This book presents the design of steel structures using finite element methods (FEM) according to the current state of the art in Germany and the rest of Europe. After a short introduction on the basics of the design, this book illustrates the FEM with a focus on internal forces, displacements, critical loads and modal shapes. Next to finite element procedures for linear calculations considering the stress states of normal force, biaxial bending and warping torsion, non-linear calculations and the stability cases of flexural buckling, lateral torsional buckling and plate buckling are concentrated on significantly. In this context, design procedures for stability according to the standard Eurocode 3 is introduced and discussed. In addition, important fundamental issues are covered, such as the determination of cross-section properties as well as the elastic and plastic cross-section resistance. Complementary, finite element procedures for cross sections are dealt with, which will have an increasing importance in future. This book has evolved within the teaching activities of the authors in the lecture Computer-oriented Design of Steel Structures on the Master?s Program Computational Engineering at the University of Bochum. It covers the total variety of demands needed to be discussed for the safe, economic and modern design of steel structures.
This book constitutes the refereed proceedings of the First International Workshop on Cooperative Information Agents - DAI Meets Databases, CIA-97, held in Kiel, Germany, in February 1997. The book opens with 6 invited full papers by internationally leading researchers surveying the state of the art in the area. The 16 revised full research papers presented were carefully selected during a highly competitive round of reviewing. The papers are organized in topical sections on databases and agent technology, agents for database search and knowledge discovery, communication and cooperation among information agents, and agent-based access to heterogeneous information sources.
Heterocycle synthesis is one of the largest areas of modern organic chemistry. Heterocycles have a broad range of applications including pharmaceuticals, agrochemicals and dyes, and are the core structure to around 90% of naturally-occurring molecules. Transition metal catalysts have become favoured in heterocycle synthesis, not least because of their low cost, but also due to their relatively low environmental toxicity and biocompatibility. This book presents an overview of the state-of-the-art in transition metal catalysis for heterocycle synthesis. Each metal is discussed in turn, presenting a comprehensive source of information on the use of zinc, iron, copper, cobalt, manganese, and nickel in a sustainable and economic manner. Referencing the latest primary literature, and authored by active researchers in the field, this book is a must-have resource for anyone wishing to undertake an economic and sustainable approach to heterocycle synthesis.
The subject matter of volume 2 of the 2-volumes-handbook focusses especially on rare sarcomas of the whole female genitalia. These entities include angiosarcoma, the different lipo- and rhabdomyosarcoma as well as newer entities like the PEComa. Furthermore, mixed mullerian tumors like the benign adenofibroma and the malignant adenosarcoma and carcinosarcoma are described in detail. The book provides a description at length of the epidemiology, etiology, pathological anatomy, prognosis, diagnosis, differential diagnosis, imaging and comprehensive therapy of each primary, relapsed, and metastasized tumor including surgery, chemo-, hormone- and radio- and targeted therapy. An own chapter is devoted to the problems of fertility and pregnancy in connection with all sarcomas, variants of leiomyoma, atypical smooth muscle tumors, disseminated peritoneal leiomyomatosis, benign metastasizing leiomyoma, intravenous leiomyomatosis and endometrial stromal tumors – endometrial stromal nodules, endometrial stromal tumor with sex cord-like elements (ESTSCLE), uterine tumor resembling ovarian sex-cord tumor (UTROSCT) -and all mixed tumors - of the female genitalia. The book aims to identify and provide diagnostic and therapeutic guidance. The listed tumor entities also constitute a particular diagnostic challenge for pathologists that contains numerous pitfalls and difficulties. This book, therefore, addresses gynecologists and pathologists in both clinical and private practice, but also surgeons and hemato-oncologists.
Business process modelling is referred to as a complex, time consuming, and error prone task. The correction and improvement of badly designed process models becomes increasingly expensive in the later phases of the process management life cycle. This thesis develops the principles of guided process modelling and provides a contribution towards simplifying process modelling activities. The general research question this thesis answers is what are the difficulties in the usage of process modelling tools and which methods, techniques, and tools can guide users in modelling processes to target the existing problems. The question is addressed by following a research methodology of design sciences. Amongst others, it includes a detailed analysis of the research problem, a definition of the objective, the design and development of solutions, and an evaluation of the developed concepts. In summary, the thesis presents innovative concepts to support modellers and provides a step towards end-user enablement in process modelling.
