89 research outputs found
The Digital Platform Otto.de: A Case Study of Growth, Complexity, and Generativity
We analyze the growth, complexity, and generativity of the digital platform Otto.de, a revelatory case of a large German company that has opened up its internal IT platform to outside developers. We find indication for a superlinear growth pattern fueled by external developers and the introduction of microservices as well as the emergence of a structural separation within the platform. Furthermore, our research shows ways to explain the generativity of a digital platform based on the attention and activity received
Diagnostik der endokrinen Ophthalmopatie mittels Ultrasonographie, Computertomographie und biologischer Bestimmungsmethoden
Vergleichende Untersuchung der endokrinen Ophthalmopathie mittels Ultrasonographie, Computertomographie und Fischbioassay
Bei 35 Patienten mit endokriner Ophthalmopathie (eO) wurde zu den Parametern der Schilddrüsenfunktion (T3, T4, TBI, TRH-Test), dem Szintigramm und der Bestimmung der Schilddrüsenantikörper ergänzend die Ultrasonographie (A-scan) und Computertomographie (CT) der Orbita, sowie der Nachweis exophthalmogener Serumaktivität im Fischbioassay durchgeführt. Charakteristische Sonogramme für eine eO fanden sich in 26 Fällen. Die CT ergab bei 24 von 33 Patienten die Verdickung der musculi recti mediales und/oder der musculi recti laterales, sowie bei 17 Patienten eine Verdichtung im Bereich der Orbitaspitze. Im retrobulbären Bindegewebe zeigte sich nach Kontrastmittelgabe keine signifikante Dichtezunahme. Mit beiden Verfahren zusammen waren nur bei 2 Patienten die Kriterien einer eO nicht erfüllt. Die exophthalmogene Serumaktivität wurde in der IgG-Fraktion im Fischbioassay nachgewiesen; die Trefferquote war mit 69% relativ hoch. Zur Diagnostik der eO kann jedoch der Fischbioassay nicht empfohlen werden
Cathepsin B - indicator for the release of lysosomal cyasteine proteinases in severe trauma and inflammation
Combined X-ray absorption and SEM–EDX spectroscopic analysis for the speciation of thorium in soil
Chemical and spectroscopic investigations on the distribution and enrichment of radionuclides in fuel-cladding interfaces of irradiated high burn-up UOX and MOX fuels
Spectroscopic and chemical investigations on volatile fission and activation products within the fuel-cladding interface of irradiated pressurised water reactor fuel rod segments
Examination of volatile fission and activation products within the fuel-cladding interface of irradiated PWR fuel rod segments
Interlink between solubility, structure, surface and thermodynamics in the ThO(s, hyd)–HO(l) system
The impact of temperature on a freshly precipitated ThO(am, hyd) solid phase was investigated using a combination of undersaturation solubility experiments and a multi-method approach for the characterization of the solid phase. XRD and EXAFS confirm that ageing of ThO(am, hyd) at T = 80°C promotes a significant increase of the particle size and crystallinity. TG-DTA and XPS support that the ageing process is accompanied by an important decrease in the number of hydration waters/hydroxide groups in the original amorphous Th(IV) hydrous oxide. However, while clear differences between the structure of freshly precipitated ThO(am, hyd) and aged samples were observed, the characterization methods used in this work are unable to resolve clear differences between solid phases aged for different time periods or at different pH values. Solubility experiments conducted at T = 22°C with fresh and aged Th(IV) solid phases show a systematic decrease in the solubility of the solid phases aged at T = 80°C. In contrast to the observations gained by solid phase characterization, the ageing time and ageing pH significantly affect the solubility measured at T = 22°C. These observations can be consistently explained considering a solubility control by the outermost surface of the ThO(s, hyd) solid, which cannot be properly probed by any of the techniques considered in this work. Solubility data are used to derive the thermodynamic properties (log ) of the investigated solid phases, and discussed in terms of particle size using the Schindler equation. These results provide new insights on the interlink between solubility, structure, surface and thermodynamics in the ThO(s, hyd)–HO(l) system, with special emphasis on the transformation of the amorphous hydrous/hydroxide solid phases into the thermodynamically stable crystalline oxides
Mineralogical characterization of scalings formed in geothermal sites in the Upper Rhine Graben before and after the application of sulfate inhibitors
Scale formation processes in the surface installations of geothermal power plants may have a negative effect on
power plant performance. In addition, scales formed within the geothermal water circuit frequently accumulate
natural radionuclides. Consequently, scale formation may lead to radiation dose rates, which are of radiological
concern, and deposits, which may have to be disposed as radioactive waste. In order to minimize these problems
and to foster geothermal power plant availability, it is of major interest to understand scale formation processes
and to develop methods for their inhibition. One important pre-requisite towards this goal is a sound mineralogical
and geochemical characterization of the formed material.
Geothermal brines at sites in the Upper Rhine Graben are in general highly mineralized and become, upon
cooling in the heat exchanger, supersaturated with respect to sulfate solid-solutions, e.g. (Ba,Sr)SO4, and other
mineral phases. Some geothermal power plants very successfully tested the application of sulfate scaling inhibitors.
Here we present mineralogical analyses of scale samples from geothermal power plants in the Upper
Rhine Valley deposited in absence and presence of sulfate scaling inhibitors. Solid samples are investigated using
wet-chemistry (after digestion), XRPD, SEM-EDX, XPS, EA-IRMS, Raman spectroscopy, and XANES (for explanation
of abbreviations, see main text).
Samples of scales deposited in the absence of a sulfate scaling inhibitor mainly consist of two phases. The
largest part is made up of a barite type (Ba,Sr,Ca)SO4 solid-solution. Traces of Ra occurring in the scaling are
assumed to be incorporated in the barite type solid solution. Further minor phases are sulfide phases, either an Xray
amorphous nano-particulate phase or galena (PbS).
Since the application of the sulfate inhibitor, sulfate minerals are no longer detectable in the scale samples.
Subsequent scalings are Pb-dominated and consist mainly of galena (PbS), elemental lead (Pb), arsenic (As) and
antimony (Sb). As and Sb are likely present as a nanocrystalline intermetallic mixed compound ((Sb, As) or
Pb3(Sb,As)2S3). The absence of barite-type minerals demonstrates the success of the application of the sulfate
inhibitor. The precipitation of elemental Pb, As, and Sb, which are more noble than iron, may enhance the
corrosion of mild steel pipes in the geothermal water circuit. Elution tests and oxidation of the scalings upon
storage at atmospheric conditions demonstrate that proper disposal of the toxic heavy metal and metalloid
containing scalings may be challenging
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