scholarly journals Quantum sensing for gravitational cartography

2021 ◽  
Author(s):  
Michael Holynski ◽  
Ben Stray ◽  
Andrew Lamb ◽  
Aisha Kaushik ◽  
Jamie Vovrosh ◽  
...  
Keyword(s):  
Water Distribution ◽  
Energy Transport ◽  
Signal To Noise Ratio ◽  
Critical Energy ◽  
Temporal Variations ◽  
Gravity Gradient ◽  
Ground Conditions ◽  
Bayesian Inference Method ◽  
New Applications ◽  
Vibrational Noise

Abstract The sensing of gravity has emerged as an important tool in geophysics for applications such as engineering and climate research, where it provides the capability to probe otherwise inaccessible features under the surface of the Earth. Examples include the monitoring of temporal variations such as those found in aquifers and geodesy. However, resolving metre scale underground features is rendered impractical by the long measurement times needed for the removal of vibrational noise. Here, we overcome this limitation and open up the field of gravity cartography by realising a practical quantum gravity gradient sensor. Our design suppresses the effects of micro-seismic and laser noise, as well as thermal and magnetic field variations, and instrument tilt. The instrument achieves an uncertainty of 20 E (1 E = 10^-9 s^-2) and is used to perform a 0.5 m spatial resolution survey across a 8.5 m long line, detecting a 2 m tunnel with a signal to noise ratio of 8. The tunnel centre is localised using a Bayesian inference method, determining the centre to within ± 0.19 m in the horizontal direction and finding the centre depth as (1.89 -0.59/+2.3) m. The removal of vibrational noise enables improvements in instrument performance to directly translate into reduced measurement time in mapping. This opens new applications such as mapping the water distribution of aquifers and evaluating impacts on the water table, detecting new features in archaeology, determination of soil properties and water content ,and reducing the risk of unforeseen ground conditions in the construction of critical energy, transport and utilities infrastructure, providing a new window into the underground.

Rate Compatible LDPC Codes Design for Shallow Water Acoustic Communications

2012 ◽  
Vol 198-199 ◽  
pp. 1609-1614
Author(s):  
You Gan Chen ◽  
Xiao Mei Xu ◽  
Lan Zhang
Keyword(s):  
Shallow Water ◽  
Communication System ◽  
Channel Coding ◽  
Error Control ◽  
Signal To Noise Ratio ◽  
Estimation Error ◽  
Ldpc Codes ◽  
Temporal Variations ◽  
Channel Characteristics ◽  
Wide Range

The fast temporal variations shallow water acoustic (SWA) channels need the temporal variations channel coding scheme at the acceptable cost. Hence, flexible channel coding rate, adjusted according to different ocean channel characteristics, should be desired in the design of practical error control SWA communication system. In this paper, we propose rate-compatible LDPC (RC-LDPC) codes to improve the communication system reliability for SWA communications. The proposed SWA system adopting RC-LDPC codes consists of three important preprocessing: channel state information (CSI) estimator, signal-to-noise ratio (SNR) estimator and RC-LDPC pattern. For the estimation error, we define and derive the sensitivity to imperfect CSI and imperfect SNR. Then the design of RC-LDPC codes and SWA channel profile are described. Furthermore, the RC-LDPC performance pattern is given and sensitivity to estimation error of CSI and SNR are analyzed via simulation. It is shown that RC-LDPC codes have good performances with wide range of rates in SWA channels. Finally, coding rate distributions of RC-LDPC codes in different SNR at BER below 10-4 for SWA channel are investigated.

scholarly journals The 2018 Geothermal Reservoir Stimulation in Espoo/Helsinki, Southern Finland: Seismic Network Anatomy and Data Features

2020 ◽  
Vol 91 (2A) ◽  
pp. 770-786
Author(s):  
Gregor Hillers ◽  
Tommi A. T. Vuorinen ◽  
Marja R. Uski ◽  
Jari T. Kortström ◽  
Päivi B. Mäntyniemi ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Signal To Noise Ratio ◽  
Body Wave ◽  
Temporal Variations ◽  
Seismic Network ◽  
Anthropogenic Activity ◽  
Earthquake Activity ◽  
Velocity Change ◽  
Fault Plane Solutions ◽  
Induced Earthquake

