Field performance of four vibrating-wire piezometer installation methods

2022 ◽  
Author(s):  
Nathan Lee Young ◽  
Jean-Michel Lemieux ◽  
Laura Mony ◽  
Alexandra Germain ◽  
Pascal Locat ◽  
...  
Keyword(s):  
Marine Sediments ◽  
Standard Method ◽  
Preferential Flow ◽  
Short Circuit ◽  
Field Performance ◽  
Pressure Data ◽  
Field Site ◽  
Vibrating Wire ◽  
Hydrogeological Setting ◽  
Bentonite Grout

Vibrating wire piezometers provide a number of advantages over the traditional hydraulic piezometer design. There are currently many methods and configurations for installing vibrating-wire piezometers, the most common being: single piezometers in sand packs (SP), multilevel piezometers in sand packs (MLSP), and fully-grouted multilevel piezometers using either bentonite (FGB) or cement-bentonite grout (FGCB). This study assesses the performance of these four different installation methods at a field site possessing complex stratigraphy, including glacial and marine sediments. To accomplish this objective, pore pressure data recorded between December 2017 and July 2019 were analyzed. Data indicate that SP, MLSP, and FGB piezometers performed most reliably, based on the fact that piezometers installed at the same depth with these methods recorded similar pressure variations that were coherent with the hydrogeological setting. Of the two fully-grouted installations using cement-bentonite grout, one installation failed completely due to a hydraulic short circuit, likely caused by preferential flow occurring along the wires of the embedded instruments. The lack of a standard method for mixing cement-bentonite grout at the time of construction likely contributed to the failure of the FGCB installations, as the grout mixture used in this study was likely too viscous to provide a suitable seal.

Field performance of a peat railway subgrade reinforced with helical screw piles

2018 ◽  
Vol 55 (12) ◽  
pp. 1888-1899 ◽  
Author(s):  
Lisa N. Wheeler ◽  
Michael T. Hendry ◽  
W. Andy Take ◽  
Neil A. Hoult
Keyword(s):  
High Speed ◽  
Field Performance ◽  
Strain Gauges ◽  
Field Site ◽  
Seasonal Fluctuations ◽  
Pile Installation ◽  
Significant Difference ◽  
Before And After ◽  
Ground Stabilization ◽  
Train Loading

Rail tracks on peat subgrades can experience significant deflections, some of which have led to derailments. A potential ground stabilization strategy is to use screw piles to reduce rail displacements; however, limited research has been undertaken to investigate the effect of these piles and their performance under cyclic train loading. A field site was instrumented and monitored before and after screw pile installation. The piles were instrumented with strain gauges, piezometers were installed in the peat, and high-speed cameras were used to measure track and subgrade displacements. The load carried by each instrumented pile was approximately 50–60 kN 3 weeks after installation, but reduced to approximately 30 kN after 6 months. Although 1 year’s worth of piezometric data were collected before installation of the piles, it is difficult to conclusively attribute the changes in pore pressures to the piles, particularly because the piezometric data collected after the pile installation were only available for the 7 months that exhibit the period of greatest seasonal fluctuations. The track support system deformations showed no significant difference pre- and post-pile installation. Therefore, based on the monitoring data at this site, it appears that the designed transfer of load from the ties to the piles through arching within the ballast layer was not realized.

scholarly journals Water flow in the active layer along an arctic slope – An investigation based on a field campaign and model simulations

2017 ◽  
Author(s):  
Sebastian F. Zastruzny ◽  
Bo Elberling ◽  
Lars Nielsen ◽  
Karsten H. Jensen
Keyword(s):  
Water Flow ◽  
Active Layer ◽  
Preferential Flow ◽  
Breakthrough Curves ◽  
Travel Times ◽  
Field Site ◽  
Arctic Ecosystems ◽  
Data Set ◽  
Discontinuous Permafrost ◽  
Geophysical Surveys

