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The formation of single-channel and multiple-channel rivers on large slopes

Misiura K., Czechowski L., Witek P., Bendiukova A.

Geological Quarterly

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2016

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Vol. 60, No. 4

981--989

EN

We investigated the formation of different types of rivers depending on slope, total discharge, and grain size. Calculations were performed using numerical package CCHE2D, developed by the National Center for Computational Hydroscience and Engineering. The model is based on the Navier-Stokes equations for depth-integrated two-dimensional turbulent flow and the three-dimensional convection-diffusion equation of sediment transport. For each model we use the same river geometry, suspended load concentration, and bedload transport rate. We distinguish three types of rivers using two methods for classification (single-channel, multiple-channels and transitional). We found that the trend line for transitional rivers is an increasing function of Q in space (Q, d) and that for large S the number of multichannel rivers decreases.

2

Modelling of small river deltas : the dependence of morphology on grain size and discharge

Witek P., Czechowski L., Misiura K.

Geological Quarterly

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2016

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Vol. 60, No. 4

975--980

EN

We studied the dependence of the morphology of small river deltas on the grain size, the total discharge, and the slope of the deposits. We use Computational Fluid Dynamics (CFD) methods of numerical modelling. For all models we used the same initial geometry of the river valley and a portion of the lake. Our simulations show the expected dependence of the shape of our simulated small deltas on the grain size. Moreover, we find that the final type of delta could be characterized by the average slope in the region close to the delta front.

3

Numerical modelling of rivers on Earth and Titan

Misiura K., Czechowski L.

Geological Quarterly

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2015

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Vol. 59, No. 3

565--580

EN

The differences in the evolution of rivers on Earth and on Titan are investigated. Dynamical analysis of the rivers was performed using a numerical package CCHE2D developed by the National Center for Computational Hydroscience and Engineering, University of Mississippi. The model is based on the Navier-Stokes equations for depth-integrated two-dimensional turbulent flow and the three-dimensional convection-diffusion equation of sediment transport. The model enables investigation of the evolution of rivers as a function of total discharge and other parameters of the river. Series of short (from one to several hours) and long (up to 67 days) simulations were performed. We have found that three different liquid hydrocarbons considered for Titan’s rivers give similar velocity fields. It was also found that the suspended load is the main means of transport in Titan’s rivers, while in terrestrial ones, for the same discharge, the bedload could be of the same order as suspended load. Moreover, we suppose that for specific boundary conditions, the evolution of rivers on the Earth promotes the development of braided rivers, while for the same conditions evolution on Titan favours regular meandering rivers

4

Determination of Enantiomeric Excess of Cyclophosphamide by X-Ray Powder Diffraction (XRPD)

Tadeusiak E., Kruszyński R., Misiura K.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 3

431-435

EN

The anticancer agent: cyclophosphamide 1 was studied by X-ray powder diffraction. The linear correlations between intensity/spectra from X-ray powder diffraction/and enantiomeric excess was observed.