrag befasst sich mit moglichen Fehlern, die wahrend des Herstellungsprozesses von Tunnelinnenschalen entstehen konnen. Dabei werden die einzelnen Herstellungsphasen, Arbeitsablaufe sowie unterschiedliche Rahmenbedingungen in Bezug auf mogliche Schaden und Mangel an der Tunnelinnenschale einer Analyse und Bewertung unterzogen. Dies beginnt mit den vorbereitenden Masnahmen zur Verlegung der Abdichtung und dem Einbau der Abdichtung, geht uber den Bewehrungseinbau, die Ausbildung des Schalwagens bis zum Betonieren der Schale sowie deren Nachbehandlung und die Beseitigung entstandener Fehlstellen. Es erfolgt anschliesend eine Zuordnung in unterschiedliche Verantwortungsbereiche bzw. Ursachen. Anhand dieser Untersuchungen lassen sich Empfehlungen zur Reduzierung und Vermeidung von Fehlerquellen sowie zur Qualitatssteigerung von Tunnelinnenschalen ableiten. Source of Errors during the Manufacturing Process of Internal Tunnel Shells This present contribution is concerned with possible mistakes which can develop during the production process of internal tunnel shells. The individual manufacture phases, operational sequences as well as the different basic conditions regarding possible damage and an evaluation and analysis of the internal tunnel shells deficiencies are submitted. This begins with the preparatory measures for the laying of the insulation and the mounting of the insulation, the reinforcement mounting, the drilling of the formwork car, and the concreting of the sealing and the installation of the sealing, the armouring installation. An assignment occurs afterwards of different areas of responsibility and causes. On the basis of these investigations, recommendations are made regarding the reduction and avoidance of sources of error as well as the quality increase for internal tunnel shells.

Adaptive optics at the PHELIX laser

Abstract: GSI Darmstadt currently builds a high-energy petawatt Nd:glass laser system, called PHELIX (Petawatt High-Energy Laser for Heavy-Ion Experiments). PHELIX will offer the world-wide unique combination of a high current, high-energy heavy-ion beam with an intense laser beam. Aberrations due to the beam transport and due to the amplification process limit the focusability and the intensity at the target. We have investigated the aberrations of the different amplification stages. The pre-amplifier stage consists of three rod-amplifiers which cause mainly defocus, but also a small part of coma and astigmatism. The main amplifier consists of five disk amplifiers with a clear aperture of 315 mm. These large disk-amplifiers cause pump-shot aberrations which occur instantly. After a shot, the disk amplifiers need a cooling time of several hours to relax to their initial state. This limits the repetition rate and causes long-term aberrations. We will present first measurements of the pump-shot and long-term aberrations caused by the pre- and the main amplifier in a single-pass configuration. In this context, we will present the adaptive optics system which is implemented in the PHELIX beam line and discuss its capability to compensate for the pump-shot and long-term aberrations.

Insider attacks enabling data broadcasting on crypto-enforced unicast links

Abstract: Most wireless communication techniques rely on broadcast media on the physical layer, i.e., the actual signal can be received by any party in a certain coverage area. Furthermore, there are cable-based networks, such as HFC (hybrid fiber/coaxial) networks that use a shared transmission medium (coaxial cable) to bridge the last mile. A common means to perform secure unicast (point-to-point) communication over such wireless or shared transmission media is by applying cryptographic protocols on higher layers of the protocol stack. As of today, a common assumption in the design and analysis of such communication protocols is that both end-points (user and carrier) behave correctly according to the cryptographic protocol, because they want to preserve security against outsiders who might be sniffing private communication of legitimate users. However, under certain conditions users may not be interested in protecting their unicast communication against outsiders. Instead, users may try to extend their communication power/resources by means of insider attacks against the communication protocol. Such insider attacks pose new threats to providers of communication services and have, to the best of our knowledge, been neglected so far. In this paper we will discuss insider attacks against several communication systems that can break the unicast communication enforced by cryptographic means by the carrier of the communication infrastructure.

Method for the identification of plastics

Abstract: The invention relates to a method for identifying plastics by doping a plastic with metals or metal derivatives, processing the plastic into a molded article, and quantitatively analyzing the introduced metals or metal derivatives by means of an analytical process that allows solid sample material to be measured. The invention further relates to a standard kit for calibrating an analytical device that can be used in said methods. The inventive standard set comprises at least two calibration standards, each of which contains a molded plastic article which is doped with at least one metal selected among La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Sc, Ir, Pt, Rh, Au, Os, and V.

