Grouted-in installation of piezometers in boreholes

1995 ◽  
Vol 32 (2) ◽  
pp. 355-363 ◽  
Author(s):  
Gordon T. McKenna
Keyword(s):  
Oil Sands ◽  
Theoretical Basis ◽  
Time Lag ◽  
Fast Response ◽  
Soil Conditions ◽  
Pressure Equalization ◽  
Pore Water Pressures ◽  
Small Change ◽  
Installation Cost ◽  
Bentonite Grout

Because a modern diaphragm-type piezometer tip only requires a small change in fluid volume for pressure equalization, the conventional, large sand intake zone around the piezometer tip can be omitted, and the tip can be grouted in a borehole with cement–bentonite grout. This grouted-in installation method allows simpler and easier installation, accurate readings, fast response to changing formation pore-water pressures, installation in boreholes shared with other geotechnical instruments, and can save 10–75% on the installation cost of a piezometer. The grouted-in installation method can be used for most soil conditions provided that the grout is less permeable than the formation. A theoretical basis for the grouted-in installation method is presented with supporting laboratory and field data from the Syncrude Canada Ltd. oil sands mine. Key words : piezometer, grout, instrumentation, hydraulic conductivity, hydrodynamic time lag, oil sands.

Nighttime doesn’t stop N2O and CH4 exchange from riparian forest tree stems with the atmosphere

2020 ◽  
Author(s):  
Thomas Schindler ◽  
Katerina Machacova ◽  
Ülo Mander ◽  
Kaido Soosaar
Keyword(s):  
Forest Ecosystems ◽  
Riparian Forest ◽  
Fast Response ◽  
Forest Tree ◽  
Soil Conditions ◽  
Ministry Of Education ◽  
Stem Height ◽  
Night Time ◽  
Sustainability Program ◽  
A Minor

<p>Riparian forest ecosystems have been considered to be a natural source of nitrous oxide (N<sub>2</sub>O) and a natural sink of methane (CH<sub>4</sub>), both of which are important greenhouse gases (GHG) originating from microbiological processes. Wetland trees may also contribute to the GHG exchange by the release of both gases to the atmosphere or uptake therefrom. Recent studies have investigated the role of tree stems, underlining their importance in understanding forest GHG dynamics, focussing on various tree species, soil conditions or seasonal dynamics. However, knowledge about the short-termed day and night-time distributed GHG exchange of tree stems with the atmosphere is still scarce. We studied stem fluxes in a riparian forest ecosystem aiming to investigate the diurnal pattern and predict the potential influence of solar radiation.</p><p>The diurnal flux measurements were performed at 40-year-old grey alder (Alnus incana) forest stand in Estonia with 12-hour interval during July-September 2017 and May-September 2018 (n=16). The exchange of N<sub>2</sub>O and CH<sub>4</sub> was measured from 12 trees at profile height up to 5 m (0.1, 0.8, 1.7, 2.5, 5.0 m) using non-steady state stem chamber systems and gas chromatography. Simultaneously, soil fluxes were automatically quantified using a dynamic chamber system (Picarro 2508); piezometers, automatic groundwater level wells, soil temperature and moisture sensors were installed to determine coherent soil conditions.</p><p>Our preliminary results showed N<sub>2</sub>O and CH<sub>4</sub> emissions from alder tree stems during daytime (4.91 ± 0.15 µg m<sup>-2</sup> h<sup>-1</sup> and 66.38 ± 16.02 µg m<sup>-2</sup> h<sup>-1</sup>, mean ± s.e.) and lower during nighttime (3.65 ± 0.22 µg m<sup>-2</sup> h<sup>-1</sup> and 51.49 ± 13.83 µg m<sup>-2</sup> h<sup>-1</sup>, mean ± s.e.) at 0.1 m stem height, revealing a likely link to solar-driven physiological tree activity. Further, with increasing stem height, the relation of night to daytime fluxes diminished. However, the day-wise variation, including a minor GHG uptake indicates a fast response to changing micro-spatial environmental conditions like water regime in the soil and temperature.</p><p>Our study demonstrates the GHG exchange between tree stems and atmosphere occurs both in day- and night-time, showing slightly higher values in day-time, probably due to the trees’ physiological activities. Furthermore, our findings provide the potential to predict reaction kinetics in future modelling of flux pathways in forest ecosystems.</p><p>Acknowledgement</p><p>This research was supported by the Ministry of Education and Science of Estonia (SF0180127s08 grant), the Estonian Research Council (IUT2-16, PRG-352, and MOBERC20), the Czech Science Foundation (17-18112Y), the Czech National Sustainability Program I (LO1415), and the EcolChange Centre of Excellence, Estonia.</p>

scholarly journals Measuring the biosphere-atmosphere exchange of total reactive nitrogen by eddy covariance

