scholarly journals “Monitoring soil salinity using time-lapse electromagnetic conductivity imaging” - authors’ responses to suggestions and comments made in Public Discussion

2020 ◽  
Author(s):  
Mohammad Farzamian
Keyword(s):  
Soil Salinity ◽  
Time Lapse ◽  
Public Discussion ◽  
Conductivity Imaging ◽  
Made In

scholarly journals Assessing soil salinity dynamics using time-lapse electromagnetic conductivity imaging

SOIL ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 499-511
Author(s):  
Maria Catarina Paz ◽  
Mohammad Farzamian ◽  
Ana Marta Paz ◽  
Nádia Luísa Castanheira ◽  
Maria Conceição Gonçalves ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Cross Sections ◽  
Soil Salinity ◽  
Sea Water ◽  
Management Strategies ◽  
Time Lapse ◽  
Soil Salinization ◽  
Agricultural System ◽  
Prediction Ability ◽  
Conductivity Imaging

Abstract. Lezíria Grande de Vila Franca de Xira, located in Portugal, is an important agricultural system where soil faces the risk of salinization due to climate change, as the level and salinity of groundwater are likely to increase as a result of the rise of the sea water level and consequently of the estuary. These changes can also affect the salinity of the irrigation water which is collected upstream of the estuary. Soil salinity can be assessed over large areas by the following rationale: (1) use of electromagnetic induction (EMI) to measure the soil apparent electrical conductivity (ECa, mS m−1); (2) inversion of ECa to obtain electromagnetic conductivity imaging (EMCI) which provides the spatial distribution of the soil electrical conductivity (σ, mS m−1); (3) calibration process consisting of a regression between σ and the electrical conductivity of the saturated soil paste extract (ECe, dS m−1), used as a proxy for soil salinity; and (4) conversion of EMCI into salinity cross sections using the obtained calibration equation. In this study, EMI surveys and soil sampling were carried out between May 2017 and October 2018 at four locations with different salinity levels across the study area of Lezíria de Vila Franca. A previously developed regional calibration was used for predicting ECe from EMCI. Using time-lapse EMCI data, this study aims (1) to evaluate the ability of the regional calibration to predict soil salinity and (2) to perform a preliminary qualitative analysis of soil salinity dynamics in the study area. The validation analysis showed that ECe was predicted with a root mean square error (RMSE) of 3.14 dS m−1 in a range of 52.35 dS m−1, slightly overestimated (−1.23 dS m−1), with a strong Lin's concordance correlation coefficient (CCC) of 0.94 and high linearity between measured and predicted data (R2=0.88). It was also observed that the prediction ability of the regional calibration is more influenced by spatial variability of data than temporal variability of data. Soil salinity cross sections were generated for each date and location of data collection, revealing qualitative salinity fluctuations related to the input of salts and water either through irrigation, precipitation, or level and salinity of groundwater. Time-lapse EMCI is developing into a valid methodology for evaluating the risk of soil salinization, so it can further support the evaluation and adoption of proper agricultural management strategies, especially in irrigated areas, where continuous monitoring of soil salinity dynamics is required.

scholarly journals A NuSTAR confirmation of the 36 ks hard X-ray pulse-phase modulation in the magnetar 1E 1547.0 − 5408

2021 ◽  
Vol 502 (2) ◽  
pp. 2266-2284
Author(s):  
Kazuo Makishima ◽  
Teruaki Enoto ◽  
Hiroki Yoneda ◽  
Hirokazu Odaka
Keyword(s):  
Time Lapse ◽  
Phase Behaviour ◽  
Modulation Amplitude ◽  
Axial Deformation ◽  
Physical Processes ◽  
Arrival Times ◽  
Pulse Phase ◽  
Phase Variations ◽  
Complex Phenomena ◽  
Made In

ABSTRACT This paper describes an analysis of the NuSTAR data of the fastest-rotating magnetar 1E 1547 − 5408, acquired in 2016 April for a time lapse of 151 ks. The source was detected with a 1–60 keV flux of 1.7 × 10−11 erg s−1 cm−2, and its pulsation at a period of 2.086710(5) s. In 8–25 keV, the pulses were phase-modulated with a period of T = 36.0 ± 2.3 ks, and an amplitude of ∼0.2 s. This reconfirms the Suzaku discovery of the same effect at $T=36.0 ^{+4.5}_{-2.5}$ ks, made in the 2009 outburst. These results strengthen the view derived from the Suzaku data, that this magnetar performs free precession as a result of its axial deformation by ∼0.6 × 10−4, possibly caused by internal toroidal magneti fields (MFs) reaching ∼1016 G. Like in the Suzaku case, the modulation was not detected in energies below ∼8 keV. Above 10 keV, the pulse-phase behaviour, including the 36 ks modulation parameters, exhibited complex energy dependencies: at ∼22 keV, the modulation amplitude increased to ∼0.5 s, and the modulation phase changed by ∼65° over 10–27 keV, followed by a phase reversal. Although the pulse significance and pulsed fraction were originally very low in >10 keV, they both increased noticeably, when the arrival times of individual photons were corrected for these systematic pulse-phase variations. Possible origins of these complex phenomena are discussed, in terms of several physical processes that are specific to ultrastrong MFs.

