scholarly journals Large Scale Modelling of Damage and Failure of Nuclear Graphite Moderated Reactor

2022 ◽  
Author(s):  
Ahmadreza Farrokhnia ◽  
Andrey P. Jivkov ◽  
Graham Hall ◽  
Paul Mummery
Keyword(s):  
Large Scale ◽  
Life Extension ◽  
Structural Function ◽  
Major Step ◽  
Damage And Failure ◽  
The Core ◽  
Nuclear Graphite ◽  
Fidelity Assessment ◽  
Scale Modelling ◽  
The Uk

Abstract The UK Advanced Gas-Cooled reactors (AGRs) have cores made of graphite bricks with dual functions: as structural elements of the core, providing space for and separating fuel and control rods; and as moderator of the nuclear reaction. Nuclear graphite is a quasi-brittle material, where the dominant mechanism for failure is cracking. While cracking of isolated bricks is expected due to operation-induced changes in graphite microstructure and stress fields, these could be tolerated as far as the overall structural function of the core is maintained. Assessment of the whole core behaviour has been previously done with whole scale models where bricks have been considered as rigid body elements connected by elastic-brittle springs. This approach does not allow for the realistic assessment of the stresses in the bricks and associated brick cracking. Reported here are results from an ongoing project, which addresses this shortcoming. The proposed model uses deformable bricks with appropriate interactions, allowing for physically realistic whole core analysis. The results are focused on the damage that a graphite moderated reactor develops during a life cycle, how this affects the behaviour of the whole core, and how changes in bricks' behaviour impacts the core integrity. The proposed methodology is a major step towards high-fidelity assessment of AGRs' fitness for service, required for supporting continuous safe operation and life-extension decisions.

Origin and distribution of dolomite in Permian Rotliegend siliciclastic sandstones (Dutch Southern Permian Basin)

2019 ◽  
Vol 89 (10) ◽  
pp. 1055-1073 ◽  
Author(s):  
Nicolaas Molenaar ◽  
Marita Felder
Keyword(s):  
Large Scale ◽  
Permian Basin ◽  
Advective Flow ◽  
Gas Reservoirs ◽  
Carbonate Cement ◽  
Thin Section Petrography ◽  
The Uk ◽  
Pressure Dissolution ◽  
Dolomite Cement ◽  
Detrital Carbonate

ABSTRACT Dolomite is a common and volumetrically important mineral in many siliciclastic sandstones, including Permian Rotliegend sandstones (the Slochteren Formation). These sandstones form extensive gas reservoirs in the Southern Permian Basin in the Netherlands, Germany, Poland, and the UK. The reservoir quality of these sandstones is negatively influenced by the content and distribution of dolomite. The origin and the stratigraphic distribution of the dolomite is not yet fully understood. The aim of this study is to identify the origin of carbonate. The main methods used to achieve those aims are a combination of thin-section petrography, scanning electron microscopy (SEM and EDX), and XRD analyses. The present study shows that the typical dispersed occurrence of the dolomite is a consequence of dispersed detrital carbonate grains that served both as nuclei and source for authigenic dolomite cement. The dolomite cement formed syntaxial outgrowths and overgrowths around detrital carbonate grains. The study also shows that dolomite cement, often in combination with ankerite and siderite, precipitated during burial after mechanical compaction. Most of the carbonate grains consisted of dolomite before deposition. The carbonate grains were affected by compaction and pressure dissolution, and commonly have no well-defined outlines anymore. The distribution of dolomite cement in the Rotliegend sandstones was controlled by the presence of stable carbonate grains. Due to the restricted and variable content of carbonate grains and their dispersed occurrence, the cement is also dispersed and the degree of cementation heterogeneous. Our findings have important implications on diagenesis modeling. The presence of detrital carbonate excludes the need for external supply by any large-scale advective flow of diagenetic fluids. By knowing that the carbonate source is local and related to detrital grains instead of being externally derived from an unknown source, the presence of carbonate cement can be linked to a paleogeographic and sedimentological model.

scholarly journals Fidelity to an evidence-based model for crisis resolution teams: a cross-sectional multicentre study in Norway

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
N. Hasselberg ◽  
K. H. Holgersen ◽  
G. M. Uverud ◽  
J. Siqveland ◽  
B. Lloyd-Evans ◽  
...  
Keyword(s):  
Mental Health ◽  
Multidisciplinary Teams ◽  
Evidence Based ◽  
Crisis Resolution ◽  
Health Crisis ◽  
The Core ◽  
Crisis Resolution Teams ◽  
Fidelity Scale ◽  
The Uk ◽  
Evidence Based Model

