Wedge barriers

Wedge barriers have a quick response time (normally 3.5-10.5 seconds, but can be 1-3 seconds in emergency situations. Because emergency activation of the barrier causes more wear and tear on the system than does normal activation, it is recommended for use only in true emergency situations. Regular maintenance is needed to keep wedge fully operational. 

All three wedge barrier designs have a high crash rating, thereby allowing them to be employed for higher-security applications. ... 

In contrast to wedge barriers and crash beams, which are typically installed separately from a fence line, gates are often integrated units of a perimeter fence or wall around a facility. Gates are basically movable pieces of fencing that can be opened and... 

No excavation is required in the roadway itself to install crash beams. All three crash beam designs possess a low crash rating relative to other types of barriers, such as wedge barriers, and thus they typically are used for lower-security applications. 

Portable/removable barriers, which can include removable crash beams and wedge barriers, are mobile obstacles that can be moved in and out of position on a roadway. For example, a crash beam may be completely removed and stored off-site when it is not needed. An additional example would be wedge barriers that are equipped with wheels that can be removed after the barricade is towed into place. 

Wedge barriers equipped with wheels can be easily towed into place. ... 

Multiple-Hea.rth Roasters. The circular types consist of a series of hearths arranged vertically in such a way that the ore entering the top is rabbled and dropped down from hearth to hearth, until it is completely oxidized. The hearths are usually stationary and the plows revolve, such as in the Wedge, Herreshoff, Ord, Skinner, and other roasters (21). In other furnaces, the hearths revolve and the rabbles are fixed, eg, the deSpirlet and its modification, the Barrier. 

A device consisting of an array of frustum-shaped cells that contain a drug dispersed in a permeable matrix is shown to obey zero-order release kinetics following an initial burst phase. Geometric shapes of dissolving solids or diffusion systems and the constraints of impermeable barriers influence mass transport and can be exploited as in the constant release wedge- or hemispheric-shaped devices. 

It is importcuit, from a practical point of view, that extremely thin black films are ruptured under the condition of reduced humidity, since evaporation of the dispersion medium leads to their ultimate thinning and appearance of high de- wedging pressures. Here are two possibilities to produce stable (under the conditions of dry air) foams. On the one hand, this is reduction of permeability of adsorption layers for water vapours and thus inhibition of the evaporation rate. On the other hand, it is the use of surfactants for foam stabilisation leading to the formation of a structure-mechanical barrier, i.e. gel-like interlayer. 

The Lower Series was deposited on a flooded erosion surface over a Paleozoic substrate, a marine surface on which were developed vast lagoons, volcanic flows, tidal flats and barriers. Truely marine conditions prevailed only over the northern part of the region. The sandstones of the Lower Series are not as uniformly continuous as those of the Tj and T. They are generally lenticular or sometimes form wedges interrupted by the volcanic rocks. A great potential for the accumulation of hydrocarbons in lithostratigraphic traps may develop under these conditions like in the sandstones in the upper part of the Lower Series in TKT-i, BKZ-i and BKZ-2. 

---