Dynamics of mobile ions in glass - What do conductivity spectra tell us ?

In glassy electrolytes, the diffusive motion of the mobile ions consists of thermally activated hops from site to site. Beyond this statement, little is known about the microscopic dynamics of ionic transport in glass, the problems originating mainly from the lack of long-range order. An important step forward has been made recently by employing the technique of conductivity spectroscopy in a frequency range that covers about fourteen decades, extending up to the far infrared. This particular experimental tool acts as a "microscope in time" resolving hopping processes down to the sub-picosecond time regime. The power of the method is exemplified for the case of a lithium-ion conducting lithium bromide-lithium borate glass, which is representative in many respects. Among the results obtained is the frequent oecurrence of correlated back-and-forth hopping processes as well as the finding that ions have preferences for optimally configured sites which play the role of stepping stones for translational diffusion

Biofuel production in South Africa: the games, the cost of production and policy options

The production of biofuels in South Africa has evolved very slowly and at present there are only a handful of plants producing some derivative of biofuel. The lack of commitment from government and the utter information distortion under which the current policy framework was developed have largely contributed to the current state of affairs. The manner in which the current policy framework was formulated based on the available information has impacted negatively on the development of the industry and it is hypothesised that had a better and more comprehensive analysis process been followed, the framework would be of such a nature that the industry could be sustainable in the long run. The study examines the policies and policy development process that have taken place in other biofuel producing countries and investigates the various policy instruments that are in use in these industries. The study further explores the interactions of industry role players at both government and producer level while attempting to explain the factors that could have caused their deviation from the rational and expected path of strategies and actions. In both games, each at a different level, the resultant Nash Equilibrium changes and prevailing strategies indicate that it is not in the role player's interest to commit to the industry. The government departments involved in formulating the biofuel policy seem to be uninformed and hence choose a low support route while oil companies consistently choose not to invest in capacity and biofuel refiners find their Nash Equilibrium at high levels of investment. A decision tree is formulated to conduct an in-depth review of the current level of profitability of proposed and current projects with specific reference to current legislation. The decision tree unpacks the current economic environment in the industry and identifies various factors that are crucial to the long-term development and growth of the industry. Based on this comprehensive survey of the industry and a detailed comparison of various production costs, together with the design of the game theoretic framework, a conceptual policy framework is designed and it is proposed that this replaces the current biofuel strategy. The new policy framework establishes its sustainable structure based on facts, detailed figures and existing project information. The framework is based on a more sustainable policy structure that combines elements of rural development with the economics that are required in order for the industry to be sustainable in the long run. Unlike the official government biofuels policy, the Industrial Biofuels Strategy, this proposed policy framework takes the industry's and role players' requirements into account and is designed in such a way that government targets and goals are accomplished. It is hypothesised that the implementation of this comprehensive policy framework will assist in the establishment of a successful and sustainable biofuels industry. CopyrightThesis (DCom)--University of Pretoria, 2010.Agricultural Economics, Extension and Rural Developmentunrestricte

From farm to retail : costs and margins of selected food industries in South Africa

This dissertation highlights the need for a formal methodology to be developed in order to unpack complicated supply chains and to publish information that explains how the farm value or farm to retail price spread of certain products can be calculated and how these results are to be analysed. It is for this reason that the study reviews and applies the methodology used for the calculation of price spreads and farm values. It applies the methodology to five food supply chains of maize, fresh milk, beef, poultry and sugar. The analysis of farm values and spread has already been developed in an international context but it has not of yet been applied in the South African context. It is therefore the aim of this dissertation to illustrate how this methodology can be applied here and how this can be done on a continuous basis. The main objectives of the study are: To review and apply the methodology used for the calculation of price spreads and farm value, as well as to analyse trends of five agricultural commodities in the food sector. To understand not so much on what is behind the previous rise in food prices, but rather on why; when the farm or producer prices fall, do retail prices on certain goods not fall by the same margin? The question that needs to be asked is who or what is responsible for this? A detailed analysis of the supply chain of various products could prove invaluable in the process of understanding price movements. To investigate the degree of transparency of information in the South African food sector is investigated by looking at the market share that the various supermarket chains hold. Since competition and concentration of role players within this sector of the economy plays such a vital role in the determination of the market’s fairness, it is important that the size and the percentage of market share that the retailers hold in the market is researched and understood. A special section focuses on the market share that some retailers hold as a percentage share of the entire supermarket retail sector. To discuss the estimation of the specific cost incurred, at various levels,within the maize-to-maize meal and beef-to-beef products supply chains, in detail. This involves designing a framework for the continuous analysis of food prices and costs contained within these two supply chains and understanding the costs incurred by the different role players. In applying the methodology to estimate farm value and farm to retail price spread it is determined some of the commodities such as beef, milk and sugar experienced a slight widening of the farm to retail price spread, while the opposite occurred with the price spread of maize meal and broiler meat. A widening farm to retail price spread shows that farmers’ share in terms of the retail price is declining and as a result their share of the final product has become less. Farmers in the beef, milk and sugar sectors experienced this while maize and chicken farmers experienced the opposite, in other words a narrowing spread and as a result they are earning more of the final product. In applying the various econometric tests in order to test for asymmetric price behaviour in the various supply chains it was found that in four of the five supply chains the transmission of increases in producer prices where not smoothly and timely transmitted to the retail price. The models that fared worst in the analyses were those of the sugar, beef, fresh milk and a part of the maize supply chain. The inabilities of the models to show any form of significance, even when tested economic theory is applied indicate that something is amiss within the supply chains. Asymmetric price transmissions, a lack of accurate data or unjust market behaviour by role players within the supply are some of the factors that could be responsible for this. The analysis in chapter 5 is based on these findings. A proposed framework for an in depth analysis of such a supply chain is documented there. The detailed analysis of costs and margins in the maize to maize meal and beef supply chains, have shown that there are many stages along the supply chain, where various costs and profits can have severe influences. In chapter 5 a detailed analysis has been done on this with the objective of developing a framework that can be applied to an industry. This chapter lends specific detail as to where the influences of such costs can be the greatest. The results point out that, of the five supply chains, only two of them, namely chicken and maize (from farm gate to miller), adhered to some form of economic theory, whereas the other three either suffered from insignificant/unrepresentative data or actual price transmission asymmetry. On the basis of this, the supply chains of both super maize meal and the five selected beef cuts were unpacked with the profit margin and the role player’s cost of formation at the different levels within the value chains. A conclusion can be made that parts of the maize supply chain (milldoor to retailer), the beef supply chain, the sugar supply chain and the dairy supply chain all suffer from asymmetric price transmissions or alternatively, a data discrepancy. This conclusion is drawn from the fact that the Error Correction Models ECMs for these specific industries failed most of the diagnostic tests and contained some insignificant variables. The diagnostic tests did not only test for misspecification but included a standard procedure, using the Jarque Bera test for normality, the ARCH LM test for heteroscedasticity, the White test for heteroscedasticity as well as the Breusch Godfrey test for serial correlation. The fact that the ECMs of these supply chains had these problems does give rise to a concern as to the transmission of prices within some of the supply chains within the South African food industry. The applied methodology used in unpacking of the supply chains, was applied with the aim of developing a framework that can be adapted and used for similar analyses in future. The aim of this methodology was solely on developing and applying a methodology to two of the five supply chains, partly based on the results in chapter 4 but also on the importance of the commodities in the South African food industry, and to illustrate, by using real data, how this framework can benefit future research.Dissertation (MCom(Agric Economics))--University of Pretoria, 2006.Agricultural Economics, Extension and Rural Developmentunrestricte

