185 research outputs found
A Study of the Concurrent Validity between the Boxall Profile and the Strengths and Difficulties Questionnaire
No full textThe aim of the study is to establish the level of concurrent validity between the Boxall Profile, a diagnostic instrument used by teachers and teaching assistants in nurture groups, and the Strengths and Difficulties Questionnaire, a widely used screening instrument in the fields of education, mental health and social work. 202 children and adolescents attending nurture groups in England, aged 3-14 years, participated in the study. . These consisted of142 boys and 60 girls and came from 25 schools in 8 LEAs. School staff completed the Boxall Profile and Strengths and Difficulties Questionnaire for all pupils. . The results show a high degree of concordance between the two instruments, with both measures appearing to identify similar behavioural characteristics in the same children. Scores in specific domains of the Boxall Profile are shown to predict performance on particular sub-scales of the Strengths and Difficulties Questionnaire. These preliminary findings support the validity claims of the Boxall Profile, indicating that it is a reliable tool for both diagnostic and research purposes
Hydraulic reliability analysis using a pressure-driven network simulation model
No full textThe hydraulic reliability of a water distribution network is usually referred to as the inability to supply required water demands due to variations of some hydraulic parameters, such as pipe hydraulic resistance and/or required demands. This undermines the application of conventional deterministic approach to modeling water distribution networks when used for the network reliability analysis, calling for the assumption of uncertainty scenarios for nodal demands and/or pipe roughness. The paper deals with a stochastic approach for simulation of nodal demands uncertainty and the presence of leakages. The reliability analysis will be performed via demand-driven and pressure-driven hydraulic simulation using the Apulian network, whereas pipe diameters have been sized by means of a least cost design procedure. The analysis highlights the difference in hydraulic reliability assessment according to the use of hydraulic simulation model, showing that pressure-driven approach is mandatory for an accurate network hydraulic reliability investigation
Assessment of the head dependent gradient method with reference to PRAAWDS
No full textA collection of articles by leading international experts on modeling and control of potable water distribution and sewerage collection systems, focusing on advances in sensors, instrumentation and communications technologies; assessment of sensor reliability, accuracy and fitness; data management including SCADA and GIS; systems modelling, optimisation and decision support; real time monitoring, modelling control and associated uncertainties; water quality, water and wastewater treatment modeling; demand forecasting, leakage and energy management; asset management and performance modeling; sustainable urban water management including flooding issues; security, reliability and resilience of water systems; likely impacts of climate change; Water scarcity and intermittent supply. Intended for water researchers in industry and academi
Occurrence of transients in water distribution networks
No full textThe common existence of pressure transients in operational water distribution systems (WDS) requires their characterisation and assessment of their impact. This paper performs such characterisation by evidencing the occurrence and the differences in pressure transient behaviour in complex WDS. Ten samples of continuously recorded high resolution pressures from diverse networks and sources were analysed. The presented pressure traces show regular and occasional pressure transient waves in various complex networks. Histogram analysis of the rate of change of head provides some insight into transient behaviour in these sites. Although there was no distinct correlation between network characteristics (ie. length, diameter, age) and transient behaviour, network complexity was observed to change the transient characteristics. Transient characteristics were observed to be strongly influenced by likely sources, in particular commercial customers. The data highlights the need to understand, quantify and characterise transients and hence link to possible impacts, such as structural or water quality failures
Multiobjective optimization and multicriteria decision making for water networks
No full textA collection of articles by leading international experts on modeling and control of potable water distribution and sewerage collection systems, focusing on advances in sensors, instrumentation and communications technologies; assessment of sensor reliability, accuracy and fitness; data management including SCADA and GIS; systems modelling, optimisation and decision support; real time monitoring, modelling control and associated uncertainties; water quality, water and wastewater treatment modeling; demand forecasting, leakage and energy management; asset management and performance modeling; sustainable urban water management including flooding issues; security, reliability and resilience of water systems; likely impacts of climate change; Water scarcity and intermittent supply. Intended for water researchers in industry and academi
