Field Investigation of Compost Blankets for Erosion Control under Concentrated Flow Conditions

2009 ◽  
Vol 52 (1) ◽  
pp. 81-91 ◽  
Author(s):  
X. Zhu ◽  
L. M. Risse
Keyword(s):  
Erosion Control ◽  
Field Investigation ◽  
Flow Conditions ◽  
Concentrated Flow

scholarly journals Estimation of energy dissipation in step-pool reaches of mountain river - a field investigation

2021 ◽  
Author(s):  
Abbas Torabizadeh ◽  
Hamid-Reza Ghafouri ◽  
Mohamadreza Majdzadehtabatabai ◽  
Ahmad Tahershamsi
Keyword(s):  
Energy Dissipation ◽  
Field Measurements ◽  
Step Length ◽  
Field Investigation ◽  
Mountain River ◽  
Mountainous Areas ◽  
Flow Conditions ◽  
Effective Parameters ◽  
Mountain Rivers ◽  
Height Difference

The bed of the step-pool rivers is adapted to the flow conditions in terms of the topographic position and the steep slope of the path in such a way to dissipate the water energy, along the river. The beds of these rivers is sinusoidal like the meander rivers. However, as the river banks are mostly rocky in mountainous areas and the erosion in these areas is less, the bed fluctuation of these reaches is mainly vertical. When the water flow streams from the step crest into the pool, most of the water energy dissipates. In addition to the height difference, other factors contribute to the energy dissipation in the step pool reaches. The present study examines the energy dissipation by determining its effective factors, including step height (H), step length (L), hydraulic radius (R), sediment material diameter (d84), velocity in the step (V), etc. by field measurements in three reaches of mountain rivers. In the same vein, an equation is provided to estimate energy dissipation in the step pool reaches, by considering measurable effective parameters.

Laboratory Investigation of Rill Erosion on Compost Blankets under Concentrated Flow Conditions

2010 ◽  
Vol 53 (4) ◽  
pp. 1077-1086
Author(s):  
X. Zhu ◽  
L. M. Risse ◽  
S. C. McCutcheon ◽  
E. W. Tollner ◽  
T. C. Rasmussen ◽  
...  
Keyword(s):  
Laboratory Investigation ◽  
Rill Erosion ◽  
Flow Conditions ◽  
Concentrated Flow

Paper 31: An Experiment on Erosion Control, Using a 60-Mw Steam Turbine

1967 ◽  
Vol 182 (8) ◽  
pp. 297-308 ◽  
Author(s):  
K. W. Todd ◽  
B. Gregory
Keyword(s):  
Field Study ◽  
Steam Turbine ◽  
Erosion Control ◽  
Water Extraction ◽  
Wet Steam ◽  
Flow Conditions ◽  
Erosion Rates ◽  
Laboratory Conditions ◽  
Trailing Edges ◽  
Last Stage

A twin-exhaust steam turbine of 60-MW output was used for a field study of a method of wet steam erosion control which had been examined previously under laboratory conditions. The last stage of one exhaust was modified so that measured quantities of steam and water could be extracted, or steam injected through slots in the trailing edges of the diaphragm blades. Variations in erosion rates of the last-stage moving blades in both exhausts were compared by recording continuously the changes in emissivity of radio-active labels attached to sample blades. An introscope was used to study flow conditions during the experiment, and after some five months' operation the set was opened up for inspection, which confirmed the estimates that water extraction reduced erosion by a factor of 5.

Field evaluation of sediment retention devices under concentrated flow conditions

2015 ◽  
Vol 15 (9) ◽  
pp. 2022-2031 ◽  
Author(s):  
Carlos Bulnes García ◽  
Joseph Monical ◽  
Rabin Bhattarai ◽  
Prasanta K. Kalita
Keyword(s):  
Field Evaluation ◽  
Flow Conditions ◽  
Sediment Retention ◽  
Concentrated Flow

scholarly journals Estimating Optimal Geotextile Type for Controlling Soil Erosion

2019 ◽  
Vol 8 (10) ◽  
pp. 1439-1442
Keyword(s):  
Soil Erosion ◽  
Laminar Flow ◽  
Erosion Control ◽  
Control Soil ◽  
Flow Conditions ◽  
Hydraulic Gradients ◽  
Control Erosion ◽  
Laminar Flow Conditions

One of the major functions of geotextiles is to control soil erosion. Apparent opening size and permeability of non-woven geotextiles are properties that control erosion. In this manuscript, soil taken from an eroded pond is considered for the study. Filtration and clogging behavior of the several geotextiles are studied under laminar flow conditions and at three different hydraulic gradients. Results facilitate selecting the appropriate geotextile based on permeability, filtration and clogging for use as erosion control

Geochemistry of Cu, Zn and Fe in the Tambo River, Australia II. Field investigation under low-flow conditions

