276 research outputs found
A statistical approach to guide the management of the anterior part of the sewer system
No full textThe anterior part of the sewer system consists of a system of gully pots and lateral (house) connections that drain to main sewers. The total length of lateral house connections can be similar to the total length of the sewers they drain to. In addition, there are 7 million gully pots with corresponding lateral connections in the Netherlands alone. Considering the potential consequences of a lateral house connection blockage, proper functioning of these system components is essential. Analysis of literature on main sewer infrastructure strongly related to lateral (house) connections indicate these components to be more susceptible to shared failure mechanisms. Both incorrect use by citizens and the structural condition seem to influence the blockage propensity. Furthermore, recent research has revealed gully pot blockages to make larger contributions to flooding in public spaces than intense storm events and main sewer blockages. Gully pots are equipped with a sand trap to prevent solids from being transported to the downstream water infrastructure. The continuous trapping of solids may eventually impair the hydraulic performance. Lack of knowledge on the condition of the anterior part of a sewer system has led to the prevalence of reactive strategies, where activities are undertaken after the consequences of an operational failure becomes apparent. Next to being more costly, these strategies expose citizens to the consequences of a failure such as tangible damages and health risks. Alternatively, proactive strategies are characterised by activities that are undertaken before a failure occurs. Preserving the functionality of lateral (house) connections and gully pots, given the available resources, calls for knowledge on the effectiveness of proactive strategies and information on blockage prone components to balance proactive and reactive activities. To this end, the general objective of this thesis is to provide a methodology that supports the optimisation of management strategies for the anterior part of the sewer system
SARS-CoV-2 Seroprevalence Studies in Pets, Spain
No full textAuthor contributions: conceptualization: S.B.-A., L.D., J.M.S.-V.; data curation: S.B.-A., L.S.-M., J.A.B.; formal analysis: S.B.-A., L.S.-M., J.A.B.; funding acquisition: J.M.S.-V., L.D.; laboratory analyses: S.B.-A., L.S.-M.; methodology: S.B.-A., L.S.-M., J.A.B., J.M.S.-V.; project administration: J.M.S.-V.; resources: L.D., J.M.S.-V.; software: S.B.-A., L.S.-M., J.A.B.; supervision: L.D., J.M.S.-V.; validation: S.B.-A., L.S.-M., J.A.B., J.M.S.-V.; visualization: S.B.-A., L.S.-M., J.A.B.; original draft preparation: S.B.-A., L.S.-M., J.A.B.; manuscript review and editing: S.B.-A., L.S.-M., J.A.B., L.D., J.M.S.-V.SARS-CoV-2 can infect domestic animals such as cats and dogs. The zoonotic origin of the disease requires surveillance on animals. Seroprevalence studies are useful tools for detecting previous exposure because the short period of virus shedding in animals makes detection of the virus difficult. We report on an extensive serosurvey on pets in Spain that covered 23 months. We included animals with exposure to SARS-CoV-2-infected persons, random animals, and stray animals in the study. We also evaluated epidemiologic variables such as human accumulated incidence and spatial location. We detected neutralizing antibodies in 3.59% of animals and showed a correlation between COVID-19 incidence in humans and positivity to antibody detection in pets. This study shows that more pets were infected with SARS-CoV-2 than in previous reports based on molecular research, and the findings highlight the need to establish preventive measures to avoid reverse zoonosis events.Instituto de Salud Carlos IIIEuropean CommissionComunidad de MadridDepto. de Sanidad AnimalCentro de Vigilancia Sanitaria Veterinaria (VISAVET)TRUEpu
Analysing spatial patterns in lateral house connection blockages to support management strategies
No full textThe performance of lateral house connections has a direct impact on sewer serviceability. Despite the potential consequences of a blockage, these components are generally maintained with a reactive approach. As inspection data on the condition of lateral house connections are scarce, this study adopts a statistical procedure to support proactive strategies by analysing spatial blockage patterns to identify system parts with higher blockage incidences. First, a Monte Carlo simulation test provides insight into whether the spatial variation of the blockage likelihood is significant. This justifies the identification of explanatory factors by means of a bootstrapped generalised additive model. Application of the procedure to two databases containing 10 years of lateral house connection blockage data, revealed factors such as building age, sewer system type and ground settlement rate to explain spatial differences in the blockage likelihood. Furthermore, a likelihood ratio test demonstrated that the addition of a spatial smoother improved model performance. This smoother was able to account for additional spatial variation caused by explaining factors for which no data were available. The procedure provides key information for inspection and rehabilitation strategies by taking into account the model performance in assessing the trade-off between costs and benefits in terms of serviceability.Sanitary Engineerin
Global Food Security Governance: Civil Society Engagement in the Reformed Committee on World Food Security
No full textIn 2007/8 world food prices spiked and global economic crisis set in, leaving hundreds of millions of people unable to access adequate food. The international reaction was swift. In a bid for leadership, the 123 member countries of the United Nations’ Committee on World Food Security (CFS) adopted a series of reforms with the aim of becoming the foremost international, inclusive and intergovernmental platform for food security. Central to the reform was the inclusion of participants (including civil society and the private sector) across all activities of the Committee. Drawing on data collected from policy documents, interviews and participant observation, this book examines the re-organization and functioning of a UN Committee that is coming to be known as a best practice in global governance. Framed by key challenges that plague global governance, the impact and implication of increased civil society engagement are examined by tracing policy negotiations within the CFS, in particular, policy roundtables on smallholder sensitive investment and food price volatility and negotiations on the Voluntary Guidelines on the Responsible Governance of Tenure of Land, Fisheries and Forests in the Context of National Food Security, and the Global Strategic Framework for Food Security and Nutrition. The author shows that through their participation in the Committee, civil society actors are influencing policy outcomes. Yet analysis also reveals that the CFS is being undermined by other actors seeking to gain and maintain influence at the global level. By way of this analysis, this book provides empirically-informed insights into increased participation in global governance processes
