scholarly journals Pressure and Water Flow Patterns in the Respiratory Tract of the Bass (Micropterus Salmoides)

1984 ◽  
Vol 113 (1) ◽  
pp. 151-164 ◽  
Author(s):  
GEORGE V. LAUDER
Keyword(s):  
Respiratory Tract ◽  
Flow Velocity ◽  
Buccal Cavity ◽  
Micropterus Salmoides ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
Wave Form ◽  
Dimensional Changes ◽  
Velocity Wave ◽  
Phase Differences

Instantaneous water velocities in the respiratory tract of bass, Micropterus salmoides (Lacepéde), were measured using a fast-responding hot-filmanemometer. The flow velocity wave form varied within the buccal cavity, with lower peak velocities at the back than at the front. Flow velocity in both the buccal and opercular cavities varied over the respiratory cycle, and 80% of signal power in the velocity wave form was between 1 and 10 Hz. Flow within the buccal cavity reached a maximum velocity of 50cms−1 and did not decline to zero, even when differential pressure across the gills was negative. Simultaneous measurement of dimensional changes in the branchial apparatus, pressure and velocity fluctuations showed that gill bar adduction coincides both with the pressure reversal across the gills and with maximum flow velocities in the opercular cavity. The movement of the gillbars during respiration causes flow velocity fluctuation just in front of the primary lamellae and may be an important component of intraoral resistance contributing to the phase differences between pressure and velocity waveforms.

scholarly journals PENGARUH PILAR JEMBATAN PANGO TERHADAP POLA ALIRAN SUNGAI KRUENG ACEH

2018 ◽  
Vol 1 (4) ◽  
pp. 1005-1018
Author(s):  
Teuku Devansyah Putra ◽  
Eldina Fatimah ◽  
Azmeri Azmeri
Keyword(s):  
Flow Velocity ◽  
Flow Pattern ◽  
Cross Section ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
Surface Water Modeling ◽  
River Cross Section ◽  
Maximum Flow Velocity ◽  
Banda Aceh ◽  
River Bend

