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Electrical Resistivity
Published in Alan J. Lutenegger, Laboratory Manual for Geotechnical Characterization of Fine-Grained Soils, 2023
A long length of copper wire has a higher resistance than a short length of the same diameter wire, but the resistivity of the copper is the same. Resistivity is the inverse of conductivity. If we say that a material, such as copper, has a very low resistivity, then it means that it has a high conductivity. The traditional units used for resistivity are Ωm or Ωcm (1 Ωm = 100 Ωcm). The Electrical Resistivity of soils ranges over four orders of magnitude, from about 1 Ωm to 5,000 Ωm.
In situ measurement of steel push-piles and helical piers in expansive soils
Published in N. Khalili, A.R. Russell, A. Khoshghalb, Unsaturated Soils: Research & Applications, 2020
J.D. Nelson, Z.P. Fox, E.J. Nelson
For the geophysical survey a probe, shown in Figure 3, was lowered into the hole. This probe utilized a conductivity meter to measure the conductivity of a volume of soil mass surrounding the hole. This volume of soil is a cylinder 0.9 m in diameter and 0.8 m in height centered on the middle of the tool and the borehole. The conductivity of this soil volume is measured in millisiemens/meter, the inverse of (kilo) ohm-meter, the measurement of resistivity. Conductivity measures the materials ability to conduct electricity. Because metals are 100 to 1000 times more conductive than most in situ earth materials, the presence of metals in the soil mass will have a significant influence on the conductivity of the soil volume being measured. If the metallic content within the measured volume is low, the effect on the conductivity measurement will be small. The probe was initially lowered to the bottom of the hole, and readings were taken as it was withdrawn. The tool was stopped at 300 mm intervals and the values of conductivity recorded in a field notebook.
Current, voltage and resistance
Published in Mike Tooley, Lloyd Dingle, Engineering Science, 2020
Conductivity is the ability of a material to convey an electric current. It is therefore the same as the reciprocal of the resistivity of the material. Hence: σ=1ρ
Effects of nematic liquid crystal doped with multi-walled carbon nanotube on electro-optic properties and electrostatic discharge immunity of liquid crystal display device
Published in Liquid Crystals, 2023
Zihan Ma, Yue Han, Zhiguang Li, Yanjun Zhang, Hui Zhang, Guili Zheng, Jianhui Zhang, Shouhong Liu
The fundamental parameter of final measurement is electrical conductivity. Conductivity refers to the ability of matter to conduct electricity, the greater the conductivity, the stronger the ability to conduct electricity. CNTs are composed of sp-bonded carbon (C) atoms arranged in honeycomb-like lattice sheets, with each C atom bonded to three other C atoms. C has four valence electrons but only three are used to form covalent bonds. Therefore, the fourth electron remains free to conduct electricity. That is why CNTs behave as semiconductors or conductors. The axial conductivity of CNTs was found to be very high, reaching 10 S/m [27], actual conductivity fluctuates by several magnitude due to the size or construction [28]. Therefore, it can be supposed that the introduction of CNTs into LCs can improve conductivity.
Physical, mechanical, and electrical properties of rice starch-based films plasticised by ionic liquid
Published in Indian Chemical Engineer, 2022
Joydev Roy, Suvendu Bhattacharya, Partha Pratim Sahu, Amit Baran Das
Electrical resistivity and conductivity are important properties of materials. Conductivity and resistivity are inversely proportional to each other; if conductivity is low, resistivity is high, and vice versa. The electrical properties of the films, such as resistivity and conductivity, changed dramatically (p ≤ 0.05) as the BMIMCl concentration increased. The resistivity and conductivity of the native starch film were 1649.2 Ωm and 0.000606 S/m, respectively, meaning that the native starch film had a negligible capacity for electrons to flow. With an increase in IL concentration, the film's resistivity decreased significantly, and a clear opposite trend in conductivity was observed (Table 2). The charge carrier concentration determines the conductivity of a film. When the concentration of BMIMCl was increased from 2 to 4%, the resistivity decreased from 7.3 to 3.4 Ωm but conductivity increased from 0.13 to 0.29 S/m. Zhang et al. [13] proposed a similar trend for [C2mim][OAc]-plasticised polymer films. According to Ning et al. [28] an increase in ion concentration could effectively boost the conductance of starch film due to increased ion mobility through the ion pair dissociation mechanism. Ning et al. [28] also suggested that the effect of water content on the conductance of film was evident. As a result, even though the film's strength is reduced, the developed film can be used as a primary packing of food in situations when in-pack cooking is required.
Optimization of ultrasound-assisted microemulsions of citral using biopolymers: characterization and antifungal activity
Published in Journal of Dispersion Science and Technology, 2022
Dulce María Miss-Zacarías, Maricarmen Iñiguez-Moreno, Montserrat Calderón-Santoyo, Juan Arturo Ragazzo-Sánchez
Conductivity is the ability of a material to conduct an electric current and depends on the interactions, the atomic structure, and temperature.[44] The conductivity of the tested emulsions ranged from 0.72 to 1.45 mS (Table 2). The conductivity shown the same behavior as the viscosity, it increased as a direct function of the biopolymer concentration. It has been reported that the conductivity increased with the increase of the biopolymer concentration in emulsions with AG.[45] However, in this research, the conductivity increased according to an increase in the concentration of anionic biopolymers, which might be due to the increment in the solids content. The total solids –mainly dissolved solids– had the greatest contribution to the conductivity.[46] Besides, the low conductivity values obtained in this research also can be attributed to the process of cavitation and ultrasonic homogenization that can cause ion aggregations, reducing the mobile ions of these systems and consequently the electrical conductivity.[47]