Alternative Strategies For Optimal Water Quality Sensor Placement In Drinking Water Distribution Networks

The most commonly applied strategies for optimal water quality sensor placement in drinking water distribution systems are aimed at contamination early warning systems. These strategies aim to minimize the number of people affected in case of a deliberate contamination of drinking water in the distribution system, and provide a valuable tool. A number of factors which are usually not taken into account, including the response strategy to the identification of a contamination event, the fallibility of sensors and changes in network configuration (valve manipulation) and operation, may affect the results of these strategies. Since the quickness and effectiveness of a response is generally also a function of the location of the contamination event (both source and first detection), knowledge on the response strategy should also be part of the sensor placement optimization methodology. Hydraulic models generally play a central role in the optimization of sensor placement. The validity of their computations strongly depends upon accurate and up to date information on the network, which is often not fully available (e.g. unregistered valve status changes). Therefore, a sensor network configuration which is somewhat robust to these issues is desirable. Besides contamination early warning systems, there are several other reasons for placing water quality sensors in distribution network, including process control and monitoring, regulatory monitoring, etc. These require a different approach to optimization of the sensor network in terms of sensor locations. In this paper, we demonstrate the application of different sensor location optimization strategies in drinking water distribution networks, with aims such as minimization of the number of people affected, maximization of distribution network coverage, optimization of sensor network robustness and optimization of contamination source identification. We present and compare results of these different approaches applied to hydraulic models of a real drinking water distribution network in the Netherlands

Flow Analysis And Leak Detection With The CFPD Method In The Paris Drinking Water Distribution System

With significant drinking water loss rates \u3e10% during distribution at many drinking water utilities worldwide, the detection of new leaks, especially small and slowly growing leaks, remains an important challenge for the water sector. Time series of flow rates into isolated or completely metered distribution areas (e.g. District Metered Areas) contain signals of all existing and new leaks in that area, and also of all other processes taking place, e.g. changes in demand, operations, etc. Therefore, in principle these data can provide valuable information about new leaks, unregistered changes in valve status, etc. However, distinguishing one from the others is often difficult. The CFPD (Comparison of Flow Pattern Distributions) method is a flow time series data transformation which facilitates the identification, quantification, and interpretation of changes in the amounts of water supplied. Contrary to the often applied minimum night flow analysis, it uses all available flow data (24 hours per day, resolution of 1 measurement per hour or better) and recognizes different types of changes. In this way, it helps to distinguish e.g. new leaks from operational signals and demand changes. In the past year, it has been successfully applied at several Dutch drinking water companies. In this paper, we illustrate the application of the CFPD method by presenting selected results from CFPD analyses of flow data for 16 of 30 DMAs in the city of Paris. The findings are compared to a list of registered leaks

Predicting The Impact Of Climate Change On Pipe Failure In Drinking Water Distribution Systems.

Underground water infrastructure is designed to withstand a variability of forces during its lifetime before failure occurs. As a result of variations in loads on and deterioration of the pipe, early failures may occur. Climate change may accelerate or decelerate these processes. A statistical analysis is therefore performed to study correlations between weather parameters and pipe failure rates in the drinking water distribution systems (DWDS) of the Netherlands. The strongest correlations were found between pipe failure rates and temperature. Failure rates in asbestos cement (AC) and small diameter steel pipes increase during warm periods, which often also show higher water consumptions . For cast iron (CI) pipes, failure rates increase at low temperatures. Drought parameters have a smaller effect on pipe failure rates than temperature, but still an increase in pipe failure rates was observed during dry periods for AC and small diameter steel pipes. No effect of weather conditions on pipe failure is observed for PVC and PE pipes. Using the statistical relations between pipe failure frequencies and weather conditions, a methodology is proposed to assess the effect of climate change on the integrity of DWDSs. This results in an insightful representation of the vulnerability of existing and future DWDSs towards climate change. This analysis can be conducted for any DWDS, for which historical failure registrations and weather parameters are available. The proposed methodology can therefore assist in the construction and maintenance planning of DWDSs. The methodology has applied to the combined Dutch drinking water distribution networks. The results show how failure rates in networks with a significant proportion of AC will increase as a result of expected climate change in the Netherlands, whereas failure rates in networks with high proportions of PVC and CI are expected to decrease slightly

