Heated Macrostructures

The hydration of starch evokes thermal effects which are obviously also dependent on the starch variety. This is true because the external temperature does not affect426 the macrostructure and microstructure of starch below 140°C. An estimation of the heat of sorption is useful in determining the concentration of bound water.426-434 The heat of adsorption ranges from 0.255 to 0.100 kJ/mol and depends not only on the variety of starch, but also on the mode of drying of starch prior to measurement (Table XVIII).426... 

The physico-mechanical properties of aminoplasts in the articles are determined by the degree of hardening and macrostructural defects. In the cooling of the articles down to room temperature reactive groups in the polymer are still retained, but their interaction is made difficult due to the loss of mobility caused by the molecules of the reticular polymer because of the latter s vitrification. Simultaneously a nonequilibrium supramolecular structure is recorded. Heat treatment of the articles does not alter the supramolecular structure, the latter remaining invariable. Heat treatment at a temperature below the vitrification temperature may only cause either a certain additional hardening of the binder or increase the... 

There are various secondary processing methods permitting the finished closed-cell foams to be converted to open-cell foams by breaking the cell walls. This is achieved by hydrolysis, oxidation, application of elevated or reduced pressure, heat or mechanical treatment By such a modification an original macrostructure... 

In this volume, the chapters have been divided into four sections. The first serves as an overview of and introduction to the effects of hostile environments on the micro- and macrostructure of polymers. The three chapters included in this section examine heat and radiation effects, and to a lesser extent, shear and solvent effects. 

Macrostructure of ingots as cast is shown on fig. 1. The macrostructure of ingots consisted of equiaxed polyhedral P-grains or grains slightly extended in a direction of heat removal. The cast metal was defect-free. 

Bare grid surface areas on 4BS plates cured at 90 C for 2 h. Water vapour bubbles, formed during heating of the grid, have displaces the 4BS crystals and detached them from the grid surface, (a) macrostructure of the grid/paste interface with a cavern (b) closer view of the cavern with... 

Macrostructure of "plan front" is optimal (dominant) under fast chemical processes ("knowhow") and corresponds to the quasi-plug-flow mode in turbulent flows. This structure of liquid flows mixing provides effective heat- and mass-exchange under not only fast chemical (polymerization, low-molecular products synthesis), but also mass-transfer physical processes (mixing, dispersion, extraction, etc.). 

All the macrostructures mentioned further above, i.e. thin film and screen printed structures, ITO electrodes and paste electrodes can be heated using all the described techniques of AC distortion compensation and also the methods of temperature determination. Till now, macrostructures throughout were subject to permanent heating only, since fast pulsed heating-up is less useful due to the much higher thermal inertia of the electrodes which are carried by isolating supports. 

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