Estimating solution extract salinity from soil paste electrical conductivity - an evaluation of procedures

Soil Research ◽  
1990 ◽  
Vol 28 (4) ◽  
pp. 517 ◽  
Author(s):  
PG Slavich ◽  
GH Petterson
Keyword(s):  
Electrical Conductivity ◽  
Current Flow ◽  
Saturated Soil ◽  
Charge Component ◽  
Empirical Relationships ◽  
Standard Soil ◽  
Labour Requirement ◽  
Plant Salt Tolerance ◽  
Flow Pathway ◽  
Small Improvement

The electrical conductivity (EC) of a saturated soil paste extract (ECe) is the standard soil salinity measurement used to assess plant salt tolerance. Recently, a less time consuming method for the laboratory measurement of ECe was proposed that estimates ECe from EC measurements made directly in the saturated soil paste (ECp). The method uses a soil EC model and two empirical relationships developed with American soils. The empirical relationships are used to estimate the surface charge component of EC (ECs) and the water content of the continuous liquid current flow pathway (Bwc) from the saturation percentage (SP). This paper demonstrates that the same method may be successfully applied to Riverine Plain soils of S.E. Australia. The empirical relationships determined with Riverine Plain soils differed slightly from those published for American soils and gave a small improvement in accuracy. The method reduces the labour requirement of ECe measurements by approximately half.

Structural and Electrical Properties of Titania Thin Films

2014 ◽  
Vol 925 ◽  
pp. 300-303 ◽  
Author(s):  
Sharipah Nadzirah ◽  
Uda Hashim ◽  
N. Malihah
Keyword(s):  
Thin Films ◽  
Electrical Conductivity ◽  
Titanium Dioxide ◽  
Current Flow ◽  
Sol Gel ◽  
Particle Sizes ◽  
Structural And Electrical Properties ◽  
Crystallite Sizes ◽  
Average Current ◽  
Flow Through

This research studies the properties of titanium dioxide (TiO2) nanoparticles synthesized by two different stabilizers via sol-gel method. Acetic and hydrochloric acids have been used as stabilizers to form two different TiO2 thin films. 100 μm gap of Al IDEs have been fabricated on each annealed TiO2 films. Finally the samples were physically and electrically characterized. Average crystallite sizes of the nanoparticles are 20 and 25 nm for acetic and hydrochloric acid respectively. The average current flow through the devices was extremely small which are around micro-to-nanoampere. It was found that the electrical conductivity increased significantly when particle sizes decreases.

Tunneling Effects and Electrical Conductivity of CNT Polymer Composites

2011 ◽  
Vol 1304 ◽  
Author(s):  
S. Xu ◽  
O. Rezvanian ◽  
K. Peters ◽  
M.A. Zikry
Keyword(s):  
Electrical Conductivity ◽  
Polymer Composites ◽  
Current Flow ◽  
Electron Tunneling ◽  
Search Algorithm ◽  
Matrix Material ◽  
Three Dimensional ◽  
Current Transport ◽  
Current Densities ◽  
Tunneling Distance

ABSTRACTA three-dimensional (3D) carbon nanotube (CNT) network computational model was developed to investigate the electrical conductivity and current flow in polymer composites with randomly dispersed CNTs. A search algorithm was developed to determine conductive paths for 3D CNT arrangements and to account for electron tunneling effects. Tunneled currents were obtained as a function of tunneling distance and matrix material. Several possible CNT conductive paths were obtained and finite-element representative volume elements (RVEs) were then used to predict current densities in different CNT arrangements. The predictions indicate that random CNT arrangements can be optimized for current transport.

scholarly journals Micro- and Nanostructured Polyaniline for Instant Identification of Metal Ions in Solution

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 231 ◽  
Author(s):  
Agnieszka Michalska ◽  
Sebastian Golczak ◽  
Krzysztof Langer ◽  
Jerzy Langer
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Current Flow ◽  
Integral Intensity ◽  
Ion Current ◽  
Organic Polymer ◽  
Self Assembled Monolayer ◽  
New Device ◽  
Concentration Of Ions ◽  
Easy Operation

The unique properties of nanomaterials enable the creation new analytical devices. Polyaniline (PANI) micro- and nanofiber network, freestanding in the gap between two gold microelectrodes, has been used in a new nanodetector for metal ions in solutions. The gold electrodes were modified with the aid of alkanethiols, forming a self-assembled monolayer (SAM), which is able to block the ion current flow, but also to interact with metal ions when specific functional molecules are incorporated into the layer. The electric field of the trapped metal ions induces change of the electrical conductivity of polyaniline nanofibers in vicinity. A small injected sample (75 μL) of a solution of salt (about 0.5 μg of salt) was enough to induce a reproducible change in the electrical conductivity of polyaniline nano-network, which was registered as a function of time within 10–20 s. The response was proportional to the concentration of ions. It also depends on properties of ions, e.g., the ionic radius, which allows for identification of metal ions by analyzing the parameters of the signal: the retention time (RT), half width (HW), amplitude (A) and integral intensity (INT). The advantage of the new device is the instant responsiveness and easy operation, but also the simple construction based on organic (polymer) technology. The system is “open”—when learned and calibrated adequately, other metal ions can be analyzed. The nanodetector can be used in cases where monitoring of the presence and concentration of metal ions is important.

