The existing theoretical and empirical literature to investigate the existence of local market power is typically based on spatial competition models in the tradition of Hotelling's (1929) linear city and Salop's (1979) circular city. In models of this kind, strong assumptions are made that lead to a spatial homogeneity (symmetry) of firms in a highly stylized one-dimensional market space. However, some of these assumptions are hardly satisfied in many (retail) markets. The present thesis builds on a recent model by Chen and Riordan (2007), in which the market is characterized by a star-shaped graph with a central intersection. In an extension of Chen and Riordan, I distinguish between firms close to the center and firms in the periphery of a spatial market. This spatial heterogeneity leads to an asymmetric competition between firms. A central firm directly competes with a larger number of firms than remote firms do. The implications of the theoretical model are tested in two empirical applications to the retail gasoline market of Vienna and Austria. Using station level data on diesel prices, I estimate price reaction functions for gasoline stations in two different approaches. In the first approach the Austrian retail gasoline market is divided into numerous highly localized and delimited markets. The second approach analyzes the metropolitan area of Vienna and treats the whole market as one big network of gasoline stations, which are connected through the road network. In both approaches I apply econometric spatial autoregressive (SAR) models. The estimated parameters of the slopes of the reaction functions are used to evaluate the impact of individual gasoline stations on equilibrium market prices depending on their location within the market (network). All results obtained provide evidence for (more) central suppliers serving as a stronger reference in pricing than (rather) remote suppliers. Thus, the assumption of a symmetry in spatial competition which is usually implied by spatial competition models in theoretical and applied research, is rejected. (author's abstract)

We empirically investigate the importance of centrality (holding a central position in a spatial network) for strategic interaction in pricing for the Austrian retail gasoline market. Results from spatial autoregressive models suggest that the gasoline station located most closely to the market center - defined as the 1-median location - exerts the strongest effect on pricing decisions of other stations. We conclude that centrality influences firms' pricing behavior and further find that the importance of centrality increases with market size. (authors' abstract) / Series: Department of Economics Working Paper Series

published_or_final_version / Urban Planning and Environmental Management / Doctoral / Doctor of Philosophy

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Controlled Auto-Ignition (CAI) also known as Homogeneous Charge Compression Ignition (HCCI) is increasingly seen as a very effective way of lowering both fuel consumption and emissions. Hence, it is regarded as one of the best ways to meet stringent future emissions legislation. It has however, still many problems to overcome, such as limited operating range. This combustion concept was achieved in a production type, 4-cylinder gasoline engine, in two separated tests: naturally aspirated and turbocharged. Very few modifications to the original engine were needed. These consisted basically of a new set of camshafts for the naturally aspirated test and new camshafts plus turbocharger for the boosted test. The first part of investigation shows that naturally aspirated CAI could be readily achieved from 1000 to 3500rpm. The load range, however, decreased noticeably with engine speed due to flow restrictions imposed by the low lift camshafts. Ultra-low levels of NOx emissions and reduced fuel consumption were observed. After baseline experiments with naturally aspirated operation, the capability of turbocharging for extended CAI operation was investigated. The results show that the CAI range could achieve higher load and speed with the addition of the turbocharger. The engine showed increased fuel consumption due to excessive pumping losses. Emissions, however, have been reduced substantially in comparison to the original engine. NOx levels could be reduced by up to 98% when compared to a standard SI production engine.

We highlight the importance of "centrality" for pricing. Firms characterized by a more central position in a spatial network are more powerful in terms of having a stronger impact on their competitors' prices and on equilibrium prices. These propositions are derived from a simple theoretical model and investigated empirically for the retail gasoline market of Vienna, Austria. We compute a measure of network centrality based on the locations of gasoline stations in the road network. Results from a spatial autoregressive model show that prices of gasoline stations are more strongly correlated with prices of central competitors.

