scholarly journals AUTOMATIC INCORPORATION OF CIRCULAR RIVERBANK FAILURES IN TWO-DIMENSIONAL FLOOD MODELING

2020 ◽  
Author(s):  
Ismail Ouchebri ◽  
Tew-Fik Mahdi
Keyword(s):  
Morphological Changes ◽  
Limit Equilibrium ◽  
Mobile Bed ◽  
Novel Approach ◽  
River Hydraulics ◽  
Sediment Redistribution ◽  
Alluvial Channel ◽  
Coupling Procedure ◽  
Morphodynamic Modeling ◽  
Continuous Dynamic

Riverbanks undergo changes caused by river hydraulics and by the possible landslides that change the channel bank profiles. Those failures are an important form of alluvial channel adjustments but are usually difficult to include during morphodynamic modeling. This paper proposes a novel approach combining a 2D depth-averaged hydrodynamic, sediment transport and mobile-bed model, a limit equilibrium slope-stability model, and a bank failure sediment redistribution submodule, into a fully automatic and continuous dynamic simulation to predict morphological changes for a river reach undergoing exceptional flooding. All mesh nodes located within the mass wasting zone will be automatically updated, allowing a new bank face form. The failed materials is redistributed in the transect according to the geometry of the landslides observed at the study site. The Outaouais River at Notre-Dame-Du Nord, Quebec, is used to test the coupling procedure. Typical results showing the effectiveness of the developed framework are presented and discussed.

scholarly journals Riverine Sediment Changes and Channel Pattern of a Gravel-Bed Mountain Torrent

2020 ◽  
Vol 12 (18) ◽  
pp. 3065 ◽  
Author(s):  
Gernot Seier ◽  
Stefan Schöttl ◽  
Andreas Kellerer-Pirklbauer ◽  
Raphael Glück ◽  
Gerhard K. Lieb ◽  
...  
Keyword(s):  
High Resolution ◽  
Sediment Yield ◽  
Subsurface Water ◽  
Braided River ◽  
River Channels ◽  
Entire Study ◽  
Near Surface ◽  
Highly Active ◽  
Sediment Redistribution ◽  
Alluvial Channel

The alluvial channel of the Langgriesgraben (Austria) is a highly active geomorphic riverine subcatchment of the Johnsbach River with intermittent discharge and braided river structures. The high sediment yield entails both issues and opportunities. For decades, the riverbed was exploited as a gravel pit. Today, as part of the Gesäuse National Park and after renaturation, the sediment yield endangers a locally important bridge located at the outlet of the subcatchment. High-resolution geospatial investigations are vital for the quantification of sediment redistribution, which is relevant in terms of river management. Based on unmanned aerial system (UAS) surveys in 2015 (July, September, and October) and 2019 (August and October), high-resolution digital elevation models (DEMs) were generated, which enable us to quantify intra- and multiannual sediment changes. As surface runoff at the subcatchment occurs on only a few days per year with flash floods and debris flows that are not predictable and thus hardly observable, the subsurface water conditions were assessed based on electrical resistivity tomography (ERT) measurements, which were conducted in 2019 (November) and 2020 (May, June). Results of the UAS-based surveys showed that, considering the data quality, intra-annual sediment changes affected only small subareas, whereas multiannual changes occurred in the entire study area and amount to net sediment deposition of ≈0.3–0.4 m3m−2, depending on the channel section. In addition, the elevation differences for both intra-annual surveys revealed linear patterns that can be interpreted as braided river channels. As in both survey periods the same areas were affected by changes, it can be concluded that the channel mainly affected by reshaping persisted within the 4-year observation period. The subsurface investigations showed that although both near-surface and groundwater conditions changed, near-surface sediments are mostly dry with a thickness of several meters during the observations.

scholarly journals Coastal morphological changes in the Red River Delta under increasing natural and anthropic stresses

2019 ◽  
Vol 2 (1) ◽  
pp. 51-71 ◽  
Author(s):  
Daidu Fan ◽  
Dac Ve Nguyen ◽  
Jianfeng Su ◽  
Vuong Van Bui ◽  
Dinh Lan Tran
Keyword(s):  
Coastal Erosion ◽  
Land Reclamation ◽  
Morphological Changes ◽  
River Delta ◽  
Sediment Supply ◽  
Red River ◽  
Coastal Protection ◽  
Mangrove Forests ◽  
Red River Delta ◽  
Sediment Redistribution

