Particle techniques

Surface Crack Detection Using Magnetic Particle Techniques and Penetrant Inspection Method. 

Suspended Particle Techniques. In these methods of size enlargement, granular soHds are produced direcdy from a Hquid or semiliquid phase by dispersion in a gas to allow solidification through heat and/or mass transfer. The feed Hquid, which may be a solution, gel, paste, emulsion, slurry, or melt, must be pumpable and dispersible. Equipment used includes spray dryers, prilling towers, spouted and fluidized beds, and pneumatic conveying dryers, all of which are amenable to continuous, automated, large-scale operation. Because attrition and fines carryover are common problems with this technique, provision must be made for recovery and recycling. 

Figure 7.6 Effect of injection location on the time history of dispersion when using the virtual particle technique. 1 — rinj = 3.175 cm 2 — 3.01 cm and 3 — 2.84 cm...

Clearly, such real-time, single-particle techniques have great promise in terms of elucidating the chemical nature of different species in tropospheric particles and determining whether they exist as internal or external mixtures. 

The following example is a illustration of how photon and charged particles techniques like the micro-PIXE and micro-Raman spectrometry can be combined to solve an important archaeological issue, namely to unveil the intriguing provenance of the red gemstones mounted on barbarian jewels from the early Middle-Ages [11]. 

When the objective is to prepare an extremely intimate mixture of two or more different oxides, each of them constituted of very small grains or particles, techniques such as spray calcination, oil drop, or freeze drying, the complcxation methods (and generally all methods described in Sections B and C above) and the sol-gel method seem to have the same potential in principle. The... 

In particle-technique methods, no grids are needed. The liquid is considered to be discretized into number of particles with force interacting among individual particles (Heyes et al., 2004). 

Optical techniques are not limited to solid-vacuum interfaces like charged particle techniques, so their further development can expand the range of surface structural studies to solid-solid, solid-liquid, solid-gas and liquid-gas interfaces. 

As seen in Table 4.1, there are many techniques for the study of the chemical composition of the bulk and interfaces. Practically, all these methods can be used to study rocks and soils. A part of these methods, however, demands special instrumentation, for example, nuclear reactors or cyclotrons for studies with neutrons and charged particles. Techniques using electromagnetic or electron radiation can usually be carried out in most chemical, geological, and agricultural laboratories. 

Charge transfer excitations simulated by quasi-particle techniques lack the electron-hole interaction (excitonic effect) because the two excess charges... 

The measurements are conducted for one droplet at a time (single-particle technique) and the technique is fully automated. The existence of multiple particles in the measurement volume (Roisman and Tropea 2001) and... 

We have already met a number of the techniques that have been used to study the structure and reactivity of chemisorbed hydrocarbons. Table 4.1 lists most of the important ones together with a few references that will help the reader to access the wider literature, and to draw attention to the names of the scientists who have made major contributions to their use. It will be appreciated that many of them are only applicable to one class of material, i.e. either to single crystals or to finely divided metal particles techniques that are equally applicable to both classes (e.g. vibrational spectroscopy) are particularly valuable in enabling comparisons between the two classes to be drawn. 

Reaction T/O2 type Particle size, nm Medium pH Cos e-h/ particle Technique Half-life Comments Year Author Refe- rences... 

Coated particle technique has been well employed to synthesize powders for transparent ceramics, especially for YAG. YAG powder retaining the morphology of AI2O3 powder has been synthesized by using a partial wet-chemical process, in order to form yttrium precipitate coated AI2O3 particles [208]. The formation of the so-called core-shell structure had two steps, including (i) direct precipitation of yttrium component at the surface of the AI2O3 particles and (ii) assembly of the yttrium precipitate. A spherical surface reaction process was illustrated. YAG phase... 

Conversely, the modeling approach can be based on the microscopic description working from the smallest scales upward along the general hnes of the program for statistical mechanics. Discrete-particles techniques represent such an approach. 

There exist several other methods, which generalize the dissipative particle technique, such as ... 

Examinations will include liquid penetrant or magnetic particle techniques when surface examination is specified, ultrasonic or radiographic techniques when volumetric examination is specified, and visual inspection techniques will be used to determine surface condition of components and for evidence of leakage. Specific techniques, procedures and equipment, including any special techniques or equipment will be in accordance with the requirements of IWA-22 00 of ASME Section XI and will be defined in the in-service inspection program. 

FIGURE 4.6.3 Comparison of simulation of a pure breakage process by the single particle technique of Ramkrishna et al. (1995) with numerical solution of the discretized form of Eq. (4.5.19). (Reproduced with permission of the American Institute of Chemical Engineers. Copyright 1995 AIChE. All rights reserved.)... 

The breakage process was simulated by Sathyagal et al (1995) using the single particle technique of Section 4.6.4 to obtain the cumulative volume fraction of drops of various sizes x at different times t. Their test of similarity, made through a plot of In t versus In x for 14 different values of the cumulative fraction is represented in Fig. 6.1.1 below. 

Krieger UK, Marcolli C, Reid JP (2012) Exploring the complexity of aerosol particle properties and processes using single particle techniques. Chem Soc Rev 41 6631-6662... 

The question of the velocity profile was also attached directly. A tracer particle technique using treuisparent capillaries... 

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