Submitted in fulfillment of the requirements of the degree of Master of Engineering, Durban University of Technology, Durban, South Africa, 2016. / Separation processes in the chemical process industries is dependent on the science of chemical thermodynamics. In the field of chemical separation process engineering, phase equilibrium is a primary area of interest. This is due to separation processes such as distillation and extraction which involves the contacting of different phases for effective separation. The focal point of this research project is the measurement and modeling of binary vapour-liquid equilibrium (VLE) phase data of systems containing ether-alcohol organic compounds. The VLE data were measured with the use of the modified apparatus of Raal and Mühlbauer, (1998). The systems of interest for this research arose from an industrial demand for VLE data for systems containing ether-alcohol organic compounds. This gave rise to the experimental VLE data isotherms being measured for the following binary systems: a) Methyl tert-butyl ether (1) + 1-pentanol (2) at 317.15 and 327.15 K b) Methyl tert-butyl ether (1) + 2, 2, 4-trimethylpentane (2) at 307.15, 317.15 and 327.15K c) 2, 2, 4-Trimethylpentane (1) + 1-pentanol (2) at 350.15, 360.15 and 370.15K d) Diisopropyl ether (1) + 2,2,4-trimethylpentane (2) at 320.15, 330.15 and 340.15K e) Diisopropyl ether (1) + 1-propanol (2) at 320.15, 330.15 and 340.15K f) Diisopropyl ether (1) + 2-butanol (2) at 320.15, 330.15 and 340.15K The data for all the measured binary systems investigated at these temperatures are currently not available in the open source literature found on the internet and in library text resources. The systems were not measured at the same temperatures because certain system isotherm temperatures correlate to a pressures above 1 bar. This pressure of 1 bar is the maximum operating pressure specification of the VLE apparatus used in this project. The experimental VLE data were correlated for model parameters for both the  and methods. For the method, the fugacity coefficients (vapour-phase non-idealities) were tabulated using the virial equation of state and the Hayden-O’Connell correlation (1975); chemical theory and the Nothnagel et al. (1973) correlation method. The activity coefficients (liquid phase non-idealities) were calculated using three local-composition based activity coefficients models: the Wilson (1964) model, the NRTL model (Renon and Prausnitz, 1968); and the UNIQUAC model (Abrams and Prausnitz, 1975). Regarding the direct method, the Soave-Redlich-Kwong (Redlich and Kwong, 1949) and Peng-Robinson (1976) equations of state ii were used with the temperature dependent alpha-function (α) of Mathias and Copeman (1983) with the Wong-Sandler (1992) mixing rule. Thermodynamic consistency testing, which presents an indication of the quality and reliability of the data, was also performed for all the experimental VLE data. All the systems measured showed good thermodynamic consistency for the point test of Van Ness et al. (1973) - the consistency test of choice for this research. This however, was based on the model chosen for the data regression of a particular system. Therefore, the combined method of VLE reduction produced the most favourable results for the NRTL and Wilson models. / M

Why did China choose certain policy over others that would achieve similar impact? Because China has a significant presence in the modern international community, it is difficult yet critical to understand the policy implications of the Chinese government under its unique political and socioeconomic context. This thesis shows the impact of a specific “price floor” policy China chose to employ in its oil and gasoline market, and identifies the factors concerning the Chinese regime that it took into consideration in the decision making process, through analysing data and official statements released by the government. After different parties affected by this policy are recognized, this thesis investigate how those impacts relate back to the Chinese government’s long-term agenda of energy security and environmental protection.

The dynamics of demand for energy goods such as gasoline are complicated by investment decisions and behavioral habits. Both types of complication can be captured by a habits model, in which past consumption enters into an agent's current utility function. If the agent is forward-looking, or 'rational', then habits imply his consumption of the habit-forming good will be sensitive to his expectation of future market conditions, in particular future prices. This sensitivity implies, in turn, that demand and price elasticity will depend upon price volatility, and that the agent will respond differently to different types of price changes. Price elasticity measured over the mixture of price changes that occur in a given market will therefore underestimate the power of policy instruments that act through permanent or long-run price changes. This thesis examines the implications of rational habits on demand behavior in a multi-good setting, drawing motivation from and considering applications to gasoline demand. Chapter 1 introduces the theory of rational habits, examines a simple perfect-foresight model, and uses microeconometric techniques to look at an application to U.S. gasoline demand. Chapter 2 builds a theory model in which agents have rational habits and future prices are uncertain. The implications of this model are then utilized in Chapter 3, which uses macro-type econometric techniques to test for rational habits in international gasoline demand. The empirical evidence suggests that rational habits may indeed shape demand for gasoline and that traditionally-measured price elasticity should not be used to project consumers' responses to policy interventions.