Search results
Results from the WOW.Com Content Network
Simplified Acquisition Procedures (SAP) are a set of streamlined procedures for government procurement in the United States that reduce the administrative burden of awarding procurements below a threshold value, which, as of 2023, is $250,000. [1] The procedures are described in 48 CFR 13.
In electromagnetism, current density is the amount of charge per unit time that flows through a unit area of a chosen cross section. [1] The current density vector is defined as a vector whose magnitude is the electric current per cross-sectional area at a given point in space, its direction being that of the motion of the positive charges at this point.
Certified cost or pricing data may not be obtained for acquisitions at or below the simplified acquisition threshold. [3] Other exceptions are stated in FAR 15.403-1(b) or may be adopted under a waiver requested by the contracting officer in exceptional circumstances. If certified cost or pricing data has been requested by the Government and ...
The electric current density J A equals the charge q A of the ion multiplied by the flux j A = Current density has units of (Amperes/m 2). Molar flux has units of (mol/(s m 2)). Thus, to get current density from molar flux one needs to multiply by Faraday's constant F (Coulombs/mol).
For electrons, the current density J (amperes per meter squared) is written: = = /. where is the anode current and S the surface area of the anode receiving the current; is the magnitude of the charge of the electron and is its mass. The equation is also known as the "three-halves-power law" or the Child–Langmuir law.
The two most significant results of the Drude model are an electronic equation of motion, = (+ ) , and a linear relationship between current density J and electric field E, =. Here t is the time, p is the average momentum per electron and q, n, m , and τ are respectively the electron charge, number density, mass, and mean free time between ...
Since both the voltage and the concentration gradients influence the movement of ions, this process is a simplified version of electrodiffusion. Electrodiffusion is most accurately defined by the Nernst–Planck equation and the GHK flux equation is a solution to the Nernst–Planck equation with the assumptions listed below.
The Tafel equation describes the dependence of current for an electrolytic process to overpotential. The exchange current density is the current in the absence of net electrolysis and at zero overpotential. The exchange current can be thought of as a background current to which the net current observed at various overpotentials is normalized.