scholarly journals The structure and function of the sucker systems of hill stream loaches

2019 ◽  
Author(s):  
Jay Willis ◽  
Theresa Burt de Perera ◽  
Cait Newport ◽  
Guillaume Poncelet ◽  
Craig J Sturrock ◽  
...  
Keyword(s):  
Total Internal Reflection ◽  
High Speed ◽  
Structural Variation ◽  
High Flow ◽  
Skeletal Structure ◽  
Video Capture ◽  
Flow Rates ◽  
Frustrated Total Internal Reflection ◽  
Vertical Glass ◽  
And Function

AbstractHill stream loaches (family Balitoridae and Gastromyzontidae) are thumb-sized fish that effortlessly exploit environments where flow rates are so high that potential competitors would be washed away. To cope with these extreme flow rates hill stream loaches have evolved adaptations to stick to the bottom, equivalent to the downforce generating wings and skirts of F1 racing cars, and scale architecture reminiscent of the drag-reducing riblets of Mako sharks. Hill stream loaches exhibit far more diverse flow-modifying morphological features than fast pelagic predators, suggesting as yet unknown drag reducing systems remain to be discovered. Here we describe the skeletal structure of Sewellia lineolata and Gastromyzon punctulatus and contrast that with other fish that face similar hydrodynamic challenges. We identify a major structural variation within Balitoridae pelvic sucker attachment positions which may explain fundamental constraints on the parallel development of different genera and which has not been described before. We also use high speed video capture, CT scans and Frustrated Total Internal Reflection to image and measure the sucker system in live operation and describe how it functions on a familiar activity for hill stream loaches (climbing waterfalls). We show how they can drag 3 to 4 times their own bodyweight up a vertical glass waterfall. Adaptations to high flow rates are the inspiration for this study, because there are many engineering applications where the ability to deal with high flow rates are important - either by reducing drag, or by generating the forces needed to hold an animal in place.

Impact of Dynamics on the Losses at Radial Ball Piston Pump Interfaces

2020 ◽  
Author(s):  
Garrett Bohach ◽  
Md Minal Nahin ◽  
Eric Severson ◽  
James D. Van de Ven
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
High Flow ◽  
The Other ◽  
Piston Pump ◽  
Flow Rates ◽  
Optimization Framework ◽  
Radial Forces ◽  
Gap Height ◽  
Rotor Model

Abstract This paper presents a mathematical model of a radial ball piston pump/motor. The specific application of the pump is for direct integration with a high speed electric motor for use in off highway vehicles. The pump/motor must operate across all four quadrants with high flow rates at a low pressure differential. The model captures the major mechanical and volumetric losses within the hydraulic machine with specific attention given to the ball-cylinder interface and the pintle-rotor interface. The leakage and shear at the ball piston interface are dependent on the position of the ball piston in the cylinder; therefore, the dynamics of the ball piston are calculated. The pintle-rotor model includes the port geometry, which influences the flow rates into and out of the pump/motor. Leakage and shear at the interface are dependent on the gap height between the two surfaces; consequently, the model calculates the radial forces acting on the rotor and uses journal bearing theory to predict the eccentricity. This eccentricity balances the other forces and is necessary to determine the interface losses. Lastly, the importance of these dynamics is evaluated to determine which are needed in a future optimization framework. It is shown that considering the dynamics of both interfaces captures significantly more losses and results in a more accurate model than an earlier simplified one.

Comparison of sensitivity of the refractometric methods of frustrated total internal reflection and surface plasmon resonance

2020 ◽  
pp. 44-49
Author(s):  
I. N. Pavlov
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Total Internal Reflection ◽  
Resonance Method ◽  
Internal Reflection ◽  
Optical Methods ◽  
Thin Boundary Layer ◽  
Experimental Conditions ◽  
Frustrated Total Internal Reflection

Two optical methods, namely surface plasmon resonance imaging and frustrated total internal reflection, are described in the paper in terms of comparing their sensitivity to change of refractive index of a thin boundary layer of an investigated medium. It is shown that, despite the fact that the theoretically calculated sensitivity is higher for the frustrated total internal reflection method, and the fact that usually in practice the surface plasmon resonance method, on the contrary, is considered more sensitive, under the same experimental conditions both methods show a similar result.