Abstract. As climate conditions change, the hydrological regime in the active layer is subject to change too. This influences the transport of solutes and the availability of nutrients, e.g. nitrogen particularly, along slopes. There is a lack of understanding the pathways and travel times of water and nutrients along slopes in discontinuous permafrost regions and how to scale changes along transects to the rest of the landscape. This study presents a comprehensive data set of a field site in Disko Island in Greenland aiming at constructing a hydrological model of the area. Data from automated weather stations, geophysical surveys, soil samples and soil sensors and tracer experiments are combined to describe the spatial variability in the field and to serve as input to a two-dimensional model (SUTRA) for simulating water and solute transport in the summer period. The model is calibrated and validated against volumetric water content and breakthrough curves of the applied tracers. Observed and simulated results suggest that the flow velocity in the active layer is directly influenced by annual precipitation patterns leading to water flow during the summer and rapid movement at the end of summer. Yearly travel times for the specific field site are simulated to be approximately 14 m/a and the highest peak velocities are most likely caused by preferential flow paths. The spatial heterogeneities linked to the frost topography seem to control the direction and velocity of flow. The observed discontinuous movement of a conservative tracer suggests that the movement of dissolved nitrogen compounds such as nitrate, being released along the slope in consequence of permafrost thawing, could possibly quickly influence nitrogen cycling at the end of the slope. This may trigger a feedback of climate changes in terms of increasing carbon sequestration due to additional plant growth in these otherwise nitrogen-limited Arctic ecosystems.

scholarly journals Combined effects of provenance and slow-release fertilizer on nursery and field performance of yellowhorn seedlings

Silva Fennica ◽  
2018 ◽  
Vol 52 (5) ◽  
Author(s):  
Yan Ao ◽  
Peter Hirst ◽  
Guolei Li ◽  
Yahui Miao ◽  
Runzhe Zhang
Keyword(s):  
Growth Response ◽  
Slow Release ◽  
Field Performance ◽  
Nutrient Content ◽  
Biodiesel Production ◽  
Growth Responses ◽  
Field Site ◽  
Trunk Diameter ◽  
Slow Release Fertilizer ◽  
One Year

Yellowhorn ( Bunge) has been widely planted for biodiesel production in China, but has frequently shown poor field performance. Container-grown yellowhorn seedlings originating from three Chinese provenances, Wengniute Qi (WQ), Alukeerqin Qi (AQ), and Shanxian (SX), were fertilized with slow-release fertilizer (SRF) at 40, 80, 120, 160 or 200 mg N seedling. Tree growth, survival and nutrient content were measured after one year’s growth in a greenhouse followed by two years in a field site. Plants from AQ and SX tended to have higher stem and root P contents in the nursery. Higher rates of SRF increased root N, and stem and root P contents. After one year in the nursery, there were a number of interactions between provenance and SRF for plant growth responses and nutrient content in the nursery, however after two years of additional growth in the field, plants from the different provenances generally responded similarly to applied SRF in the nursery, with few interactions. Final plant height was approximately 10% lower in trees from provenance SX but was not affected by application of SRF. Conversely, final trunk diameter and stem and root biomass were unaffected by provenance but increased with higher rates of applied SRF. Our results indicate that application of SRF may be a useful tool to nutrient load yellowhorn in the nursery and facilitate transplanting performance in the field. Overall, optimal nursery and field performance of yellowhorn were observed in provenance AQ at 120–200 mg N seedling SRF. We suggest that growers consider a wider range of yellowhorn provenances and SRF rates (above 200 mg N seedling) to yield even better growth response.Xanthoceras sorbifolium–1–1–1

scholarly journals PERFORMANCE EVALUATION OF PKL (PATHOR KUCHI LEAF) ELECTRICITY FOR USE IN TELEVISION AND RADIO

2020 ◽  
Vol 3 (2) ◽  
pp. 30-37
Author(s):  
K.A. Khan ◽  
Shahinul Islam ◽  
S. R. Rasel ◽  
M. A. Saime ◽  
Sazzad Hossain ◽  
...  
Keyword(s):  
Electricity Generation ◽  
Short Circuit ◽  
Storage System ◽  
Physical And Mechanical Properties ◽  
Field Performance ◽  
Titratable Acidity ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Practical Utilization ◽  
Constituent Elements

