2,378 Works

Sediment retention in rectangular storage tanks: Computations with a mass transport model and comparison with laboratory experiments.

M. Jensen
ABSTRACT A linear convection-dispersion-deposition model, in 1 length dimension (CDD1), for a rectangular storage tank, is applied for computing the variation, over distance and time, of the vertical mean concentration C of suspended sediment. It is assumed, that the deposition rate to the bottom is proportional to C. The deposition velocity Vp, is the constant of proportionality. The model is used, for steady tank flow velocity V, to calculate the mass distribution (suspended mass +...

CSO detention tanks in Barcelona: Real time control design and operation

I. Escaler, A. Gil, R. Guasch & J. M. Verdejo
The environmental concern in the sewerage field has led Barcelona to build and operate its first CSO (combined sewer overflow) detention tank. It has been built in the zone of Forum de les Cultures 2004 and its main objective is the environmental protection of the new area seafront. This tank will be part of the Remote Control System of Barcelona\342\200\231s sewer network so its regulation strategy has been designed. This paper presents the design process...

MEMS energy harvesters based on silicon and PZT thickfilm technology for wireless sensor systems

Anders Thyssen, Adam Stoot, Thomas Lehrmann Christiansen, Erik Vilain Thomsen & Karen Birkelund
In recent years, the concept of energy harvesting has attracted much attention. The basic idea is to scavenge or harvest energy from the ambient surroundings of a device, convert it into electrical energy and use it to power a device, typically a wireless sensor system. The energy harvester can thus be seen as a small local power plant which uses otherwise wasted energy in the form of vibrations, temperature differences etc. which are abundant in...

Mineral Grain Spatial Patterns and Reaction Rate Up-Scaling

Catherine Peters, Jason Lewandowski, Marissa Maier, Michael Celia, Li Li & Catherine Peters
Reactive transport models that describe mineral reactions in porous media rely on laboratory measurements of rate parameters that may fail to represent reactions defined at larger averaging scales. Laboratory experiments usually use crushed minerals in well-mixed systems that are designed to eliminate mass transport limitations. The resulting data provide valuable information on mineral reactivities but have questionable value for describing reaction rates in porous media in which mass transport may be rate-limiting. In recently completed...

Stochastic layering effect on the upward migration of anthropogenic CO2 sequestered in saline aquifers.

Andrea Comerlati, Alberto Bellin, Massimiliano Ferronato, Giuseppe Gambolati, Mario Putti, Pietro Teatini & Andrea Comerlati
A widespread concern among the scientific community is the increase of the greenhouse gas emissions, especially CO2, which may yield an increase of earth's temperature. To reduce the CO2 released in the atmosphere an option which is attracting a growing attention is its sequestration in deep geologic formations. Deep saline aquifers may offer a great potential for the storage of large volumes of carbon dioxide. However, because of the relatively small practical experience with CO2...

Anticipated challenges for cross-organisational distributed collaboration in reactive telemedicine

Kine REEGAARD, Espen NYSTAD, Alexandra FERNANDES & Grete RINDAHL
On the Norwegian Continental Shelf, several operators have invested in technologies that are enabling and enhancing real-time collaboration between personnel onshore and offshore in order to achieve more effective decision-making. This is thought to improve operational performance, including delivery of offshore healthcare. Frequently in offshore healthcare, distributed collaboration takes place between medical personnel belonging to different organisations. Despite advances in and use of collaboration technologies, there is still potential for improvements in the cross-organisational collaboration....

Airflow effects on the hygrothermal behaviour of lightweight wall structures

Joachim Verhaeghen, Staf Roels & Joachim Verhaeghen
Several research projects have already indicated the importance of airflow and air leakage when considering hygrothermal responses of building components. In order to study the influence of airflow on the hygrothermal behaviour of lightweight wall structures, a test-setup has been constructed at the K.U.Leuven Vliet test building. A terraced house has been built up. First measurements are carried out on the ground level part. The test-setup has two outer walls. The SW-wall is a cavity...

Stakeholder involvement in wastewater treatment design

D.J. Gilmour, D.J. Blackwood & K. Picken
The design option appraisal stage of new water industry capital investment projects involve greater levels of complexity than those generally encountered in other stages of the design process. It is at this stage that the issues related to sustainable development will be introduced, as decisions are multi-stakeholder and therefore decision criteria that reflect the views of a wide range of stakeholders with a range of different viewpoints need to be incorporated. This paper describes a...

