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Power Distribution Fundamentals
Published in Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo, Electrical Power Systems Technology, 2021
Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo
The resistance of a conductor expresses the amount of opposition it will offer to the flow of electrical current. The unit of measurement for resistance is the ohm (Ω). The resistivity (p) of a conductor is the resistance for a specified cross-sectional area and length. This measurement is given in circular mil-feet (cmil-ft). The resistivity of a conductor changes with the temperature; so resistivity is usually specified at a temperature of 20°C. The resistivity for some common types of conductors is listed in Table 8-2.
Power Distribution Fundamentals
Published in Stephen W. Fardo, Dale R. Patrick, Electrical Power Systems Technology, 2020
Stephen W. Fardo, Dale R. Patrick
The resistance of a conductor expresses the amount of opposition it will offer to the flow of electrical current. The unit of measurement for resistance is the ohm (Ω). The resistivity (p) of a conductor is the resistance for a specified cross-sectional area and length. This measurement is given in circular mil-feet (cmil-ft). The resistivity of a conductor changes with the temperature, so resistivity is usually specified at a temperature of 20° Celsius. The resistivity for some common types of conductors is listed in Table 8-2.
Energy, Environment, and Renewable Energy
Published in Radian Belu, Fundamentals and Source Characteristics of Renewable Energy Systems, 2019
Current is measured in amperes (A), voltage in volts (V), and resistance in ohms (Ω). When the V and I are expressed in volts and amperes, P is expressed in watts. From Equation (1.4), electrical energy in joule is power in watts multiplied by time in seconds. More often electrical energy is expressed in kilowatt-hours (kWh) by dividing energy in joules by a conversion factor 3.6 106 J/kWh. Energy can be transferred between systems in a variety of ways, such as the transmission of electromagnetic energy via photons, physical collisions which transfer kinetic energy, and the conductive transfer of thermal energy. Energy is strictly conserved and is also locally conserved wherever it can be defined. Classical mechanics distinguishes between kinetic energy, which is determined by an object’s movement through space, and potential energy, which is a function of the position of an object within a field. Kinetic energy associated with moving objects defined for an object of mass, m, moving at velocity v, as: () E=12mv2
Medium-chain-length poly-3-hydroxyalkanoates-carbon nanotubes composite as proton exchange membrane in microbial fuel cell
Published in Chemical Engineering Communications, 2019
Hindatu Yusuf, M. Suffian M. Annuar, Syed Mohammad Daniel Syed Mohamed, Ramesh Subramaniam
A customized two-chambered glass MFC obtained from Adams and Chittenden Scientific Glass (Berkeley, CA) with a working volume of 100 mL was utilized throughout the experiments. The chambers were separated either by the PHA-MC membrane or Nafion 117 as the control. The anode chamber was charged with POME wastewater (100 mL) (Table 1). Due to the low electrolyte conductivity and high pH of the POME, it was supplemented with (g/L) 1.0 glucose, 10.7 K2HPO4, 5.3 K2HPO4 and 0.1% (v/v) trace element. 10% v/v of E. coli prepared as described in the preceding section was used as the biocatalyst. The anode chamber was sparged with nitrogen gas for 15 min before being sealed airtight. The catholyte was 100 ml of 50 mM [K3Fe(CN)6] supported by 100 mM PBS (pH 6.98) in deionized water. The cathode electrode was plain CC while the anode electrode was CC coated with polyethyleneglycol methacrylate-grafted mcl-PHA and composited with MC (detailed preparation method is provided in the Supplementary material). The area of each cathode- and anode electrode was 6 cm2. The MFC setup was incubated at 37 °C (Hotech incubator model 624, Hotech, Seoul, Korea) and operated in a fed-batch mode. The voltage was recorded across a 1 kΩ external resistor with the help of a digital multimeter (Rolson 27259). Polarization data were obtained by varying the resistors between 0.1 and 10 kΩ. Data obtained was used to calculate the current (I) and power density (PD) according to the following equations: where I is the current (ampere), V is the voltage (V), and R (ohm) is the resistance. where ASA is the anode surface area (cm2).