The complex interactions between the innate and adaptive immune systems function to recognize and clear pathogens or transformed cells, but inefficient interactions between these two systems can result in harmful immunologic responses including chronic infections and the development of cancer. Several hallmarks of dysfunctional adaptive immune responses often detected in tumors share specific features with ineffective immunity in chronic infections. The members of the micromilieu actively participate in the process of tumorigenesis or chronification of infection by modulating innate and adaptive immune system interactions leading e.g. to insufficient T cell responses. The best example is given by the acquisition of an “exhausted” state of cytotoxic CD8+ T cells (CTLs) responding to chronic infections or tumors that are associated with elevated expression of inhibitory receptors and impaired cytokine response. Targeting these major inhibitory pathways by immune checkpoint blockers represents a prime example of successful clinical translation of tumor-specific immunotherapies. Understanding the mechanisms behind (mal)adaptations of the immune system is crucial for achieving therapeutic benefits. The establishment and co-evolution of a dynamic microenvironment niche constituted by the recruitment of numerous cell types dampen immune responses and thus contribute to the development of neoplastic transformation as well as infection. Although there are examples of successful immunotherapeutic approaches (CAR-T cells, immune checkpoint inhibitors, or mRNA vaccination), a large percentage of patients with cancer or chronic infections still do not benefit from these therapies or develop severe immune-related adverse events. The reasons for these failures are not well understood. A possible explanation might be that current immunotherapies target predominantly the effector arm of the immune system by trying to reactivate dysfunctional T cells, but do not sufficiently address the influence of the innate immune system and the contributions of the tumor microenvironment (TME) niche. The main problem we would like to address in this special issue is how inappropriate function of the innate immune system affects adaptive immunity and contributes to inefficient anti-cancer immunity and chronification of infections. The central goal is to provide a more precise understanding of the various (common and novel) immune evasion mechanisms in cancers and in chronic infections to obtain a detailed map of common and disease-specific immune escape checkpoints. To that aim, we want to compile a wide array of interdisciplinary studies exploring a comparative and multi-layered analysis of mechanisms responsible for inefficient immune responses, including novel approaches i.e. multi-omics or epigenetic signaling. We would also like to combine studies from different fields, including basic and clinical immunology, oncology, and virology/microbiology. We welcome the submission of Original Research, Review, Mini-Review, Methods, Case report, and Perspective articles that cover, but are not limited to the following topics: • Convergent mechanisms supporting immune escape in preclinical models (tumors and chronic infections) • Convergent evasion mechanisms mediated by tumor-infiltrating suppressive cells (Treg, MDSC, macro-phages, soluble mediators, signaling, metabolism, ...) • Convergent immune evasion mechanisms mediated by chronic infection (viral or parasite) • Novel strategies to modulate the TME by direct or indirect targeting of immune suppressor cells. • Approaches to enhance persistence and resilience of anticancer T cells • Combinatorial therapeutic strategies (mRNA, antibodies, immune checkpoint blockers …) that target convergent immune evasion mechanisms Manuscripts consisting solely of bioinformatics or computational analysis of public genomic or transcriptomic databases which are not accompanied by robust and relevant validation (clinical cohort or biological validation in vitro or in vivo) are out of scope for this topic.
This research monograph discusses the close correlation between the magnetic and structural properties of thin films in the context of numerous examples of epitaxial metal films, while emphasis is laid on the stabilization of novel structures compared to the bulk material. Further options, possibilities, and limits for applications are given. Techniques for the characterization of thin films are addressed as well.
Designed to provide English readers of German literature the opportunity to familiarize themselves with both the established canon and newly emerging literatures that reflect the concerns of women and ethnic minorities, the Encyclopedia of German Literature includes more than 500 entries on writers, individual work, and topics essential to an understanding of this rich literary tradition. Drawing on the expertise of an international group of experts, the essays in the encyclopedia reflect developments of the latest scholarship in German literature, culture, and history and society. In addition to the essays, author entries include biographies and works lists; and works entries provide information about first editions, selected critical editions, and English-language translations. All entries conclude with a list of further readings.
The aim of the book is to help students become data scientists. Since this requires a series of courses over a considerable period of time, the book intends to accompany students from the beginning to an advanced understanding of the knowledge and skills that define a modern data scientist. The book presents a comprehensive overview of the mathematical foundations of the programming language R and of its applications to data science.
An invaluable resource for students of law, politics, international relations and technology as well as for diplomats and civil society actors, this publication demonstrates how the Council of Europe contributes to ensuring that everyone’s voice online can be heard. This is key to sustainable, human rights oriented and people-centred digitalisation. Human rights matter on the internet. Without freedom of expression, people cannot participate in everything that the information society has to offer. Yet online free speech is in danger. Between state laws, private rules and algorithms, full participation in the online communicative space faces many challenges. This publication explores the profound impact of the internet on free expression and how it can be effectively secured online. The second, updated edition of this introduction into the protection of freedom of expression online answers essential questions regarding the extent and limits of freedom of expression online and the role of social networks, courts, states and organisations in online communication spaces. In clear language, with vivid examples spanning two decades of internet law, the authors answer questions on freedom of expression in cyberspace. Addressing issues from the protection of bloggers to the right to access online information, the publication also shows the importance of the standard-setting, monitoring and promotion activities of international and non-governmental organisations and includes a chapter on relevant national practice. It pays special attention to the role of European human rights law and the Council of Europe as this region’s most important human rights organisation.
