Being Flexible

The case of vibrational numbering in, say, fluorobenzene illustrates the point that we must be flexible when it may be helpful. Many of fhe vibrations of fluorobenzene sfrongly resemble fhose of benzene. In 1934, before fhe Mulliken recommendations of 1955, E. B. Wilson had devised a numbering scheme for fhe 30 vibrations of benzene. This was so well esfablished by 1955 fhaf ifs use has fended to continue ever since. In fluorobenzene fhere is fhe further complication fhaf, alfhough Mulliken s system provides if wifh ifs own numbering scheme, if is useful very often to use fhe same number for a benzene-like vibration as used for benzene ifself - for which fhere is a choice of Mulliken s or Wilson s numbering Clearly, nof all problems of conventions have been solved, and some are nof really soluble, buf we should all fry to make if clear to any reader jusf whaf choice we have made. 

Textile fibers must be flexible to be useful. The flexural rigidity or stiffness of a fiber is defined as the couple required to bend the fiber to unit curvature (3). The stiffness of an ideal cylindrical rod is proportional to the square of the linear density. Because the linear density is proportional to the square of the diameter, stiffness increases in proportion to the fourth power of the filament diameter. In addition, the shape of the filament cross-section must be considered also. For textile purposes and when flexibiUty is requisite, shear and torsional stresses are relatively minor factors compared to tensile stresses. Techniques for measuring flexural rigidity of fibers have been given in the Hterature (67—73). 

The labyrinth sleeve can be flexibly mounted to permit radial motion for self-ahguiug effects. In practice, a radial clearance of under 0.008 is difficiilt to achieve. 

The labyrinth sleeve ean be flexibly mounted to permit radial motion for self-aligning effeets. In praetiee, a radial elearanee of under 0.008 is diffieult to aehieve, exeept with very small high-preeision maehines. On larger turbines, elearanees of O.Ol5-0.02 are generally used. During maehine eon-struetion, it is important to measure and reeord these elearanees beeause meehanieal seizure or loss in aerodynamie effieieney ean often be traeed to ineorreet labyrinth seal elearanees. 

The four primary coolant pumps are connected to the secondary shield wall by three-link snubbers designed to be flexible under static applied loads (thus, allowing thermal expansion) but become stiff under dynamic loads that might occur during an earthquake. Accordingly, the system is coupled to the wall under seismic loading. 

Oleo-resinous primers plus alkyd finish These are normally used for softwood and should be designed to be flexible and smooth for subsequent paint. 

The simplest wire configuration is a solid conductor with a sheath of insulation that might be flexible PVC or PE. If the wire is rated for 600 volts power frequency AC, the wall thickness would be about 0.020 to 0.030 in. (0.051 to 0.076 cm). The dielectric... 

The literature of science is replete with models. This variety enables one to make some interesting observations. Thus, for example, one rarely regards models as unique or absolute, although, through the choice of a specific one (e.g., a differential equation), unique solutions to problems may be obtained. A model is formulated to serve a specific purpose. Some models may be suitable for generalization, others may not be. These generalizations are more profitably made as extrapolations for scientific purposes, and occasionally as useful philosophical observations. A model must be flexible to absorb new information, and, hence, stochastic processes have broader and richer applicability than deterministic models. 

Therefore, an ideal polymer electrolyte must be flexible (associated with a low Tg), completely amorphous, and must have a high number of cation-coordination sites to assist in the process of salt solvatation and ion pair separation (see Table 11). A review on this subject has been recently published by Inoue [594]. 

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