Prediction of soil salinity and sodicity using electromagnetic conductivity imaging

Geoderma ◽  
2020 ◽  
Vol 361 ◽  
pp. 114086 ◽  
Author(s):  
Ana Marta Paz ◽  
Nádia Castanheira ◽  
Mohammad Farzamian ◽  
Maria Catarina Paz ◽  
Maria Conceição Gonçalves ◽  
...  
Keyword(s):  
Soil Salinity ◽  
Conductivity Imaging

Design of tunnel lining in rock for long term time effects

1981 ◽  
Vol 18 (1) ◽  
pp. 24-39 ◽  
Author(s):  
K. Y. Lo ◽  
Clement M. K. Yuen
Keyword(s):  
Time Lapse ◽  
Time Dependent ◽  
Initial Stresses ◽  
Time Interaction ◽  
Underground Openings ◽  
Rock Structure ◽  
Rock Movement ◽  
Made In

Excavation of underground openings in rock relieves the in situ state of stresses, providing an initiating mechanism for time-dependent deformation in shaly rocks to occur. The construction of a permanent lining restrains the rock movement, resulting in an increase with time of pressure acting on the lining.Closed form solutions for this problem of rock structure – time interaction of circular tunnels have been developed, taking into account (a) the state of initial stresses, (b) the time-dependent properties of the lining as well as the rock, and (c) the time lapsed between excavation and lining. Expressions for lining pressures, stresses, thrusts, and moments are given for both "no slip" and "full slip" interface conditions.The effects of material parameters, lining flexibilities, and time lapse on quantities of engineering interest are studied and their implications on design illustrated.The results of analysis are compared with the field observations made in three tunnels. It is shown that the theoretical results are consistent with the observed extent and location of cracking in these tunnels.It is suggested that the methods proposed may be used for design considerations of permanent linings of tunnels in rock exhibiting significant time-dependent deformation.

scholarly journals The reorganization of microfilaments, centrosomes, and microtubules during in vitro small wound reendothelialization.

1988 ◽  
Vol 107 (5) ◽  
pp. 1777-1783 ◽  
Author(s):  
M K Wong ◽  
A I Gotlieb
Keyword(s):  
Cell Spreading ◽  
Time Lapse ◽  
Repair Process ◽  
Specific Sequence ◽  
Actin Microfilament ◽  
Wound Model ◽  
Microfilament Bundles ◽  
Endothelial Integrity ◽  
Made In

The repair of small endothelial wounds is an important process by which endothelial cells maintain endothelial integrity. An in vitro wound model system was used in which precise wounds were made in a confluent endothelial monolayer. The repair process was observed by time-lapse cinemicrophotography. Using fluorescence and immunofluorescence microscopy, the cellular morphological events were correlated with the localization and distribution of actin microfilament bundles and vinculin plaques, and centrosomes and their associated microtubules. Single to four-cell wounds underwent closure by cell spreading while wounds seven to nine cells in size closed by initially spreading which was then followed at approximately 1 h after wounding by cell migration. These two processes showed different cytoskeletal patterns. Cell spreading occurred independent of centrosome location. However, centrosome redistribution to the front of the cell occurred as the cells began to elongate and migrate. While the peripheral actin microfilament bundles (i.e., the dense peripheral band) remained intact during cell spreading, they broke down during migration and were associated with a reduction in peripheral vinculin plaque staining. Thus, the major events characterizing the closure of endothelial wounds were precise in nature, followed a specific sequence, and were associated with specific cytoskeletal patterns which most likely were important in maintaining directionality of migration and reducing the adhesion of the cells to their neighbors within the monolayer.

scholarly journals LEAKAGE OF UV-ABSORBING SOLUTES FROM SALT-AFFECTED ROOT TIPS OF PISTACHIO ROOTSTOCKS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1136e-1136
Author(s):  
G.A. Picchioni ◽  
S. Miyamoto ◽  
J.B. Storey
Keyword(s):  
Root Growth ◽  
Soil Salinity ◽  
Cellular Damage ◽  
Root Tips ◽  
Pistacia Atlantica ◽  
Solute Leakage ◽  
Soil Solutions ◽  
Saline Solutions ◽  
Made In

Excised root tips from 3-year-old pistachio rootstock (Pistacia atlantica Desf., P. terebinthus L., and P. integerrima Stewart × atlantica) were exposed to laboratory saline solutions for 24 hr. Treatments simulated the compositions of soil solutions in a previous 2-year study made in outdoor lysimeters. Leakage of UV-absorbing solutes, an indication of cellular damage, occurred with 175 mM Na/12.5 mM Ca, which was comparable to soil salinity which increased leaf Na concentrations and decreased root growth of these species Up to. five times higher leakage occurred from roots of a P. terebinthus genotype having least Na exclusion potential during the lysimeter study. Use of isotonic levels of CaCl2, mannitol, and simulated Na/Ca solutions resulted in similar damage. However, isotonic Na (-Ca) caused highest leakage overall. Correlation between long-term observations in the lysimeters and leakage occurrence-in the laboratory indicates that solute leakage tests may aid in characterizing responses of Pistacia spp. roots cocks to saline conditions.

