Biometrie am BBI — Chancen und Randbedingungen

Der Betreiber eines Verkehrsflughafens muss Bereiche, die nicht allgemein zug?nglich sind, gegen unberechtigten Zugang sichern und darf, soweit es sich um sicherheitsempfindliche Bereiche handelt, den Zugang nur berechtigten Personen gestatten. Der Flughafenbetreiber gibt dazu an die Zutrittsberechtigten Ausweise aus, mit denen diese sich beim Betreten des Sicherheitsbereiches authentifizieren müssen. Für den neuen Flughafen Berlin-Brandenburg International BBI wird auf den Ausweisen wegen der stark wachsenden Anzahl der zu überprüfenden Personen als zus?tzliches Authentifizierungselement eine biometrische Referenz gespeichert. Bei der Auswahl des biometrischen Verfahrens sind die besonderen Bedingungen von Verkehrsflugh?fen in Betracht zu ziehen.     

Dynamic Min-Max Problems

In this paper a method to check the solvability of a set of linear equations in the (max, min, +) algebra is described. Then, extensions to dynamic (or periodic) systems in the (max, min, +) algebra are provided. Further, some results regarding the uniqueness of solutions in both cases are given. Finally, we address a more general quasi periodic problem and provide an algorithm for its solution.     

A Silicon Nanocrystal Schottky Junction Solar Cell produced from Colloidal Silicon Nanocrystals

Solution-processed semiconductors are seen as a promising route to reducing the cost of the photovoltaic device manufacture. We are reporting a single-layer Schottky photovoltaic device that was fabricated by spin-coating intrinsic silicon nanocrystals (Si NCs) from colloidal suspension. The thin-film formation process was based on Si NCs without any ligand attachment, exchange, or removal reactions. The Schottky junction device showed a photovoltaic response with a power conversion efficiency of 0.02%, a fill factor of 0.26, short circuit-current density of 0.148 mA/cm², and open-circuit voltage of 0.51 V.     

Shark Skin Inspired Riblet Coatings for Aerodynamically Optimized High Temperature Applications in Aeroengines

The shark skin effect is the mechanism of wall friction reduction of a fluid due to a riblet structured surface. A new application for riblet surfaces may be jet engine blades. Riblet structured coatings on the blades would act as oxidation protection and additionally reduce the skin drag on the surface. In this study structuring surface areas of high temperature nickel‐based alloys is investigated. These alloys are used for compressor and turbine blades near the combustion chamber. Experiments are performed by depositing titanium on a nickel base alloy through particular metal grids using magnetron sputtering. For single‐digit micrometer structures, photolithography with subsequent electrodeposition of nickel as well as sputter deposition and thermal evaporation of several materials are investigated. Successfully fabricated structures are oxidized at 900–1 000 °C for up to 100 h and the resulting shape is characterized using scanning electron microscopy. The most accurate structures are obtained using photolithography and subsequent electrodeposition. The reduction of the wall shear stress was measured in an oil channel. The riblet structures prior to oxidation show a reduction of the wall shear stress of up to 4.9%.     

Impact of Condensates Containing Chloride and Sulphate on the Corrosion in Automotive Exhaust Systems

The chemical composition of condensates recovered from a test car was systematically analysed in this study. It was found that most condensates contain a higher concentration of chloride than that of sulphate. In order to understand the effect of sulphate on the pitting behaviour of 436SS and to predict whether pitting will occur in these condensates, pitting potentials were determined in a 0.2M sulphate solution with varying chloride concentration by using the potentiodynamic cyclic polarization curve method. The results demonstrate that sulphate prevents pitting initiation of 436SS when the concentration of sulphate is higher than that of chloride. However, no inhibitory effect of sulphate was observed when the sulphate concentration is lower than the chloride concentration. As the condensate recovered from the muffler contains more chloride than sulphate, the muffler is most likely suffering from pitting. This was confirmed by the microscopic observation of the corroded muffler from the test car.     

Damage tolerance investigations on rails

The paper summarises damage tolerance investigations on railway rails which the authors have carried out in the context of the German-French joint project NOVUM (novel methods for quantitative prediction of rail performance at increased service loads) [Girardi L, Heyder R, Dider L, Boulanger D. IDR2-NOVUM promises lower rail maintenance costs. Railway Gazette Int 2005;(July):439-41[1]]. The investigations include the determination of the crack driving force as a function of the various loading components a rail is subjected to and the simulation of residual lifetime. Features such as the local load input at the rail-wheel interface, dynamic effects and statistical aspects of crack resistance are explicitly taken into account.     

Policies to support renewable energies in the heat market

Whereas the contribution from renewable energies in the electrical power market is increasing rapidly, similar progress in the heat market is yet to be made. A prerequisite for progress is the development of innovative support instruments that transcend the usual support through public subsidies or tax reductions. We present an overview of the various classes of possible instruments. Some particularly interesting instruments will be selected and evaluated, comparing them qualitatively and quantitatively for the case of Germany. The most favourable model is found to be a new, allocation-financed¹ model known as the Bonus Model. This model will be described in more detail.     

An improved assay for the determination of phospholipase C activity

Phospholipases C (PLC, EC 3.1.4.3) are enzymes that specifically hydrolyze the C‐O‐P bond in phospholipids, yielding sn‐1,2(2,3)‐diacylglycerides and the phosphate residue bearing the corresponding headgroup. The biochemical characterization of PLC requires methods for the reliable determination of their activity. Here, an assay is described in which the phosphate residue released by the PLC is cleaved with an alkaline phosphatase. The phosphate formed is then extracted with n‐butanol and quantified as phosphomolybate complex. The applicability of this method is demonstrated for a concentration range from 10 nM to 10 mM for a range of phospholipids bearing different headgroups in an aqueous and a two‐phase system. The method has the additional advantage that the crude enzyme can be used without the need for purification.