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Thermographic measurements of a high-speed cutting process have been performed with an infrared camera. To realize images without motion blur the integration times were reduced to a few microseconds. Since the high tool wear influences the measured temperatures a set-up has been realized which enables small cutting lengths. Only single images have been recorded because the process is too fast to acquire a sequence of images even with the frame rate of the very fast infrared camera which has been used. To expose the camera when the rotating tool is in the middle of the camera image an experimental set-up with a light barrier and a digital delay generator with a time resolution of 1 ns has been realized. This enables a very exact triggering of the camera at the desired position of the tool in the image. Since the cutting depth is between 0.1 and 0.2 mm a high spatial resolution was also necessary which was obtained by a special close-up lens allowing a resolution of app. 45 microns. The experimental set-up will be described and infrared images and evaluated temperatures of a titanium alloy and a carbon steel will be presented for cutting speeds up to 42 m/s.

A fiber optic two-color pyrometer has been developed at the Institute of Heat Transfer and Air Conditioning at RWTH Aachen to measure temperatures at surfaces with low emissivities with a high time and space resolution. A fused silica fiber is used to transmit the radiation to the pyrometer from measuring positions with limited optical access. The two-color principle allows accurate measurements of absolute temperatures of surfaces with unknown emissivities if the assumption of a gray body behavior at the measurement wavelengths is valid. The minimum temperature which can be measured with the pyrometer is limited due to the small radiation energy at low temperatures given by Planck's law, the emissivity of the body and the size of measurement area. At present temperatures of low emissivity metallic surfaces with sizes of 0.4 mm can be measured down to 250 degree(s)C. A new application to measure temperatures during high speed turning required a time resolution above the maximum of 2 microsecond(s) . To enhance the time resolution of the pyrometer the electronics was modified and a 30 MHz data acquisition board has been applied to the system. With this configuration a nanosecond time resolution is possible but the minimum measurable temperature increases. Different aspects for the limitation of the time resolution will be discussed. A new set-up with a nanosecond spark-flashlight will be described for the test of the transient response of the pyrometer and some test measurements will be presented.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A numerical method is developed to solve the Navier-Stokes equations for laminar compressible flow around delta wings. A large-scale solution on a mesh of 129 x 49 x 65 points for transonic flow Moo = 0.85, a = 10 deg, and Re*>,cR = 2.38 X 10 around a 65 deg swept delta wing with round leading edge is presented and discussed. The results reveal the presence of primary, secondary, and even tertiary vortices. Comparison with experiment shows that the interaction between the primary and secondary vortices is obtained correctly and that these results are a more realistic simulation than the one given by the Euler equations.

We present numerous applications of the recently developed dual-focus fluorescence correlation spectroscopy (2fFCS) to the measurement of translational diffusion of proteins and protein complexes. The method is applied to measuring Ca2+-binding curves of wild-type and mutant of the proteins calmodulin and recoverin. 2fFCS is also capable of quantifying the conformational flexibility of macromolecular complexes, which is exemplified on the peptide binding of the major histocompatibility complex I (MHC I). Furthermore, we extended 2fFCS to measure fluorescence correlation at the nanosecond time scale, allowing also for measuring rotational diffusion. We performed a comparative study of translational and rotational diffusion (and related hydrodynamics size) of proteins, and present results for several globular proteins (BSA, human serum albumin, aldolase, ovalbumin). In all cases, measurements are performed at pico- to nanomolar sample concentrations, and with an accuracy of determining hydrodynamic size of a few percent. For performing 2fFCS measurements, a protein or protein complex needs only unspecific fluorescent labeling which is easily accomplished with commercially available dyes. Thus it is hoped that 2fFCS becomes a widely used and easy to handle technique in biophysical research.References1. Dertinger T.; Loman A.; Ewers B.; Muller C.B.; Kramer B.; Enderlein J., Opt. Expr.16, 2008, 14353-14368.2. Muller C.B.; Loman A.; Pacheco V.; Koberling F.; Willbold D.; Richtering W.; Enderlein J., Eur. Phys. Lett.83, 2008, 46001.3. Dertinger T.; Pacheco V.; von der Hocht I.; Hartmann R.; Gregor I.; Enderlein J., ChemPhysChem8, 2007, 433-443.