Assessing Hydrodynamic Separators under High Water Flow Conditions

2009 ◽  
Author(s):  
David Saddoris ◽  
Omid Mohseni ◽  
John Gulliver
Keyword(s):  
Water Flow ◽  
High Water ◽  
Flow Conditions

scholarly journals Water balance of selected floodplain lake basins in the Middle Bug River valley

2013 ◽  
Vol 10 (8) ◽  
pp. 10061-10082 ◽  
Author(s):  
J. Dawidek ◽  
B. Ferencz
Keyword(s):  
Water Balance ◽  
Water Flow ◽  
Radical Change ◽  
High Water ◽  
River Channel ◽  
Floodplain Lake ◽  
Flow Conditions ◽  
Water Balance Components ◽  
Catchment Areas ◽  
Lake Basins

Abstract. This study is the first attempt in the literature on the subject of comparing water balance equations for floodplain lake basins depending on the type of connection the lake has to its parent river. Where confluent lakes (upstream connections) were concerned, it was only possible to apply a classic water balance equation. When dealing with contrafluent lakes (downstream connections) as well as lakes with a complex recharge type (contrafluent–confluent) modified equations were created. The hydrological type of a lake is decided by high water flow conditions and, consequently, the duration of potamophase (connection with a river) and limnophase (the isolation of the lake), which determine the values of particular components and the proportion of the vertical to horizontal water exchange rate. Confluent lakes are characterised by the highest proportion of horizontal components (the inflow and runoff of river water) to the vertical ones (precipitation and evaporation). The smallest differences occur with respect to a contrafluent lake. In the case of confluent lakes, the relationship between water balance components resulted from the consequent water flow through the basin, consistent with the slope of the river channel and valley. The supplying channels of contrafluent lakes had an obsequent character, which is why the flow rate was lower. Lakes with a complex, contrafluent–confluent recharge type showed intermediate features. After a period of slow contrafluent recharge, the inflow of water through a downstream crevasse from the area of the headwater of the river was activated; this caused a radical change of flow conditions into confluent ones. The conditions of water retention in lake basins were also varied. Apart from hydrological recharge, also the orographic features of the catchment areas of the lakes played an important role here, for example, the distance from the river channel, the altitude at which a given catchment was located within the floodplain and the complexity of the channels of fluvial-water inflow.

scholarly journals Hydrodynamics of an in-pond raceway system with an aeration plug-flow device for application in aquaculture: an experimental study

2019 ◽  
Vol 6 (7) ◽  
pp. 182061 ◽  
Author(s):  
Wuhua Li ◽  
Xiangju Cheng ◽  
Jun Xie ◽  
Zhaoli Wang ◽  
Deguang Yu
Keyword(s):  
Water Flow ◽  
Plug Flow ◽  
Experimental Studies ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
High Water ◽  
Secondary Flows ◽  
Commercial Application ◽  
Flow Device ◽  
Intensive Aquaculture

An in-pond raceway system (IPRS) is an effective intensive aquaculture practice for regions with high water consumption and limited land resources. Water flow and dissolved oxygen (DO) are important for sustainable aquaculture. Several innovations have been made in IPRS design and operation to increase water exchange and DO concentration; one of these is the aeration plug-flow device (APFD). The APFD is commonly used in China as the only power source for water recirculation in aquaculture ponds. Understanding of the hydrodynamics of the system is necessary to improve the design of the IPRS with APFD. To this end, we performed experimental studies on a model system. We measured three-dimensional velocity at various locations using an Acoustic Doppler Velocimeter. Velocity distribution and turbulence characteristics were assessed, and plug-flow characteristics were analysed. Two patterns of velocity and turbulence in horizontal sections were observed: near the APFD, the water flow was intensively pushed downstream and simultaneously recirculated; farther away, the reflux area gradually decreased and the velocity and turbulence distribution trended towards uniform. Secondary flows occurred in different directions, which improved the diffusion of materials and DO retention. The system is effectively self-circulating, and the plug-flow capability may be scaled up for commercial application.

Fluid Absorption in the Kidney Proximal Tubule

Physiology ◽  
1987 ◽  
Vol 2 (1) ◽  
pp. 22-26
Author(s):  
JA Schafer
Keyword(s):  
Proximal Tubule ◽  
Water Flow ◽  
Water Permeability ◽  
Interstitial Fluid ◽  
High Water ◽  
Fluid Absorption ◽  
Humoral Factors ◽  
Solute Absorption ◽  
Leaky Epithelium

Fluid absorption in the proximal tubule can be driven by a small osmotic difference between the luminal and interstitial fluids because this leaky epithelium has a high water permeability. The osmotic difference is produced by solute absorption, which tends to dilute the luminal fluid and concentrate the interstitial fluid. However, important questions remain unanswered regarding the pathway for water flow and the role of hemodynamic and humoral factors.

Mobility of Herbicides in Soil Columns Under Saturated- and Unsaturated-Flow Conditions

Weed Science ◽  
1982 ◽  
Vol 30 (6) ◽  
pp. 579-584 ◽  
Author(s):  
Jerome B. Weber ◽  
David M. Whitacre
Keyword(s):  
Unsaturated Flow ◽  
Sandy Loam ◽  
High Water ◽  
Loamy Sand ◽  
Silt Loam ◽  
Flow Conditions ◽  
Soil Columns ◽  
Saturated Flow