Field monitoring and evaluation of the stormwater management StormFilter\302\256 in the State of Washington

J. H. Lenhart & S. De Ridder
In 2003 the Washington State Department of Ecology adopted new criteria defining a design storm and expected BMP removal performance. Ecology also formed a Technical Review Committee (TRC) to establish a protocol for evaluating BMPs, which became known as the \342\200\234Technology Acceptance Protocol\342\200\224Ecology\342\200\235 (TAPE). To gain approval a manufacturer prepares an application including a technology description, maintenance and cost information, laboratory and field data. Based on this application the TRC gives a designation. Technologies receiving...

On the issue of trend and noise in the estimation of extreme rainfall properties

W. Rauch & S. De Toffol
Up until today extreme rainfall properties are frequently applied in sewer design guidelines. Uncertainty in the estimation of such properties will hence directly influence the dimensions of sewers, structures and pumps. In this paper the issue of potential trend and noise in the estimation is investigated for 6 rain series from ranging from 19 to 55 years in duration. Different to recent research that predicts a - climate induced \342\200\223 increase in heavy precipitation no...

Investigating pore scale configurations of two immiscible fluids via Level Set Method

Masa Prodanovic, Steven L. Bryant & Masa Prodanovic
The study of pore level displacement of immiscible fluids has scientific appeal as well as a plethora of engineering applications, notably in oil reservoir engineering and in environmental problems in the shallow subsurface. Pore network models have been used for numerical simulation of fluid displacement over relevant physical volume sizes. An accurate description of the mechanics of 3D displacement could significantly improve the predictions from network models of capillary pressure - saturation curves, interfacial areas...

Decision support system for storm design level based on inundation damage simulation and risk analysis using GIS

M. Morita & K. Yamashita
To decide a storm design level for flood prevention in urban areas is a crucial task for local governmental engineers. The objective of this study is to present a risk analysis method for storm design level decisions. The concept of \342\200\234risk\342\200\235 is defined as the product of flood damage and its occurrence probability. The study also presents a flood damage prediction system using GIS to calculate flood damages for any design storms with different return...

Moisture and mould growth in compact roofs – Results from a three-stage field survey

Jonas Holme, Knut Noreng, Tore Kvande & Jonas Holme
Compact roof systems that are done right, using materials that are not mould-prone between a correctly installed vapour barrier and the roof waterproofing membrane, have typically been considered to be not very moisture sensitive. Moisture in compact roofs has therefore perhaps not received sufficient attention. With large precipitation amounts in southern Norway in the fall of 2000, the theme of built-in moisture in compact roofs became relevant. Both in connection with roof work during periods...

Two-phase stratified flows in downwardly inclined pipes. Linear stability analysis.

M. Mutti, G. Becciu & A. Paoletti
In free surface flow modelling, interactions between air and water are often neglected. However, considering the shear stresses at the air-water interface leads, on the one hand, to water depths which may be different from those predicted from standard single-phase models and, on the other, to a better identification of unstable flow conditions. In both cases, the differences can be relevant in testing sewer networks, especially when high water depths and flow rates are involved...

Water absorption in two-layer masonry systems - properties, profiles and predictions

Peter Johansson, Lars-Olof Nilsson & Peter Johansson
Non-steady state water transport through two different mortars on lime-sand bricks has been studied to assess the possibilities of predicting moisture conditions in two-layer masonry systems in the super-hygroscopic range. Overlapping sorption and suction curves were determined by sorption balances and suction plates for the three materials. Moisture-dependent diffusivities were evaluated from series of capillary suction tests with different initial conditions. Predictions with RH as transport potential were then compared with the results from separate...

Improved Well Modeling Tools for Unsaturated Flow Pump-and-Treat Remediation Studies

Fred Tracy, Barbara Donnell, Stacy Howington, John Peters & Fred Tracy
Many Department of Defense military sites and Environmental Protection Agency superfund sites benefit from pump-and-treat systems for their remediation. One of the ways used to determine the effectiveness of a pump-and-treat system is by using a groundwater finite element method program to compute flow patterns from proposed well placement. As the governing Richards’ equation for unsaturated flow is highly nonlinear, the finite element discretization often has trouble converging. This is especially true when (1) a...

Path-averaged rainfall estimation using a microwave link: uncertainty due to rainfall spatial variability

Alexis Berne, Remko Uijlenhoet, Hidde Leijnse & Alexis Berne
Microwave links offer the possibility to estimate (1) the latent and sensible heat fluxes between land-surface and atmosphere, as well as (2) the path-averaged rainfall intensity along the link when precipitation occurs. In the latter case, a power-law relation is assumed between the specific attenuation k affecting the electro-magnetic signal while propagating through precipitation and the rainfall intensity R, variable of interest for many hydrological applications. This work focuses on the influence of the spatial...

