Propeller blades

Scaled Composites used an all graphite construction for a two blade controllable pitch unit for the Raptor unmanned aerial vehicle, which could be converted to a manned configuration. 

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Figure S.7 The subunit structure of the neuraminidase headpiece (residues 84-469) from influenza virus is built up from six similar, consecutive motifs of four up-and-down antiparallel fi strands (Figure 5.6). Each such motif has been called a propeller blade and the whole subunit stmcture a six-blade propeller. The motifs are connected by loop regions from p strand 4 in one motif to p strand 1 in the next motif. The schematic diagram (a) is viewed down an approximate sixfold axis that relates the centers of the motifs. Four such six-blade propeller subunits are present in each complete neuraminidase molecule (see Figure 5.8). In the topological diagram (b) the yellow loop that connects the N-terminal P strand to the first P strand of motif 1 is not to scale. In the folded structure it is about the same length as the other loops that connect the motifs. (Adapted from J. Varghese et al.. Nature 303 35-40, 1983.)...

Figure 13.15 Schematic diagram of the heterotrimeric Gap complex based on the crystal structure of the transducin molecule. The a suhunit is hlue with some of the a helices and (5 strands outlined. The switch regions of the catalytic domain of Gq are violet. The (5 suhunit is light red and the seven WD repeats are represented as seven orange propeller blades. The 7 subunit is yellow. The switch regions of Gq interact with the p subunit, thereby locking them into an inactive conformation that binds GDP but not GTP.

Axial or propeller blade fatis are eithet Irelt or gear driven. Some drivers are variable speed tnoiors. and some fatis have variable pitch blades. Iti s iecial circumstances, steam turbine, gas or gasolitie etigine drivers are used. Geais should be carefully specilied to avoid overload and should be special ) sealed to prevent moisture entering the case. 

The cathodically protected primary structures may be the hulls of ships, jetties, pipes, etc. immersed in water, or pipes, cables, tanks, etc. buried in the soil. The nearby unprotected secondary structures subjected to interaction may be the hulls of adjacent ships, unbonded parts of a ship s hull such as the propeller blades, or pipes and cables laid close to the primary structure or to the cathodic-protection anode system or groundbed. 

The evolution of nitrogen aids in removing dissolved air. A salt bridge (4 mm tube) attached to the saturated calomel electrode is filled with 3 per cent agar gel saturated with potassium chloride and its tip is placed within 1 mm of the mercury cathode when the mercury is not being stirred this ensures that the tip trails in the mercury surface when the latter is stirred. It is essential that the mercury-solution interface (not merely the solution) be vigorously stirred, and for this purpose the propeller blades of the glass stirrer are partially immersed in the mercury. 

For the past few decades, manufacturers have been streamlining components and installing onboard computers to hit the propeller blades for maximum efficiency for the wind conditions. In the 1980s, the average turbine was 20 meters high with a 26-kilowatt (kW) generator and a rotor diameter of 10.5 meters. A typical turbine today can be 55 meters high, with a rotor diameter of 50 meters and a capacity of 1.6-MW. The power it produces may supply 500 homes. 

The crowded conditions inside a reactor due to the presence of various probes and a phial-breaker usually limit the number and size of propeller blades which can be accommodated. However, these fittings also break up the laminar flow (which is inimical to efficient mixing) so that turbulence can be achieved at stirring speeds well below that which would be required for a cylindrical reactor free of solid obstructions. If there is sufficient space, mixing can be improved considerably by having two propeller blades, ca. 1.5 cm apart, on the same shaft, with opposite chiralities, so that the layer of fluid between them is subjected to an exceptional shear-rate. 

The operator should be protected by means of a safety shield. A glass (propeller-blade) stirrer passing through the open neck of the Erlenmeyer flask is convenient rapid stirring is not essential. 

Axial flow is flow developed by axial thrust of a propeller blade, practically limited to heads under 50 ft or so. 

Cavitation as phenomenon recognized and investigated on propeller blades... 

Conventional stirred-tank polymeric reactors normally use turbine, propeller, blade, or anchor stirrers. Power consumption for a power-law fluid in such reactors can be expressed in a dimensionless form, Ne = Reynolds number based on the consistency coefficient for the power-law fluid. Various forms for the function f(m) in terms of the power-law index have been proposed. Unlike that for Newtonian fluid, the shear rate in the case of power-law fluid depends on the ratio dT/dt and the stirrer speed N. For anchor stirrers, the functionality g developed by Beckner and Smith (1962) is recommended. For aerated non-Newtonian fluids, the study of Hocker and Langer (1962) for turbine stirrers is recommended. For viscoelastic fluids, the works of Reher (1969) and Schummer (1970) should be useful. The mixing time for power-law fluids can also be correlated by the dimensionless relation NO = /(Reeff = Ndfpjpti ) (Tebel et aL 1986). 

Fig. 8. Structures of Sema3A-65K and Sema4D. (A) The structure of Sema3A-65K viewed from the top face of the molecule. The molecular surface (semi-transparent) is also indicated. The individual Sema3A-65K pseudo-repeats corresponding to the individual j3 propeller blades are colored (from -N to -C terminus) in red (1), orange (2), yellow (3), green (4), cyan (5), blue (6) and magenta (7). (B) The structure of Sema4D homodimer. The sema domain is in red, the PSI - in green, and the Ig - in blue. (See Color Insert.)...

Figure 2. Domain organisation, three-dimensional structure and sequence-into-colour translation of human coronin-lC. Top, True to scale schematic of the domain structure of human coronin-lC N, N-terminal coronin-specific signature, PI-7, p-propeller blades, C, unique C-terminal region, CC, coiled coll. Middle, top and side view of the structural homology model of human coronin-1 C, based on the crystal structure of human coronin-IA. p-propeller blades 1 and 2 that represent an unconventional and a typical p-propeller blade, respectively, are oriented to the bottom (left) and to the front (right). See also Chapter 5 by Bernadette McArdle and Andreas Hofmann. Figure 2 legend continued on the next page.

This common fold variously contains from four to nine anti-parallel four-stranded beta sheets. These are arrayed radially with a geometry similar to a ship s propeller, each propeller blade being composed of four anti-parallel strands, each slighdy twisted in the same orientation. The height or... 

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