scholarly journals Late Holocene flood magnitudes in the Lower Rhine river valley and upper delta resolved by a two‐dimensional hydraulic modelling approach

2021 ◽  
Author(s):  
Bas Meulen ◽  
Anouk Bomers ◽  
Kim M. Cohen ◽  
Hans Middelkoop
Keyword(s):  
Late Holocene ◽  
River Valley ◽  
Two Dimensional ◽  
Rhine River ◽  
Hydraulic Modelling ◽  
Lower Rhine ◽  
Modelling Approach

scholarly journals The Hopewell airburst event, 1699-1567 years ago (252-383 CE)

2021 ◽  
Author(s):  
Kenneth Barnett Tankersley ◽  
Stephen D. Meyers ◽  
Stephanie A. Meyers ◽  
James A. Jordan ◽  
Louis Herzner ◽  
...  
Keyword(s):  
Late Holocene ◽  
River Valley ◽  
Ohio River ◽  
Ohio River Valley ◽  
Catastrophic Event ◽  
Melt Glass

Abstract Meteorites, silicious vesicular melt glass, Fe and Si-rich magnetic spherules, positive Ir and Pt 25 anomalies, and burned charcoal-rich Hopewell habitation surfaces demonstrate that a cosmic airburst event occurred over the Ohio River valley during the late Holocene. A comet-shaped earthwork was constructed near the airburst epicenter. Twenty-nine radiocarbon ages demonstrate that the event occurred between 252 and 383 CE, a time when 69 near-Earth comets were documented. While Hopewell people survived the catastrophic event, it likely contributed to their cultural decline. The Hopewell comet airburst expands our understanding of the frequency and impact of cataclysmic cosmic events on complex human societies.

scholarly journals Two dimensional modelling of the flood zones in the Vistula River Valley in Warsaw

2009 ◽  
Vol 82 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Artur Magnuszewski ◽  
Małgorzata Gutry-Korycka ◽  
Michał Szydłowski
Keyword(s):  
River Valley ◽  
Two Dimensional ◽  
Vistula River

An Investigation of the Predicting Capabilities of a Variable Flow Stress Machining Theory

2001 ◽  
Author(s):  
P. Mathew
Keyword(s):  
Flow Stress ◽  
Material Flow ◽  
Three Dimensional ◽  
Experimental Results ◽  
Two Dimensional ◽  
Variable Flow ◽  
Comparative Results ◽  
Intermittent Cutting ◽  
Theoretical Results ◽  
Modelling Approach

Abstract The Oxley Machining Theory, which has been developed over the last 40 years, is presented in this paper. The capability of the model is described with its initial two-dimensional machining approach followed by the extension to the generalised model for three-dimensional machining. The theoretical results from the model are compared with the experimental results to determine the model capability. A brief description of the work associated with the effect of strain hardening at the interface is presented and comparative results are shown. A further extension of the model to intermittent cutting process of reaming is also presented and a comparison with the experimental results indicates the model developed is quite capable of predicting cutting forces for reaming. In explaining the results obtain, the assumptions made are explained and the inputs required. The limitations of the modelling approach are presented. It is pointed out that the Oxley model is a versatile model as long as proper description of the material flow stress properties is presented.

Modeling debris flow triggered by snow melting in the Barsemdara river valley, Tajikistan

2021 ◽  
Author(s):  
Viktoriia Kurovskaia ◽  
Sergey Chernomorets ◽  
Tatyana Vinogradova ◽  
Inna Krylenko
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Human Life ◽  
River Valley ◽  
Viscoplastic Fluid ◽  
Two Dimensional ◽  
Residential Areas ◽  
Subsequent Formation ◽  
Hazard Level ◽  
Output Information

<p>Debris flow is one of the most hazardous events that occur in all mountain regions.  Direct debris flow damage includes loss of human life, destruction of houses and facilities, damage to roads, rail lines and pipelines, vehicle accidents, and many other losses that are difficult to quantify. In July 2015, in the valley of the Barsemdara River (Gorno-Badakhshan Autonomous Region, Tajikistan), plenty of debris flows were observed. As a result, residential areas, social facilities, and infrastructure in Barsem village and neighboring settlements were destroyed and flooded. Besides, debris flow deposits blocked the Gunt River with the subsequent formation of a dammed lake with a maximum volume of 4.0 million m<sup>3</sup>. <br>The aim of this study was to obtain hydrographs of debris flow waves in the source and detailed zoning of the Barsemdara river valley. For the debris flow source, we applied transport-shift model. Equations of this model were developed by Yu.B. Vinogradov basing on Chemolgan experiments of artificial debris flows descending. Previously, the model characteristics were compared with the observational data of the Chemolgan experiments, and the results were found to be satisfactory [Vinogradova, Vinogradov, 2017]. Based on the equations, a computer program was created in the programming language Python. Besides, we improved the model by adding flow velocity calculations, and eventually it became possible to obtain hydrographs. To investigate quantitative characteristics of the debris flow in the river valley we implied a two-dimensional (2D) model called FLO-2D PRO. It is based on the numerical methods for solving the system of Saint-Venant equations. Besides, in this model, it is assumed that debris flows move like a Bingham fluid (viscoplastic fluid) [O'Brien et al., 1993]. The input information for modeling was digital elevation model (DEM) and previously obtained hydrographs. The output information included flow depth, velocity distribution and hazard level of the territory. The results of the study will be reported.</p><p>1.    Vinogradova T.A., Vinogradov A.Y. The Experimental Debris Flows in the Chemolgan River Basin // Natural Hazards. – 2017. – V. 88. – P. 189-198.<br>2.    O'Brien J. S., Julien P.Y., Fullerton W.T. Two-dimensional water flood and mudflow simulation //Journal of hydraulic engineering. – 1993. – V. 119, No 2. – P. 244-261.</p>

Repeated detection of polystyrene microbeads in the Lower Rhine River

2019 ◽  
Vol 245 ◽  
pp. 634-641 ◽  
Author(s):  
Thomas Mani ◽  
Pascal Blarer ◽  
Florian R. Storck ◽  
Marco Pittroff ◽  
Theo Wernicke ◽  
...  
Keyword(s):  
Rhine River ◽  
Lower Rhine
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