Monitoring Effects of Catchment Management Practices on Phosphorus Loads into the Eutrophic Peel-Harvey Estuary, Western Australia

1986 ◽  
Vol 18 (4-5) ◽  
pp. 53-61 ◽  
Author(s):  
P. B. Birch ◽  
G. G. Forbes ◽  
N. J. Schofield
Keyword(s):  
Management Practices ◽  
Major Change ◽  
High Flow ◽  
Catchment Management ◽  
Flow Rates ◽  
Early Results ◽  
Phosphorus Loads ◽  
Time Of Year ◽  
High Runoff

Early results from monitoring runoff suggest that the programme to reduce application of superphosphate to farmlands in surrounding catchments has been successful in reducing input of phosphorus to the eutrophic Peel-Harvey estuary. In the estuary this phosphorus fertilizes algae which grow in abundance and accumulate and pollute once clean beaches. The success of the programme has been judged from application of an empirical statistical model, which was derived from 6 years of data from the Harvey Estuary catchment prior to a major change in fertilizer practices in 1984. The model relates concentration of phosphorus with rate of flow and time of year. High phosphorus concentrations were associated with high flow rates and with flows early in the high runoff season (May-July). The model predicted that the distribution of flows in 1984 should have resulted in a flow-weighted concentration of phosphorus near the long-term average; the observed concentration was 25% below the long-term average. This means that the amount of phosphorus discharged into the Harvey Estuary could have been about 2 5% less than expected from the volume of runoff which occurred. However several more years of data are required to confirm this trend.

scholarly journals ‘Tanned’ gelatin spheres and granules for exclusion chromatography

1968 ◽  
Vol 108 (4) ◽  
pp. 641-646 ◽  
Author(s):  
A. Polson ◽  
W. Katz
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
High Molecular Weight ◽  
Weight Fraction ◽  
High Flow ◽  
High Molecular Weight Fraction ◽  
Flow Rates ◽  
Protein Molecules ◽  
Exclusion Chromatography

1. The preparation of tanned gelatin spheres and granules from high-molecular-weight gelatin is described. This material is comparatively hard, giving high flow rates, is insoluble in water at temperatures between 0° and 100° and is resistant to digestion by trypsin and chymotrypsin. The high-molecular-weight fraction of gelatin was prepared by precipitation with polyethylene glycol, and the spheres and granules prepared from this fraction were hardened and insolubilized by tanning with either formalin or chromium salts or both. 2. The spheres and granules were used successfully for the separation of protein molecules and other protein-aceous materials ranging in molecular weight from 200 to greater than 6000000. This gel exclusion material has several properties superior to those of other products used for similar purposes. Further, it was noticed that the porosity of the spheres differed considerably from that of the granules.

scholarly journals Evaluation of a Humidified Nasal High-Flow Oxygen System, Using Oxygraphy, Capnography and Measurement of Upper Airway Pressures

2011 ◽  
Vol 39 (6) ◽  
pp. 1103-1110 ◽  
Author(s):  
J. E. Ritchie ◽  
A. B. Williams ◽  
C. Gerard ◽  
H. Hockey
Keyword(s):  
Healthy Volunteers ◽  
Airway Pressure ◽  
Gas Flow ◽  
Air Entrainment ◽  
High Flow ◽  
Positive Pressure ◽  
Mean Airway Pressure ◽  
Flow Rates ◽  
Oxygen Fraction ◽  
Airway Pressures

In this study, we evaluated the performance of a humidified nasal high-flow system (Optiflow™, Fisher and Paykel Healthcare) by measuring delivered FiO2 and airway pressures. Oxygraphy, capnography and measurement of airway pressures were performed through a hypopharyngeal catheter in healthy volunteers receiving Optiflow™ humidified nasal high flow therapy at rest and with exercise. The study was conducted in a non-clinical experimental setting. Ten healthy volunteers completed the study after giving informed written consent. Participants received a delivered oxygen fraction of 0.60 with gas flow rates of 10, 20, 30, 40 and 50 l/minute in random order. FiO2, FEO2, FECO2 and airway pressures were measured. Calculation of FiO2 from FEO2 and FECO2 was later performed. Calculated FiO2 approached 0.60 as gas flow rates increased above 30 l/minute during nose breathing at rest. High peak inspiratory flow rates with exercise were associated with increased air entrainment. Hypopharyngeal pressure increased with increasing delivered gas flow rate. At 50 l/minute the system delivered a mean airway pressure of up to 7.1 cmH2O. We believe that the high gas flow rates delivered by this system enable an accurate inspired oxygen fraction to be delivered. The positive mean airway pressure created by the high flow increases the efficacy of this system and may serve as a bridge to formal positive pressure systems.

