scholarly journals A new sewage exfiltration model – parameters and calibration

2011 ◽  
Vol 63 (10) ◽  
pp. 2294-2299 ◽  
Author(s):  
Christian Karpf ◽  
Peter Krebs
Keyword(s):  
Waste Water ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Experimental Studies ◽  
Model Parameters ◽  
Potential Danger ◽  
Detailed Consideration ◽  
Sewer Systems ◽  
The Law ◽  
Groundwater Infiltration

Exfiltration of waste water from sewer systems represents a potential danger for the soil and the aquifer. Common models, which are used to describe the exfiltration process, are based on the law of Darcy, extended by a more or less detailed consideration of the expansion of leaks, the characteristics of the soil and the colmation layer. But, due to the complexity of the exfiltration process, the calibration of these models includes a significant uncertainty. In this paper, a new exfiltration approach is introduced, which implements the dynamics of the clogging process and the structural conditions near sewer leaks. The calibration is realised according to experimental studies and analysis of groundwater infiltration to sewers. Furthermore, exfiltration rates and the sensitivity of the approach are estimated and evaluated, respectively, by Monte-Carlo simulations.

Impact of sewer condition on urban flooding: an uncertainty analysis based on field observations and Monte Carlo simulations on full hydrodynamic models

2012 ◽  
Vol 65 (12) ◽  
pp. 2219-2227 ◽  
Author(s):  
M. van Bijnen ◽  
H. Korving ◽  
F. Clemens
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Surface Damage ◽  
Model Parameters ◽  
Field Observations ◽  
Sewer System ◽  
Sewer Systems ◽  
Calculation Results ◽  
Urban Pluvial Flooding ◽  
The Impact

In-sewer defects are directly responsible for affecting the performance of sewer systems. Notwithstanding the impact of the condition of the assets on serviceability, sewer performance is usually assessed assuming the absence of in-sewer defects. This leads to an overestimation of serviceability. This paper presents the results of a study in two research catchments on the impact of in-sewer defects on urban pluvial flooding at network level. Impacts are assessed using Monte Carlo simulations with a full hydrodynamic model of the sewer system. The studied defects include root intrusion, surface damage, attached and settled deposits, and sedimentation. These defects are based on field observations and translated to two model parameters (roughness and sedimentation). The calculation results demonstrate that the return period of flooding, number of flooded locations and flooded volumes are substantially affected by in-sewer defects. Irrespective of the type of sewer system, the impact of sedimentation is much larger than the impact of roughness. Further research will focus on comparing calculated and measured behaviour in one of the research catchments.

Hydraulic modelling of sewage exfiltration

2009 ◽  
Vol 59 (8) ◽  
pp. 1559-1565 ◽  
Author(s):  
Christian Karpf ◽  
Jens Traenckner ◽  
Peter Krebs
Keyword(s):  
Waste Water ◽  
Temporal Variation ◽  
Spatial And Temporal Variation ◽  
Potential Danger ◽  
Hydraulic Modelling ◽  
Detailed Consideration ◽  
Matrix Potential ◽  
The Matrix ◽  
Sewer Networks ◽  
Hydrus 1D

Exfiltration of waste water in sewer networks represents a potential danger for the soil and the aquifer. Various modelling approaches have been proposed to quantify sewerage exfiltration and its spatial and temporal variation. Common models are based on the law of Darcy, extended by a more or less detailed consideration of the expansion of leaks, the characteristics of the soil and the colmation layer. In the paper investigations are introduced, which are focused on the actual water content of the soil and its influence on exfiltration rates. Modelling results with HYDRUS 1D show, that under unsaturated conditions initial exfiltration rates are increased compared to saturated conditions. In experiments it was found, that the matrix potential increases the tightness of the colmation layer. Further a colmation model was deduced, which allows the calculation of the thickness and conductivity of the colmation layer.

SIMULATIONS OF GLYCOLYTIC OSCILLATIONS IN CELLS WITH COMPARTMENTS

2002 ◽  
Vol 12 (07) ◽  
pp. 1643-1652 ◽  
Author(s):  
VLADIMIR P. ZHDANOV
Keyword(s):  
Monte Carlo ◽  
Cell Membrane ◽  
Monte Carlo Simulations ◽  
Cell Size ◽  
Elementary Reaction ◽  
Model Parameters ◽  
Typical Size ◽  
Glycolytic Oscillations ◽  
Glucose Supply ◽  
In Cells

We present Monte Carlo simulations of glycolytic oscillations inside the cell with a chemically inactive compartment. The model employed takes into account the glucose supply to the cell via the cell membrane and a few elementary reaction steps running inside the cell in the area between the external membrane and the compartment. The model parameters are chosen so that the typical size of oscillatory patterns is comparable with the cell size. Although the compartment does not directly participate in the reaction, its presence is found to amplify irregular oscillations provided that the compartment size is appreciable and it is located in the center of the cell.