Evolving dynamical regimes during secular cooling of terrestrial planets : insights and inferences from numerical models

Although plate tectonics is the present-day mode of geodynamics on Earth, it is not so on Mars and Venus, and probably also not during the early history of the Earth. In this thesis, the conditions under which plate tectonics may operate on terrestrial planets are investigated. Numerical model studies, presented in the thesis, show show that plate tectonics on Earth may be opposed by lithosphere buoyancy at potential mantle temperatures above about 1500C. For Venus, this value is about 1450C, and for Mars, it is even lower (1300-1400C). Parametric models of plate tectonics and massive flood volcanism are used to determine the cooling characteristics of these mechanisms. Numerical mantle convection models including differentiation by partial melting are applied to investigate an alternative type of dynamics which may have operated under conditions too hot for plate tectonics. The results show a suite of processes which produce and recycle oceanic crust and cool the planetary mantle: 1) small scale delamination of the lower crust; 2) large scale resurfacing events in which sections of crust of 1000 km long may sink into the mantle in about 2 million years, being replaced by newly produced crust; 3) intrusion of hot and fertile material from the lower mantle into the upper mantle, causing diapirs which are significantly hotter (excess temperature of 250K) than those predicted from boundary layer theory for a hot mantle and which produce large volumes of basaltic melt. In order to link model results to observations, the conditions of melting of basaltic crust in the model settings described above are compared to the conditions of formation of an important consituent of Archean crations, TTG (Tonalite-Trondhjemite-Granodiorite) plutons, which have been formed by partial melting of meta-basalt under amphibolite conditions. The results show that specifically the resurfacing events create conditions favorable for the production of TTG rocks, and the rock associations produced in the models resemble those in Archean granite-greenstone terrains. Therefore, the resurfacing mechanism may have contributed to the formation of proto-continents. The long-term stability of Archean cratons has been ascribed to the presence of thick roots underneath these regions, and addition of depleted mantle rock by mantle upwellings undergoing partial melting has been shown to contribute to the formation of these roots. In model experiments presented in this thesis, the effect of different types of rheology (grainsize dependent diffusion creep, diffusion creep + dislocation creep, diffusion creep + dislocation creep + dehydration by partial melting) on the development of these diapirs is studied. The model results show a self-regulating mechanism to be operative, which causes the dynamics to be relatively insensitive to grainsize. Tentative planetary histories are constructed from the results obtained in the production of this thesis: After cooling down from the magma ocean regime, episodic resurfacing possibly further cooled the planet down to the conditions favorable for plate tectonics, which then took over. This transition was probably gradual. It is speculated that Venus is still in the stage of episodic resurfacing. Mars was probably relatively inactive from its very early history on

Evaluation of handheld X-ray fluorescence spectroscopy results of Roman copper alloy brooches by using archaeological typology

As part of the Late Roman research project in Belgium and the Netherlands, 187 Roman copper alloy brooches were analyzed by means of handheld X-ray fluorescence (hXRF) spectroscopy in order to explore the relationship between composition, production organization and change over time. The selected brooch type is called ‘the crossbow brooch’, which is an artifact that is closely associated with the Late Roman elite, frequently occurring in many portraits on mosaics, sculptures and fresco’s from the 4th to the 6th century. The biography of the crossbow brooch, however, starts in the 3rd century as a simple military object and develops into one of the most significant symbols of Roman state authority in the 5th and 6th century. The hXRF spectrometer provided a non-destructive, mobile, quick and inexpensive way of analyzing these brooches that were part of valued museum and archaeological collections. The samples were selected to cover the entire chronological, geographical and stylistic variation of these brooches in the study area. Each object was measured in three to five locations to compensate the heterogeneity of the copper alloy and the geometry of the object. The compositional results revealed a continuous variation that crosses copper alloy boundaries with no evident groups or trends, as is often the case for archaeological data sets. To move beyond a black box approach that provides little insights, the typological information was added to interpret the compositional data. An archaeological typology is constructed based on observed variations that represent expressions of choices made by craftsmen and workshops. In other words, typology contains information that can help explain compositional variation caused by different manufacturing techniques or production centers, changes in consumer demands, as well as factor in aspects of chronology and regionality. Consequently, the division of the compositional data in the six types of crossbow brooches allowed to distinguish patterns that indicated changes in production organization related to social context. The combination of typology and compositional data allowed to characterize the different phases in the crossbow brooches’ life history, which in its turn contributed to the larger narrative of the rise to power of the military elite in the Late Roman period

