TY - GEN A1 - Samm, Doris A1 - Meurer, Marcel T1 - Die elektrische Leitung und Supraleitung N2 - Die Lerneinheit stellt in anschaulicher Weise die verschiedenen Modelle der elektrischen Leitung dar und führt über diese zur Erklärung der Supraleitung. Effekte und Anwendungen der Supraleitung werden in Animationen und Bildern vorgeführt. Ein umfangreiches Glossar erläutert wichtige Begriffe. KW - Elektrische Leitung KW - Supraleitung KW - Elektronengas KW - Bändermodell KW - Festkörper KW - Elektrische Leitung KW - Supraleitung Y1 - 2003 ER - TY - BOOK A1 - Merten, Sabine T1 - Verbesserung der Ausbildung in der Mikrosystemtechnik - virtuelle Labore bereiten auf die Herstellung realer Drucksensoren vor (2 Fassungen: konvertiert und original N2 - Die Ausbildung in Hochtechnologien wie beispielsweise der Mikrosystemtechnik ist oft durch einen hohen Grad an Komplexität charakterisiert. Damit verbunden sind hohe Kosten für die Errichtung und den Betrieb der speziellen Laborräume und ihre häufig geringe Verfügbarkeit für die Studierenden. Zukünftige Ingenieure sammeln während ihrer Ausbildung aus diesen Gründen nur in beschränktem Umfang praktische Erfahrungen. Die Industrie hingegen fordert Personal mit hoher fachlicher Kompetenz, also fundiertem theoretischen Wissen und umfangreichen praktischen Kenntnissen. Dieser Diskrepanz – qualifizierte Ingenieure auf der einen Seite und eine eher theoretisch ausgerichtete Ausbildung auf der anderen Seite – wird mit einem neuen Blended-Learning-Konzept für MST-Technologiepraktika begegnet. Lernende werden über ein virtuelles Labor, das einen echten Reinraum mit realen Anlagen simuliert, intensiv auf reale Laborpraktika vorbereitet. Dabei geht es im virtuellen Labor gleichermaßen um die Vermittlung von Theorie und Praxis. Nur trainierte Teilnehmer mit einer intensiven Vorbereitung sind in der Lage, relativ eigenständig ein echtes MST-Bauteil innerhalb des anschließenden einwöchigen Laborkurses zu fertigen. Die Wirksamkeit des Konzeptes und die Steigerung des Lernerfolges durch die kombinierten virtuellen und realen Laborkurse wurden im Rahmen der Dissertation begleitend untersucht. Die Ergebnisse flossen direkt in die Weiterentwicklung der Technologiepraktika ein. Die Konzepte und Erkenntnisse sind zudem sehr interessant für die Entwicklung von Blended-Learning-Angeboten in ähnlichen oder anderen Fachgebieten sowie für weitere Bildungseinrichtungen. (Die Dissertation liegt hier in 2 Fassungen vor: Die Originalfassung ist nur bei guter Rechnerausstattung und guter Netzanbindung nutzbar, die konvertierte Fassung ist unverändert, allerdings sind Qualitätseinbußen beim Ausdruck einiger Grafiken möglich) N2 - Education in high technologies, like e.g. Microsystems technology, is usually characterized by a high degree of complexity. In addition it is usually connected with large economic efforts for invest, operation and maintenance of the special laboratory facilities. The access to such facilities for educational purposes is often quite limited. Therefore engineering students rather rarely gather practical experience in such technologies during their university studies. In contrast, industry has a large demand for engineers with high professional competence, i.e. profound theoretical knowledge combined with substantial practical experience. The newly developed blended learning concept for MST laboratory training tries to bridge the gap between the need for qualified engineers and the more theoretical university education. The learners prepare intensively for real hands-on clean room trainings with a virtual technology laboratory, i.e. a computer simulation of the clean room machines and the corresponding processes. In the virtual technology laboratory the students brush up their theoretical knowledge and at the same time learn to operate the complex clean room machines. Only well trained and intensively prepared students are capable to produce a fully functional MST component within a compact clean room laboratory course of only one week duration and an only modest amount of supervision. The effectivity of this concept and the increase of the learning success due to the specific mixture of virtual and real laboratory sessions has been accompanied and analysed by this dissertation. The results have been used to further improve the laboratory courses. Concepts and results are also very attractive for comparable blended learning proposals in other technical disciplines. KW - Mikrosystemtechnik KW - Virtuelles Laboratorium KW - Lernprogramm KW - Hochschule / Lehre / Evaluation KW - Computersimulation KW - Drucksensor KW - Blended-Learning KW - Reinraumpraktikum KW - blended learning KW - hands-on cleanroom training Y1 - 2005 N1 - Zugl.: Saarbrücken, Univ., Diss., 2005 ER - TY - JOUR A1 - Baroud, G. A1 - Wu, J.Z. A1 - Bohner, M A1 - Sponagel, Stefan A1 - Steffen, T. T1 - How to determine the permeability for cement infiltration into osteoporotic cancellous bone JF - Medical Engineering & Physics. 