Abstract: Pango Fly Over is located in the coordinate of 50 32' 07.32" LU (North Latitude) and 950 20' 52.90” BT (East Longitude) on Pango Village, Ulee Kareng Sub District, Banda Aceh. This bridge was built across Krueng Aceh River and the pillars were built in the river so that it narrows the river cross section and affecting the increasing of flow velocity. From the research location observation, it is found that the bridge pillars cause the more narrowing of the river cross section and there is the damage of the riverbank around the river bend located in the downstream of the pillars. If there is no further follow up, it will erode the national road. This research aims to find out flow pattern without and with the pillars, and to know the flow pattern behavior in the river bend. This research uses Surface Water Modeling System (SMS Version 11.2) Program. The length of the river reviewed is ± 500 meters. The flow discharge used in this research is the flood discharge which the period is Q – 100 and the value is 627.74 m³/second (passing the Pango Fly Over). From the result of the flow patter simulations, it is obtained that the maximum flow velocity without the pillars found in the middle location of V3 reviewed point on the distance 45 m from the riverbank is 0.45 m/sec and maximum flow velocity with the pillars found in the middle location of V3 reviewed point on the distance 33 m from the riverbank is 0.35/sec. In the outer bend of the flow pattern simulation result without pillars, it is obtained that the maximum velocity found in V6 reviewd location on the distance 50 m is 0.83 m/sec in the left side of the flow.Meanwhile in the downstream of the bend, the maximum velocity wit the bridge pillars found in V6 reviewd location on the distance 50 m is 0.95 m/det in the left side of the flow. In the bridge pillars downstream location, there is the river bend required the riverbank reinforcement and the riverbed reinforcement in order to avoid the erosion in the riverbank, because it will endanger the public facilities. Abstrak: Jembatan fly over Pango berada pada koordinat  50 32' 07.32" LU dan 950 20' 52.90” BT terletak di desa Pango Kecamatan Ulee Kareng kota Banda Aceh. Jembatan ini di bangun melintang Sungai Krueng Aceh dan pilar jembatan dibangun pada sungai sehingga terjadi penyempitan penampang sungai yang menyebabkan kecepatan aliran bertambah, Dari tinjauan lokasi penelitian pilar jembatan semakin mengalami penyempitan penampang sungai dan terjadi kerusakan tebing di sekitar belokan sungai yang berada di hilir jembatan. Bila tidak segera di tindak lanjuti akan berdampak tergerusnya jalan nasional. Penelitian ini bertujuan untuk mengetahui pola aliran tanpa adanya pilar dengan adanya pilar serta untuk mengetahui perilaku pola aliran yang terjadi pada belokan sungai. Penelitian ini menggunakan program Surfacewater Modeling System (SMS. Versi 11.2). Panjang sungai yang di tinjau ± 500 meter. Debit aliran yang digunakan pada penelitian ini mengunakan debit banjir periode ulang Q-100 tahunan yaitu 627,74 m³/detik (yang melewati jembatan fly over Pango). Dari hasil simulasi pola aliran didapatkan besaran kecepatan aliran tanpa pilar pada lokasi tengah aliran pada titik tinjauan V3 dengan jarak 45 m dari tanggul sungai kecepatan maksimumnya 0,45 m/det dan besaran kecepatan aliran dengan adanya pilar jembatan pada lokasi tengah pilar pada titik tinjauan V3 dengan jarak 33 m dari tanggul sungai kecepatan maksimumnya 0,35 m/det. Pada belokan luar dari hasil simulasi kecepatan aliran tanpa pilar besaran kecepatan maksimum pada titik tinjau V6 dengan jarak 50 m yaitu 0,83 m/det pada kiri aliran. Sedangkan di hilir belokan pada titik tinjau V6 dengan jarak 50 m dengan adanya pilar jembatan besaran kecepatan maksimum yaitu 0,95 m/det kiri aliran. Pada hilir pilar jembatan terdapat belokan sungai yang memerlukan perkuatan tebing dan perkuatan dasar agar tidak terjadi erosi di tebing sungai, sebab hal ini dapat membahayakan terhadap fasilitas umum.

Banding of the pulmonary trunk in preparation for a Fontan operation

1999 ◽  
Vol 9 (1) ◽  
pp. 49-54
Author(s):  
Takahiko Sakamoto ◽  
Yorikazu Harada ◽  
Takamasa Takeuchi ◽  
Katsumasa Morishima ◽  
Gengi Satomi ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Fontan Operation ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
Pulmonary Trunk ◽  
Trunk Length ◽  
Pulmonary Flow ◽  
Pulmonary Arterial ◽  
Maximum Flow Velocity ◽  
Aorta Diameter

AbstractBanding of the pulmonary trunk is an important surgical procedure for patients who have con genital cardiac malformations with unrestricted pulmonary flow. We propose a new concept for determining in such circumstances the most appropriate length of the band used to constrict the pulmonary trunk in preparation for a Fontan operation. We studied 14 patients undergoing banding of the pulmonary trunk and measured the following parameters: diameter of aorta, diameter of pulmonary trunk, length of pulmonary arterial band and maximum flow velocity across the banded segment. We calculated an index from our orig inal parameter based on the formula; length of band/(diameter of aorta diameter of pulmonary trunk). The diameter of aorta was 9.5 ± 1.4 mm, and that of the pulmonary trunk was 9.6 ± 2.3 mm. The length of the band was 16.5 ± 3.4 mm, giving a calculated index of 0.188 ± 0.038. The maximum flow velocity was 4.02 ± 0.46 m/s. No correlation was found between the length of the band and body weight, and also no correlation was found between the length of the band and maximum flow velocity. The calculated index had a negative correlation with the maximum velocity of flow across the band (y = -8.13x + 5.56, R = 0.74, p < 0.01). We believe that the proposed index is a useful guide in determining the length of a pulmonary band when preparing patients for a Fontan operation.