River deltas are the best place to study intense human–earth interactions and the resultant morphological changes and sedimentary records. The coastal evolution history of the Red River Delta (RRD) is examined by time-series analysis of multiple coastline locations. We find that spatiotemporal variation in seawall locations and vegetation lines are obviously site-specific due to intense human interference, while changes in 0 m isobaths are highly dependent on external stresses. Coastal erosion and deposition patterns are determined firstly by sediment inputs from different distributaries, and secondly by sediment redistribution with tides, waves, and longshore currents. The causes of chronic erosion along the Hai Hau coast include swift distributary channels, negligible sediment supply by the regional longshore current, and continuous sediment export by local wave-generated longshore and offshore currents. The area of intertidal flats decreased significantly due to land reclamation and decelerating coastal accretion. The area of mangrove forests decreased first due to human deforestation, and then increased gradually due to artificial plantation. Poorly designed coastal infrastructures may increase risks of coastal erosion and flooding disasters. More coastal sectors in the RRD may turn into erosion due to continuous decrease in riverine sediment discharges, deserving more attention on proper coastal protection and management.

scholarly journals Coastal Modelling Environment version 1.0: a framework for integrating landform-specific component models in order to simulate decadal to centennial morphological changes on complex coasts

2017 ◽  
Vol 10 (7) ◽  
pp. 2715-2740 ◽  
Author(s):  
Andrés Payo ◽  
David Favis-Mortlock ◽  
Mark Dickson ◽  
Jim W. Hall ◽  
Martin D. Hurst ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Simulation Models ◽  
Coastal Structures ◽  
Coastal Morphology ◽  
Novel Approach ◽  
Coastal Modelling ◽  
Coupling Approach ◽  
Modelling Environment ◽  
Alongshore Sediment Transport ◽  
Component Models

Abstract. The ability to model morphological changes on complex, multi-landform coasts over decadal to centennial timescales is essential for sustainable coastal management worldwide. One approach involves coupling of landform-specific simulation models (e.g. cliffs, beaches, dunes and estuaries) that have been independently developed. An alternative, novel approach explored in this paper is to capture the essential characteristics of the landform-specific models using a common spatial representation within an appropriate software framework. This avoid the problems that result from the model-coupling approach due to between-model differences in the conceptualizations of geometries, volumes and locations of sediment. In the proposed framework, the Coastal Modelling Environment (CoastalME), change in coastal morphology is represented by means of dynamically linked raster and geometrical objects. A grid of raster cells provides the data structure for representing quasi-3-D spatial heterogeneity and sediment conservation. Other geometrical objects (lines, areas and volumes) that are consistent with, and derived from, the raster structure represent a library of coastal elements (e.g. shoreline, beach profiles and estuary volumes) as required by different landform-specific models. As a proof-of-concept, we illustrate the capabilities of an initial version of CoastalME by integrating a cliff–beach model and two wave propagation approaches. We verify that CoastalME can reproduce behaviours of the component landform-specific models. Additionally, the integration of these component models within the CoastalME framework reveals behaviours that emerge from the interaction of landforms, which have not previously been captured, such as the influence of the regional bathymetry on the local alongshore sediment-transport gradient and the effect on coastal change on an undefended coastal segment and on sediment bypassing of coastal structures.

scholarly journals Effect of Methionine Diet on Metabolic and Histopathological Changes of Rat Hippocampus

2019 ◽  
Vol 20 (24) ◽  
pp. 6234 ◽  
Author(s):  
Maria Kovalska ◽  
Petra Hnilicova ◽  
Dagmar Kalenska ◽  
Barbara Tothova ◽  
Marian Adamkov ◽  
...  
Keyword(s):  
Metabolic Profile ◽  
Morphological Changes ◽  
Brain Area ◽  
Hippocampal Volume ◽  
Cerebrovascular Diseases ◽  
Resonance Spectroscopy ◽  
1H Mrs ◽  
Morphological Pattern ◽  
Novel Approach ◽  
Male Wistar Rats

Hyperhomocysteinemia (hHcy) is regarded as an independent and strong risk factor for cerebrovascular diseases, stroke, and dementias. The hippocampus has a crucial role in spatial navigation and memory processes and is being constantly studied for neurodegenerative disorders. We used a moderate methionine (Met) diet at a dose of 2 g/kg of animal weight/day in duration of four weeks to induce mild hHcy in adult male Wistar rats. A novel approach has been used to explore the hippocampal metabolic changes using proton magnetic resonance spectroscopy (1H MRS), involving a 7T MR scanner in combination with histochemical and immunofluorescence analysis. We found alterations in the metabolic profile, as well as remarkable histo-morphological changes such as an increase of hippocampal volume, alterations in number and morphology of astrocytes, neurons, and their processes in the selective vulnerable brain area of animals treated with a Met-enriched diet. Results of both methodologies suggest that the mild hHcy induced by Met-enriched diet alters volume, histo-morphological pattern, and metabolic profile of hippocampal brain area, which might eventually endorse the neurodegenerative processes.

