scholarly journals Numerical Modeling of the Effects of Electrode Spacing and Multilayered Concrete Resistivity on the Apparent Resistivity Measured Using Wenner Method

2020 ◽  
Author(s):  
Karthick Thiyagarajan ◽  
Parikshit Acharya ◽  
Lasitha Piyathilaka ◽  
sarath kodagoda
Keyword(s):  
Contact Area ◽  
Apparent Resistivity ◽  
Resistivity Measurement ◽  
Gaussian Process Regression ◽  
Electrode Spacing ◽  
Electrical Resistivity Measurement ◽  
Resistivity Measurements ◽  
Electrode Contact ◽  
Concrete Resistivity ◽  
Moisture Conditions

Smart Sensing technologies can play an important role in the conditional assessment of concrete sewer pipe linings. In the long-term, the permeation of acids can deteriorate the pipe linings. Currently, there are no proven sensors available to non-invasively estimate the depth of acid permeation in real-time. The electrical resistivity measurement on the surface of the linings can indicate the sub-surface acid moisture conditions. In this study, we consider acid permeated linings as a two resistivity layer concrete sample, where the top resistivity layer is assumed to be acid permeated and the bottom resistivity layer indicates normal moisture conditions. Firstly, we modeled the sensor based on the four-probe Wenner method. The measurements of the developed model were compared with the previous studies for validation. Then, the sensor model was utilized to study the effects of electrode contact area, electrode spacing distance and two resistivity layered concrete on the apparent resistivity measurements. All the simulations were carried out by varying the thickness of top resistivity layer concrete. The simulation study indicated that the electrode contact area has very minimal effects on apparent resistivity measurements. Also, an increase in apparent resistivity measurements was observed when there is an increase in the distance of the electrode spacing. Further, a machine learning approach using Gaussian process regression modeling was formulated to estimate the depth of acid permeated layer

scholarly journals Numerical Modeling of the Effects of Electrode Spacing and Multilayered Concrete Resistivity on the Apparent Resistivity Measured Using Wenner Method

2020 ◽  
Author(s):  
Karthick Thiyagarajan ◽  
Parikshit Acharya ◽  
Lasitha Piyathilaka ◽  
sarath kodagoda
Keyword(s):  
Contact Area ◽  
Apparent Resistivity ◽  
Resistivity Measurement ◽  
Gaussian Process Regression ◽  
Electrode Spacing ◽  
Electrical Resistivity Measurement ◽  
Resistivity Measurements ◽  
Electrode Contact ◽  
Concrete Resistivity ◽  
Moisture Conditions

Smart Sensing technologies can play an important role in the conditional assessment of concrete sewer pipe linings. In the long-term, the permeation of acids can deteriorate the pipe linings. Currently, there are no proven sensors available to non-invasively estimate the depth of acid permeation in real-time. The electrical resistivity measurement on the surface of the linings can indicate the sub-surface acid moisture conditions. In this study, we consider acid permeated linings as a two resistivity layer concrete sample, where the top resistivity layer is assumed to be acid permeated and the bottom resistivity layer indicates normal moisture conditions. Firstly, we modeled the sensor based on the four-probe Wenner method. The measurements of the developed model were compared with the previous studies for validation. Then, the sensor model was utilized to study the effects of electrode contact area, electrode spacing distance and two resistivity layered concrete on the apparent resistivity measurements. All the simulations were carried out by varying the thickness of top resistivity layer concrete. The simulation study indicated that the electrode contact area has very minimal effects on apparent resistivity measurements. Also, an increase in apparent resistivity measurements was observed when there is an increase in the distance of the electrode spacing. Further, a machine learning approach using Gaussian process regression modeling was formulated to estimate the depth of acid permeated layer

scholarly journals Theoretical Study on Geometries of Electrodes in Laboratory Electrical Resistivity Measurement

2019 ◽  
Vol 9 (19) ◽  
pp. 4167 ◽  
Author(s):  
Hong ◽  
Chong ◽  
Cho
Keyword(s):  
Electrical Resistivity ◽  
Multiple Scales ◽  
Design Method ◽  
Resistivity Measurement ◽  
Experimental Tests ◽  
Field Resistance ◽  
Electrode Spacing ◽  
Electrical Resistivity Measurement ◽  
Resistivity Measurements ◽  
Complementary Study

