2004, Wondraczek, Lothar, Heide, Gerhard, Frischat, Günther Heinz, Khorsandi, Alireza, Willer, Ulrike, Schade, Wolfgang

Emerging techniques of mid-infrared absorption spectroscopy offer potentially great sensitivity and selectivity for combustion control and emission monitoring. Beeause of that, a differenee frequency based mid-infrared absorption spectrometer has been considered for application in the glass industry. Based on preliminary tests within laboratory conditions, a spectrometer which operates at wavelengths around 5 μm was applied to online monitoring of the atmosphere of a gas fired glass melting furnace. The CO concentration was measured in order to demonstrate the feasibility of a mid-infrared absorption spectrometer for process control in the glass industry. Α series of measurements was performed in situ as well as crossing the recuperator entry, resulting in general advice on the construction of a prototype device.

2003, Wondraczek, Lothar, Frischat, Günther Heinz, Heide, Gerhard, Weidenfeller, Bernd, Ziegmann, Gerhard

Due to differenees in thermal expansion, crazing and delamination effects are observed in multiphase materials such as glasspolymer composites. For a composite consisting of spherical particles homogeneously embedded in a matrix phase, the radial and tangential stresses occurring have been simulated. Two-dimensional calculations were used as a basis for optimizing the optical transparency of the material which was found to be strongly affected by the mechanical properties of the constituents of the composite and the resulting stresses. Further, the influence of the shape and the size distribution of the particles on the emergence of scattering surfaces inside the material is described. With the Christiansen-Shelyubskii method the maximum transparency of a potential material depending on whether it is a gradient material or not can be predicted.

2004, Wondraczek, Lothar, Heide, Gerhard, Frischat, Günther Heinz, Khorsandi, Alireza, Willer, Ulrike, Schade, Wolfgang

Laser spectroscopic diagnostics of combustion species at elevated temperature has shown considerable progress during the last years and decades. Particularly, techniques of mid-infrared absorption spectroscopy using fundamental rotational/vibrational transitions offer potentially great sensitivity and selectivity for combustion control. However, applications are still limited to mostly laboratoryscale investigations, which is mainly due to drawbacks of light sources and beam guidance materials. On the other band, many efforts are made to facilitate industrial application. In this context, the relevance of mid-infrared absorption spectroscopy for in situ monitoring of minor species in glass melting furnaces is obvious, too. The present paper gives a general review of available techniques and their impact on emission diagnostics in the glass industry, considering conventional as well as emerging light sources, detectors, peripheral devices and spectroscopic techniques.