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  • av Patryk Zapadka
    670,-

    Im Zeitalter der Digitalisierung müssen Unternehmen ihre Prozesse, Produkte und Geschäftsmodelle anpassen, um ihre Innovations- sowie Wettbewerbsfähigkeit aufrecht zu erhalten. Aufgrund dessen müssen Unternehmen ihre bestehenden Kompetenzen erneuern, indem sie neues Wissen aus der digitalen Sphäre wertstiftend integrieren. Dies stellt jedoch eine erhebliche Herausforderung dar, insbesondere für etablierte Unternehmen, da die konvergente und generative Natur der digitalen Innovation nicht nur den Prozess der Wissensintegration dynamischer macht, sondern auch die Vielfalt und Menge des Wissens erhöht, das über die Unternehmensgrenzen hinweg integriert werden muss. Um diese Herausforderung näher zu beleuchten und Lösungsansätze zu evaluieren, wurden vier Studien durchgeführt und in dieser kumulativen Dissertation zusammengestellt. Diese Studien geben Einblicke in die Besonderheiten der Wissensintegration im Kontext digitaler Innovationen und fördern das Verständnis dafür, wie etablierte Unternehmen die damit verbundenen Herausforderungen bewältigen können. Dabei wird insbesondere der Einsatz von Grenzressourcen, wie bspw. Programmierschnittstellen (APIs), untersucht, da sie einen wesentlichen Mechanismus zur Skalierung der Wissensintegration in digital(isierenden) Geschäftsökosystemen darstellen.

  • av Michael Altgen
    533,-

    Various thermal wood modification technologies have been developed in Europe during the past decades that differ notably in the process conditions applied. However, the changes in wood properties by thermal modification, the underlying modes of action and their link to the process conditions are still not fully understood. This thesis investigates the influence of different process conditions in open and closed reactor systems on the resulting properties of thermally modified wood. In closed reactor systems, elevated water vapor pressure accelerates the thermal degradation of wood polymers and results in high mass loss levels even at mild treatment temperatures. However, in addition to the loss in wood mass, a strong influence of drying and softening of wood at elevated temperatures as well as an increased cell wall matrix stiffness by modification of the lignin carbohydrate complex under dry heat conditions influences the wood properties, i.e. water sorption. For wood thermally modified in open reactor systems at different peak temperatures and durations, the surface performance is investigated with regard to the susceptibility to surface cracking, photodegradation and coatability. The results provide explanations why the performance of thermally modified wood in exterior applications does not always meet the expectations derived from its enhanced resistance against decay fungi.

  • av Anne Thomas
    740,-

    Actuaries working in claims reserving are often faced, among others, with the following two tasks: the prediction of future outstanding loss liabilities, as well as the quantification of their risk. Within claims reserving there exist various methods in which vagueness and subjective judgement is often not considered. A formal approach is given e.g. by fuzzy set theory.Besides an overview of applications of fuzzy set theory in claims reserving the author presents three ways of how subjective assessment can be implemented in the chain-ladder as well as the Bornhuetter Ferguson method.

  • av Bernhard Freyer & Erik Tielkes
    1 000,-

    The theme of 2016 is ¿Solidarity in a competing world ¿ fair use of resources¿. While on the one hand, one part of the world is profiting from natural resources, the other part of the world is suffering with hunger, malnutrition, human diseases, low income, violence and lately is also challenged through climate change. There is need to rethink and engage in a fair share of all resources between the continents and nations. This includes huge engagement into the management of natural resources to solve the long list of environmental threats expressed through ongoing erosion, loss of soil fertility and loss of biodiversity, and topped by climate change having strong impact on the productivity in agriculture, fishery and forestry, and the use and quality of water and of energy in the South.

  • av Ibraheem Al Naib
    250,-

    One of the most important developing fields is that of digital communication. This is due to the demand for an increasingly higher speed in the exchange of information, which is presently growing at an exponential rate. In fact, considerable efforts have been made towards the realization of low-power miniaturized radio frequency components. However, issues related to design and fabrication of efficient, ultra-compact, and easily integrate-able microwave components appear to be challenging. Many unit cells are needed in order to achieve high efficiency components, such as filters and couplers, whose dimensions are comparable or larger than a single wavelength cycle. However, during the past decade, metamaterials, a novel class of artificial materials, have become a field of active research in physics and engineering. These metamaterials offer unique electrodynamic properties, which are neither available in any natural material nor observable in the materials presently used in state-of-the-art technology. Furthermore, a metamaterials unit cell is much smaller than the wavelength of reference.The main objective of my dissertation was to design and realize new resonator structures to meet the challenges of simple, high performance, and miniaturized microwave circuits as well as terahertz components for filtering and sensing applications. First of all, I suggested a series of novel structures for filter applications. They consist of only a single metal layer, an approach which I suggested for the first time worldwide. Later on, I realized more advanced miniaturized resonators based on the same idea.