Electrical resistivity tests have been widely conducted in multiple scales, from a few centimeters to kilometers. While electrode spacing is used to define field resistance, laboratory measurements in a limited space need to consider electrode geometry. However, there are no studies that theoretically explore the effects of the geometries of electrodes and container size on laboratory electrical resistivity measurements. This study formulates a theoretical electrical resistance for the geometry of cylindrical electrodes and the size of a non-conductive container with the method of image charges. As a complementary study, experimental tests were conducted to verify the derived equations. The discussion includes the concepts of the spherical equivalent electrodes and a simple design method for container size.

scholarly journals Tracing Microalloy Precipitation in Nb-Ti HSLA Steel During Austenite Conditioning

2020 ◽  
Author(s):  
Johannes Webel ◽  
Adrian Herges ◽  
Dominik Britz ◽  
Eric Detemple ◽  
Volker Flaxa ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Ion Beam ◽  
Hsla Steel ◽  
Isothermal Holding ◽  
Resistivity Measurement ◽  
Hot Working ◽  
Electrical Resistivity Measurement ◽  
Steel Matrix ◽  
Finished Steel ◽  
Resistivity Measurements

Microalloying of low carbon steel with niobium (Nb) and titanium (Ti) is standardly applied in high-strength low-alloy (HSLA) steels enabling austenite conditioning during thermo-mechanical controlled processing (TMCP), which results in pronounced grain refinement in the finished steel. The metallurgical effects of microalloying elements are related solute drag and precipitate particle pinning, both acting on the austenite grain boundary thereby delaying or suppressing recrystallization of the deformed grain. In that respect it is important to better understand the precipitation kinetics as well as the precipitation sequence in a typical Nb-Ti-microalloyed steel. Various characterization methods have been utilized in this study for tracing microalloy precipitation after simulating different austenite TMCP conditions in a Gleeble apparatus. Atom probe tomography (APT), scanning transmission electron microscopy in a focused ion beam equipped scanning electron microscope (STEM-on-FIB) and electrical resistivity measurements provide complementary information on the precipitation status and are correlated with each other. It will be demonstrated that accurate electrical resistivity measurements can monitor the general consumption of solute microalloys (Nb) during hot working which was complemented by APT measurements of the steel matrix. On the other hand, STEM revealed that a large part of Nb-containing particles during hot working are co-precipitated with titanium during cooling from the austenitizing temperature. Precipitates that form during cooling or isothermal holding can be distinguished from strain-induced precipitates by corroborating STEM measurements with APT results. APT specifically allows obtaining detailed information about the chemical composition of precipitates as well as the distribution of elements inside the particle. Electrical resistivity measurement, on the contrary, provides macroscopic information on the progress of precipitation and can be calibrated by APT. The current paper highlights the complementarity of these methods and shows first results within the framework of a larger study on strain-induced precipitation.

scholarly journals Sensors for Monitoring Corrosion of Steel Embedded in Concrete

2020 ◽  
Author(s):  
Udaya B. Halabe ◽  
Jonas Kavi ◽  
Hota V. S. GangaRao
Keyword(s):  
Humidity Sensor ◽  
Low Cost ◽  
Resistivity Measurement ◽  
Ease Of Use ◽  
Electrical Resistivity Measurement ◽  
Reinforcing Bars ◽  
Concrete Members ◽  
Parking Garages ◽  
Concrete Resistivity ◽  
Corrosion Of Steel

This paper presents the use of an innovative low cost sensor for monitoring corrosion of steel membersembedded in concrete. Corrosion of steel reinforcing bars or embedded steel in concrete structuralcomponents is a major concern for structures such as bridges and parking garages. Moisture andchloride ingress through the cracks is the primary reason for corrosion of such concrete structures. Thechloride and moisture levels significantly affect the electrical conductivity of concrete. A low cost sensorfor measuring concrete resistivity (or conductivity) was developed by researchers at West VirginiaUniversity. This sensor is very durable and can be embedded in concrete members (beams, columns,etc.) at the time of pouring concrete. The electrical resistivity measurement obtained using this sensorcan be used to evaluate the potential for corrosion of embedded steel. This paper presents laboratoryand field results obtained using the sensor to demonstrate its usefulness. The paper also highlights thesimplicity and ease of use of this sensor. In addition, the paper also discusses the use of acommercially available temperature/humidity sensor that can be used in conjunction with the electricalresistivity sensor for a comprehensive assessment of the potential for corrosion of steel embedded inconcrete.