Carotid Artery Atherosclerotic Disease Assessed by Flow Velocity Wave Form Analysis in Hemodialyzed Normotensive and Hypertensive Patients

Nephron ◽  
1986 ◽  
Vol 44 (3) ◽  
pp. 180-185 ◽  
Author(s):  
Daniele Bernardi ◽  
Andrea Ferreri ◽  
Policarpo Moretti ◽  
Elisa Nesti ◽  
Donato Antonio Urti ◽  
...  
Keyword(s):  
Carotid Artery ◽  
Flow Velocity ◽  
Atherosclerotic Disease ◽  
Wave Form ◽  
Hypertensive Patients ◽  
Form Analysis ◽  
Velocity Wave

The Effect of Frequency on the Flow and Particle Collection Patterns under Electroosmosis

2014 ◽  
Vol 605 ◽  
pp. 59-62
Author(s):  
Che Hung Wei ◽  
Lin Chi Wu
Keyword(s):  
Flow Velocity ◽  
Bottom Electrode ◽  
Low Frequency ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
Ac Electroosmosis ◽  
Particle Collection ◽  
Modified Polystyrene ◽  
Maximum Flow Velocity

The collection and manipulation of small objects is important in bioassays. One commonly used force to manipulate small objects is electroosmosis which has the advantages of easy fabrication and small power consumption. Many factors affect the electroosmosis like surface charge density, applied voltage and frequency. For ac electroosmosis, frequency affects flow pattern and particle collection. In this study, the role of frequency is investigated by experiments and verified by numerical simulation. The electroosmosis collecting chip is made of two parallel electrodes separated by a spacer. The chip consists of a top ITO electrode and a bottom electrode made by Corning 1737 glass with different patterned sputtered Cr electrode. The spinning photoresist on the bottom electrode is used as dielectric layer and the electrodes are separated by a curing PDMS spacer. The amine-modified polystyrene particles were collected by varying frequency. To further investigate the mechanism, numerical simulations were carried out using commercial software Comsol with multi-physics setting. The results show the particle flow and collection pattern is sensitive to frequency. For low frequency 100 Hz, the maximum flow velocity occurred in the peripheral boundary of the bottom electrode and the particles are depleted in the central and accumulated in the peripheral area. For high frequency 1000 Hz, the particles are accumulated in the center region of the bottom electrode where the maximum velocity occurs. From simulation, the maximum flow velocity occurs from the boundary towards the center as frequency increases. Meanwhile, the magnitude of the maximum flow velocity is also proportional to the applied frequency. For particles collected by electroosmosis, varying frequency will result in different flow and collection pattern.

Umbilical artery doppler flow velocity wave form analysis and the outcome of hypertensive pregnancies

1988 ◽  
Vol 9 (1) ◽  
pp. 9-13 ◽  
Author(s):  
N. G. Haddad ◽  
F. D. Johnstone ◽  
S. E. Chambers ◽  
P. R. Hoskins ◽  
W. N. McDicken
Keyword(s):  
Flow Velocity ◽  
Umbilical Artery ◽  
Wave Form ◽  
Form Analysis ◽  
Doppler Flow ◽  
Velocity Wave ◽  
Umbilical Artery Doppler

scholarly journals An Experimental Study on the Influence of Drastically Varying Discharge Ratios on Bed Topography and Flow Structure at Urban Channel Confluences

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1147
Author(s):  
Zhiyuan Zhang ◽  
Yuqing Lin
Keyword(s):  
Transition Period ◽  
Maximum Velocity ◽  
Maximum Flow ◽  
River Network ◽  
Morphological Alteration ◽  
Minor Role ◽  
Material Transport ◽  
Lateral Velocity ◽  
Basic Work ◽  
Discharge Ratio

The confluences of rivers are important nodes for energy conversion and material transport in the river network. A slight morphological alteration of the confluences may trigger the “butterfly effect”, which will bring about changes in the ecology and environment of the entire river network. During the transition period of the wet and dry seasons, the variation of discharge ratio will make the originally balanced river bed change again, which will bring a series of follow-up effects. This research mainly studied the features of water flow itself and results showed that the variation of discharge ratio caused secondary erosion of the balanced bed surface and transported the sediment downstream. Thus, the zone of maximum velocity was enlarged and the maximum flow velocity at the equal discharge was reduced, and more intense vortex and turbulence were generated. The lateral velocity, vertical velocity, and turbulent structure were mainly controlled by the quantity and ratio of the discharge, and the varying topography only played a minor role in local areas. Nowadays, some scholars have been studying the combination of flow field features and various environmental substances and biological habitats, and the basic work done in this article has laid the foundation for these studies.