Spoke electrodynamics

1984 ◽  
Vol 75 ◽  
pp. 549-550
Author(s):  
A. Acterberg ◽  
R. Blandford ◽  
P. Goldreich
Keyword(s):  
Electrical Conductivity ◽  
Current Flow ◽  
Surface Conductivity ◽  
Conductivity Tensor ◽  
Charged Dust ◽  
Dust Grains ◽  
Radial Spokes ◽  
Ultraviolet Photons ◽  
Solar Ultraviolet ◽  
Integral Surface

Electrons are ejected by solar ultraviolet photons from the illuminated parts of Saturn's rings. Consequently, these portions of the rings possess significant electrical conductivity. Wc evaluate the height integral surface conductivity tensor and show that the main contribution is provided by charged dust grains. The conductivity tensor is applied to estimate the pattern of current flow along the surface of the rings and between the rings and the planet's ionosphere. Mechanisms for elevating grains along nearly radial spokes are explored.

scholarly journals Application of independent-channel method for investigation of electrical conductivity of graphene-containing shungite.

2021 ◽  
Author(s):  
I.V. Antonets ◽  
◽  
E.A. Golubev ◽  
V.G. Shavrob ◽  
V.I. Shcheglov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Spatial Distribution ◽  
Current Flow ◽  
Specific Conductivity ◽  
Specific Electrical Conductivity ◽  
Parallel Connection ◽  
Raster Electron Microscopy ◽  
Current Flows

The independent channel method which is intended for the calculation of specific electrical conductivity of graphene-contained shungite is proposed and realized on practice. It is noted that the most important of shungite application is the creation of screen hawing large area which are able to block electromagnetic radiation in wide frequency range. The most important factor which determines the blocking properties of shungite is the specific electrical conductivity of its carbon part which is determined by the spatial distribution of carbon atoms. As a main method of carbon structure investigation is mentioned the high-resolution raster electron microscopy which allows from the surface of specimen to receive the card of distribution of graphene slides and graphene packets. The spatial factor which determines the shungite conductivity is large anisotropy of single graphene slide which reaches three orders and more in the cases along and across the slide. The proposed method independent channels takes into consideration the arbitrary orientation of graphene packets relatively to direction of current flow. As a basis of method is employing the card of carbon spatial distribution which is received by raster electron microscopy method. The card is divided by parallel channels which transverse dimension is near or slightly exceeds the typical dimension of graphene packet. The channels are divided to square blocks which sides are equal to width of channel. The whole resistance of channel is formed by the successive connection of individual resistances of blocks. The resistance of whole card is determined by parallel connection of channels or averaging of resistance of all channels and following filling the whole area of card. The first step of analysis is the determination of advantage orientation of slides inside of every blocks. On the basis of determined orientation the block is filled by periodic structure which period is equal to the width of graphene slide and neighbouring interval. As a parameter which determines the orientation is used the angle between advantage orientation of graphene slides and axis of current flow between contacts. Owing to symmetry of task in comparison of current direction the limited meanings of corner is 0 and 90 degree. It is established two principal different cases of orientation: first – when determining angle is less than 45 degree and second when this angle is more than 45 degree. In the first case the current flows along the stripe with large conductivity. In the second case the current flows across these stripes so as through the stripes with low conductivity. It is found the smooth dependence of block resistivity from the angle of strip orientation. For the characteristic of area which is filled graphene slides it is proposed the coefficient of filling which is determined by binary discretization method. On the basis of analysis of slides orientation and filling coefficients are calculated the resistance of individual blocks. The resistances of all channels of investigated card are proposed. By using two methods – parallel connection and averaging over all channels it is calculated the specific electrical resistance and specific electrical conductivity of material as a whole. It is found that the received values of specific conductivity exceed the determined in experiment value in several (to 10) times. For the coordination of calculated value with experimental value it is made the variation of specific resistances of graphene slides and intervals between its. It id found that the calculation by method of parallel connection of channels ensures several better coordination than method of averaging. It is shown that the resistance is improved in the first turn by the increasing the resistance of interval between slides. In the quality of possible reason of decisive role of interval it is proposed the observed in experiment sharp non-homogeneity of relative arrangement of graphene slides. It is discussed the possible courses of further development of work. As a most important task it is proposed the more circumstantial determination of statistical character of received results.

