scholarly journals Evaluation of time response of GMS for soil suction measurement

2021 ◽  
Vol 337 ◽  
pp. 01014
Author(s):  
Danilo L. Vettorello ◽  
Fernando A. M. Marinho
Keyword(s):  
Water Content ◽  
Indirect Method ◽  
Civil Engineering ◽  
Time Response ◽  
Engineering Practice ◽  
Soil Suction ◽  
Residual Soil ◽  
Content Variation ◽  
Granular Matrix ◽  
Matrix Sensor

The Granular Matrix Sensor (GMS) is an indirect method for soil suction measurement. Since GMS is comparatively inexpensive, robust and usually provide continuous soil suction data, it is a natural candidate for civil engineering practice. The sensor has been used mainly for irrigation purposes, and also for some civil engineering activities. Questions about its effectiveness and reliability are still posed, making studies about this topic desirable. This study presents a laboratory comparison between Watermark and an ordinary tensiometer during an equilibrium period and for a wetting procedure performed in a compacted sandy silt soil (residual soil of gneiss). The results yielded that GMS may provide tensiometer equivalent suction values in a context of no significant water content variation. However, it takes a longer time to obtain stabilized suction values. During the wetting procedure, GMS presented a delay of about 2 h in detecting water while tensiometer detection was almost instantaneous.

Equations for the entire soil-water characteristic curve of a volume change soil

2008 ◽  
Vol 45 (4) ◽  
pp. 443-453 ◽  
Author(s):  
Hung Q. Pham ◽  
Delwyn G. Fredlund
Keyword(s):  
Soil Water ◽  
Volume Change ◽  
Curve Fitting ◽  
Characteristic Curve ◽  
Engineering Practice ◽  
Soil Suction ◽  
Residual Soil ◽  
Soil Water Characteristic Curve ◽  
Geoenvironmental Engineering ◽  
Type Studies

Numerous curve-fitting equations have been proposed for soil-water characteristic curves. While these equations have been of considerable value in geotechnical and geoenvironmental engineering, the equations are not able to adequately fit gravimetric soil-water characteristic curve data over the entire range of soil suction for a soil that changes volume when suction is changed. Two new equations for the soil-water characteristic curve are presented in this paper. One equation has curve-fitting parameters that bear a meaningful relationship to conventional physical soil properties (e.g., air-entry value and residual soil suction), but the equation is somewhat complex. The equation is particularly useful for sensitivity type studies when undertaking computer modeling. The other equation is relatively simple to use and is developed as a conventional curve-fitting equation. The two equations are used to best-fit several soil datasets. Both equations perform well and can be used in research and engineering practice to define the gravimetric water content versus soil suction relationship for a soil exhibiting volume change.

scholarly journals Methodology: non-invasive monitoring system based on standing wave ratio for detecting water content variations in plants

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Yunjeong Yang ◽  
Ji Eun Kim ◽  
Hak Jin Song ◽  
Eun Bin Lee ◽  
Yong-Keun Choi ◽  
...  
Keyword(s):  
Water Content ◽  
Monitoring System ◽  
Standing Wave ◽  
Magnetic Particles ◽  
Experimental Plant ◽  
Invasive Monitoring ◽  
Monitoring Method ◽  
Non Invasive ◽  
Content Variation ◽  
Stem Water

Abstract Background Water content variation during plant growth is one of the most important monitoring parameters in plant studies. Conventional parameters (such as dry weight) are unreliable; thus, the development of rapid, accurate methods that will allow the monitoring of water content variation in live plants is necessary. In this study, we aimed to develop a non-invasive, radiofrequency-based monitoring system to rapidly and accurately detect water content variation in live plants. The changes in standing wave ratio (SWR) caused by the presence of stem water and magnetic particles in the stem water flow were used as the basis of plant monitoring systems. Results The SWR of a coil probe was used to develop a non-invasive monitoring system to detect water content variation in live plants. When water was added to the live experimental plants with or without illumination under drought conditions, noticeable SWR changes at various frequencies were observed. When a fixed frequency (1.611 GHz) was applied to a single experimental plant (Radermachera sinica), a more comprehensive monitoring, such as water content variation within the plant and the effect of illumination on water content, was achieved. Conclusions Our study demonstrated that the SWR of a coil probe could be used as a real-time, non-invasive, non-destructive parameter for detecting water content variation and practical vital activity in live plants. Our non-invasive monitoring method based on SWR may also be applied to various plant studies.