Abstract A seismic network was installed in Helsinki, Finland to monitor the response to an ∼6-kilometer-deep geothermal stimulation experiment in 2018. We present initial results of multiple induced earthquake seismogram and ambient wavefield analyses. The used data are from parts of the borehole network deployed by the operating St1 Deep Heat Company, from surface broadband sensors and 100 geophones installed by the Institute of Seismology, University of Helsinki, and from Finnish National Seismic Network stations. Records collected in the urban environment contain many signals associated with anthropogenic activity. This results in time- and frequency-dependent variations of the signal-to-noise ratio of earthquake records from a 260-meter-deep borehole sensor compared to the combined signals of 24 collocated surface array sensors. Manual relocations of ∼500 events indicate three distinct zones of induced earthquake activity that are consistent with the three clusters of seismicity identified by the company. The fault-plane solutions of 14 selected ML 0.6–1.8 events indicate a dominant reverse-faulting style, and the associated SH radiation patterns appear to control the first-order features of the macroseismic report distribution. Beamforming of earthquake data from six arrays suggests heterogeneous medium properties, in particular between the injection site and two arrays to the west and southwest. Ambient-noise cross-correlation functions reconstruct regional surface-wave propagation and path-dependent body-wave propagation. A 1D inversion of the weakly dispersive surface waves reveals average shear-wave velocities around 3.3  km/s below 20 m depth. Consistent features observed in relative velocity change time series and in temporal variations of a proxy for wavefield partitioning likely reflect the medium response to the stimulation. The resolution properties of the obtained data can inform future monitoring strategies and network designs around natural laboratories.

Spatial and temporal groupings of water main pipe breakage in Winnipeg

1988 ◽  
Vol 15 (1) ◽  
pp. 91-97 ◽  
Author(s):  
I. C. Goulter ◽  
A. Kazemi
Keyword(s):  
Water Distribution ◽  
Interval Parameter ◽  
Pipe Failure ◽  
Spatial And Temporal Patterns ◽  
Exponential Decrease ◽  
Spatial Interval ◽  
Ground Conditions ◽  
Temporal And Spatial ◽  
Pipe Breakage ◽  
The City

The spatial and temporal patterns of water distribution pipe failure in the City of Winnipeg are examined. The failures are shown to be strongly clustered in space, where 22% of the total failures examined occur within 1 m of another failure and 46% occur within 20 m of another failure. A strong temporal clustering is also apparent, with 42% of all failures that occur within 1 m of another found also to occur within 1 day of the initial failure in the group. An exponential decrease in the marginal rates of failure with respect to both the temporal and spatial interval parameter is also observed. Earlier failures in a particular location appear to be an important key to assessing potential failures in that vicinity. These results suggest that a fruitful area for further examination for the reduction of failure rates is the change in the ground conditions resulting from an initial leak and its subsequent repair. Key words: failures, groupings, marginal rates, pipes, space, time, water distribution, Winnipeg.

scholarly journals O EFEITO DA QUALIDADE DA ÁGUA NO ENTUPIMENTO DE EMISSORES E NO DESEMPENHO DE FILTROS UTILIZADOS NA IRRIGAÇÃO POR GOTEJAMENTO

Irriga ◽  
2004 ◽  
Vol 9 (2) ◽  
pp. 136-149 ◽  
Author(s):  
Tulio Assunção Pires Ribeiro ◽  
José Euclides Stipp Paterniani ◽  
Rogério Pereira da Silva Airoldi ◽  
Marcelo Jacomini Moreira da Silva
Keyword(s):  
Water Quality ◽  
Irrigation Water ◽  
Water Distribution ◽  
Irrigation System ◽  
Water Source ◽  
Temporal Variations ◽  
Biological Parameters ◽  
Trickle Irrigation ◽  
Filter Performance ◽  
Medium Risk