  • av Sarah Anyang Agbor
    640,-

    Sarah ANYANG AGBOR¿S text is a conceptual, historical and functionalexamination of Commonwealth Literature. The text comes acrossas a nice way to review some of the essential conceptual andhistorical development of Commonwealth literature. This text will beof special interest for students in Commonwealth studies.The workresponds to two ways of looking at Commonwealth literature. The fi rstis a conceptual defi nition, historical development and diversifi cationof Commnwealth Literature. The other is to investigate through sociologicalcriticism the various ways Commonwealth Literature dissents .This comparative analysis which is not limited to authors and regionsbut extends to the erstwhile and the contemporary, offers invaluableinsights into the longstanding debates surrounding the concept ofCommonwealth Literature in particular and draws conclusions thatdo not pretend to close the debate but rather articulate the discursivenature of Commonwealth Literature and the ambivalence of its ¿defi -ning¿ parameters.

  • av Achim Althaus
    390,-

    Dynamic capabilities describe the firms' capacity to adapt their resources with regard to external shifts in order to maintain or to even enlarge competitive advantage. In this essay the author pursues three research objectives regarding dynamic capabilities. First, based on a literature review the author states that no appropriate dynamic capability concept exists that enables an empirical investigation of dynamic capabilities across industries, however, argues that such an investigation is possible, and outlines a first step to do so. The second research objective is focused on the value of dynamic capabilities. Using real option knowledge the author is able to outline a simple mathematical model. The results show that the value of a firm is not only given by the expected value, generated by the firm's resources in place, but also by the firm's options to react to environmental changes. Besides other externally given factors - like market development - the application of dynamic capabilities in terms of time has consequences on the expected firm value. The third research objective deals with the basic challenge of ambidextrous firms to achieve an optimal balance of exploitative and explorative activities with regard to market developments. Again, using real option knowledge the author is able to demonstrate that there exist defined points in time until when to maintain, stress, taper off and finally stop exploitative and explorative activities. A further development of the model even enables the prediction of the value maximizing points in time.

  • av Arron A. Tchouka Singhe
    530,-

    Injection into geological formations is seen by many as a short to medium term measure to reduce emissions of CO2 to the environment and as such to slowdown the pace of global warming. The injection process requires that the fluid flows effectively into the host formation. To this end it is very important to accurately predict the pressure and temperature of the fluid along the well and especially at the bottom of the hole. In the present dissertation a rigorous procedure to estimate fluid pressure and temperature along CO2 injection wells has been developed based on analytical modeling. The procedure accommodates wellbores of varying diameter, varying deviation angles, non-uniform tubing strings and layered formations with different thermal properties and varying geothermal gradients.To test the models, computer codes have been written with Visual Basic.Net language on the Microsoft Visual Studio Platform. The codes are encapsulated in a user-friendly Graphical User Interface.The simulated results are compared with field observed data from a shallow aquifer injection vertical well in Germany (Ketzin) and that from a relatively deeper offshore aquifer injection slanted well in Norway (Snøhvit). The maximum deviation is around 2% for pressure and around 10% for temperature.

