Fehling’s test is a chemical test to detect reducing sugars and aldehydes in a solution, devised by the German chemist Hermann Christian von Fehling (1812-1885). Fehling’s solution consists of Fehling’s A (copper(II) sulphate solution) and Fehling’s B (sodium tartarate solution), equal amounts of which are added to the test solution. After boiling, a positive result is indicated by the formation of a brick-red precipitate of copper(I) oxide. Methanal, being a strong reducing agent, also produces copper metal; ketones do not react. The test is now rarely used, having been replaced by Benedict’s test.
Accelerated corrosion test is method designed to approximate, in a short time, the deteriorating effect under normal long-term service conditions.
Salt fog test is an accelerated corrosion test in which specimens are exposed to a fine mist of a solution usually containing sodium chloride (typically 5 %). Other contaminants can be added according to desired conditions. It is mainly used to determine the effectiveness of material finishes and protective coatings on materials. Salt-fog testing is also used to determine the effects of salt deposits on the electrical functions of electronic assemblies.
Organoleptic testing of matter is a testing of matter and material using the senses of sight, smell, taste and touch, used usually when buying groceries.
Anisotropic crystal is a crystal that exhibits different properties when tested along axes in different directions.
Autoignition temperature is the minimum temperature required to initiate or cause self-sustained combustion in any substance in the absence of a spark or flame. This varies with the test method.
Automatic burette is used for series of tests. It is connected with a bottle which contains the titration solution. The air is pumped into the bottle by a small rubber air pump, created the pressure in the bottle which the rises the solution to the top of burette. When the the burette is full, the valve is released, the pressure in the bottle falls and the burette automatically sets itself to zero. Work with automatic burettes is by far faster and the consumption of standard solution is smaller.
The magnetic field B due to a current-carrying conductor can be determined by Biot-Savart law. The contribution to magnetic field set up at distance r by the current element IdL is given by expression:
where μ0 is permeability constant. It plays a role in magnetic problems equivalent to the role of permittivity constant μ0 in electrostatics problems. In order to obtain B, contributions of all current elements have to be integrated. In case of a long straight conductor, carrying current I, Biot-Savart law gives:
SI unit for magnetic field B is tesla (T).
Permaeability constant μ0 has value 4π×10-7 T m A-1.
Ductility is a measure of a material’s ability to undergo appreciable plastic deformation before fracture; it may be expressed as percent elongation or percent area reduction from a tensile test.
Generalic, Eni. "Fehling%E2%80%99s test." Croatian-English Chemistry Dictionary & Glossary. 29 June 2022. KTF-Split. {Date of access}. <https://glossary.periodni.com>.
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