Abstract Background Crisis resolution teams (CRTs) are specialized multidisciplinary teams intended to provide assessment and short-term outpatient or home treatment as an alternative to hospital admission for people experiencing a mental health crisis. In Norway, CRTs have been established within mental health services throughout the country, but their fidelity to an evidence-based model for CRTs has been unknown. Methods We assessed fidelity to the evidence-based CRT model for 28 CRTs, using the CORE Crisis Resolution Team Fidelity Scale Version 2, a tool developed and first applied in the UK to measure adherence to a model of optimal CRT practice. The assessments were completed by evaluation teams based on written information, interviews, and review of patient records during a one-day visit with each CRT. Results The fidelity scale was applicable for assessing fidelity of Norwegian CRTs to the CRT model. On a scale 1 to 5, the mean fidelity score was low (2.75) and with a moderate variation of fidelity across the teams. The CRTs had highest scores on the content and delivery of care subscale, and lowest on the location and timing of care subscale. Scores were high on items measuring comprehensive assessment, psychological interventions, visit length, service users’ choice of location, and of type of support. However, scores were low on opening hours, gatekeeping acute psychiatric beds, facilitating early hospital discharge, intensity of contact, providing medication, and providing practical support. Conclusions The CORE CRT Fidelity Scale was applicable and relevant to assessment of Norwegian CRTs and may be used to guide further development in clinical practice and research. Lower fidelity and differences in fidelity patterns compared to the UK teams may indicate that Norwegian teams are more focused on early interventions to a broader patient group and less on avoiding acute inpatient admissions for patients with severe mental illness.

scholarly journals Establishment and lineage dynamics of the SARS-CoV-2 epidemic in the UK

Science ◽  
2021 ◽  
pp. eabf2946
Author(s):  
Louis du Plessis ◽  
John T. McCrone ◽  
Alexander E. Zarebski ◽  
Verity Hill ◽  
Christopher Ruis ◽  
...  
Keyword(s):  
Large Scale ◽  
Phylogenetic Analyses ◽  
Transmission Dynamics ◽  
Genetic Lineage ◽  
Size Dependent ◽  
Spatio Temporal ◽  
The Uk ◽  
Lineage Structure ◽  
And Control ◽  
Lineage Diversity

The UK’s COVID-19 epidemic during early 2020 was one of world’s largest and unusually well represented by virus genomic sampling. Here we reveal the fine-scale genetic lineage structure of this epidemic through analysis of 50,887 SARS-CoV-2 genomes, including 26,181 from the UK sampled throughout the country’s first wave of infection. Using large-scale phylogenetic analyses, combined with epidemiological and travel data, we quantify the size, spatio-temporal origins and persistence of genetically-distinct UK transmission lineages. Rapid fluctuations in virus importation rates resulted in >1000 lineages; those introduced prior to national lockdown tended to be larger and more dispersed. Lineage importation and regional lineage diversity declined after lockdown, while lineage elimination was size-dependent. We discuss the implications of our genetic perspective on transmission dynamics for COVID-19 epidemiology and control.

scholarly journals Collateral impact of COVID-19: why should children continue to suffer?

2021 ◽  
Author(s):  
Prasad Nagakumar ◽  
Ceri-Louise Chadwick ◽  
Andrew Bush ◽  
Atul Gupta
Keyword(s):  
Young People ◽  
Large Scale ◽  
Hospital Admissions ◽  
Severe Disease ◽  
Children And Young People ◽  
Collateral Effects ◽  
Rsv Infection ◽  
Syncytial Virus ◽  
Set Up ◽  
The Uk

AbstractThe COVID-19 pandemic caused by SARS-COV-2 virus fortunately resulted in few children suffering from severe disease. However, the collateral effects on the COVID-19 pandemic appear to have had significant detrimental effects on children affected and young people. There are also some positive impacts in the form of reduced prevalence of viral bronchiolitis. The new strain of SARS-COV-2 identified recently in the UK appears to have increased transmissibility to children. However, there are no large vaccine trials set up in children to evaluate safety and efficacy. In this short communication, we review the collateral effects of COVID-19 pandemic in children and young people. We highlight the need for urgent strategies to mitigate the risks to children due to the COVID-19 pandemic. What is Known:• Children and young people account for <2% of all COVID-19 hospital admissions• The collateral impact of COVID-19 pandemic on children and young people is devastating• Significant reduction in influenza and respiratory syncytial virus (RSV) infection in the southern hemisphere What is New:• The public health measures to reduce COVID-19 infection may have also resulted in near elimination of influenza and RSV infections across the globe• A COVID-19 vaccine has been licensed for adults. However, large scale vaccine studies are yet to be initiated although there is emerging evidence of the new SARS-COV-2 strain spreading more rapidly though young people.• Children and young people continue to bear the collateral effects of COVID-19 pandemic

scholarly journals Multi-scale modelling of a large scale shell-and-tube latent heat storage system for direct steam generation power plants