  • av Daouda Traoré
    880,-

    Ce livre estune contribution àla description dusenär (langue senufo parlée au Burkina Faso) et àl¿analyse des traits de l¿influence du jula véhiculaire (du Burkina Faso) sur le senar. L¿analyse descriptive du senär, objet de la première partie du livre, a été menée à travers ses principaux paliers que sont la phonologie, la morphologie et la syntaxe. Le chapitre sur la phonologie inclutnon seulement la phonologie de surface, maisaussi certains phénomènes morphophonologiquestels que les alternances consonantiques, la longueur vocalique, l¿harmonie vocalique, la formation des diphtongues, etc. Au titre de la morphologie, les points suivants ont été abordés: le système nominal, le système verbal et d¿autres catégories morphologiques comme les adverbes, les adpositions, les idéophones et les interjections. Quant à l¿étude syntaxique, elle a fait l¿objet de quatre grands points : la phrase simple, la phrase complexe,la construction sérielle et la construction consécutive. La deuxième partie du livre, consacrée à l¿analyse des discours des locuteurs du senär, est constituée de quatre chapitres. Le chapitre introductif de cette partie restitue les résultats d¿une enquête sociolinguistique préliminaire, menée à travers des fiches d¿enquêtes. Les trois autres chapitres ont porté sur l¿analyse des interviews, en vue de relever les traits réels de l¿influence du jula, tant sur les plans phonétique/phonologique, grammatical que lexico-sémantique.This book is divided into two major parts:The first part describes the Senar language in respect of its phonology and aspects of its grammar.The phonological aspect focuses on one hand on the phonology of surface. On the other hand, it examines some morphophonological phenomena as consonantal alternations, vocalic length, vocalic harmony, status of diphthongs, etc. The morphological analysis focuses on nouns, noun classes, pronouns, verbs, adverbs, numerals, interjections and modification. As for the syntactical analysis, it studies successively four major aspects: the simple sentence, the complex sentence, serial constructions and the consecutive constructions.The second part of the thesis consists of four chapters. The introductory chapter presents the results of the preliminary sociolinguistic survey, conducted with thirty Senar speakers through questionnaires. The three other chapters of this part bear on the analysis of the interviews by exploring the influences of Jula on Senar as concerns phonetic/phonological, grammatical and lexico-semantic aspects.

  • av Jelena Jenter
    310,-

    Bis(phosphinimino)methanide rare earth metal bisborohydrides, as illustrated in Scheme I, were successfully synthesized by salt metathesis reactions of [K{CH(PPh2NSiMe3)2}] with [Ln(BH4)3(THF)n] (Ln = Sc (n = 2); Ln = La, Nd, Lu (n = 3)) or in the case of yttrium by the reaction of [{(Me3SiNPPh2)2CH}YCl2]2 with NaBH4. Interestingly, the BH4- anions are?3-coordinated in the solid state structures of 3, 4, 6 and 7, while for the scandium complex 5 two different conformational polymorphs were identified, in which either both BH4- groups are ?3-coordinated or one BH4- anion shows an ?2-coordination mode. Furthermore, complexes 3, 6 and 7 showed high activities in the ring-opening polymerization (ROP) ofe-caprolactone (CL). At 0 °C, the molar mass distribution reached the narrowest values ever obtained for the ROP of CL initiated by a rare earth metal borohydride species.

  • av Tina Beuchelt
    466,-

    Organic and Fairtrade certified coffees have become very popular among socially, environmentally and health conscious consumers in recent years. As consumers pay higher prices for these certified coffees, it is commonly assumed that, compared to conventional coffee, better producer prices are paid and that higher shares of the added value in consuming countries trickle down to the producers. Coffee certifications are thus supposed to benefit the coffee producers. Coffee is an important export good for many developing countries. The majority of global coffee production comes from around 20-25 million smallholder families in developing countries. As individual certifications are too expensive smallholders have to participate in farmer organizations, e.g. cooperatives, in order to access cheaper group certification. Governments and international donors support coffee certification schemes and assume that these link farmers to high-value markets, increase producers¿ incomes, change power and information asymmetries in value chains, and contribute to poverty reduction. Yet, there is only weak empirical evidence that justifies this support. There are few quantitative studies which applied random sampling techniques, and analyzed the effects of certification schemes in regard of gross margins, profits, income shares and poverty levels of certified smallholder coffee producers. The role of cooperatives for the success of certification schemes has been neglected by research. The available studies have methodological limitations, for example they are based on qualitative methods only, include no more than one cooperative or one certification standard, or cooperatives are non-randomly sampled.This research seeks to fill the identified knowledge and methodological gaps. Through a combination of qualitative and quantitative research, the production and marketing strategies of small-scale coffee producers in northern Nicaragua are compared based on producers that are organized in conventional, organic, and Organic-Fairtrade certified cooperatives. The analysis addresses (i) the smallholders¿ household level and (ii) the organizational and institutional level with regard of the cooperatives and respective coffee value chains. The study aims at, first, identifying the socio-economic costs and benefits of participation in organic and Organic-Fairtrade certified coffee chains with respect to level of coffee and household incomes as well as household poverty. Second, it is examined which role the farmer organizations, their respective business models and upgrading strategies, play for the success or failure of certification schemes. Third, the integration of coffee farmers and their cooperatives into the coffee value chain, the structure and functioning of the value chains and the value adding effect of certification is examined.

