MORPHODYNAMIC UPSCALING WITH THE MORFAC APPROACH

The Morphological Acceleration Factor (MORFAC) approach for morphodynamic upscaling enables the simulation of long term coastal evolution. However the general validity of the MORFAC concept for coastal applications has not yet been comprehensively investigated. Furthermore, a robust and objective method for the a priori determination of the highest MORFAC that is suitable for a given simulation (i.e. critical MORFAC) does not currently exist. This paper presents some initial results of an ongoing, long-term study that attempts to rigorously and methodically investigate the limitations and strengths of the MORFAC approach. Based on the results of a numerical modelling exercise using the morphodynamic model Delft3D, the main dependencies and sensitivities of the MORFAC approach are investigated. A criterion (based on the CFL condition for bed form migration) for the a priori determination of the critical MORFAC is also proposed.

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Mean PB To Failure - Initial results from a long-term study of disk storage patterns at the RACF

Journal of Physics Conference Series ◽

10.1088/1742-6596/664/4/042057 ◽

2015 ◽

Vol 664 (4) ◽

pp. 042057

Author(s):

C Caramarcu ◽

C Hollowell ◽

T Rao ◽

W Strecker-Kellogg ◽

A Wong ◽

...

Keyword(s):

Term Study ◽

Disk Storage ◽

Long Term Study ◽

Initial Results ◽

Storage Patterns

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A Long-Term Study of Ultraluminous X-ray Sources in NGC 891

Universe ◽

10.3390/universe8010018 ◽

2021 ◽

Vol 8 (1) ◽

pp. 18

Author(s):

Nicholas M. Earley ◽

Vikram V. Dwarkadas ◽

Victoria Cirillo

Keyword(s):

Spiral Galaxy ◽

Spectral Properties ◽

Time Window ◽

Single Model ◽

Term Study ◽

X Ray ◽

Long Term Study ◽

Individual Source

We perform empirical fits to the Chandraand XMM-Newton spectra of three ultraluminous X-ray sources (ULXs) in the edge-on spiral galaxy NGC 891, monitoring the region over a 17-year time window. One of these sources was visible since the early 1990s with ROSAT and was observed multiple times with Chandra and XMM-Newton. Another was visible since 2011. We build upon prior analyses of these sources by analyzing all available data at all epochs. Where possible Chandra data is used, since its superior spatial resolution allows for more effective isolation of the emission from each individual source, thus providing a better determination of their spectral properties. We also identify a new transient ULX, CXOU J022230.1+421937, which faded from view over the course of a two month period from Nov 2016 to Jan 2017. Modeling of each source at every epoch was conducted using six different models ranging from thermal bremsstrahlung to accretion disk models. Unfortunately, but as is common with many ULXs, no single model yielded a much better fit than the others. The two known sources had unabsorbed luminosities that remained fairly consistent over five or more years. Various possibilities for the new transient ULX are explored.

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