Heads definition

The sinc fiinction describes the best possible case, with often a much stronger frequency dependence of power output delivered at the probe-head. (It should be noted here that other excitation schemes are possible such as adiabatic passage [9] and stochastic excitation [fO] but these are only infrequently applied.) The excitation/recording of the NMR signal is further complicated as the pulse is then fed into the probe circuit which itself has a frequency response. As a result, a broad line will not only experience non-unifonn irradiation but also the intensity detected per spin at different frequency offsets will depend on this probe response, which depends on the quality factor (0. The quality factor is a measure of the sharpness of the resonance of the probe circuit and one definition is the resonance frequency/haltwidth of the resonance response of the circuit (also = a L/R where L is the inductance and R is the probe resistance). Flence, the width of the frequency response decreases as Q increases so that, typically, for a 2 of 100, the haltwidth of the frequency response at 100 MFIz is about 1 MFIz. Flence, direct FT-piilse observation of broad spectral lines becomes impractical with pulse teclmiques for linewidths greater than 200 kFIz. For a great majority of... 

Oxidation, (i) Dissolve 5 g. of potassium dichromate in 20 ml. of dil. H2SO4 in a 100 ml. bolt-head flask. Cool and add 1 ml. of methanol. Fit the flask with a reflux water-condenser and warm gently a vigorous reaction soon occurs and the solution turns green. The characteristic pungent odour of formaldehyde is usually detected at this stage. Continue to heat for 3 minutes and then fit the flask with a knee-tube (Fig. 59, p. 100) and distil off a few ml. Test the distillate with blue litmus-paper to show that it is definitely acid. Then apply Test 3 p. 350) for formic acid. (The reflux-distillation apparatus (Fig. 38, p. 63) can conveniently be used for this test.)... 

PR = perpendicular recording LR = longitudinal recording HFRH = high frequency recording heads RH/HDTV = recording heads for high definition television and Pa = perpendicular perpendicular anisotropy. 

Fig. 3. Definition of the variables used to determine pump head where (-) represents the positions for measurement. See text (eqs. 1—3).

For double suction pumps, using the HI convention, is taken as the total pump flow, although some pubHcations use half-flow, ie, flow per impeller eye. For multistage pumps, the developed head must be taken per stage for the NS calculation. By definition (eq. 9), high head, low flow pumps have low specific speed low head, high flow pumps, such as turbine and propeller pumps, have high specific speed. 

The rest of the rules in Part AD for flat heads, bolted and studded connections, quick-actuating closures, and layered vessels essentially duphcate Division 1. The rules for support skirts are more definitive in Division 2. 

Appendix 4 gives definitions and rules for stress analysis for shells, flat and formed heads, and tube sheets, layered vessels, and nozzles including discontinuity stresses. Of particular importance are Table 4-120.1, Classification of Stresses for Some Typical Cases, and Fig. 4-130.1, Stress Categories and Limits of Stress Intensity. These are veiy useful in that they clarify a number of paragraphs and simphfy stress analysis. 

Functional Definitions Heat-transfer equipment can be designated by type (e.g., fixed tube sheet, outside packed head, etc.) or by... 

The definition of NPSHr may change in the future. A pump is in a definite state of cavitation with the 3% total head loss definition. Many pump users want a more explicit definition of NPSHr, and higher NPSHa safety margins to avoid inadequate NPSHa and cavitation altogether. 

Another distinction in impellers is the way the liquid traverses and leaves the impeller blades. This is called the Specific Speed, Ns. It is another index used by pump designers to describe the geometry of the impeller and to classify impellers according to their clesign type and application. By definition, the Specific Speed, Ns is the revolutions per minute (rpm) at which a geometrically similar impeller would run if it were of such a size as to discharge one gallon per minute at one foot of head. 

Under the heading Alkaloids of Undetermined Constitution, have been included bases about which a good deal of information is available, though they cannot yet be allocated to sturctural groups, either because sufficient, definite information is not available, or because such data are available only about one or two members of an extensive series found in one plant or one genus. The Diehroa bases are probably quinazolines. Of the Erythrophloeum alkaloids some might be placed in the group of... 

