Modeling high flow speeds in the inner corona

1996 ◽  
Author(s):  
Ruth Esser ◽  
Shadia Rifai Habbal
Keyword(s):  
High Flow ◽  
Flow Speeds

scholarly journals Upstream rheotaxis of catalytic Janus spheres

2021 ◽  
Author(s):  
Priyanka Sharan ◽  
Zuyao Xiao ◽  
Viviana Mancuso ◽  
William E. Uspal ◽  
Juliane Simmchen
Keyword(s):  
Fluid Flow ◽  
Type System ◽  
Shear Plane ◽  
High Flow ◽  
Physical Factors ◽  
Theoretical Studies ◽  
Directional Response ◽  
Swimming Pattern ◽  
Flow Speeds ◽  
Stream Migration

Fluid flow is ubiquitous in many environments that form habitats for microorganisms. The tendency of organisms to navigate towards or away from flow is termed rheotaxis. Therefore, it is not surprising that both biological and artificial microswimmers show responses to flows that are determined by the interplay of chemical and physical factors. In particular, to deepen understanding of how different systems respond to flows, it is crucial to comprehend the influence played by swimming pattern. In recent studies, pusher-type Janus particles exhibited cross-stream migration in externally applied flows. Earlier, theoretical studies predicted a positive rheotactic response for puller-type spherical Janus micromotors. To compare to a different swimmer, we introduce Cu@SiO2 micromotors that swim towards their catalytic cap. Based on experimental observations, and supported by flow field calculations using a model for self-electrophoresis, we hypothesize that they behave effectively as a puller-type system. We investigate the effect of externally imposed flow on these spherically symmetrical Cu@SiO2 active Janus colloids, and we indeedobserve a steady upstream directional response. Through a simple squirmer model for a puller, we recover the major experimental observations. Additionally, the model predicts a unique “jumping” behaviour for puller-type micro- motors at high flow speeds. Performing additional experiments at high flow speeds, we capture this phenomenon, in which the particles “roll” with their swimming axes aligned to the shear plane, in addition to being dragged down- stream by the fluid flow.

Performance of Undershot Waterwheel Curved Blade of the Laboratory Scale

2019 ◽  
Vol 967 ◽  
pp. 250-255
Author(s):  
Irwan Lie Keng Wong ◽  
Atus Buku ◽  
Josefine Ernestine Latupeirissa ◽  
Herby Calvin Pascal Tiwouy
Keyword(s):  
Rural Areas ◽  
High Speed ◽  
Large Diameter ◽  
Small Diameter ◽  
Water Source ◽  
High Flow ◽  
The People ◽  
Flow Speeds ◽  
Curved Blade ◽  
High Torque

Undershot waterwheels have been used by the people in rural areas to lift and distribute the water to the bottom which is higher than the water source. Waterwheels has a relatively simple design, large diameter, high speed and high torque. But applying it as a microhydro with high speed and small diameter still has to be explored. Waterwheels can operate efficiently in locations with high flow speeds. The Waterwheel functions from a waterwheel blade as a place to ride water so that the wheel can spin. From the results of the study, it can be concluded that the higher the flow of water with a large number of buckets, the speed of rotation of the wheel will be slower. Conversely, the lower the flow of water with the number of buckets a little then the spinning wheel is faster.

scholarly journals Influence of benthic currents on cold-water coral habitats: a combined benthic monitoring and 3D photogrammetric investigation

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Aaron Lim ◽  
Andrew J. Wheeler ◽  
David M. Price ◽  
Luke O’Reilly ◽  
Kimberley Harris ◽  
...  
Keyword(s):  
Cold Water ◽  
Field Measurements ◽  
High Flow ◽  
High Temporal Resolution ◽  
Live Coral ◽  
Current Profile ◽  
Coral Rubble ◽  
Flow Speeds ◽  
Water Coral