  • av Manuela Nagel
    316,-

    Against the background of 7.4 million accessions stored in genebanks, long-term survival of stored seeds is an important trait. This study intended to elucidate genetic and biochemical mechanisms underlying barley (Hordeum vulgare L.) seed deterioration with respect to genetic diversity at different storage treatments ranging from cold storage with low seed moisture content (smc) to experimental seed ageing with high smc.On the basis of an assumed genetic impact on seed deterioration quantitative genetic analyses using four mapping populations were applied. Seeds of three bi-parental barley mapping populations were experimentally aged. Subsequent quantitative trait locus (QTL) analyses revealed 4 major loci on chromosomes 2H, 5H and 7H explaining a phenotypic variation up to 54%. Detected loci were confirmed by the fourth population that compromises a collection of independent barley accessions. These genotypes, multiplied in two field plots and experimentally aged were analysed by a genome-wide association approach which resulted in 105 marker-trait associations (MTAs) at 32 loci. Putative functions of MTAs and closely linked QTLs revealed predominantly biotic and abiotic stress affect seed longevity.

  • av Daniel Kaufmann
    360,-

    Size effects can cause a significant increase in the strength of a metal. In the past, this effect has been extensively investigated for fcc metals but until today only limited knowledge exists on the size dependent behaviour of bcc metals. Bcc metals are used in many applications and, therefore, knowledge of their size scaling is of technological importance. Size effects in bcc metals are also interesting from a fundamental scientific point of view, since underlying dislocation processes of bcc metals differ from those of fcc metals. In contrast to fcc metals, where screw and edge dislocations have similar mobilities with little or no temperature dependence, the mobility of screw dislocations in bcc metals is strongly temperature dependent. In bcc metals, screw dislocations move by thermally activated kink pair nucleation and motion. Below the material dependent athermal temperature, their mobility is lower than that of edge dislocations. In this work, the deformation of Ta and -Fe micropillars was studied using microcompression experiments. Pillars were produced using a focused ion beam microscope and were compressed in a nanoindenter using a flattened tip. The experiments show that there is a distinct size effect in bcc metals. The size effect of -Fe is similar to the one found in typical fcc metals, and it is more pronounced than the one observed in Ta. A combination of this data with data obtained from fcc metals and from several other bcc metals indicates that the size dependence of bcc metals is temperature dependent. The differences in the mechanical behaviour between fcc and bcc metals can be attributed to the difference in mobility of screw dislocations in fcc and bcc metals. Results from microcompression experiments also indicate that screw dislocations control the deformation process. The results of these experiments can be explained by surface enhanced mobilities of screw dislocations. Overall, the mechanical behaviour of small bcc metals may be described by scaling laws as known from fcc metals and an additional temperature dependent component arising from the limited mobility of screw dislocations.

