Calibration vessel

Thirty millimoles of diborane(6) 4 is measured out on the vacuum line by expanding it into a calibrated vessel of at least 1 -L capacity and then is recondensed at -196°. Under static vacuum the diborane(6) is then distilled and condensed onto the methyllithium at -196°. 

Calibrated vessels with glass break-seals 81... 

An alternative to the use of small spherical phials, which often has advantages in terms of the flexibility of the apparatus, is the use of calibrated vessels or ampoules with break-seals. They consist usually of a tube 3-6 mm i.d. and 20-70 mm long with a calibration mark and carrying a fragile glass membrane which can be broken when desired, so as to admit the contents of the ampoule to a mixing vessel or reaction vessel. The construction of different types of magnetic break-seals has been described in Section 2.2.4.4. 

Karl-Fischer titration for total H 2O in original sample NH 3 in original sample by Kjeldahl distillation total N2 in original sample by decomposition and Kjeldahl distillation original sample extracted with a saturated NaCI solution in a calibrated vessel infrared spectrum of organic phase from 4 recorded... 

There are several British Standards that deal with liquid pyknometry applied to specific materials12-13-141516. A pyknometer bottle of up to 50 ml volume is usually sufficient for fine powders but coarse materials may require larger calibrated vessels. BS 1377 1975, for example, requires the use of a 1 litre cylindrical gas jar, closed by a ground plate, to measure the density of soils that contain particles coarser than 2 mm BS test sieve (but not coarser than 37.5 mm). 

For the preparation of pure chlorine, b.p. — 34.157760 mm., d 25 1.565, d 30 1.551, d 20 1.524, see reference 4a. It usually suffices to pass chlorine through two wash-bottles containing concentrated sulfuric acid and, if necessary, through a CaO tube for removal of HC1 and thereafter over phosphorus pentoxide to remove water. To provide measured amounts of chlorine it is convenient to liquify it in a calibrated vessel cooled in an acetone-C02 bath. Chlorine largely free from oxygen and oxides of chlorine can be obtained from manganese dioxide hydrate and concentrated hydrochloric acid.5 c... 

The measurement of oxygen uptake provides a direct index of metabolic rate this measurement can be done simply by placing experimental animals In a calibrated vessel maintained at constant temperature and connected to an oxygen analyzer (86). Repeatedly used as an Index of thyromimetic activity have been the in vitro assay of oxygen uptake by suspended mitochondria and the spectrophotometric assays of rat liver mitochondrial a-glycerophosphate dehydrogenase (87) and of cytoplasmic malic enzyme (88). 

Metering can be done either by weight using a balance, or by volume using a calibrated vessel, pipette, disposable syringe or an automatic mixing and metering device. 

If a large vessel (e.g. 50-100 L) is used for a preparation process, this may be carried out on a volume basis. In that case the volume is determined using a calibrated vessel with volume marks or by using a calibrated rod. Newly bought vessels are... 

However another calibration technique is available when the Calvet type DSC is used. The principle is to apply a known amount of power in a dedicated calibration vessel. To reach this target, a resistance is embedded in the crucible. A known current I is delivered and the corresponding tension U measured, providing the power P = UI that is applied. The corresponding Joule effect provides a DSC exothermic deviation in microvolt (Fig. 2.8). Such an electrical calibration is very interesting as it can apply at any temperature, even at constant temperature. This will be more detailed in paragraph 5 for the calorimetric techniques. 

To understand the direct correlation between the electrical signal and the heat flux, it is needed to consider that a power W is fully dissipated in a calibration vessel surrounded by a fluxmeter composed of crowns of thermocouples (Fig. 2.11). An elementary power Wi is dissipated through each thermocouple producing an elementary variation of temperature ATj between the internal and external weldings (Fig. 2.18) ... 

---