scholarly journals Vibration Properties of a Concrete Structure with Symmetries Used in Civil Engineering

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 656
Author(s):  
Sorin Vlase ◽  
Marin Marin ◽  
Ovidiu Deaconu
Keyword(s):  
Dynamic Analysis ◽  
Concrete Structure ◽  
Current Practice ◽  
Civil Engineering ◽  
Engineering Practice ◽  
Design Time ◽  
Vibration Properties ◽  
Reduced Costs ◽  
Constructive Simplicity ◽  
Economic Considerations

The paper aims to study a concrete structure, currently used in civil engineering, which has certain symmetries. This type of problem is common in engineering practice, especially in civil engineering. There are many reasons why structures with identical elements or certain symmetries are used in industry, related to economic considerations, shortening the design time, for constructive, simplicity, cost or logistical reasons. There are many reasons why the presence of symmetries has benefits for designers, builders, and beneficiaries. In the end, the result of these benefits materializes through short execution times and reduced costs. The paper studies the eigenvalue and eigenmode properties of vibration for components of the constructions’ structure, often encountered in current practice. The identification of such properties allows the simplification and easing of the effort necessary for the dynamic analysis of such a structure.

Water content and soil suction in the capillary zone

2020 ◽  
pp. 387-391
Author(s):  
W.N. Houston ◽  
S.L. Houston ◽  
D. Al-Samahiji
Keyword(s):  
Water Content ◽  
Soil Suction ◽  
Capillary Zone

scholarly journals Optimum time of sowing for rainfed winter chickpea with one-pass mechanised row-sowing: an example for small-holder farms in north-west Bangladesh

2014 ◽  
Vol 65 (7) ◽  
pp. 602 ◽  
Author(s):  
W. H. Vance ◽  
R. W. Bell ◽  
C. Johansen ◽  
M. E. Haque ◽  
A. M. Musa ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Crop Growth ◽  
Residual Soil ◽  
Reproductive Growth ◽  
Sowing Time ◽  
Minimum Tillage ◽  
North West ◽  
Sowing Dates

The time of sowing chickpea (Cicer arietinum L.) in the High Barind Tract of north-west Bangladesh is critical to crop success. To ensure adequate emergence and subsequent crop growth, chickpea relies on residual soil moisture stored in the profile after rice (Oryza sativa L.) cultivated in the preceding rainy season. With the development of mechanised, one-pass minimum tillage sowing, the time between rice harvest and chickpea sowing is decreased, and temperature constraints that limit biomass and/or pod formation and filling may be avoided. Minimum tillage may also limit evaporation from the soil surface compared with traditional, full cultivation procedures. The objective of this study was to identify the optimum sowing time to achieve adequate crop establishment and limit exposure of the chickpea crop to terminal drought and heat stress later in the growing season. Over three experimental seasons, chickpea sowing dates were spread from 22 November to 22 December. Soil water content, crop growth and temperature were monitored to determine the optimum sowing time. Over all seasons and sowing dates, the volumetric soil water content in the seedbed under minimum tillage remained within 17–34%, a range non-limiting for chickpea establishment in glasshouse and field experiments. Late planting (after 10 December) exposed seedlings to low temperatures (<15°C), which limited biomass formation and extended the vegetative growth phase into periods with high maximum temperatures (>35°C), resulting in unfilled pods and depressed grain yield. The preferred sowing time was determined to be 30 November to 10 December to reduce the risk of high temperatures and low soil water content during chickpea reproductive growth causing terminal heat and drought stress, respectively. Mechanised sowing in one operation allows farmers to optimise their time of sowing to match seed requirements for soil water at emergence and may assist farmers to avoid temperature stresses (both low and high) that constrain chickpea vegetative and reproductive growth.

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