2D simulation of transport and degradation in the River Rhine

2002 ◽  
Vol 46 (6-7) ◽  
pp. 99-104
Author(s):  
L. Teichmann ◽  
P. Reuschenbach ◽  
B. Müller ◽  
H. Horn
Keyword(s):  
Mass Transport ◽  
Flow Direction ◽  
River Rhine ◽  
Exchange Coefficient ◽  
River Bank ◽  
Environmental Concentration ◽  
First Order ◽  
2D Simulation ◽  
Degradation Term ◽  
The Eu

A simple 2D model has been developed for the simulation of mass transport and degradation of substances in the river Rhine. The model describes mass transport in the flow direction with a convective and a dispersive term. Transversal transport is described by segmenting the river and formulating a transversal exchange coefficient between the segments. Degradation can be formulated with any kinetics from first order to complex enzyme kinetics. The model was verified with monitoring data from the river Rhine. The hydrodynamic parameters such as dispersion coefficients and exchange coefficients were fitted to the conductivity, which was assumed to be non-degradable. The degradation term was fitted to ammonia values. The model was used to simulate measured concentrations of a readily (Aniline) and a poorly biodegradable substance (1,4-Dioxan) 10 m from the left river bank. It was the objective of this research program to develop a model which allows a realistic estimation of the locally and regionally predicted environmental concentration of chemical substances in the EU risk assessment scheme.

scholarly journals Mass transport deposits in the Donegal Barra Fan and their association with British–Irish Ice Sheet dynamics

2020 ◽  
Vol 500 (1) ◽  
pp. 567-586 ◽  
Author(s):  
Srikumar Roy ◽  
Aggeliki Georgiopoulou ◽  
Sara Benetti ◽  
Fabio Sacchetti
Keyword(s):  
Mass Transport ◽  
Continental Margin ◽  
Flow Direction ◽  
Thickness Distribution ◽  
Ice Sheet ◽  
High Mobility ◽  
Stacking Pattern ◽  
Local Erosion ◽  
Ice Sheet Dynamics ◽  
Mass Transport Deposits

AbstractThis study analyses seismic data to investigate the kinematic indicators within the mass transport deposits (MTDs) of the Donegal Barra Fan complex in the Rockall Trough, along the NW European continental margin. Five episodes of mega-scale MTDs (DBF-01, -02, -03, -04 and -05) are identified. DBF-01 is the largest MTD in the NW British continental margin, comprising 1907 km3 of sediments. Fold-and-thrusts were identified within the MTDs where they attain maximum thickness of c. 300–380 ms TWT, but not at the toe region. This indicates that local erosion and deceleration caused bulking up of the MTD volume, but the MTD was not fully arrested due to the high mobility of the mass flow. MTD thickness distribution and thrust fault orientations indicate source areas and flow direction of MTD. The MTDs show a compensational stacking pattern with earlier deposits influencing the position and flow direction of succeeding slides, suggesting that glaciogenic debris flows are sensitive to topographic variability. We propose that increased sediment input associated with at least five expansions of the British–Irish Ice Sheet to the shelf edge led to the development of these MTDs and that the youngest of them, DBF-05, corresponds to the Last Glacial Maximum.

Study on the Effects of Nitrogen Pollution to the Soil and Groundwater

2013 ◽  
Vol 437 ◽  
pp. 1019-1022 ◽  
Author(s):  
Xiao Hui Lu ◽  
Yang Wang
Keyword(s):  
Nitrogen Content ◽  
Nitrate Nitrogen ◽  
Flow Direction ◽  
Ammonium Nitrogen ◽  
Nitrogen Pollution ◽  
Monitoring Point ◽  
River Bank ◽  
The North ◽  
Geological Conditions ◽  
Nitrite Nitrate

