Ein viel diskutiertes Thema unserer Zeit ist die Zukunft der Energiegewinnung und Speicherung. Dabei nimmt die Nanowissenschaft eine bedeutende Rolle ein; sie führt zu einer Effizienzsteigerung bei der Speicherung und Gewinnung durch bereits bekannte Materialien und durch neue Materialien. In diesem Zusammenhang ist die Chemie Wegbereiter für Nanomaterialien. Allerdings führen bisher die meisten bekannten Synthesen von Nanopartikeln zu undefinierten Partikeln. Eine einfache, kostengünstige und sichere Synthese würde die Möglichkeit einer breiten Anwendung und Skalierbarkeit bieten. In dieser Arbeit soll daher die Darstellung der einfachen Synthese von Mangannitrid-, Aluminiumnitrid-, Lithiummangansilicat-, Zirkonium-oxinitrid- und Mangancarbonatnanopartikel betrachtet werden. Dabei werden die sogenannte Harnstoff-Glas-Route als eine Festphasensynthese und die Solvothermalsynthese als typische Flüssigphasensynthese eingesetzt. Beide Synthesewege führen zu definierten Partikelgrößen und interessanten Morphologien und ermöglichen eine Einflussnahme auf die Produkte. Im Falle der Synthese der Mangannitridnanopartikel mithilfe der Harnstoff-Glas-Route führt diese zu Nanopartikeln mit Kern-Hülle-Struktur, deren Einsatz als Konversionsmaterial erstmalig vorgestellt wird. Mit dem Ziel einer leichteren Anwendung von Nanopartikeln wird eine einfache Beschichtung von Oberflächen mit Nanopartikeln mithilfe der Rotationsbeschichtung beschrieben. Es entstand ein Gemisch aus MnN0,43/MnO-Nanopartikeln, eingebettet in einem Kohlenstofffilm, dessen Untersuchung als Konversionsmaterial hohe spezifische Kapazitäten (811 mAh/g) zeigt, die die von dem konventionellen Anodenmaterial Graphit (372 mAh/g) übersteigt. Neben der Synthese des Anodenmaterials wurde ebenfalls die des Kathodenmaterials Li2MnSiO4-Nanopartikeln mithilfe der Harnstoff-Glas-Route vorgestellt. Mithilfe der Synthese von Zirkoniumoxinitridnanopartikeln Zr2ON2 kann eine einfache Einflussnahme auf das gewünschte Produkt durch die Variation derReaktionsbedingungen, wie Harnstoffmenge oder Reaktionstemperatur, bei der Harnstoff-Glas-Route demonstriert werden. Der Zusatz von kleinsten Mengen an Ammoniumchlorid vermeidet, dass sich Kohlenstoff im Endprodukt bildet und führt so zu gelben Zr2ON2-Nanopartikeln mit einer Größe d = 8 nm, die Halbleitereigen-schaften besitzen. Die Synthese von Aluminiumnitridnanopartikeln führt zu kristallinen Nanopartikeln, die in eine amorphe Matrix eingebettet sind. Die Solvothermalsynthese von Mangancarbonatnanopartikel lässt neue Morphologien in Form von Nanostäbchen entstehen, die zu schuppenartigen sphärischen Überstrukturen agglomeriert sind. / The development of new methods toward alternative clean energy production and efficient energy storage is a hot topic nowadays. In this context nanoscience has an important role to find suitable ways of increasing the efficiency of storage and production of energy of already known materials and new materials. However, until now the most well-known syntheses of MnN0,43 and Zr2ON2 nanoparticles lead to undefined particles. A simple, cheap and safe synthesis would offer the possibility of broader applications and scalability. We herein present the so-called urea-glass route which is used as a sol-gel process. This synthetic route leads to well-defined particle sizes, novel particle morphologies and allows the tailoring of the desired products. In the case of the synthesis of manganese nitride nanoparticles (MnN0,43), nanoparticles with a core-shell structure are obtained, their use as conversion materials in batteries is first introduced. On the other hand, the formation of zirconium oxynitride nanoparticles (Zr2ON2) can be easily influenced by varying the reaction conditions such as the amount of urea or the reaction temperature. The addition of small amounts of salt prevents the formation of carbon in the final product, leading to yellow Zr2ON2 nanoparticles with a size of d = 8 nm which show semiconductor behavior.

