Drying defined

Checking the Purification. The purity of the dry re-crystallised material must now be determined, as it is possible that repeated recrystallisation may be necessary to obtain the pure material. The purity is therefore checked by a melting-point determination, and the recrystallisation must be repeated until a sharp melting-point is obtained. Should the compound have no well-defined melting-point e.g.y the salt of an organic acid or base), it must be analysed for one suitable component element, until its analysis agrees closely with that theoretically required. 

In a 250 ml. distilling flask (1) place 122 g. (119 ml.) of p-phenylethyl alcohol and 40 g. of sodium hydroxide peUets (or 56 g. of potassium hydroxide). Heat is evolved. Warm gently until bubbles commence to form and the mixture separates into two sharply-defined layers. Distil slowly water, etc. passes over first accompamed by the gradual dis appearance of the upper phase. FinaUy the styrene passes over at 140 160° (mainly 150°) coUect this separately in a receiver containing about 0 1 g. of hydroquinone. Dry the distillate with a httle anhydrous calcium chloride or magnesium sulphate, and then distil under reduced pressure (2). C oUect the pure styrene at 42-43°/18 mm. The 3rield is 80 g. Add about 0-2 g. of hydroquinone (anti-oxidant) if it is desired to keep the phenylethylene. 

Effective temperature (ET ) is a single number representing those combinations of temperature and humidity which are equivalent in terms of comfort. It is defined as the dry-bulb temperature of the environment at 50% relative humidity. Standard effective temperature loci for normally clothed, sedentary persons are plotted on Eigure 3. The sensation of comfort depends in part upon the wetness of one s skin. Thus, as a person becomes more active the effective temperature lines become more hori2ontal and the influence of relative humidity is more pronounced. 

A continuous pressure filter may be defined as a filter that operates at pressure drops greater than 100 kPa and does not require intermption of its operation to discharge the cake the cake discharge itself, however, does not have to be continuous. There is Htfle or no downtime involved, and the dry soHds rates can sometimes be as high as 1750 kg/m h with continuous pressure filters. 

Basil (Sweet Basil). Basil consists of the brown, dried leaves and tender stems of Ocimum basilicum L. (Labiatae), an aimual native to India, Africa, and Asia, and cultivated in Egypt, southern Erance, Morocco, the Mediteranean countries, and the United States. Basil is one of the oldest known herbs, and it is reported that there are perhaps 50—60 poorly defined Ocimum species which can only be identified according to their chemical components. The flavor of the basihcum type is warm, sweet, somewhat pungent, and pecuhar, ie, methyl chavicol and linalool. It is used with meats, fish, certain cheeses, and tomato-based salads. The fresh leaves are ground and known as pesto with pastas. It is the main component of the Hqueur Chartreuse. 

The time constants characterizing heat transfer in convection or radiation dominated rotary kilns are readily developed using less general heat-transfer models than that presented herein. These time constants define simple scaling laws which can be used to estimate the effects of fill fraction, kiln diameter, moisture, and rotation rate on the temperatures of the soHds. Criteria can also be estabHshed for estimating the relative importance of radiation and convection. In the following analysis, the kiln wall temperature, and the kiln gas temperature, T, are considered constant. Separate analyses are conducted for dry and wet conditions. 

Drying. Drying may be defined as any process that results in the transformation of a fluid-printing ink into a very high viscosity or soHd film. 

Dielectric Constant. Dielectric constant or specific inductive capacity (SIC) is both defined and measured by the ratio of the electric capacity of a condenser having that material as the dielectric to the capacity of the same condenser having air as the dielectric. The dielectric constant of vacuum is unity. Dry air has a constant slightly higher but for most practical purposes it is considered as unity. 

Metallization is defined as the percent of total iron in the DRI which has been converted to metallic iron. For example, DRI having a total iron content of 92% and a metaUic iron content of 85%, has 92.4% metaUization. 

Standards and definitions for whole milk powder, partiy skimmed milk powder, and skimmed milk powder have been set by WHO. This standard apphes exclusively to dried milk products as defined, having a fat content of not mote than 40 mol %. 

The 4,4 -MDA is sold commercially with a diamine assay of 98 —99%. The major impurity is the 2,4 -MDA isomer, which can be present in amounts up to 3%. PMDA products are normally defined by hydrogen equivalent weight and viscosity. Typical products exhibit a 50 hydrogen equivalent weight and a viscosity of 80 140 mPa-s(=cP) at 70°C. PMDA products normally contain, in addition to the isomers and oligomers of MDA, small amounts of aniline, water, chlorides, and various alkylated amines. AH MDA products should be stored in sealed containers in a cool dry area. 

The particle mass retained by each sieve is determined by weighing after drying when necessary, and each fraction is designated by the sieve size it passed and the size on which it was retained. The sieve diameter of a particle is therefore defined as the size of the sieve aperture through which the particle in question just passes through. Mass fractions of the particles are then presented in tabular or graphical form. 

Density. Measurement of density is widely used in the sugar industry to determine the sugar concentration of symps, Hquors, juices, and molasses. The instmment used is called a hydrometer or a spindle. When it is graduated in sucrose concentration (percent sucrose by weight), it is called a Brix hydrometer or a Brix spindle. Brix is defined as the percent of dry substance by hydrometry, using an instmment or table caUbrated in terms of percent sucrose by weight in water solution. Hydrometers are also graduated in °BaumH, stiU in use in some industries. The relationship between °BaumH and density, ing/cm, is °Baumn Baum e = 145(1 — 1/d). 

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