Dispersing crystals

NOTE All-polymer programs employ various types of organic deposit control agents (DCA) such as phosphinocarboxylic acid (PCA) products, which tend to be high temperature-stable sludge dispersants, crystal modifiers, and hardness transporters. 

Another center-fed design that nas only been used on a preparative scale is the vertical spiral conveyor column reported by Schildknecht [Angew. Chem., 73, 612 (1961)]. In this device, aversion of which is shown on Fig. 20-9, the dispersed-crystal phase is formed in the freezing section and conveyed downward in a controlled manner by a rotating spiral with or without a vertical oscillation. 

Excitation of sample by bombardment with electrons, radioactive particles or white X-rays. Dispersive crystal analysers dispersing radiation at angles dependent upon energy (wavelength), detection of radiation with gas ionization or scintillation counters. Non-dispersive semiconductor detectors used in conjunction with multichannel pulse height analysers. Electron beam excitation together with scanning electron microscopes. 

Filter based instruments lack flexibility and are generally employed for the routine analysis of specific elements, whilst instruments utilizing a dispersing crystal have the greatest resolution. There is in principle no limit to this resolution as the detector may be placed at a large distance from the... 

Figure 5. Cold drawing process of a semicrystalline material. The dispersed crystal lamellae (a) under stress are arranged in a tilted stack formation (b).

The precision of replicate analyses was reported to be 10%. The major source of uncertainty was the narrow time frame between saturation of the solution and coalescence of the dispersed crystals to an extent that would alter the nephelometric behavior of the solution. This approach was also nonselective. It was impossible to discriminate against nonanalyte signals arising from crystalline impurities, dust particles, and the like. 

Among wavelength-dispersive spectrometers, a distinction can be made between single-channel instruments and multi-channel spectrometers. In the former type of instrument, a single dispersive crystal/detector combination is used to sequentially measure the X-ray intensity emitted by a sample at a series of wavelengths when this sample is irradiated with the beam from a high power (2—4 kW) X-ray tube. In a multi-channel spectrometer, many crystal/detector sets are used to measure many X-ray Unes/elements simultaneously. 

As displayed in Figures 14.4 to 14.9, k and a behave differently across the main transition region of the amorphous and semicrystalline polymers, Tg and Tm respectively. While Tg is embedded within the transition region, Tm separates melt from the supercooled liquid with its small quantity of dispersed crystals. Figure 14.9 shows k and a versus T dependencies for PA-6 and the two PNCs containing 2 and 5 wt% clay. For... 

Solid body. In amorphous systems, calculate the hole fraction in the vitreous state, h = h P and then the pressure and composition dependencies of the frozen free-volume fraction, FF = FF(P, w). The semicrystalline systems must be treated as supercooled liquids (described by the S-S equation of state) comprising dispersed crystals, described by the Midha-Nanda-Simha-Jain equation of state [see Eqs. (6.32) to (6.34)]. 

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