scholarly journals CASE STUDIES OF DELAWARE'S TIDAL INLETS: ROOSEVELT AND INDIAN RIVER INLETS

1978 ◽  
Vol 1 (16) ◽  
pp. 75
Author(s):  
W.A. Dennis ◽  
G.A. Lanan ◽  
R.A. Dalrymple
Keyword(s):  
Field Measurements ◽  
Sediment Traps ◽  
Substantial Effect ◽  
Tidal Inlets ◽  
One Dimensional ◽  
Major Mechanism ◽  
The Past ◽  
Depositional Patterns ◽  
Indian River ◽  
Flow Through

Studies were undertaken to document the past and present characteristics and trends of Delaware's two major tidal inlets, Roosevelt and Indian River Inlets. It was found that both inlet complexes are effective sediment traps causing considerable downdrift erosion. The major mechanism by which sand enters Indian River Inlet is by overtopping the impounded south jetty. At Roosevelt Inlet sediments are readily transported past the severed steel sheet pile jetties. The results of a one-dimensional hydraulic model, as well as field measurements, predict the presence of a mean southerly flow through the canal and bay system which connects these two inlets. This flow is shown to have a substantial effect on the behavior and stability of these entranceways, causing major asymmetries on the depositional patterns at each location. Roosevelt Inlet was found to have a strong tendency to trap sediment within its throat; whereas, Indian River Inlet, on the opposite end of the system, was found to retain large quantities of sand on its developing ebb tidal shoal.

scholarly journals Morphology of Tigris River within Baghdad City

2012 ◽  
Vol 9 (5) ◽  
pp. 5671-5695
Author(s):  
A. A. Ali ◽  
N. A. Al-Ansari ◽  
S. Knutsson
Keyword(s):  
Cross Sections ◽  
Field Measurements ◽  
Water Levels ◽  
Huge Amount ◽  
One Dimensional ◽  
The Past ◽  
Tigris River ◽  
Critical Discharge ◽  
Diyala River ◽  
Flood Waves

Abstract. Changes in the morphology of the River Tigris within Baghdad City are very noticeable in recent years. The number of islands is increasing with time despite the fact that huge amount of sediments are trapped in reservoirs upstream Baghdad City. The debris of destroyed bridges in the wars of 1991 and 2003 had enhanced the development of these islands. As a consequence the ability of the river had been reduced to pass flood waves. This fact caused partial flooding of parts of Baghdad City. Cross sections of the River Tigris were surveyed in three occasions (1976, 1991 and 2008). The last survey conducted in 2008 by Ministry of Water Resources covered 49 km of the river from Al-Muthana Bridge to its confluence with Diyala River at 250 m intervals. The data was used to predict the maximum flood capacity for the river using one-dimensional hydraulic model for steady flow "HEC-RAS". Calibration was carried out for the model using field measurements for water levels along the last 15 km from its reach and the last 10 yr observations at Sarai Baghdad station. The average discharge of the river in Baghdad had been calculated for the past ten years. This value was introduced in the model. Then different scenarios were applied by increasing the discharge in order to find out the critical discharge that can cause inundation. The procedure continued to detect the areas that had been inundated and the water level was recorded. The model showed a significant reduction in the current river capacity in comparison with what the river had used to hold during floods of 1971 and 1988. The three surveys conducted on the same reach of the River Tigris indicated that the capacity of the river to pass water had been decreased. In addition the changes in the morphology of the river cross sections were very clear.

Managing rivers for conservation and ecotourism in the Kruger National Park

1995 ◽  
Vol 32 (5-6) ◽  
pp. 227-233 ◽  
Author(s):  
F. J. Venter ◽  
A. R. Deacon
Keyword(s):  
National Park ◽  
Good Condition ◽  
Kruger National Park ◽  
Rapid Expansion ◽  
Natural Environments ◽  
The West ◽  
The Past ◽  
Management Actions ◽  
Flow Through ◽  
Three Rivers

Six major rivers flow through the Kruger National Park (KNP). All these rivers originate outside and to the west of the KNP and are highly utilized. They are crucially important for the conservation of the unique natural environments of the KNP. The human population growth in the Lowveld during the past two decades brought with it the rapid expansion of irrigation farming, exotic afforestation and land grazed by domestic stock, as well as the establishment of large towns, mines, dams and industries. Along with these developments came overgrazing, erosion, over-utilization and pollution of rivers, as well as clearing of indigenous forests from large areas outside the borders of the KNP. Over-utilization of the rivers which ultimately flow through the KNP poses one of the most serious challenges to the KNP's management. This paper gives the background to the development in the catchments and highlights the problems which these have caused for the KNP. Management actions which have been taken as well as their results are discussed and solutions to certain problems proposed. Three rivers, namely the Letaba, Olifants and Sabie are respectively described as examples of an over-utilized river, a polluted river and a river which is still in a fairly good condition.

