Patterned ground

Figure 10 Deep clastic dike in a coal of the Weller Coal Measures of the Allan Hills, Antarctica, interpreted as infill of periglacial polygonal patterned ground (E. S. Krull and hammer for scale).

Daily B. and Cooper M. R. (1976) Clastic wedges and patterned ground in the Late Ordovician-Early Silurian tilUtes of South Africa. Sedimentology 23, 271-283. 

Mabbutt, J.A. (1979) Pavements and patterned ground in the Australian stony deserts. Stuttgarter Geographische Studien 93, 107-123. 

Washburn, A.L. (1969) Desert varnish. In Washburn, A.L. (Ed.) Weathering, Frost Action and Patterned Ground in the Mesters District, Northeast Greenland. Copenhagen Reitzels, pp. 14—15. 

Washburn, A.L. 1956 Classification of patterned ground and review of suggested origins. Bull. Geol. Soc. Amer., 67,327 02... 

Diflfiisive processes nonnally operate in chemical systems so as to disperse concentration gradients. In a paper in 1952, the mathematician Alan Turing produced a remarkable prediction [37] that if selective diffiision were coupled with chemical feedback, the opposite situation may arise, with a spontaneous development of sustained spatial distributions of species concentrations from initially unifonn systems. Turmg s paper was set in the context of the development of fonn (morphogenesis) in embryos, and has been adopted in some studies of animal coat markings. With the subsequent theoretical work at Brussels [1], it became clear that oscillatory chemical systems should provide a fertile ground for the search for experimental examples of these Turing patterns. 

Unlike the aircraft turbiae, the ground-based gas turbiae operates continuously at the same power setting, usually 60—80% of maximum power output except when starting. Air and fuel flow patterns are constant and the combustor can be tuned to minimise smoke formation and high metal temperatures. 

Rotary atomisation produces an excellent surface finish. The spray has low velocity, which allows the electrostatic forces attracting the paint particles to the ground workpiece to dominate, and results in transfer efficiencies of 85—99%. The pattern is very large and partially controlled and dkected by shaping ak jets. The spray when using a metallic cup has relatively poor penetration into recessed areas. Excessive material deposited on the edges of the workpiece can also be a problem. 

The detailed analysis of the way in which the overall and internal structure of PCNTs apparently arise is discussed elsewhere[20j. Here, we draw attention to some particularly interesting and unusual structures which occur in the body of the nanotubes. An expansion of the section of the central core which lies ca. 5 below the tip of the nanotube in Fig. 1 is shown in Fig. 2. Loop structures occur at points a-d and a -d in the walls in directly opposing pairs. This parallel behaviour must, on the basis of statistical arguments, be related and we interpret the patterns as evidence for a hemi-toroidal connection between the inner and outer adjacent concentric graphene tubes (i.e., turnovers similar to a rolled-over sock). That the loops, seen in the HRTEM, are evidence for very narrow single-walled closed-ended tubes trapped within the walls can be discounted, also on statistical grounds. 

Guy line loading (assume ground anchor pattern consistent with manufacturer s guying diagram shown on the nameplate). 

This recommendation is applicable for most conditions encountered in the use of this type mast. There will be exceptions where location clearance, ground conditions, or other unusual circumstances require special considerations. Figure 4-5 shows a recommended guying pattern that may be used under general conditions in the absence of an authorized API manufacturer s recommendations. Guy lines should be maintained in good condition, free from rust, corrosion, frays, and kinks. Old sand line is not recommended for guy lines. 

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