External arrangement

A similar method is the circulation of the reactor contents through externally arranged tube bundles with help of a circulation pump. It... 

An asterisk is appended to the symbol AS as a reminder that it represents only the configurational entropy computed by considering the external arrangement of the molecules and their segments. Contributions to the entropy resulting from specific interactions between neighbords will be considered later. 

From the ternary feed pure acetone is recovered as overhead fraction. Below the feed point the hquid within the column enriches in 1-butanol and, in turn, splits into two liquid phases. The aqueous phase with very low 1-butanol content is removed in a decanter, which is externally arranged. The organic phase is recycled into the column to recover pure 1-butanol as bottoms. 

The differences consist in the external arrangement of the air circulating fan and product collecting cyclones. 

Explain the difference between macrostates (external arrangements of particles) and microstates (internal arrangements of particles). 

Consider the external arrangement. Since the reactor is adiabatic, it can be represented by the plug-flow model. Referring to Figure 9.10, the conservation equations are ... 

The crystal structure determines not only the arrangement of atoms in the lattice but also the external form of the crystal. 

Wlien an electrical coimection is made between two metal surfaces, a contact potential difference arises from the transfer of electrons from the metal of lower work function to the second metal until their Femii levels line up. The difference in contact potential between the two metals is just equal to the difference in their respective work fiinctions. In the absence of an applied emf, there is electric field between two parallel metal plates arranged as a capacitor. If a potential is applied, the field can be eliminated and at this point tire potential equals the contact potential difference of tlie two metal plates. If one plate of known work fiinction is used as a reference electrode, the work function of the second plate can be detennined by measuring tliis applied potential between the plates [ ]. One can detemiine the zero-electric-field condition between the two parallel plates by measuring directly the tendency for charge to flow through the external circuit. This is called the static capacitor method [59]. 

Interna] and External Seals Mechanical seals are classified broadly as internal or external. Internal seals (Fig. 10-112) are installed with all seal components exposed to the fluid sealed. The advantages of this arrangement are (1) the ability to seal against high pressure, since the hydrostatic force is normally in the same direction as the spring force (2) protection of seal parts from external mechanical damage and (3) reduction in the shaft length required. 

External seals (Fig. 10-115) are installed with all seal components protected from the process fluid. The advantages of this arrangement are that (1) fewer critical materials of construction are required, (2) installation and setting are somewhat simpler because of the exposed position of the parts, and (3) stuffing-box size is not a hmiting factor. Hydraulic balancing is accomphshed by proper proportioning of the seal face and secondary seal diameters. 

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