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Dissertation
Development and assessment of volume resolving velocimetry for turbomachinery test facilities
(Deutsches Zentrum für Luft- und Raumfahrt DLR, 2017-12-21)
The present thesis assesses the applicability of volume resolving velocimetry
for turbo machinery test facilities. Tomographic particle image velocimetry has been implemented in a transonic cascade wind tunnel. Assessment is based on 3D-3C measurements of the passage vortex in an axial compressor cascade at subsonic inflow (Ma1=0.6). Results show broad consistency with stereoscopic PIV with improved depth resolution. A novel Fast Multiplicative Algebraic Reconstruction Technique (FMART) enables signi cantly faster ...
Dissertation
Residual-Layer-Free 3D Nanoimprinting using Novel Hybrid Soft Templates
(2017-08-23)
Hybrid 3D soft templates are designed and evaluated for residual layer free 3D imprinting in UV-Substrate Conformal Imprint Lithography (SCIL). 3D imprinting usually results in laterally varying residual layers, which cannot be removed by conventional etching processes in a satisfactory manner. The hybrid templates introduced in this thesis are hybrid in a way that their template protrusions are enclosed with a UV-blocking metal layer, by this means selective UV curing of the resist material is attainable. Hence, the ...
Dissertation
Optical Sensor Array based Nanospectrometer: Fabrication of high resolution 3D NanoImprint master templates and bonding of Fabry-Pérot filter array onto photodetector array
(2017-05-11)
In the field of optical spectroscopy, spectrometers are high resolution optical sensors that have emerged as a platform for a wide range of application fields. Commercially available spectrometers are bulky and expensive. Hence, this limits its integration into modern mobile and wearable devices. To overcome this limitation, miniaturization of spectrometers is an interesting target for a wide range of emerging applications. The most attractive concept of fabricating miniaturized spectrometers is the Fabry-Pérot filter ...