Phenomenological modeling of wastewater treatment plant influent disturbance scenarios

K. V. Gernaey, C. Rosen, L. Benedetti & U. Jeppsson
Deterministic wastewater treatment plant (WWTP) models are useful for simulation-based evaluation of design, upgrade and control alternatives on WWTP performance. However, due to high requirements of measurement campaigns in terms of time and economic resources, many simulation studies suffer from the limited availability of long influent flow rate and concentration time series representing realistic influent disturbance scenarios. In this paper, a phenomenological modeling approach for generation of WWTP influent disturbance scenarios is proposed, with focus...

Foundations for a new type of design-engineers – experiences from DTU

Ulrik Jørgensen, Hanne Lindegaard & Søsser Brodersen
A new design engineering program at DTU starting in 2002 is presented with emphasis of the core disciplinary components and the integration of curriculum elements into a complete program. Evaluations have demonstrated some of the success factors than can provide radical reform in engineering education.

Peer Evaluation of Master Programs - Closing the Quality Circle of the CDIO approach?

Peter Munkebo Hussmann, Anita Bisi, Johan Malmqvist, Birgitta Carlsson, Hilde Lysne & Anna-Karin Högfeldt
This paper describes a Quality Assurance project which is conducted within the Nordic Five Tech (N5T) Alliance, a strategic alliance of the five leading technical universities in Denmark, Finland, Norway and Sweden. The project is concerned with the development of a quality enhancement tool. The tool is described and its impact on curriculum development quality of teaching and learning within the involved programs is analysed. The paper argues how international peer evaluation contribute to closing...

Historical overview of the Copenhagen sewerage system

S. S\303\270rensen, B. Petersen, N. Kofod & P. Jakobsen
The Copenhagen sewerage system was established in 1857. Thus, in 2007 we celebrate our 150th anniversary. Previous to the establishment there were some years of discussion of the principle \342\200\223 combined vs. separate sewer network. Most of the sewer network we know today was founded 1860-1910. Until 1892 the contents of latrines were still collected and driven to the country for fertilization. The rest of the sewage was lead to the harbour, causing extreme odours...

Field monitoring and evaluation of the stormwater management StormFilter\302\256 in the State of Washington

J. H. Lenhart & S. De Ridder
In 2003 the Washington State Department of Ecology adopted new criteria defining a design storm and expected BMP removal performance. Ecology also formed a Technical Review Committee (TRC) to establish a protocol for evaluating BMPs, which became known as the \342\200\234Technology Acceptance Protocol\342\200\224Ecology\342\200\235 (TAPE). To gain approval a manufacturer prepares an application including a technology description, maintenance and cost information, laboratory and field data. Based on this application the TRC gives a designation. Technologies receiving...

Potentials of stored Rainwater as an alternative water resource to meet the increasing water demand: A case study

T. Tamama, T. Kawasaki & Y.Nakayama
Detention/storage of rainwater instead of its quick removal is an effective control measure for urban drainage. As well as its peak-cut effect, multi-purpose use of stored rainwater is expected as an on-site water resource. Though Japan is not an arid area (annual average precipitation is 1,718mm/year) serious water supply shortage arises at times in some urban areas, due to the heavily concentrated population or industrial activities and the relatively small catchment area. Utilization of stored...

Integrated Simulation of the Berlin Sewage System and Evaluation of a global Real-time Control Concept

K. Schroeder, R. Mannel, E. Pawlowsky-Reusing & J. Broll
The paper presents the build-up of a model for the integrated simulation of the sewage system of Berlin, Germany, focusing on the catchment of the wastewater treatment plant Ruhleben. The Ruhleben catchment, draining 185 km\302\262 and a population of 1.38 million inhabitants is characterised by its high portion of combined sewerage. The model comprises the collection system, pump stations, pressurised mains and the wastewater treatment plant. Hydraulic and quality processes are taken into account. A...

Light Directional Elements (LDIR)

Kasper Bayer Frøhling, Mette Funding La Cour, Mohammed Jassim Ismaiil Al-Abaddi, Søren Vang Fischer, Peter Bøggild & Anders Kristensen
Using the light of the sun as the primary source for illuminating offices and houses is one of the most effective ways of saving energy. The problem, which many knows, is that on a sunny summer day, the light may be too intense to be used directly. Reading a book if the rays of the sun hits directly on the pages can be impossible, not to mention the problem of seeing what is happening on...

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