The parathyroids produce a hormone called parathyroid hormone (PTH). PTHPTH-parathyroid hormone raises the blood calcium level by: 1  breaking down the bone (where most of the body's calcium is stored) and causing calcium release. 2  increasing the body's ability to absorb calcium from food.THPTH-parathyroid hormone raises the blood calcium level by: 1  breaking down the bone (where most of the body's calcium is stored) and causing calcium release. 2  increasing the body's ability to absorb calcium from food.
DN = Diameter Nominal. The term Diameter Nominal refers to the internal diameter of a pipe. Together with the nominal pressure rating and the materials class, all dimensions of a piping line, e. g. flange dimensions, are defined by indicating the nominal diameter. Steel is often not specified, but assumed as material.
Re: Mill Tolerance. Mill tolerance is the deviation allowed to a pipe manufacturer from the actual nominal thickness of a pipe. 1) This has been considered by relevant pipes ASTM standards, ASME B31 codes, and ASME B36.10 due to incapability of any mill to produce a pipe with an exact nominal thickness defined. The value in all the mentioned standards has been set to 12.5% of nominal thickness. 2) Both positive or negative mill tolerances can exist in a pipe. Positive would not be causing any significant impact but negative may put you in an odd situation if you didn't consider mill tolerance during piping thickness calculation.