25 (2003), H. 4 N2 - Cement augmentation is an emerging surgical procedure in which bone cement is used to infiltrate and reinforce osteoporotic vertebrae. Although this infiltration procedure has been widely applied, it is performed empirically and little is known about the flow characteristics of cement during the injection process. We present a theoretical and experimental approach to investigate the intertrabecular bone permeability during the infiltration procedure. The cement permeability was considered to be dependent on time, bone porosity, and cement viscosity in our analysis. In order to determine the time-dependent permeability, ten cancellous bone cores were harvested from osteoporotic vertebrae, infiltrated with acrylic cement at a constant flow rate, and the pressure drop across the cores during the infiltration was measured. The viscosity dependence of the permeability was determined based on published experimental data. The theoretical model for the permeability as a function of bone porosity and time was then fit to the testing data. Our findings suggest that the intertrabecular bone permeability depends strongly on time. For instance, the initial permeability (60.89 mm4/N.s) reduced to approximately 63% of its original value within 18 seconds. This study is the first to analyze cement flow through osteoporotic bone. The theoretical and experimental models provided in this paper are generic. Thus, they can be used to systematically study and optimize the infiltration process for clinical practice. KW - Osteoporose KW - Permeabilität KW - Viskose Strömung KW - Viskosität KW - Vertebroplastie KW - Cement infiltration KW - Vertebroplasty KW - Osteoporosis KW - Permeability KW - Experiment KW - Analysis KW - Viscous flow Y1 - 2003 SN - 1350-4533 SP - 283 EP - 288 ER - TY - JOUR A1 - Kühn, Raoul-Roman A1 - Haugner, Werner A1 - Staat, Manfred A1 - Sponagel, Stefan T1 - A Two Phase Mixture Model based on Bone Observation N2 - An optimization method is developed to describe the mechanical behaviour of the human cancellous bone. The method is based on a mixture theory. A careful observation of the behaviour of the bone material leads to the hypothesis that the bone density is controlled by the principal stress trajectories (Wolff’s law). The basic idea of the developed method is the coupling of a scalar value via an eigenvalue problem to the principal stress trajectories. On the one hand this theory will permit a prediction of the reaction of the biological bone structure after the implantation of a prosthesis, on the other hand it may be useful in engineering optimization problems. An analytical example shows its efficiency. KW - Knochen KW - Knochenbildung KW - Knochenchirugie KW - Strukturanalyse KW - Schwammknochen KW - Knochendichte KW - Wolffsches Gesetz KW - bone structure KW - bone density KW - Wolff's Law KW - cancellous bone Y1 - 2004 ER - TY - JOUR A1 - Vu, Duc-Khoi A1 - Staat, Manfred T1 - An algorithm for shakedown analysis of structure with temperature dependent yield stress N2 - This work is an attempt to answer the question: How to use convex programming in shakedown analysis of structures made of materials with temperature-dependent properties. Based on recently established shakedown theorems and formulations, a dual relationship between upper and lower bounds of the shakedown limit load is found, an algorithmfor shakedown analysis is proposed. While the original problem is neither convex nor concave, the algorithm presented here has the advantage of employing convex programming tools. KW - Einspielen KW - Temperaturabhängigkeit KW - Fließgrenze KW - Shakedown KW - shakedown analysis KW - yield stress Y1 - 2004 ER - TY - JOUR A1 - Staat, Manfred T1 - Direct FEM Limit and Shakedown Analysis with Uncertain Data N2 - The structural reliability with respect to plastic collapse or to inadaptation is formulated on the basis of the lower bound limit and shakedown theorems. A direct definition of the limit state function is achieved which permits the use of the highly effective first order reliability methods (FORM) is achieved. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis. The limit state function and its gradient are obtained from a mathematical optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error, leading to highly effective and precise reliability analyses. KW - Finite-Elemente-Methode KW - Einspielen KW - FEM KW - Einspielanalyse KW - shakedown KW - limit load KW - reliability analysis KW - FEM KW - direct method Y1 - 2000 ER - TY - GEN A1 - Bellenberg, Markus T1 - Optimierung einer Roboter-Schweißzelle als Basis eines E-Learning Systems T1 - Optimization of a Robot-welding Station as the Basis for an E-Learning System N2 - Ziel war die technische Überarbeitung und Optimierung des vorliegenden Prototypen, um eine Basis für ein E-Learning System (Internet unterstütztes Lernen) zu schaffen. Zu diesem Zweck wurde das Programm der Robotersteuerung neu erstellt, notwendige mechanische Änderungen an Roboterequipment und Materialförderung vorgenommen sowie eine neue Internet-Anbindung geschaffen. Wesentliche Ergebnisse der Arbeit sind: • Erzeugen roboterbasierter kreisinterpolierter Bahnschweißnähte • Kommunikation des Lernsystems via Internet • Lernorientierte Steuerungssoftware N2 - The main goal of this final thesis was the revision and optimization of the given prototype as a basis for an E-Learning environment. All components of the system, including specific technical aspects, are discussed in order to create the basis for future training documentation. Similarly, the programs for the robot motion sequences and welding processes were renewed in order to create well-structured, clear and properly documented software that is suitable for use in a formal training program. KW - Roboter KW - MAG-Schweißen KW - MIG-Schweißen KW - Schweißen KW - Mechatronik KW - Kawasaki KW - E-Learning KW - Roboter-Schweißen KW - welding KW - welded joint KW - mechatronics Y1 - 2002 ER - TY - GEN A1 - Balzar, Christoph Rupert T1 - Land in land N2 - [...] Darin suche ich „Zwischenräume“ in der digitalen Verschmelzung von Fotos unterschiedlicher Orte und durchleuchte diese neu geschaffenen Landschaften auf ihren Sinn für mich. Anhand der so ge-wonnenen Erkenntnisse belebe ich diese Plätze später mit Menschen, Tieren und Fundstücken, die mir das Schicksal auf meinen „Walkabouts“ durch den australischen Kontinent zugespielt hat und denen ich zu den neu entstandenen Orten passende Bedeutungen beimesse. [...] Neben meinen flächigen, fotografischen und installativen Werken stelle ich auch ein umfassendes Rahmen- und Begleitprogramm zur Ausstellung her, beispielsweise eine CI und eine Homepage. KW - Digitale Photographie KW - Photomontage KW - Naturphotographie KW - Aborigines KW - Fotografie KW - Digitale Montage KW - Bilderserie KW - Ureinwohner KW - Australien KW - Inszenierte Photographie KW - Photography KW - Digital montage KW - Series KW - Aboriginal people KW - Australia KW - Set-up photography Y1 - 2005 ER - TY - JOUR A1 - Kämper, Klaus-Peter A1 - Picard, Antoni A1 - Brill, Manfred A1 - Cassel, Detlev A1 - Jentsch, Andreas A1 - Merten, Sabine A1 - Rollwa, Markus T1 - The Virtual Clean Room - a new tool in teaching MST process technologies N2 - The Virtual Clean Room - a new tool in teaching MST process technologies University education in high-technology fields like MST is not complete without intensive laboratory sessions. Students cannot fully grasp the complexity and the special problems related to the manufacturing of microsystems without a thorough hands-on experience in a MST clean room. KW - Virtuelle Maschine KW - VM KW - Mikrosystemtechnik KW - MST KW - virtual clean room Y1 - 2003 ER - TY - JOUR A1 - Picard, Antoni A1 - Brill, Manfred A1 - Cassel, Detlev A1 - Jentsch, Andreas A1 - Rollwa, Markus A1 - Kämper, Klaus-Peter A1 - Merten, Sabine T1 - Neue Medien für die praktische MST-Ausbildung N2 - Im Studiengang Mikrosystemtechnik des Fachhochschulstandortes Zweibrücken werden zwei neue moderne Anlagen für die Herstellung von mikrotechnischen Komponenten in Betrieb genommen: Ein Oxidationsofen für Herstellung dünner Oxidschichten auf Silizium-Einkristallen und eine Belichtungsapparatur für die Fotolithografie - das Besondere an diesen Anlagen: Sie existieren nur virtuell, d.h. als Animationen in einer Computerwelt. KW - Mikrosystemtechnik KW - Photolithographie KW - Mikrotechnik KW - mikrotechnische Komponenten KW - Oxidationsofen KW - Oxidschicht KW - multimediale Lernsoftware KW - micro technology KW - micro-technical components KW - oxidation furnace KW - oxide coating Y1 - 2002 ER - TY - CHAP A1 - Merten, Sabine A1 - Kämper, Klaus-Peter A1 - Brill, Manfred A1 - Picard, Antoni A1 - Cassel, Detlev