Under unsaturated-flow conditions, bromacil (5-bromo-3-sec-butyl-6-methyluracil) was considerably more mobile than buthidazole {3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxyl-1-methyl-2-imidazolidinone}. Because of their high water solubilities, both herbicides were much more mobile than atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine), prometon [2,4-bis (isopropylamino)-6-methoxy-s-triazine], or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea]. Under saturated-flow conditions, buthidazole was leached through Lakeland loamy sand in slightly greater amounts than tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea} or CN-10-3510 (formerly VEL 3510) {1-β,β-dimethoxyl-1-methyl-3-[5-(1,1-dimethylethyl)-1,3, 4-thiadiazol-2-yl] urea}. Distribution of the three herbicides in the leached soil was similar and relatively uniform. In Lakeland loamy sand, 30 times as much tebuthiuron was leached under saturated-flow conditions as under unsaturated-flow conditions. Intermittent saturated-unsaturated-flow conditions resulted in four times as much leaching of tebuthiuron as unsaturated flow alone. Only one-tenth as much tebuthiuron leached under intermittent saturated-unsaturated-flow conditions as under saturated-flow conditions. Tebuthiuron added to Lakeland soil and oven-dried was retained in significantly greater amounts than when added to moist Lakeland soil. Low amounts of tebuthiuron leached through Lakeland loamy sand, Portsmouth sandy loam, and Rains silt loam, but high amounts leached through Davidson clay. Greater amounts of the herbicide were retained in the surface zones of the three former soils, but the inverse was the case for the Davidson soil.

Reconstitution of water channel function of aquaporins 1 and 2 by expression in yeast secretory vesicles

1998 ◽  
Vol 274 (1) ◽  
pp. F34-F42 ◽  
Author(s):  
Larry A. Coury ◽  
John C. Mathai ◽  
G. V. Ramesh Prasad ◽  
Jeffrey L. Brodsky ◽  
Peter Agre ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Water Flow ◽  
Water Channel ◽  
Immunoblot Analysis ◽  
High Water ◽  
Activation Energies ◽  
Secretory Vesicles ◽  
Channel Function ◽  
Other Substances

Aquaporins 1 (AQP1) and 2 (AQP2) were expressed in the yeast secretory mutant sec6-4. The mutant accumulates post-Golgi, plasma membrane-targeted vesicles and may be used to produce large quantities of membrane proteins. AQP1 or AQP2 were inducibly expressed in yeast and were localized within isolated sec6-4 vesicles by immunoblot analysis. Secretory vesicles containing AQP1 and AQP2 exhibited high water permeabilities and low activation energies for water flow, indicating expression of functional AQP1 and AQP2. AQP1 solubilized from secretory vesicles was successfully reconstituted into proteoliposomes, demonstrating the ability to use the yeast system to express aquaporins for reconstitution studies. The AQP2-containing secretory vesicles showed no increased permeability toward formamide, urea, glycerol, or protons compared with control vesicles, demonstrating that AQP2 is highly selective for water over these other substances. We conclude that the expression of aquaporins in yeast sec6 vesicles is a valid system to further study mammalian water channel function.

Roles of clay layers in rainfall-runoff processes in a serpentinite headwater catchment

2020 ◽  
Author(s):  
Takahiko Yoshino ◽  
Shin'ya Katsura
Keyword(s):  
Water Flow ◽  
Groundwater Level ◽  
Mineral Soil ◽  
High Water ◽  
Organic Soil ◽  
Rainfall Runoff ◽  
Soil Layers ◽  
Clay Layers ◽  
Headwater Catchment

<p>Rainfall-runoff processes in a headwater catchment have been typically explained by water flow in permeable soil layers (comprised of organic soil layers and mineral soil layers produced by weathering of bedrock) overlying less permeable layers (i.e., bedrock). In a catchment where mineral soils are characterized by clayey materials (e.g., mudstone, slate, and serpentine catchment), it is possible that mineral soil layers function substantially as less permeable layers because of a low permeability of clayey materials. However, roles of clay layers in rainfall-runoff processes in such a headwater catchment are not fully understood. In this study, we conducted detailed hydrological, hydrochemical, and thermal observations in a serpentinite headwater catchment (2.12 ha) in Hokkaido, Northern Japan, where mineral soil layers consisting of thick clay layers (thickness: approximately 1.5 m) produced by weathering of the serpentinite bedrock underlies organic soil layers (thickness: approximately 0.4 m). Saturated hydraulic conductivity (Ks) and water retention curve of these two layers were also measured in a laboratory. The observation results demonstrated that groundwater was formed perennially in the organic soil layers and clay layers. The groundwater level within the organic soil layers and specific discharge of the catchment showed rapid and flashy change in response to rainfall. In contrast, the groundwater level within the clay layers showed slow and small change. Temperature of the groundwater and stream water suggested that water from the depth of the organic soil layers contributed to streamflow. The electric conductivity (EC) of the groundwater in the clay layers was very high, ranging from 321 to 380 µS cmˉ¹. On the other hand, the EC of soil water (unsaturated water stored in the organic soil layers) was relatively low, ranging from 98 to 214 µS cmˉ¹. Hydrograph separation using EC showed that contribution of water emerging from the clay layers to the total streamflow ranged from 31 to 76% in low to high flow periods. Temporal variation in the total head, measured using tensiometers installed at four depths at the ridge of the catchment, indicated that in wet periods when the groundwater level in the organic soil layers was high, water flow from the organic soil layers to the clay layers occurred, whereas, in dry periods, water flow from the clay layers into the organic soil layers occurred. The laboratory measurements showed that the organic soil layers had high Ks (10ˉ² cm sˉ¹) and low water-holding capacity, whereas the clay layers had low Ks (10ˉ⁴ cm sˉ¹) and high water-holding capacity. It can be concluded from these results that clay layers play two roles: (1) forming perched groundwater table and lateral flow on the clay layers (the role of less permeable layers) and (2) supplying water into the organic soil layers in the dry periods (the role of water supplier).</p>

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