Portable/removable barriers

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. 

Because these barriers are not anchored into the roadway, they do not require excavation or other related construction for installation. In contrast, they can be assembled and made operational in a short period of time. The primary shortcoming to this type of design is that these barriers may move if they are hit by vehicles. Therefore, it is important to carefully assess the placement and anchoring of these types of barriers to ensure that they can withstand the types of impacts that may be anticipated at that location. Table 9.5 lists the pros and cons of portable/removable barricades. 

Plant instioictions stated that a portable barrier should be put in front of tank trucks being filled, but the barrier was not being used. However, if it had been in use, the driver might have removed it. 

Miniaturized fuel cells are an attractive candidate for next-generation portable power sources. A microfluidic fuel cell is defined as a fuel cell with smaU-scale channels, typically submiUimeter in height, in which reactant delivery/removal and electrochemical energy conversion take place. This type of fuel cell can be incorporated with both metalhc and biological catalysts and normally operates without a physical barrier between anode and cathode compartments. Micromachined fuel cells employing ion-conducting membranes are not covered in this entry. 

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