Resolving the spatial distribution of the true electrical conductivity with depth using EM38 and EM31 signal data and a laterally constrained inversion model

Soil Research ◽  
2010 ◽  
Vol 48 (5) ◽  
pp. 434 ◽  
Author(s):  
J. Triantafilis ◽  
F. A. Monteiro Santos
Keyword(s):  
Electrical Conductivity ◽  
Spatial Distribution ◽  
Vadose Zone ◽  
Root Zone ◽  
Joint Inversion ◽  
Geophysical Methods ◽  
Exchange Capacity ◽  
Saturated Soil ◽  
Cotton Field ◽  
Inversion Algorithm

The ability to map the spatial distribution of average soil property values using geophysical methods at the field and district level has been well described. This includes the use of electromagnetic (EM) instruments which measure bulk soil electrical conductivity (σa). However, soil is a 3-dimensional medium. In order to better represent the spatial distribution of soil properties with depth, various methods of inverting EM instrument data have been attempted and include Tikhonov regularisation and layered earth models. In this paper we employ a 1-D inversion algorithm with 2-D smoothness constraints to predict the true electrical conductivity (σ) using σa data collected along a transect in an irrigated cotton field in the lower Namoi valley. The primary σa data include the root-zone measuring EM38 and the vadose-zone sensing EM31, in the vertical (v) and horizontal (h) dipole modes and at heights of 0.2 and 1.0 m, respectively. In addition, we collected σa with the EM38 at heights of 0.4 and 0.6 m. In order to compare and contrast the value of the various σa data we carry out individual inversions of EM38v and EM38h collected at heights of 0.2, 0.4, and 0.6 m, and EM31v and EM31h at 1.0 m. In addition, we conduct joint inversions of various combinations of EM38 σa data available at various heights (e.g. 0.2 and 0.4 m). Last we conduct joint inversions of the EM38v and EM38h σa data at 0.2, 0.4, and 0.6 m with the EM31v and EM31h at 1.0 m. We find that the values of σ achieved along the transect studied represent the duplex nature of the soil. In general, the EM38v and EM38h collected at a height of 0.2, 0.4, and 0.6 m assist in resolving solum and root-zone variability of the cation exchange capacity (cmol(+)/kg of soil solids) and the electrical conductivity of a saturated soil paste extract (ECe, dS/m), while the use of the EM31v and EM31h at 1.0 m assists in characterising the vadose zone and the likely location of a shallow perched-water table. In terms of identifying an optimal set of EM σa data for inversion we found that a joint inversion of the EM38 at a height of 0.6 m and EM31 signal data provided the best correlation with electrical conductivity of a saturated soil paste (ECp, dS/m) and ECe (respectively, 0.81 and 0.77) closely followed by a joint inversion of all the EM38 and EM31 σa data available (0.77 and 0.56).

scholarly journals Estimating Soil Salinity from Saturated Soil-Paste Electrical Conductivity

1989 ◽  
Vol 53 (2) ◽  
pp. NP-NP ◽  
Author(s):  
J.D. Rhoades ◽  
Nahid A. Manteghi ◽  
P.J. Shouse ◽  
W.J. Alves
Keyword(s):  
Electrical Conductivity ◽  
Soil Salinity ◽  
Saturated Soil

Analysis of electrical conductivity imaging

Geophysics ◽  
1981 ◽  
Vol 46 (7) ◽  
pp. 1025-1036 ◽  
Author(s):  
K. A. Dines ◽  
R. J. Lytle
Keyword(s):  
Electrical Conductivity ◽  
Cross Section ◽  
Current Flow ◽  
Estimation Error ◽  
Low Frequency ◽  
Core Sample ◽  
Steady Current ◽  
Using Data ◽  
Conductivity Image ◽  
Computer Simulation Studies

We investigate the feasibility of imaging the electrical conductivity in a cross‐section of an object (such as a core sample) by numerical inversion of low‐frequency, electromagnetic (EM) boundary data. Current flow is assumed to be confined to the cross‐section, which is modeled as a network of resistors. The network serves as a discrete approximation of the distributed‐parameter system that is described mathematically by Maxwell’s equations for steady current flow in a nonhomogeneous medium. A complete set of linearly independent voltage vectors is applied to the peripheral nodes, and the resulting node currents serve as the measured data for estimating the internal conductivity pattern (image). We generate estimates of this conductivity image by using an iterative process on network equations that are linearized in the unknown conductance variables. The mathematical feasibility of this approach is demonstrated by computer simulation studies using data generated from the network model. Reconstructed images are presented for sample conductance patterns under both ideal and noisy data conditions. An error analysis is performed to relate data noise to image‐estimation error.

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