scholarly journals Sea Level at the Coast from Video-Sensed Waves: Comparison to Tidal Gauges and Satellite Altimetry

2019 ◽  
Vol 36 (8) ◽  
pp. 1591-1603 ◽  
Author(s):  
G. Abessolo Ondoa ◽  
R. Almar ◽  
B. Castelle ◽  
L. Testut ◽  
F. Léger ◽  
...  
Keyword(s):  
Sea Level ◽  
Morphological Changes ◽  
Tide Gauge ◽  
Accurate Determination ◽  
Acoustic Doppler Current Profiler ◽  
Video Camera ◽  
Water Levels ◽  
Inversion Method ◽  
Sea Levels ◽  
Novel Approach

AbstractNearshore complex and energetic hydrodynamic conditions make observing evolving processes during extreme and short-term events difficult. In particular, total sea levels at the coast are hard to measure with current techniques. Sea level is commonly measured with tidal gauges and spaceborne altimetry, which lack essential details of spatial and wave-related sea level variability along the coast. Hence, novel techniques, adapted to nearshore areas, are required. This paper presents the first-time use of video cameras to derive the total sea level at the coast. This novel approach consists of estimating time-varying total water levels by applying a celerity-based depth inversion method, which is conventionally used to estimate bathymetry from video. The video-derived total sea levels are compared to sea levels derived from an in situ acoustic Doppler current profiler (ADCP), the nearest tide gauge, and altimetry. A tidal harmonic analysis is performed on the video-derived water levels, yielding an accurate determination of the dominant tidal harmonics. However, it remains difficult to separate bathymetric changes due to the waves on beaches when rapid morphological changes occur under energetic conditions. Nonetheless, video-derived water-level anomalies are in good agreement with state-of-the-art altimetry products. Although there is still work to be done, the results show the potential to measure total sea level at the coast using video camera systems.

scholarly journals Analysis of morphological changes after facial massage by a novel approach using three-dimensional computed tomography

2016 ◽  
Vol 23 (3) ◽  
pp. 369-375 ◽  
Author(s):  
H. Nishimura ◽  
I. Okuda ◽  
N. Kunizawa ◽  
T. Inoue ◽  
Y. Nakajima ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Morphological Changes ◽  
Three Dimensional ◽  
Novel Approach

scholarly journals Relative role of sediment entrainments on log-law parameters of longitudinal velocity distributions in mobile bed flows

2021 ◽  
Vol 69 (3) ◽  
pp. 243-254
Author(s):  
Pritam Malakar ◽  
Ratul Das
Keyword(s):  
Current Knowledge ◽  
Reynolds Shear Stress ◽  
Longitudinal Velocity ◽  
Flow Characteristics ◽  
Relative Role ◽  
Mobile Bed ◽  
Alluvial Channel ◽  
Bed Slope ◽  
Additional Support ◽  
Cohesive Bed

Abstract In alluvial channel, the non-cohesive bed particles are frequently accelerated by the flows and there has been an inconclusive debate on the deviations of logarithmic law parameters that demonstrate the velocity distributions in flows. Present study aims to elucidate the current knowledge of overwhelming theoretical and experimental evidences in this regard within the scope of near-bed turbulent flow characteristics. The study was conducted in two folds collecting instantaneous velocity of flow over a rigid sand bed under clear water flow conditions and compared to those over mobile sand beds under equilibrium bed-load. Results corroborated additional support to confirm the upward shifting of zero-velocity level in mobile bed flows. Most importantly, the conventional value of von Kármán coefficient significantly deviates in mobile bed flows compared to those in rigid sand bed. Also, the frictional velocity obtained from the bed slope consistently differs to those obtained from the Reynolds shear stress (RSS) distributions owing to transfer of stress aliquot to the bed particles. The mechanism is well demonstrated with the energy-momentum transfer within the framework of energy budget concept which shows near-bed negative pressure energy diffusion rates with increasing turbulence production in mobile bed flows.

scholarly journals Use of scanning area related multiple degradation profiles for AFM assessment of polystyrene/PC61BM nanocomposite surface deterioration