Vibratory Feeding by Nonsinusoidal Vibration—Optimum Wave Form

1985 ◽  
Vol 107 (2) ◽  
pp. 188-195 ◽  
Author(s):  
S. Okabe ◽  
Y. Kamiya ◽  
K. Tsujikado ◽  
Y. Yokoyama
Keyword(s):  
Experimental Results ◽  
Wave Form ◽  
Velocity Wave ◽  
The Mean ◽  
Straight Lines ◽  
Vibratory Conveyor ◽  
Theoretical Results ◽  
Vibratory Feeding

This paper presents the conveying velocity on a vibratory conveyor whose track is vibrated by nonsinusoidal vibration. The velocity wave form of the vibrating track is approximated by six straight lines, and five distortion factors of the wave form are defined. Considering the modes of motion of the particle, the mean conveying velocity is calculated for various conditions. Referring to these results, the optimum wave form is clarified analytically. The theoretical results show that the mean conveying velocity is considerably larger than that of ordinary feeders if the proper conveying conditions are chosen. The theoretical results are confirmed by experimental results.

scholarly journals The mechanical origin of snow avalanche dynamics and flow regime transitions

2020 ◽  
Author(s):  
Xingyue Li ◽  
Betty Sovilla ◽  
Chenfanfu Jiang ◽  
Johan Gaume
Keyword(s):  
Flow Velocity ◽  
Alpha Angle ◽  
Maximum Flow ◽  
Flow Regimes ◽  
Snow Avalanche ◽  
Snow Avalanches ◽  
Deposition Zone ◽  
Avalanche Dynamics ◽  
Maximum Flow Velocity ◽  
Deposit Height

Abstract. Snow avalanches cause fatalities and economic damages. Key to their mitigation entails the understanding of snow avalanche dynamics. This study investigates the dynamic behaviors of snow avalanches, using the Material Point Method (MPM) and an elastoplastic constitutive law for porous cohesive materials. By virtue of the hybrid Eulerian-Lagrangian nature of MPM, we can handle processes involving large deformations, collisions and fractures. Meanwhile, the elastoplastic model enables us to capture the mixed-mode failure of snow, including tensile, shear and compressive failure. Using the proposed numerical approach, distinct behaviors of snow avalanches, from fluid-like to solid-like, are examined with varied snow mechanical properties. In particular, four flow regimes reported from real observations are identified, namely, cold dense, warm shear, warm plug and sliding slab regimes. Moreover, notable surges and roll-waves are observed peculiarly for flows in transition from cold dense to warm shear regimes. Each of the flow regimes shows unique flow characteristics in terms of the evolution of the avalanche front, the free surface shape, and the vertical velocity profile. We further explore the influence of slope geometry on the behaviors of snow avalanches, including the effect of slope angle and path length on the maximum flow velocity, the $\\alpha$ angle and the deposit height. Unified trends are obtained between the normalized maximum flow velocity and the scaled $\\alpha$ angle as well as the scaled deposit height, reflecting analogous rules with different geometry conditions of the slope. It is found the maximum flow velocity is mainly controlled by the friction between the bed and the flow, the geometry of the slope, and the snow properties. In addition to the flow behavior before reaching the deposition zone, which has long been regarded as the key factor governing the $\\alpha$ angle, we reveal the crucial effect of the stopping behavior in the deposition zone. Furthermore, our MPM model is benchmarked with simulations of real snow avalanches. The evolution of the avalanche front position and velocity from the MPM modeling shows reasonable agreement with the measurement data from literature. The MPM approach serves as a novel and promising tool to offer systematic and quantitative analysis for mitigation of gravitational hazards like snow avalanches.

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