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Ökologisch-orientierte Tourenplanung bei Verwendung heterogener Flotten
Get PDFVehicle routing with ecological objectives is much more challenging than vehicle routing with classical objectives such as distance minimization. First, a reasonable forecast of the amount of consumed energy respectively produced emissions is required to get input data for the optimization of ecological friendly routes. Furthermore, electric vehicles and combustion-powered vehicles differ substantially with respect to several characteristic factors that have major impacts on vehicle routing. This PhD-theses presents an analyses and a comparison of several emission calculation models as well as several studies on vehicle routing with ecological objectives and heterogeneous fleets. First, the effect of split deliveries is shown. Second, electric vehicles are opposed to combustion-powered vehicles. Third, the impact of introducing recharge stations for electric vehicles is analyzed. Finally, the characteristics of idealized mixed fleets are analyzed as well as the identification of small heterogeneous fleets that consume only small amounts of additional energy compared to an idealized fleet consisting of an arbitrarily large number of vehicles
Definition und Quantifizierung der Drapierbarkeit von multiaxialen Gelegen durch die Vermessung von Einzeleffekten
No full textThis dissertation presents a definition of drapeability that is meant to broaden its scope to include not only the important effects of shearing and wrinkling, but all constituent effects such as gap formation, undulations, loops (tow buckling) and fabric anisotropy. This definition is complemented by an experimental test device to measure and quantify all of these effects in a single, standardized setup (available as the Textechno Drapetest). The Drapetest utilizes optic measurement technology that is coupled with digital image anlysis software to detect and measure fibre positions and orientation, and fabric topology. For each of the defined drapeability effects characteristic values were generated from this optical data that can describe the intensity, distribution and extent of the effect in question. The device and methodology was empirically validated using a set of 72 specially manufactured glass fibre NCF. The interdependencies between textile design, process parameters, and drapeability effects and a semi-analytical equation for them are shown. A method to use these semi-analytical equations in the composite design process is introduced
Report and preliminary results of R/V POSEIDON cruise POS508, Las Palmas (Canary Islands) - Las Palmas (Canary Islands), 22.01.2017 - 06.02.2017.
Get PDFEntwicklung von Simulations- und Analysemethoden zur Modellierung von Störkräften im Rahmen der Satellitenmission MICROSCOPE
Get PDFIn fundamental physics, a condition for the validity of the general theory of relativity is constantly being put to test: the weak equivalence principle. The satellite mission MICROSCOPE (MICRO-Satellite a trainee Compense pour la Observation du Principe da Equivalence) shall set a new milestone, aiming at a measurement result with an accuracy of 1e-15 and thus improving previous results by two orders of magnitude. The experiment is carried out with a differential accelerometer in which two test masses of different material are held on the same trajectory by means of electrostatic forces. Therefor the mass centres of these test masses, which are concentric hollow cylinders, must coincide. Any difference in the required forces would indicate a violation of the weak equivalence principle. The desired measurement accuracy places high demands both on the measuring instrument and on the satellite, which must ensure undisturbed environmental conditions for the experiment. In order to avoid material deformation, high temperature stability is required. In addition, the satellite should protect the experiment from external disturbing forces resulting from its interaction with environmental conditions in space. For this purpose, a special attitude control system is used, which compensates for these non-gravitational forces and thus ensures a purely gravitational trajectory. The MICROSCOPE data analysis is a very complex process, as a large number of possible error sources must be taken into account including the non- gravitational forces which act on the satellite. Their influence on the measurement result cannot be completely excluded. The modelling of these disturbing forces is a central topic of this work. For this purpose, a calculation method has been implemented that can take into account complex satellite geometries by decomposing the surface using finite elements. This method enables the assignment of different material properties and the affected area can be very well determined. The calculation of the disturbance forces requires the time-dependent calculation of the satellitea s orbit and attitude. For this purpose, a simulation tool is used, which was in part developed in the framework of this work. Furthermore an analysis tool that is used to process and analyse MICROSCOPE measurement data was designed. It is used in conjunction with the disturbance force simulation and analysis to support the evaluation process of the MICROSCOPE data. In addition, the analysis tool is used to validate simulation results
The role of ego-centred networks in entrepreneurship
Get PDFThe thesis analyses the role of ego-centred networks in different entrepreneurial contexts. Based on the embeddedness approach, it merges different strands of research from social-cognitive theory, network research and institutional economics. As a result of recombining these approaches, hypotheses are derived and tested. The following three main thematic fields are addressed empirically: a) the interplay between institutional backgrounds and networks, b) effects of ego-centred social networks on social-cognitive variables such as entrepreneurial self-efficacy as well as c) gender aspects related to entrepreneurship and social networks. In order to examine these topics, both secondary data analyses and an own online survey were conducted