2012 ◽  
Vol 9 (11) ◽  
pp. 4247-4261 ◽  
Author(s):  
C. Ammann ◽  
V. Wolff ◽  
O. Marx ◽  
C. Brümmer ◽  
A. Neftel
Keyword(s):  
Eddy Covariance ◽  
Measurement Techniques ◽  
Time Lag ◽  
Fast Response ◽  
Average Concentration ◽  
Reactive Nitrogen ◽  
Gradient Technique ◽  
Measurement Height ◽  
Flux Measurements ◽  
Trace Compounds

Abstract. The (net) exchange of reactive nitrogen (Nr) with the atmosphere is an important driver for ecosystem productivity and greenhouse gas exchange. The exchange of airborne Nr includes various trace compounds that usually require different specific measurement techniques, and up to now fast response instruments suitable for eddy covariance measurements are only available for few of these compounds. Here we present eddy covariance flux measurements with a recently introduced converter (TRANC) for the sum of all Nr compounds (∑Nr). Measurements were performed over a managed grassland field with phases of net emission and net deposition of ∑Nr and alternating dominance of oxidized (NOX) and reduced species (NH3). Spectral analysis of the eddy covariance data exhibited the existence of covariance function peaks at a reasonable time lag related to the sampling tube residence time under stationary conditions. Using ogive analysis, the high-frequency damping was quantified to 19%–26% for a low measurement height of 1.2 m and to about 10% for 4.8 m measurement height. ∑Nr concentrations and fluxes were compared to parallel NO and NO2 measurements by dynamic chambers and NH3 measurements by the aerodynamic gradient technique. The average concentration results indicate that the main compounds NO2 and NH3 were converted by the TRANC system with an efficiency of near 100%. With an optimised sample inlet also the fluxes of these compounds were recovered reasonably well including net deposition and net emission phases. The study shows that the TRANC system is suitable for fast response measurements of oxidized and reduced nitrogen compounds and can be used for continuous eddy covariance flux measurements of total reactive nitrogen.

A Fuzzy Predictive Controlling Method of Fermentation Tank Temperature

2014 ◽  
Vol 1037 ◽  
pp. 248-252
Author(s):  
Tao He ◽  
Xiang Hu ◽  
Jiu Yin Chen ◽  
Xian Wang
Keyword(s):  
Design Method ◽  
Time Lag ◽  
Fast Response ◽  
Static Characteristic ◽  
Data Simulation ◽  
Industrial Control ◽  
Industrial Control Systems ◽  
Precise Control ◽  
Fermentation Tank

Liquor fermentation is a complex biochemical process, to control the temperature of fermentation tank fastly and accurately in the process can improve the efficiency and quality of fermentation .Because of the nonlinear and time lag of the process, meanwhile the conventional PID control and is difficult to solve practical problems in precise control,So this paper puts forward a fuzzy predictive controlling method, by combining the advantages of fuzzy control and predictive control for big lag, nonlinear fermentation systems.After using MATLAB to make comparative data simulation, the result shows that the proposed design method can better dynamic and static characteristics of both system, with static characteristic small overshoot, fast response, high steady precision, etc, can be useful in industrial control systems.

scholarly journals Measuring the biosphere-atmosphere exchange of total reactive nitrogen by eddy covariance

2012 ◽  
Vol 9 (6) ◽  
pp. 6857-6898 ◽  
Author(s):  
C. Ammann ◽  
V. Wolff ◽  
O. Marx ◽  
C. Brümmer ◽  
A. Neftel
Keyword(s):  
Eddy Covariance ◽  
Measurement Techniques ◽  
Time Lag ◽  
Fast Response ◽  
Average Concentration ◽  
Reactive Nitrogen ◽  
Gradient Technique ◽  
Measurement Height ◽  
Flux Measurements ◽  
Trace Compounds

