scholarly journals Modeling non-steady state radioisotope transport in the vadose zone – A case study using uranium isotopes at Peña Blanca, Mexico

2009 ◽  
Vol 73 (20) ◽  
pp. 6052-6064 ◽  
Author(s):  
T.L. Ku ◽  
S. Luo ◽  
S.J. Goldstein ◽  
M.T. Murrell ◽  
W.L. Chu ◽  
...  
Keyword(s):  
Steady State ◽  
Vadose Zone ◽  
Uranium Isotopes

Piezothermoelasticity and Control of Piezoelectric Laminates Exposed to a Steady-State Temperature Field

1993 ◽  
Author(s):  
H. S. Tzou ◽  
R. Ye
Keyword(s):  
Temperature Field ◽  
Steady State ◽  
Degrees Of Freedom ◽  
Sensors And Actuators ◽  
System Equation ◽  
Thermal Fields ◽  
Steady State Temperature ◽  
And Control ◽  
Internal Degrees Of Freedom

Abstract Piezothermoelastic effects of distributed piezoelectric sensors and actuators are investigated. Vibration control of piezoelectric laminates subjected to a steady-state temperature field is studied. A new 3-D piezothermoelastic finite element with three internal degrees of freedom is formulated using a variational formulation. A system equation for the piezoelectric continuum exposed to combined elastic, electric, and thermal fields is formulated. Distributed sensing and control equations are derived. All these effects are studied in a case study.

Impact of reactive settler models on simulated WWTP performance

2006 ◽  
Vol 53 (1) ◽  
pp. 159-167 ◽  
Author(s):  
K.V. Gernaey ◽  
U. Jeppsson ◽  
D.J. Batstone ◽  
P. Ingildsen
Keyword(s):  
Steady State ◽  
Treatment Plant ◽  
Simulation Studies ◽  
Plant Model ◽  
Model Simulations ◽  
N Removal ◽  
Whole Plant ◽  
Model Block ◽  
Simulation Results

Including a reactive settler model in a wastewater treatment plant model allows representation of the biological reactions taking place in the sludge blanket in the settler, something that is neglected in many simulation studies. The idea of including a reactive settler model is investigated for an ASM1 case study. Simulations with a whole plant model including the non-reactive Takács settler model are used as a reference, and are compared to simulation results considering two reactive settler models. The first is a return sludge model block removing oxygen and a user-defined fraction of nitrate, combined with a non-reactive Takács settler. The second is a fully reactive ASM1 Takács settler model. Simulations with the ASM1 reactive settler model predicted a 15.3% and 7.4% improvement of the simulated N removal performance, for constant (steady-state) and dynamic influent conditions respectively. The oxygen/nitrate return sludge model block predicts a 10% improvement of N removal performance under dynamic conditions, and might be the better modelling option for ASM1 plants: it is computationally more efficient and it will not overrate the importance of decay processes in the settler.

scholarly journals Composing Problem Solvers for Simulation Experimentation: A Case Study on Steady State Estimation

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e91948 ◽  
Author(s):  
Stefan Leye ◽  
Roland Ewald ◽  
Adelinde M. Uhrmacher
Keyword(s):  
Steady State ◽  
State Estimation ◽  
Problem Solvers

The Mechanics of a Helically Wrapped Thin-Shell Supported by an Externally Pressurized Air Cushion

2002 ◽  
Author(s):  
Sinan Mu¨ftu¨
Keyword(s):  
Steady State ◽  
Thin Shell ◽  
Previous Model ◽  
Fluid Structure Interactions ◽  
Oblique Angle ◽  
Equilibrium Equations ◽  
State Equilibrium ◽  
Air Cushion ◽  
The Web

The mechanics of the fluid structure interactions between a flexible web and an externally pressurized air cushion is modeled. The web is wrapped around the porous cylindrical air-reverser at an oblique angle. The air reverser supplies pressurized air into the web/air-reverser clearance. This model is an extension of a previous model and allows the web to be wrapped around the cylinder in a helical fashion. The geometric relations are based on Rongen’s work (1994) and steady state equilibrium equations are developed based on the work of Mu¨ftu¨ and Cole (1999). This paper describes the theory. A case study is presented.

scholarly journals Sensitivity of Characterizing the Heat Loss Coefficient through On-Board Monitoring: A Case Study Analysis

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3322 ◽  
Author(s):  
Marieline Senave ◽  
Staf Roels ◽  
Stijn Verbeke ◽  
Evi Lambie ◽  
Dirk Saelens
Keyword(s):  
Sensitivity Analysis ◽  
Steady State ◽  
Data Analysis ◽  
Heat Loss ◽  
Input Data ◽  
Loss Coefficient ◽  
Wide Range ◽  
Board Monitoring ◽  
The Impact

Recently, there has been an increasing interest in the development of an approach to characterize the as-built heat loss coefficient (HLC) of buildings based on a combination of on-board monitoring (OBM) and data-driven modeling. OBM is hereby defined as the monitoring of the energy consumption and interior climate of in-use buildings via non-intrusive sensors. The main challenge faced by researchers is the identification of the required input data and the appropriate data analysis techniques to assess the HLC of specific building types, with a certain degree of accuracy and/or within a budget constraint. A wide range of characterization techniques can be imagined, going from simplified steady-state models applied to smart energy meter data, to advanced dynamic analysis models identified on full OBM data sets that are further enriched with geometric info, survey results, or on-site inspections. This paper evaluates the extent to which these techniques result in different HLC estimates. To this end, it performs a sensitivity analysis of the characterization outcome for a case study dwelling. Thirty-five unique input data packages are defined using a tree structure. Subsequently, four different data analysis methods are applied on these sets: the steady-state average, Linear Regression and Energy Signature method, and the dynamic AutoRegressive with eXogenous input model (ARX). In addition to the sensitivity analysis, the paper compares the HLC values determined via OBM characterization to the theoretically calculated value, and explores the factors contributing to the observed discrepancies. The results demonstrate that deviations up to 26.9% can occur on the characterized as-built HLC, depending on the amount of monitoring data and prior information used to establish the interior temperature of the dwelling. The approach used to represent the internal and solar heat gains also proves to have a significant influence on the HLC estimate. The impact of the selected input data is higher than that of the applied data analysis method.

Wastewater treatment by infiltration percolation: a case study

2000 ◽  
Vol 41 (1) ◽  
pp. 77-84 ◽  
Author(s):  
V. Mottier ◽  
F. Brissaud ◽  
P. Nieto ◽  
Z. Alamy
Keyword(s):  
Vadose Zone ◽  
High Water ◽  
Faecal Coliforms ◽  
Dune Sands ◽  
Seaside Resort ◽  
Load Monitoring ◽  
Oxidation Performance ◽  
Kinetics Of ◽  
Stock Recovery

A 1700 p.e. pilot infiltration percolation plant treating the sewage of Mazagon, a seaside resort in the South of Spain, is investigated. Primary effluents, intermittently applied over twin 200 m2 infiltration basins, percolate down to the aquifer through unsaturated dune sands. Each application sequence delivers a volume of 0.25 m3 per m2 of infiltration basin. Analyses of the water sampled at five depths ranging from 0.3 to 2.0 m below the infiltration surface show that the oxidation performance of the plant is highly dependent on the applied load. Monitoring the oxygen content in the air phase of the vadose zone allows to determine the kinetics of the oxygen stock recovery and the oxidation capacity of the plant. Disappointing removal of faecal coliforms and streptococci is attributed to high pore water velocities due to infiltration heterogeneity and the high water height applied during each feeding sequence.

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