Urban (un)planning and social vulnerability in the context of rapid urbanization and data constraints: a quantitative study of Dar es Salaam, Tanzania.

This dissertation explores intersections between vulnerability and urban planning in Sub-Saharan Africa, where distinct forms of urbanization are occurring and where there are significant data constraints limiting local studies and urban assessments in the region. The three studies which make up this dissertation offer methodological and theoretical pathways toward examining and measuring the influence of urbanization and planning factors on vulnerability of urban populations in the region. The first study is a literature review and examines existing literature for vulnerability conceptualization in urban environments, the notion of ‘urban vulnerability’, and roles of urban planning and related factors in relation to vulnerability specifically in the sub-Saharan context. The second study explores approaches to quantitatively constructing more recent urban land use data in the absence of available land use datasets in the Sub-Saharan context, particularly data with informal and formal urban land use distinctions. The third study offers a methodology and estimation models to measure and quantify planning and urbanization variables (i.e. sprawl) in vulnerability assessment. Dar es Salaam, Tanzania serves as the study area because of its rapid urbanization processes, substantial informal development and sprawling, as well as availability of reliable datasets for recent years (2014/2015) for the vulnerability assessment. Findings of the literature review include challenges in conceptualizing vulnerability in an urban environment beyond a climate focus, gaps in urban vulnerability conceptualization, underrepresentation of planning factors and measurement in vulnerability assessment, and limitations in local and urban data availability and studies in Sub-Saharan cities. Results for the second study include the construction of a 2014 urban land use dataset based on estimates from binomial logistic regression models. Results for the third study indicate formally planned urban areas are associated with higher level of quality of life and mobility. Further results indicate no impact of sprawl on social vulnerability factors of residents in the urban areas of Dar es Salaam, however, informal (i.e. unplanned) sprawl impacts residents negatively. These results provide initial steps toward investigating the influence of broader planning and spatial aspects in quantitative urban social vulnerability assessments in the Sub-Saharan context as well as similar contexts in the global south

The socioeconomic and environmental impacts of the climate policies in China

This thesis is intended to analyse the policy effects of the simulated Chinese climate policies. Without considering any benefits and influential factors, the carbon tax could effectively reduce the carbon emissions at the price of the welfare loss. Considering its ancillary (health) benefit, the tax will induce less emission reduction and welfare loss. The primary (climate) benefit of the tax will increase the carbon emissions, decrease the carbon intensity, and induce an economic boom. The induced technological change (ITC) of the carbon tax will have negative impacts on the carbon emissions, and it will increase the real GDP (RGDP) but decrease the household welfare. The inequality impacts of the carbon tax depend on the distribution of the climate damages and the payments of the abatement costs. Recycling the tax revenues will also affect the inequality impacts of the tax. Under the impacts of the projected urbanisation, the carbon tax will induce more emission reduction, less RGDP loss, and more household welfare loss. With the same amount of the targeted emission reduction as the carbon tax, the emission trading scheme (ETS) policy will induce the higher household welfare compared to the carbon tax.Open Acces

TOWARDS FINE SCALE CHARACTERIZATION OF GLOBAL URBAN EXTENT, CHANGE AND STRUCTURE

Urbanization is a global phenomenon with far-reaching environmental impacts. Monitoring, understanding, and modeling its trends and impacts require accurate, spatially detailed and updatable information on urban extent, change, and structure. In this dissertation, new methods have been developed to map urban extent, sub-pixel impervious surface change (ISC), and vertical structure at national to global scales. First, an innovative multi-level object-based texture classification approach was adopted to overcome spectral confusion between urban and nonurban land cover types. It was designed to be robust and computationally affordable. This method was applied to the 2010 Global Land Survey Landsat data archive to produce a global urban extent map. An initial assessment of this product yielded over 90% overall accuracy and good agreement with other global urban products for the European continent. Second, for sub-pixel ISC mapping, the uncertainty caused by seasonal and phenological variations is one of the greatest challenges. To solve this issue, I developed an iterative training and prediction (ITP) approach and used it to map the ISC of entire India between 2000 and 2010. At 95% confidence, the total ISC for India between 2000 and 2010 was estimated to be 2274.62±7.84 km2. Finally, using an object-based feature extraction approach and the synergy of Landsat and freely available elevation datasets, I produced 30m building height and volume maps for England, which for the first time characterized urban vertical structure at the scale of a country. Overall, the height RMSE was only ±1.61 m for average building height at 30m resolution. And the building volume RMSE was ±1142.3 m3. In summary, based on innovative data processing and information extraction methods, this dissertation seeks to fill in the knowledge gaps in urban science by advancing the fine scale characterization of global urban extent, change, and structure. The methods developed in this dissertation have great potentials for automated monitoring of global urbanization and have broad implications for assessing the environmental impact, disaster vulnerability, and long-term sustainability of urbanization

Elektrochemisches Korrosionsverhalten von Nietverbindungen in Hybridbauweise

In dieser Arbeit wurde das elektrochemische Korrosionsverhalten von zwei Nietverbindungen in Hybridbauweise untersucht. Auf der Grundlage von elektrochemischen Polarisationsversuchen der Nietkomponenten sowie durch Simulation mit der Methode der Finiten Elemente konnte das Korrosionsverhalten für den gefügten Zustand abgeleitet werden. Das Korrosionsverhalten für den gefügten Zustand wurde aus der grafischen Analyse der erhaltenen Stromdichte-Potential-Kurven abgeleitet. Zudem wurde in der Simulation ein kritischer Abstand für galvanisch induzierte Lochkorrosion auf der Aluminiumlegierung berechnet. Das grafisch abgeleitete sowie das berechnete Korrosionsverhalten wurden für beide Nietverbindungen im Experiment bestätigt. Weiterhin wurde ein systemspezifischer Werkstoffparameter mit einer neuentwickelten Analysemethode extrahiert und dessen Abhängigkeit von der Expositionszeit der Nietverbindungen in dem Klimawechseltest nach VDA 621-415 und dem VDA 621-414 Freibewitterungstest untersucht