Striation patterns

Figure 10.5. (a) Polygonal spiral growth hillocks universally observed on 1010 faces of synthetic quartz. (The arrows indicate the summits of the growth hillocks.) (b) Striation patterns commonly seen on the 1010 faces of natural and synthetic quartz grown in NaCl aqueous solution. 

Figure 8. Striation patterns revealed by etching of gallium-doped InSb crystal grown in vertical unstable Bridgman system by Kim et al. (46). (a) Irregular pattern caused by chaotic convection, (b) Regular pattern caused by time-...

Fig. lla and b. Cholesteric liquid crystalline structure of PBLG in m-cresol a, striation patterns observed under a polarizing microscope b, optical diffraction pattern with a beam from the He—Ne gas laser. Concentration is 17% volume fraction of polymer, and cell thickness is 2 mm... 

Figure 2 SEM images of the initial ice spheres and after a reaction with CO2 gas at 193K and SOkPa for 15 and 30 min. (A) surface of a polycry stalline ice sphere before the reaction with clearly visible grain boundaries and striation patterns (B) jackfruit pattern, (C) nucleation sites with clearly visible uneven surface, (D, F) one of the seemingly radially grown pancake", nucleation sites, (E) defect and cracks promote GH crystallization, (G) still well visible porous structure after 30min. reaction, (H) slow blurring of the borders between separate GH crystallites.

Figure 8.1 Formation of laminar striation patterns by intervening plate and...

Until recently, numerical tools and resources were also underdeveloped relative to the magnitude of the striation measurement problem Poincare sections and tracer dispersion simulations were the primary techniques used to characterize mixing. To reconstruct striation patterns successfully by computational methods, it is necessary to track continuous material lines (i.e., dye blobs) injected in chaotic flows. The difficulty of such a numerical experiment is hidden in one word of the previous sentence continuous. The feasibility of tracking material lines or surfaces numerically was explored by Franjione and Ottino, (Franjione and Ottino, 1987). These authors estimations of time and disk space demands... 

Dye structures of passive tracers placed in time-periodic chaotic flows evolve in an iterative fashion an entire structure is mapped into a new structure with persistent large-scale features, but finer and finer scale features are revealed at each period of the flow. After a few periods, strategically placed blobs of passive tracer reveal patterns that serve as templates for subsequent stretching and folding. Repeated action by the flow generates a lamellar structure consisting of stretched and folded striations, with thicknesses s(r), characterized by a probability density function, f(s,t), whose... 

As a result of the crystal growth process Si wafers usually show striations, a variation in the bulk Si resistivity in a concentric ring pattern with a spacing in the order of millimeters. This variation of the bulk Si resistivity modulates the current density and thereby the porosity, which results in an interface roughness [Lel6]. Mesopore formation due to breakdown at the pore tips is very sensitive to striations and can be used for their delineation. 

The number of cross bars, parallel bars, and elements will affect the performance of an SMX static mixer. Singh at al. [62] performed simulations of the two-component flow through an SMX mixer. The number of cross bars and the number of elements were varied, and the results are shown in Fig. 8.35. Contrary to intuition, which would tend toward the most bars to get optimum mixing, the optimum was shown to be six cross bars in the channel. Moreover, after only four elements the number of striations and thus the interfacial surface area was extremely high such that the black and white patterns are becoming difficult to see. 

On crystal faces bounding a polyhedral crystal, step patterns resembling the contour lines on a topographic map or striations in one direction are observable depending on the nature of the face. These show the process of crystal growth or dissolution at an atomic level, and are referred to as the surface morphology or surface microtopography. 

The [hkil] faces, which determine the dog-tooth (scalenohedral) Habitus of calcite crystals, and the prismatic [hkil] face of tourmaline crystals show striations only, never step patterns. These faces are S faces, by PBC analysis, and they appear due to a pile up of steps developing on the neighboring F faces. Yet they develop as large as those that determine the Habitus. 

Crystal faces with curved or wavy surfaces, not exhibiting either striations or step patterns, are rarely encountered. In most cases, these faces appear by dissolution. Rough interfaces grow by the adhesive-type growth mechanism, their normal... 

OkkI. These are minus rhombohedral faces (-R), and in most cases they appear as 0112 faces with nail-head Habitus. Growth step patterns are not observed on these faces, which are characterized by the development of striations parallel to the edges with 1011. ... 

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