The novel finite element formulations fall into the category of geometrically exact Kirchhoff-Love beams. A prominent characteristic of this category is that the absence of shear deformation is strongly enforced by removing two degrees of freedom. Further, the corresponding beam theories exhibit not only translational but also rotational degrees of freedom and their configurations thus form a non-additive and non-commutative space. Sophisticated interpolation schemes are required that need to be tested not only for locking, spatial convergence behavior, and energy conservation, but also for observer invariance and path-independence. For the three novel beam element formulations all these properties are analytically and numerically studied and confirmed, if applicable. Two different rotation parameterization strategies are employed based on the well-known geodesic interpolation used in many Simo-Reissner beams and the lesser known split into the so-called \textit{smallest rotation} and a torsional part. Application of the former parameterization results in a mixed finite element formulation intrinsically free of locking phenomena. Additionally, the first geometrically exact Kirchhoff-Love beam element is presented, which strongly enforces inextensibility by removing another degree of freedom. Furthermore, the numerical efficiency of the new beam formulations is compared to other beam elements that allow for or suppress shear deformation. When modeling very slender beams, the new elements offer distinct numerical advantages. Standard molecular dynamics simulations, which are commonly used to study polymers, suffer from a lack of a careful mathematical basis and the use of an expensive explicit time integration scheme. To circumvent these shortcomings and to be able to simulate stretching experiments on relevant time scales, the problem is described by a stochastic partial differential equation, which can be solved using the finite element method with a backward Euler temporal discretization. In detail, the polymer is represented by a Kirchhoff-Love beam with a linear elastic constitutive model. Inertial and electrostatic forces are neglected. It is deformed by a distributed load mimicking collisions with molecules of the surrounding fluid. Naturally, this load heavily fluctuates over time and space and mean values need to be computed in a Monte Carlo manner. To vastly speed up the fitting process to experimental data in a Bayesian framework, a surrogate model based on a Gaussian process is set up, which directly computes the mean values for given material parameters. The uncertainties and correlations of the material parameters are studied and compared to the literature.
The leading reference on this topic has just gotten better. Building on the success of the previous two editions, all the chapters have been updated to reflect the latest developments in the field, and new chapters have been added on picolinic acids, oxathiapiprolin, flupyradifurone, and other topics. This third edition presents the most important active ingredients of modern agrochemicals, with one volume each for herbicides, fungicides, and insecticides. The international team of first-class authors from such renowned crop science companies as Bayer, Syngenta, Dow AgroSciences, DuPont (now Corteva Agriscience), and BASF, address all crucial aspects from the general chemistry and the mode of action to industrial-scale synthesis, as well as from the development of products and formulations to their application in the field. A comprehensive and invaluable source of timely information for all of those working in modern biology, including genetics, biochemistry and chemistry, and for those in modern crop protection science, whether governmental authorities, researchers in agrochemical companies, scientists at universities, conservationists, or managers in organizations and companies involved in improvements to agricultural production.
Readers will find that, refreshingly, this text presents in a vivid yet concise style the necessary statistical and mathematical background for financial engineers. The focus is both on fundamentals of mathematical finance and financial time series analysis and on applications to given problems of financial markets, making the book the ideal basis for lectures, seminars and crash courses on the topic. For the second edition the book has been updated and extensively revised. Several new topics have been included, such as a chapter on credit risk management.
By employing a combination of approaches from several disciplines the authors elucidate the principles of a variety of biomechanical systems that rely on frictional surfaces or adhesive secretions to attach parts of the body to one another or to attach organisms to a substrate. This account provides an excellent starting point for engineers and physicists working with biological systems and for biologists studying friction and adhesion. It will also serve as a valuable introduction for graduate students entering this interdisciplinary field of research.
Catering to the current interest in increasing the spectral efficiency of optical fiber networks by the deployment of high-order modulation formats, this monograph describes transmitters, receivers and performance of optical systems with high-order phase and quadrature amplitude modulation. In the first part of the book, the author discusses various transmitter implementation options as well as several receiver concepts based on direct and coherent detection, including designs of new structures. Hereby, both optical and electrical parts are considered, allowing the assessment of practicability and complexity. In the second part, a detailed characterization of optical fiber transmission systems is presented, regarding a wide range of modulation formats. It provides insight in the fundamental behavior of different formats with respect to relevant performance degradation effects and identifies the major trends in system performance.
In this book, a precise treatment of the experimental characterization of advanced composite materials using Digital Image Correlation (DIC) is presented. The text explains test methods, testing setup with 2D- and stereo-DIC, specimen preparation and patterning, testing analysis and data reduction schemes to determine and to compare mechanical properties, such as modulus, strength and fracture toughness of advanced composite materials. Sensitivity and uncertainty studies on the DIC calculated data and mechanical properties for a detailed engineering-based understanding are covered instead of idealized theories and sugarcoated results. The book provides students, instructors, researchers and engineers in industrial or government institutions, and practitioners working in the field of experimental/applied structural mechanics of materials a myriad of color figures from DIC measurements for better explanation, datasets of material properties serving as input parameters for analytical modelling, raw data and computer codes for data reduction, illustrative graphs for teaching purposes, practice exercises with solutions provided online and extensive references to the literature at the end of each stand-alone chapter.
