Principles of the full-scale aerobic granular sludge process

A General Model for Biofilm-Driven Microbial Electrosynthesis of Carboxylates From CO₂

Up to now, computational modeling of microbial electrosynthesis (MES) has been underexplored, but is necessary to achieve breakthrough understanding of the process-limiting steps. Here, a general framework for modeling microbial kinetics in a MES reactor is presented. A thermodynamic approach is used to link microbial metabolism to the...

Time-frequency analysis of ship wave patterns in shallow water: modelling and experiments

Association with pathogenic bacteria affects life-history traits and population growth in Caenorhabditis elegans

Determining the relationship between individual life-history traits and population dynamics is an essential step to understand and predict natural selection. Model organisms that can be conveniently studied experimentally at both levels are invaluable to test the rich body of theoretical literature in this area. The nematode Caenorhabditis...

Using System Dynamics to Explore the Water Supply and Demand Dilemmas of a Small South African Municipality

This paper explores the challenges faced by small municipalities in providing water services in a developing-world context of increasing urban demand. The paper uses a case study of the Sundays River Valley Municipality (SRVM) in South Africa. The municipality faces multiple dilemmas in reconciling its available water supply with growing demand...

Ein Algebrisches Turbulenzmodel für Ästuare

The density distribution within a fluid is of great importance for flow and transport phenomena in geophysical computational fluid dynamics. All turbulent exchange processes are influenced by buoyancy effects and must be adequately considered in numerical models. Parameterizations of the vertical eddy viscosity and eddy diffusivity are presented...

Flow measurements in a curved rectangular channel

This report describes an extensive experiment on steady turbulent flow in a rather sharply curved U-shaped flume with a shallow rectangular cross-section, under almost the same conditions as earlier, less extensive measurements in the same flume. The experiment was carried out as a part of a research project aiming at a mathematical model of the...

Steady turbulent flow in curved rectangular channels

After the study of fully developed and developing steady laminar flow in curved channels of shallow rectangular wet cross-section (see earlier reports in this series), steady turbulent flow in such channels is investigated as a next step towards a mathematical model of the flow in shallow river bends. A mathematical model is developed for this...

Kuantan River, Malaysia: Prediction of salinity intrusion

A mathematical model was used to simulate the long-term movements of the high water slack longitudinal salinity profile in the estuary of the Sg Kuantan, Malaysia. The proven model was then used to predict the effects on salinity of increased abstractions from the estuary under various drought conditions. The predicted longitudinal profiles were...

Fully developed laminar flow in curved ducts

A mathematical model of steady, fully developed laminar flow in curved ducts is developed and used to derive a simplified computation method to be applied in another mathematical model predicting the flow in river bends. The laminar flow model is verified by comparing its results with analytical, numerical and experimental results reported in...

Comparison of some methods to determine the delays of landing aircraft with respect to runway capacity

The capacity of runways in use for landing aircraft may become the chief bottleneck of the capacity of airports. This runway capacity may result in long queues of aircraft waiting for landing, which in its turn results in unacceptable delays. Two analytic methods to determine these delays are described and the results are compared. The two...

Mathematical Model to Predict the Behavior of Deep-Draft Vessels in Restricted Waterways

Presently deep-draft navigation channel analysis, design and review is based on empirically derived ratios of the design vessel's dimensions. Because of radical changes in vessel operation purposes and characteristics, these ratios can no longer be safely or economically applied. The mathematical model and related theory described in this...

Performance and workload analysis of in-flight helicopter missions

The study described in this report was aimed at assessing the potentials of the optimal control model structure to predict the important characteristics of realistic operational helicopter missions. The theoretical and experimental results indicate that the optimal control model succesfully predicts the best attainable (rather than the average)...

One-dimensional analysis of salinity intrusion in estuaries

This report describes a mathematical model that was developed to predict salinity intrusion in estuaries as it is affected by control and abstraction of fresh water. The need for such a model, particularly for estuaries in tropical areas with large variations in fresh water flow, capable of giving satisfactory predictions of salinity movement...

Experiences with mathematical models used for water quality and quantity problems

The use of models for solving water quality and quantity problems is not restricted to mathematical modeIs, as other types also have their possibilities and drawbacks. Mathematical methods, however, have certain properties which make them particularly suitable for water management studies. The examples of mathematical models dealt with in this...