Development of a GEM-TPC prototype

The use of GEM foils for the amplification stage of a TPC instead of a con- ventional MWPC allows one to bypass the necessity of gating, as the backdrift is suppressed thanks to the asymmetric field configuration. This way, a novel continuously running TPC, which represents one option for the PANDA central tracker, can be realized. A medium sized prototype with a diameter of 300 mm and a length of 600 mm will be tested inside the FOPI spectrometer at GSI using a carbon or lithium beam at intermediate energies (E = 1-3AGeV). This detector test under realistic experimental conditions should allow us to verify the spatial resolution for single tracks and the reconstruction capability for displaced vertexes. A series of physics measurement implying pion beams is scheduled with the FOPI spectrometer together with the GEM-TPC as well.Comment: 5 pages, 4 figures, Proceedings for 11th ICATTP conference in como (italy

Beamline-Instrumentierung und Experimentautomatisierung fuer ROBL an der ESRF/Grenoble (F)

Durch das Forschungszentrum Rossendorf wurde in den Jahren 1996-1998 ein eigenes Strahlrohr fuer Experimente mit Synchrotronstrahlung an der ESRF (European Synchrotron Radioation Facility) in Grenoble/Frankreich aufgebaut. Das Strahlrohr verfuegt ueber zwei alternativ nutzbare Messplaetze fuer die Untersuchung von radioaktiven Proben mittels Roentgenabsorptionsspektroskopie und fuer Materialstrukturuntersuchungen mit Roentgendiffraktion. Der Bericht konzentriert sich auf die Arbeiten, die fuer die Steuerung der Optik und die Nutzung der Messplaetze hinsichtlich der Elektronik, Rechentechnik und Software erforderlich waren. Nach einer Beschreibung der Randbedingungen und einer Kurzcharakteristik der geraetetechnischen Basis werden wichtige Hardwarekomponenten fuer die Instrumentierung der Systeme vorgestellt. Die rechentechnische Basis wird anschliessend beschrieben. Die angewendeten Software-Grundprinzipien werden erlaeutert und diskutiert sowie an einigen Applikationen beispielhaft verdeutlicht. Abschliessend werden spezifische Probleme bei der Programmierung von Applikationen mit grafischer Bedienoberflaeche in Verbindung mit Geraetezugriffen behandelt. Tabellen, in denen die benutzten Hardware-Module und die Softwarekomponenten zusammengestellt sind, ermoeglichen einen Ueberblick ueber das Gesamtsystem. Das Literaturverzeichnis dient als Leitfaden fuer die Detaildokumentationen

Non-Human and Human Transport to Mars: by Mars- plus Europa-INPPS Flagship Missions including High Mass Science Payload

Summary Status INPPS Flagshi

Mars- plus Europa-INPPS Flagship Missions with High Power Electric Thrusters and Heavy Science Payload

2020/2021 orbit calculations (DLR Bremen + MAI Moscow): 3 Orbits for one non-human MARS/EUROPA-INPPS flagship 1. Orbit Earth (11 Oct 2026) => Mars (28 Jan 2028); 2. Orbit Mars (22 Sept 2028) => Earth (29 Jul 2029); 3. Orbit Earth (12 Oct 2031) => Jupiter / Europa (6 Dec 2035) 22 ETs (for the INPPS flagship CET): example - gridded CET plate with combined ET