The Reconstructive Crystal Structure and the Exchange Energy

2006 ◽  
Vol 966 ◽  
Author(s):  
Ahmad Yazdani ◽  
Reza Osati Araghi ◽  
Farid Arya
Keyword(s):  
Electrical Resistivity ◽  
Magnetic Transition ◽  
Resistivity Measurement ◽  
Stable State ◽  
Electrical Resistivity Measurement ◽  
X Ray ◽  
Resistivity Measurements ◽  
Pattern Change ◽  
Field Independent

ABSTRACTIn order to describe the role of temperature variation on suppress of broad range of magnetic transition, the effect of annealing on different samples of a Gd-based intermetallic compound (i.e., Gd2Au) is investigated. The X-ray, AC and D.C susceptibility and electrical resistivity measurements for different annealed samples revealed that: (i) A great exchange dispersion is observed in A.C susceptibility (ii) This unstable exchange can be stabilized at certain annealing temperature, where the short rang unstable Ferromagnetic (F.M) breaks down or even changes to an Antiferromagnetic (AF.M) stable state. (iii) The DC susceptibility shows a spin-glass like transition temperature at TN= 61 K, above which the compound exhibits a completely paramagnetic (P.M) behavior and is field independent. (iv) the iso-termal magnetization does not follow the field induced transition (F.I.T) and behaves completely as a paramagnet which is independent of the field up to the highest available fields. The electrical resistivity measurement shows: a) A pronounced sharp bend at TN=61 K is manifested in ρ(T). b)some strong peak of X-ray pattern change into double adjacent lines in some intervals of low temperatures

scholarly journals Effect of Chloride on Electrical Resistivity in Carbonated and Non-Carbonated Concrete

2020 ◽  
Vol 10 (18) ◽  
pp. 6272 ◽  
Author(s):  
In-Seok Yoon ◽  
Chun-Ho Chang
Keyword(s):  
Electrical Resistivity ◽  
Resistivity Measurement ◽  
Chloride Concentration ◽  
Corrosion Damage ◽  
Chloride Ions ◽  
Chloride Penetration ◽  
Electrical Resistivity Measurement ◽  
Concrete Resistivity ◽  
Pore Liquid ◽  
The Relationship

The resistivity of a concrete structure exposed to chloride ions indicates the risk of early corrosion damage, because a low resistivity is related to rapid chloride penetration and to a high corrosion rate. Concrete resistivity is a geometry-independent material property that describes the electrical resistance, which is the ratio between the applied voltage and resulting current in a unit cell. The current is carried by ions dissolved in the pore liquid. While some data exist on the relationship between the moisture content and electrical resistivity of concrete, very little research has been conducted to evaluate the effect of chloride on the conduction of electricity through carbonated and non-carbonated concrete. The purpose of this study is to examine the effect of chloride concentration on the surface electrical resistivity measurement of carbonated and non-carbonated concrete. Chloride concentration had influenced the resistivity of concrete and the relationship showed a linear function. However, for concrete under the combined deterioration of carbonation and chlorides, a reduction in porosity due to the carbonation had a greater effect on the electrical resistivity than the increase in conductivity due to the chloride ions. Conclusively, this paper suggested the quantitative solution to depict the electrical resistivity of concrete with various chloride concentrations.

scholarly journals Selection of electrodes for the ˝in situ˝ electrical resistivity measurements of molten aluminium

2013 ◽  
Vol 49 (3) ◽  
pp. 279-283 ◽  
Author(s):  
M. Petric ◽  
S. Kastelic ◽  
P. Mrvar
Keyword(s):  
Electrical Resistivity ◽  
Contact Resistance ◽  
Electrode Material ◽  
Aluminium Alloys ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
Measuring Cell ◽  
Resistivity Measurements ◽  
Selection Of

The aim of this paper is the selections of proper electrode material for four-probe technique electrical resistivity measurement of aluminium and aluminium alloys. The biggest problem of electrodes is oxidation during measurement causing high contact resistance and giving wrong results. Various materials have been tested and aluminium electrodes have been chosen. Advantage of aluminium electrodes is that they are melted in specimen right after the pouring and causing no interface which is resulting with any contact resistance. The device together with measuring cell for ?in situ? measurement of electrical resistivity was developed using four-probe DC technique.

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