Chaotic transport by a turnstile mechanism in 4D symplectic maps

Many systems in nature, e.g. atoms, molecules and planetary motion, can be described as Hamiltonian systems. In such systems, the transport between different regions of phase space determines some of their most important properties like the stability of the solar system and the rate of chemical reactions. While the transport in lower-dimensional systems with two degrees of freedom is well understood, much less is known for the higher-dimensional case. A central new feature in higher-dimensional systems are transport phenomena due to resonance channels. In this thesis, we clarify the complex geometry of resonance channels in phase space and identify a turnstile mechanism that dominates the transport out of such channels. To this end, we consider the coupled standard map for numerical investigations as it is a generic example for 4D symplectic maps. At first, we visualize resonance channels in phase space revealing their highly non-trivial geometry. Secondly, we study the transport away from such channels. This is governed by families of hyperbolic 1D-tori and their stable and unstable manifolds. We provide an approach to measure the volume of a turnstile in higher dimensions as well as the corresponding transport. From the very good agreement of the two measurements we conclude that these structures are a suitable generalization of the well-known 2D turnstile mechanism to higher dimensions.Viele Systeme in der Natur, z.B. Atome, Moleküle und Planetenbewegungen, können als Hamilton'sche Systeme beschrieben werden. In solchen Systemen bestimmt der Transport zwischen verschiedenen Regionen des Phasenraums einige ihrer wichtigsten Eigenschaften wie die Stabilität des Sonnensystems und die Geschwindigkeit chemischer Reaktionen. Während der Transport in niedrigdimensionalen Systemen mit zwei Freiheitsgraden gut verstanden ist, ist für den höherdimensionalen Fall deutlich weniger bekannt. Eine zentrales neues Merkmal von höherdimensionalen Systemen sind Transportphänomene aufgrund von Resonanzkanälen. In dieser Arbeit verdeutlichen wir die komplexe Geometrie von Resonanzkanälen im Phasenraum und identifizieren einen Drehkreuzmechanismus, der den Transport aus einem solchen Kanal heraus dominiert. Zu diesem Zweck betrachten wir die gekoppelte Standardabbildung für numerische Untersuchungen, da sie ein generisches Beispiel für 4D symplektische Abbildungen ist. Zuerst visualisieren wir Resonanzkanäle im Phasenraum und zeigen ihre höchst nicht-triviale Geometrie. Zweitens untersuchen wir den Transport weg von solchen Kanälen. Dieser wird durch Familien von hyperbolischen 1D-Tori sowie deren stabile und instabile Mannigfaltigkeiten bestimmt. Wir stellen einen Ansatz zur Messung sowohl des eingeschlossenen Volumens in höheren Dimensionen als auch des entsprechenden Transports vor. Aus der sehr guten Übereinstimmung der beiden Messungen schließen wir, dass diese Strukturen eine geeignete Verallgemeinerung des bekannten 2D Drehkreuzmechanismus in höheren Dimensionen sind

Operating Power Grids with Few Flow Control Buses

Future power grids will offer enhanced controllability due to the increased availability of power flow control units (FACTS). As the installation of control units in the grid is an expensive investment, we are interested in using few controllers to achieve high controllability. In particular, two questions arise: How many flow control buses are necessary to obtain globally optimal power flows? And if fewer flow control buses are available, what can we achieve with them? Using steady state IEEE benchmark data sets, we explore experimentally that already a small number of controllers placed at certain grid buses suffices to achieve globally optimal power flows. We present a graph-theoretic explanation for this behavior. To answer the second question we perform a set of experiments that explore the existence and costs of feasible power flow solutions at increased loads with respect to the number of flow control buses in the grid. We observe that adding a small number of flow control buses reduces the flow costs and extends the existence of feasible solutions at increased load.Comment: extended version of an ACM e-Energy 2015 poster/workshop pape

Business Model Scenarios for Digital Textile Microfactories

In several industries the concept of Microfactories has been developed and their potentials are still subject of research and development. Also in the Textile and Clothing Industry this concept of a digitally networked end-to-end digital design and production process finds its first realizations in different applications. Such a Digital Textile Microfactory can cover a complete value creating chain comprising all design and production steps from the customer to the ready-made product. It relies on virtual models of the process steps involved, as well as of the materials, the products, and the customers. The digital backbone allows for speed, efficiency, high quality, and deep consumer interaction leading to a great innovation potential in a wide area of applications and Business Models. They range from B2B types, where they can support and speed up the prototyping phase of product development (sampling) up to B2C settings for the innovative production of individualized products, including reordering as well as event-driven production and locally centred production. But in spite of the potential benefits of a Digital Textile Microfactory, there are still just a few realizations seen in the industry due to investment risks and uncertainty with regards to new Business Models. The goal of this paper is to explore Business Model scenarios for a Digital Textile Microfactory that uses digital textile printing as a core process. We first describe the economic characteristics of the Textile and Clothing Industry, and then the digital technology and process underlying such a Digital Textile Microfactory. Based on this description, we then explore different B2B and B2C application scenarios – developed in previous European and German research projects – and settings for related Business Models