Understanding and managing large sensor networks
No full textThe water supply industry is trialing a range of sensor network designs for monitoring distributed infrastructure. The paper investigates the performance of such a sensor system deployed to monitor a water distribution network. The study reveals up to one fifth of the data intended to be collected either to be missing or erroneous. Findings reinforce the importance of in-depth design consideration of all aspects of large scale sensor systems, and the necessity for expertise on every detail of the system, or access to a rule set which embeds this knowledge allowing non-specialists to make near optimal choices. First steps towards defining such a rule set is presented here with supporting evidence
Pressure driven analysis of water distribution networks based on the knowledge of the actual connection to properties
No full textPressure-driven simulation of water distribution systems constitutes an approach which can realistically reproduce the behavior of a network in terms of nodal discharges as function of the actual nodal pressures. Moreover, this approach allows also for the estimation of water losses, based on a leakage model at a pipe scale. Pressure-driven analysis, aswell as demand-driven one, is commonly undertaken under the assumption of lumping flows into the end nodes of each pipe. This kind of hypothesis is due to simplification of the topology related to computational reasons as well as to the lack of information about each single connection of pipes to properties. However, this assumption can return a poor description of pipes energy balance conservation equation and thus a wrong approximation that could generate large head loss errors. The advent of information technology and Geographical Information Systems in water industry led to the availability of the actual number and position of the connections to the properties along the mains of the water distribution networks. This paper shows the extension of a pressure-driven analysis algorithm to the scenario where pipes connections and consumptions are known. Furthermore, as shown in a real case study, the proposed pressure-driven algorithm allows a more accurate analysis of background water losse
Assessing the exposure risk and impacts of pharmaceuticals in the environment on individuals and ecosystems
No full textCopyright @ 2013 The authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/, which permits unrestricted use, provided the original author and source are credited.The use of human and veterinary pharmaceuticals is increasing. Over the past decade, there has been a proliferation of research into potential environmental impacts of pharmaceuticals in the environment. A Royal Society-supported seminar brought together experts from diverse scientific fields to discuss the risks posed by pharmaceuticals to wildlife. Recent analytical advances have revealed that pharmaceuticals are entering habitats via water, sewage, manure and animal carcases, and dispersing through food chains. Pharmaceuticals are designed to alter physiology at low doses and so can be particularly potent contaminants. The near extinction of Asian vultures following exposure to diclofenac is the key example where exposure to a pharmaceutical caused a population-level impact on non-target wildlife. However, more subtle changes to behaviour and physiology are rarely studied and poorly understood. Grand challenges for the future include developing more realistic exposure assessments for wildlife, assessing the impacts of mixtures of pharmaceuticals in combination with other environmental stressors and estimating the risks from pharmaceutical manufacturing and usage in developing countries. We concluded that an integration of diverse approaches is required to predict 'unexpected' risks; specifically, ecologically relevant, often long-term and non-lethal, consequences of pharmaceuticals in the environment for wildlife and ecosystems
Decision-Making Tools to Manage the Microbiology of Drinking Water Distribution Systems
No full textThis paper uses a two-fold multi-criteria decision-making (MCDM) approach applied for the first time to the field of microbial management of drinking water distribution systems (DWDS). Specifically, the decision-making trial and evaluation laboratory (DEMATEL) was applied removing the need for reliance on expert judgement, and analysed interdependencies among water quality parameters and microbiological characteristics of DWDS composed of different pipe materials. In addition, the fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) ranked the most common bacteria identified during trials in a DWDS according to their relative abundance while managing vagueness affecting the measurements. The novel integrated approach presented and proven here for an initial real world data set provides new insights in the interdependence of environmental conditions and microbial populations. Specifically, the application shows as the bacteria having associated the most significant microbial impact may not be the most abundant. This offers the potential for integrated management strategies to promote favourable microbial conditions to help safeguard drinking water quality
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