Xuzhou city lies on the north of Jiangsu province, which geological conditions are complex, water resources are deficient and environment is vulnerable. At present, water pollution in Kui river area is very serious; Kui River nitrogen pollution had affected Coastal soil and chemical environment of groundwater. The monitoring sections are elected in the seriously polluted river, and downstream at the banks of river decorates with six monitoring sections. Each section from the river bank of 50m, 100m, 200m, 500m, 1000m, 1500m is arranged of monitoring points respectively, and each monitoring point is monitored for sampling test at different depths. The monitoring results of surface water showed that the content of ammonia-nitrite-nitrate was a decreasing trend along the flow direction. The nitrate nitrogen content would decrease further in December while the ammonium nitrogen content was on the rise, showing that the supplement of nitrogen pollution resources was still insufficient when the denitrification was stronger. The content of ammonium and nitrate nitrogen in soil was higher, and had some regular change features with the change of depth.

scholarly journals Thickness Optimisation of Textiles Subjected to Heat and Mass Transport during Ironing

2016 ◽  
Vol 16 (3) ◽  
pp. 165-174 ◽  
Author(s):  
Ryszard Korycki ◽  
Halina Szafranska
Keyword(s):  
Mass Transport ◽  
Initial Conditions ◽  
Phase System ◽  
Two Phase ◽  
Textile Materials ◽  
First Order ◽  
Coupled Problem ◽  
Physical And Mathematical Models ◽  
Optimisation Procedure ◽  
Objective Functional

Abstract Let us next analyse the coupled problem during ironing of textiles, that is, the heat is transported with mass whereas the mass transport with heat is negligible. It is necessary to define both physical and mathematical models. Introducing two-phase system of mass sorption by fibres, the transport equations are introduced and accompanied by the set of boundary and initial conditions. Optimisation of material thickness during ironing is gradient oriented. The first-order sensitivity of an arbitrary objective functional is analysed and included in optimisation procedure. Numerical example is the thickness optimisation of different textile materials in ironing device.

Effect of Velocity-Slip Boundary Conditions on Jeffery–Hamel Flow Solutions

2010 ◽  
Vol 77 (4) ◽  
Author(s):  
M. A. Al-Nimr ◽  
Vladimir A. Hammoudeh ◽  
M. A. Hamdan
Keyword(s):  
Friction Coefficient ◽  
Skin Friction ◽  
Flow Direction ◽  
Velocity Slip ◽  
Skin Friction Coefficient ◽  
Second Order ◽  
Slip Model ◽  
Wall Angle ◽  
First Order ◽  
Slip Boundary

In the present work, the Jeffery–Hamel flow problem has been studied using both first- and second-order velocity-slip models, and then compared with the no-slip model. The objectives are to observe the behavior of the flow predicted by the two slip models and to establish criteria for using the two velocity-slip models. The study concentrates on examining the effect of the change in the Knudsen number (Kn) on the velocity profiles, magnitude of slip at the wall, and skin friction coefficient. Assuming that a difference between the two slip models of the order of 10% or less justifies the use of the simple first-order model, the transitional Kn numbers have been found. These Kn numbers depend on the flow direction, being either inflow or outflow. Also, there are three distinct regions that specify where to use each of the no-slip, first-order, and second-order slip models. Further, the reversal of the flow has been investigated as a function of the Kn number and for different Re⋅α, where Re is Reynolds number and α is the wall angle. Using the second-order slip models, it is found that as the Kn number increases, reversal occurs at Re⋅α smaller than the 10.31 value at which flow reversal happens in the no-slip model, and increasing the Kn number leads to a reduction in the skin friction coefficient in all cases except when reversal occurs.

scholarly journals An Analytical Study on Wave-Current-Mud Interaction

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2899
Author(s):  
S. Shamsnia ◽  
Denys Dutykh
Keyword(s):  
Mass Transport ◽  
Current Velocity ◽  
Analytical Study ◽  
Laboratory Data ◽  
Second Order ◽  
Mean Velocity ◽  
First Order ◽  
Dissipation Rates ◽  
Proposed Model ◽  
Interaction Problem

