Compression ratio, rule

An important reason for the exceptions to the radius ratio predictions is that ions are not hard spheres but somewhat compressible, hence do not have a truly constant radius. Another reason for the inadequacy of the radius ratio rules, particularly when the anions are much larger than the cations, is that some structures are determined by the close packing of the anions, leaving the cations in holes between the anions. In such a case more anions may be packed around a cation of a given fixed radius than are predicted by the radius ratio, so that although the anions are touching each other, they are not touching the cation. However, if... 

One reason for the failure of the radius ratio rules is that ions do not behave like hard spheres. Even those that are hard in the Pearson (1973) sense can still be compressed. This is clearly seen in the way the bond length varies with the bond valence. If cation anion bonds can be compressed, so can the distance between the 0 ions in the first coordination sphere. The stronger the cation anion bonds, therefore, the closer the anions in the first coordination sphere can be pulled together (Shannon el al. 1975). 

Compression Ratio. In order to save on equipment cost, it is desirable to use as few stages of compression as possible. As a rule, the compression ratio is limited by a practical desirability to keep outlet temperatures below 300°F or so to minimize the possibility of ignition of machine lubricants, as well as the effect that power requirement goes up as outlet temperature goes up. Typical compression ratios of reciprocating equipment are ... 

Commutativity simplifications, 450 Compatibility matrix, 73 Compression ratio, 255-256, 258 auditory, 243, 259 Compression rule, 14 Compression threshold, 255-256 Compression, 10 auditory, 243... 

In the early stage of the design of an acid gas injection compressor it is typical to assume equal compression ratios for each stage. This is not a hard rule and adjustments can be made taking into account other considerations. 

Proposal of Ohama s styrene-unsaturated polyester ratio rule (law) in the compressive strength prediction for polyester concrete by using styrene-unsaturated polyester ratio or unsaturated polyester-styrene ratio [36]... 

Fig. 8 Performance comparison between the proposed fuzzy based technique and the crisp rule based technique under vtuying zooming conditions at 4 1 compression ratio a flower, b Stefan...

Fig. 10 Subjective performance of the 20th frame of the akiyo sequence at 4 1 compression ratio using different interpolation techniques a Origintil, b Bicubic, c Lanczos-3, d DCT, e Crisp-rule based Lanczos-3 (Proposed-1), f Fuzzy-rule based Lanczos-3 (Proposed-2)...

A chart which correlates experimental P - V - T data for all gases is included as Figure 2.1 and this is known as the generalised compressibility-factor chart.(1) Use is made of reduced coordinates where the reduced temperature Tr, the reduced pressure Pr, and the reduced volume Vr are defined as the ratio of the actual temperature, pressure, and volume of the gas to the corresponding values of these properties at the critical state. It is found that, at a given value of Tr and Pr, nearly all gases have the same molar volume, compressibility factor, and other thermodynamic properties. This empirical relationship applies to within about 2 per cent for most gases the most important exception to the rule is ammonia. 

As will be outlined below, the computation of compressible flow is significantly more challenging than the corresponding problem for incompressible flow. In order to reduce the computational effort, within a CED model a fluid medium should be treated as incompressible whenever possible. A rule of thumb often found in the literature and used as a criterion for the incompressibility assumption to be valid is based on the Mach number of the flow. The Mach number is defined as the ratio of the local flow velocity and the speed of sound. The rule states that if the Mach number is below 0.3 in the whole flow domain, the flow may be treated as incompressible [84], In practice, this rule has to be supplemented by a few additional criteria [3], Especially for micro flows it is important to consider also the total pressure drop as a criterion for incompressibility. In a long micro channel the Mach number may be well below 0.3, but owing to the small hydraulic diameter of the channel a large pressure drop may be obtained. A pressure drop of a few atmospheres for a gas flow clearly indicates that compressibility effects should be taken into account. 

In general, a material flows poorly if its strength is large relative to the consolidating stress o-j. Jenike called this ratio of o-i to, the flow fimetion (F = ai/f ). It is generally not constant because, as a rule, the compressive strength is not proportional to the principal stress 0-1. This ratio esm be used to make a classification of the flow according... 

---