A1 - Jentsch, Andreas A1 - Rollwa, Markus T1 - Vom virtuellen Wafer zum realen Drucksensor N2 - Das Technologiepraktikum „Virtuelle Sensor-Fertigung“ ist ein Beispiel für die medientechnische Aufbereitung von Lern- und Lehrmaterial unter didaktischen Gesichtspunkten. Studierende lernen einen Fertigungsprozess mit Hilfe von virtuellen Maschinen kennen, bevor sie die reale Prozesskette im Laborpraktikum im Reinraum durchführen. N2 - The technology course “Fabrication of a microsensor” represents a multimediabased approach towards education in high technology production in consideration of didactical aspects. The students learn the operation of a complex microfabrication line with the help of virtual fabrication machines before they perform the actual process in a hands-on training in an actual clean room. KW - Virtuelle Maschine KW - VM KW - Virtuelle Sensor-Fertigung KW - virtual fabrication of a microsensor Y1 - 2003 ER - TY - CHAP A1 - Merten, Sabine A1 - Kämper, Klaus-Peter A1 - Brill, Manfred A1 - Picard, Antoni A1 - Cassel, Detlev A1 - Jentsch, Andreas A1 - Rollwa, Markus T1 - Virtuelle Sensor-Fertigung: Hightech mit LabVIEW N2 - Eine neue Generation von Praktika an Hochschulen wächst heran. Moderne Wege beim Verstehen und Erlernen naturwissenschaftlicher Zusammenhänge sowie industrieller Fertigungsprozesse sind gefordert. Das Technologiepraktikum „Virtuelle Sensor- Fertigung“, entwickelt im Verbundprojekt INGMEDIA an den Fachhochschulen Aachen und Zweibrücken, trägt als neuartiges Lern- und Lehrmodul dieser Forderung Rechnung. Die Studierenden lernen einen vollständigen Fertigungsprozess mit Hilfe von virtuellen, in LabVIEW programmierten Maschinen kennen, bevor sie die reale Prozesskette im Reinraum durchführen. N2 - A new generation of university laboratory courses is presently being developed. Modern concepts for the understanding and learning of applied science and industrial fabrication processes are required. The technology course “Fabrication of a microsensor”, developed by the Universities of Applied Sciences Aachen and Zweibrücken in the joint research project INGMEDIA, represents a new approach towards education in high technology production. The students learn the operation of the complex microfabrication line with the help of virtual fabrication machines, programmed in LabVIEW, before they perform the actual process in a genuine clean room. KW - LabVIEW KW - Virtuelle Sensor-Fertigung KW - Fertigungsprozess KW - virtuelle Maschinen KW - virtual sensor fabrication KW - manufacturing process KW - virtual KW - virtual machines Y1 - 2003 ER - TY - CHAP A1 - Fabo, Sabine T1 - Audio-visual hybrids : between immersion and detachment N2 - Close interrelations between sound and image are not a mere phenomenon of today’s multimedia technology. The idea of the synthesis of different media lies at the core of the concept of the Gesamtkunstwerk in the second half of the 19th century and it can also be traced back to the synaesthesia debate at the beginning of the 20th century [...]. KW - Elektronische Kunst KW - Klangkunst KW - Hybride Kunst KW - Medienkunst KW - Hybrid Art KW - Sound Art KW - Audio-visual Art Y1 - 2004 ER - TY - JOUR A1 - Fabo, Sabine T1 - Das Museum lebt? Der Diskurs der Vernetzung im virtuellen Kunstraum JF - Zeitenblicke N2 - Kunstwerke sowie ihre Präsentation und Vermittlung werden zunehmend von digitalen Technologien unterstützt. Virtuelle Ausstellungen, Internet-Projekte und komplexe Datenarchive stellen das Kunstwerk in einen medialen Kontext, der weit über das Moment einer technischen Reproduzierbarkeit hinausgeht. Das allgegenwärtige Konzept der Vernetzung dynamisiert Kunst, ihre Rezipienten und Ausstellungsorte. Die Beziehungen zwischen diesen Feldern werden mit Hilfe physiologischer Metaphern definiert und visualisiert. Frühere Speicher und Archive geraten in einen prozessualen Sog, in dem alles fluktuiert, sich kurzweilig verknüpft, auflöst und in permanente Dialoge mit seiner Umgebung tritt - das virtuelle Museum gerät in aktuellen Standortbestimmungen in die definitorische Nähe des Künstlichen Lebens. KW - Elektronische Kunst KW - Netzkunst KW - Museum KW - Museumsorganisation KW - Virtuelles Museum KW - Virtuelle Ausstellung KW - Digitales Museum KW - Vernetzung KW - Elektronische Kunst KW - Virtual Art KW - Virtual Museum KW - Virtual Exhibition KW - Digital Museum KW - Electronic Art Y1 - 2003 VL - 2(2003) IS - 1 ER - TY - JOUR A1 - Staat, Manfred T1 - LISA - a European project for FEM-based limit and shakedown analysis N2 - The load-carrying capacity or the safety against plastic