Four leaders in the field of microwave circuit design share their newest insights into the latest aspects of the technology The third edition of Microwave Circuit Design Using Linear and Nonlinear Techniques delivers an insightful and complete analysis of microwave circuit design, from their intrinsic and circuit properties to circuit design techniques for maximizing performance in communication and radar systems. This new edition retains what remains relevant from previous editions of this celebrated book and adds brand-new content on CMOS technology, GaN, SiC, frequency range, and feedback power amplifiers in the millimeter range region. The third edition contains over 200 pages of new material. The distinguished engineers, academics, and authors emphasize the commercial applications in telecommunications and cover all aspects of transistor technology. Software tools for design and microwave circuits are included as an accompaniment to the book. In addition to information about small and large-signal amplifier design and power amplifier design, readers will benefit from the book's treatment of a wide variety of topics, like: An in-depth discussion of the foundations of RF and microwave systems, including Maxwell's equations, applications of the technology, analog and digital requirements, and elementary definitions A treatment of lumped and distributed elements, including a discussion of the parasitic effects on lumped elements Descriptions of active devices, including diodes, microwave transistors, heterojunction bipolar transistors, and microwave FET Two-port networks, including S-Parameters from SPICE analysis and the derivation of transducer power gain Perfect for microwave integrated circuit designers, the third edition of Microwave Circuit Design Using Linear and Nonlinear Techniques also has a place on the bookshelves of electrical engineering researchers and graduate students. It's comprehensive take on all aspects of transistors by world-renowned experts in the field places this book at the vanguard of microwave circuit design research.
The third edition of this successful textbook is a comprehensive, rigorous survey of the major topics in the field of behavioral economics. Building on the strengths of the second edition, it offers an up-to-date and critical examination of the latest literature, research, developments and debates in the field. Offering an inter-disciplinary approach, the authors incorporate psychology, evolutionary biology and neuroscience into the discussions. And, ultimately, they consider what it means to be 'rational', why we so often indulge in 'irrational' and self-harming behavior, and also why 'irrational' behavior can sometimes serve us well. A perfect book for economics students studying behavioural economics at higher undergraduate level or Master's level. This new edition features: - Extended material on heuristics and biases, and new material on neuroeconomics and its applications - A wealth of new topical case studies, such as voting behavior in Brexit and the Trump election and the current obesity epidemic - More examples and review questions to help cement understanding
Virtual Reality has the potential to provide descriptive and practical information for medical training and therapy while relieving the patient or the physician. Multimodal interactions between the user and the virtual environment facilitate the generation of high-fidelity sensory impressions, by using not only visual and auditory, but also kinesthetic, tactile, and even olfactory feedback modalities. On the basis of the existing physiological constraints, Virtual Reality in Medicine derives the technical requirements and design principles of multimodal input devices, displays, and rendering techniques. Resulting from a course taught by the authors, Virtual Reality in Medicine presents examples for surgical training, intra-operative augmentation, and rehabilitation that are already in use as well as those currently in development. It is well suited as introductory material for engineering and computer science students, as well as researchers who want to learn more about basic technologies in the area of virtual reality applied to medicine. It also provides a broad overview to non-engineering students as well as clinical users, who desire to learn more about the current state of the art and future applications of this technology.
A creative lifestyle is not a luxury, but a necessary elixir of life. Only with creativity can we overcome despair, hatred and violence, in the world and in ourselves. Using selected examples of exceptionally creative people, Rainer M. Holm-Hadulla encourages us to unleash our own creative and social potential. Readers become acquainted with Madonna and Amy Winehouse, John Lennon, Jim Morrison, and Mick Jagger. Before wandering through their lives and work in the interplay of constructive and destructive forces, they encounter the "Big Five of Creativity": talent, ability, motivation, resilience, favorable environments. The author has theoretically researched their interaction over decades, tested them in practice and drawn the conclusion: The creative transformation of human destructiveness is our chance to lead a fulfilled life in social responsibility.
Although electric vehicles (EVs) are theoretically capable of emissions-free driving, their market penetration is still pending, which is reflected in their low sales numbers. This is mainly due to three major barriers to the widespread adoption of these vehicles, with one of them being their limited average driving distance. Although the limited range of these cars would theoretically be sufficient to match the usage patterns of most drivers, they are generally unwilling to accept it. In this regard, users often report serious concerns about not reaching their planned destinations due to battery depletion, which is commonly referred to as range anxiety. Within this cumulative dissertation, four research questions were derived, aiming to investigate measures that mitigate range anxiety and thus positively affect the attitude toward using EVs. To answer these research questions, six studies were conducted. The insights gained from analyzing the data provide researchers with an in-depth knowledge for investigating the influence of information systems on range anxiety. In addition, practitioners find decision support for addressing the phenomenon of range anxiety in implementing and designing information systems.
This book reviews interdisciplinary work on the mental processing of syntax and morphology. It focuses on the fundamental questions at the centre of this research, for example whether language processing proceeds in a serial or a parallel manner; which areas of the brain support the processing of syntactic and morphological information; whether there are neurophysiological correlates of language processing; and the degree to which neurolinguistic findings on syntactic andmorphological processing are consistent with theoretical conceptions of syntax and morphology. The authors describe the outcomes of methods in neurophysiology (for example, functional magnetic resonance imaging), behavioural psycholinguistics, and neuropsychological lesion studies, and provide briefintroductions to the methods themselves. They extend basic findings at the word and sentence level by considering how the mental processing of syntax and morphology relates to prosody, discourse, semantics, and world knowledge. They have divided the work into four parts concerned with word structure, sentence structure, processing syntax and morphology at the interfaces, and a comparison of different models of syntactic and morphological processing in the neurophysiological domain. The book isdirected at graduate students and researchers in theoretical linguistics, psycho- and neurolinguistics, neurophysiology, and psychology.
