Hot rolled steel pipe is generally used aboveground for firewater lines. Underground piping systems can be constructed of steel, cement-lined steel, or high-density polyethylene (HDPE). Concrete is sometimes used but is seldom economical except in large diameters. HDPE does not corrode, resists accumulation of scale, and is very ductile and lightweight. But, because it fails when heated, it can only be used in buried installations, where it is also protected from mechanical damage and radiant heat.http://www.wbsteelgroup.com/st....eel-pipe/carbon-stee

In order to improve the properties of silicon sol shell for shell mold casting process, natural plant fibers combined with aluminum silicate fibers at natural-to-aluminum silicate fibers mass ratio of 1:1 were mixed into the slurries preparing for fiber-reinforced shell. The flexural strength of specimens of green shells, fired shells at different temperatures and the self-loaded deformation of the latter at elevated temperature were investigated. http://www.wabonmetal.com/our-....products/shell-mold-

The standard location for blood pressure measurement is the brachial artery. Arm blood pressure monitor that measure pressure at the wrist and fingers have become popular, but it is important to realize that systolic and diastolic pressures vary substantially in different parts of the arterial tree with systolic pressure increasing in more distal arteries, and diastolic pressure decreasing.http://www.vilecohealth.com/bl....ood-pressure-monitor

Concentric butterfly valves are bidirectional. Double offset and triple offset bi-offset butterfly are also bidirectional but with preferred flow (pressure) direction, such as flow from the stem side. Fig. 2.96 shows the preferred flow direction of a flanged end double offset butterfly valve.http://www.sunawevalve.com/but....terfly-valve/bi-offs

It’s often assumed that the difference between hex bolts and screws lies in the tools used to install each – a screwdriver for a screw and a wrench for a bolt. This isn’t always the case, however. Bolts can have heads that we associate with screws and require a screwdriver for installation. Even some screws use nuts, so we’re dealing with gray areas.
http://www.ningbo-bolts.com/bolts/hex-bolts/