Certain Problems with the Application of Stochastic Diffusion Processes for the Description of Chemical Engineering Phenomena. Stochastic Model of Non-Isothermal Flow Chemical Reactor

1996 ◽  
Vol 61 (2) ◽  
pp. 242-258 ◽  
Author(s):  
Vladimír Kudrna ◽  
Libor Vejmola ◽  
Pavel Hasal
Keyword(s):  
Stochastic Model ◽  
Chemical Engineering ◽  
Diffusion Processes ◽  
Dispersion Model ◽  
Chemical Reactor ◽  
Segregation Index ◽  
One Dimensional ◽  
A Value ◽  
Isothermal Case ◽  
Flow Through

Recently developed stochastic model of a one-dimensional flow-through chemical reactor is extended in this paper also to the non-isothermal case. The model enables the evaluation of concentration and temperature profiles along the reactor. The results are compared with the commonly used one-dimensional dispersion model with Danckwerts' boundary conditions. The stochastic model also enables to evaluate a value of the segregation index.

Evaluation methods of the daylight performance and potential energy saving of tubular daylight guide systems: A review

2021 ◽  
pp. 1420326X2199241
Author(s):  
Hanlin Li ◽  
Dan Wu ◽  
Yanping Yuan ◽  
Lijun Zuo
Keyword(s):  
Potential Energy ◽  
Energy Saving ◽  
Energy Savings ◽  
Performance Metrics ◽  
Field Measurements ◽  
Building Design ◽  
Estimation Methods ◽  
The Past ◽  
Potential Energy Saving ◽  
Daylight Performance

In the past 30 years, tubular daylight guide systems (TDGSs) have become one of the most popular ways to transport outdoor natural light into the inner space in building design. However, tubular daylight guide systems are not widely used because of the lack of methods to evaluate methods on the suitability of the TDGSs. This study therefore summarizes the daylight performance metrics of TDGSs and presents the estimation methods in terms of field measurements, simulation and empirical formulae. This study focuses on the daylight performance and potential energy savings of TDGSs. Moreover, this study will be helpful for building designers to build healthy, comfortable and energy-saving indoor environment.

scholarly journals Evaluating the performance of multivariate indicators of resilience loss

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Els Weinans ◽  
Rick Quax ◽  
Egbert H. van Nes ◽  
Ingrid A. van de Leemput
Keyword(s):  
Time Series ◽  
Complex Systems ◽  
Multivariate Time Series ◽  
Tipping Points ◽  
Physical And Mental Health ◽  
One Dimensional ◽  
Slowing Down ◽  
The Past ◽  
Technological Developments ◽  
Resilience Indicators

AbstractVarious complex systems, such as the climate, ecosystems, and physical and mental health can show large shifts in response to small changes in their environment. These ‘tipping points’ are notoriously hard to predict based on trends. However, in the past 20 years several indicators pointing to a loss of resilience have been developed. These indicators use fluctuations in time series to detect critical slowing down preceding a tipping point. Most of the existing indicators are based on models of one-dimensional systems. However, complex systems generally consist of multiple interacting entities. Moreover, because of technological developments and wearables, multivariate time series are becoming increasingly available in different fields of science. In order to apply the framework of resilience indicators to multivariate time series, various extensions have been proposed. Not all multivariate indicators have been tested for the same types of systems and therefore a systematic comparison between the methods is lacking. Here, we evaluate the performance of the different multivariate indicators of resilience loss in different scenarios. We show that there is not one method outperforming the others. Instead, which method is best to use depends on the type of scenario the system is subject to. We propose a set of guidelines to help future users choose which multivariate indicator of resilience is best to use for their particular system.

2D Self-assembly and Electronic Characterization of Oxygen-Boron-Oxygen-Doped Chiral Graphene Nanoribbons

2021 ◽  
Author(s):  
Lei Jin ◽  
Nerea Bilbao ◽  
Yang Lv ◽  
Xiao-Ye Wang ◽  
Soltani Paniz ◽  
...  
Keyword(s):  
Edge Effects ◽  
Self Assembly ◽  
Quantum Confinement ◽  
Graphene Nanoribbons ◽  
One Dimensional ◽  
The Past ◽  
Different Types

Graphene nanoribbons (GNRs), quasi-one-dimensional strips of graphene, exhibit a nonzero bandgap due to quantum confinement and edge effects. In the past decade, different types of GNRs with atomically precise structures...