Age stratigraphy and basal properties of the East Antarctic Ice Sheet from radio-echo sounding measurements : and inferences about ice dynamics
Get PDFThe ice sheet internal structure is an imprint of its history and dynamics, and, additionally, the ice and enclosed air provide valuable information about the past climate. An established continent-wide stratigraphy can constrain both paleo-climate reconstructions and ice-flow models. In this study, the internal stratigraphy and basal properties of the East Antarctic Ice Sheet (EAIS) are inferred from radio-echo sounding (RES) measurements and interpreted with respect to ice dynamics. The first part evaluates the compatibility of multiple RES data sets and investigates the physical cause for RES internal reflections, ensuring their isochronicity. These reflections are used to map the age-depth stratigraphy of the EAIS. The depth distribution of paleo surfaces provides first estimates about accumulation-rate distribution and maximum age of the ice. The third part analyzes the roughness of the EAIS' base. Relationships between basal roughness, ice-flow speed and basal temperatures are observed, which could serve as a method to infer the basal thermal condition or validate modeled temperate-bed locations
Synthesis of a chlorin with annelated lactam ring as subunit for artificial photosynthetic reaction centres
Get PDFA chlorin with an annelated cyclic ketone moiety was synthesized from a tricyclic nickel complex and appropriate pyrrole building blocks. Ketone functionality of the target chlorin allows Beckmann rearrangement to yield chlorin lactams. Lactam moieties on the chlorin represent masked amino acid structures which should allow formation of peptide-like backbones, along which chlorin pigments are arranged. Due to the natural chlorin chromophores and the peptide backbone the devices should represent artificial mimetics of natural photosynthesis systems
Effective influences in neuronal networks : attentional modulation of effective influences underlying flexible processing and how to measure them
Get PDFSelective routing of information between brain areas is a key prerequisite for flexible adaptive behaviour. It allows to focus on relevant information and to ignore potentially distracting influences. Selective attention is a psychological process which controls this preferential processing of relevant information. The neuronal network structures and dynamics, and the attentional mechanisms by which this routing is enabled are not fully clarified. Based on previous experimental findings and theories, a network model is proposed which reproduces a range of results from the attention literature. It depends on shifting of phase relations between oscillating neuronal populations to modulate the effective influence of synapses. This network model might serve as a generic routing motif throughout the brain. The attentional modifications of activity in this network are investigated experimentally and found to employ two distinct channels to influence processing: facilitation of relevant information and independent suppression of distracting information. These findings are in agreement with the model and previously unreported on the level of neuronal populations. Furthermore, effective influence in dynamical systems is investigated more closely. Due to a lack of a theoretical underpinning for measurements of influence in non-linear dynamical systems such as neuronal networks, often unsuited measures are used for experimental data that can lead to erroneous conclusions. Based on a central theorem in dynamical systems, a novel theory of effective influence is developed. Measures derived from this theory are demonstrated to capture the time dependent effective influence and the asymmetry of influences in model systems and experimental data. This new theory holds the potential to uncover previously concealed interactions in generic non-linear systems studied in a range of disciplines, such as neuroscience, ecology, economy and climatology
Herstellung und Charakterisierung von Siliziumnanostrukturen für Lithium-Ionen-Batterien
Get PDFFor the use as anodes in lithium-ion batteries, silicon nanostructures were synthesized with three different methods and characterized. a-Si thin films were deposited on substrates of varying roughness with PECVD. Oxide-free porous and non-porous SiNW were synthesized with metal-assisted chemical etching and functionalized with acrylic acid. SiNW with different diameters were grown via CVD. The degradation mechanisms were investigated on the basis of the electrochemical characterization. a-Si thin films delaminated depending on roughness and film thickness that led to the temporary emergence of Li15Si4 and a reduced coulombic efficiency. Porous SiNW exhibited a reduced volume expansion and therefore a higher coulomb efficiency and reduced occurrence of Li15Si4. The grown SiNW showed little differences in their electrochemical behaviour. This is due to the drastic change in morphology from individual SiNW to a porous laye
Industrielles Wirtschaftswachstum durch gezielte Wirtschaftsförderung : das Beispiel Saudi-Arabien
No full textAnalysis of quantitative and qualitative economic growth factors as input for the industrial diversification of Saudi Arabia. Based on the findings - barriers - a specific incentive-framework was developed, tested and presented to the Saudi Arabian Government. Although the incentive framework was attractive to foreign investors several Saudi Arabian Ministries were discordant whether the incentives should be granted. Saudi Arabia missed to capitalize on the window of opportunities in the aftermath of the financial crisis 2008ff. Status of industrial diversification remain unchanged