The use of GPS observations for investigating routing behaviors can be a good alternative to using more traditional traffic simulation models. In this paper, a method for inferring paths from GPS observations is proposed. Further, a route set generation algorithm is implemented. The inferred trips are used for the calibration of the parameters in the route set generation algorithm. The investigated network is part of the Interstate 210 freeway east of Los Angeles, USA. The results shows significant differences in number of eastbound travelers choosing to travel north of, south of, and on the freeway during regular days compared with the incident day. The travel times are also higher during the incident day. Different travel times as costs on the links have a large impact on the results from the route set generation algorithm. The conclusion is that the implemented methods can be used to gain a better understanding about routing behavior. However, to use the results for decision making, more input data with better precision should be used.

In a lot of big cities, the traffic network is overloaded, with congestion and unnecessary emissions as consequence. Therefore, different traffic control methods are useful, especially in case of an incident. One key problem for traffic control is traffic prediction and the aim of this thesis is to develop, calibrate and evaluate a route flow model using only observed travel times and travel demand as input. The route flow model was used to calculate the metric link flow destination distribution, that presents to which destinations the travelers on a link are going in percentage.

Les méthodes de design et de construction des routes développés dans le sud canadien ont maintenant besoin d’être adaptés aux environnements nordiques du pays afin de prévenir le dégel dramatique du pergélisol lors de la construction d’une nouvelle route. De plus, le réchauffement climatique occasionne présentement d’importants problèmes de stabilité des sols dans le nord canadien. Ces facteurs causent des pertes importantes au niveau des capacités fonctionnelles et structurales de l’Alaska Highway au Yukon sur un segment de plus de 200 km situé entre le village de Destruction Bay et la frontière de l’Alaska. Afin de trouver des solutions rentables à long terme, le ministère du transport du Yukon (en collaboration avec le Federal Highway Administration du gouvernement américain, Transports Canada, l’Université Laval, l’Université de Montréal et l’Alaska University transportation Center) a mis en place 12 sections d’essais de 50 mètres de longueur sur l’autoroute de l’Alaska près de Beaver Creek en 2008. Ces différentes sections d’essais ont été conçues pour évaluer une ou plusieurs méthodes combinées de stabilisation thermique telles que le drain thermique, le remblai à convection d’air, le pare-neige / pare-soleil, le remblai couvert de matières organiques, les drains longitudinaux, le déblaiement de la neige sur les pentes et la surface réfléchissante. Les objectifs spécifiques de la recherche sont 1) d’établir les régimes thermiques et les flux de chaleur dans chacune des sections pour les 3 premières années de fonctionnement ; 2) de documenter les facteurs pouvant favoriser ou nuire à l’efficacité des systèmes de protection et ; 3) de déterminer le rapport coûts/bénéfices à long terme pour chacune des techniques utilisées. Pour ce faire, une nouvelle méthode d’analyse, basée sur la mesure de flux d’extraction de chaleur Hx et d’induction Hi à l’interface entre le remblai et le sol naturel, a été utilisée dans cette étude. Certaines techniques de protection du pergélisol démontrent un bon potentiel durant leurs 3 premières années de fonctionnement. C’est le cas pour le remblai à convection d’air non-couvert, le remblai à convection d’air pleine largeur, les drains longitudinaux, le pare-soleil / pare-neige et la surface réfléchissante. Malheureusement, des problèmes dans l'installation des drains thermiques ont empêché une évaluation complète de leur efficacité. / Road design and construction techniques developed in southern Canada definitely need to be adapted to northern environment to prevent dramatic permafrost thawing after new road construction. Furthermore, climate warming causes now important soil stability problems in the Canadian far north. All these factors lead to a loss of the functional and structural capacities of the Alaska Highway over a 200-km section mainly from Destruction Bay to the Alaska border. To find long term and cost-effective solutions, Yukon Highways and Public Works (in collaboration with the Alaska University Transportation Center, Transport Canada, le U.S. Federal Highways Administration, l’Université de Montréal and l’Université Laval) constructed 12 instrumented sections on the Alaska Highway near Beaver Creek (Yukon) in 2008. These sections experiment one or several combined methods of thermal stabilization such as convection air embankment, heat drains, snow/sun shed, grass-covered embankment, longitudinal culverts, reflecting surfaces and snow clearing on embankment slopes. The main objectives of this project are 1) to analyze the ground thermal regime and the heat fluxes for each of the 12 sections during their first three years in service; 2) to document all factors which can facilitate or disrupt the efficiency of the protection systems and; 3) to determine the long term costs / benefits ratio for every technique tested. In order to do this, a new method based on the calculation of heat extraction Hx and heat induction Hi index at the interface between the embankment and the natural ground has been used in this study. The permafrost mitigation techniques that showed good potential for cooling by reducing active layer thicknesses were the ACE uncovered, the longitudinal culverts, the snow/sun shed and the light-coloured aggregate BST (although this was only effective along the central part of the highway). Unfortunately, problems in the installation of the heat drain techniques prevented a full assessment of their effectiveness. The durability of the sections as well as their long-term cooling potential must also be assessed to complete the economic analysis provided in this study.

