Visualization principle

Elwing, H. Nilsson, L.-A. Ouchterlony, 0. Visualization principles in thin-layer immunoassays (TIA) on plastic surfaces. Int. Archs. Allergy Appl. Immun., 1976, 51, 757-762. 

The method of volume rendering uses the whole sample volume for visualization. Therefor semitransparent representations of the samples inner structure are possible and the detection of small cracks or faults is much easier compared to the surfaces based techniques (Fig. 4 b). From its principle volume rendering is more time consuming compared to surface representation. 

Detection of this particle accumulation has so far been done visually. To make the particles more easily visible, they have been chemically treated in order to make them light up or flouresce when struck by an ultraviolet light. The operator sits in a darkened room in which the test pieces are illuminated by ultraviolet light. Cracks show up very clearly and in principle this method of inspection is acceptable. Despite the effiency of this method it is well known that a large number of defective pieces pass this test. Why is it so ... 

Therefore we do not need a theory for scattering by pure liquids to be able to deal with solutions experimentally. The theory for scattering by homogeneous liquids is somewhat simpler to visualize than that for solutions, and the same principles are involved for each. Accordingly, we shall develop the results for pure liquids up to a point and then apply the result to solutions by drawing the appropriate analogy. 

Conceptually, the problem of going from the time domain spectra in Figures 3.7(a)-3.9(a) to the frequency domain spectra in Figures 3.7(b)-3.9(b) is straightforward, at least in these cases because we knew the result before we started. Nevertheless, we can still visualize the breaking down of any time domain spectrum, however complex and irregular in appearance, into its component waves, each with its characteristic frequency and amplitude. Although we can visualize it, the process of Fourier transformation which actually carries it out is a mathematically complex operation. The mathematical principles will be discussed only briefly here. 

The emulsification process in principle consists of the break-up of large droplets into smaller ones due to shear forces (10). The simplest form of shear is experienced in lamellar flow, and the droplet break-up may be visualized according to Figure 4. The phenomenon is governed by two forces, ie, the Laplace pressure, which preserves the droplet, and the stress from the velocity gradient, which causes the deformation. The ratio between the two is called the Weber number. We, where Tj is the viscosity of the continuous phase, G the velocity gradient, r the droplet radius, and y the interfacial tension. 

In Section 3.2.3.2, the reader was introduced to dislocations (and to that 1934 paper by Geoffrey Taylor) and an account was also presented of how the sceptical response to these entities was gradually overcome by visual proofs of various kinds. However, by the time, in the late 1950s, that metallurgists and physicists alike had been won over by the principle seeing is believing , another sea-change had already taken place. 

A common principle for the prt)duction of smoke for this purpose is to cvat>-orate a mineral oil by electrically hearing it and to mix the vapor into air. The oil will then condense and form a mist. Different such apparatus can be found on the market. Some of them are aimed for the visualization t f airflow but others are intended lor special effects in theaters, discotheques, etc. Figure 12.3 shows one such apparatus commonly used for this purpose. 

These methods are the simplest, cheapest, and practically most accessible for airflow visualization. They are sold in the form of small glass tubes or plastic bottles through which air is pumped manually. Time for use of one unit is typically one hour or up to one day. One drawback of these two principles is the fact that the emitted smoke is strongly irritating if inhaled and also corrosive. Therefore, they must be used with some care, but this will normally not lead to any major re strictions. Another limitation is the low amount of smoke that is emitted. 

The parameters which characterize the thermodynamic equilibrium of the gel, viz. the swelling degree, swelling pressure, as well as other characteristics of the gel like the elastic modulus, can be substantially changed due to changes in external conditions, i.e., temperature, composition of the solution, pressure and some other factors. The changes in the state of the gel which are visually observed as volume changes can be both continuous and discontinuous [96], In principle, the latter is a transition between the phases of different concentration of the network polymer one of which corresponds to the swollen gel and the other to the collapsed one. 

The modules are computer-based laboratory simulations with engaging activities that emphasize experimental design and visualization of structures and processes at the molecular level. The modules are designed to help students connect chemical principles from lecture with their practical applications in the lab. Every module has a built-in accountability feature that records section completion for use in setting grades and a workbook for students to record and interpret their work. 

Although rings of four carbons and larger are not generally planar (see p. 177), they will be treated as such in this section, since the correct number of isomers can be determined when this is done " and the principles are easier to visualize (see p. 173). 

The principles of stoichiometiy apply equally to solids, liquids, and gases. That is, no matter what phase substances are in, their chemical behavior can be described in molecular terms, and their transformations must be visualized and balanced using molecules and moles. 

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