Hollow cathode sputtering system - installation, operation and theoretical background

The objective of this work was to assemble, install and operate a hollow cathode sputtering system (HCSS). Therefore a complex vacuum system was built to create the right sputtering environment. The purpose of the HCSS is to develop advanced thin conducting oxides (TCOs) as well as high resistivity transparent (HRT) layers which are used for thin film photovoltaic technology, particularly cadmium telluride based and copper indium gallium selenide based solar cells. A theoretical background of the thin film technology and a comparison of different deposition methods in regards to the sputtering process is provided. Thereby, an in-depth investigation of zinc oxide (ZnO), tin oxide (SnO2), and cadmium stannate (Cd2SnO4) is presented. Furthermore, the operating characteristics of a hollow cathode are described. A detailed analysis of the different system components, as well as their functions, is thoroughly elucidated. Moreover, important system parameters required for the correct operation of the HCSS are identified

Anderson localization through Polyakov loops: lattice evidence and Random matrix model

We investigate low-lying fermion modes in SU(2) gauge theory at temperatures above the phase transition. Both staggered and overlap spectra reveal transitions from chaotic (random matrix) to integrable (Poissonian) behavior accompanied by an increasing localization of the eigenmodes. We show that the latter are trapped by local Polyakov loop fluctuations. Islands of such "wrong" Polyakov loops can therefore be viewed as defects leading to Anderson localization in gauge theories. We find strong similarities in the spatial profile of these localized staggered and overlap eigenmodes. We discuss possible interpretations of this finding and present a sparse random matrix model that reproduces these features.Comment: 11 pages, 23 plots in 11 figures; some comments and references added, some axis labels corrected; journal versio

A concept for quantitative characterization of the air balance in Bavarian forest soils

Site-specific descriptions of soil water balance and soil air balance are important for tree species selection in forestry. We present a concept for describing the soil air balance for Bavaria. It is an enhancement of an empirical multiple linear regression model that explains soil oxygen deficiency in terms of topographic, climate and soil parameters. We modelled numerous combinations of site conditions with the hydrologic model LWF-Brook 90 to determine an estimator for soil oxygen deficiency. This estimator reflects water logging that persists for a certain length of time. In a second step we will develop a new regression model and combine this information with topographical information about additional water fluxes in a GIS. We aim to combine both steps in order to describe the air balance of forest soils for the entirety of Bavaria.Da neben der Beschreibung des Wasserhaushaltes auch die Kenntnis über Luftmangel für die standortgerechte Baumartenwahl wichtig ist, wird ein Konzept für die bayernweite Beschreibung des Lufthaushaltes vorgestellt. Es ist eine Weiterentwicklung eines empirischen Regressionsmodells, das die Staunässe mittels Geländeparametern, Klima und Bodendaten abschätzt. Dazu wurden mit dem Wasserhaushaltsprogramm LWF-Brook 90 zahlreiche Kombinationen von Standortsfaktoren simuliert und eine Schätzgröße für Luftmangel ausgegeben. Diese Größe beschreibt die Einschränkung des Lufthaushaltes über einen längeren Zeitraum. In einem weiteren Schritt wird dieser deterministische Luftmangelparameter über ein neues Regressionsmodell abgeleitet und mit zusätzlichen topographischen Informationen über Zu- und Abflüsse in einem GIS kombiniert. Ziel ist es, für ganz Bayern den Lufthaushalt von Waldböden zu beschreiben

Electricity powering combustion: hydrogen engines

Hydrogen is ameans to chemically store energy. It can be used to buffer energy in a society increasingly relying on renewable but intermittent energy or as an energy vector for sustainable transportation. It is also attractive for its potential to power vehicles with (near-) zero tailpipe emissions. The use of hydrogen as an energy carrier for transport applications is mostly associated with fuel cells. However, hydrogen can also be used in an internal combustion engine (ICE). When converted to or designed for hydrogen operation, an ICE can attain high power output, high efficiency and ultra low emissions. Also, because of the possibility of bi-fuel operation, the hydrogen engine can act as an accelerator for building up a hydrogen infrastructure. The properties of hydrogen are quite different from the presently used hydrocarbon fuels, which is reflected in the design and operation of a hydrogen fueled ICE (H2ICE). These characteristics also result in more flexibility in engine control strategies and thus more routes for engine optimization. This article describes the most characteristic features of H2ICEs, the current state of H2ICE research and demonstration, and the future prospects

Cost-effectiveness of caries excavations in different risk groups − a micro- simulation study

Background Whilst being the most prevalent disease worldwide, dental caries is increasingly concentrated in high-risk populations. New caries treatments should therefore be evaluated not only in terms of their cost-effectiveness in individuals, but also their effects on the distribution of costs and benefits across different populations. To treat deep caries, there are currently three strategies: selective (one-step incomplete), stepwise (two-step incomplete) and complete excavation. Building on prior research that found selective excavation generally cost-effective, we compared the costs-effectiveness of different excavations in low- and high-risk patients, hypothesizing that selective excavation had greater cost-effectiveness-advantages in patients with high compared with low risk. Methods An average tooth-level Markov-model was constructed following the posterior teeth in an initially 18-year old male individual, either with low or high risk, over his lifetime. Risk was assumed to be predicted by several parameters (oral hygiene, social position, dental service utilization), with evidence-based transition probabilities or hazard functions being adjusted for different risk status where applicable. Total lifetime treatment costs were estimated for German healthcare, with both mixed public-private and only private out-of-pocket costs being calculated. For cost-effectiveness-analysis, micro-simulations were performed and joint parameter uncertainty introduced by random sampling of probabilities. Cohort analyses were used for assessing the underlying reasons for potential differences between strategies and populations. Results Selective excavation was more effective and less costly than both alternatives regardless of an individual’s risk. All three strategies were less effective and more costly in patients with high compared with low risk, whilst the differences between risk groups were smallest for selective excavation. Thus, the cost-effectiveness- advantages of selective excavation were more pronounced in high-risk groups, who also benefitted the most from reduced private out-of-pocket treatment costs. Conclusions Whilst caries excavation does not tackle the underlying sources for both the development of caries lesions and the potential differences of individuals’ risk status, selective excavation seems most suitable to treat deep lesions, especially in patients with high risk, who over-proportionally benefit from the resulting health-gains and cost-savings

Individualized Muscle-Tendon Assessment and Training

The interaction of muscle and tendon is of major importance for movement performance and a balanced development of muscle strength and tendon stiffness could protect athletes from overuse injury. However, muscle and tendon do not necessarily adapt in a uniform manner during a training process. The development of a diagnostic routine to assess both the strength capacity of muscle and the mechanical properties of tendons would enable the detection of muscle-tendon imbalances, indicate if the training should target muscle strength or tendon stiffness development and allow for the precise prescription of training loads to optimize tendon adaptation. This perspective article discusses a framework of individualized muscle-tendon assessment and training and outlines a methodological approach for the patellar tendon.Peer Reviewe