Pressure Transients in Hydraulic Pipelines,"

Equations of motion for a cylindrical tube containing a fluid are developed from a co

Pipeline network features and leak detection by cross-correlation analysis of reflected waves

This paper describes progress on a new technique to detect pipeline features and leaks using signal processing of a pressure wave measurement. Previous work (by the present authors) has shown that the analysis of pressure wave reflections in fluid pipe networks can be used to identify specific pipeline features such as open ends, closed ends, valves, junctions, and certain types of bends. It was demonstrated that by using an extension of cross-correlation analysis, the identification of features can be achieved using fewer sensors than are traditionally employed. The key to the effectiveness of the technique lies in the artificial generation of pressure waves using a solenoid valve, rather than relying upon natural sources of fluid excitation. This paper uses an enhanced signal processing technique to improve the detection of leaks. It is shown experimentally that features and leaks can be detected around a sharp bend and up to seven reflections from features/ leaks can be detected, by which time the wave has traveled over 95 m. The testing determined the position of a leak to within an accuracy of 5%, even when the location of the reflection from a leak is itself dispersed over a certain distance and, therefore, does not cause an exact reflection of the wave

A multispectral photographic experiment based on a statistical analysis of spectrometric data Final report

Multispectral photographic experiment based on statistical analysis of spectrometric data - spectral reflectance for terrain, optimum film- filter combinations, and terrain tone signature

Understanding air release through air valves

[EN] Water transients with entrapped air can originate large pressure peaks that can severely damage distribution networks. Entrapped air can have a damping or amplifying effect on these undesirable pressure peaks. Unfortunately, the complexity of the phenomenon too often makes it difficult to obtain a fully reliable prediction about when air pockets will mitigate or accentuate water transients. Furthermore, the value of some of the parameters involved in the conventional numerical models cannot be calculated or measured and need to be determined through a calibration process. With the aim of overcoming most of the aforementioned uncertainties, this paper summarizes a complete set of tests conducted at WL | Delft Hydraulics. These tests were simulated by means of a tailored numerical model that includes a set of parameters whose values were determined by means of a calibration process. The experimental setup, a large-scale facility, consisted of a single steep pipeline with an air valve installed at its top end. Air release through different air valves was tested under different conditions. © 2011 American Society of Civil Engineers.This research has been possible thanks to the European Community Programme "Access to Major Research Infrastructure" under the Fifth Framework Growth Programme (Contract No. GIRT-CT-2002-05069).Carlos Alberola, MDM.; Arregui De La Cruz, F.; Cabrera Marcet, E.; Palau, C. (2011). Understanding air release through air valves. Journal of Urban Planning and Development. 137(4):461-469. doi:10.1061/(ASCE)HY.1943-7900.0000324S461469137

The Dynamics of EBV Shedding Implicate a Central Role for Epithelial Cells in Amplifying Viral Output

To develop more detailed models of EBV persistence we have studied the dynamics of virus shedding in healthy carriers. We demonstrate that EBV shedding into saliva is continuous and rapid such that the virus level is replaced in ≤2 minutes, the average time that a normal individual swallows. Thus, the mouth is not a reservoir of virus but a conduit through which a continuous flow stream of virus passes in saliva. Consequently, virus is being shed at a much higher rate than previously thought, a level too high to be accounted for by replication in B cells in Waldeyer's ring alone. Virus shedding is relatively stable over short periods (hours-days) but varies through 3.5 to 5.5 logs over longer periods, a degree of variation that also cannot be accounted for solely by replication in B cells. This variation means, contrary to what is generally believed, that the definition of high and low shedder is not so much a function of variation between individuals but within individuals over time. The dynamics of shedding describe a process governing virus production that is occurring independently ≤3 times at any moment. This process grows exponentially and is then randomly terminated. We propose that these dynamics are best explained by a model where single B cells sporadically release virus that infects anywhere from 1 to 5 epithelial cells. This infection spreads at a constant exponential rate and is terminated randomly, resulting in infected plaques of epithelial cells ranging in size from 1 to 105 cells. At any one time there are a very small number (≤3) of plaques. We suggest that the final size of these plaques is a function of the rate of infectious spread within the lymphoepithelium which may be governed by the structural complexity of the tissue but is ultimately limited by the immune response

Yorkshire Enhanced Stop Smoking (YESS) study: a protocol for a randomised controlled trial to evaluate the effect of adding a personalised smoking cessation intervention to a lung cancer screening programme

