Understanding China’s past and future energy demand: an exergy efficiency and decomposition analysis

There are very few useful work and exergy analysis studies for China, and fewer still that consider how the results inform drivers of past and future energy consumption. This is surprising: China is the world’s largest energy consumer, whilst exergy analysis provides a robust thermodynamic framework for analysing the technical efficiency of energy use. In response, we develop three novel sub-analyses. First we perform a long-term whole economy time-series exergy analysis for China (1971–2010). We find a 10-fold growth in China’s useful work since 1971, which is supplied by a 4-fold increase in primary energy coupled to a 2.5-fold gain in aggregate exergy conversion efficiency to useful work: from 5% to 12.5%. Second, using index decomposition we expose the key driver of efficiency growth as not ‘technological leapfrogging’ but structural change: i.e. increasing reliance on thermodynamically efficient (but very energy intensive) heavy industrial activities. Third, we extend our useful work analysis to estimate China’s future primary energy demand, and find values for 2030 that are significantly above mainstream projections

FRET and ligand related NON-FRET processes in single quantum dot-perylene bisimide assemblies

Nanoassemblies are formed viaself-assembly of ZnS capped CdSequantum dots (QD) and perylene bisimide dyes (PBI). Upon assembly formation with functionalized dye molecules the QD photoluminescence (PL) is quenched. Quenching has been assigned partly to FRET (fluorescence resonance energy transfer) and NON-FRET processes. By means of time resolved single particle spectroscopy of immobilized QD-dyeassemblies, it is demonstrated that NON-FRET processes are due to new non-radiative decay channels caused by the assembly formation process itself. Immobilized (single) assemblies exhibit the same processes as ensembles of assemblies in toluene solution. Only one dye molecule on a QD quenches the PL up to 50%, which is much stronger than is expected when replacing a volume related number of ligands. NON-FRET processes are distinct from photoinduced charge and/or energy transfer. A combination of a Stern-Volmer and FRET analysis of ensemble experiments supports the investigation of the dynamics of assembly formation at extremely low concentration ratios of PBI to QD. This allows us to distinguish between the effects of PBI and ligands on PL quenching on a single molecule level which is not possible in conventional ligand dynamic experiments

Investigation of the Wake Mixing Process Behind Transonic Turbine Inlet Guide Vances with Trailing Edge Coolant Flow Ejection

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Stroemungsfeldmessungen an einem Turbinenrotorgitter bei starker Abweichung vom Auslegungspunkt (Vorhaben 1.440A). Stroemungsfeldmessungen an einem ebenen Gitter sowie je einem stehenden und rotierenden Ringgitter bei starker Abweichung vom Auslegungspunkt (Vorhaben 1.440B) Schlussbericht

In einer Turbine liegen derart komplexe Stroemungsverhaeltnisse vor, dass selbst in einer einstufigen Maschine zur experimentellen und theoretischen Analyse der Stroemungsvorgaenge die Anwendung vereinfachter Modelle unerlaesslich ist. Fortschritte in der Rechnertechnologie ermoeglichen es heute realistische (reibungsbehaftete) Konfigurationen zu untersuchen. Dieser in Zukunft zunehmende Einsatz numerischer Verfahren kann nur nach vorheriger umfangreicher Validierung an ausgewaehlten Testfaellen erfolgen. Bei der Berechnung von Stroemungen mit Abloesegebieten (auch lokalen) werden die Anwendungsgrenzen heutiger Rechenverfahren deutlich. In diesen rein experimentell orientierten TURBOTECH Vorhaben 1.440 A und 1.440 B wurden umfangreiche Untersuchungen bei Stroemungszustaenden, die deutlich vom Auslegungspunkt abweichen, durchgefuehrt; die Festlegung der zu untersuchenden Stroemungszustaende erfolgte in enger Anlehnung an die bereits vorhandenen Daten aus dem TURBOTECH Vorhaben 1.1.1.7. Es wurden Stroemungszustaende ausgewaehlt, bei denen bereits im Bereich der Schaufelvorderkante Abloeseblasen auftreten. Die hier gewonnenen Daten ergaenzen sehr gut die Datenbasis aus dem Vorhaben 1.1.1.7 und stellen weitere Testfaelle dar, mit denen die Anwendungsgrenzen von Rechenverfahren ermittelt werden koennen. Im Windkanal wurden die gleichen Leit-und Laufradgitter untersucht, wie im Vorhaben 1.1.1.7. Zunaechst wurden die 2-D Messungen bei deutlich saug- bzw. druckseitiger Zustroemrichtung sowohl in inkompressibler als auch in transsonischer Stroemung durchgefuehrt. Es stehen Nachlauf-, Druckverteilungs-, Grenzschicht- und Waermeuebergangsmessungen sowie LDA-Messungen zur Verfuegung. Bei den 3-D Messungen wurde schwerpunktmaessig der Einfluss der Variation der Abstroemmachzahl untersucht, da Zustroemwinkelvariationen garnicht oder nur sehr eingeschraenkt moeglich sind. Es stehen Nachlauf-, Druckverteilungs- und Grenzschichtmessungen sowie L2F-Messungen zur Verfuegung. (orig.)Because of very complex flow conditions even in single stage machines there is a need for simple models when analysing flow phenomena experimentally as well as theoretically. Progress in computer technology renders it possible to investigate realistic (viscous) configurations. Due to the increasing application of numerical codes it is necessary to validate these codes using selected test cases. When computing flow fields including separation - even local ones - the application limits of todays computer codes are reached. Therefore the experimental TURBOTECH research programmes 1.440 A and 1.440 B were established to investigate off-design flow conditions. The flow fields to be investigated were defined with respect to the data collected within the TURBOTECH research programme 1.1.1.7 concerning design conditions. Flow fields including a (small) separation bubble just downstream of the leading edge are of major interest. The data collected here complete the design flow field data and in addition there are some more test cases to detect the range of application of numerical flow field computation. Measurements were performed using the same rotor cascade and the same stator cascade already investigated within the above mentioned programme 1.1.1.7. First of all 3-D measurements were done variing the inlet flow direction; data from wake transverses, from pressure distributions on the blade surface, from boundary layer measurements and from heat transfer measurements as well as from LDA-measurements are available. For the 3-D measurements emphasis was put on the variation of the downstream Mach number, because of the very restricted possibilities varying the inlet flow direction. Data from wake traverses, from pressure distributions on the blade surface and from boundary layer measurements as well as from L2F-measurements are available. (orig.)Also published as DLR-IB 223-96A55SIGLEAvailable from FIZ Karlsruhe / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman