Electric currentAn electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net rate of flow of electric charge through a surface. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes.
Reactive nitrogen speciesReactive nitrogen species (RNS) are a family of antimicrobial molecules derived from nitric oxide (•NO) and superoxide (O2•−) produced via the enzymatic activity of inducible nitric oxide synthase 2 (NOS2) and NADPH oxidase respectively. NOS2 is expressed primarily in macrophages after induction by cytokines and microbial products, notably interferon-gamma (IFN-γ) and lipopolysaccharide (LPS). Reactive nitrogen species act together with reactive oxygen species (ROS) to damage cells, causing nitrosative stress.
Chromate and dichromateChromate salts contain the chromate anion, CrO42−. Dichromate salts contain the dichromate anion, Cr2O72−. They are oxyanions of chromium in the +6 oxidation state and are moderately strong oxidizing agents. In an aqueous solution, chromate and dichromate ions can be interconvertible. Potassium-chromate-sample.jpg|[[potassium chromate]] Potassium-dichromate-sample.jpg|[[potassium dichromate]] Chromates react with hydrogen peroxide, giving products in which peroxide, O22−, replaces one or more oxygen atoms.
Potassium dichromatePotassium dichromate, , is a common inorganic chemical reagent, most commonly used as an oxidizing agent in various laboratory and industrial applications. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health. It is a crystalline ionic solid with a very bright, red-orange color. The salt is popular in laboratories because it is not deliquescent, in contrast to the more industrially relevant salt sodium dichromate. Potassium dichromate is usually prepared by the reaction of potassium chloride on sodium dichromate.
Hall-effect thrusterIn spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters (based on the discovery by Edwin Hall) are sometimes referred to as Hall thrusters or Hall-current thrusters. Hall-effect thrusters use a magnetic field to limit the electrons' axial motion and then use them to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume.