Customer Perspective On The Purchase and Use Of Sustainable And Innovative Furniture In A Co-Creation Process

For developing a European industrial cooperation and involvement in the furniture industry, the international research project INEDIT conducted a survey for furniture customers. By finding out the needs and wishes of the customer regarding innovative products and the production process the project will establish a new way for designing and producing furniture. Within INEDIT a platform is built on which customized, technologically innovative and sustainable furniture can be created and produced in a co-creation process. The furniture industry should thus become significantly more flexible, transparent and sustainable. Following the "do-it-together" approach, a business ecosystem will be generated which creates added value not only for customers but also for designers, suppliers and manufacturing companies. In order to involve the customer even more actively in the design process and the production, the platform will provide access to a mix of digital and physical services and is linked to all other stakeholders in the value chain. To match the platform and the process to the needs, wishes and demands of the customer an anonymous survey with 300 participants was developed and conducted. By analyzing the survey, important factors were found for buying and for using furniture considering new technological inventions (e.g. 3D-printing or smart objects), sustainability of the products and the production process. Furthermore, the potential customer-group and their usage of the do-it-together process and additional activities can be tightened

Development of a Scalable Fabrication Concept for Sustainable, Programmable Shape‐Morphing Metamaterials

Programmable materials are a novel development, in which specialized production processes are used to introduce a framework of information capabilities into the inner structure of materials. Since the design and fabrication of programmable materials are still challenging, this aims to introduce a design and fabrication concept to pave the way toward industrial application. Herein, complex shape morphing has been implemented in the sense that the shape changes in response to external conditions, following a predefined program. First, the feasibility of a fabrication concept for uniform metamaterials with auxetic behavior is presented. A material with a predetermined nonuniform inner structure that deforms to a symmetrical shape has been developed and fabricated according to this concept. More complex behavior can be implemented by facilitating optimization methods to find inner structures according to a target shape. Lastly, an optimized and producible design for asymmetrical shape morphing is described to demonstrate the applicability of the approach

A symptom-related monitoring program following pulmonary embolism for the early detection of CTEPH: a prospective observational registry study

Background Chronic thromboembolic pulmonary hypertension (CTEPH) is a long-term complication following an acute pulmonary embolism (PE). It is frequently diagnosed at advanced stages which is concerning as delayed treatment has important implications for favourable clinical outcome. Performing a follow-up examination of patients diagnosed with acute PE regardless of persisting symptoms and using all available technical procedures would be both cost-intensive and possibly ineffective. Focusing diagnostic procedures therefore on only symptomatic patients may be a practical approach for detecting relevant CTEPH. This study aimed to evaluate if a follow-up program for patients with acute PE based on telephone monitoring of symptoms and further examination of only symptomatic patients could detect CTEPH. In addition, we investigated the role of cardiopulmonary exercise testing (CPET) as a diagnostic tool. Methods In a prospective cohort study all consecutive patients with newly diagnosed PE (n=170, 76 males, 94 females within 26 months) were recruited according to the inclusion and exclusion criteria. Patients were contacted via telephone and asked to answer standardized questions relating to symptoms. At the time of the final analysis 130 patients had been contacted. Symptomatic patients underwent a structured evaluation with echocardiography, CPET and complete work-up for CTEPH. Results 37.7%, 25.5% and 29.3% of the patients reported symptoms after three, six, and twelve months respectively. Subsequent clinical evaluation of these symptomatic patients saw 20.4%, 11.5% and 18.8% of patients at the respective three, six and twelve months time points having an echocardiography suggesting pulmonary hypertension (PH). CTEPH with pathological imaging and a mean pulmonary artery pressure (mPAP) ≥ 25 mm Hg at rest was confirmed in eight subjects. Three subjects with mismatch perfusion defects showed an exercise induced increase of PAP without increasing pulmonary artery occlusion pressure (PAOP). Two subjects with pulmonary hypertension at rest and one with an exercise induced increase of mPAP with normal PAOP showed perfusion defects without echocardiographic signs of PH but a suspicious CPET. Conclusion A follow-up program based on telephone monitoring of symptoms and further structured evaluation of symptomatic subjects can detect patients with CTEPH. CPET may serve as a complementary diagnostic tool

Luminescence encoding of polymer microbeads with organic dyes and semiconductor quantum dots during polymerization

