Studies of Changes in the Electrical Resistivity of Rocks of the Tashtagol Mine in a Critical Rock-bump Hazardous State Based on the Kinetic Concept of Solids Destruction

2020 ◽  
pp. 19-25
Author(s):  
K.Kh. Lee ◽  
◽  
V.V. Ivanov ◽  
Keyword(s):  
Mechanical Loading ◽  
Electrical Resistance ◽  
Specific Electrical Resistance ◽  
Iron Ores ◽  
Electric Resistance ◽  
Limit States ◽  
Specific Electric Resistance ◽  
Iron Ore Deposit ◽  
Tashtagol Mine ◽  
Host Rocks

Main hypotheses of the occurrence of seismic events centers, including rock bumps are presented. Equations of kinetic theory of strength are given. A two-stage kinetic model of crack accumulation and catastrophic destruction of rocks is formulated. It consists in the fact that at the first stage of the rock bump preparation there is a diffuse accumulation of cracks, and at the second — merging of cracks, appearance of enlarged cracks and formation of the destruction center. The results are presented concerning the theoretical and laboratory measurements of change of specific electric resistance of the host rocks and ores of iron ore deposit at mechanical loading and destruction. It has been shown that the relative change of specific electrical resistance of the low conductive rocks depends significantly on the ratio of electrical resistance of the rock itself and charged zones near the surface of the incipient cracks during rock loading. With the accumulation of cracks in the process of mechanical loading of the host rocks of the Tashtagol mine, the number of charged point defects of the structure on the crack edges increases. Specific electrical resistance of such rocks decreases with the accumulation of the number of cracks. In the ore bodies and magnetic iron ores, on the contrary, with increasing disturbance, the electrical resistance increases. There is regular change in the electrical resistance of rocks in the intermediate and limit states. For ores and magnetic iron ores, the critical change is 40 %, and for the host rocks with high electrical resistance — 28–37 %. Obtained values of change of the specific electric resistance in the rock critical state can be used for prediction of the rock bumps.

scholarly journals Toward Structural Health Monitoring of Civil Structures Based on Self-Sensing Concrete Nanocomposites: A Validation in a Reinforced-Concrete Beam

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Diego L. Castañeda-Saldarriaga ◽  
Joham Alvarez-Montoya ◽  
Vladimir Martínez-Tejada ◽  
Julián Sierra-Pérez
Keyword(s):  
Reinforced Concrete ◽  
Damage Detection ◽  
Direct Current ◽  
Health Monitoring ◽  
Electrical Resistance ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Structural Member ◽  
Rc Beam ◽  
Electric Resistance

AbstractSelf-sensing concrete materials, also known as smart concretes, are emerging as a promising technological development for the construction industry, where novel materials with the capability of providing information about the structural integrity while operating as a structural material are required. Despite progress in the field, there are issues related to the integration of these composites in full-scale structural members that need to be addressed before broad practical implementations. This article reports the manufacturing and multipurpose experimental characterization of a cement-based matrix (CBM) composite with carbon nanotube (CNT) inclusions and its integration inside a representative structural member. Methodologies based on current–voltage (I–V) curves, direct current (DC), and biphasic direct current (BDC) were used to study and characterize the electric resistance of the CNT/CBM composite. Their self-sensing behavior was studied using a compression test, while electric resistance measures were taken. To evaluate the damage detection capability, a CNT/CBM parallelepiped was embedded into a reinforced-concrete beam (RC beam) and tested under three-point bending. Principal finding includes the validation of the material’s piezoresistivity behavior and its suitability to be used as strain sensor. Also, test results showed that manufactured composites exhibit an Ohmic response. The embedded CNT/CBM material exhibited a dominant linear proportionality between electrical resistance values, load magnitude, and strain changes into the RC beam. Finally, a change in the global stiffness (associated with a damage occurrence on the beam) was successfully self-sensed using the manufactured sensor by means of the variation in the electrical resistance. These results demonstrate the potential of CNT/CBM composites to be used in real-world structural health monitoring (SHM) applications for damage detection by identifying changes in stiffness of the monitored structural member.

Forecasting Performance of Ceramic Cutting Tool

2017 ◽  
Vol 736 ◽  
pp. 86-90 ◽  
Author(s):  
Vyacheslav Maksarov ◽  
A. Khalimonenko
Keyword(s):  
Electrical Resistance ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Tool Material ◽  
Ceramic Materials ◽  
Specific Electrical Resistance ◽  
Testing Methods ◽  
Microstructural Parameters ◽  
Forecasting Performance ◽  
Nondestructive Testing Methods

The article considers the problems of forecasting the performance of cutting tools equipped with replaceable ceramic cutting bits. It is proposed to forecast the operability of ceramic tools on the ground of dependence between its performance characteristics and the microstructural parameters of the tool material. It is proposed to determine the parameters of ceramic bits microstructure by a nondestructive testing methods based on measuring the specific electrical resistance of ceramic materials. As a result of the study we have undertaken, a relationship was detected between the performance and specific electrical resistance of ceramic cutting tools.

scholarly journals A Method For Determination Of Specific Electrical Resistance Of Steel And Nano-Coating Sputtered On It

2015 ◽  
Vol 2 ◽  
pp. 118 ◽  
Author(s):  
Andris Martinovs ◽  
Josef Timmerberg ◽  
Konstantins Savkovs ◽  
Aleksandrs Urbahs ◽  
Paul Beckmann
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Permeability ◽  
Electrical Resistance ◽  
Skin Effect ◽  
Specific Electrical Resistance ◽  
Specific Electrical Conductivity ◽  
Relative Magnetic Permeability ◽  
Nano Coating ◽  
Cylindrical Steel

The paper describes methods developed to determine specific electrical conductivity and relative magnetic permeability of cylindrical steel items and nano-coatings deposited on them by sputtering. Research enables development of a new method for determination of thickness of vacuum deposited nano- coating that is based on application of skin effect.