Thesis (MA (Geography and Environmental Studies))--University of Stellenbosch, 2006. / The Garden Route is located along the southern Cape coast of South Africa, between the Outeniqua Mountain Range and the coast, stretching from Gourits River in the west to Bloukranz River in the east. This region is recognised as a holiday destination and the centre of the southern Cape’s tourism industry. It has also gained popularity as a golfing destination set to proliferate in terms of new golfcourse developments (Golf Digest 2004; Gould 2004; Granger 2003). No known complete academic or public record is however available for the study area in which all the golf development types, namely short courses, public-municipal golf-courses and residential golf estates, are recorded. This leaves a gap in the understanding of the Garden Route as a golfing destination, as well as opening the floor for public speculation about the status of the Garden Route golfscape. This situation emphasises the need for a description of the Garden Route golfscape in order to achieve a better understanding of it and of the Garden Route as an emerging golfing destination. The research aspires to describe the Garden Route golfscape in terms of the geographic spatial distribution and characteristics of all the golf development types mentioned. It also aims to analyse how the public and developers of golf developments perceive the Garden Route golfscape. The research has shown that amongst the four identified intra-regional golfscapes of the Garden Route, namely the Mossel Bay, George, Knysna and Plettenberg Bay intra-regional golfscapes, the George intra-regional golfscape has been affected the most by golf developments. This intra-regional golfscape has the greatest number of existing golf developments, as well as the highest number of new golf development applications followed by Mossel Bay, Knysna and Plettenberg Bay. It is also clear from the research that the press, through publishing factually incorrect and biased information, plays a significant role in negatively affecting the public’s perception about the Garden Route golfscape. The literature, as well as the results of the public opinion poll, identifies residential private golf estate developments as the development type responsible for controversial golf debates. The survey indicated that there is less concern and objection to public-municipal golf-courses and short courses. The lack of public support for golf developments is as a result of the fact that the public is not convinced that either the natural environment or tourism, will benefit from the Garden Route developing into an international golfing destination. At the time of research, the Garden Route hosted 22 approved golf developments of which nine are short courses, another nine are golf estates and the remaining four are public municipal courses. A total of eight new golf estates are proposed for the Garden Route. There are no proposals for new public-municipal golf-courses or short courses. The research has highlighted that existing challenges associated with Garden Route golf developments must be quantified through future research in order to compare the impacts (economic, social and environmental impacts) with that of other land uses in the study area. Results from such future exercises, combined with future in-depth environmental and human resource audits of the area, will help determine the carrying capacity of the study area for golf developments, which will in turn contribute to an even better understanding of the Garden Route golfscape.

