In‐Situ‐Charakterisierung optischer Mehrschichtsysteme in Großflächen‐ Produktionsanlagen

The paper discusses approaches to the insitu analysis of optical multi‐layer coating stacks such as mirror coatings, AR coatings or lowE layer stacks on large‐area substrates in production environments. The stable production of complex layer systems requires in‐situ analysis systems that are able to provide spectral information and optical performance data, but also yield thickness information for individual layers and thus aide the operating staff in detailed analyzing deviations from the production target stack. Solutions incorporating in‐situ optical reflectance, transmittance and ellipsometry measurements wi^th optical data being collected not only for the completed layer stack, but also at intermediate coating stages, are discussed and the accuracy, robustness and stability of different measurement systems and computation strategies are compared.     

Prospects of gas supply until 2020 in Europe and its relevance for the power sector in the context of emission trading

With the liberalization of energy markets and the introduction of an emission trading system, electricity production by gas combined cycle power plants has significantly increased in the European Union in recent years. Reasons for the significant increase include the short construction time for gas power plants and the favourable investment costs. One further advantage is the relatively low CO₂ emissions of gas power plants. Thus, a key option for reducing emissions is seen in the increased use of gas for power production. Model calculations from various models show that an increase of gas power production is expected. In general, however, the interdependencies of the different markets (gas, electricity and CO₂) as well as the country-specific gas supply options, determined by pipelines and liquefied natural gas (LNG), are neglected. As the competitiveness of gas power plants mainly depends on the availability of gas and the gas price, a novel model that integrates electricity, gas, and CO₂- emission markets assuming perfect competition will be presented. The objective of this paper is to analyse the long-term relevance of the gas market for the electricity sector in the European Union in the context of CO₂-emission reduction targets.     

Hintergründe zur Nutzlastabminderung nach DIN 1055‐3

Background of Load Reduction according to DIN 1055‐3 The present study focuses on possibilities of load reduction according to DIN 1055‐3. The respective code regulations will be presented as well as the outcome of the investigation concerning imposed loads in domestic buildings. The results are representative for the load variability of imposed loads and may be applied to other building categories.     

Querkraftwiderstand betonstabbewehrter Bauteile ohne Querkraftbewehrung

Shear Strength of Concrete Elements reinforced by prestressed Concrete Bars The shear strength of commonly reinforced concrete elements without shear reinforcement has been extensively studied and several semi‐empirical approaches for the determination of ultimate shear loads have been published. It seems to be necessary to prove the validity of these approaches for concrete elements reinforced with materials with a bi‐linear stress‐strain diagram in the elastic range. Prestressed Concrete Bars (PCB) show a distinct non‐linear behavior after decompression. Thus, they are especially suitable for a comparison with common reinforcement. The present article describes tests on the shear strength of concrete elements reinforced with PCBs. The results obtained are compared with the code DIN 1045‐1.     

Achieving Water Quality System Reliability Using Genetic Algorithms

This paper presents an efficient approach for obtaining wasteload allocation solutions that provide the optimal trade-off between treatment cost and reliability. This approach links a genetic algorithm (GA) with the first-order reliability method (FORM) for estimating the probability of system failure under a given wasteload allocation. The GA-FORM optimization approach is demonstrated for the case study of managing water quality in the Willamette River in Oregon. The objective function minimizes the sum of the treatment cost and the penalty associated with breaching a reliability target for meeting a water quality standard. The random variables used to generate the reliability estimates include streamflow, temperature, and reaeration coefficient values. The results obtained indicate that the GA-FORM approach is nearly as accurate as the approach that links the GA with Monte Carlo simulation and is far more efficient. The trade-off between total treatment cost and reliability becomes more pronounced at higher water quality standards and is most sensitive to the uncertainty in the reaeration coefficient. The sensitivity to the reaeration coefficient also increases at increased reliability levels.     

Forecasting Cyanobacterial Concentrations Using B-Spline Networks

Artificial neural networks have been used successfully in a number of areas of civil engineering, including hydrology and water resources engineering. In the vast majority of cases, multilayer perceptrons that are trained with the back-propagation algorithm are used. One of the major shortcomings of this approach is that it is difficult to elicit the knowledge about the input/output mapping that is stored in the trained networks. One way to overcome this problem is to use B-spline associative memory networks (AMNs), because their connection weights may be interpreted as a set of fuzzy membership functions and hence the relationship between the model inputs and outputs may be written as a set of fuzzy rules. In this paper, multilayer perceptrons and AMN models are compared, and their main advantages and disadvantages are discussed. The performance of both model types is compared in terms of prediction accuracy and model transparency for a particular water quality case study, the forecasting (4 weeks in advance) of concentrations of the cyanobacterium Anabaena spp. in the River Murray at Morgan, South Australia. The forecasts obtained using both model types are good. Neither model clearly outperforms the other, although the forecasts obtained when the B-spline AMN model is used may be considered slightly better overall. In addition, the B-spline AMN model provides more explicit information about the relationship between the model inputs and outputs. The fuzzy rules extracted from the B-spline AMN model indicate that incidences of Anabaena spp. are likely to occur after the passing of a flood hydrograph and when water temperatures are high.     

Ingenieuranalyse von Erdbebenschäden: Das Bingöl (Türkei)‐Erdbeben vom 1. Mai 2003

Engineering analysis of earthquake damage: The Bingöl (Türkiye) earthquake of May 1, 2003. Through the engineering analysis of structural damage caused by the magnitude 6.6 Bingöl (Türkiye) earthquake on May 1, 2003, an attempt is made to work out the damage‐promotive factors. The damage analyses, instrumental site investigations, and the reinterpretation of structural behaviour concentrate on reinforced‐concrete buildings which were documented on site. At this, standardized school buildings take center stage, showing different grades of damage (slight damage to total collapse) even though they are of comparable character. A scheme to evaluate the causes of structural damage will be introduced which accounts for ground motion intensity, resonance effects between site und structure, directional effects of the seismic wave propagation, as well as for features of design and construction. Besides to phenomena and typical damage pattern which had been already be observed after other worldwide earthquakes, factors will be emphasized (possibly) contributing to the amplification of seismic ground motion. This in particular concerns topographical peculiarities which even seem to be insufficiently considered by actual code provisions. Furthermore, a reinforced‐concrete frame structure, typical for the regarded region, will be subjected to the nonlinear static “pushover” analysis in order to check the plausibility between recorded ground motion of the damaging mainshock and observed structural performance, the latter to be represented by the actual state of damage pattern. A methodical procedure will be presented which can be applied to derive statements on the structural vulnerability by stiffness‐dependent capacity curves. This being mainly based on material parameters and reinforcement detailing to be documented on site.     

PARTICLE SHAPE AND STRUCTURE ANALYSIS FROM THE SPATIAL INTENSITY PATTERN OF SCATTERED LIGHT USING DIFFERENT MEASURING DEVICES

The spatial intensity pattern of scattered light from nonspherical particles was investigated numerically and experimentally in order to obtain—beside size—sensitive shape information. The discrete dipole approximation (DDA) was used to calculate the light scattering pattern for some basic types of particle shapes. From these calculations the lower size limit where shape information can successfully be detected from light scattering was found at a size parameter of approximately 1. It can be even lower if elongated particles (cylinders) are present. For the exemplary studies three different laboratory instruments available to the authors were utilized.

The comparison of experimental and numerical results yielded good correlations, which confirmed the selected theoretical approach. Thus, it is possible to develop experimental setups for specific applications only on basis of theoretical data. From the experiments we found that azimuthal scattering at a constant scattering angle is a promising setup for shape characterization, which can be adapted to specific applications with high flexibility. For supermicron particles the surface structure also contributes to the scattering pattern provided the characteristic size of surface elements substantially exceeds the wavelength of the light source.