Facing sand

Modell-sand, m. molding sand facing sand, -stoff, 7n. modeling composition, molding material. 

Specially prepared facing sand is used next to the pattern to give an improved surface to the casting. The mould can then be filled using a backing sand. 

The stacks are moved and again separated into individual panels where they pass a grading station. Those panels requiring touch-up or repair move to the repair stations. Panels then move to the trim saws where edges are trimmed to the final desired size, normally 1220 x 2440 mm (4x8 ft.). Panels are then touch-sanded to final thickness, and pre-finished as desired. Those panels with high quaUty decorative veneer faces are usually filled, stained to the desired tone, and finished with a clear finish. 

Deep Bed Filters. Deep bed filtration is fundamentally different from cake filtration both in principle and appHcation. The filter medium (Fig. 4) is a deep bed with pore size much greater than the particles it is meant to remove. No cake should form on the face of the medium. Particles penetrate into the medium where they separate due to gravity settling, diffusion, and inertial forces attachment to the medium is due to molecular and electrostatic forces. Sand is the most common medium and multimedia filters also use garnet and anthracite. The filtration process is cycHc, ie, when the bed is full of sohds and the pressure drop across the bed is excessive, the flow is intermpted and solids are backwashed from the bed, sometimes aided by air scouring or wash jets. 

High purity 75% ferrosihcon containing low aluminum and calcium can be used in continuously cast heats where nozzle blockage is a problem. In iron melting, this ahoy is desirable to minimize buildup on refractory faces in the furnace or on stopper rods or nozzles. Low aluminum ferroshicons can also help reduce hydrogen pin holes in castings poured in green-sand molds. 

The exposure site is selected according to the service for which the data are to be applicable. For atmospheric service, such factors as marine and industrial contaminants, sunlight, dew and sand abrasion, must be considered. Atmospheric specimens are normally mounted at 45°, facing south. This has been shown to provide about a 2 1 acceleration of failure compared with a vertical exposure. Whether this or other standardised positions are used, the details of the exposure are an important part of the test record. 

Wear protective eyeglasses as a minimum use goggle sand face shield for splash hazards. 

Free dunes have no fixed position, but migrate downwind by erosion on the gently inclined windward side and deposition on the leeward side (slip face) in the same way as described for fixed dunes. The smallest free dunes are common wind ripples that measure only a few centimeters in height. Large dunes are found in extensive dune areas in deserts, in sand seas known as ergs . 

Turbulence may arise either from an increased fluid velocity or from artificial roughening of the forward face of the immersed body. Prandtl roughened the forward face of a sphere by fixing a hoop to it, with the result that the drag was considerably reduced. Further experiments have been carried out in which sand particles have been stuck to the front face, as shown in Figure 3.3. The tendency for separation, and hence the magnitude of the form drag, are also dependent on the shape of the body. 

Figure 3.3. Effect of roughening front face of a sphere (a) 216 mm diameter bail entering water at 298 K (b) As above, except for 100 mm diameter patch of sand on nose...

Apparently a vault had been constructed around the superstructure of the furnace. It was 4.5 x 6 m in cross section and 4 m high. It was constructed of 20-cm-wide flange beams on 0.8 m (front) and 1 m (sides) centers faced on both sides with 10-mm steel plates and filled with dry sand. The explosion displaced the walls about 6 cm. The top of the vault which was supported by a 30-cm beam on top of a 20-cm beam was deflected about 8 cm. Steel doors mounted to slide in angle-iron tracks were blown off. A number of 1.9-cm bolts holding the door tracks were sheared cleanly. The furnace was driven down into the concrete floor and a penetration of some 10 cm was measured. 

Silicates are among the most widely found materials on the face of the earth. They form the basis for much of the soil, sand, and rocks with most of this being of the crystalline variety... 

Initial response may be to put one s head in the sand and deny that anything is wrong, or minimize the effects in one s mind. But eventually as one is forced to face up to one s Immobilization, depression ensues. 

Kaiser Family Foundation (KFF) URL http //www.kff.org E-mail web form Phone (650) 854-9400 2400 Sand Hill Road Menlo Park, CA 94025 A charitable organization that focuses on major health care issues facing the United States, including access to prescription drugs, by doing research and communicating facts, information, and analysis. 

Figure 3. Marshall stability as a function of sulfur and asphalt contents in sand-asphalt-sulfur mixes (15,). Materials used were medium-coarse sand and 150/180 pen. asphalt. All specimens were prepared with 2 hammer blows on one face only.

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