A new method of electricity generation based on Pathor Kuchi (Genus:Kalanchoe,Section:Bryophyllum) Leaf has been designed and developed at the Department of Physics, Jagannath University,Dhaka- 1100,Bangladesh.For accurate sizing of Television and Radio PKL electric modules are necessary to optimize the module size for operation. It was realized that a vast majority of rural households in Bangladesh were left unelectrified by conventional gas based electricity. The field performance studies of the technical aspects, the projected specific capital cost and the average daily generation and efficiency of the PKL module have been found for both Radio and TV from collected data. Attempts have been made to correlate certain measurable parameters with anticipated performance of the PKL system. Chemical, physical and mechanical properties of the PKL, Short Circuit Current (ISC), Open Circuit Voltage (VOC),Temperature effect of the PKL malt, pH of the PKL malt, Titratable acidity of the PKL malt, Generation of PKL electricity, Storage system of the PKL electricity, Practical utilization of PKL electricity use in Load(Television and Radio), Classification of PKL, Longevity of the PKL malt for PKL electricity generation, Preparation of PKL electric unit cell, module, panel, arrays and the constituent elements of the PKL have been studied. In experimental study, it is shown that ,the pH of the PKL malt is ≈ 4.6 (without water), pH of the PKL malt is ≈ 4.8(with 10% solution), the titratable acidity of the PKL malt is ≈ 0.88% and the constituent elements/ ions of the PKL malt is Fe++ and Cl-. Most of the results have been tabulated and graphically discussed.

Detecting a hydraulic short circuit along a monitoring well with the recovery curve of a pumping test in a confined aquifer: method and example

1998 ◽  
Vol 35 (5) ◽  
pp. 790-800 ◽  
Author(s):  
Robert P Chapuis ◽  
Djaouida Chenaf
Keyword(s):  
Preferential Flow ◽  
Short Circuit ◽  
Pumping Test ◽  
Recovery Phase ◽  
New Method ◽  
Confined Aquifer ◽  
Initial Water ◽  
Recovery Curve ◽  
Monitoring Well ◽  
Aquifer Test

It is important to verify if a monitoring well was correctly sealed into the ground to avoid preferential flow between aquifer layers (hydraulic short circuit). Previous papers have shown how to check this by variable-head permeability tests interpreted with the velocity-graph method. This paper presents a new method to make this check with the recovery curve of an aquifer test. The theory of this new method is presented. When there is a hydraulic short circuit, the drawdowns and recoveries due to a pumping test in a confined aquifer do not yield unique values of transmissivity and storativity as they should theoretically. An example is provided, that of monitoring well E1 of the Pelican River aquifer test. The pumping phase was interpreted using the methods of Theis and Cooper-Jacob. The recovery phase was interpreted by two methods: (i) the usual graph of sprime versus log (t/tprime) gave transmissivity T and either the Jacob method or the U.S. Department of the Interior Ground Water Manual gave storativity S; and (ii) the method of (sp - sprime) versus log tprime gave both T and S. As a result, four values of T and S were obtained. They differed by 9% for T and by 186% for S. According to the proposed method there was a hydraulic short circuit close to the monitoring well: it gave an initial water level that differed from the real piezometric level by 40 cm. Drawdown and recovery values were corrected for reinterpretation. The new log-log and semilog graphs yielded identical T and S values, thus validating the diagnosis of a hydraulic short circuit and illustrating the detection method.Key words: monitoring well, pumping, recovery, quality control, transmissivity, storativity.

Structural Imperfections in thin Oxide Films Formed on Some Fe- and Ni-Base Alloys

1970 ◽  
Vol 28 ◽  
pp. 510-511
Author(s):  
L. P. Lemaire ◽  
D. E. Fornwalt ◽  
F. S. Pettit ◽  
B. H. Kear
Keyword(s):  
Oxide Scale ◽  
Oxidation Process ◽  
Short Circuit ◽  
Protective Oxide ◽  
Protective Oxide Scale ◽  
Thin Oxide Films ◽  
Diffusion Paths ◽  
Oxidation Resistant ◽  
Structural Imperfections ◽  
Short Circuit Diffusion

Oxidation resistant alloys depend on the formation of a continuous layer of protective oxide scale during the oxidation process. The initial stages of oxidation of multi-component alloys can be quite complex, since numerous metal oxides can be formed. For oxidation resistance, the composition is adjusted so that selective oxidation occurs of that element whose oxide affords the most protection. Ideally, the protective oxide scale should be i) structurally perfect, so as to avoid short-circuit diffusion paths, and ii) strongly adherent to the alloy substrate, which minimizes spalling in response to thermal cycling. Small concentrations (∼ 0.1%) of certain reactive elements, such as yttrium, markedly improve the adherence of oxide scales in many alloy systems.

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