Die Mobilität von Personen und Gütern, insbesondere in Städten, ist der Motor einer Volkswirtschaft. Dieser Motor kommt jedoch ins Stottern, wenn Staubildung im Stadtstraßennetzwerk einsetzt. Eine unvermeidbare Ursache von Staubildung stellen Verkehrsstörfälle dar, die schlimmstenfalls zu Gridlocks führen können. In der Folge werden hohe Kosten für Verkehr, Wirtschaft und Umwelt verursacht. Mit welchen Gegenmaßnahmen kann die Staubildung im Netzwerk effektiv bewältigt werden? Wie können entsprechende Gegenmaßnahmen realistisch noch vor einem praktischen Einsatz bewertet werden? Ausgehend von diesen Fragestellungen, widmet sich diese Dissertation der Entwicklung eines ereignisorientierten Routenwahlmodells für den Stadtstraßenverkehr und eines selbstorganisierten Störfallmanagements als Gegenmaßnahme zur Reduzierung negativer Auswirkungen der Staubildung. Zur Modellierung des Routenwahlverhaltens in ereignisreichen Stadtstraßennetzen wird das ereignisorientierte Routenwahlmodell entwickelt. Der Ausgangspunkt des Modells ist die diskrete Wahltheorie. Entscheidungsprozesse einzelner Autofahrer werden vor und während der Fahrt direkt simuliert. Der Entscheidungsprozess ist dabei maßgeblich von Beobachtungen lokaler Verkehrsbedingungen geprägt. Somit wird nachgebildet, dass Autofahrer flexibel auf unvorhergesehene Ereignisse durch Routenwechsel reagieren können. Auf diese Weise ist eine realistische Simulation des Routenwahlverhaltens von Autofahrern in der Stadt möglich. Das ereignisorientierte Routenwahlmodell ist zudem generisch formuliert. Es lässt sich zur Bewertung von Gegenmaßnahmen für störfallbedingte Staubildung einsetzen und bedient darüber hinaus ein breites Anwendungsspektrum. Der zweite Beitrag dieser Dissertation ist ein selbstorganisiertes Konzept für ein Störfallmanagement in Stadtstraßennetzen als Gegenmaßnahme zur Staubildung. Es vereint zwei lokal wirkende Prinzipien, deren Ausgangspunkte die Lichtsignalanlagen im Stadtnetzwerk sind. Mit verlängerten Rotzeiten werden Fahrzeuge an einer Kreuzung an der Einfahrt in einen Straßenabschnitt gehindert, wenn ein vorgesehener Rückstaubereich ausgeschöpft ist, da andernfalls Blockaden auf den Kreuzungen entstehen. Gleichzeitig werden noch freie Richtungen an der Kreuzung durch verlängerte Grünzeiten attraktiver gestaltet, um Autofahrer zum Umfahren der Staubildung zu motivieren. Die Anwendung der lokalen Wirkungsprinzipien stellt sich vollständig selbstorganisiert, d.h. ohne Vorgabe eines Planers, mit dem Ausmaß der Staubildung im Netzwerk ein. Simulationsstudien in zwei unterschiedlich komplexen Netzwerken haben die Machbarkeit des selbstorganisierten Störfallmanagements nachgewiesen. Gegenüber einem gewöhnlichen Netzwerk konnte für alle untersuchten Störfälle die Akkumulation zusätzlicher Fahrzeuge im Netzwerk während des Störfalls signifikant reduziert werden. / The mobility of people and goods, especially in urban areas, is of significant importance for national economies. However, recurrent congestion in urban road networks, caused by increased traffic demand, considerably restrains mobility on a daily basis. Another significant source of congestion are traffic incidents which even might lead to gridlock situations. Congestion raises high costs for traffic, economy and environment. Which countermeasures should be applied for an effective management of urban congestion? How can appropriate countermeasures be realistically evaluated? Based on these questions, this thesis is devoted to the development of an event-oriented route choice model for urban road traffic and a self-organized incident management strategy as an effective countermeasure for urban congestion. The first contribution of this thesis is an event-oriented route choice model for urban road networks. It is based on discrete choice theory and models decision-making processes of individual motorists before and during their journey. A key aspect of the proposed model is the motorist's ability to observe local traffic conditions. These observations are then included in the decision process. In this way, it can be modeled that motorists respond to unforeseen events by route revisions. This allows a realistic simulation of the route choice behavior of motorists in naturally eventful urban road networks. Furthermore, the event-oriented route choice model is flexibly formulated. It can be used for the evaluation of countermeasures for incident-related congestion and, moreover, allows a wide range of applications. The second contribution of this thesis is a self-organized concept of an incident management strategy in urban road networks as a countermeasure for urban congestion. It combines two locally acting principles on the basis of traffic lights in an urban road network. The inflow of vehicles into a road segment is regulated with restricted or skipped green times as soon as an allocated queuing capacity is depleted. Otherwise, blockages would result on the intersection. At the same time, yet free alternative directions are served with regular or even extended green times and, thus, might become more attractive to the driver than the original congested direction. The application of these local principles is realized in a completely self-organized manner, thereby scaling directly with the extent of congestion in the urban road network. Simulation studies in two networks with different complexity have proven the feasibility of the self-organized incident management. Compared to an ordinary network, the extents of additional vehicles due to investigated incidents were significantly reduced.