Abstract Strong currents are a key component of benthic habitats by supplying food and nutrients to filter-feeding organisms such as cold-water corals. Although field measurements show that cold-water coral habitats exist in areas of elevated bottom currents, flume studies show that cold-water corals feed more effectively at lower flow speeds. This research aims to explore this disconnect in situ by utilising high spatial resolution ROV photogrammetric data coupled with high temporal resolution in situ acoustic doppler current profile measurements at seven study sites within the upper Porcupine Bank Canyon (uPBC), NE Atlantic. Object-based image analysis of photogrammetric data show that coral habitats vary considerably within the upper canyon. Although there is a regional hydrodynamic trend across the uPBC, this variation is likely driven locally by topographic steering. Although live coral tends not to face directly into the prevailing current direction, preferring lower local flows speeds, they can tolerate exposure to high-flow speeds of up to 114 cm s−1, the highest recorded in a Desmophyllum pertusum habitat. Not only do these high flow speeds supply food and nutrients, they may also help contribute to coral rubble production through physical erosion. These results can be incorporated into simulations of future deep-water habitat response to changing environmental conditions while extending the upper current speed threshold for cold-water corals.

Anisotropic Membranes as Substrates for Sem

1976 ◽  
Vol 34 ◽  
pp. 444-445
Author(s):  
Thomas P. Turnbull ◽  
W. F. Bowers
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Flow ◽  
Polymer Chemistry ◽  
Surface Porosity ◽  
Transmission Electron ◽  
Pore Texture ◽  
Spongy Layer ◽  
Scanning Electron

Until recently the prime purposes of filters have been to produce clear filtrates or to collect particles from solution and then remove the filter medium and examine the particles by transmission electron microscopy. These filters have not had the best characteristics for scanning electron microscopy due to the size of the pores or the surface topography. Advances in polymer chemistry and membrane technology resulted in membranes whose characteristics make them versatile substrates for many scanning electron microscope applications. These polysulphone type membranes are anisotropic, consisting of a very thin (0.1 to 1.5 μm) dense skin of extremely fine, controlled pore texture upon a much thicker (50 to 250μm), spongy layer of the same polymer. Apparent pore diameters can be controlled in the range of 10 to 40 A. The high flow ultrafilters which we are describing have a surface porosity in the range of 15 to 25 angstrom units (0.0015-0.0025μm).

High Flow Oxygen Therapy and the Pressure to Feed Infants With Acute Respiratory Illness

2020 ◽  
Vol 5 (4) ◽  
pp. 1006-1010
Author(s):  
Jennifer Raminick ◽  
Hema Desai
Keyword(s):  
Clinical Practice ◽  
Clinical Practice Guidelines ◽  
Practice Guidelines ◽  
Oxygen Therapy ◽  
Respiratory Illness ◽  
High Flow ◽  
Oral Feeding ◽  
Respiratory Support ◽  
Acute Respiratory Illness ◽  
High Flow Oxygen

Purpose Infants hospitalized for an acute respiratory illness often require the use of noninvasive respiratory support during the initial stage to improve their breathing. High flow oxygen therapy (HFOT) is becoming a more popular means of noninvasive respiratory support, often used to treat respiratory syncytial virus/bronchiolitis. These infants present with tachypnea and coughing, resulting in difficulties in coordinating sucking and swallowing. However, they are often allowed to feed orally despite having high respiratory rate, increased work of breathing and on HFOT, placing them at risk for aspiration. Feeding therapists who work with these infants have raised concerns that HFOT creates an additional risk factor for swallowing dysfunction, especially with infants who have compromised airways or other comorbidities. There is emerging literature concluding changes in pharyngeal pressures with HFOT, as well as aspiration in preterm neonates who are on nasal continuous positive airway pressure. However, there is no existing research exploring the effect of HFOT on swallowing in infants with acute respiratory illness. This discussion will present findings from literature on HFOT, oral feeding in the acutely ill infant population, and present clinical practice guidelines for safe feeding during critical care admission for acute respiratory illness. Conclusion Guidelines for safety of oral feeds for infants with acute respiratory illness on HFOT do not exist. However, providers and parents continue to want to provide oral feeds despite clinical signs of respiratory distress and coughing. To address this challenge, we initiated a process change to use clinical bedside evaluation and a “cross-systems approach” to provide recommendations for safer oral feeds while on HFOT as the infant is recovering from illness. Use of standardized feeding evaluation and protocol have improved consistency of practice within our department. However, further research is still necessary to develop clinical practice guidelines for safe oral feeding for infants on HFOT.

High-Flow-Sauerstofftherapie in der Notaufnahme – Schritt für Schritt

2020 ◽  
Vol 2 (04) ◽  
pp. 327-335
Author(s):  
Markus Bald ◽  
Carl Josef Hocke
Keyword(s):  
High Flow
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