scholarly journals Competing feedback in an idealized tide-influenced delta network

2021 ◽  
Author(s):  
Niccolò Ragno ◽  
Nicoletta Tambroni ◽  
Michele Bolla Pittaluga
Keyword(s):  
Equilibrium Configuration ◽  
Flow Conditions ◽  
Tidal Amplitude ◽  
Qualitative Comparison ◽  
River Deltas ◽  
Dual Response ◽  
Reference Parameters ◽  
Upstream Flow ◽  
Morphodynamic Evolution

The morphodynamic evolution of river deltas is intimately tied to flow and sediment partitioning at bifurcations. In this work, we investigate the long-term equilibrium configuration of a simple delta network using an analytical model, which accounts for the effect of small tidal oscillations.Differently from individual bifurcations, where tidal action is always a stabilizing factor, in the case of a tree-like delta with multiple bifurcations a dual response emerges.Specifically, depending on the values of four reference parameters function of tidal amplitude, upstream flow conditions, and on the geometry of the channels, tides can either promote or discourage an unbalanced discharge distribution. This behavior primarily concerns the apex bifurcation, which is affected by the variations of the relative tidal amplitude at the internal nodes. In turn these variations depend on how flow and sediment are diverted upstream. Finally, we discuss the outcomes of the model performing a qualitative comparison with field and experimental tide-influenced deltas. Results highlight the need of including in a unified scheme river-influenced (i.e. depositional) and tide-influenced (i.e. erosional) effects.

scholarly journals Using Long Term Simulations to Understand Heat Transfer Processes during Steady Flow Conditions in Combined Sewers

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 570
Author(s):  
Mohamad Abdel-Aal ◽  
Simon Tait ◽  
Mostafa Mohamed ◽  
Alma Schellart
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Predictive Accuracy ◽  
Flow Conditions ◽  
Empirical Relationships ◽  
Taylor Diagram ◽  
Physical Phenomena ◽  
The Heat Transfer Coefficient ◽  
Empirical Approaches

This paper describes a new heat transfer parameterisation between wastewater and in-sewer air based on understanding the physical phenomena observed in free surface wastewater and in-sewer air. Long-term wastewater and in-sewer air temperature data were collected and studied to indicate the importance of considering the heat exchange with in-sewer air and the relevant seasonal changes. The new parameterisation was based on the physical flow condition variations. Accurate modelling of wastewater temperature in linked combined sewers is needed to assess the feasibility of in-sewer heat recovery. Historically, the heat transfer coefficient between wastewater and in-sewer air has been estimated using simple empirical relationships. The newly developed parameterisation was implemented and validated using independent long-term flow and temperature datasets. Predictive accuracy of wastewater temperatures was investigated using a Taylor diagram, where absolute errors and correlations between modelled and observed values were plotted for different site sizes and seasons. The newly developed coefficient improved wastewater temperature modelling accuracy, compared with the older empirical approaches, which resulted in predicting more potential for heat recovery from large sewer networks. For individual locations, the RMSE between observed and predicted temperatures ranged between 0.15 and 0.5 °C with an overall average of 0.27 °C. Previous studies showed higher RMSE ranges, e.g., between 0.12 and 7.8 °C, with overall averages of 0.35, 0.42 and 2 °C. The new coefficient has also provided stable values at various seasons and minimised the number of required model inputs.

‘When that great ship went down’: Modern maritime disasters and collective memory

2014 ◽  
Vol 26 (4) ◽  
pp. 734-751
Author(s):  
Robert C. Moyer
Keyword(s):  
Collective Memory ◽  
Psychological Impact ◽  
Research Approach ◽  
Short Term ◽  
Qualitative Comparison ◽  
Indirect Measurements ◽  
Internet Media ◽  
The Social ◽  
Air Disaster

The aim of this article is to examine the social and psychological impact of modern maritime disasters upon the population of a technologically developed nation. Through an innovative research approach using various indirect measurements of public interest including the internet, media response, music and film, the article explores the interest displayed by the American public following the loss of ships such as the Titanic, Andrea Doria, Edmund Fitzgerald, and Andrea Gail. In order to provide a basis for qualitative comparison, disasters involving other modes of transportation are also considered, including the Hindenburg crash, the ‘Great Train Wreck of 1918’ in Nashville, TN, the Tenerife air disaster of 1977, and the Concorde crash of 2000. The article seeks to explain why the American public seems to display more short-term and long-term interest in maritime disasters than in disasters involving other forms of transportation.

scholarly journals Long-Term Monitoring of Radiocesium Concentration in Sediments and River Water along Five Rivers in Minami-Soma City during 2012–2016 Following the Fukushima Dai-ichi Nuclear Power Plant Accident

2018 ◽  
Vol 8 (8) ◽  
pp. 1319 ◽  
Author(s):  
Kiyoshi Shizuma ◽  
Wim Ikbal Nursal ◽  
Yushi Sakurai
Keyword(s):  
River Water ◽  
Nuclear Power ◽  
Gamma Ray ◽  
137Cs Concentration ◽  
Flow Conditions ◽  
High Accumulation ◽  
Ge Detector ◽  
Long Term Monitoring ◽  
Term Monitoring