In South Africa, there is a growing concern regarding the sustainability of bark harvesting due to the reduced availability of medicinal trees in natural areas and the slow growing and slow-reproducing nature of South Africa’s indigenous trees, of which some have specific habitat requirements and a limited distribution. With an estimated 80% of all Africans in South Africa still relying on plant material for their basic healthcare needs, approximately 200 000 traditional healers and an estimated 63 000 commercial harvesters, medicinal plants are being exploited to extinction. The aim of the study was to determine whether bridge-grafting could be used to restore growth in girdled Ocotea bullata and Curtisia dentata trees as these two medicinal tree species are listed on the South African Red List as ‘endangered’ and ‘near threatened’ due to overexploitation. These trees were also historically used in furniture production and general carpentry, which increased these trees’ vulnerability to extinction. Bridge-grafting is a technique widely described in horticultural literature but has not been used to restore growth in medicinal tree species with extensive harvesting damage. Metabolomics as analytical method is a relatively new science, but it is very useful, accurate and repeatable in obtaining knowledge on the metabolites present in a plant, and for determining the concentrations of metabolites. NMR metabolomics is, however, not sensitive enough to quantify metabolites with very low concentrations such as plant hormones. The results achieved showed that O. bullata and C. dentata responded differently to girdling and bridge-grafting regarding location of callus initiation, callus development, rate of callus development, basal shoot initiation and development and their sucrose source-sink relationships. NMR metabolomics showed that seasonality was an important factor affecting metabolite responses in both species. NMR metabolomics also showed that after one year, there were no differences in responses above and below the girdle wounds, nor were there differences between the grafted trees and the normal control trees. iv Although the method of bridge-grafting was successful in restoring the growth of O. bullata and C. dentata with this study, much more research needs to be conducted to prevent endangered girdled medicinal trees from becoming extinct, to maintain tree species diversity, genetic diversity and biodiversity. / School of Environmental Sciences / M. Sc. (Nature Conservation)

Flight planning is a large part of the air traffic operations that are presently being conducted. Airlines strive to achieve the cheapest and most cost effective routes for their flights, resulting in aircraft sometimes flying longer routes in order to avoid expensive airspaces with high unit rates. This issue has been an ongoing obstacle for the Swedish air navigation provider, LFV, as some airlines tend to fly over the Baltic Sea, through the Baltic countries, instead of the shorter route through Swedish airspace. These protracted routes result in extra kilometers being flown yearly,consuming extra fuel, as well as imply a revenue loss to LFV and Sweden. The conclusions of this study is that the airspace dodging behavior generate a revenue loss to LFV, totaling approximately €5 032 354 million per year. Should these flights fly the shortest route between their origin and destination, the before mentioned sum would mean an increase in LFV’s reported revenue from air traffic control services by 2%. Airspace dodging also results in roughly 380 408 superfluous kilometers being flown and 1 874 486 liters of additional fuel being consumed every year.

Modern vehicles have an increasing number of advanced features requiring network coverage in order to function properly. In order to facilitate the requirements of such features and allow more advanced applications, we consider the possibility of planning routes that take signal strength into consideration. Previous work have shown the relationship between TCP throughput/goodput and signal strength. In this thesis signal-aware route planning is presented, implemented, and validated. Crowd-sourced map and signal data (3G) from two sources is used for building a signal coverage map. The signal and map data is validated in a field experiment, where routes were travelled while measuring the signal strength. The field experiment showed gains in signal characteristics when deviating from the shortest possible path. The average signal strength increased by 11 dBm between algorithms and the shortest possible path. Lastly, routes were planned for all possible sources and destinations in a given urban area. The results of this calculation confirms the patterns found in the field experiment.

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