O EFEITO DA QUALIDADE DA ÁGUA NO ENTUPIMENTO DE  EMISSORES E NO DESEMPENHO DE FILTROS UTILIZADOS NA IRRIGAÇÃO POR GOTEJAMENTO   Túlio Assunção Pires Ribeiro; José Euclides Stipp Paterniani; Rogério Pereira da Silva Airoldi; Marcelo Jacomini Moreira da SilvaDepartamento de Água e Solo, Faculdade de Engenharia Agrícola, UNICAMP, Campinas, SP, [email protected]   1 RESUMO  O presente trabalho teve como objetivo proceder a investigação experimental de uma fonte hídrica superficial, utilizada em um sistema de irrigação por gotejamento, bem como verificar sua influência na obstrução dos gotejadores e no desempenho de dois filtros um de disco e outro de mata sintética não tecida. A água de irrigação foi clorada, empregando-se hipoclorito  de sódio. Utilizou-se água provinda de um reservatório aberto, onde foi instalado um módulo de irrigação localizada para o estudo.  Analisou-se a variação temporal da qualidade da água durante um ano, onde considerou-se os principais parâmetros físicos, químicos e biológicos da água que causam problemas de entupimentos nos emissores. O desempenho dos filtros foi feito através da comparação das concentrações dos efluentes dos filtros de disco (usualmente utilizado para este fim) e manta sintética não tecida,  em relação aos parâmetros físicos e biológicas. O grau de obstrução dos emissores foi avaliado através de ensaios de vazão que determinaram a uniformidade de distribuição da água através de dois índices, onde variou-se o número de emissores amostrados.  A pesquisa foi desenvolvida em quatro etapas de 30 dias, realizadas em diferentes estações do ano. Os resultados apontaram na água de irrigação, que os parâmetros químicos pH e o ferro apresentaram médio risco de entupimento e sulfetos de hidrogênio mostraram alto risco de entupimento.  Não houve uma diferença no desempenho do filtro de manta e de disco com relação aos parâmetros físicos e biológicos de seus efluentes.  Os valores das médias dos índices de uniformidade de distribuição de água foram bem próximos para as duas parcelas que utilizaram os dois filtros de manta e disco.  UNITERMOS: irrigação localizada, índice de uniformidade, filtração, manta sintética não tecida, tratamento químico  RIBEIRO, T. A. P.; PATERNIANI, J. E. S.; AIROLDI, R. P. da S.; SILVA, M. J. M. da THE WATER QUALITY EFFECT IN THE CLOGGING OF EMITTERS AND THE PERFORMANCE OF FILTERS UTILIZED IN THE TRICKLE IRRIGATION  2 ABSTRACT  The present work aimed to carry out an experimental investigation of a superficial water source utilized in trickle irrigation as well as verify its influence in the clogging of drippers and in the performance of two filters: a disc one and a non woven synthetic one. The irrigation water was chlorinated with sodium hypochlorite. The water used in this experiment was from an open reservoir where an experimental trickle irrigation system was installed. The temporal variations of the water quality was assessed for one year, considering the main physical, chemical and biological parameters of the water that causes clogging in the emitters. The filter performance was assessed by comparing the effluent concentration in the disc filters (normally used for this purpose) and in non-woven synthetic fabric, for physical and biological parameters. The emitter obstruction degree was assessed through flow tests which determined the uniformity of water distribution through two rates where the number of sampled emitters varied. The research was developed in four 30-day stages, carried out in different seasons of the year. For the irrigation water, the results indicated that the chemical parameters (pH) and iron showed a medium risk of clogging whereas hydrogen sulphites showed a high risk of clogging. There was not a difference in the performance of fabric and disc filters in relation to physical and biological parameters of their effluents. The average values for  water distribution uniformity rates were pretty close for the two blocks that utilized both disc and fabric filters.  KEYWORDS: trickle irrigation, uniformity index, filtration, non-woven synthetic fabrics, chemical treatment

scholarly journals Continuous monitoring system for safe managements of CO2 storage and geothermal reservoirs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Takeshi Tsuji ◽  
Tatsunori Ikeda ◽  
Ryosuke Matsuura ◽  
Kota Mukumoto ◽  
Fernando Lawrens Hutapea ◽  
...  
Keyword(s):  
Monitoring System ◽  
Continuous Monitoring ◽  
Field Experiments ◽  
Seismic Velocity ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Co2 Storage ◽  
Seismic Source ◽  
Temporal Variations ◽  
Wide Frequency Range