scholarly journals Application of kriging techniques for assessing the salinity of irrigated soils: the case of El Ghrous perimeter, Biskra, Algeria

2019 ◽  
Vol 9 ◽  
Author(s):  
Mohamed Amine Abdennour ◽  
Abdelkader Douaoui ◽  
Abdelhamid Bradai ◽  
Amel Bennacer ◽  
Manuel Pulido Fernández
Keyword(s):  
Soil Salinity ◽  
Ordinary Kriging ◽  
Indicator Kriging ◽  
Spatial Trend ◽  
Risk Areas ◽  
Geostatistical Techniques ◽  
Anthropogenic Processes ◽  
Irrigated Perimeter ◽  
Made In ◽  
Irrigated Soils

In semi-arid and arid areas, soil salinity has adverse effects both on the environment and agricultural production. The main causes of this salinization come from natural or anthropogenic processes, which is certainly an environmental problem that affects more than 20% of the world's land. This study was made in order to map the spatial distribution of soil salinity of the irrigated perimeter of El Ghrous in southeastern Algeria. These maps were performed based on data collected from 190 soil samples from 0 to 15 cm deep. We used ordinary kriging (OK) to analyze the spatial variability of soil salinity, while indicator kriging (IK) was used to analyze salinity versus threshold values. The salinity map predicted by the electrical conductivity (EC) values using the ordinary kriging (OK) method showed the different classes of salinity according to Durand's classification with moderately saline 3rd order dominance, while the unsalted soil (EC &lt; 0.6 dS m<sup>-1</sup>) represents a very low percentage (1.5%). The indicator kriging (IK) was carried out by four thresholds which correspond to the salinity class limits: EC &gt; 0.6, EC &gt; 1, EC &gt; 2, EC &gt; 3, and EC &gt; 4 dS m<sup>-1</sup>, for developing probability maps to determine risk areas. This study has shown the spatial trend of soil salinity by geolocation of different classes, and to carry out risk maps using geostatistical techniques.

scholarly journals Assessing the dynamics of soil salinity with time-lapse inversion of electromagnetic data guided by hydrological modelling

2021 ◽  
Vol 25 (3) ◽  
pp. 1509-1527
Author(s):  
Mohammad Farzamian ◽  
Dario Autovino ◽  
Angelo Basile ◽  
Roberto De Mascellis ◽  
Giovanna Dragonetti ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Electromagnetic Induction ◽  
Irrigation System ◽  
Time Lapse ◽  
Hydrological Modelling ◽  
Irrigated Agriculture ◽  
Field Assessment ◽  
Apparent Electrical Conductivity ◽  
Spatio Temporal

Abstract. Irrigated agriculture is threatened by soil salinity in numerous arid and semi-arid areas of the world, chiefly caused by the use of highly salinity irrigation water, compounded by excessive evapotranspiration. Given this threat, efficient field assessment methods are needed to monitor the dynamics of soil salinity in salt-affected irrigated lands and evaluate the performance of management strategies. In this study, we report on the results of an irrigation experiment with the main objective of evaluating time-lapse inversion of electromagnetic induction (EMI) data and hydrological modelling in field assessment of soil salinity dynamics. Four experimental plots were established and irrigated 12 times during a 2-month period, with water at four different salinity levels (1, 4, 8 and 12 dS m−1) using a drip irrigation system. Time-lapse apparent electrical conductivity (σa) data were collected four times during the experiment period using the CMD Mini-Explorer. Prior to inversion of time-lapse σa data, a numerical experiment was performed by 2D simulations of the water and solute infiltration and redistribution process in synthetic transects, generated by using the statistical distribution of the hydraulic properties in the study area. These simulations gave known spatio-temporal distribution of water contents and solute concentrations and thus of bulk electrical conductivity (σb), which in turn were used to obtain known structures of apparent electrical conductivity, σa. These synthetic distributions were used for a preliminary understanding of how the physical context may influence the EMI-based σa readings carried out in the monitored transects as well as being used to optimize the smoothing parameter to be used in the inversion of σa readings. With this prior information at hand, we inverted the time-lapse field σa data and interpreted the results in terms of concentration distributions over time. The proposed approach, using preliminary hydrological simulations to understand the potential role of the variability of the physical system to be monitored by EMI, may actually allow for a better choice of the inversion parameters and interpretation of EMI readings, thus increasing the potentiality of using the electromagnetic induction technique for rapid and non-invasive investigation of spatio-temporal variability in soil salinity over large areas.

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