Specifying Weights in Spatial Forecasting Models: The Results of Some Experiments

1982 ◽  
Vol 14 (5) ◽  
pp. 571-584 ◽  
Author(s):  
F Stetzer
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Weight Function ◽  
Effective Area ◽  
Space Time ◽  
Distance Decay ◽  
Model Parameters ◽  
Sample Sizes ◽  
Forecasting Models ◽  
Estimation Of Model Parameters

The application of space-time forecasting models requires the specification of a set of place-to-place weights. The existing literature contains several recommendations for this specification. By a series of Monte Carlo simulations, various weighting rules are compared in terms of estimation of model parameters and accuracy of forecasts. It is shown that specification of the weights is important, especially when sample sizes are small and the data autocorrelated. Generally, the effective area of the weight function is more important than its distance decay.

scholarly journals Uncertainty analysis of rising sewer models with respect to input parameters and model structure using Monte Carlo simulations and computational fluid dynamics

2021 ◽  
Author(s):  
Ahmed Khalil ◽  
Domenico Santoro ◽  
Damien J. Batstone ◽  
Christopher T. DeGroot
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Model Parameters ◽  
Model Structure ◽  
Mathematical Form ◽  
Homogeneous Surface ◽  
Simple Flows ◽  
D Model

Abstract Modelling conversion processes in sewers can help minimize odour and pipe corrosion issues, but model uncertainties and errors must be understood. In this study, the Wastewater Aerobic/Anaerobic Transformation in Sewers (WATS) model is implemented in two different frameworks; 1-D (CSTR-in-series) and computational fluid dynamics (CFD) to study the uncertainties due to model parameters and its mathematical form. The 1-D model is used to conduct uncertainty/sensitivity analysis using Monte Carlo simulations. Time-averaged outputs were represented using a general linearized model to quantify the importance of specific parameters. The sulfide formation rate per unit area of the biofilm is the most influential parameter. Parameters controlling anaerobic hydrolysis and fermentation are also significant. Uncertainty due to model structure is studied using CFD to explore the influences of non-homogeneous surface reactions and solids settling. These showed that the 1-D model provides a reasonable characterisation of the process for simple flows in pressure mains.

scholarly journals Impact of model parameters on Monte Carlo simulations of backscattering Mueller matrix images of colon tissue

2011 ◽  
Vol 2 (7) ◽  
pp. 1836 ◽  
Author(s):  
Maria-Rosaria Antonelli ◽  
Angelo Pierangelo ◽  
Tatiana Novikova ◽  
Pierre Validire ◽  
Abdelali Benali ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Mueller Matrix ◽  
Model Parameters ◽  
Colon Tissue

Polymers in Concrete – The Shielding against Neutron Radiation

2015 ◽  
Vol 1129 ◽  
pp. 131-138 ◽  
Author(s):  
Tomasz Piotrowski ◽  
Dariusz B. Tefelski ◽  
Michał Mazgaj ◽  
Janusz Skubalski ◽  
Andrzej Żak ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Experimental Studies ◽  
Neutron Radiation ◽  
High Energy ◽  
Fast Neutrons ◽  
Final Conclusion ◽  
Concrete Technology ◽  
Neutron Shielding ◽  
Neutron Attenuation

Concrete has been used as a shield against high-energy photons (gamma) and neutrons since the beginning of use of nuclear reaction in energy, medicine and research. State of knowledge in shielding concrete technology is that while in case of protection against gamma radiation an increase in density caused by change of aggregate type for heavy-weight one is usually an efficient solution, the protection against neutrons is more complex. It is due to the differences in interactions of neutrons with the matter, depending on their kinetic energy and cross-sections for different reactions of the component atoms of the cement paste and the aggregate. The paper presents the results of the project NGS-Concrete - New-Generation Shielding Concrete. The aim is to design the composition of concrete against ionizing radiation, achieved by the use of experiment based on multi-criteria optimization of materials supported by the Monte Carlo simulations. Better concrete is the one that absorbs more thermal neutrons and slows down more fast neutrons at the same time. In the paper both results of Monte Carlo simulations and experimental studies on ordinary and heavyweight concrete containing epoxy polymer additive are presented. Close values of thermal neutron attenuation coefficients proved good accordance between simulation and experiment. The final conclusion is that epoxy resin is an efficient additive for neutron shielding concretes improving its ability to protect mainly against low energy neutrons. In experimental measurement there has not been observed an improvement of fast neutron attenuation due to increase of hydrogen atom content introduced with epoxy.

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