This study aims at providing analytical investigations to the first and second-order on the wave–current–mud interaction problem by applying a perturbation method. Direct formulations of the wave–current–mud interaction could not be found in the literature. Explicit formulations for the particle velocity, dissipation rates, and phase shift in the first order and the mass transport in the second-order have been obtained. The findings of the current study confirmed that by an increase in the current velocity (e.g., moving from negative to positive values of current velocity), the dissipation rates and mud (instantaneous and mean) velocity decrease. The proposed assumption of a thin mud layer (boundary layer assumption) matches with the laboratory data in the mud viscosity of the orders of (0.01 N/m2) in both wave dissipation and mud mass transport leading to small ranges of discrepancies. The results from the newly proposed model were compared with the measurements and the results of an existing model in the literature. The proposed model showed better agreements in simulating the mud (instantaneous and mean) velocity compared to the existing one.

Market Discipline

2019 ◽  
pp. 110-130
Author(s):  
Charlotte Rommerskirchen
Keyword(s):  
Fiscal Policy ◽  
Free Riding ◽  
Policy Coordination ◽  
Market Discipline ◽  
Second Order ◽  
Fiscal Rules ◽  
Member States ◽  
First Order ◽  
Fiscal Policy Coordination ◽  
The Eu

Free riding is endemic. But it is not the type of first-order free riding that politicians and EU officials publicly chastised. Instead, fiscal policy coordination is burdened by a serious internal enforcement problem; that is, second-order free riding. The argument presented here is different from the usual decrying of a lack of enforcement in fiscal policy coordination, which is said to invite member states to engage in rampant fiscal free riding. This chapter contests that without internal enforcement within the EU, fiscal policy coordination has come to rely on market discipline with dire consequences for its members. The chapter demonstrates that, in contrast to fiscal rules and intergovernmental agreements, the incentives provided by market discipline shape public finances.

Bridge over the Vistula river in Toruń (Poland)

2019 ◽  
Author(s):  
Krzysztof Wachalski
Keyword(s):  
Horizontal Force ◽  
Original Solution ◽  
River Bank ◽  
Arch Bridge ◽  
Vistula River ◽  
Bridge Crossing ◽  
Slide Material ◽  
Structural Scale ◽  
Engineering Projects ◽  
The Eu

<p>The construction of the arch bridge in Toruń was one of the greatest and more spectacular engineering projects implemented during the recent years. In December 2013 the Poland’s largest arch bridge was completed and opened. The bridge has two spans, 270m long each, and is used as a bridge crossing over the Vistula river (Fig.1). The bridge is over 1.9 km long counting the access overbridges (viaducts). The erection procedure of the bridge was unique and individual, as the structural scale suggests. Generally, the assembly covered junction of arch elements on the assembly site near the Vistula river bank and the pontoon water transport of arch girders, which were settled on the arch abutments. A unique affordable structural solution deals with the support footing of a great number of small concrete pre-cast piles transferring a giant horizontal force into the subsoil. The steel-arch is modeled by a hingeless system without a tie, transferring horizontal force into supports. A original solution of assembly geometry control system and monitoring system was applicate to floating erection. Innovation was done of introducing material for the pot bearings, whose durability was 5-times longer than the ordinary ones. A novel slide material PTFE was used, the so-called grey teflon of improved abrasion ability. The new PTFE solutions were recently applied for the spherical bearings, but never they have been for the pot bearings. The bearings worked out an individual product specification, based on experiments conducted in the EU laboratory. The world's pioneering enterprise is application of a hundred pot bearings for the bridge and viaducts.</p>

Influence of the first-order exchange coefficient on simulation of coupled surface–subsurface flow

2012 ◽  
Vol 414-415 ◽  
pp. 503-515 ◽  
Author(s):  
Jessica E. Liggett ◽  
Adrian D. Werner ◽  
Craig T. Simmons
Keyword(s):  
Subsurface Flow ◽  
Exchange Coefficient ◽  
First Order

Phase Diagram of Spin States and Magnetic Interactions in Isotope Substituted (Pr,Eu)0.7Ca0.3CoO3