Abstract. The (net) exchange of reactive nitrogen (Nr) with the atmosphere is an important driver for ecosystem productivity and greenhouse gas exchange. The exchange of airborne Nr includes various trace compounds that usually require different specific measurement techniques, and up to now fast response instruments suitable for eddy covariance measurements are only available for few of these compounds. Here we present eddy covariance flux measurements with a recently introduced converter (TRANC) for the sum of all Nr compounds (∑Nr). Measurements were performed over a managed grassland field with phases of net emission and net deposition of ∑Nr and alternating dominance of oxidized (NOx) and reduced species (NH3). Spectral analysis of the eddy covariance data exhibited the existence of covariance function peaks at a reasonable time lag related to the sampling tube residence time under stationary conditions. Using ogive analysis, the high-frequency damping was quantified to 19–26% for a low measurement height of 1.2 m and to about 10% for 4.8 m measurement height. ∑Nr concentrations and fluxes were compared to parallel NO and NO2 measurements by dynamic chambers and NH3 measurements by the aerodynamic gradient technique. The average concentration results indicate that close-to-full conversion of the main compounds NO2 and NH3 was generally obtained by the TRANC system. With an optimised sample inlet also the fluxes of these compounds were recovered fairly including net deposition and net emission phases. The study shows that the TRANC system is suitable for fast response measurements of oxidized and reduced nitrogen compounds and can be used for continuous eddy covariance flux measurements of total reactive nitrogen.

scholarly journals Microfluidic Devices: Applications and Role of Surface Wettability in Its Fabrication

2020 ◽  
Author(s):  
Shivanjali Saxena ◽  
Rakesh Joshi
Keyword(s):  
Microfluidic Devices ◽  
Fast Response ◽  
Surface Wettability ◽  
Cost Ratio ◽  
Fluid Properties ◽  
Single Field ◽  
Small Change ◽  
Wettability Measurement

Microfluidic devices are based upon the behavior of fluids at the microenvironment level. They offer innumerable applications in the field of science and technology. Their scope is not limited to single field and now have applications in various fields such as biomedical, energy, chemicals and environment as well. Their major advantages are low experiment to cost ratio, and fast response time. Surface wettability is one of the factors contributing to the working of microfluidic devices. Surface wettability measurement is a very critical technique to measure the flow of micro fluids in microfluidic applications. In microfluidic devices the detection of small volume change with change in fluid properties is very minor because of the micrometer range. In order to detect this small change in micrometer range, an in situ wetting measurement is required. In this chapter, we have discussed about types of taxis, microfluidic devices: an application of taxis, microfluidic applications and role of surface wettability in microfluidic devices.

scholarly journals Quartz Tuning Fork Sensor-Based Dosimetry for Sensitive Detection of Gamma Radiation

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7035
Author(s):  
Nadyah Alanazi ◽  
Abdullah N. Alodhayb ◽  
Atheer Almutairi ◽  
Hanan Alshehri ◽  
Sarah AlYemni ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Resonance Frequency ◽  
Tuning Fork ◽  
Low Cost ◽  
Radiation Detector ◽  
Quartz Tuning Fork ◽  
Fast Response ◽  
Gold Coating ◽  
Before And After ◽  
Small Change

This study generally relates to nuclear sensors and specifically to detecting nuclear and electromagnetic radiation using an ultrasensitive quartz tuning fork (QTF) sensor. We aim to detect low doses of gamma radiation with fast response time using QTF. Three different types of QTFs (uncoated and gold coated) were used in this study in order to investigate their sensitivity to gamma radiations. Our results show that a thick gold coating on QTF can enhance the quality factor and increase the resonance frequency from 32.7 to 32.9 kHz as compared to uncoated QTF. The results also show that increasing the surface area of the gold coating on the QTF can significantly enhance the sensitivity of the QTF to radiation. We investigated the properties of gold-coated and uncoated QTFs before and after irradiation by scanning electron microscopy. We further investigated the optical properties of SiO2 wafers (quartz) by spectroscopic ellipsometry (SE). The SE studies revealed that even a small change in the microstructure of the material caused by gamma radiation would have an impact on mechanical properties of QTF, resulting in a shift in resonance frequency. Overall, the results of the experiments demonstrated the feasibility of using QTF sensors as an easy to use, low-cost, and sensitive radiation detector.

scholarly journals Determination of oceanic ozone deposition by ship-borne eddy covariance flux measurements

2010 ◽  
Vol 3 (2) ◽  
pp. 441-455 ◽  
Author(s):  
L. Bariteau ◽  
D. Helmig ◽  
C. W. Fairall ◽  
J. E. Hare ◽  
J. Hueber ◽  
...  
Keyword(s):  
Time Lag ◽  
Fast Response ◽  
Ozone Deposition ◽  
Ozone Flux ◽  
The North ◽  
Flux System ◽  
Deposition Velocities ◽  
Flux Measurements ◽  
Chemical Analyzer