AbstractWe have developed a new continuous monitoring system based on small seismic sources and distributed acoustic sensing (DAS). The source system generates continuous waveforms with a wide frequency range. Because the signal timing is accurately controlled, stacking the continuous waveforms enhances the signal-to-noise ratio, allowing the use of a small seismic source to monitor extensive areas (multi-reservoir). Our field experiments demonstrated that the monitoring signal was detected at a distance of ~ 80 km, and temporal variations of the monitoring signal (i.e., seismic velocity) were identified with an error of < 0.01%. Through the monitoring, we identified pore pressure variations due to geothermal operations and rains. When we used seafloor cable for DAS measurements, we identified the monitoring signals at > 10 km far from the source in high-spatial resolution. This study demonstrates that multi-reservoir in an extensive area can be continuously monitored at a relatively low cost by combining our seismic source and DAS.

scholarly journals Comparative analysis of different probability distributions of random parameters in the assessment of water distribution system reliability

2013 ◽  
Vol 16 (2) ◽  
pp. 272-287 ◽  
Author(s):  
Giovanna Darvini
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Network Reliability ◽  
Probability Distributions ◽  
Probabilistic Approach ◽  
Temporal Variations ◽  
Random Parameters ◽  
Statistical Parameters ◽  
The Impact

During recent years, several methods based on the probabilistic approach have been proposed for the analysis of the performance of water distribution systems (WDSs). Uncertain elements are described by probabilistic laws chosen and parameterised on the basis of the network characteristics. However, the choice of the most suitable probabilistic distribution and of the statistical parameters can be difficult because of the lack of information about the WDSs. Among the stochastic parameters that affect the network performance, a fundamental role is played by the times to failure and repair of the system components. The impact of the chosen probability distributions of these fundamental variables on the evaluation of water distribution network reliability is analysed. The study is performed by using a technique capable of considering the mechanical failure of the network components, the spatial and temporal variations of the water demand and the uncertain distribution of the pipe roughness. This analysis allows quantification of the effect of any inaccuracy that may occur in the probabilistic characterisation of the random parameters.

scholarly journals Continuous monitoring system for safe managements of CO2 storage and geothermal reservoirs

2021 ◽  
Author(s):  
Takeshi Tsuji ◽  
Tatsunori Ikeda ◽  
Ryosuke Matsuura ◽  
Kota Mukumoto ◽  
Hutapea Lawrens ◽  
...  
Keyword(s):  
Monitoring System ◽  
Continuous Monitoring ◽  
Field Experiments ◽  
Seismic Velocity ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Co2 Storage ◽  
Seismic Source ◽  
Temporal Variations ◽  
Wide Frequency Range

Abstract We have developed a new continuous monitoring system based on small seismic sources and distributed acoustic sensing (DAS). The source system generates continuous waveforms with a wide frequency range. Because the signal timing is accurately controlled, stacking continuous waveforms enhances the signal-to-noise ratio, allowing the use of a small seismic source to monitor extensive areas (multi-reservoir). Our field experiments demonstrated that the monitoring signal was detected at a distance of ~80 km, and temporal variations of the monitoring signal (i.e., seismic velocity) were identified with >99.9% accuracy. Through the monitoring, we identified pore pressure variations due to geothermal operations and rains. When we used seafloor cable for DAS measurements, we identified the monitoring signals at >10 km far from the source in high-spatial resolution. This study demonstrates that multi-reservoir in an extensive area can be continuously monitored at a relatively low cost by combining our seismic source and DAS technology.