Radiocesium monitoring in sediments and river water has been conducted along five rivers in Minami-Soma City during 2012–2016 to clarify the temporal changes of radiocesium contamination in these rivers. Sampling has been performed annually under normal flow conditions. Sediment and river water samples were collected from four or five sampling sites along each river. Gamma-ray measurements of sediments were performed using a low-background Ge detector and unfiltered river water was utilized to determine radiocesium concentration using a well-type Ge detector. The 137Cs concentration in sediments was highest at upstream sites and slowly decreased to downstream sites for all rivers reflecting the high radioactive contamination in the upstream area. Temporal decrease of the 137Cs concentration was observed in sediments and river water for each river. The effective half-lives were 1.3–2.1 y for sediments, and 0.9–2.1 y for river water from rivers with upstream dams. On the undammed river, the effective half-lives were 4.7 y and 3.7 y for sediment and river water, respectively. Much longer effective-half-lives might reflect the direct transfer of radiocesium from forests and plains to the river. The 137Cs concentration in riverbed was low in downstream areas, however, accumulation of 137Cs over the floodplain was observed. Rapid decrease of 137Cs contamination through rivers will put residents at ease, but high accumulation of radiocesium over floodplains should be noted for future river decontamination.

scholarly journals Effects of Density‐Driven Flows on the Long‐Term Morphodynamic Evolution of Funnel‐Shaped Estuaries

2018 ◽  
Vol 123 (11) ◽  
pp. 2901-2924 ◽  
Author(s):  
Maitane Olabarrieta ◽  
W. Rockwell Geyer ◽  
Giovanni Coco ◽  
Carl T. Friedrichs ◽  
Zhendong Cao
Keyword(s):  
Morphodynamic Evolution ◽  
Effects Of Density

scholarly journals Quantitative and qualitative comparison of three wet aggregate stability methods using a long-term tillage system and crop rotation experiment

2018 ◽  
Vol 98 (4) ◽  
pp. 738-742 ◽  
Author(s):  
L.L. Van Eerd ◽  
A.H. DeBruyn ◽  
L. Ouellette ◽  
D.C. Hooker ◽  
D.E. Robinson
Keyword(s):  
Capital Investment ◽  
Surface Soil ◽  
Aggregate Stability ◽  
Clay Loam Soil ◽  
Qualitative Comparison ◽  
No Till ◽  
Tillage System ◽  
Loam Soil ◽  
Wet Aggregate Stability

Automated wet-sieving is preferred for this clay loam soil due to better sensitivity and savings (time and disposables) despite a larger capital investment. Rotations with greater frequency of winter wheat and no-till compared with conventional plow system had greater wet aggregate stability values, indicating better surface soil quality.

scholarly journals Customer Segmentation Through Path Reconstruction

2020 ◽  
Author(s):  
Santiago García
Keyword(s):  
Rapid Development ◽  
Customer Segmentation ◽  
Smart Phones ◽  
Indoor Environments ◽  
Flow Conditions ◽  
Gps Receivers ◽  
Current State ◽  
Different Types

With the rapid development of smart phones, tablets and their operative systems, many positioning enabled sensors have been built into these devices. Users can now accurately fix their location according to the function of GPS receivers. For indoor environments, as in the case we are studying, WiFi based positioning is preferred to GPS due to the attenuation or obstruction of signals. This paper deals with the automatic classification of customers in a Sports Shop Center on the basis of their movements around the shop's premises. To achieve this goal, we start by collecting (x,y) coordinates from customers while they visit the store. Consequently, any costumer's path through the shop is formed by a list of coordinates, obtained with a frequency of one measurement per minute. Then, a guess about the full trajectory is constructed and a number of parameters about these trajectories is calculated before performing an Unsupervised Learning Clustering Process. As a result, we can identify several types of customers, and the dynamics of their behavior inside the shop. This information is of great value to the company, to be used both in the long term and also in short periods of time, monitoring the current state of the shop at any moment, identifying different types of situation appearing during restricted periods, or predicting customer flow conditions

scholarly journals Synergy between supported ionic liquid-like phases and immobilized palladium N-heterocyclic carbene–phosphine complexes for the Negishi reaction under flow conditions

2020 ◽  
Vol 16 ◽  
pp. 1924-1935
Author(s):  
Edgar Peris ◽  
Raúl Porcar ◽  
María Macia ◽  
Jesús Alcázar ◽  
Eduardo García-Verdugo ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Fine Tuning ◽  
Flow Conditions ◽  
Supported Ionic Liquid ◽  
Phosphine Complexes ◽  
Key Factor ◽  
Catalytic Cycles ◽  
Supported Ionic Liquids ◽  
Catch Mechanism

The combination of supported ionic liquids and immobilized NHC–Pd–RuPhos led to active and more stable systems for the Negishi reaction under continuous flow conditions than those solely based on NHC–Pd–RuPhos. The fine tuning of the NHC–Pd catalyst and the SILLPs is a key factor for the optimization of the release and catch mechanism leading to a catalytic system easily recoverable and reusable for a large number of catalytic cycles enhancing the long-term catalytic performance.

Natural Polymers as Heat and Moisture Exchange Devices for Medical Applications

2014 ◽  
Vol 96 ◽  
pp. 39-44
Author(s):  
Brais Vazquez ◽  
Alessia Nicosia ◽  
Franco Belosi ◽  
Gianni Santachiara ◽  
Paolo Monticelli ◽  
...  
Keyword(s):  
Water Vapour ◽  
Freeze Drying ◽  
Flow Conditions ◽  
Natural Polymers ◽  
Short Term ◽  
Moisture Exchange ◽  
Cyclic Flow ◽  
Porous Matrices ◽  
Heat And Moisture

In recent decades, Heat and Moisture Exchange (HME) devices have been employed increasingly for short-term use in anaesthesia and long-term use in intensive care units. These devices work as heat exchangers, accumulating the patient’s expired heat and moisture and returning them to the patient during the inhalation phase. Porous matrices obtained from freeze-drying of blends of natural polymers exhibit high open and interconnected porosity and water vapour intake characteristics which make them possible candidates for HME devices. Preliminary tests were conducted on specimens made of gelatine blended with chitosan and treated with a non-toxic cross-linking agent. The tests were carried out in cyclic flow conditions with saturated and dried air. Results show water vapour retention comparable with accepted standards for HME devices.

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