Ventilation of passenger car cabins: comparison of experimental data and numerical calculations

The complex flow in the interior of a passenger car cabin is measured and calculated in a Reynolds number range of practical importance. It turns out that the mean flow field compares quite well, even in minor details. But, experiments and calculations deviate considerably as far as turbulent quantities are concerned. The situation is analysed by a closer look to the physics of the flow field. From this, conclusions are drawn why the k−ɛ model applied here might be inappropriate for the flow field under consideration.     

Screening, Nonadiabaticity, and Quantized Acoustoelectric Current

Quantized single-electron transport driven by surface acousticwaves (SAW) through a pinched-off narrow constriction isstudied theoretically. Long-range Coulomb interaction causesthe tunneling coupling between the two-dimensional electrongas (2DEG) and the moving minimum of the SAW-induced potentialto decay rapidly with time. The energy scale /,associated with the characteristic time of this decay ,controls both the width of the transition regions between theplateaus and the slope of the plateaus. This sets a limit forthe accuracy of the quantization of acoustoelectric current atlow temperature.     

Gaseous and particulate emissions from prescribed burning in Georgia

Prescribed burning is a significant source of fine particulate matter (PM2.5) in the southeastern United States. However, limited data exist on the emission characteristics from this source. Various organic and inorganic compounds both in the gas and particle phase were measured in the emissions of prescribed burnings conducted at two pine-dominated forest areas in Georgia. The measurements of volatile organic compounds (VOCs) and PM2.5 allowed the determination of emission factors for the flaming and smoldering stages of prescribed burnings. The VOC emission factors from smoldering were distinctly higher than those from flaming except for ethene, ethyne, and organic nitrate compounds. VOC emission factors show that emissions of certain aromatic compounds and terpenes such as alpha and beta-pinenes, which are important precursors for secondary organic aerosol (SOA), are much higher from active prescribed burnings than from fireplace wood and laboratory open burning studies. Levoglucosan is the major particulate organic compound (POC) emitted for all these studies, though its emission relative to total organic carbon (mg/g OC) differs significantly. Furthermore, cholesterol, an important fingerprint for meat cooking, was observed only in our in situ study indicating a significant release from the soil and soil organisms during open burning. Source apportionment of ambient primary fine particulate OC measured at two urban receptor locations 20-25 km downwind yields 74 +/- 11% during and immediately after the burns using our new in situ profile. In comparison with the previous source profile from laboratory simulations, however, this OC contribution is on average 27 +/- 5% lower.     

Konferenz der Informationsfreiheitsbeauftragten des Bundes und der Länder

Ohne Zusammenfassung Karsten Neumann, Landesbeauftragter für Datenschutz und Informationsfreiheit Mecklenburg-Vorpommern     

OpenSocial

OpenSocial definiert eine Menge von Programmierschnittstellen für Anwendungen von Drittanbietern im Kontext sozialer Netzwerke. Unter der Verwendung von Standardtechnologien wie HTML und JavaScript k?nnen Entwickler interoperable Anwendungen erstellen, die auf den sozialen Graphen des jeweiligen Netzwerks zugreifen.     

A taxonomy of interaction models for Internet and ATM quality of service architectures

In communication systems there are two worlds at the moment: Internet and ATM. Both possess Quality of Service (QoS) architectures which shall allow them to integrate services of data and telecommunications formerly performed by separate infrastructures. We believe that none of them will be able to oust the other. That means both will exist for at least the middle-term future. Therefore, an interaction between both appears to be necessary, especially in the field of distributed multimedia applications where both worlds meet first. In order to perform gracefully, distributed multimedia applications require a certain QoS provision, in particular from the communication system. Thus, for such applications the existence of heterogeneous IP/ATM networks makes the interaction between Internet and ATM QoS architectures an important issue. In this article a taxonomy of interaction models for the Internet and ATM QoS architectures is developed. We do not let our view be restricted by existing approaches for the interaction between ATM and Internet. Instead we will derive more unconventional models by regarding the possible communication patterns based on different topological variants for heterogeneous IP/ATM networks. The investigation is driven by applications' communication requirements. This is accomplished by examining possibly interacting applications and their communication patterns. The interaction models are contrasted and compared to each other and their assumptions and implications are shown. The derived taxonomy of models allows us to classify proposed approaches for the interaction of Internet and ATM QoS architectures. Thereby we are able to identify the basic assumptions of these approaches and their corresponding restrictions.