Ein optoanalytisches Verfahren zur Bestimmung der Faserverteilung und ‐orientierung in stahlfaserverstärktem UHFB

An Optoanalytic Method for the Determination of the Distribution and Orientation of Fibres in Steel Fibre Reinforced UHPC Micro steel fibres were often used to improve the ductility as well as to increase the tensile and bending strength of ultra high performance concrete (UHPC). The knowledge about the distribution and orientation of fibres is important to predict the load capacity of structures made of fibre reinforced UHPC. It is also relevant from economic and ecological point of view. Due to the multiplicity of influences, such as geometry, concrete properties and manufacture technology, it is necessary to investigate the distribution and orientation of fibres for individual application. At Leipzig University a practicable method was developed to determine the distribution and orientation of micro steel fibres in UHPC.     

Standardplanung versus Simulationen – wirtschaftlicher Nutzen höherwertiger Planungswerkzeuge am Beispiel der Sanierung des Festsaales im Palmengarten Frankfurt

Standardized planning process versus computer simulation analysis – the economical benefit of high tech planning tools. Currently the usual planning process according to the German Honorarordnung für Architekten und Ingenieure (HOAI) is splitted strictly into several disciplines with different, specific planning tools being used in each workscope. In the technical disciplines simplifying steady state calculation methods (simple table algorithms) are used very often by reasons of tradition and reduction of work. In the beginning this article makes evident – by an example from practice – that modern, sophisticated planning tools like computer simulations are always superior to the standard tools. Then the enormous savings during the design process of a mechanical ventilation plant, which can be obtained by using simulation technics, is shown by an example from reality. Finally the cost effectiveness of simulations is evaluated and thus also the financial benefits of using computer simulations during planning process is quantified exemplarily.     

Zur Aussagekraft von Simulationsergebnissen auf Basis der Testreferenzjahre (TRY) über die Häufigkeit sommerlicher Überhitzung

Frequency of overheating during the summer – How meaningful are simulation results based on test reference years? Thermal comfort during the summer is becoming an increasingly important quality characteristic of modern office buildings. With attention increasingly also focusing on sustainability considerations, designs for such buildings are often based on passive ventilation without air‐conditioning or mechanical ventilation. The design and assessment of such energy‐saving indoor climate concepts is based on peak room temperatures and the frequency of overheating during the summer, usually involving (zonal) thermal simulation software. The calculation of overheating frequencies requires meteorological data for a whole year, in Germany usually in the form of original test reference years (TRYs) provided by Deutscher Wetterdienst (DWD), Germany's National Meteorological Service. However, these TRYs were developed for other purposes and tend to represent hot spells during the summer inadequately. In addition, TRYs do not take into account urban heat islands or the effects of climate change observed since the 1990 (with increasing tendency). Frequencies of high room temperatures during the summer determined using the original TRYs are therefore unrealistically low and unsuitable as a basis for decisions relating to climate concepts. For more realistic overheating frequency calculations it is advisable to use TRYs incorporating extreme summers and perhaps weather data for future years, which will shortly be made available by meteorologists.     

Regionalisierte Darstellung der Nitratbelastung im Grundwasser Niedersachsens

Grundwasser - Zur Nitratbelastung im Grundwasser besteht aufgrund der intensiven Agrarwirtschaft in Niedersachsen ein besonderer Informationsbedarf. Die Auswertung von Punktdaten soll...     

Regional development and the value of migratory labor-some perverse economic/technological interactions

It has long been agreed, that the economic value of unemployed labor is less than its wage rate. Shadow-pricing of such labor is common practice in economic analysis. The usual outcome of such shadow-pricing is that the economic rate of return of a project is enhanced. But this is not always the case. Using the data from a soil productivity enhancement project in Mexico, it is shown that the use of essential, labor-saving technology in a project designed to increase output and Income may reduce, rather than increase economic benefits, if the displaced labor has no alternative employment opportunities, while the opposite is the case if such alternatives exist.     

Adaptive band-pass equalizer for multiple carrier data transmission

In this paper, a novel band-pass equalizer for orthogonal multiple carrier (omc) data receivers is investigated. Essentially, the band-pass equalizer consists of an fir filter preceding the receiver filter bank and processing the whole transmission band at the high input sampling rate. The coefficients of the fir equalizer are optimized iteratively in the sense of a minimum mean square error of the received and demodulated signals. A simulation of the proposed equalizer on a work-station shows that it adapts in a substantially shorter time compared to adaptive multichannel baseband equalizers at a comparable computational efficiency.