2018 ◽  
Vol 36 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Andrzej Sikora ◽  
Magdalena Moczała ◽  
Bartosz Boharewicz
Keyword(s):  
Uv Radiation ◽  
Morphological Changes ◽  
Spatial Inhomogeneity ◽  
Novel Approach ◽  
Scanning Area ◽  
Mass Proportion ◽  
Measurement Methodology ◽  
The Media

AbstractIn this paper, we present a novel approach developed in order to increase the reliability and accuracy of AFM investigation of morphological changes in a nanocomposite due to exposure to the media causing its degradation. By precise sample positioning and repetitive determination of the roughness changes at specific spots, we were able to create space-related degradation profiles. As the multi-step experiment based on exposure/scanning cycle was performed, we were able to observe a unique response of investigated samples revealing spatial inhomogeneity of the material. In order to present the measurement methodology, we used polystyrene samples containing various quantities of PC61BM nanofiller (0 %, 5 %, 10 % and 20 % of mass proportion), which was exposed to 370 nm UV radiation. Obtained data can be recognized as specific fingerprints of investigated materials. The solution based on creation and analysis of degradation profiles can be particularly useful for diagnostics of nanomaterials and nanocomposites to test their resistance to various conditions.

scholarly journals Identification of conserved transcriptome features between humans and Drosophila in the aging brain utilizing machine learning on combined data from the NIH Sequence Read Archive

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255085
Author(s):  
Joe L. Webb ◽  
Simon M. Moe ◽  
Andrew K. Bolstad ◽  
Elizabeth M. McNeill
Keyword(s):  
Morphological Changes ◽  
Age Groups ◽  
Model Organisms ◽  
Aging Brain ◽  
Sequencing Data ◽  
Genetic Changes ◽  
Age Related ◽  
Novel Approach ◽  
Increased Risk ◽  
The Brain

Aging is universal, yet characterizing the molecular changes that occur in aging which lead to an increased risk for neurological disease remains a challenging problem. Aging affects the prefrontal cortex (PFC), which governs executive function, learning, and memory. Previous sequencing studies have demonstrated that aging alters gene expression in the PFC, however the extent to which these changes are conserved across species and are meaningful in neurodegeneration is unknown. Identifying conserved, age-related genetic and morphological changes in the brain allows application of the wealth of tools available to study underlying mechanisms in model organisms such as Drosophila melanogaster. RNA sequencing data from human PFC and fly heads were analyzed to determine conserved transcriptome signatures of age. Our analysis revealed that expression of 50 conserved genes can accurately determine age in Drosophila (R2 = 0.85) and humans (R2 = 0.46). These transcriptome signatures were also able to classify Drosophila into three age groups with a mean accuracy of 88% and classify human samples with a mean accuracy of 69%. Overall, this work identifies 50 highly conserved aging-associated genetic changes in the brain that can be further studied in model organisms and demonstrates a novel approach to uncovering genetic changes conserved across species from multi-study public databases.

scholarly journals Morphological Features Extracted by AI Associated with Spatial Transcriptomics in Prostate Cancer

Cancers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 4837
Author(s):  
Eduard Chelebian ◽  
Christophe Avenel ◽  
Kimmo Kartasalo ◽  
Maja Marklund ◽  
Anna Tanoglidi ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dimensionality Reduction ◽  
Morphological Changes ◽  
Morphological Features ◽  
Cancer Type ◽  
Spatially Resolved ◽  
Morphological Heterogeneity ◽  
Novel Approach ◽  
Genetic Profiles ◽  
Molecular Patterns

Prostate cancer is a common cancer type in men, yet some of its traits are still under-explored. One reason for this is high molecular and morphological heterogeneity. The purpose of this study was to develop a method to gain new insights into the connection between morphological changes and underlying molecular patterns. We used artificial intelligence (AI) to analyze the morphology of seven hematoxylin and eosin (H&E)-stained prostatectomy slides from a patient with multi-focal prostate cancer. We also paired the slides with spatially resolved expression for thousands of genes obtained by a novel spatial transcriptomics (ST) technique. As both spaces are highly dimensional, we focused on dimensionality reduction before seeking associations between them. Consequently, we extracted morphological features from H&E images using an ensemble of pre-trained convolutional neural networks and proposed a workflow for dimensionality reduction. To summarize the ST data into genetic profiles, we used a previously proposed factor analysis. We found that the regions were automatically defined, outlined by unsupervised clustering, associated with independent manual annotations, in some cases, finding further relevant subdivisions. The morphological patterns were also correlated with molecular profiles and could predict the spatial variation of individual genes. This novel approach enables flexible unsupervised studies relating morphological and genetic heterogeneity using AI to be carried out.

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