2008 ◽  
Vol 59 (1) ◽  
pp. 80 ◽  
Author(s):  
Barry T. Hart ◽  
Tina Hines ◽  
Bruce A.W. Coller
Keyword(s):  
River Flow ◽  
Field Investigation ◽  
Low Flow ◽  
Flow Conditions ◽  
Study Region ◽  
Hydrous Iron Oxide ◽  
Input Region ◽  
Flow Filtration ◽  
Colloidal Fraction ◽  
Cu And Zn

The behaviour of Fe, Cu and Zn, added to the upper Tambo River (Victoria, Australia) via a metal-enriched groundwater input, was studied during a period of very low river flow. Water samples were collected over a 1.3-km section of the river located immediately downstream of the spring input. Heavy metals were separated into three fractions (dissolved, colloidal and particulate) using tangential flow filtration. Within the ‘input region’, the pH was low (5.1–5.8) and sulphate (306–359 mg L–1), total Fe (2.81 mg L–1), total Cu (19.7 mg L–1) and total Zn (24.1 mg L–1) concentrations all increased significantly. Subsequently, the total metal concentrations reduced with distance downstream of the input, and approached values similar to those recorded upstream of the input region at the end of the study region. Most of the Fe was oxidised before it entered the river as a thick hydrous iron oxide floc that travelled downstream close to the riverbed. The remaining dissolved Fe (mainly Fe(II)) that entered the river largely controlled the behaviour of Cu and Zn in the ‘active region’ (75–400 m). This Fe(II) was rapidly oxidised to Fe(III), which then removed large amounts of the dissolved Cu (65%) and Zn (55%) into the colloidal fraction. Processes such as settling of particles, dilution by groundwater inputs and sorption of dissolved Cu and Zn onto sediments removed the remainder of the Cu and Zn.

Thrombus formation on artificial surfaces: Correlative microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 840-841
Author(s):  
Quintin J. Lai ◽  
Stuart L. Cooper ◽  
Ralph M. Albrecht
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Low Voltage ◽  
Thrombus Formation ◽  
Blood Platelets ◽  
Polymer Surfaces ◽  
Flow Conditions ◽  
Transmission Electron ◽  
Adhesion Of Platelets ◽  
Microscopic Techniques

Thrombus formation and embolization are significant problems for blood-contacting biomedical devices. Two major components of thrombi are blood platelets and the plasma protein, fibrinogen. Previous studies have examined interactions of platelets with polymer surfaces, fibrinogen with platelets, and platelets in suspension with spreading platelets attached to surfaces. Correlative microscopic techniques permit light microscopic observations of labeled living platelets, under static or flow conditions, followed by the observation of identical platelets by electron microscopy. Videoenhanced, differential interference contrast (DIC) light microscopy permits high-resolution, real-time imaging of live platelets and their interactions with surfaces. Interference reflection microscopy (IRM) provides information on the focal adhesion of platelets on surfaces. High voltage, transmission electron microscopy (HVEM) allows observation of platelet cytoskeletal structure of whole mount preparations. Low-voltage, high resolution, scanning electron microscopy allows observation of fine surface detail of platelets. Colloidal gold-labeled fibrinogen, used to identify the Gp Ilb/IIIa membrane receptor for fibrinogen, can be detected in all the above microscopies.

Weekly Exercise Consistently Reinstates Positive Mood

1998 ◽  
Vol 3 (4) ◽  
pp. 271-280 ◽  
Author(s):  
Hannah Steinberg ◽  
Briony R. Nicholls ◽  
Elizabeth A. Sykes ◽  
N. LeBoutillier ◽  
Nerina Ramlakhan ◽  
...  
Keyword(s):  
Physical Exercise ◽  
Negative Mood ◽  
Real Life ◽  
Positive Mood ◽  
Field Investigation ◽  
Single Bout ◽  
Before And After ◽  
Exercise Class ◽  
Negative Feelings ◽  
Over Time

Mood improvement immediately after a single bout of exercise is well documented, but less is known about successive and longer term effects. In a “real-life” field investigation, four kinds of exercise class (Beginners, Advanced, Body Funk and Callanetics) met once a week for up to 7 weeks. Before and after each class the members assessed how they felt by completing a questionnaire listing equal numbers of “positive” and “negative” mood words. Subjects who had attended at least five times were included in the analysis, which led to groups consisting of 18, 20, 16, and 16 subjects, respectively. All four kinds of exercise significantly increased positive and decreased negative feelings, and this result was surprisingly consistent in successive weeks. However, exercise seemed to have a much greater effect on positive than on negative moods. The favorable moods induced by each class seemed to have worn off by the following week, to be reinstated by the class itself. In the Callanetics class, positive mood also improved significantly over time. The Callanetics class involved “slower,” more demanding exercises, not always done to music. The Callanetics and Advanced classes also showed significantly greater preexercise negative moods in the first three sessions. However, these differences disappeared following exercise. Possibly, these two groups had become more “tolerant” to the mood-enhancing effects of physical exercise; this may be in part have been due to “exercise addiction.”

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