Abstract. A fast response ozone analyzer based on the ozone-nitric oxide chemiluminescence method was integrated into the NOAA-ESRL flux system to achieve the first ship-borne, direct ozone flux measurements over the open ocean. Air was collected from an inlet at 18 m height over the ocean surface mounted to the bow-jackstaff and via a 30 m-long sampling line to the ozone instrument on the ship deck. A "puff" system was used for accurate and regular determination of the sample transport time (lag) between the inlet and the chemical analyzer. A Nafion-membrane dryer facilitated removal of fast water vapor fluctuations, which eliminated the need for quenching and density correction of the ozone signal. The sampling-analyzer system was found to have a ~0.25–0.40 s response time at a sensitivity of ~2800 counts s−1 per ppbv of ozone. Quality control and data filtering procedures for eliminating data that did not meet measurement requirements were critically evaluated. The new ozone flux system was deployed aboard the NOAA Ship Ronald H. Brown, and evaluated using results obtained during several research cruises off the coasts of the North and South America continents, yielding ozone deposition velocities (mean ± standard error) ranging from 0.009±0.001 cm s−1 to 0.24±0.020 cm s−1.

On a Piezoelectric Flapper Type Servovalve Operated by a Pulse-Width-Modulated-Signal

1974 ◽  
Vol 96 (1) ◽  
pp. 88-94 ◽  
Author(s):  
Y. Ikebe ◽  
T. Nakada
Keyword(s):  
Theoretical Basis ◽  
Pulse Width ◽  
Pulse Width Modulation ◽  
Fast Response ◽  
Experimental Frequency ◽  
Nonlinear Characteristics ◽  
Pulse Width Modulated ◽  
Frequency Responses ◽  
Pulse Width Modulator ◽  
Modulation Control

As a first step to developing a servovalve with minimum moving parts, a new servovalve is devised in which a piezoelectric flapper (a quartz strip) is used instead of a conventional flapper actuated through a torque motor. A servovalve of this type is desirable from the viewpoint of fast response, however it has not been in common use because of the strong hysteresis of piezoelectric material. In order to linearize the nonlinear characteristics of the flapper, a pulse width modulated wave is used as the input signal to the flapper. The frequency characteristics of the pulse width modulator is theoretically analyzed in detail to establish the theoretical basis of the pulse width modulation control system. As well-known, this basis has been ambiguous so far. The experimental frequency responses show that the bandwidth of the servovalve using this new technique is comparable to that of conventional valves having the same power output in spite of its simple construction in comparison with conventional ones.

scholarly journals VELOCITY AND STRESS MEASUREMENTS IN A TIDAL INLET

1978 ◽  
Vol 1 (16) ◽  
pp. 77
Author(s):  
David A. Huntley ◽  
Dag Nummedal
Keyword(s):  
Single Point ◽  
Time Lag ◽  
Low Frequency ◽  
Fast Response ◽  
Significant Feature ◽  
Wave Direction ◽  
Mean Flow ◽  
Wave Velocities ◽  
Wave Effects ◽  
The Mean

Fast-response electromagnetic flowmeters were used in a marginal flood channel of an ebb tidal delta to assess the importance of wave contributions to the flood dominance of these channels. Measurements were made at a single point in the channel in both ebb and flood currents. The oscillatory motion of waves was a very significant feature of the velocity records, and its magnitude was comparable with the mean flow at all stages of the tide. This observation shows that flowmeters capable of responding accurately to wave velocities are needed to obtain accurate values of mean flow. Some earlier measurements made with slow response flowmeters are probably unreliable. Wave contributions to the mean flow were assessed by looking at the correlation between the low frequency (>17.5s) oscillations of the along-channel current and the low frequency envelope of the wave velocities. Surprisingly little correlation was found for any time lag, suggesting that wave effects were not important in the mean tidal currents in the channel studied. However, close to low tide on the ebb, conditions existed which appear to have been favourable for the "wave pump" mechanism suggested by Bruun andViggisson (1973). Significant correlation between the wave envelope and low frequency fluctuations was observed at this time. It is therefore suggested that wave effects can be important to the mean flow in marginal channels with rapidly converging and shoaling mouths which are oriented towards the dominant incident wave direction.

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