Implementation of preventive measures against local flow degradation in the primary circuit of RBMK-1500

COVID-19 has shown a high potential of transmission via virus-carrying aerosols as supported by growing evidence. However, detailed investigations that draw direct links between aerosol transport and virus infection are still lacking. To fill in the gap, we conducted a systematic computational fluid dynamics (CFD)-based investigation of indoor air flow and the associated aerosol transport in a restaurant setting, where likely cases of airborne infection of COVID-19 caused by asymptomatic individuals were widely reported by the media. We employed an advanced in-house large eddy simulation (LES) solver and other cutting-edge numerical methods to resolve complex indoor processes simultaneously, including turbulence, flow–aerosol interplay, thermal effect, and the filtration effect by air conditioners. Using the aerosol exposure index derived from the simulation, we are able to provide a spatial map of the airborne infection risk under different settings. Our results have shown a remarkable direct linkage between regions of high aerosol exposure index and the reported infection patterns in the restaurant, providing strong support to the airborne transmission occurring in this widely-reported incidence. Using flow structure analysis and reverse-time tracing of aerosol trajectories, we are able to further pinpoint the influence of environmental parameters on the infection risks and highlight the needs for more effective preventive measures, e.g., placement of shielding according to the local flow patterns. Our research, thus, has demonstrated the capability and value of high-fidelity CFD tools for airborne infection risk assessment and the development of effective preventive measures.

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Analysis of Fracture Mechanics Specimens Made of Inconel 600 Based on Assessment Methods of Different Complexity

Volume 6: Materials and Fabrication, Parts A and B ◽

10.1115/pvp2009-77195 ◽

2009 ◽

Author(s):

Tomas Nicak ◽

Herbert Schendzielorz ◽

Elisabeth Keim

Keyword(s):

Fracture Mechanics ◽

Crack Growth ◽

Assessment Methods ◽

Primary Circuit ◽

Special Focus ◽

Worst Case ◽

Local Flow ◽

Inconel 600 ◽

Safety Margins ◽

Micromechanical Models

Fracture mechanics analysis plays an important role in the frame of the safety assessment of nuclear components. Usually the goal of such an analysis is to decide if a given flaw size in the piping (or any component of the primary circuit) is acceptable or not. The word “acceptable” means that structural integrity of the component is guaranteed with sufficient safety margins up to the end of service life or up to the next in-service inspection (considering the worst case loads and lower bound material properties). To fulfil this high-responsible task in practice some useful Engineering Assessment methods (EAM) have been established i.e. Local flow stress concept (Germany), assessment based on J-Integral (France RSE-M), Limit load calculation according to (ASME XI, USA) or Two criteria approach (R6, UK). These EAM are verified by a large number of testscarried out in the past. On a higher level, more advanced assessment methods have been developed during the last years, based on micromechanical models of void nucleation and growth. These advanced micromechanical models are used within the Finite Element Analysis (FEA) and allow to study the whole crack growth process from initiation to final failure in more detail. In the ductile regime, which is the typical case for application of aforementioned methods, the crack growth can be divided into three phases: crack initiation, stable crack growth and unstable crack growth. In this paper methods of different complexity will be applied to analyse fracture mechanics specimens made of Inconel 600. Special focus will be placed on the crack growth modelling based on the Gurson’s porous metal plasticity theory. All performed calculations will be compared with experiments.

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Quantitative analysis of in situ straining experiments in the case of strong frictional forces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109999 ◽

1978 ◽

Vol 36 (1) ◽

pp. 570-571

Author(s):

F. Louchet ◽

L.P. Kubin

Keyword(s):

Strain Rate ◽

Radiation Effects ◽

Dislocation Line ◽

Critical Length ◽

Local Strain ◽

Local Flow ◽

Double Kink ◽

Dislocation Densities ◽

Frictional Forces ◽

Local Strain Rate

Investigation of frictional forces -Experimental techniques and working conditions in the high voltage electron microscope have already been described (1). Care has been taken in order to minimize both surface and radiation effects under deformation conditions.Dislocation densities and velocities are measured on the records of the deformation. It can be noticed that mobile dislocation densities can be far below the total dislocation density in the operative system. The local strain-rate can be deduced from these measurements. The local flow stresses are deduced from the curvature radii of the dislocations when the local strain-rate reaches the values of ∿ 10-4 s-1.For a straight screw segment of length L moving by double-kink nucleation between two pinning points, the velocity is :where ΔG(τ) is the activation energy and lc the critical length for double-kink nucleation. The term L/lc takes into account the number of simultaneous attempts for double-kink nucleation on the dislocation line.

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Abstract #500: Osteoporosis Preventive Measures in Patients Receiving Glucocorticoids - are they Being Practiced?

Endocrine Practice ◽

10.1016/s1530-891x(20)42637-0 ◽

2015 ◽

Vol 21 ◽

pp. 97

Author(s):

Nitika Malhotra ◽

Reem Alnazawi ◽

Ved Gossain ◽

Matthew Hebdon

Keyword(s):

Preventive Measures

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Fatality of Suicide Attempts in Amsterdam 1996–2005

Crisis ◽

10.1027/0227-5910.30.4.180 ◽

2009 ◽

Vol 30 (4) ◽

pp. 180-185 ◽

Cited By ~ 10

Author(s):

Evertjan Jansen ◽

Marcel C.A. Buster ◽

Annemarie L. Zuur ◽

Cees Das

Keyword(s):

Health Service ◽

Time Trends ◽

Suicide Attempts ◽

Preventive Measures ◽

Case Fatality ◽

Absolute Number ◽

Demographic Differences ◽

Demographic Groups ◽

Wish To Die ◽

Municipal Health

Background: According to recent figures, Amsterdam is the municipality with the highest absolute number of suicides and the second highest suicide rate in the Netherlands. Aims: The aim of the study was to identify time trends and demographic differences in the occurrence of nonfatal suicide attempts versus suicides. Methods: We used registrations of forensic physicians and ambulance services of the Municipal Health Service of Amsterdam to study 1,004 suicides and 6,166 nonfatal attempts occurring in Amsterdam over the period 1996–2005. Results: The number of nonfatal attempts declined from 1996 to 2005, but the number of completed suicides remained relatively stable. Although case fatality was strongly associated with method used, we also found higher case fatalities for men and older people independent of method. Conclusions: The case fatality results suggest differences in motive among different demographic groups: possibly the wish to die is stronger among men and elderly. This finding had implications for the success to be expected from different preventive measures.

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