Cross braces

The small RING domain coordinates two zinc ions in a cross-brace arrangement [104]. The domain is defined by the presence of eight zinc-binding groups (cysteines and histidines) with a conserved spacing, such that the distance between... 

FIGURE 19-42 A light-harvesting complex, LHCII. The functional unit is an LHC trimer, with 36 chlorophyll and 6 lutein molecules. Shown here is a monomer, viewed in the plane of the membrane, with its three transmembrane a-helical segments, seven chlorophyll a molecules (green), five chlorophyll b molecules (red), and two molecules of the accessory pigment lutein (yellow), which form an internal cross-brace. 

Database searches aimed at identifying related proteins found that the closest structural relative to bacteriocin AS-48 is the effector polypeptide from porcine lymphocytes, NK-lysin.63 Similar to AS-48, this 76-residue protein adopts a globular fold with five helices surrounding a hydrophobic core but lacks a circular backbone.64 Instead, NK-lysin comprises three cross-bracing disulphide bonds that stabilise the structure. Despite the linear backbone of NK-lysin creating differences in the orientation of helix 5 in relation to the one in AS-48, and despite no significant sequence homology between them, the backbone... 

Scaffold risers to be made of 1- by S-in. boards, crosspieces of 2 by 4 in. supports to be properly cross-braced... 

Power wheelchairs began in the 1940s as standard cross-brace folding manual wheelchairs adapted with automobile starter motors and an automobile battery. The cross-braced wheelchair remained the standard for a number of years. When the rigid power wheelchair frame was developed, space became available under the seat for electronic controls, respirators, communication systems, and reclining devices. By the mid-1970s, wheelchairs had evolved to the point where people had acquired a significant level of mobility. 

Depot wheelchairs are intended for institutional use where several people may use the same wheelchair. Generally, these wheelchairs are inappropriate for active people who use wheelchairs for personal mobility. Depot wheelchairs are designed to be inexpensive, accommodate large variations in body size, to be low maintenance, and often to be attendant propelled. They are heavy and their performance is limited. A typical depot wheelchair will have swing away footrests, removable armrests, a single cross-brace frame and solid tires. 

Leg supports may be braced or unbraced. Braced legs are those which are reinforced with either cross-bracing or swaybracing. Sway braces are the diagonal members which transfer the horizontal loads, but unlike cross braces, they operate in tension only. The diagonal members in a sway-braced system are called tie rods, which transfer the load to each adjacent panel. Turnbucldes may be used for adjustments of the tie rods. 

Cross braces, on the other hand, are tension and compression members. Cross braces can be pinned at the center or unpinned, and transfer their loads to the legs via wing plates or can be welded directly to the legs. 

Legs longer than 7 ft should be cross-braced. 

Ch = horizontal. seismic factor, see Procedure 3-3 Cv = vertical seismic factor Ki =end connection coefficient It = moment of inertia, cross brace, in. ... 

This procedure is used for calculating the distribution of vertical and horizontal forces due to wind or seismic loadings for vessels, spheres, elevated tanks, and bins supported on cross-braced legs or columns. 

To design the legs, base plates, cross-bracing, anchor bolts, ring girder, and foundations, it is necessary for the designer to determine the actual distribution of forces. 

Cross-bracing. Cross braces are tension and compression members. They may be pinned at the center or not. If the slenderness ratio of the cross brace exceeds 120, then the cross-bracing must be pinned at the center. 

Check to see if the cross-bracing interferes with piping from bottom head. 

Legs can be either cross-braced or sway-braced. Of the two bracing methods, sway-bracing is the more common. Sway-bracing is for tension-only members. Cross-bracing is used for tension and compression members. When used, cross-bracing is usually pinned at the center to reduce the. sizes of the members in compression. 

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