A new laboratory apparatus for measuring leakage through geomembrane holes beneath mine tailings

2017 ◽  
Vol 54 (2) ◽  
pp. 147-157 ◽  
Author(s):  
R.W.I. Brachman ◽  
P. Joshi ◽  
R.K. Rowe
Keyword(s):  
Mine Tailings ◽  
Laboratory Apparatus ◽  
Seepage Analysis ◽  
Waste Landfill ◽  
Fine Grained ◽  
Diameter Hole ◽  
Permeable Layer ◽  
New Apparatus ◽  
And Performance ◽  
Very High

The design and performance of a new laboratory apparatus for measuring leakage through geomembrane holes beneath mine tailings is presented. Finite element seepage analysis shows a negligible effect of the lateral boundary on leakage through the geomembrane hole and that the laboratory apparatus provides an excellent idealization of the deep burial conditions expected in the field. Results from four experiments are then reported to demonstrate the effectiveness of the new apparatus and gain insight on the effect of having a low permeable layer on top of the geomembrane on leakage, as may be expected for containment applications involving mine tailings. Two of the experiments simulated having fine grained tailings above the geomembrane (containing a 10 mm diameter hole) in a deep tailings storage facility with applied vertical and pore pressures of 3000 and 1500 kPa. Leakage through the hole with low permeable layer on top of the geomembrane was found to be two to four times smaller than the leakage from two other experiments with a very high permeable layer above the geomembrane (i.e., much more like a solid waste landfill configuration).

scholarly journals Leakage through a hole in a geomembrane beneath a fine-grained tailings

2021 ◽  
Author(s):  
Alan (Yung-Chin) Chou ◽  
Richard W.I. Brachman ◽  
R. Kerry Rowe
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Pressure ◽  
Small Samples ◽  
Flow Conditions ◽  
Seepage Analysis ◽  
Effective Stresses ◽  
Fine Grained ◽  
Diameter Hole ◽  
Hydraulic Conditions ◽  
Local Measurements

Leakage through a 10-mm-diameter hole in a geomembrane beneath fine-grained tailings is examined for a range of pore pressures and effective stresses. Leakage was measured in an experiment with coupled physical and hydraulic conditions to simulate the effective stresses and flow conditions near the hole. The leakage rate was at little as 0.16 L/day with 200 kPa pore pressure (10-30 kPa effective stresses) and increased only to 0.46 L/day with 800 kPa pore pressure (200 kPa effective stress). Seepage analysis of the experiment and local measurements of permeability from small samples extracted after the experiment indicate that the tailings hydraulic conductivity controlling flow was 3–6 x10-9 m/s. Only a subtle decrease in hydraulic conductivity (less than 2 times) near the hole was found. No evidence of seepage induced migration of fines within the tailings was found. Calculations with the parameters deduced from the experiment show that leakage from a tailings storage facilities containing fine-grained tailings can be limited to 1-2 L/ha/day with a geomembrane liner, even when containing up to five 10-mm-diameter holes per hectare, as opposed to an unlined facility with 3 to 4 orders of magnitude more leakage.

Noise Reduction by Using Composite Plate

2008 ◽  
Vol 47-50 ◽  
pp. 1229-1232
Author(s):  
C.W. Chau ◽  
Y.S. Choy ◽  
Kin Tak Lau ◽  
Yang Liu
Keyword(s):  
Noise Reduction ◽  
Carbon Fibers ◽  
Side Branch ◽  
Bending Stiffness ◽  
Composite Panel ◽  
Expansion Chamber ◽  
Noise Abatement ◽  
High Tension ◽  
And Performance ◽  
Very High

The plate silencer1 which consists of an expansion chamber with two side branch cavities covered by a light panel can achieve a desirable noise reduction in broadband theoretically. The concept is similar to drum silencer2. To attain optimal noise reduction, either the membrane should be of minimal weight while retaining very high tension or the panel should be kept with very high bending stiffness that is dependent on its geometry and mechanical properties. To achieve such goal, various kinds of composite system such as carbon fibers or aluminum were mounted on light core foam. A design of the composite panel which can provide a reduction in panel weight as well as enhance the bending stiffness, is introduced in this project. Predictions of the new model are to be compared with the normal foam plate in the aspects of noise reflection capability and performance of noise abatement apart from the material properties.