limit states are the central questions in the design of structures and passive components in the apparatus engineering. A precise answer is most simply given by limit and shakedown analysis. These methods can be based on static and kinematic theorems for lower and upper bound analysis. Both may be formulated as optimization problems for finite element discretizations of structures. The problems of large-scale analysis and the extension towards realistic material modelling will be solved in a European research project. Limit and shakedown analyses are briefly demonstrated with illustrative examples. KW - Einspielen KW - Traglast KW - Finite-Elemente-Methode KW - Traglastanalyse KW - Einspielanalyse KW - FEM KW - limit analysis KW - shakedown analysis Y1 - 2001 ER - TY - CHAP A1 - Staat, Manfred T1 - Design by Analysis of Pressure Components by non-linear Optimization N2 - This paper presents the direct route to Design by Analysis (DBA) of the new European pressure vessel standard in the language of limit and shakedown analysis (LISA). This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for some examples from the DBA-Manual. One observation from the examples is, that the optimisation approach gives reliable and close lower bound solutions leading to simple and optimised design decision. KW - Analytischer Zulaessigkeitsnachweis KW - FEM KW - Einspiel-Analyse KW - design-by-analysis KW - finite element analysis KW - limit and shakedown analysis Y1 - 2003 ER - TY - JOUR A1 - Staat, Manfred T1 - Basis Reduction for the Shakedown Problem for Bounded Kinematic Hardening Material N2 - Limit and shakedown analysis are effective methods for assessing the load carrying capacity of a given structure. The elasto–plastic behavior of the structure subjected to loads varying in a given load domain is characterized by the shakedown load factor, defined as the maximum factor which satisfies the sufficient conditions stated in the corresponding static shakedown theorem. The finite element dicretization of the problem may lead to very large convex optimization. For the effective solution a basis reduction method has been developed that makes use of the special problem structure for perfectly plastic material. The paper proposes a modified basis reduction method for direct application to the two-surface plasticity model of bounded kinematic hardening material. The considered numerical examples show an enlargement of the load carrying capacity due to bounded hardening. KW - Finite-Elemente-Methode KW - Einspielen KW - Basis Reduktion KW - konvexe Optimierung KW - FEM KW - Druckgeräte KW - Basis reduction KW - Convex optimization KW - FEM KW - Shakedown analysis Y1 - 2000 ER - TY - JOUR A1 - Staat, Manfred T1 - Shakedown and ratchetting under tension-torsion loadings: analysis and experiments N2 - Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis. KW - Einspielen KW - Einspielen KW - Ratchetting KW - Zug-Druck Belastung KW - shakedown KW - ratchetting KW - tension–torsion loading Y1 - 2003 ER - TY - JOUR A1 - Staat, Manfred T1 - Direct finite element route for design-by-analysis of pressure components N2 - In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion. KW - Einspielen KW - Plastizität KW - Deformation KW - Analytischer Zulaessigkeitsnachweis KW - Einspiel-Analyse KW - fortschreitende plastische Deformation KW - alternierend Verformbarkeit KW - Einspiel-Kriterium KW - Design-by-analysis KW - Shakedown analysis KW - Progressive plastic deformation KW - Alternating plasticity KW - Shakedown criterion Y1 - 2005 ER - TY - JOUR A1 - Staat, Manfred T1 - Local and global collapse pressure of longitudinally flawed pipes and cylindrical vessels N2 - Limit loads can be calculated with the finite element method (FEM) for any component, defect geometry, and loading. FEM suggests that published long crack limit formulae for axial defects under-estimate the burst pressure for internal surface defects in thick pipes while limit loads are not conservative for deep cracks and for pressure loaded crack-faces. Very deep cracks have a residual strength, which is modelled by a global collapse load. These observations are combined to derive new analytical local and global collapse loads. The global collapse loads are close to FEM limit analyses for all crack dimensions. KW - Finite-Elemente-Methode KW - Grenzwertberechnung KW - Axialbelastung KW - FEM KW - Grenzwertberechnung KW - Axialbelastung KW - Traglastanalyse KW - Limit analysis KW - Global and local collapse KW - Axially cracked pipe KW - Pressure loaded crack-face Y1 - 2005 ER -