Thermal Hydraulic, Exergy and Exergy-Economic Analysis of Micro Heat Sinks at High Flow Rates

2010 ◽  
Author(s):  
Mehmed Rafet O¨zdemir ◽  
Ali Kos¸ar ◽  
Orc¸un Demir ◽  
Cemre O¨zenel ◽  
Og˘uzhan Bahc¸ivan
Keyword(s):  
High Flow ◽  
Heat Sinks ◽  
Flow Rates ◽  
Geometrical Properties ◽  
Pin Fin ◽  
Fluidic Devices ◽  
System Flow ◽  
Reaction Chambers ◽  
Heat And Fluid Flow ◽  
Microchannel Device

Recently, micro/nanofabrication technology has been used to develop a number of microfluidic systems. With its integration to microfluidic devices, microchannels and micro scale pin fin heat sinks find applications in many areas such as drug delivery and propulsion in biochemical reaction chambers and micro mixing. Many research efforts have been performed to reveal thermal and hydrodynamic performances of microchannel based micro fluidic devices. In the current study, it is aimed to extend the knowledge on this field by investigating heat and fluid flow in micro heat sinks at high flow rates. Moreover, thermodynamic and thermo-economic aspects were also considered. De-ionized water was used as the coolant in the system. Flow rates were measured over pressures of 20–80 psi. A serpentine heater was deposited at the back of the micro pin fin devices to enable the delivery of heat to these devices. Two micro-pin fin devices each having different geometrical properties (Circular based and Hydrofoil based) were used in this study. In addition, the performances (thermal-hydraulic, exergy, exergo-economic) were also experimentally obtained for a plain microchannel device. Thermal resistances, exergy efficiencies and thermo-economic parameters were obtained from the devices and their performances were assessed.

scholarly journals 2P034 High-speed AFM observation of structure and function of MukB(01B. Protein: Structure & Function,Poster,The 52nd Annual Meeting of the Biophysical Society of Japan(BSJ2014))

2014 ◽  
Vol 54 (supplement1-2) ◽  
pp. S200
Author(s):  
Kenta Yagi ◽  
Koichi Yano ◽  
Noriyuki Kodera ◽  
Hironori Niki ◽  
Toshio Ando
Keyword(s):  
Protein Structure ◽  
Structure Function ◽  
Annual Meeting ◽  
High Speed ◽  
Structure And Function ◽  
Biophysical Society ◽  
And Function ◽  
Afm Observation

scholarly journals Tunable Wide-Angle Tunneling in Graphene-Assisted Frustrated Total Internal Reflection

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Thang Q. Tran ◽  
Sangjun Lee ◽  
Hyungjun Heo ◽  
Sangin Kim
Keyword(s):  
Total Internal Reflection ◽  
Internal Reflection ◽  
Wide Angle ◽  
Frustrated Total Internal Reflection

Experimental Investigation of Pressure Fluctuations on Inner Wall of a Centrifugal Pump

2019 ◽  
Vol 36 (4) ◽  
pp. 401-410 ◽  
Author(s):  
Xiao-Qi Jia ◽  
Bao-Ling Cui ◽  
Zu-Chao Zhu ◽  
Yu-Liang Zhang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Pressure Fluctuations ◽  
High Flow ◽  
Low Flow ◽  
Centrifugal Pumps ◽  
Flow Rates ◽  
Pressure Distributions ◽  
Blade Passing Frequency

Abstract Affected by rotor–stator interaction and unstable inner flow, asymmetric pressure distributions and pressure fluctuations cannot be avoided in centrifugal pumps. To study the pressure distributions on volute and front casing walls, dynamic pressure tests are carried out on a centrifugal pump. Frequency spectrum analysis of pressure fluctuation is presented based on Fast Fourier transform and steady pressure distribution is obtained based on time-average method. The results show that amplitudes of pressure fluctuation and blade-passing frequency are sensitive to the flow rate. At low flow rates, high-pressure region and large pressure gradients near the volute tongue are observed, and the main factors contributing to the pressure fluctuation are fluctuations in blade-passing frequency and high-frequency fluctuations. By contrast, at high flow rates, fluctuations of rotating-frequency and low frequencies are the main contributors to pressure fluctuation. Moreover, at low flow rates, pressure near volute tongue increases rapidly at first and thereafter increases slowly, whereas at high flow rates, pressure decreases sharply. Asymmetries are observed in the pressure distributions on both volute and front casing walls. With increasing of flow rate, both asymmetries in the pressure distributions and magnitude of the pressure decrease.

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