a post-processing method was developed and qualified to determine a quantity proportional to the heat transfer coefficient into the flow. By plotting this quantity for each pixel of the surface, a qualitative, two-dimensional heat transfer map was obtained. The results clearly depicted the areas of onset and end of transition over the full span of the model and agreed with the expected behavior based on the respective flow condition. To validate the approach, surface hotfilm measurements were conducted simultaneously on the same NACA profile. Both techniques showed excellent agreement. The temperature decline method allows to visualize laminarturbulent transitions on static or moving parts and can be applied on a very broad range of scales-from tiny airfoils up to large airplane wings.

Abstract. An all-electrical torque differential magnetometry (also known as cantilever magnetometry) setup employing piezoelectric quartz tuning forks is demonstrated. The magnetometer can be operated under ambient conditions as well as low temperatures and pressures. It extends the allowed specimen mass range up to several 10 µg without any significant reduction in the sensitivity. Operation under ambient conditions and a simple all-electrical design of the magnetometer should allow for an easy integration with other experimental setups. The uniaxial magnetic anisotropy of a 25 µm diameter iron wire, measured under ambient conditions with a high signal to noise ratio, was found to be in good agreement with its literature value. Further applications of the technique are discussed.

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Optical remote sensing of phytoplankton draws on distinctive spectral features which can vary with both species and environmental conditions. Here, we present a set-up (ENVILAB) for growing phytoplankton under well-defined light, temperature and nutrient conditions. The custom-built light source enables creation of light with spectral composition similar to natural aquatic environments. Spectral tuning allows for light quality studies. Attenuation is monitored with a spectrometer in transmission mode. In combination with automated spectrophotometer and fluorimeter measurements, absorption and excitationemission-fluorescence spectra are recorded. The set-up opens the door for systematic studies on phytoplankton optical properties and physiology. References and links1. P. Falkowski, "Ocean Science: The power of plankton," Nature 483(7387), S17-S20 (2012). 2. P. G. Falkowski, "The role of phytoplankton photosynthesis in global biogeochemical cycles," Photosynth. Res. 235-258 (1994). 39(3),