Statistics for Spatial Data.

Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis.

Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis

By L I Sedov London: Cleaver-Hume Press Ltd Pp xvi + 363 Price 105s This is really two separate books within the same pair of covers First of all Chapters 1-3, some 145 pages, are devoted to the discussion of similarity and dimensional, methods and their application to a variety of problems in mechanics and fluid mechanics

http://iopscience.iop.org/article/10.1088/0031-9112/11/6/008/pdf

Similarity and Dimensional Methods in Mechanics

random data analysis and measurement procedures is available in our digital library an online access to it is set as public so you can get it instantly. Our book servers spans in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Merely said, the random data analysis and measurement procedures is universally compatible with any devices to read.

Random Data Analysis And Measurement Procedures

Cases of COVID-19 have been reported in over 200 countries. Thousands of health workers have been infected and outbreaks have occurred in hospitals, aged care facilities and prisons. World Health Organization (WHO) has issued guidelines for contact and droplet precautions for Healthcare Workers (HCWs) caring for suspected COVID-19 patients, whilst the US Centre for Disease Control (CDC) has recommended airborne precautions. The 1 - 2 m (≈3 - 6 ft) rule of spatial separation is central to droplet precautions and assumes large droplets do not travel further than 2 m (≈6 ft). We aimed to review the evidence for horizontal distance travelled by droplets and the guidelines issued by the World Health Organization (WHO), US Center for Diseases Control (CDC) and European Centre for Disease Prevention and Control (ECDC) on respiratory protection for COVID-19. We found that the evidence base for current guidelines is sparse, and the available data do not support the 1 - 2 m (≈3 - 6 ft) rule of spatial separation. Of ten studies on horizontal droplet distance, eight showed droplets travel more than 2 m (≈6 ft), in some cases more than 8 meters (≈26 ft). Several studies of SARS-CoV-2 support aerosol transmission and one study documented virus at a distance of 4 meters (≈13 ft) from the patient. Moreover, evidence suggests infections cannot neatly be separated into the dichotomy of droplet versus airborne transmission routes. Available studies also show that SARS-CoV-2 can be detected in the air, 3 hours after aeroslisation. The weight of combined evidence supports airborne precautions for the occupational health and safety of health workers treating patients with COVID-19.

/pdf/airborne-or-droplet-precautions-for-health-workers-treating-3f4myu4r8t.pdf

Airborne or droplet precautions for health workers treating COVID-19?

This paper presents the results of an experimental investigation exploring the noise-reduction potential of sawtooth trailing-edge serrations on a flat plate at low-to-moderate Reynolds number (1.6×105<Rec<4.2×105). Acoustic measurements have been taken using a flat plate with both sharp and serrated trailing edges in an anechoic wind tunnel. Trailing-edge serrations are found to achieve reductions of up to 13 dB in the narrowband noise levels, and this is mainly due to attenuation of vortex shedding at the trailing edge. Velocity data have also been measured in the very-near trailing-edge wake using hot-wire anemometry, and these data are related to the far-field noise measurements to give insight into the trailing-edge serration noise-reduction mechanism. The results show that, for this particular configuration, the noise-reduction mechanism of trailing-edge serrations is dominated by their influence on the hydrodynamic field at the source location. Therefore, the assumption that the turbulent field is ...

Noise-Reduction Mechanism of a Flat-Plate Serrated Trailing Edge

Flows over a square cylinder of side length D with and without a splitter plate are numerically investigated at a Reynolds number of 150. The length of the splitter plate is varied systematically from L=0.5D to L=6D so the sensitivity of the flow structure to the inclusion of the splitter plate can be inspected. It is found that the splitter plate introduces a strong hydrodynamic interaction to the near wake of the cylinder and the length of the plate affects significantly the flow structure. The behavior of the flow can be grouped into three regimes. For short plate lengths (0≲L≲D), the free shear layers are convected further downstream before rolling up when the plate length is increased. For intermediate plate lengths (1.25D≲L≲4.75D), a secondary vortex is clearly visible around the trailing edge of the splitter plate and the shear layers begin to roll up closer to the trailing edge. For long plate lengths (L≳5D), a regime is observed in which the free shear layers reattach to the splitter plate. The study also proposes the minimum wake half-width as the length scale for a possible universal Strouhal number, which is found to be valid for 0≤L≤4D. © 2011 American Institute of Physics.

Low Reynolds number flow over a square cylinder with a splitter plate

A review of flow-induced noise from finite wall-mounted cylinders

This paper describes a systematic method of refining a computational grid for the Direct Numerical Simulation (DNS) of flow about a square cylinder. The grid refinement method involves two stages. The first stage constructs computational meshes based on reasonable estimates of cell size and grid stretching ratios and investigates the sensitivity of the computed flow field to these parameters. The findings from this stage are used as a guide for further grid refinement. In the second stage, the grid is divided into four regions to minimise the grid stretching ratio. The smallest cell is sized so the boundary layer on the front face of the cylinder is adequately resolved. Solutions on seven different grids are presented to investigate the effect of numerical scheme, boundary conditions and grid independence. The level of grid independence is evaluated using a form of Richardson extrapolation and the study shows that the finest grid solution has a Grid Convergence Index (GCI) of less than 5%.

/pdf/grid-convergence-study-for-a-two-dimensional-simulation-of-ea6q0wgypx.pdf

Con J. Doolan

Papers

Airborne or droplet precautions for health workers treating COVID-19?

Noise-Reduction Mechanism of a Flat-Plate Serrated Trailing Edge

Low Reynolds number flow over a square cylinder with a splitter plate

A review of flow-induced noise from finite wall-mounted cylinders

Grid convergence study for a two-dimensional simulation of flow around a square cylinder at a low reynolds number