The subject matter of volume 1 of the 2-volumes-handbook focusses on leiomyosarcoma, low-grade and high-grade endometrial sarcoma and undifferentiated uterine sarcoma of the whole female genitalia. A separate extensive chapter is devoted to the variants of leiomyoma (angio-, lipo-, cotyledonoid, cellular, mitotically active, epithelioid and myxoid leiomyoma, leiomyoma with bizarre nuclei), atypical smooth muscle tumors (smooth muscle tumors with uncertain malignant potential), and disseminated peritoneal leiomyomatosis, benign metastasizing leiomyoma, and intravenous leiomyomatosis. Furthermore, endometrial stromal tumors – endometrial stromal nodules, endometrial stromal tumor with sex cord-like elements (ESTSCLE), uterine tumor resembling ovarian sex-cord tumor (UTROSCT) - and similar tumors are described in detail. The book provides a description at length of the epidemiology, etiology, pathological anatomy, prognosis, diagnosis, differential diagnosis, imaging and comprehensive therapy of each primary, relapsed, and metastasized tumor including surgery, chemo-, hormone- and radio- and targeted therapy. Another chapter is devoted to the prevention of subjecting sarcomas to inadequate surgical therapeutic measures under the assumed diagnosis of leiomyoma, and includes a diagnostic-therapeutic flowchart with a diagnostic score. The book aims to identify and provide diagnostic and therapeutic guidance. The listed tumor entities also constitute a particular diagnostic challenge for pathologists that contains numerous pitfalls and difficulties. This book, therefore, addresses gynecologists and pathologists in both clinical and private practice, but also surgeons and hemato-oncologists.
Production planning in fresh food industries is a challenging task. Although modern Advanced Planning and Scheduling (APS) systems could provide significant support, APS implementation numbers in these industries remain low. Therefore, based on an in-depth analysis of three sample fresh food industries (dairy, fresh and processed meat), the author evaluates what APS systems should offer in order to effectively support production planning and how the leading systems currently handle the most distinguishing characteristic of fresh food industries, the short product shelf life. Starting from the identified weaknesses, customized software solutions for each of the sample industries are proposed that allow to optimize the production of fresh foods with respect to shelf life. The book thereby offers valuable insights not only to researchers but also to software providers of APS systems and professionals from fresh food industries.
For ensuring a software system's security, it is vital to keep up with changing security precautions, attacks, and mitigations. Although model-based development enables addressing security already at design-time, design models are often inconsistent with the implementation or among themselves. An additional burden are variants of software systems. To ensure security in this context, we present an approach based on continuous automated change propagation, allowing security experts to specify security requirements on the most suitable system representation. We automatically check all system representations against these requirements and provide security-preserving refactorings for preserving security compliance. For both, we show the application to variant-rich software systems. To support legacy systems, we allow to reverse-engineer variability-aware UML models and semi-automatically map existing design models to the implementation. Besides evaluations of the individual contributions, we demonstrate the approach in two open-source case studies, the iTrust electronics health records system and the Eclipse Secure Storage.
The decision to diversify lies at the core of corporate strategy and is one of the most important decisions for top management. Matthias Knecht introduces a new perspective on corporate diversification that extends the academic discussion and reveals substantial new insights with regards to one of the most pressing questions in strategic management: what makes a diversification strategy successful? The author introduces the dynamism of industries as the dominant force in the firm’s environment that influences the organization on all levels. Due to strategic, organizational, and managerial similarities of businesses competing in similar dynamic environments, synergistic benefits and superior economic performance can be realized through the combination of dynamic-related businesses in the corporate portfolio. This study provides a quantitative, multidimensional operationalization of industry dynamism and an in-depth assessment of the dynamism of a wide range of industries. At the core of the study lies the investigation of the performance impact of dynamic-related diversification strategies. The results provide new insights into successful portfolio construction strategies in the face of today’s dynamic environments.
