Plate-like parts

Severe attack frequently occurs at a water-line, which in practice can range from structural steel partly immersed in a natural water to a lacquered tin can used for containing emulsion paint. This can be illustrated by adding increeising amounts of sodium carbonate to a sodium chloride solution in which a steel plate is partly immersed (Fig. 1.48c, d and e). With increase in concentration of the inhibitor, attack decreases and becomes confined to the water-line. The attack at the water-line is intense and is characterised by a triangular pasty mass of corrosion products bounded on the upper surface by a dark-brown membrane that follows the contour of the water-line. The mechanism of water-line attack is not clear, but it is likely that the membrane of corrosion products results in the formation of an occluded cell, in which the anolyte and catholyte are prevented from mixing. These occluded cells are discussed in more detail subsequently. 

This simple relationship between incident and transmitted light is well known as the Boguert-Lambert-Beer law. This expression renders positive values for Ij < Iq. In case of scattering material like TLC plates, a part of the scattered light is emitted as reflectance J from the plate surface to the top. For the hrst approximation of a parallel incident light beam with the intensity /g, some radiation may be scattered inside the layer and some radiation may be absorbed either by the sample or by the layer itself. According to the Schuster equations and with the abbreviation R (the diffuse reflectance of an infinitely thick layer). 

The presence of mica in pearlescent pigments only partly accounts for the appearance of the pigment. A very thin layer of the inorganic oxide titanium dioxide (TiC>2) or iron oxide (Fe2C>3) or both is coated on the mica platelets. The various colors and pearlescent effects are created as light is both refracted and reflected from the titanium dioxide layers. The very thin platelets are highly reflective and transparent. With their plate-like shape, the platelets are easily oriented into parallel layers as the paint medium is applied. Some of the incident light is reflected... 

Until the late nineteen-eighties it was generally accepted that the desirable sputtered films of molybdenum disulphide had the type of structure shown in Figure 10.5. The plate-like or rod-like crystals are oriented with their basal planes perpendicular to the substrate surface, and are superimposed on an amorphous, or perhaps partly micro-crystalline sub-layer. Such films are often referred to as Type I or Type A films, and their production and properties are now well understood. 

Spectrum and/or by its X-ray powder diffraction pattern. These advantageous Altering and drying characteristics are due, in part, at least, to the fact that Form 2 tends to crystallize as more needle-like crystals than the plate-like Form 1 (see Fig. 4.41). 

Like the whole of the Classical Karst of Slovenia, the area investigated lies on the Adriatic sub-plate, a part of the African macroplate. The contact with the European continent lies about 80km to the north. During the last 2 Ma, changes in the motion of the Adriatic sub - plate have led to the establishment of several dextral strike - slip faults of Dinaric trend (i.e. southeast to northwest direction). As a reflection of its 12 km displacement and ongoing neotectonic activity, the Idria Fault is usually considered the... 

While TBAPS was shown to have an inhibition activity comparable to poly(N-vinyl-2-pyrrolidone), known as PVP, the resulting crystal morphology was quite different. PVP and PVCap have been shown to result in plate-like hydrate crystals upon crystallization" ", consistent with part (2) of the proposed mechanism while the hydrate crystals grown in the presence of TBAPS have been observed to be deformed, and particularly elongated, octahedra. 

Hexahydrate, plate-like crystals of pale olive-green color by transmitted light and of a brilliant green to reddish green by reflected light. The crystals polarize light S times as much as tourmaline. Loses its water at 100° and becomes red. Almost insol in water sol in about 1000 parts boiling... 

Lamellae structure Plate-like single crystals that exist in most crystalline polymers. A thin, flat scale or part. 

Talc is an imusually soft mineral that occurs naturally in many parts of the world, but the composition varies considerably from one place to another. Commercial grades have plate-like particles that impart reinforcement to polypropylene at low cost. They have a high surface area and a high aspect ratio that improves the rigidity of plastics. Unlike wollastonite (see later), it is acid-resistant. It is also relatively cheap. 

Parts of the protein form specific three-dimensional structures, for example alpha-helices (spiral like structures) and beta-sheets (plate like structures), which are called the secondary structure. The secondary structure is mainly stabilised by hydrogen bonds. 

---