Entity linking systems for literature reviews

Scientometrics - Computer-assisted methods and tools can help researchers automate the coding process of literature reviews and accelerate the literature review process. However, existing...     

Undercooling and demixing of copper-based alloys

Since the beginning of materials science research under microgravity conditions immiscible alloys have been an interesting subject. New possibilities to investigate such systems are offered by containerless processing techniques. Of particular interest is the ternary system Cu-Fe-Co, and its limiting binaries, Cu-Co and Cu-Fe. They all show a metastable miscibility gap in the regime of the undercooled melt. Within the ESA-MAP project “CoolCop”, different aspects of this alloy have been investigated; results obtained so far are reported here.     

Ammoniaksynthese als Beispiel einer stofflichen Nutzung von intermittierend erzeugtem Wasserstoff

Producing hydrogen‐rich chemicals, such as methane, ammonia or methanol, from renewable energy may foster the integration of renewables into the current energy system. Here, a flexible ammonia synthesis concept is introduced, which is then compared to the widely discussed power‐to‐gas concepts on a technical and economic level. The current ammonia prices result in comparably high hydrogen‐specific revenues, which imply the ability to operate the system more profitable under fluctuating electricity prices and thereby increase the plant capacity factor.     

The effect of modern thermal neutron scattering sublibraries on criticality safety evaluations of wet storage pools

Within the framework of a recent criticality safety evaluation (CSE) performed for the licensing of a new commercial wet storage pool using MCNPX-2.5.0 along with the ENDF/B-VII.0 and JEFF-3.1 continuous energy cross-section libraries, the maximum permissible initial fuel-enrichment limit for water reflected configurations was found to be dependant upon the applied neutron cross section library. More detailed investigations showed that the difference is mainly caused by different sublibraries for thermal neutron scattering based on parameterizations of the S(α, β) scattering matrix. This paper addresses the main findings of these investigations and emphasizes which configurations are particularly sensitive to the parameterization of S(α, β) applied in the CSE analysis. The results are presented in an attempt, on the one hand, to assess more precisely the sensitivity upon thermal scattering modeling data in CSE of wet storage pools, and on the other hand, to assess whether the data employed in the most recent neutron data libraries can be considered as an improvement for this type of analyses.     

Microstructure and Compression Strength of Novel TRIP‐Steel/Mg‐PSZ Composites

Novel composites on basis of austenitic stainless TRIP‐steel as matrix with reinforcements of Mg‐PSZ are presented. Compact rods were produced by cold isostatic pressing and sintering, square honeycomb samples by the ceramic extrusion technique. The samples are characterized by optical and scanning electron microscopy before and after deformation, showing the microstructure and the deformation‐ induced martensite formation. The mechanical properties of samples with 5 vol% zirconia are superior compared to zirconia‐free samples and composites with higher zirconia contents in terms of bending and compression tests. The honeycomb samples exhibit extraordinary high specific energy absorption in compression.     

Elektromagnetisches Geräusch umrichtergespeister permanenterregter synchronmaschinen

Übersicht Es wird ein Verfahren zur Berechnung der elektromagnetischen Schwingungsanregung von permanenterregten Synchronmaschinen mit beliebiger Strangzahl angegeben, das es gestattet, den zeitlichen Verlauf der Ströme in den einzelnen Wicklungssträngen zu berücksichtigen, der häufig weder periodisch noch phasensymmetrisch ist. Hierzu wird der räumliche und zeitliche Verlauf des Luftspaltfeldes und des Strombelages diskretisiert. Aus diesen Größen erhält man die radialen und tangentialen Kräfte. Anschließende räumliche und zeitliche Fourieranalysen ergeben die Radial- und Tangentialkraftwellen sowie die Pendelmomente als Ausgangspunkt für die Schwingungsberechnung. Die Einflüsse einer Dämpferwicklung, der Ständernutung und der Schrägung werden berücksichtigt.

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Electromagnetic acoustic noise of converter-fed permanent-field synchronous motorsPart 1: Theoretical treatise

Contents A method is given for calculating the electromagnetic excitation of vibrations ofm-phase permanentfield synchronous machines. It takes into account the wave-form of currents in the individual phase windings which are often neither periodic nor phase balanced. For that purpose the spatial distribution and also the temporal course of the airgap field and of the linear current density are discretised in order to get the radial and tangential forces. Spatial and temporal Fourier analyses yield the waves of radial and tangential forces and also the pulsating torques. They are used to calculate the vibrations. The influences of a damper winding, of the stator slotting and of the skewing are considered.

     

Application of GaN-based ultraviolet-C light emitting diodes--UV LEDs--for water disinfection

GaN-based ultraviolet-C (UV-C) light emitting diodes (LEDs) are of great interest for water disinfection. They offer significant advantages compared to conventional mercury lamps due to their compact form factor, low power requirements, high efficiency, non-toxicity, and overall robustness. However, despite the significant progress in the performance of semiconductor based UV LEDs that has been achieved in recent years, these devices still suffer from low emission power and relatively short lifetimes. Even the best UV LEDs exhibit external quantum efficiencies of only 1-2%.The objective of this study was to investigate the suitability of GaN-based UV LEDs for water disinfection. The investigation included the evaluation of the performance characteristics of UV LEDs at different operating conditions as well as the design of a UV LED module in view of the requirements for water treatment applications. Bioanalytical testing was conducted using Bacillus subtilis spores as test organism and UV LED modules with emission wavelengths of 269 nm and 282 nm.The results demonstrate the functionality of the developed UV LED disinfection modules. GaN-based UV LEDs effectively inactivated B. subtilis spores during static and flow-through tests applying varying water qualities. The 269 nm LEDs reached a higher level of inactivation than the 282 nm LEDs for the same applied fluence. The lower inactivation achieved by the 282 nm LEDs was compensated by their higher photon flux. First flow-through tests indicate a linear correlation between inactivation and fluence, demonstrating a well designed flow-through reactor. With improved light output and reduced costs, GaN-based UV LEDs can provide a promising alternative for decentralised and mobile water disinfection systems.