Transfer applications

G. Y. Eastman and D. M. Ernst, The Heat Pipe, A Unique and Versatile Devicefor Heat Transfer Applications, RCA, Lancaster, Pa., 1966. 

Material Balances Whenever mass-transfer applications involve equipment of specific dimensions, flux equations alone are inadequate to assess results. A material balance or continuity equation must also be used. When the geometiy is simple, macroscopic balances suffice. The following equation is an overall mass balance for such a unit having bulk-flow ports and ports or interfaces through which diffusive flux can occur ... 

In practice, most attention is given to accuracy when the measured variable is the basis for billing, such as in custody transfer applications. However, whenever a measurement device provides data to any type of optimization strategy, accuracy is veiy impoi tant. 

Heat-Transfer Applications Heat-transfer analogs of common mass-transfer terms are ... 

Apparatus for testing materials for heat-transfer applications is shown in Fig. 28-4. Here the sample is at a higher temperature than the bulk solution. 

Aluminum and Alloys Aluminum and its alloys are made in practically all the forms in which metals are produced, including castings. Thermal conductivity of aluminum is 60 percent of that of pure copper, and unalloyed aluminum is used in many heat-transfer applications. Its high electrical conductivity makes aluminum popular in electrical apphcations. Aluminum is one of the most workable of metals, and it is usually joined by inert-gas-shielded arc-welding techniques. 

In heat transfer applications, this jacket is considered a helical coil if certain factors are used for calculating outside film coefficients. The equivalent heat transfer diameter, D, for a rectangular cross-section is equal to 4 w (w being the width of the annular space). Velocities are calculated from the actual cross-section of the flow area, pw (p being die pitch of die spiral baffle), and die effective mass flowrate W dirough die passage. The effective mass flowrate is approximately 60% of die total mass flowrate of die jacket. 

Colburn j-factor = Used in heat-transfer applications. 

Used in mass-transfer applications. Condensation Number... 

Mean radiant temperature The average temperature of the six surfaces of a cubicle enclosure, used in thermal comfort work and in other heat-transfer applications. It is the sum of all the surface areas multiplied by the temperature of the surface divided by the total surface area. 

In some cases, particularly for the radial flow of heat through a thick pipe wall or cylinder, the area for heat transfer is a function of position. Thus the area for transfer applicable to each of the three media could differ and may be A, A2 and A3. Equation 9.3 then becomes ... 

Ax,BEL, D. Heat Transfer Applications in Process Engineering (Noyes, New York, 1984). 

Polarization transfer Application of certain pulse sequences causes the transfer of the greater-equilibrium polarization from protons to a coupled nucleus, e.g., C, which has a smaller magnetogyric ratio. 

The principle of the perfectly-mixed stirred tank has been discussed previously in Sec. 1.2.2, and this provides essential building block for modelling applications. In this section, the concept is applied to tank type reactor systems and stagewise mass transfer applications, such that the resulting model equations often appear in the form of linked sets of first-order difference differential equations. Solution by digital simulation works well for small problems, in which the number of equations are relatively small and where the problem is not compounded by stiffness or by the need for iterative procedures. For these reasons, the dynamic modelling of the continuous distillation columns in this section is intended only as a demonstration of method, rather than as a realistic attempt at solution. For the solution of complex distillation problems, the reader is referred to commercial dynamic simulation packages. 

This section concerns the modelling of countercurrent flow, differential mass transfer applications, for both steady-state and non-steady-state design or simulation purposes. For simplicity, the treatment is restricted to the case of a single solute, transferring between two inert phases, as in the standard treatments of liquid-liquid extraction or gas absorption column design. 

Chapter 3 concerns the dynamic characteristics of stagewise types of equipment, based on the concept of the well-stirred tank. In this, the various types of stirred-tank chemical reactor operation are considered, together with allowance for heat effects, non-ideal flow, control and safety. Also included is the modelling of stagewise mass transfer applications, based on liquid-liquid extraction, gas absorption and distillation. 

The systematic description of heat and mass transfer applications in freeze drying is considered in this section. Mechanistic interpretations are discussed in the fol-... 

Jovin, T. and Arndt-Jovin, D. (1989). FRET microscopy Digital imaging of fluorescence resonance energy transfer. Application in cell biology. In Cell Structure and Function by Microspectrofluorometry (Kohen, E., JG, H. and Ploem, J., eds.). Academic Press, London, pp. 99-117. 

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