Gripper tool e.g. laparoscopic forceps, for gripping e.g. body part, has two lines including flexible supported gripping surfaces or gripping surface sections, which are disposed during gripping process in form fit manner to gripped object

Abstract: The tool has two lines for gripping objects e.g. body parts, where one of the lines includes a flexible supported gripping surface or flexible supported gripping surface sections, which are disposed during gripping process in a form fit manner to a gripped object. The gripping surface is formed by covering area of filled cushion, which is arranged at lines, where the cushion is filled with fluid or with anisotropy material.

Ethische und verbraucherpolitische Aspekte sowie Limitationen der Beobachtungen in der internetbasierten Marktforschung

Abstract: Obervation as a method for gaining information in the internet offers new opportunities and potentials in market research. Although, its application is somehow limited because of consumer related criticism and public scrutiny related to ethical and privacy concerns. This paper discusses some central ethical and consumer and society related aspects and limitations of the application of observation methods in online market research.

Multilevel laser medium has layer that is made of laser material, which is excited to stimulate emission on laser wavelength, and has another layer that is made of absorber material that works to absorb same wavelength

Abstract: The multilevel laser medium has a layer (3) that is made of a laser material, which is excited to stimulate emission on a laser wavelength, and has another layer (1) that is made of an absorber material that works to absorb the same wavelength. The two layers are optically coupled together directly or over an intermediate layer (2). The entire layer structure has five-angular form, and extends perpendicularly to the cross section over a desired length. An independent claim is included for gadolinium scandium aluminum garnet crystal.

Auftrag und Handlungsmöglichkeiten der Jugendhilfe bei häuslicher Gewalt

Abstract: Die Jugendhilfe besteht aus staatlichen (offentliche Trager) und nicht staatlichen (freie Trager) Diensten, Angeboten und Einrichtungen zur Erziehung und Unterstutzung von Kindern, Jugendlichen und Familien. Sie ist gesetzlich im SGB VIII geregelt und hat einen Handlungsauftrag im Hinblick auf die Verbesserung der Sozialisationsbedingungen fur die nachwachsende Generation. Insoweit ist die Jugendhilfe bei hauslicher Gewalt immer dann zustandig, wenn Kinder in dem Haushalt mit Partnergewalt leben. Bei dem Phanomen hausliche Gewalt ist insoweit die Prufung einer moglichen Kindeswohlgefahrdung grundsatzlich geboten. Unabhangig davon, ob das Kind selbst von Gewalthandlungen unmittelbar betroffen ist oder nicht. Gewalt gegen Frauen korreliert haufig mit Gewalt gegen Kinder: Vergewaltigung und Misshandlung von Frauen durch ihre Partner, Ehemanner, Freunde (auch ehemalige); sexueller Missbrauch, Misshandlung und Vernachlassigung von Madchen und auch Jungen durch Vater, soziale Vater und Freunde der Mutter und auch durch die Mutter selbst; Gewalt und sexualisierte Gewalt unter den Kindern. In gewaltbelasteten Familien treten diese Phanomene in wechselnden, sich gegenseitig beeinflussenden Auspragungen und Erscheinungsformen auf. Etwa 30%-60% der Kinder, die Partnerschaftsgewalt miterleben mussen, werden selber auch misshandelt (Kindler/Drechsel 2003, S.218). Erst jungst wird in der Jugendhilfe auch ein Augenmerk auf die Kinder geworfen, die fortgesetzt Partnergewalt beobachten mussen (Kindler 2002). Bei Gewalt auf der Partnerebene sind Kinder mit betroffen, d.h. sie sind Teilnehmende an der Gewaltsituation und insoweit gefahrdet.

Optimal control of constrained time lag systems: Necessary conditions and numerical treatment

Abstract: We consider retarded optimal control problems with constant delays in state and control variables under mixed controlstate inequality constraints. First order necessary optimality conditions in the form of Pontryagin's minimum principle are presented and discussed as well as numerical methods based upon discretization techniques and nonlinear programming. The minimum principle for the considered problem class leads to a boundary value problem which is retarded in the state dynamics and advanced in the costate dynamics. It can be shown that the Lagrange multipliers associated with the programming problem provide a consistent discretization of the advanced adjoint equation for the delayed control problem. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)