2010 ◽  
Vol 168-169 ◽  
pp. 465-468
Author(s):  
A.V. Kalinov ◽  
O.Yu. Gorbenko ◽  
A.N. Taldenkov ◽  
J. Rohrkamp ◽  
O. Heyer ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Spin State ◽  
Magnetic Ordering ◽  
Double Exchange ◽  
Magnetic Interactions ◽  
First Order ◽  
Spin State Transition ◽  
Intermediate Spin ◽  
Magnetic Spin ◽  
The Eu

The magnetic/spin-state phase diagram of the (Pr1-yEuy)0.7Ca0.3CoO3 series was obtained on the basis of measurements of the specific heat, thermal expansion, magnetization and resistivity. The phase diagram reveals three different states depending on the static distortions (Eu content), the oxygen-isotope mass, and the temperature. The samples with the lower Eu concentrations are ferromagnetically ordered up to moderate temperatures (about 50 K),, most probably, due to the low-spin Co4+ – intermediate-spin Co3+ interaction of the double-exchange type. As the Eu doping increases, the Co3+ LS (S = 0) state becomes stabilized and the magnetic ordering of the Co4+ ions is suppressed up to temperatures well below 5 K, resulting in a low-temperature anomaly in Cp. At higher temperatures, we observe a first-order spin-state transition from the LS to the IS state of Co3+, which is accompanied by a decrease in the electrical resistivity, an increase in the magnetization, and a strong lattice expansion.

Heat/mass transport in shear flow over a reactive surface with inert defects

2016 ◽  
Vol 811 ◽  
pp. 372-399 ◽  
Author(s):  
Preyas N. Shah ◽  
Tiras Y. Lin ◽  
Eric S. G. Shaqfeh
Keyword(s):  
Boundary Layer ◽  
Shear Flow ◽  
Mass Transport ◽  
Sherwood Number ◽  
Heterogeneous Reaction ◽  
Surface Concentration ◽  
Reaction Rates ◽  
First Order ◽  
Reactive Surface ◽  
Wide Range

We study the problem of mass transport to surfaces with heterogeneous reaction rates in the presence of shear flow over these surfaces. The reactions are first order and the heterogeneity is due to the existence of inert regions on the surfaces. Such problems are ubiquitous in the field of heterogeneous catalysis, electrochemistry and even biological mass transport. In these problems, the microscale reaction rate is characterized by a Damköhler number $\unicode[STIX]{x1D705}$, while the Péclet number $P$ is the dimensionless ratio of the bulk shear rate to the inverse diffusion time scale. The area fraction of the reactive region is denoted by $\unicode[STIX]{x1D719}$. The objective is to calculate the yield of reaction, which is directly related to the mass flux to the reactive region, denoted by the dimensionless Sherwood number $S$. Previously, we used boundary element simulations and examined the case of first-order reactive disks embedded in an inert surface (Shah & Shaqfeh J. Fluid Mech., vol. 782, 2015, pp. 260–299). Various correlations for the Sherwood number as a function of $(\unicode[STIX]{x1D705},P,\unicode[STIX]{x1D719})$ were obtained. In particular, we demonstrated that the ‘method of additive resistances’ provides a good approximation for the Sherwood number for a wide range of values of $(\unicode[STIX]{x1D705},P)$ for $0<\unicode[STIX]{x1D719}<0.78$. When $\unicode[STIX]{x1D719}\approx 0.78$, the reactive disks are in a close packed configuration where the inert regions are essentially disconnected from each other. In this work, we develop an understanding of the physics when $\unicode[STIX]{x1D719}>0.78$, by examining the inverse problem of inert disks on a reactive surface. We show that the method of resistances approach to obtain the Sherwood number fails in the limit as $\unicode[STIX]{x1D719}\rightarrow 1$, i.e. in the dilute limit of periodic inert disks, due to the existence of a surface concentration boundary layer around each disk that scales with ($1/\unicode[STIX]{x1D705}$). This boundary layer controls the screening length between inert disks and allows us to introduce a new theory, thus providing new correlations for the Sherwood number that are highly accurate in the limit of $\unicode[STIX]{x1D719}\rightarrow 1$.

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