387 research outputs found
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
A laboratory study on cold-mix, cold-lay emulsion mixtures
This paper describes laboratory experiments and presents
results for the performances of cold-mix, cold-lay
emulsion mixtures. The main objective of the experiments
was to evaluate and improve the properties of the cold
mixtures. The mixture properties evaluated were:
volumetric properties, indirect tensile stiffness modulus
(ITSM), repeated load axial creep and fatigue. These
properties were compared with conventional hot asphalt
mixtures not containing any waste/recycled materials. To
optimise the performances of the mixtures, a target of
ITSM value of 2000 MPa was selected. At full curing
conditions, the stiffness of the cold mixes was found to be
very similar to that of hot mixtures of the same
penetration grade base bitumen (100 pen). Test results
also show that the addition of 1–2% cement significantly
improved the mechanical performance of the mixes and
significantly accelerated their strength gain. The fatigue
behaviour of the cold mixes that incorporated cement was
comparable with that of the hot mixtures
Managed Aquifer Recharge as a Tool to Enhance Sustainable Groundwater Management in California
A growing population and an increased demand for water resources have resulted in a global trend of groundwater depletion. Arid and semi-arid climates are particularly susceptible, often relying on groundwater to support large population centers or irrigated agriculture in the absence of sufficient surface water resources. In an effort to increase the security of groundwater resources, managed aquifer recharge (MAR) programs have been developed and implemented globally. MAR is the approach of intentionally harvesting and infiltrating water to recharge depleted aquifer storage. California is a prime example of this growing problem, with three cities that have over a million residents and an agricultural industry that was valued at 47 billion dollars in 2015. The present-day groundwater overdraft of over 100 km3 (since 1962) indicates a clear disparity between surface water supply and water demand within the state. In the face of groundwater overdraft and the anticipated effects of climate change, many new MAR projects are being constructed or investigated throughout California, adding to those that have existed for decades. Some common MAR types utilized in California include injection wells, infiltration basins (also known as spreading basins, percolation basins, or recharge basins), and low-impact development. An emerging MAR type that is actively being investigated is the winter flooding of agricultural fields using existing irrigation infrastructure and excess surface water resources, known as agricultural MAR. California therefore provides an excellent case study to look at the historical use and performance of MAR, ongoing and emerging challenges, novel MAR applications, and the potential for expansion of MAR. Effective MAR projects are an essential tool for increasing groundwater security, both in California and on a global scale. This chapter aims to provide an overview of the most common MAR types and applications within the State of California and neighboring semi-arid regions
Evidence for Neutrino Oscillations from Muon Decay at Rest
A search for nu_bar_mu to nu_bar_e oscillations has been conducted at the Los
Alamos Meson Physics Facility using nu_bar_mu from mu+ decay at rest. The
nu_bar_e are detected via the reaction (nu_bar_e,p) -> (e+,n), correlated with
the 2.2 MeV gamma from (n,p) -> (d,gamma). The use of tight cuts to identify e+
events with correlated gamma rays yields 22 events with e+ energy between 36
and 60 MeV and only 4.6 (+/- 0.6) background events. The probability that this
excess is due entirely to a statistical fluctuation is 4.1E-08. A chi^2 fit to
the entire e+ sample results in a total excess of 51.8 (+18.7) (-16.9) (+/-
8.0) events with e+ energy between 20 and 60 MeV. If attributed to nu_bar_mu ->
nu_bar_e oscillations, this corresponds to an oscillation probability (averaged
over the experimental energy and spatial acceptance) of 0.0031 (+0.0011)
(-0.0010) (+/- 0.0005).Comment: 57 pages, 34 figures, revtex, additional information available at
http://nu1.lampf.lanl.gov/~lsnd
Framework, principles and recommendations for utilising participatory methodologies in the co-creation and evaluation of public health interventions
Background:
Due to the chronic disease burden on society, there is a need for preventive public health interventions to stimulate society towards a healthier lifestyle. To deal with the complex variability between individual lifestyles and settings, collaborating with end-users to develop interventions tailored to their unique circumstances has been suggested as a potential way to improve effectiveness and adherence. Co-creation of public health interventions using participatory methodologies has shown promise but lacks a framework to make this process systematic. The aim of this paper was to identify and set key principles and recommendations for systematically applying participatory methodologies to co-create and evaluate public health interventions.