The moisture relations of textile fibres at high humidities

1952 ◽  
Vol 212 (1108) ◽  
pp. 112-123 ◽  
Keyword(s):  
Hysteresis Loop ◽  
Temperature Control ◽  
Experimental Methods ◽  
Reliable Information ◽  
High Humidity ◽  
New Techniques ◽  
New Apparatus ◽  
Very High ◽  
Rapid Transfer ◽  
True Equilibrium

The lack of reliable information on the absorption of moisture by hygroscopic textiles at high humidities has hitherto prevented the resolution of certain anomalies. In the present paper the conditions for the attainment of atmospheres of high humidity are discussed and new techniques are shown to be necessary. The main requirements are conditions favouring rapid transfer of moisture to the sample and adequate temperature control. A simple new apparatus is described together with the experimental methods employed. The results given show much higher sorption at very high humidities than has been previously reported, but there is no true equilibrium at saturation. The immediate saturation regain is, for practical purposes, identical with the moisture held by the fibres after centrifuging wet samples under standard conditions. It is concluded that the hysteresis loop closes at saturation. Other related phenomena are discussed.

Modification of microstructure and performance via doping Ti in W–1TiC fine-grained alloy

2021 ◽  
Vol 825 ◽  
pp. 141918
Author(s):  
Ziwei Zhang ◽  
Siqi Zhao ◽  
Yongqi Lv ◽  
Hongbo Zhang ◽  
Zhenwei Wang ◽  
...  
Keyword(s):  
Fine Grained ◽  
And Performance ◽  
Microstructure And Performance

Phosphate removal in real anaerobic supernatants: modelling and performance of a fluidized bed reactor

1998 ◽  
Vol 38 (1) ◽  
pp. 275-283 ◽  
Author(s):  
P. Battistoni ◽  
P. Pavan ◽  
F. Cecchi ◽  
J. Mata-Alvarez
Keyword(s):  
Fluidized Bed ◽  
Contact Time ◽  
Fluidized Bed Reactor ◽  
Phosphate Removal ◽  
Plant Design ◽  
Air Stripping ◽  
And Performance ◽  
Ph Range ◽  
Very High ◽  
A2o Process

Phosphate removal in anaerobic supernatant coming from a centrifugation sludge station of an A2O process is studied. A fluidized bed reactor is employed to crystallize phosphate as hydroxyapatite or struvite using only air stripping to reach the supersaturation pH. The classic composition of supernatant (alkalinity 3550 mgCaCO3/l, PO4 139 mg/l, Mg 24 mg/l) does not require any addition of chemicals for phosphate removal. Seventeen runs are performed in a bench scale FBR obtaining very high conversion and removal efficiency and phosphate loss in the effluent ≤3.5%. The use of Ca or Mg enriched supernatant has no meaningful influence on efficiency, but it determines the prevalent salt formed between MAP or HAP. Efficiency can be related to pH and sand contact time in a double saturational model. The half efficiency constants: 0.075 h for t and 7.75 pH, have an important role in the process knowledge and optimization of plant design. Exhaust sand analysis indicates the same composition at the top, bottom and mean of the sand bed (39% mol MAP and 61% mol HAP). This result together with the high half efficiency constant for contact time indicate that the phosphate growth on the bed is not competitive. Finally, the phosphate release from the plant is studied. Results show a weak release rate, equivalent to 2.8-10% d−1 phosphate as MAP, obtained at an operative pH range of 8.1-8.4.

Compensation and Convergence — Comparing and Combining Deployment Automation Approaches

2015 ◽  
Vol 24 (03) ◽  
pp. 1541001 ◽  
Author(s):  
Johannes Wettinger ◽  
Uwe Breitenbücher ◽  
Frank Leymann
Keyword(s):  
Cloud Computing ◽  
Virtual Machine ◽  
Configuration Management ◽  
Fine Grained ◽  
Design Time ◽  
Major Class ◽  
Continuous Delivery ◽  
And Performance

Leading paradigms to develop, deploy, and operate applications such as continuous delivery, configuration management, and the merge of development and operations (DevOps) are the foundation for various techniques and tools to implement automated deployment. To make such applications available for users and customers, these approaches are typically used in conjunction with Cloud computing to automatically provision and manage underlying resources such as storage and virtual servers. A major class of these automation approaches follow the idea of converging toward a desired state of a resource (e.g. a middleware component deployed on a virtual machine). This is achieved by repeatedly executing idempotent scripts to reach the desired state. Because of major drawbacks of this approach, we discuss an alternative deployment automation approach based on compensation and fine-grained snapshots using container virtualization. We perform an evaluation comparing both approaches in terms of difficulties at design time and performance at runtime. Moreover, we discuss concepts, strategies, and implementations to effectively combine different deployment automation approaches.

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