Letter designation

Viscosity can also be determined from the rising rate of an air bubble through a Hquid. This simple technique is widely used for routine viscosity measurements of Newtonian fluids. A bubble tube viscometer consists of a glass tube of a certain size to which Hquid is added until a small air space remains at the top. The tube is then capped. When it is inverted, the air bubble rises through the Hquid. The rise time in seconds may be taken as a measure of viscosity, or an approximate viscosity in mm /s may be calculated from it. In an older method that is commonly used, the rate of rise is matched to that of a member of a series of standards, eg, with that of the Gardner-Holdt bubble tubes. Unfortunately, this technique employs a nonlinear scale of letter designations and may be difficult to interpret. 

Common names, chemical stmcture, and synonyms for the vitamins are given in Table 3. The names given to the vitamins and/or their letter designations do not foUow a logical pattern and are of historical significance only. Despite this, the nomenclature is in common use. 

Pig. 4. Properties of various latex types. Letters designate dry types numbers indicate latex (158). 

The Tubular Exchanger Manufacturers Assn, has established heat exchanger standards and nomenclature. Every shell-and-tube device has a three-letter designation the letters refer to the specific type of stationary head at the front end, the shell type, and the rear-end head type, respectively (a fully illustrated description can be found in the TEMA standards). Common TEMA designations are listed with specific configurations described below. 

OSHA found multiple defieieneies in the design, management, and implementation of safety and health plans at all the sites that it visited and in all of the plans reviewed. These defieieneies fell into twelve fune-tional areas and were often eommon to all the sites. A diseussion of the findings speeifie to eaeh funetional area follows. Note, for the remainder of this report, that the identities of the sites are masked and are referred to by a randomly assigned letter designation (Site A-K). 

The first letter designates the front end of the heat exchanger, the second letter designates the shell type, or the middle of the heat exchanger, and the third letter designates the back, or the rear, of the heat exchanger. 

Note that in Figure 6-8 and Table 6-2 the letter designations of the stages conform to the latest Standards of the Heal Exchange Institute for Steam fet Vacuum Systems [11]. The letter designates the jet s stage position in the system. 

Figure 7-10 shows durometer scale relationships and hardness ranges. The letter designations refer to the Shore hardness test (Chapter 5, MECHANICAL PROPERTY, Hardness). 

The conformation, i.e. the (approximate) spatial arrangement of the ring atoms of a monosaccharide in the cyclic form, may be indicated by an italic capital letter designating the type of ring shape, and numerals, distinguishing the variants. The... 

Historically, orbital shapes have been identified with letters rather than numbers. These letter designations correspond to the values of / as follows ... 

The angular momentum quantum numbers are often given letter designations, so that when they are stated along with principal quantum numbers, less confusion results. The letter designations of importance in the ground states of atoms are the following ... 

Electrons having the same value of n in an atom are said to be in the same shell. Electrons having the same value of n and the same value of / in an atom are said to be in the same subshell. (Electrons having the same values of n, /, and m in an atom are said to be in the same orbital.) Thus, the first two electrons of magnesium (Table 17-3) are in the first shell and also in the same subshell. The third and fourth electrons are in the same shell and subshell with each other. They are also in the same shell with the next six electrons (all have n = 2) but a different subshell (/ = 0 rather than 1). With the letter designations of Sec. 17.3, the first two electrons of magnesium are in the Is subshell, the next two electrons arc in the 2s subshell, and the next six electrons are in the 2p subshell. The last two electrons occupy the 3s subshell. 

The shell number is represented by 1, 2, 3, and so forth, and the letters designate the subshells. The superscript numbers tell how many electrons occupy each subshell. Thus, in this example, there are two electrons in the Is subshell, two electrons in the 2s subshell, six electrons in the 2p subshell, and only one electron in the 3s subshell. (The 3s subshell can hold a maximum of two electrons, but in this atom this subshell is not filled.) The total number of electrons in the atom can easily be determined by adding the numbers in all the subshells, that is, by adding all the superscripts. For sodium, this sum is 11, equal to the atomic number of sodium. 

Figure 2.14 A possible scheme for the reactions of diiron centres with O2 and substrates. Formal oxidation states, ground spin states and shorthand letter designations are listed below each diiron species. Reprinted from Kurz, 1997, by courtesy of Marcel Dekker, Inc.

For carbon steels with a letter designation in the minimum temperature column of Table IX-1A, the minimum temperature is defined by the applicable curve and Notes in Fig. GR-2.1.2(b)A. If a design minimum metal temperature-thickness combination is on or above the curve, impact testing is not required. 

TABLE 23. Letter designation for naming tertiary amine conformations... 

Figure 12.5 The structures for four tRNA molecules of yeast, (a) Alanyl-tRNA (b) phenylalanyl-tRNA (c) seryl-tRNA (d) tyrosyl-tRNA. The single letter designations identify the sequence of bases along the single chain. Note that several of these are unusual bases, most of which are methylated (Me). Note also the ACC sequence at the 3 terminus of each tRNA. This is the site to which amino acids are attached in the process of protein synthesis, as indicated. These tRNA molecules have a substantial amount of secondary structure created by formation of Watson-Crick base pairs. Finally, note that the anticoding triplet in the bottom loop is shown.

The letter designation originated from spectral lines obtained from the elements. Lines were characterized as sharp, principal, or diffuse (s,p,d). Lines after d were labeled alphabetically starting from the letter f... 

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