Methods:
These principles and recommendations were derived using an iterative reflection process, combining key learning from published literature in addition to critical reflection on three case studies conducted by research groups in three European institutions, all of whom have expertise in co-creating public health interventions using different participatory methodologies.
Results:
Key principles and recommendations for using participatory methodologies in public health intervention co-creation are presented for the stages of: Planning (framing the aim of the study and identifying the appropriate sampling strategy); Conducting (defining the procedure, in addition to manifesting ownership); Evaluating (the process and the effectiveness) and Reporting (providing guidelines to report the findings). Three scaling models are proposed to demonstrate how to scale locally developed interventions to a population level.
Conclusions:
These recommendations aim to facilitate public health intervention co-creation and evaluation utilising participatory methodologies by ensuring the process is systematic and reproducible
An introductory view on archaeoastronomy
Archaeoastronomy is still a marginalised topic in academia and is described by the Sophia Centre, the only UK institution offering a broader MA containing this field, as ‘the study of the incorporation of celestial orientation, alignments or symbolism in human monuments and architecture’. By many it is associated with investigating prehistoric monuments such as Stonehenge and combining astronomy and archaeology. The following will show that archaeoastronomy is far more than just an interdisciplinary field linking archaeology and astronomy. It merges aspects of anthropology, ethno-astronomy and even educational research, and is possibly better described as cultural astronomy. In the past decades it has stepped away from its quite speculative beginnings that have led to its complete rejection by the archaeology community. Overcoming these challenges it embraced full heartedly solid scientific and statistical methodology and achieved more credibility. However, in recent times the humanistic influences of a cultural context motivate a new generation of archaeoastronomers that are modernising this subject; and humanists might find it better described as post-modern archaeoastronomy embracing the pluralism of today’s academic approach to landscape and ancient people
Evidence for nu_mu -> nu_e Neutrino Oscillations from LSND
A search for nu_mu -> nu_e oscillations has been conducted with the LSND
apparatus at the Los Alamos Meson Physics Facility. Using nu_mu from pi^+ decay
in flight, the nu_e appearance is detected via the charged-current reaction
C(nu_e,e^-)X. Two independent analyses observe a total of 40 beam-on
high-energy electron events (60 < E_e < 200 MeV) consistent with the above
signature. This number is significantly above the 21.9 +- 2.1 events expected
from the nu_e contamination in the beam and the beam-off background. If
interpreted as an oscillation signal, the observed oscillation probability of
(2.6 +- 1.0 +- 0.5) x 10^{-3} is consistent with the previously reported
nu_mu_bar -> nu_e_bar oscillation evidence from LSND.Comment: 10 pages (LaTeX), 3 figures (PostScript), submitted to Phys.Rev.Lett.
Additional information at http://nu1.lampf.lanl.gov/~lsn
Internet of Things in Water Management and Treatment
The goal of the water security IoT chapter is to present a comprehensive and integrated IoT based approach to environmental quality and monitoring by generating new knowledge and innovative approaches that focus on sustainable resource management. Mainly, this chapter focuses on IoT applications in wastewater and stormwater, and the human and environmental consequences of water contaminants and their treatment. The IoT applications using sensors for sewer and stormwater monitoring across networked landscapes, water quality assessment, treatment, and sustainable management are introduced. The studies of rate limitations in biophysical and geochemical processes that support the ecosystem services related to water quality are presented. The applications of IoT solutions based on these discoveries are also discussed
Evidence for nu_mu -> nu_e Oscillations from Pion Decay in Flight Neutrinos
A search for nu_mu -> nu_e oscillations has been conducted at the Los Alamos
Meson Physics Facility using nu_mu from pi^+ decay in flight. An excess in the
number of beam-related events from the C(nu_e,e^-)X inclusive reaction is
observed. The excess is too large to be explained by normal nu_e contamination
in the beam at a confidence level greater than 99%. If interpreted as an
oscillation signal, the observed oscillation probability of (2.6 +- 1.0 +- 0.5)
x 10^{-3} is consistent with the previously reported nu_mu_bar -> nu_e_bar
oscillation evidence from LSND.Comment: 70 pages (LaTeX), 32 figures (PostScript), submitted to Phys. Rev. C.
Additional information at http://nu1.lampf.lanl.gov/~lsn
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