  • av Anna Shumilina
    486,-

    The book describes a new mathematical model for intracellular protein folding and the implementation of this model in the form of a novel simulation software. Besides, the related biological, chemical, and physical background, important for understanding and rationalization of the proposed model, is outlined, and a short overview of the best-known methods for protein structure prediction and molecular modeling is given.The first chapter provides a general introduction to the problem, characterizes the chemical structure of proteins, and summarizes amino acid properties, including chirality and ionization behavior. After that, the principles of quantum mechanics and their consequences for the molecular structure are described. The discussion goes over to covalent and hydrogen bonding, as well as to electrostatic and van der Waals interactions. Further, some known facts about the three-dimensional structure of proteins and typical conformations of amino acids are outlined, followed by a quick glance at the hydrophobic effect and the interaction of charged groups with the solvent. Later on the focus is shifted to biological aspects, starting with chaperons and assisted protein folding, mentioning prions, which put into question the popular hypothesis about the global energy minimum of any native structure, and continuing with details of protein synthesis in the cell, which constituted the basis for the proposed model. The chapter finishes with a short description of experimental methods for protein structure prediction and with some information about databases for storage of known protein structures.The second chapter starts with a short overview of the knowledge-based protein structure prediction and ab initio protein folding approaches, then continues with empirical molecular mechanics force fields, typically used for molecular modeling. After that, it describes computation of atomic partial charges with a focus on the procedure of J. Gasteiger and M. Marsili, and proceeds with some models for hydrogen bonding. The chapter ends with a discussion about implicit solvation models.The third chapter describes the new modeling approach and some mathematical theory developed in relation to it. The idea of the model is to simulate a process resembling intracellular cotranslational folding. An attachment of a new residue is performed in a way that the formed peptide group is disposed in the trans conformation, and only the chain twisting about certain single bonds is allowed. Transitions with an energy increase are permitted to a limited extent. Beside the electrostatic and van der Waals interactions, the proposed model incorporates hydrogen and disulfide bonding, solvation effects, and dielectric screening at the protein surface. A general expression connecting interatomic distances and dihedral angles is derived, which resulted in a formulation of the model in the space of molecular torsion angles. Twisting forces are computed analytically and utilized for the improvement of computational efficiency the folding simulations. Besides, equations for dynamics in the space of torsion angles are derived, and a conclusion related to folding pathways is drawn.The last chapter discusses some non-technical details related to the implementation of the proposed model, including a number of developed algorithms, and the resulting simulation software. The chapter ends with a short discussion of simulation results and with an outlook.This book is aimed in the first place to biophysicists and bioinformaticians, but can be also interesting for theoretical chemists, mathematicians, and molecular biologists, since it includes a broad interdisciplinary overview accompanied by unique visualizations, which were performed with the help of the simulation software developed by the author.

  • av Alexander De Antoni
    526,-

    An ethnic group¿s specific social life depends on a selection of manners in which members approach one another or take position towards a person or group. The characteristics of this conventional behaviour create social identity. This book will prove how a structure pattern functions as a basic principle for the moulding of various forms of social habits.In order to communicate such a pattern it is coded into myths and passed on with mythical tales and motives. Myths therefore enable both the constancy and the transformation of ethnic identity in a social community.A mythical song of the Asmat in Papua will be quoted in order to decode a specific structural pattern. It turns out to be interwoven with a socio-political, economical and cosmological context. But also features of the landscape that this ethnic group inhabits, offer astonishing analogies to the pattern, which determines its social and cultural life. Both are characterized by the absence of clear borders.Symbolically, the Asmat¿s strategy to abolish borders is represented by a dugout canoe. It is this means of transport that makes social relationships possible. In a carved form, designed for ritual purposes, it is also considered as a vehicle for ancestors returning to their home-village to attend a festival. It eliminates separation in our world but also represents the absence of division to other spheres of existence. The dugout is therefore an illustrative symbol for the structure pattern upon which the social life of the Asmat is based.

  • av Dirk S Drechsel
    486,-

    The topic of the thesis is banks and the Swiss economy. It consists of four main partswhich make empirical contributions to the fields of banking, productivity analysis,financial economics, macroeconomics and economic history. The first part describesthe construction of a newly developed data set, containing balance sheets and profit& loss accounts of Swiss banks from 1906-2007.The second part is about banking intermediation efficiency in Switzerland. Bankingefficiency is estimated utilizing stochastic frontier analysis. The results show thatstate owned cantonal banks and co-operatives are more stable in terms of efficiencythan big universal banks. There is little variation in cost efficiency. Scale effects arepresent, while banks with market power do not seem to obstruct smaller banks. Arisk measure based on the Basel II standardized approach is included to incorporatethe cost of risk.The third part investigates Swiss banking crises and their effect on the Swiss economy.Banking crises are determined by estimating deviations from potential returnon equity with Bayesian dynamic stochastic frontier analysis. Several periods of distressare revealed. The most prominent are the Great Depression, the mortgage crisisof the 1990s, the burst of the dot-com bubble and the onset of the sub-prime crisis in2007. These are put in historical perspective. The deviations from potential outputare included in a Bayesian dynamic factor model in order to generate an aggregatedbanking distress measure. To estimate the macroeconomic effects of banking crisesthis indicator is used in a time-varying coefficients Bayesian vector autoregressionwith sign restrictions identification setup. The results show that GDP growth, thebanking sector and credit conditions responded strongly to banking shocks. Thedependence of the Swiss economy on its banking industry is strongest during theGreat Depression, weak in the mid 20th century and regains importance during the1990s/2000s. Credit conditions relax earlier now than in the 1930s, while banksrecover more quickly.The fourth part studies the reduction in macroeconomic volatility in Switzerlandfrom 1949-2006 with respect to an abatement in economic shocks. The data for aset of variables are compared with the predictions from a dynamic stochastic generalequilibrium model with financial frictions using a relative mean square approximationerror. The hypothesis, that a large part of the reduction in macroeconomicvolatility in the last 25-30 years could be the consequence of ¿good luck¿ in form ofsmaller shocks, cannot be rejected.