The Structure of Emotional Response: 1984 Presidential Candidates

1988 ◽  
Vol 82 (3) ◽  
pp. 737-761 ◽  
Author(s):  
George E. Marcus
Keyword(s):  
Emotional Response ◽  
Two Dimensions ◽  
Negative Emotionality ◽  
One Dimensional ◽  
Presidential Candidates ◽  
The Past ◽  
Emotional Appraisal ◽  
Psychological Models ◽  
Dimensional Models ◽  
Feeling Thermometer

Over the past two decades psychological models of affect have changed from valence (one-dimensional) models to multiple-dimensional models. The most recent models, circumplex models, are two-dimensional. Feeling thermometer measures, which derive their theoretical logic from earlier (valence) models of emotional appraisal, are shown to be confounded. Underlying the variation obtained using feeling thermometer measures are two dimensions of emotional response, mastery (positive emotionality) and threat (negative emotionality). Analysis of the 1984 NES survey suggests that positive emotional response is twice as influential as negative emotional response in predicting presidential candidate vote disposition to the presidential candidates. Reliance on emotional response is shown to be uniformly influential across various strata of the electorate.Policy considerations have little direct influence on vote disposition, though policy considerations are indirectly related to vote disposition through the influence of issues on the degree of feelings of threat evoked by the candidates.

The hidden layers of microbial community structure: extracting the concealed diversity dimensions from our sequencing data

2020 ◽  
Vol 367 (11) ◽  
Author(s):  
Andrea Fasolo ◽  
Laura Treu ◽  
Piergiorgio Stevanato ◽  
Giuseppe Concheri ◽  
Stefano Campanaro ◽  
...  
Keyword(s):  
Sequencing Data ◽  
16S Sequencing ◽  
Evolutionary Aspect ◽  
One Dimensional ◽  
Sequence Identity ◽  
The Past ◽  
Environmental Processes ◽  
Final Layer ◽  
Evolutionary Success ◽  
Microbial Groups

ABSTRACT Microbial metabarcoding is the standard approach to assess communities’ diversity. However reports are often limited to simple OTU abundances for each phylum, giving rather one-dimensional views of microbial assemblages, overlooking other accessible aspects. The first is masked by databases incompleteness; OTU picking involves clustering at 97% (near-species) sequence identity, but different OTUs regularly end up under a same taxon name. When expressing diversity as number of obtained taxonomical names, a large portion of the real diversity lying within the data remains underestimated. Using the 16S sequencing results of an environmental transect across a gradient of 17 coastal habitats we first extracted the number of OTUs hidden under the same name. Further, we observed which was the deepest rank yielded by annotation, revealing for which microbial groups are we missing most knowledge. Data were then used to infer an evolutionary aspect: what is, in each phylum the success of the present time individuals (abundances for each OTU) in relation to their prior evolutionary success in differentiation (number of OTUs). This information reveals whether the past speciation/diversification force is matched by the present competitiveness in reproduction/persistence. The final layer explored is functional diversity, i.e. abundances of groups involved in specific environmental processes.

Size and shape-controlled synthesis of Ru nanocrystals

2018 ◽  
Vol 3 (12) ◽  
Author(s):  
Linlin Xu ◽  
Jun Yang
Keyword(s):  
Noble Metal ◽  
Chemical Properties ◽  
Controlled Synthesis ◽  
One Dimensional ◽  
Size And Shape ◽  
The Past ◽  
Metal Nanomaterials ◽  
Shape Controlled ◽  
Synthetic Approaches ◽  
Coherent Picture

Abstract Mastery over the size/shape of nanocrystals (NCs) enables control of their properties and enhancement of their usefulness for a given application. Within the past decades, the development of wet-chemistry methods leads to the blossom of research in noble metal nanomaterials with tunable sizes and shapes. We herein would prefer to devote this chapter to introduce the solution-based methods for size and shape-controlled synthesis of ruthenium (Ru) NCs, which can be summarized into five categories: (i) Synthesis of spherical Ru NCs; (ii) synthesis of one-dimensional (1D) Ru NCs, e.g. wires and rods; (iii) synthesis of two-dimensional (2D) Ru NCs, e.g. nanoplates; (iv) synthesis of Ru NCs with hollow interiors and (v) synthesis of Ru NCs with other morphologies, e.g. chains, dendrites and branches. We aim at highlighting the synthetic approaches and growth mechanisms of these types of Ru NCs. We also introduce the detailed characterization tools for analysis of Ru NCs with different sizes/shapes. With respect to the creation of great opportunities and tremendous challenges due to the accumulation in noble metal nanomaterials, we briefly make some perspectives for the future development of Ru NCs so as to provide the readers a systematic and coherent picture of this promising field. We hope this reviewing effort can provide for technical bases for effectively designing and producing Ru NCs with enhanced physical/chemical properties. Graphical Abstract: The solution-based methods for size and shape-controlled synthesis of ruthenium nanocrystals as well as the mechanisms behind them are extensively reviewed.

Sign in / Sign up

Export Citation Format

Share Document