Cross Property Correlations for Metals Subjected to Fatigue Damage Accumulation

2002 ◽  
Author(s):  
Mahesh C. Bogarapu ◽  
Igor Sevostianov
Keyword(s):  
Electrical Resistance ◽  
Damage Accumulation ◽  
Fatigue Tests ◽  
Electric Resistance ◽  
Metal Structures ◽  
Accumulated Damage ◽  
Fatigue Damage Accumulation ◽  
Theoretical Predictions ◽  
Method Of Evaluation ◽  
Better Than

A new method of evaluation of elastic property deterioration due to accumulated damage is suggested and experimentally verified. It is based on the explicit correlations between two groups of anisotropic properties – conductivity and elasticity, recently established for porous/microcracked materials with anisotropic microstructures. An experimental study of fatigue has been done to verify the theoretical predictions. The electrical resistance and Young’s modulus are measured as functions of the number of loading cycles in the standard fatigue tests. The agreement between the theoretical predictions and the direct experimental data is better than 10% in all cases. The results allow one to use the measurement of electric resistance to estimate the damage accumulated in metal structures and decrease in the elastic modulus.

Thermoelectric High Power Generating Module Made by n-Ba8AlxSi46-x Clathrate

2008 ◽  
Vol 1102 ◽  
Author(s):  
Shinji Munetoh ◽  
Makoto Arita ◽  
Hideki Makiyama ◽  
Teruaki Motooka
Keyword(s):  
Figure Of Merit ◽  
Open Circuit Voltage ◽  
Thermoelectric Module ◽  
Lithium Ion ◽  
Open Circuit ◽  
Electric Resistance ◽  
Thermoelectric Figure ◽  
Arc Melting ◽  
In Series ◽  
Specific Electric Resistance

AbstractWe have developed a new thermoelectric power-generating module composed of 72 pieces of n-type Ba8Al18Si28 clathrate elements made by arc melting. The Seebeck coefficient, specific electric resistance and thermal conductivity of Ba8Al18Si28 clathrate were 250 μV/K, 1.9 mΩcm and 3.1 W/mK at 500 °C, respectively, and the thermoelectric figure of merit (ZT) was 0.8. The new thermoelectric module was constructed using only n-type thermoelectric elements connected in series with hook-shaped electrodes. The open-circuit voltage of the module increased with hot-side temperature up to 1.8 V at 500 °C and generated 0.24 W. The module was successfully used to charge lithium-ion batteries for mobile phones.

Advisability of establishing norms for the specific electrical resistance of viscose textile yarns

1986 ◽  
Vol 18 (2) ◽  
pp. 122-123
Author(s):  
G. S. Khorovodnov ◽  
L. N. Panova ◽  
V. P. Lioznova ◽  
R. I. Lapshina ◽  
T. B. Androsova
Keyword(s):  
Electrical Resistance ◽  
Specific Electrical Resistance ◽  
Viscose Textile

scholarly journals Ultrahigh-Temperature Continuous Reactors Based on Electrothermal Fluidized Bed Concept

2015 ◽  
Vol 138 (4) ◽  
Author(s):  
Sergiy S. Fedorov ◽  
Upendra Singh Rohatgi ◽  
Igor V. Barsukov ◽  
Mykhailo V. Gubynskyi ◽  
Michelle G. Barsukov ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Electrical Resistance ◽  
Specific Electrical Resistance ◽  
Natural Graphite ◽  
Operating Variable ◽  
The Difference ◽  
Ultrahigh Temperature ◽  
Chaotic Nature ◽  
Functional Prototype ◽  
Dynamics Models

Authors introduce an ultrahigh-temperature (i.e., 2500–3000 °C) continuous fluidized bed furnace, in which the key operating variable is specific electrical resistance of the bed. A correlation has been established to predict the specific electrical resistance for the natural graphite-based precursors. Fluid dynamics models have been validated with the data from a fully functional prototype reactor. Data collected demonstrated that the difference between the calculated and measured values of specific resistance is approximately 25%; due to chaotic nature of electrothermal fluidized bed processes, this discrepancy was deemed acceptable. Optimizations proposed allow producing natural graphite-based end product with the purity level of 99.98 + wt. %C for battery markets.

scholarly journals The Specific Electrical Resistance of Frog's Muscle

1921 ◽  
Vol 15 (3) ◽  
pp. 379-382 ◽  
Author(s):  
William Hartree ◽  
Archibald Vivian Hill
Keyword(s):  
Electrical Resistance ◽  
Specific Electrical Resistance
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