Liquid dynamic compaction

The method of liquid dynamic compaction (LDC) (Chin et al. 1986, Tanigawa et al. 1986) is based on the process of gas atomization (Anand et al. 1980). In gas atomization a stream of molten alloy is broken into a spray of fine particles by a jet of high-velocity gas and the rapidly solidified particles are collected. In LDC, a cooled substrate is placed beneath the atomization core at a distance such that most of the sprayed droplets are partially solidified. The rapidly solidified alloy builds up on the substrate at controllable rates, which can easily exceed 1 cm/min. Rapid solidification is made possible by the supercooling of the high-velocity atomized particles and the good thermal contact with a water-cooled copper substrate. 

The electronic absorption spectra of complex molecules at elevated temperatures in condensed matter are generally very broad and virtually featureless. In contrast, vibrational spectra of complex molecules, even in room-temperature liquids, can display sharp, well-defined peaks, many of which can be assigned to specific vibrational modes. The inverse of the line width sets a time scale for the dynamics associated with a transition. The relatively narrow line widths associated with many vibrational transitions make it possible to use pulse durations with correspondingly narrow bandwidths to extract information. For a vibration with sufficiently large anharmonicity or a sufficiently narrow absorption line, the system behaves as a two-level transition coupled to its environment. In this respect, time domain vibrational spectroscopy of internal molecular modes is more akin to NMR than to electronic spectroscopy. The potential has already been demonstrated, as described in some of the chapters in this book, to perform pulse sequences that are, in many respects, analogous to those used in NMR. Commercial equipment is available that can produce the necessary infrared (IR) pulses for such experiments, and the equipment is rapidly becoming less expensive, more compact, and more reliable. It is possible, even likely, that coherent IR pulse-sequence vibrational spectrometers will... 

All comments above about common and specific variables for ultrasonic baths and probes also apply to continuous US-assisted digestion, which additionally involves dynamic variables. The most influential dynamic variable is the flow-rate of the liquid phase, which should be set in such a way as to avoid compaction of the solid in the chamber and ensure effective contact of the two phases. Consequently, the flow-rate of choice in each case will depend on the particular solid-liquid system. 

CCT, critical cracking thickness Boltzmann constant (1.381x10 local permeability [m ] fracture resistance [N m ] average permeability in/of compact [m ] particle shape factor compact thickness [m] initial particle number concentration [m refractive index of particle material refractive index of dispersion material number density of ion i dimensionless number dimensionless number Stokes number Peclet number capillary pressure [N-m ] dynamic pressure [N m ] local liquid pressure in the compact [N-m local solid pressure in the compact [N-m ] superficial fluid velocity [m-s q gas constant [J K ] centre to centre distance [m]... 

Churaev et al. (1994) recently published actual results on the relationship between wetting film thickness h and disjoining pressure 11, from which the macroscopic contact angle of the liquid on the substrate can be calculated. Today a compact monolayer is known as a French pancake, a bilayer a Swedish pancake and thick films as an American pancake. To sum up, wetting films and their transitions are combined with dynamic processes which elucidate rather complex and yet unsolved issues. 

Compared to natively folded proteins, compact denatured states ( MGs ) experience a modest increase in the number of water molecules in the hydration layer, and a slightly smaller perturbation of hydration water dynamics. Soluble protein-water dynamical coupling has been elucidated by simultaneous examination of transitions in protein and water dynamics as a function of temperature. Hydrated proteins at room temperature exhibit liquid-like motion on the subnanosecond timescale and behave like glasses at low temperature. The dynamical (or glass) transition between the low-temperature glassy state and room-temperature liquid-like state plays an important role in energy flow processes in proteins (see Ref [86] and Chapters 7 and 11). 

---