Poly(ethylene terephthalate) is one of the most widely used polymers in packaging industry, due to its high mechanical strength, chemical resistance, and barrier functions. However, its processing is determined by degradation and low viscosity. In particular, foaming and film blowing is restricted by the linear structure of the molecule and low melt strength. The stability of three linear commercial PET grades produced by different synthesis routes with different molar masses is analyzed in regards of processing at industrial scale. Subsequently, reactive processing with three multi-functional chain extenders (pyromellitic dianhydride, PMDA, tetraglycidyl diamino diphenyl methane, TGDDM, and triphenyl phosphite, TPP) is conducted to create large and long-chain branched (LCB) molecules. The mechanical and molecular properties in melt state are analyzed by linear and non-linear viscoelastic rheology, modeling by the molecular stress function (MSF) theory and size-exclusion chromatography (SEC) with light scattering measurements. Thermal stability measurements in the linear viscoelastic regime revealed degradation and a reduction of the storage modulus in air atmosphere, and, besides thermal degradation, an enhancement of the modulus in nitrogen atmosphere, due to polycondensation [Kruse et al., 2013]. Fitting by an exponential function leads to the reconstruction of the initial state of the sample at zero-loading time and to a time constant, which reveals clear relations between stability and molar mass for all three PET grades in both atmospheres. High molar mass PET is more stable in nitrogen and less stable in air environment, and vice versa, depending on OH end group concentration and synthesis route. The analysis by means of time-resolved mechanical spectroscopy allows the observations of moduli and complex viscosity at a fixed time, a wide range of angular frequencies, and at different atmospheres, and revealed: (i) a plasticizer effect induced by small molecules from thermal and thermo-oxidative degradation, (ii) cross-linking leading to yield stress, (iii) diffusion influencing polycondensation reaction, (iv) slipping due to deposition of side products, and (v) an enhanced shear thinning regime [Kruse and Wagner, 2016]. The extrusion of neat PET with a twin-screw extruder at industrial scale leads to strong reduction of viscosity mainly due to shearing. The impact of thermo-oxidative degradation is comparably small. The reactive processing of the three PET grades with the three chain extenders leads to the conclusion that the tri-functional TPP is not a useful chain extender due to rapid degradation and toxicity. The two tetra-functional chain extenders, PMDA and the epoxy-based TGDDM, lead to strong viscosity increase, increasing strain hardening effect, and increasing thermal stability with increasing chain extender concentration as confirmed by loss- and storage modulus, phase angle, activation energy of flow, and elongational viscosity. The MSF model predictions show good agreement with data measured, and allowed a quantitative analysis of the branching structure and of the stretch of the molecules by both non-linear MSF parameters. In comparison to the high molar mass PET with an apparent comb-like structure at high PMDA concentrations, the two initially low molar mass grades show a higher molar mass after processing with PMDA and seem to have a tree-like structure, which can be explained by the hydroxyl end group concentration of these two PET grades. The extensive use of TGDDM leads to a hyperbranched and gel-like structure. The fracture analysis from uniaxial elongation experiments reveals a limiting stress value for high PMDA concentrations and a limiting strain value for high TGDDM concentrations due to formation of a covalent network. The molecular analysis by SEC with triple detection of the high molar mass PET, which was reacted with PMDA and TGDDM, shows a strong increase of the average molar masses, polydispersity, radius of gyration, and hydrodynamic radius and confirms the molar mass increase observed by the rheological measurements. The branching was confirmed by a decreasing Mark-Houwink exponent with increasing chain extender concentration. Further, the analysis of the contraction of the molecule revealed a more star-like structure at low concentrations for both chain extenders. With increasing concentration, the structure changed to more comb-like for PMDA and random tree-like or hyperbranched for TGDDM as was also observed by non-linear viscoelastic measurements. PMDA revealed to be an excellent coupling agent which induces reproducibly either a star-like, comb-like, or tree-like structures depending on the concentration of coupling agent added and the hydroxyl concentration of the PET employed. Polyethylenterephthalat (PET) zeichnet sich durch hervorragende mechanische Eigenschaften, sowie chemische Beständigkeit und Barriereeigenschaften aus und findet insbesondere in der Verpackungsindustrie Verwendung. Die Neigung zur Degradation und die wegen der linearen Kettenmoleküle geringe Viskosität schränken jedoch die Verarbeitbarkeit von PET wie beispielsweise das Schäumen und Folienblasen erheblich ein. In der vorliegenden Arbeit wird der Einfluss der thermischen Stabilität während der Verarbeitung von drei linearen industriellen PET-Typen untersucht, die sich durch Molmasse und Herstellungsverfahren unterscheiden. Des Weiteren wird langkettenverzweigtes PET (LCBPET) durch reaktive Verarbeitung mit drei verschiedenen multifunktionalen Kettenverlängerern, Pyromellitsäuredianhydrid (PMDA), Tetra- glycidyl-Diamino-Diphenyl-Methan (TGDDM) und Triphenylphosphit (TPP), hergestellt und charakterisiert. Durch die experimentelle Bestimmung der linearen und nichtlinearen rheologischen Eigenschaften der Schmelze und ihre Beschreibung mit Hilfe des sogenannten "Molecular Stress Function" (MSF) Modells gelingt eine quantitative Analyse des Materialverhaltens. Die molekulare Analyse wird zusätzlich durch die Ergebnisse von Gelpermeationschromatographie (GPC bzw. SEC) in Verbindung mit Lichtstreumessung gestützt. Die Untersuchungen der thermischen Stabilität von linearem PET im linear-viskoelastischen Bereich zeigen einen abnehmenden Speichermodul und somit ein thermo-oxidatives Degradationsverhalten in Luftatmosphäre. In inerter Stickstoffatmosphäre tritt hingegen nur thermische Degradation auf, gleichzeitig führt jedoch eine Polykondensationsreaktion zu einem Anstiegen des Moduls [Kruse et al., 2013]. Mit einem exponentiellen Regressionsansatz kann der anfängliche Zustand des Moduls in beiden Atmosphären zum Zeitpunkt Null, der dem Einbringen der Probe in das Rheometer entspricht, rekonstruiert werden. Die sich aus diesem Ansatz ergebende Zeitkonstante erlaubt es, quantitative Zusammenhänge zwischen der thermischen Stabilität der drei PET-Sorten und deren Molmasse sowie dem Herstellungsverfahren der PET-Typen aufzuzeigen. So weist hochmolekulares PET eine höhere Stabilität in Stickstoff und eine geringere Stabilität in Luft auf und umgekehrt. Hauptursache für dieses Verhalten ist die unterschiedliche Konzentration an Hydroxylendgruppen, die je nach Molmasse und Herstellungsmethode der jeweiligen PET-Typen variiert. Mit Hilfe der "Time-Resolved Mechnical Sprectroscopy" konnte die sich ändernde Viskosität über ein weites Frequenzspektrum und zu einer beliebigen Messzeit in beiden Atmosphären bestimmt werden. Wesentliche Ergebnisse dieser Untersuchung sind der Nachweis des Auftretens von (i) einem Weichmachereffekt bedingt durch die thermische und thermo-oxidative Degradation und den daraus resultierenden Oligomeren, (ii) dreidimensionaler Vernetzung mit der Ausbildung einer Fließgrenze, (iii) Diffusionsprozessen, die Einfluss auf die Polykondensationsreaktion haben, (iv) Wandgleiten, bedingt durch die Ablagerung von Nebenprodukten auf den Platten des Rheometers und (v) einem verbreiterten Scherverdünnungbereich [Kruse and Wagner, 2016]. Die Extrusion von linearem PET mit einem Doppelschneckenextruder unter industriellen Bedingungen führt zu einer starken Abnahme der Viskosität, die hauptsächlich durch Scherung und weniger durch thermo-oxidativen Abbau verursacht wird. Bei der reaktiven Verarbeitung der drei PET-Typen mit den drei verschiedenen Kettenverlängerern erwies sich das dreifunktionale TPP auf Grund von Toxizität und Lagerinstabilitäten als unbrauchbar. Die Verarbeitung der beiden vierfunktionalen Kettenverlängerer, PMDA und das epoxidhaltige TGDDM, führt zu erhöhter Viskosität, erhöhter Dehnverfestigung und erhöhter thermischer Stabilität mit zunehmender Konzentration des jeweiligen Kettenverlängerers. Das beschriebene Verhalten zeigt sich sowohl am Speicher- und Verlustmodul und dem daraus abgeleiteten Verlustwinkel, als auch an der Fließaktivierungsenergie und der Dehnviskosität. Dabei lassen sich die gemessenen Dehnviskositäten sehr präzise mit dem MSF-Modell beschreiben und die beiden nichtlinearen Modelparameter, β und f_max^2 ermöglichen eine quantitative Analyse der Verzweigungsstruktur und der Molekülstreckung. So zeigt die Modifiziereng von hohen PMDA-Konzentrationen und dem hochmolekularen PET eine mehr kammartige Struktur im Vergleich zu den beiden niedermolekularen PET-Typen, die eine baumartige Molekülstruktur und eine höhere Molmasse nach der reaktiven Extrusion aufweisen. Beide Effekte können mit der höheren OH-Endgruppenkonzentration der beiden niedermolekularen PET-Typen erklärt werden. Zu hohe Zusätze von TGDDM führen zu einem hochverzweigten und gelartigen Polymer. Das Bruchverhalten bei der uniaxialen Dehnung von mit einem hohen Zusatz von PMDA hergestellten langkettenverzweigten PET wird von einer limitierenden Bruchspannung bestimmt. Demgegenüber bestimmt eine maximale Dehnung das Bruchverhalten des mit einem hohen TGDDM-Zusatz hergestellten LCB-PET, verursacht durch ein kovalent gebundenes Polymernetzwerk. Die GPC Messungen mit drei Detektoren wurden an LCB-PET durchgeführt, das auf Basis der hochmolekularen PET-Type hergestellt wurde. Die molekulare Analyse der mit PMDA und TGDDM modifizierten Proben zeigt eine deutliche Zunahme der mittleren Molmassen, Molmassenverteilungsbreite, des Gyrationsradius und des hydrodynamischen Radius und bestätigt somit die rheologischen Ergebnisse. Das Auftreten von Verzweigungen wird außerdem durch den abnehmenden Mark-Houwink-Exponenten bei zunehmender Additivkonzentration verdeutlicht. Eine genauere Betrachtung weist auf eine sternartige Molekülstruktur bei geringer Zugabe beider Kettenverlängerer hin. Bei erhöhter Zugabe hingegen tritt eine kammartige Struktur bei PMDA und eine baumartige oder hochverzweigte Struktur bei TGDDM auf, wie auch aus den nichtlinearen viskoelastischen Messungen zu schließen ist. Insbesondere PMDA erweist sich als hervorragender Kettenverlängerer, der bei reaktiver Extrusion reproduzierbar eine sternartige, kammartige oder baumartige Molekülstruktur in Abhängigkeit von der verwendeten PET-Type und der PMDA-Konzentration ermöglicht und so das Verarbeitungsspektrum von PET auf neue Anwendungsgebiete erweitert.
This comprehensive introduction to computational network theory as a branch of network theory builds on the understanding that such networks are a tool to derive or verify hypotheses by applying computational techniques to large scale network data. The highly experienced team of editors and high-profile authors from around the world present and explain a number of methods that are representative of computational network theory, derived from graph theory, as well as computational and statistical techniques. With its coherent structure and homogenous style, this reference is equally suitable for courses on computational networks.