2020 ◽  
Author(s):  
Clément Beust ◽  
Erwin Franquet ◽  
Jean-Pierre Bédécarrats ◽  
Pierre Garcia ◽  
Jérôme Pouvreau ◽  
...  
Keyword(s):  
Power Plants ◽  
Large Scale ◽  
Storage System ◽  
Steam Generation ◽  
Latent Heat Storage ◽  
Multi Scale ◽  
Direct Steam ◽  
Scale Modelling ◽  
Shell And Tube ◽  
Generation Power

scholarly journals Using Convolutional Neural Networks to Map Houses Suitable for Electric Vehicle Home Charging

AI ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 135-149
Author(s):  
James Flynn ◽  
Cinzia Giannetti
Keyword(s):  
Neural Networks ◽  
Deep Learning ◽  
Urban Areas ◽  
Proof Of Concept ◽  
Major Step ◽  
Dominant Form ◽  
Residential Properties ◽  
The Uk ◽  
Ev Charging ◽  
Unique Dataset

With Electric Vehicles (EV) emerging as the dominant form of green transport in the UK, it is critical that we better understand existing infrastructures in place to support the uptake of these vehicles. In this multi-disciplinary paper, we demonstrate a novel end-to-end workflow using deep learning to perform automated surveys of urban areas to identify residential properties suitable for EV charging. A unique dataset comprised of open source Google Street View images was used to train and compare three deep neural networks and represents the first attempt to classify residential driveways from streetscape imagery. We demonstrate the full system workflow on two urban areas and achieve accuracies of 87.2% and 89.3% respectively. This proof of concept demonstrates a promising new application of deep learning in the field of remote sensing, geospatial analysis, and urban planning, as well as a major step towards fully autonomous artificially intelligent surveying techniques of the built environment.

scholarly journals Air Maidans, Can It Be?

Societies ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 75
Author(s):  
Zeynep Correia
Keyword(s):  
United States ◽  
Production Process ◽  
Urban Infrastructure ◽  
The United States ◽  
Capital Movement ◽  
Space Technology ◽  
The Core ◽  
Public Expression ◽  
The Uk

Airports are located at the core of the production process, but can they also be where the “revolutionary subject” is hidden? We know what airports stand for nowadays, but have we pushed for what they could possibly stand for? Can airports, as a form of urban technology, be reimagined beyond their current roles of a “space technology nexus” driving capital movement? Can we imagine, idealize, and locate them somewhere else in a period dominated by the economy of time, where speed and accessibility matter the most? In this framework, this provocative essay aims to frame airports as a protest and public expression venue. Drawing inspiration from recent examples, such as the Stansted Airport protests in the UK, the Occupy Airports protests that occurred all around the United States, and touching upon the divergent example of Turkey’s 15th of July night protests in 2016, I provide a glimpse of an alternative prospect for this key urban infrastructure.

scholarly journals Creating restoration landscapes: partnerships in large-scale conservation in the UK

2016 ◽  
Vol 21 (3) ◽  
Author(s):  
William M. Adams ◽  
Ian D. Hodge ◽  
Nicholas A. Macgregor ◽  
Lindsey C. Sandbrook
Keyword(s):  
Large Scale ◽  
The Uk

scholarly journals ON GENERATING DIGITAL ELEVATION MODELS FROM LIDAR DATA – RESOLUTION VERSUS ACCURACY AND TOPOGRAPHIC WETNESS INDEX INDICES IN NORTHERN PEATLANDS

2012 ◽  
Vol 38 (2) ◽  
pp. 57-69 ◽  
Author(s):  
Abdulghani Hasan ◽  
Petter Pilesjö ◽  
Andreas Persson
Keyword(s):  
Large Scale ◽  
Drainage Area ◽  
Data Sets ◽  
Topographic Wetness Index ◽  
Absolute Deviation ◽  
Digital Elevation ◽  
Elevation Data ◽  
Scale Modelling ◽  
Data Points ◽  
Emission Modelling

Global change and GHG emission modelling are dependent on accurate wetness estimations for predictions of e.g. methane emissions. This study aims to quantify how the slope, drainage area and the TWI vary with the resolution of DEMs for a flat peatland area. Six DEMs with spatial resolutions from 0.5 to 90 m were interpolated with four different search radiuses. The relationship between accuracy of the DEM and the slope was tested. The LiDAR elevation data was divided into two data sets. The number of data points facilitated an evaluation dataset with data points not more than 10 mm away from the cell centre points in the interpolation dataset. The DEM was evaluated using a quantile-quantile test and the normalized median absolute deviation. It showed independence of the resolution when using the same search radius. The accuracy of the estimated elevation for different slopes was tested using the 0.5 meter DEM and it showed a higher deviation from evaluation data for steep areas. The slope estimations between resolutions showed differences with values that exceeded 50%. Drainage areas were tested for three resolutions, with coinciding evaluation points. The model ability to generate drainage area at each resolution was tested by pair wise comparison of three data subsets and showed differences of more than 50% in 25% of the evaluated points. The results show that consideration of DEM resolution is a necessity for the use of slope, drainage area and TWI data in large scale modelling.

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