  • av Marcel C. Tiemann
    280,-

    This publication examines Europe¿s strong dependency on importing essential minerals and metals for their industries and if a strategic European Union Sovereign Wealth Fund (EUSWF) is a possible solution for investing directly in producing countries in order to maximize the security of supply. This would be advanced measures for the ¿Raw Materials Initiative¿ (RMI) which has been launched by the European Commission in 2008 to react to the future development of minerals and metals which faced a scarcity based on natural limitation and increasing prices. Both are driven by a global shift from western economies to eastern economies based on booming economies and their high demand to satisfy the growth. The publication states that countries with a state capitalism have direct access to these relevant minerals and metals neither through their state-owned enterprises in their own economies nor through strategic foreign direct investments (FDI) in these elements by Sovereign Wealth Funds (SWFs) or state-owned enterprises, too. The results of the survey show that these economies are going to have or already have an advantage attributable to this behaviour and that the European Union (EU) missed this opportunity decades ago. Moreover does this way of political behaviour not coincide with the idea of a capitalist economic system, which is based on a free and fair trade. Finally, the EU seems to cooperate in this issue less than they should or might be able to. Indications were found related to the Europe 2020 strategy that the EU could overcome this weakness.

  • av Lea Brinkmann
    386,-

    Outdoor group housing is increasingly recognized as an appropriate housing system for horses. However, ambient temperatures in Central Europe can range from -25°C in winter to +35°C in summer, thus exposing animals to extreme environmental conditions. Simultaneously, food quantity and quality may vary substantially with seasons. Whether domesticated horses can adapt to these harsh conditions, like their wild ancestor the Przewalski horse, has been in debate, because domestication represents a manipulation of the natural selection process. Little information is available on the behaviour of domestic horses under such conditions. Therefore, this dissertation analysed physiological and behavioural adaptation strategies of a robust domesticated horse breed, the Shetland pony, under semi-extensive housing conditions. The main focus was on changes in metabolic rate, water metabolism, locomotor activity, lying time and several blood parameters over the course of a year.Die Gruppenhaltung von Pferden unter Außenklimabedingungen wird zunehmend als tiergerechte Haltungsform angesehen. Allerdings sind die Pferde dabei starken klimatischen Schwankungen ausgesetzt, da die Umgebungstemperaturen in Zentraleuropa von -25°C im Winter bis +35 °C im Sommer reichen können. Gleichzeitig kann die Futterqualität und -quantität erheblich innerhalb des Jahres schwanken. Da die Domestikation eine Manipulation der natürlichen Selektion darstellt, ist es fraglich, ob sich domestizierte Pferde, wie ihre wilden Verwandten, die Przewalski Pferde, an solch raue Umweltbedingungen anpassen können. Bisher gibt es wenige Informationen über das Verhalten domestizierter Pferde unter solchen Haltungsbedingungen. Ziel dieser Dissertation war folglich die Analyse von Verhaltensänderungen und physiologischer Adaptationen einer domestizierten, robusten Pferderasse, dem Shetland Pony, unter semi-extensiven Haltungsbedingungen. Das Hauptaugenmerk liegt dabei auf Änderungen der Stoffwechselaktivität, des Wasserumsatzes, der Bewegungsaktivität und der Liegedauer sowie unterschiedlicher Blutparameter im Jahresverlauf.