The first war between China and Japan in 1894/95 was one of the most fateful events, not only in modern Japanese and Chinese history, but in international history as well. The war and subsequent events catapulted Japan on its trajectory toward temporary hegemony in East Asia, whereas China entered a long period of domestic unrest and foreign intervention. Repercussions of these developments can be still felt, especially in the mutual perceptions of Chinese and Japanese people today. However, despite considerable scholarship on Sino-Japanese relations, the perplexing question remains how the Japanese attitude exactly changed after the triumphant victory in 1895 over its former role model and competitor. This book examines the transformation of Japan’s attitude toward China up to the time of the Russo-Japanese War (1904/5), when the psychological framework within which future Chinese-Japanese relations worked reached its erstwhile completion. It shows the transformation process through a close reading of sources, a large number of which is introduced to the scholarly discussion for the first time. Zachmann demonstrates how modern Sino-Japanese attitudes were shaped by a multitude of factors, domestic and international, and, in turn, informed Japan’s course in international politics. Winner of the JaDe Prize 2010 awarded by the German Foundation for the Promotion of Japanese-German Culture and Science Relations
International interest in Holocaust education has reached new heights in recent years. This historic event has long been central to cultures of remembrance in those countries where the genocide of the Jewish people occurred. But other parts of the world have now begun to recognize the history of the Holocaust as an effective means to teach about mass violence and to promote human rights and civic duty, testifying to the emergence of this pivotal historical event as a universal frame of reference. In this new, globalized context, how is the Holocaust represented and taught? How do teachers handle this excessively complex and emotionally loaded subject in fast-changing multicultural European societies still haunted by the crimes perpetrated by the Nazis and their collaborators? Why and how is it taught in other areas of the world that have only little if any connection with the history of the Jewish people? Holocaust Education in a Global Context will explore these questions."--page 10.
Supply chain management helped companies to manage volumes, fulfil customer demand and optimize costs in production and distribution. Specifically, chemical industry companies with high complexity in production and distribution used supply chain management to steer their operations. Confronted with globalization and increasing raw material and sales price volatility, optimizing supply chain costs is no longer sufficient to ensure the overall profitability of the business. Value chain management takes supply chain management to the next level by integrating all volume and value decisions from sales to procurement. The book presents the value chain management concept and demonstrates how it is applied in a global value chain planning model for commodities in the chemical industry. A comprehensive industry case study illustrates the effects of decision making integration, e.g. the influence of raw material prices or exchange rates on optimal sales, production, distribution and procurement plans as well as overall company profitability.
The book provides readers with an overview of the unique features of German business and enterprise law and an in-depth analysis of the organs of governance of German public limited companies (general meeting, management board, supervisory board). In addition, approaches for reforms required at the international level are also suggested and discussed, including, among others, the unique interplay and dynamics of the German two-tier board model with the system of codetermination, referring to the arrangement of employees sitting on the supervisory boards of German public limited companies and private companies employing more than 500 employees; also covered are significant recent legal developments in Europe.The book highlights the core function of valuation and financial reporting at the international, European and German levels, with accounting as the documentary proof of good corporate governance. Corporate governance encompasses the free enterprise system, which is treated comprehensively in this book from a German perspective. This distinguishes the book from other books written in English in this subject area, not only because of the comprehensive way it covers German corporate law and corporate governance, but also because of the fact that it provides international and European perspectives on these important topics.The book is addressed to researchers, practitioners and basically anyone with an interest in the complex, but intriguing areas of corporate law and corporate governance.
This volume gives the proceedings of the ninth Symposium on Theoretical Aspects of Computer Science (STACS). This annual symposium is held alternately in France and Germany and is organized jointly by the Special Interest Group for Fundamental Computer Science of the Association Francaise des Sciences et Technologies de l'Information et des Syst mes (AFCET) and the Special Interest Group for Theoretical Computer Science of the Gesellschaft f}r Informatik (GI). The volume includes three invited lectures and sections on parallel algorithms, logic and semantics, computational geometry, automata and languages, structural complexity, computational geometry and learning theory, complexity and communication, distributed systems, complexity, algorithms, cryptography, VLSI, words and rewriting, and systems.
The book develops a comprehensive understanding of the surface impedance of the oxide high-temperature superconductors in comparison with the conventional superconductor Nb3Sn. Linear and nonlinear microwave responses are treated separately, both in terms of models, theories or numerical approaches and in terms of experimental results. The theoretical treatment connects fundamental aspects of superconductivity to the specific high-frequency properties. The experimental data review the state of the art, as reported by many international groups. The book describes further the main features of appropriate preparation, handling, mounting, and refrigeration techniques, and finally discusses possible applications in passive and active microwave devices.
Corporate valuation using multiples is one of the most popular corporate valuation approaches. In this book, the different steps of this valuation approach such as the selection of comparable companies or the choice of the reference variables are discussed. Then, the circumstances required for a sound valuation (e.g., the degree of efficiency of the equity market) are described. Additionally, the book gives insight on how the state of the industry and/or the company has an impact on the proper choice of the reference variables. Finally, it is shown how multi-factor models can enrich the universe of valuation models. While always maintaining the academic rigor, the author addresses practice-relevant topics and delivers hands-on solutions for typical valuation problems.
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