The impact of lateral house connections on the serviceability of sewer systems
No full textIt remains unknown how lateral house connections affect the performance of the sewer system, since the assessment of serviceability is mainly based on the state of the main sewer system. Further insight into the contribution of lateral house connections to the overall level of service provided can aid to target investments to parts of the system where it is most effective. To this end, techniques from the reliability theory were applied to a commercial sewer maintenance database to quantify the impact of lateral house connections on the serviceability of sewer systems. Analysis of the data showed that the failures follow a Poisson distribution. A comparison of the derived failure rate with values obtained from a different study revealed that the blockage rate of lateral house connections is an order of magnitude greater than the failure rate of the dominant mechanism of main sewer systems, thereby making the impact of lateral house connections on the serviceability of sewer systems substantial.Water ManagementCivil Engineering and Geoscience
A gaming approach to networked infrastructure management
No full textOperational decision-making processes for networked infrastructure management often occur as a multi-actor planning problem, implying these are based on negotiations between different stakeholders in addition to available system quality information. As such, does more accurate data about actual structural condition lead to other or better decision-making? A serious game is introduced, Maintenance in Motion, aiming at investigating the influence of information quality on rehabilitation decisions, for single- and multi-actor decision-making. Players manage drinking water, gas, sewer and street infrastructures. They are to balance their individual goal, cost-effectiveness, with their team utility, increasing overall infrastructure quality to minimise failure while minimising overall public costs. The game design, calibration and solution space are presented.Sanitary EngineeringEnergie and Industri
Statistical modelling of Fat, Oil and Grease (FOG) deposits in wastewater pump sumps
No full textThe accumulation of FOG (Fat, Oil and Grease) deposits in sewer pumping stations results in an increase in maintenance costs, malfunctioning of pumps and, a potential increase of wastewater spills in receiving open water bodies. It is thought that a variety of parameters (e.g. geometry of the pump sump, pump operation, socioeconomic parameters of the catchment) influences the built-up of FOG. Based on a database containing data of 126 pumping stations located in five Dutch municipalities a statistical model was built. It is shown that 3 parameters are most significant in explaining the occurrence of FOG deposits: mean income of the population in a catchment, the amount of energy (kinetic and potential) per m3 per day and the density of restaurants, bars and hotels in a catchment. Further it is shown that there are significant differences between municipalities that can be traced back to the local ‘design paradigm’. For example, in Amsterdam, the design philosophy of discharging in the pump sump under the water surface (and hence maintaining a low level of turbulence in the pump sump) results in an increase of the probability of the formation of FOG.Sanitary Engineerin
ASDE and multilateration mode-S data fusion for location and identification on airport surface
No full textMineral phase analysis of deep-sea hydrothermal particulates by a Raman spectroscopy expert algorithm : toward autonomous in situ experimentation and exploration
No full textAuthor Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 10 (2009): Q05T05, doi:10.1029/2008GC002314.This paper demonstrates that a Raman spectroscopy, point-counting technique can be used for phase analysis of minerals commonly found in deep-sea hydrothermal plumes, even for minerals with similar chemical compositions. It also presents our robust autonomous identification algorithm and spectral database, both of which were developed specifically for deep-sea hydrothermal studies. The Raman spectroscopy expert algorithm was developed and tested against multicomponent mixtures of minerals relevant to the deep-sea hydrothermal environment. It is intended for autonomous classification where many spectra must be examined with little or no human involvement to increase analytic precision, accuracy, and data volume or to enable in situ measurements and experimentation.Support for J.A.B. was provided through a RIDGE
2000 Postdoctoral Fellowship (NSF OCE-0550331)
Identifying critical elements in sewer networks using graph-theory
No full textUnderground water infrastructure is essential for life in cities. The aging of these infrastructures requires maintenance strategies to maintain a minimum service level. Not all elements are equally important for the functioning of the infrastructure as a whole. Identifying the most critical elements in a network is crucial for formulating asset management strategies. The graph theory is presented as a means to identify the most critical elements in a network with respect to malfunctioning of the system as a whole. As opposed to conventional methods, the proposed method does not rely on iterative hydraulic calculations; instead, the structure of the network is taken as a starting point. In contrast to methods applied in practise, the results are independent on the chosen test-load. Because of the limited calculation effort, the method allows the analysis of large networks that are now, for practical reasons, beyond the scope of methods applied so-far.Sanitary EngineeringMathematical Physic
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