Radar sounding in potash mines, Saskatchewan, Canada

Geophysics ◽  
1988 ◽  
Vol 53 (12) ◽  
pp. 1556-1564 ◽  
Author(s):  
A. P. Annan ◽  
J. L. Davis ◽  
D. Gendzwill
Keyword(s):  
Electrical Conductivity ◽  
Clay Content ◽  
Stress Relief ◽  
Radar System ◽  
Signal Attenuation ◽  
Depth Of Penetration ◽  
Radio Signals ◽  
Frequency Properties ◽  
Antenna Systems

Dry salt has a very low electrical conductivity which permits radio signals to be transmitted through substantial thicknesses of salt with little attenuation. Radar sounding experiments conducted in several potash mines in Saskatchewan, Canada, confirm that radar is an effective method for probing salt environments. The experiments had two main objectives: namely, to assess the utility of impulse radar for mapping stratigraphy in the salt beds above, below, and beside mining tunnels and to determine the electrical character of the potash beds in situ, since little information was available on the radio‐frequency properties of potash ore. The experiments were conducted with an impulse radar system using antennas which radiated pulses having center frequencies between 100 and 1000 MHz. The higher frequency antennas detected thin clay beds and stress‐relief cracks to depths of several meters. Sounding for deeper structure known to exist at ranges of several tens of meters was not always successful. The lower frequency antenna systems were found most useful for deeper sounding; in some instances known geologic horizons were detected at depths of up to 20 m. Deeper structure was frequently masked by shallow, high‐reflectivity stress‐relief cracks. The potash deposits were found to have a bulk dielectric constant in the range 5 to 6. In many areas, the evaporites have a significant clay content which governed the signal attenuation. Depth of penetration of the radar was generally greater in areas of lower clay content.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Chemically reduced graphene oxide-coated knitted fabric imparted conductivity and outstanding hydrophobicity

2021 ◽  
pp. 004051752199547
Author(s):  
Min Hou ◽  
Xinghua Hong ◽  
Yanjun Tang ◽  
Zimin Jin ◽  
Chengyan Zhu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Knitted Fabric ◽  
Mesh Structure ◽  
Reduced Graphene ◽  
Chemically Reduced Graphene Oxide ◽  
Modified Hummers Method

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.

A highly sensitive chlorine gas sensor and enhanced thermal DC electrical conductivity from polypyrrole/silicon carbide nanocomposites

RSC Advances ◽  
2016 ◽  
Vol 6 (87) ◽  
pp. 84200-84208 ◽  
Author(s):  
Adil Sultan ◽  
Sharique Ahmad ◽  
Faiz Mohammad
Keyword(s):  
Electrical Conductivity ◽  
Silicon Carbide ◽  
Gas Sensor ◽  
Dodecylbenzenesulfonic Acid ◽  
Chemical Polymerization ◽  
Dc Electrical Conductivity ◽  
Highly Sensitive ◽  
Chlorine Gas

We report the synthesis of polypyrrole (PPy) and polypyrrole/silicon carbide nanocomposites (PPy/SiC) and PPy/SiC/dodecylbenzenesulfonic acid (DBSA) by in situ chemical polymerization and their application as sensors for the detection of highly toxic chlorine gas.

scholarly journals Preparation and Thermoelectric Properties of Graphite/poly(3,4-ethyenedioxythiophene) Nanocomposites

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2849 ◽  
Author(s):  
Yong Du ◽  
Haixia Li ◽  
Xuechen Jia ◽  
Yunchen Dou ◽  
Jiayue Xu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Power Factor ◽  
Oxidative Polymerization ◽  
Polymerization Process ◽  
Measurement Temperature ◽  
Temperature Range ◽  
Different Content

Graphite/poly(3,4-ethyenedioxythiophene) (PEDOT) nanocomposites were prepared by an in-situ oxidative polymerization process. The electrical conductivity and Seebeck coefficient of the graphite/PEDOT nanocomposites with different content of graphite were measured in the temperature range from 300 K to 380 K. The results show that as the content of graphite increased from 0 to 37.2 wt %, the electrical conductivity of the nanocomposites increased sharply from 3.6 S/cm to 80.1 S/cm, while the Seebeck coefficient kept almost the same value (in the range between 12.0 μV/K to 15.1 μV/K) at 300 K, which lead to an increased power factor. The Seebeck coefficient of the nanocomposites increased from 300 K to 380 K, while the electrical conductivity did not substantially depend on the measurement temperature. As a result, a power factor of 3.2 μWm−1 K−2 at 380 K was obtained for the nanocomposites with 37.2 wt % graphite.

