Sack-hole

Fig. 8.6. Sack holes in an 800 im thick glass sheet [351], For the glass composition see Table 1.4.

It is often required to produce not holes or trenches but channels or sack holes respectively depressions, i.e. to etch a desired geometric structure only to a definite depth. This is particularly the case for microfluidic devices containing channels and cavities or for structures used in the bio or medicine technique. 

Various references in the literature describe a process enabling the fabrication of structures, such as deep trenches and sack holes, with various levels of depth in a photostructurable glass using multiple UV-exposure steps [110,144,145, 190,194,195]. A schematic of the process is shown in Fig. 9.31. 

The modified mask method and the protection layer technology enable the simultaneous fabrication of geometrical structures of different depth, such as holes or slits and sack holes or trenches with predefined depths, in a single... 

Determine the cementing operation time and thus the minimum thickening time. Assume a cement mixing rate of 25 sacks/min. Also assume an annular displacement rate no greater than 90 ft/min while the spacer is moving through the open-hole section and a flowrate of 300 gal/min thereafter. A safety factor of 1.0 hr is to be used. 

Thus the number of sacks to give that will be 200 ft in length in the open-hole section is... 

A waste product, whether exempt or not, should always be recycled if economically possible. Oil-based drilling mud typically is purchased back by the vendor for reuse. Unused chemicals are similarly taken back for resale. Arrangements should be made with the mud company for similar arrange for partial drums/sacks of chemical. Muds also may be used on more than one hole. With the advent of closed system drilling, the mud must be moved off location in the event of a producing well. 

Rack, vacuum, 4 ft long, 3 ft high A inch rods 3,4 ft rods, 4, 3 ft rods Receiver, udder type Refractometer, Abbe Ring, cork, 250 mL Rings, cork, 50 mL Sacks, paper, to get dry ice in Stopcock, straight, 2 mm Stopper, rubber, 1 hole. No. 3 Stopper, rubber, 1 hole. No. 7 Strip, terminal, 3 port minimum Support rack, stirring motor rack 10/30 Thermometer, 5 cm immersion, -10 to 150 C Towel to crush dry ice in Transformers, variable Traps, vapor... 

An in-sack dryer is made of a platform that contains holes just large enough to hold jute sacks full of grain. Heated air is blown up through the holes (and grain) via a heater or fan unit. The platform may be constructed from locally available material. A typical oil-fired unit that deals with 2-5 tons of grain is equipped with a fan that delivers 9700 mVh of air heated to 14°C above ambient temperature and consumes about 4.5 L of oil per hour [8]. For 2-ton loading, the moisture removal rate is about 1% per hour. 

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