Although graphitic carbon has been known and used as a biomaterial for a very long time, the excellent biocompatibility of diamond-like carbon (DLC) films has been addressed only in a few cases. We anticipate the combination of bioinert DLC films and surface-immobilized bioactive biomolecules with antithrombogenic properties, such as the polysaccharide heparin, as a straightforward concept to optimize the haemocompatibility of a wide variety of materials. Therefore, to assess this property in view of an application as vascular grafts, surface analytical studies on DLC-coated and heparinized polymer and silicon substrates were performed. The DLC films were deposited on polytetrafluoroethylene (PTFE), PTFE vascular prostheses, polystyrene and silicon wafers by an energetic acetylene plasma beam and subsequently exposed to an ammonia plasma before heparin was covalently coupled to such functionalized surfaces by an end-point attachment method. The biochemical characterization by thrombin tests revealed, in accordance with XPS measurements, a high amount of heparin on the surface and an extended blood coagulation time. Thus, the efficiency of the plasma treatment for functionalization and successful improvement of the haemocompatibility of DLC films could be shown. Figure 5. Thrombin activity of various DLC-coated and heparinized substrate materials in dependence on the exposure time in an ammonia plasma beam prior to heparin immobilization. In comparison to the pure and DLC-coated substrates, including the control material (a commercial PTFE vascular graft), an enhanced antithrombogenic activity can be observed for exposure times >30 s.

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The introduction of quiet short take-off and landing for civil aircraft operations in close proximity to the population poses important technological challenges. One critical aspect is the realization of extreme lift augmentation at low acoustic emissions. The aircraft concept selected to achieve this goal is a high-lift system equipped with an active flow-control non-slotted flap and a droop nose. For this specific configuration, trailing edge noise becomes a dominant noise source. Porous materials as a passive means for trailing-edge noise reduction are selected and characterized. Results of extensive experimental investigations in the acoustic wind tunnel Braunschweig are presented and discussed to point out the potential and limitations of the selected porous devices. Practical issues related to material manufacturing and integration into the wind tunnel model are addressed. The noise reduction potential of passive porous trailing-edge devices is found to strongly depend on both these aspects. Issues related to the characterization of the porous materials properties are described. Although porous materials are found to be successful at reducing trailing-edge noise emissions, the results indicate that there is still a need for more generic investigations to further clarify the parametric dependencies between noise reduction and material properties.

Novel plate‐type heat exchangers (HXs) with high‐power densities are proposed based on novel integrated flow channel designs. Net‐shape plates were achieved by the molding of powder mixtures to wood‐based composites (WBC's). HX stacks are built by plate‐to‐plate joining followed by pyrolysis and silicon melt infiltration. The C/SiSiC provided with PyC–SiC coating was gas‐tight to helium up to 5.5 MPa. Corrosion tests with coupons were performed using a ternary eutectic fluoride salt (FLiNaK) as the intermediate heat transfer fluid. While SiC is vulnerable to corrosion by the salt, the coating offers a high degree of protection to the ceramic substrate.

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