This study presents results from tail pipe emissions of particulate matter from a turbocharged common rail 2-stroke marine diesel engine (4RTX-3 from Wärtsilä) investigated at various operating conditions and using two different fuels. Size distributions were measured with a SMPS (Scanning Mobility Particle Sizer). A thermodesorber (TD) was applied to remove volatile material. In addition, filter samples were taken for gravimetric and chemical analysis. The mean diameters of the particles ranged between 20-40 nm, which is considerably smaller than the diameter of particles known from 4-stroke diesel engines as used in cars. A TD operated at 400 • C evaporated the majority of the particles. The particle mass is dominated by volatile organic material, the fraction of which is significantly higher than for engines in cars. A high nucleation mode was found instead of a pronounced accumulation mode as known from 4-stroke diesel engines.

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The undulatory swimming dynamics of the millimetric nematode Caenorhabditis elegans was investigated in fluids with di↵erent viscosities. The technique of micropipette deflection was used to directly measure the drag forces experienced by the swimming worm in both the lateral and propulsive directions. Gait modulation due to increasing viscosity in our tethered system was found to be qualitatively similar to that of freely swimming worms. Resistive force theory was used to determine the drag coe cients of the slender swimmer, and the experimental values were compared to the classical theories of Lighthill as well as Gray and Hancock. The gait modulation was shown to be independent of how the environmental resistance is changed, indicating the relevance of only the fluid resistance on the swimming kinematics and dynamics of the nematode.

Particle emissions from four spark ignition engines were measured during steady state and transient chassis dynamometer tests. Transient Unified Drive Cycle tests were conducted at 0 °C and room temperature. Particle number, size distribution, active surface area, and photoelectric activity were determined. The results generally show low emission values for steady state operation of the warm engine. High particle concentrations are emitted in the first phase of the highspeed steady state testing. Once the engine is warmed up high emissions mainly occur during transient operation phases. The formation of nucleation mode particles is favored by the low concentration of carbonaceous soot, which offers volatile material little surface area for condensation.