scholarly journals Using Multivariate Geostatistics to Assess Patterns of Spatial Dependence of Apparent Soil Electrical Conductivity and Selected Soil Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Glécio Machado Siqueira ◽  
Jorge Dafonte Dafonte ◽  
Montserrat Valcárcel Armesto ◽  
Ênio Farias França e Silva
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Clay Content ◽  
Data Sets ◽  
Soil Electrical Conductivity ◽  
Multivariate Geostatistics ◽  
Northwestern Spain

The apparent soil electrical conductivity (ECa) was continuously recorded in three successive dates using electromagnetic induction in horizontal (ECa-H) and vertical (ECa-V) dipole modes at a 6 ha plot located in Northwestern Spain. One of the ECadata sets was used to devise an optimized sampling scheme consisting of 40 points. Soil was sampled at the 0.0–0.3 m depth, in these 40 points, and analyzed for sand, silt, and clay content; gravimetric water content; and electrical conductivity of saturated soil paste. Coefficients of correlation between ECaand gravimetric soil water content (0.685 for ECa-V and 0.649 for ECa-H) were higher than those between ECaand clay content (ranging from 0.197 to 0.495, when different ECarecording dates were taken into account). Ordinary and universal kriging have been used to assess the patterns of spatial variability of the ECadata sets recorded at successive dates and the analyzed soil properties. Ordinary and universal cokriging methods have improved the estimation of gravimetric soil water content using the data of ECaas secondary variable with respect to the use of ordinary kriging.

Semi-Electrical Conductivity of Gelcast Alumina Sintered under Nitrogen Atmosphere

2006 ◽  
Vol 11-12 ◽  
pp. 493-496 ◽  
Author(s):  
Ruben L. Menchavez ◽  
Koichiro Adachi ◽  
Masayoshi Fuji ◽  
Minoru Takahashi
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistance ◽  
Sintered Sample ◽  
Carbon Composite ◽  
Nitrogen Atmosphere ◽  
Potential Candidate ◽  
Nitrogen Gas ◽  
Conductive Property ◽  
Carbon Network

This work demonstrated an in-situ pyrolysis of gelcast alumina under reduction sintering to make alumina and carbon composite in providing semi-electrical conductivity. To increase the carbon content, the monomer was varied in the premix solution with reduction sintering in nitrogen gas. Two-probe method was used to measure electrical resistance of the sintered samples. The results revealed that the increase of monomer addition and sintering treatment were effective in reducing electrical resistance. The lowest value was 3.6×106-cm, which is a potential candidate for electrostatic shielding application. The reduction-sintered sample was re-sintered in an air in order to gain insight on the conductive path due to carbon network. Further tests such as XRD, TGA/DTA, and scanning electron microscopywere used to explain the semi-conductive property of the material.

Measuring transient solute transport through the vadoze zone using time domain reflectometry

Soil Research ◽  
2001 ◽  
Vol 39 (6) ◽  
pp. 1359 ◽  
Author(s):  
I. Vogeler ◽  
S. Green ◽  
A. Nadler ◽  
C. Duwig
Keyword(s):  
Electrical Conductivity ◽  
Solute Transport ◽  
Time Domain ◽  
Deterministic Model ◽  
Soil Surface ◽  
Time Domain Reflectometry ◽  
Richards Equation ◽  
Electrical Conductivities ◽  
Destructive Measurement

Time domain reflectometry (TDR) was used to monitor the transport of conservative tracers in the field under transient water flow in a controlled experiment under a kiwifruit vine. A mixed pulse of chloride and bromide was applied to the soil surface of a 16 m2 plot that had been isolated from the surrounding orchard soil. The movement of this solute pulse was monitored by TDR. A total of 63 TDR probes were installed into the plot for daily measurements of both the volumetric water content (θ) and the bulk soil electrical conductivity (σa). These TDR-measured σa were converted into pore water electrical conductivities (σw) and solute concentrations using various θ–σa–σw relationships that were established in the laboratory on repacked soil. The depth-wise field TDR measurements were compared with destructive measurement of the solute concentrations at the end of the experiment. These results were also compared with predictions using a deterministic model of water and solute transport based on Richards’ equation, and the convection–dispersion equation. TDR was found to give a good indication of the shape of the solute profile with depth, but the concentration of solute was under- or over-estimated by up to 50%, depending on the θ–σa–σw relationships used. Thus TDR can be used to monitor in situ transport of contaminants. However, only rough estimates of the electrical conductivity of the soil solution can so far be obtained by TDR.

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