  • av Dirk Wall
    470,-

    Die vorliegende Arbeit beschäftigt sich mit Oberflächendiffusion und Strukturbildung an Oberflächen, speziell im Fall Silber auf Silizium. Unterschiedliche Methoden werden kombiniert um Si(001) und Si(111) Oberflächen als auch dazwischen liegende Orientierungen zu untersuchen. niedrigenergetische Elektronenmikroskopie (LEEM) und photoemissions Elektronenmikroskopie (PEEM) wurden verwendet um die Wachstumsdynamik und den Einfluss von Oberflächendiffusion auf die Strukturbildung an Oberflächen unter Ultrahochvakuum (UHV) Bedingungen zu untersuchen. Es wurden ein- und multi-kristalline Ag Inseln und selbstorganisierte Ag Drähte auf unterschiedlichen Si Oberflächen untersucht. Hierfür wurde Ag bei hohen Temperaturen auf Oberflächen aufgebracht, wobei die meisten Untersuchungen in-situ erfolgten. Die Struktur der Ag Inseln und Drähte und deren Orientierung zum Substrat wurde hauptsächlich mit niederenergetischer Elektronenbeugung an kleinen Bereichen (µ-LEED), hochauflösender niederenergetischer Elektronenbeugung (SPA-LEED) und Rasterelektronenmikroskopie (SEM) untersucht. Für die SEM Untersuchungen wurden die präparierten Proben aus dem UHV entnommen um sie in ein SEM zu transferieren und eine statistisch bessere Aussagekraft zu erreichen.Ag(001) und Ag(111) Inseln wurden bei Temperaturen von bis zu 700°C gewachsen. Mit steigender Wachstumstemperatur verändert sich die überwiegende Form der Inseln von hexagonal zu dreieckig. Die relative Drehung zum Substrat wurde Untersucht und mit einem modifizierten gitter-koinzidenz Modell (CSL) verglichen. Der Vergleich zeigt eine ausgesprochen gute Übereinstimmung der experimentellen Daten mit der Theorie, bei der praktisch alle Drehwinkel erklärt werden.

  • av Max Christian Funck
    350,-

    Producing high quality optical systems at reasonable cost is a challenge andsolutions enabling cost-efficient production in small to medium quantities needto be developed in order for Germany to stay competitive on the global market.Both, performance and cost are largely influenced by manufacturing andassembly tolerances and frequently compensation such as alignment is requiredto achieve the demanded performance.This dissertation systematically develops combinatorial assembly as acompensation strategy which does not require iterations and as such is suitablefor automated production of small series. A pool of components andsubassemblies, necessary for the assembly of a series of systems, ischaracterized prior to the assembly and measurement results are stored in adatabase. Then, optimal component combinations are found during a modelbasedselection process.The application of combinatorial assembly to optical systems requires a delicatechoice of parameters for characterization, modules and tolerances beforecomponents are manufactured. Predicting the as-built performance ofcombinatorially assembled systems with high accuracy is therefore necessaryand a dedicated tolerance analysis concept based on Monte Carlo analyses isproposed. The concept is universally applicable to problems that can bemodelled with ray-tracing and is implemented using a combination of raytracingsoftware, logic calculator and database. This makes it possible toaccurately analyze the impact of tolerances, production volume and additionaluncertainties on the performance of combinatorially assembled optical systems.For optimal compensation, tolerance distributions should match each other in aspecific way and it is illustrated that this can be difficult to realize for some lensdesigns due to manufacturing limits. In order to reduce this restriction, designstrategies increasing combinatorial compensation are derived. Adapting theoptical design from the outset to suit combinatorial assembly can shifttolerance sensitivities from one component to another. Compensation can beenhanced and the influence of uncharacterized parameters reduced. In usingcombinatorial assembly in conjunction with desensitization, systems with highernominal performance yet reduced tolerance demands can be build. This is anentirely new approach and a first step towards a more integrated developmentof optical systems.

  • av Ludwig Häberle
    450,-

    The study ¿Business Aviation Study Switzerland 2022¿ examines the impact, benefits and trends of Business Aviation with a specific emphasis on the Swiss market. Outlining the economic impact by focusing on the national and regional Swiss Business Aviation airports and their related stakeholder benefits, the study highlights Business Aviation as an integral part and backbone of the highly efficient Swiss aviation system. In 2021, Switzerland recorded close to 100,000 Business Aviation aircraft movements ¿ exceeding the level of 2019. In light of the COVID-19 related crisis of scheduled airline traffic, Business Aviation has proven resilient temporarily increasing its share in total aircraft movements to 27 %. Thus, Business Aviation remains a reliable and irreplaceable partner securing Switzerland¿s connectivity, particularly in times of crisis. Looking to the future, Business Aviation opens up the opportunity to act as an innovation driver and technological pioneer paving the way for sustainable aviation in the long term.

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