Trenches gratings

Some design features of trenches should be noted. Commonly recommended trench dimensional proportions are a width of twice the depth. Under no circumstances should trench depth exceed the width to ensure adequate ventilation. Where heavy wheeled traffic, such as forklift trucks, may occur in a process structure or area with trenches, the trenches can be designed with extra-heavy duty grating that can support heavy equipment. 

Trench covers, per NFPA30, should be used where appreciable quantities of flammable liquids could be caught in the trench system and adjacent equipment could be exposed to direct flame impingement (NFPA 30, NFPA 15). Figure 7-3 shows the details of a wick-type cover where the center third of the grating is open and the other two-thirds are covered by either steel plates or... 

Note Grating type used must have a minimum of 50% open area to prevent flammable concentrations inside the trench and to provide venting. 

Figure 7-3. Drainage Trench with Steel Plate and Grating...

Positive tone resins based on a photoacid generator and either a random copolymer of tetrahydropyranyl methacrylate and methyl methacrylate [137] or random copolymers of tetrahydropyranyl methacrylate, methyl methacrylate, and t-butyl methacrylate (180) were used for fabrication of 3D microchannel structures [264], Simple placed channels connected to cubic or prismatic trenches, which are open to the surface as well as optical grating structures, comprise a set of several parallel channels placed about 10 pm below the surface with connecting reservoirs on both ends. They were fabricated by positive TP microlithography (Fig. 3.75) [264]. 

For good housekeeping, all equipment should be on or above the floor and no pits should be used. On the other hand, grated trenches make it easy to clean the floors, and minimize the number of floor drains. 

Financial support for this work was provided under Air Force Contract No. F33615-98-C-1273. The authors gratefully acknowledge Wright Patterson Air Force Research Lab for FIB-SEM analysis and Case Western Reserve University for trench samples. 

The room must be hquid-tight where the floor meets the walls. Spilled Uquids are to be prevented fium running into adjacent rooms by one of three methods (a) at least a 4-inch (10.16 cm) high sill or ramp at the opening (b) the floors can be recessed at least 4 inches or (c) an open-grated trench can be cut in the floor within the room which drains to a safe location. 

Similarly, silicon thin films are organized as nanoparticle arrays in the direction of the field as shown in Figure 4.26a. Interestingly, the formation of 1-2 p. trenches was also observed in the case of silver films as shown in Figure 4.26b. One can design wave guide or grating or else these silver films can, in principle, be used as a template to form nanowires inside them. 

DNI can proceed in straight linear fashion or in free forms by changing the substrate moving direction with respect to the orientation of the mold grating. Figure 2.8a shows 70 nm trench, 200 nm period gold gratings on PET substrate... 

Figure 2.8 SEM micrographs of (a) 200 nm period, 70 nm trench gold nano gratings (b) continuous 200 nm period gold gratings by DNI...

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