Soft Sensing The Potential Amount Of Calcium Carbonate Precipitate In Drinking Water Distribution Infrastructure And Warm Water Household Appliances

A soft sensor is developed to predict the potential amount of precipitation of calcium carbonate (CCPP) in warm water household devices and scaling or corrosive behavior in water distribution networks. With the aid of a water supply network model, it is shown that the soft sensor is able to predict CCPP levels at pre-specified downstream nodes using only measurements at a limited set of upstream nodes. Furthermore, the soft sensor consists of a data assimilation algorithm to provide for best estimates of the CCPP and confidence intervals

Differential regulation of Krüppel-like factor family transcription factor expression in neonatal rat cardiac myocytes: effects of endothelin-1, oxidative stress and cytokines

Krüppel-like transcription factors (Klfs) modulate fundamental cell processes. Cardiac myocytes are terminally-differentiated, but hypertrophy in response to stimuli such as endothelin-1. H2O2 or cytokines promote myocyte apoptosis. Microarray studies of neonatal rat myocytes identified several Klfs as endothelin-1-responsive genes. We used quantitative PCR for further analysis of Klf expression in neonatal rat myocytes. In response to endothelin-1, Klf2 mRNA expression was rapidly increased ( approximately 9-fold; 15-30 min) with later increases in expression of Klf4 and Klf6 ( approximately 5-fold; 30-60 min). All were regulated as immediate early genes (cycloheximide did not inhibit the increases in expression). Klf5 expression was increased at 1-2 h ( approximately 13-fold) as a second phase response (cycloheximide inhibited the increase). These increases were transient and attenuated by U0126. H2O2 increased expression of Klf2, Klf4 and Klf6, but interleukin-1beta or tumor necrosis factor alpha downregulated Klf2 expression with no effect on Klf4 or Klf6. Of the Klfs which repress transcription, endothelin-1 rapidly downregulated expression of Klf3, Klf11 and Klf15. The dynamic regulation of expression of multiple Klf family members in cardiac myocytes suggests that, as a family, they are actively involved in regulating phenotypic responses (hypertrophy and apoptosis) to extracellular stimuli

Cross Adaptation - Heat and Cold Adaptation to Improve Physiological and Cellular Responses to Hypoxia

To prepare for extremes of heat, cold or low partial pressures of O2, humans can undertake a period of acclimation or acclimatization to induce environment specific adaptations e.g. heat acclimation (HA), cold acclimation (CA), or altitude training. Whilst these strategies are effective, they are not always feasible, due to logistical impracticalities. Cross adaptation is a term used to describe the phenomenon whereby alternative environmental interventions e.g. HA, or CA, may be a beneficial alternative to altitude interventions, providing physiological stress and inducing adaptations observable at altitude. HA can attenuate physiological strain at rest and during moderate intensity exercise at altitude via adaptations allied to improved oxygen delivery to metabolically active tissue, likely following increases in plasma volume and reductions in body temperature. CA appears to improve physiological responses to altitude by attenuating the autonomic response to altitude. While no cross acclimation-derived exercise performance/capacity data have been measured following CA, post-HA improvements in performance underpinned by aerobic metabolism, and therefore dependent on oxygen delivery at altitude, are likely. At a cellular level, heat shock protein responses to altitude are attenuated by prior HA suggesting that an attenuation of the cellular stress response and therefore a reduced disruption to homeostasis at altitude has occurred. This process is known as cross tolerance. The effects of CA on markers of cross tolerance is an area requiring further investigation. Because much of the evidence relating to cross adaptation to altitude has examined the benefits at moderate to high altitudes, future research examining responses at lower altitudes should be conducted given that these environments are more frequently visited by athletes and workers. Mechanistic work to identify the specific physiological and cellular pathways responsible for cross adaptation between heat and altitude, and between cold and altitude, is warranted, as is exploration of benefits across different populations and physical activity profiles