Luminescence-encoded microbeads are important tools for many applications in the life and material sciences that utilize luminescence detection as well as multiplexing and barcoding strategies. The preparation of such beads often involves the staining of premanufactured beads with molecular luminophores using simple swelling procedures or surface functionalization with layer-by-layer (LbL) techniques. Alternatively, these luminophores are sterically incorporated during the polymerization reaction yielding the polymer beads. The favorable optical properties of semiconductor quantum dots (QDs), which present broadly excitable, size-tunable, narrow emission bands and low photobleaching sensitivity, triggered the preparation of beads stained with QDs. However, the colloidal nature and the surface chemistry of these QDs, which largely controls their luminescence properties, introduce new challenges to bead encoding that have been barely systematically assessed. To establish a straightforward approach for the bead encoding with QDs with minimized loss in luminescence, we systematically assessed the incorporation of oleic acid/oleylamine-stabilized CdSe/CdS-core/shell-QDs into 0.5–2.5 µm-sized polystyrene (PS) microspheres by a simple dispersion polymerization synthesis that was first optimized with the organic dye Nile Red. Parameters addressed for the preparation of luminophore-encoded beads include the use of a polymer-compatible ligand such as benzyldimethyloctadecylammonium chloride (OBDAC) for the QDs, and crosslinking to prevent luminophore leakage. The physico-chemical and optical properties of the resulting beads were investigated with electron microscopy, dynamic light scattering, optical spectroscopy, and fluorescence microscopy. Particle size distribution, fluorescence quantum yield of the encapsulated QDs, and QD leaking stability were used as measures for bead quality. The derived optimized bead encoding procedure enables the reproducible preparation of bright PS microbeads encoded with organic dyes as well as with CdSe/CdS-QDs. Although these beads show a reduced photoluminescence quantum yield compared to the initially very strongly luminescent QDs, with values of about 35%, their photoluminescence quantum yield is nevertheless still moderate

Der Rochlitzer Supervulkan: Vulkanosedimentäre Faziesanalyse und Geochemie des permischen Rochlitz-Ignimbrit-Komplexes und seiner distalen Äquivalente

Im Schatten der ausklingenden variszischen Gebirgsbildung erschütterten katastrophale Supervulkanausbrüche vor ca. 300 Millionen Jahren das Spätpaläozoikum Mitteleuropas. Östlich von Leipzig erstreckt sich auf einer Gesamtfläche von 2.000 km² (ca. 10 % der Fläche des Freistaates) der Nordsächsische Vulkanitkomplex, welcher mindestens zwei große Calderen beinhaltet: 1) das Wurzener und 2) das Rochlitzer Vulkansystem. Wobei die Gesteine des Rochlitzer Vulkansystems die größte Verbreitung finden. Ablagerungen dieser intrakontinentalen und großvolumigen Eruptionen dienten zahlreichen historischen Bauwerken als Baustoff. Redaktionsschluss: 27.04.202

Zwischen Schattendasein, Governance und Entrepreneurship - Eine empirische Bestandsaufnahme zum Professionalisierungsgrad des IT-Managements in deutschen Krankenhäusern

Bei der Umsetzung der digitalen Transformation bewegt sich das ITManagement in Krankenhäusern in einem Spannungsfeld aus historischkulturellen Vorbedingungen und den besonderen Herausforderungen wissensintensiver Expertenorganisation. Um zu untersuchen, wie professionell das ITManagement vor diesem Hintergrund ist, wurde in der vorliegenden Studie der Professionalisierungsgrad des IT-Managements als Beschreibungsgröße vorgeschlagen. Darüber hinaus wurden Ausprägungen der IT-Governance und des IT-Entrepreneurships als mögliche Determinanten des Professionalisierungsgrades konzeptionalisiert. Ein entsprechend aufgestelltes, hypothesengeleitetes Untersuchungsmodell wurde anhand der Daten von 164 CIOs deutscher Krankenhäuser überprüft. Die Ergebnisse der Studie deuten auf Professionalisierungspotenziale des IT-Managements im strategischen und evaluierenden Bereich hin. Etablierte Kommunikationskanäle zwischen CIO und Krankenhausleitung sowie eine ausgewiesene IT-Budgetverantwortungen wirkten sich positiv auf den Professionalisierungsgrad aus. Zudem Das agierte das ITManagement umso professioneller, je stärker der IT-Entrepreneurship auf organisatorischer und individueller Ebene ausgeprägt war. Die Ergebnisse können den theoretischen Erkenntnisstand über die Wirkungsweise von IT-Governance und IT-Entrepreneurship erweitern und auf ähnliche, wissensintensive Expertenorganisationen übertragen werden