Möglichkeiten zur Wasserstoff-Erzeugung mit verminderter Kohlendioxid-Emission für zukünftige Energiesysteme

Hydrogen production possibilities for future energy systems with reduced carbon dioxide emission. All possible hydrogen production methods which are of technical importance or could become technically important have been systematically classified. The conventional processes based on fossil raw materials, as well as hydrogen production from biomass, are considered with a view to the separation of CO₂ or the minimization of CO₂ emission by using nuclear energy or solar energy, or by using electric energy generated from these primary energies. In addition, possibilities of hydrogen production with carbon separation are investigated. The nonfossil processes using thermal, electric or radiation energy are treated briefly, and water electrolysis is described in more detail. Finally, the hydrogenation of fossil raw materials is discussed, which would lead to mixed carbon-hydrogen energy systems.     

Motion estimation in beating heart surgery

Minimally invasive beating-heart surgery offers substantial benefits for the patient, compared to conventional open surgery. Nevertheless, the motion of the heart poses increased requirements to the surgeon. To support the surgeon, algorithms for an advanced robotic surgery system are proposed, which offer motion compensation of the beating heart. This implies the measurement of heart motion, which can be achieved by tracking natural landmarks. In most cases, the investigated affine tracking scheme can be reduced to an efficient block matching algorithm allowing for realtime tracking of multiple landmarks. Fourier analysis of the motion parameters shows two dominant peaks, which correspond to the heart and respiration rates of the patient. The robustness in case of disturbance or occlusion can be improved by specially developed prediction schemes. Local prediction is well suited for the detection of single tracking outliers. A global prediction scheme takes several landmarks into account simultaneously and is able to bridge longer disturbances. As the heart motion is strongly correlated with the patient's electrocardiogram and respiration pressure signal, this information is included in a novel robust multisensor prediction scheme. Prediction results are compared to those of an artificial neural network and of a linear prediction approach, which shows the superior performance of the proposed algorithms.     

Cryogenic far-infrared laser absorptivity measurements of the Herschel Space Observatory telescope mirror coatings

Far-infrared laser calorimetry was used to measure the absorptivity, and thus the emissivity, of aluminum-coated silicon carbide mirror samples produced during the coating qualification run of the Herschel Space Observatory telescope to be launched by the European Space Agency in 2007. The samples were measured at 77 K to simulate the operating temperature of the telescope in its planned orbit about the second Lagrangian point, L2, of the Earth-Sun system. Together, the telescope's equilibrium temperature in space and the emissivity of the mirror surfaces will determine the far-infrared-submillimeter background and thus the sensitivity of two of the three astronomical instruments aboard the observatory if stray-light levels can be kept low relative to the mirror emission. Absorptivities of both clean and dust-contaminated samples were measured at 70, 118, 184, and 496 microm. Theoretical fits to the data predict absorptivities of 0.2-0.4% for the clean sample and 0.2-0.8% for the dusty sample, over the spectral range of the Herschel Space Observatory instruments.     

Ground-based imaging differential optical absorption spectroscopy of atmospheric gases

We describe a compact remote-sensing instrument that permits spatially resolved mapping of atmospheric trace gases by passive differential optical absorption spectroscopy (DOAS) and present our first applications of imaging of the nitrogen dioxide contents of the exhaust plumes of two industrial emitters. DOAS permits the identification and quantification of various gases, e.g., NO2, SO2, and CH2O, from their specific narrowband (differential) absorption structures with high selectivity and sensitivity. With scattered sunlight as the light source, DOAS is used with an imaging spectrometer that is simultaneously acquiring spectral information on the incident light in one spatial dimension (column). The second spatial dimension is scanned by a moving mirror.     

Optical Nuclear Polarization of Deuterium Spins: Mechanisms and Applications in Solid State NMR

A gain in detection sensitivity of more than three orders of magnitude has been achieved in high resolution solid state ²H NMR of monocrystalline systems by applying optical nuclear polarization (ONP) via excited triplet states. The method is demonstrated for crystals of fluorene doped with optically active guest molecules which have localized triplet states and for the 1 : 1 mixed crystal of anthracene/tetracyanobenzene with excitonic states. The factors determining the efficiency of ONP are discussed and compared to the case of proton spin systems.     

Research in school psychology in the Federal Republic of Germany.

Discusses school psychology research recently reported in the Federal Republic of Germany. Literature appears to be dominated by three trends with a fourth emerging. Trends discussed include (1) the need to be able to deal with children from foreign countries who bring a diversity of languages, skills, and customs to the classroom, (2) parental involvement in education and the family systems approach, and (3) investigation of approaches to delivery of services, organizational development, and the role of the school psychologist. Little distinction is made between consultation and counseling. An emerging trend, provision of services in adult education, is beginning to show research interest. All of these trends reflect an emphasis on practical rather than theory-oriented research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Ein neuer Ansatz zur Bestimmung theoretischer Obergrenzen für das zweidimensionale orthogonale homogene Packproblem

Zusammenfassung Zur Lösung des zweidimensionalen homogenen Packproblems, das in der Logistik z. B. bei der lagenweisen Paletten-Beladung mit quaderförmigen Packstücken gleicher Größe, bei der Beladung von LKW und Containern und beim Füllen von Standardbehältern auftritt, sind keine exakten Algorithmen mit polynomiell begrenzter Zeitkomplexität bekannt. Zur Lösung dieser Problemstellung wird deshalb auf heuristische Verfahren zurückgegriffen. Die Optimalität der heuristisch ermittelten Lösungen kann durch die Bestimmung einer theoretischen Obergrenze für die Anzahl der Packstücke überprüft werden. In diesem Beitrag werden verschiedene Verfahren zur Bestimmung theoretischer Obergrenzen vorgestellt und hinsichtlich ihrer Güte analysiert. Daran anschließend wird ein neuer Ansatz zur Verbesserung der Obergrenzenbestimmung unter Einsatz dieser Verfahren dargestellt. Dieser Ansatz basiert auf der Ausnutzung der Struktur-Eigenschaften des betrachteten Packproblems.