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In the dual membrane fuel cell (DM-Cell), protons formed at the anode and oxygen ions formed at the cathode migrate through their respective dense electrolytes to react and form water in a porous composite layer called dual membrane (DM). The DM-Cell concept was experimentally proven (as detailed in Part I of this paper). To describe the electrochemical processes occurring in this novel fuel cell, a mathematical model has been developed which focuses on the DM as the characteristic feature of the DM-Cell. In the model, the porous composite DM is treated as a continuum medium characterized by effective macro-homogeneous properties. To simulate the polarization behavior of the DM-Cell, the potential distribution in the DM is related to the flux of protons and oxygen ions in the conducting phases by introducing kinetic and transport equations into charge balances. Since water pressure may affect the overall formation rate, water mass balances across the DM and transport equations are also considered. The satisfactory comparison with available experimental results suggests that the model provides sound indications on the effects of key design parameters and operating conditions on cell behavior and performance.
The combination of fossil-derived fuels with ethanol and methanol has acquired relevance and attention in several countries in recent years. This trend is strongly affected by market prices, constant geopolitical events, new sustainability policies, new laws and regulations, etc. Besides bio-fuels these materials also include different additives as anti-shock agents and as octane enhancer. Some of the chemical compounds in these additives may have harmful properties for both environment and public health (besides the inherent properties, like volatility). We present detailed Raman spectral information from toluene (C7H8) and ethanol (C2H6O) contained in samples of ElO gasoline-ethanol blends. The spectral information has been extracted by using a robust, high resolution Fourier-Transform Raman spectrometer (FT-Raman) prototype. This spectral information has been also compared with Raman spectra from pure additives and with standard Raman lines in order to validate its accuracy in frequency. The spectral information is presented in the range of 0 cm-1 to 3500 cm-1 with a resolution of 1.66cm-1. This allows resolving tight adjacent Raman lines like the ones observed around 1003cm-1 and 1030cm-1 (characteristic lines of toluene). The Raman spectra obtained show a reduced frequency deviation when compared to standard Raman spectra from different calibration materials. The FT-Raman spectrometer prototype used for the analysis consist basically of a Michelson interferometer and a self-designed photon counter cooled down on a Peltier element arrangement. The light coupling is achieved with conventional62.5/125μm multi-mode fibers. This FT-Raman setup is able to extract high resolution and frequency precise Raman spectra from the additives in the fuels analyzed. The proposed prototype has no additional complex hardware components or costly software modules. The mechanical and thermal disturbances affecting the FT-Raman system are mathematically compensated by accurately extracting the optical path information of the Michelson interferometer. This is accomplished by generating an additional interference pattern with a λ = 632.8 nm Helium-Neon laser (HeNe laser). It enables the FT-Raman system to perform reliable and clean spectral measurements from the materials under observation.
Durch eine stetige Preissteigerung der fossilen Energieträger werden auch im Bereich der mobilen Arbeitsmaschinen neben einer hohen Zuverlässig u.a. Forderungen nach steigenden Gesamtwirkungsgraden, mit der hierdurch einhergehenden Energieeffizienz, forciert. Auch bei mobilen Arbeitsmaschinen ist der häufig eingeschränkt zur Verfügung stehende Bauraum für Traktionsantriebe eine Herausforderung. Ziel dieser Veröffentlichung ist ein allgemeingültiger Vergleich verschiedener elektrischer Antriebsarten als Traktionsantrieb für mobile Arbeitsmaschinen.
The increased complexity and dynamics of the business environment and the problems of a young organization are treated extensively in the literature [Bleicher 2002, p. 34; Malik 1996, p. 86; Ulrich/Probst 1990, p. 23ff; Gomez 1999, p. 65]. This complexity is the core of the leadership role in a company [Malik 1996, p. 184]. STÜTTGEN (1999, p. 8) states in this regard: "A satisfactory answer to the question, according to which patterns complex social systems are to be designed to meet the proliferating environmental complexity facing an adequate intrinsic complexity of the company can be, in this context, a critical success factor for management." How can young SMEs solve strategic problems with service engineering in their companies?
A 2002 study on corporate planning of the top German companies measured by turnover found that of the surveyed large companies, 80 percent have carried out strategic planning and 90 percent have operational planning in place [Link/Orbán 2002, pp. 11]. The human and material costs of designing and implementing the strategic planning can be very high. Many SMEs do not have the necessary capacities to do this. To obtain a comprehensive overview, this chapter examines the existing studies and findings for young SMEs. Many of the studies reviewed and the following publications relate to SMEs as defined by the EU. This analysis also includes established SMEs and medium-sized enterprises.
Various Rapid Prototyping methods have been available for the production of physical architectural models for a few years. This paper highlights in particular the advantages of 3D printing for the production of detailed architectural models. In addition, the current challenges for the creation and transfer of data are explained. Furthermore, new methods are being developed in order to improve both the technical and economic boundary conditions for the application of 3DP. This makes the production of models with very detailed interior rooms possible. The internal details are made visible by dividing the complex overall model into individual models connected by means of an innovative plug-in system. Finally, two case studies are shown in which the developed methods are applied in order to implement detailed architectural models. Additional information about manufacturing time and costs of the architectural models in the two case studies is given.