Introduction: Integration of smoking cessation (SC) into lung cancer screening is essential to optimise clinical and cost effectiveness. The most effective way to use this ‘teachable moment’ is unclear. The Yorkshire Enhanced Stop Smoking study will measure the effectiveness of an SC service integrated within the Yorkshire Lung Screening Trial (YLST) and will test the efficacy of a personalised SC intervention, incorporating incidental findings detected on the low-dose CT scan performed as part of YLST. / Methods and analysis: Unless explicitly declined, all smokers enrolled in YLST will see an SC practitioner at baseline and receive SC support over 4 weeks comprising behavioural support, pharmacotherapy and/or a commercially available e-cigarette. Eligible smokers will be randomised (1:1 in permuted blocks of random size up to size 6) to receive either an enhanced, personalised SC support package, including CT scan images, or continued standard best practice. Anticipated recruitment is 1040 smokers (January 2019–December 2020). The primary objective is to measure 7-day point prevalent carbon monoxide (CO) validated SC after 3 months. Secondary outcomes include CO validated cessation at 4 weeks and 12 months, self-reported continuous cessation at 4 weeks, 3 months and 12 months, attempts to quit smoking and changes in psychological variables, including perceived risk of lung cancer, motivation to quit smoking tobacco, confidence and efficacy beliefs (self and response) at all follow-up points. A process evaluation will explore under which circumstances and on which groups the intervention works best, test intervention fidelity and theory test the mechanisms of intervention impact. / Ethics and dissemination: This study has been approved by the East Midlands-Derby Research Ethics Committee (18/EM/0199) and the Health Research Authority/Health and Care Research Wales. Results will be disseminated through publication in peer-reviewed scientific journals, presentation at conferences and via the YLST website. / Trial registration numbers: ISRCTN63825779, NCT03750110

Multi-agent simulation of hydraulic transient equations in pressurized systems

Computational modeling pervades virtually every industrial process. By using numerical representations of the behavior of elements that constitute a system it is possible to obtain efficient and safe designs. Moreover, system operation can be better defined by using such models, thus enabling greater reliability and control. In this paper the use of agents to solve the equations describing fast transients in water networks is investigated. As the simulation of hydraulic transients in pressurized systems is a naturally distributed problem, the authors argue that a multi-agent based system is very suitable for the solution of this complex engineering phenomenon. A hybrid solution is built by deploying agents to work with sets of equations describing hydraulic transient behavior in pipeline systems. The details necessary to assemble a complete and lubricated machine to model the complex phenomenon of hydraulic transients in pressurized systems are described. This research develops a platform that constitutes an efficient and versatile tool of great interest for water supply managers when analyzing water hammer effects in their networks.Izquierdo Sebastián, J.; Montalvo Arango, I.; Pérez García, R.; Ayala Cabrera, D. (2015). Multi-agent simulation of hydraulic transient equations in pressurized systems. Journal of Computing in Civil Engineering. 04015071:1-14. doi:10.1061/(ASCE)CP.1943-5487.0000549S1140401507

Yorkshire Enhanced Stop Smoking study (YESS): a protocol for a randomised controlled trial to evaluate the effect of adding a personalised smoking cessation intervention to a lung cancer screening programme

Introduction:Integration of smoking cessation (SC) into lung cancer screening (LCS) is essential to optimise clinical and cost effectiveness. The most effective way to use this “teachable moment” is unclear. The Yorkshire Enhanced Stop Smoking study (YESS) will measure the effectiveness of a SC service integrated within the Yorkshire Lung Screening Trial (YLST) and will test the efficacy of a personalised SC intervention, incorporating incidental findings detected on the low-dose computed tomography scan performed as part of YLST.Methods and analysis: Unless explicitly declined, all smokers enrolled in YLST will see a Smoking Cessation Practitioner (SCP) at baseline and receive smoking cessation support over 4-weeks comprising behavioural support, pharmacotherapy and/or a commercially available e-cigarette. Eligible smokers will be randomised (1:1 in permuted blocks of random size up to size 6) to receive either an enhanced, personalised smoking cessation support package, including CT scan images, or continued SBP. Anticipated recruitment is 1040 smokers (January 2019 – December 2020). The primary objective is to measure 7-day point prevalent carbon monoxide (CO) validated smoking cessation after 3-months. Secondary outcomes include CO validated cessation at 4-weeks and 12-months, self-reported continuous cessation at 4-weeks, 3-month and 12-months, attempts to quit smoking and changes in psychological variables, including perceived risk of lung cancer, motivation to quit smoking tobacco, confidence and efficacy beliefs (self and response) at all follow up points. A process evaluation will explore under which circumstances and on which groups the intervention works best, test intervention fidelity and theory test the mechanisms of intervention impact.Ethics and dissemination: This study has been approved by the East Midlands-Derby Research Ethics Committee (18/EM/0199) and the Health Research Authority/Health and Care Research Wales. Results will be disseminated through publication in peer-reviewed scientific journals, presentation at conferences and via the YLST website. Trial registration number: ISRCTN63825779; NIH ClinicalTrials.gov NCT0375011