Factors shapes

The shape of an individual particle is expressed in terms of a shape factor, / This is independent of particle size, and bears connection with the major defining dimension of a 

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Various attempts have been made to allow for particle shapes, through the use of volumes and shape factors. From general considerations it is clear that the volume v of the particles from p grams of solid will be proportional to and the area Ap proportional to... 

Shape anisotropy Shape control Shape factors Shape-memory alloys Shape-selective catalysis Shape selectivity Sharpless catalyst Shaving cream Shaving creams... 

Sphericity. Sphericity, /, is a shape factor defined as the ratio of the surface area of a sphere the volume of which is equal to that of the particle, divided by the actual surface area of the particle. 

Shape. Metal powder particles are produced in a variety of shapes, as shown in Figure 4. The desked shape usually depends to a large extent on the method of fabrication. Shape can be expressed as a deviation from a sphere of identical volume, or as the ratio between length, width, and thickness of a particle, as weU as in terms of some shape factors. 

The two density functions can be related through a simple shape factor as follows. Suppose the mass of a single crystal is and the characteristic dimension of that crystal is E. If the crystal is from a population in which shape is not a function of size, then the mass of any crystal from that population is related to characteristic dimension by a volume shape factor ... 

Population balances and crystallization kinetics may be used to relate process variables to the crystal size distribution produced by the crystallizer. Such balances are coupled to the more familiar balances on mass and energy. It is assumed that the population distribution is a continuous function and that crystal size, surface area, and volume can be described by a characteristic dimension T. Area and volume shape factors are assumed to be constant, which is to say that the morphology of the crystal does not change with size. 

E] Different constants and shape factors reported in other references. Evaluate terms at film temperature or composition. 

Particle shape factor = (surface of sphere)/ Dimensionless Dimensionless Dimensionless... 

FIG. 17-57 Resistance factors for dust layers. Theoretical curves given are based on Eq, (20-78) for a shape factor of 0,5 and a true particle specific gravity of 2,0, [Williams, Hatch, and Greenhurg, Heat, Piping Air, Cond, i2, 259 (1940) Mumford, Markson, and Ravese, Trans, Am, Soc, Mech, Eng, 62, 271 (1940) Capwell, Gas, 15 31 (August 1.93.9)],... 

Drawdown time t = 3.38 h Shape factor = 1.00 Product size ... 

Since the Stokes diameter for the rod-shaped particle will obviously differ from the rod diameter, this difference represents added information concerning particle shape. The ratio or the diameters measured by two different techniques is called a shape factor. 

With four-electrode measurements effected from the surface, an average soil resistivity over a larger area is obtained. The resistivity of a relatively localized layer of earth or pocket of clay can only be accurately measured by using a spike electrode. Figure 3-18 gives dimensions and shape factors, Fg, for various electrodes. 

Since the Wenner rod is mechanically somewhat delicate, it is only used in loose soils or in bore holes. For all measuring rods, the specific soil resistivity is equal to the product of the measured ac resistance and the shape factor Fq, which is determined empirically. 

Also, in cases where the dimensions of a regular particle vary throughout a bed of such particles or are not known, but where the fractional free volume and specific surface can be measured or calculated, the shape factor can be calculated and the equivalent diameter of the regular particle determined from Figure 2. 

One consequence of this is that in a thermoplastic injection moulding the molecular orientations will vary from place to place according to the flow pattern. This may well set up sufficient stresses in the moulding to cause it to distort from its intended shape. Factors affecting the amount of orientation were discussed briefly in the previous chapter and by the author elsewhere. Sometimes the conditions required to minimise distortion may be such that the moulding cycle becomes too long to be economic. In these cases it may be necessary to modify the moulding or at least the position and number of feed... 

Where parameter c is known as the Kozeny constant, which is interpreted as a shape factor that is assigned different values depending on the configuration of the capillary (as a point of reference, c = 0.5 for a circular capillary). S is the specific surface area of the chaimels. For other than circular capillaries, a shape factor is included ... 

The settling velocity of a nonspherical particle is less than that of a spherical one. A good approximation can be made by multiplying the settling velocity, u, of spherical particles by a correction factor, iji, called the sphericity factor. The sphericity, or shape factor is defined as the area of a sphere divided by the area of the nonspherical particle having the same volume ... 

Consider a task analysis for Do-ability. Can the operators do what we have asked them to do Tasks and facilities should be designed with knowledge of ergonomic considerations and performance shaping factors (PSF) so that operator reliability can be designed into the task. 

Human errors may be dependent on the specific accident sequence displayed in the event tree, and, for that reason, may be included in the event tree. This requires the human-factors specialist to consider the context of the error in terms of stress, operator training in response to the accident, di.tgnosiic paiierns, environmental, and other performance-shaping factors. 

Some of the performance-shaping factors (PSFs) affect a whole task or the whole procedure, whereas others affect certain types of errors, regardless of the tasks in which they occur. Still other PSFs have an overriding influence on the probability of all types of error in all conditions. 

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