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  2. Law of definite proportions - Wikipedia

    en.wikipedia.org/wiki/Law_of_definite_proportions

    The law of definite proportion was given by Joseph Proust in 1797. [2]I shall conclude by deducing from these experiments the principle I have established at the commencement of this memoir, viz. that iron like many other metals is subject to the law of nature which presides at every true combination, that is to say, that it unites with two constant proportions of oxygen.

  3. Unified numbering system - Wikipedia

    en.wikipedia.org/wiki/Unified_numbering_system

    The Unified Numbering System for Metals and Alloys (UNS) is an alloy designation system widely accepted in North America.Each UNS number relates to a specific metal or alloy and defines its specific chemical composition, or in some cases a specific mechanical or physical property.

  4. Engineering drawing abbreviations and symbols - Wikipedia

    en.wikipedia.org/wiki/Engineering_drawing...

    A general note applies generally and is not called out with flags. 2. Find number: "FN" meaning "find number" refers to the ordinal number that gives an ID tag to one of the constituents in a parts list (list of materials, bill of materials). Thus "fasten using FN7" refers to a fastener that is "find number" 7 in the list. FoS: feature of size

  5. Iron - Wikipedia

    en.wikipedia.org/wiki/Iron

    Iron-carbon phase diagram. α-Iron is a fairly soft metal that can dissolve only a small concentration of carbon (no more than 0.021% by mass at 910 °C). [134] Austenite (γ-iron) is similarly soft and metallic but can dissolve considerably more carbon (as much as 2.04% by mass at 1146 °C).

  6. Density of states - Wikipedia

    en.wikipedia.org/wiki/Density_of_states

    The density of states related to volume V and N countable energy levels is defined as: = = (()). Because the smallest allowed change of momentum for a particle in a box of dimension and length is () = (/), the volume-related density of states for continuous energy levels is obtained in the limit as ():= (()), Here, is the spatial dimension of the considered system and the wave vector.

  7. History of atomic theory - Wikipedia

    en.wikipedia.org/wiki/History_of_atomic_theory

    The other iron oxide is a red powder, which Dalton referred to as "the intermediate or red oxide of iron" which is 70.4% iron and 29.6% oxygen. Adjusting these figures, in the black powder there is about 28 g of oxygen for every 100 g of iron, and in the red powder there is about 42 g of oxygen for every 100 g of iron. 28 and 42 form a ratio of ...

  8. (α/Fe) versus (Fe/H) diagram - Wikipedia

    en.wikipedia.org/wiki/(α/Fe)_versus_(Fe/H)_diagram

    The [α/Fe] versus [Fe/H] diagram is a type of graph commonly used in stellar and galactic astrophysics. It shows the logarithmic ratio number densities of diagnostic elements in stellar atmospheres compared to the solar value. The x-axis represents the abundance of iron (Fe) vs. hydrogen (H), that is, [Fe/H].

  9. Oxidation state - Wikipedia

    en.wikipedia.org/wiki/Oxidation_state

    The −1 occurs because each carbon is bonded to one hydrogen atom (a less electronegative element), and the − ⁠ 1 / 5 ⁠ because the total ionic charge of −1 is divided among five equivalent carbons. Again this can be described as a resonance hybrid of five equivalent structures, each having four carbons with oxidation state −1 and ...