Although I have defined terms such as quality control and quality assurance in this chapter, what is important is not the definition but the deeds which it imbues. Whether we call the set of principles I have listed under the heading Quality assurance, Quality Assurance, Quality Improvement or Quality Control makes no difference since it does not change the set of principles. We often seem to invent a term then decide what it means rather than invent or discover a set of principles and think of a suitable name which conveys exactly what we intend without confusing people. Instead of saying Quality control is. .. or TQM is. .. to which there will be many propositions, we should be asking What should we call this group of principles so that we can communicate with each other more efficiently As Shakespeare once said That which we call a rose/By any other name would smell as sweet. ... 

The first commercial buildings, built in about 2000 B.C.E., were simple structures that represented the beginnings of architecture—a scries of columns, walls, and roofs. Columns represented the upright human stance, walls represented human territoriality, and roofs both kept the rain out and created a crown, or head, for the structure. Walls also represented a separation between the plant and animal world and the human world. The walls of a courtyard formed a human space that became the city. Although the form of buildings has evolved over time, buildings today fundamentally provide these same basic human functions artistic expression, separation, definition, and shelter. 

More importantly, this extensive cross-referencing provides information on how the many subjects interrelate. All pertinent information for a subject is included in the definition and/or its cross- referenced component. They are searchable under their own headings based on the reader s needs. In order to cover the needs of different individual interests, many of the subjects have very extensive cross-referencing. Thus, the readers can cross-reference those subjects that meet their needs. This approach simplifies understanding any single subject and, most importantly, shows very vividly the many common similarities and interactions that exist between the subjects in the World of Plastics. 

Most monomers have an asymmetric substitution pattern and the two ends of the double bond are distinct. For mono- and 1,1-disubstituted monomers (Section 4,3.1) it is usual to call the less substituted end "the tail" and the more substituted end "the head". Thus the terminology evolved for two modes of addition head and tail and for the three types of linkages hcad-to-tail, hcad-to-hcad and tail-to-ta.il. For 1,2-di-, tri- and tetrasubstituted monomers definitions of head and tail are necessarily more arbitrary. The term "head" has been used for that end with the most substituents, the largest substituents or the best radical stabilizing substituent (Scheme 4.4). 

I-. - also head r.t rail addition definition 4. If) lail-to-tail linkages in PVAc 324... 

Equation 3.11 is due to Blasius(6) and the others are derived from considerations of velocity profile. In addition to the Moody friction factor / = 8R/pu2, the Fanning or Darcy friction factor / = 2R/pu2 is often used. It is extremely important therefore to be clear about the exact definition of the friction factor when using this term in calculating head losses due to friction. 

Upon receipt at the analytical laboratory, the receiving department should immediately examine the integrity of the samples. If a sample is damaged, or its integrity is in any way questionable, or it does not meet the protocol definition (e.g., leaf rather than head lettuce), then a re-shop should be ordered (i.e., the shopper is required... 

This equation defines the flow coefficient, Cv. Here, SG is the fluid specific gravity (relative to water), pw is the density of water, and hv is the head loss across the valve. The last form of Eq. (10-29) applies only for units of Q in gpm and hv in ft. Although Eq. (10-29) is similar to the flow equation for flow meters, the flow coefficient Cv is not dimensionless, as are the flow meter discharge coefficient and the loss coefficient (Af), but has dimensions of [L3][L/M]1/2. The value of Cv is thus different for each valve and also varies with the valve opening (or stem travel) for a given valve. Values for the valve Cv are determined by the manufacturer from measurements on each valve type. Because they are not dimensionless, the values will depend upon the specific units used for the quantities in Eq. (10-29). More specifically, the normal engineering (inconsistent) units of Cv are gpm/ (psi)1/2. [If the fluid density were included in Eq. (10-29) instead of SG, the dimensions of Cv would be L2, which follows from the inclusion of the effective valve flow area in the definition of Cv]. The reference fluid for the density is water for liquids and air for gases. 

---