Bio-Inspired Modeling Approaches for Human Networks With Link Dissipation

2019 ◽  
Author(s):  
Varuneswara Panyam ◽  
Astrid Layton
Keyword(s):  
Transmission Lines ◽  
Water Distribution ◽  
Energy Transport ◽  
Power Transmission ◽  
Ecosystem Model ◽  
Distribution Networks ◽  
Power Grids ◽  
Power Transmission Lines ◽  
The Impact ◽  
Human Networks

Abstract Structural similarities between human networks and biological ecosystems have inspired biomimetic design of human networks. The approach requires the networks to be represented as graphs, where the actors are nodes and the connections between actors are links. A major oversight in the application of ecosystem-based modeling to human networks thus far has been in the selection of actors and links. Transfers between species in a biological ecosystem are direct, happening when the species are co-located. Human networks often require a physical aid to complete the transaction, such as power transmission lines, pipelines, or vehicles. These exchange methods experience dissipation, which is not captured in current applications of ecosystem-based human network modeling. Human networks modeled as ecosystems thus far simply categorize exchanges as links in the graph, effectively forcing dissipation during material/energy transport to be neglected. This dissipation can sometimes be high relative to the total energy/material exchanged and thus is a potentially large oversight. Three hypothetical power grids and three Italian urban water distribution networks are used to quantify the impact of modeling interaction aids — power lines and water pipelines — as actors (and thus including any dissipation) in an ecosystem model. Ecological structural and flow metrics previously applied to human networks are evaluated between the two modeling methods. The comparison shows that the impact of this overlooked aspect is potentially significant and warrants consideration.

scholarly journals Assessing Ground Support of Plastic Pipes Using Ultrasound

2021 ◽  
Vol 6 (2) ◽  
pp. 30
Author(s):  
Juanjuan Zhu ◽  
Joby B. Boxall ◽  
Andrew F. Hills ◽  
Rob S. Dwyer-Joyce ◽  
Sean R. Anderson ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Soil Conditions ◽  
Buried Pipe ◽  
Ultrasound Technique ◽  
Ground Support ◽  
Plastic Pipes ◽  
Essential Services ◽  
Ground Conditions ◽  
Continued Use

The ability to detect early signs of failure in buried pipe infrastructure is necessary to facilitate the continued use of ageing infrastructure for delivery of society’s essential services and move beyond disruptive and expensive reactive maintenance and repair. This paper reports detailed experiments on the use of in-pipe ultrasound techniques for assessment of ground conditions around buried plastic pipes. Two sets of ultrasonic experiment on the soil conditions are presented: (1) existence, shape, and dimension of void, and (2) water content in the soil. The ultrasound technique is shown to be capable for detecting water filled voids and assessing the soil support, critical early indicators of failure. The technique requires water as the transmission media hence is naturally suited to application in operational water distribution systems. The work represents an important advance in in-pipe condition assessment of plastic pipes, demonstrates the practical capability of the ultrasound technique, which is critical for progression towards proactive maintenance, offering cost and service improvements.

scholarly journals Decadal changes of surface elevation over permafrost area estimated using reflected GPS signals

2017 ◽  
Author(s):  
Lin Liu ◽  
Kristine M. Larson
Keyword(s):  
Signal To Noise Ratio ◽  
Ground Surface ◽  
Temporal Variations ◽  
Surface Elevation ◽  
Frozen Ground ◽  
Near Surface ◽  
Ratio Data ◽  
Long Time ◽  
Elevation Changes ◽  
Continuous Gps

Abstract. Conventional benchmark-based surveys and Global Positioning System (GPS) have been used to measure surface elevation changes over permafrost areas, usually once or a few times a year. Here we introduce a new method that uses reflected GPS signals to measure temporal changes of ground surface elevation due to dynamics of the active layer and near-surface permafrost. Applying the GPS interferometric reflectometry technique to the signal-to-noise-ratio data collected by a continuous GPS receiver mounted deep in permafrost in Barrow, Alaska, we can retrieve the vertical distance between the antenna and surface reflector under the antenna. Using this unique kind of observables, we obtain daily changes of surface elevation during July and August from 2004 to 2015. Our results show distinct temporal variations at three timescales: regular thaw settlement within each summer, strong inter-annual variability that is characterized by a sub-decadal subsidence trend followed by a brief uplift trend, and a secular subsidence trend of 0.26 ± 0.02 cm/year during 2004 and 2015. This method provides a new way to fully utilize data from continuous GPS sites in cold regions for studying dynamics of the frozen ground consistently and sustainably over a long time.

Sign in / Sign up

Export Citation Format

Share Document