Stencils

Weighing the loaded car on a coupled-in-motion track scale. An entire train, typically, is hauled at slow speed over the scale. The net weight is determined by subtracting the tare weight stenciled on the car... 

The tare weight (sometimes called stencil weight because it is cut into the cylinder metal) is the total weight of the cylinder and contents, but does not include a removable valve protection cap, if such is used. The saturation gas part of the tare weight is a calculated number which allows for the 11.4 g of acetylene required to saturate each 453.6 g of contained acetone at atmospheric pressure. The correct tare weight is an absolute necessity to the safe charging of acetylene cylinders. 

Image Carriers for Stencil Processes. There are two stencil processes in general use screen printing and stencil dupHcating. Screen printing used for art reproduction is called seriography. 

Manual stencils are made by knife-cutting special film stencil materials. These consist of two plastic layers. The image to be printed is cut through one layer, and this part of the stencil is placed in contact with the underside of the screen. A solvent, which is insoluble in the ink but attaches the cut stencil to the screen, is appHed and then the backing layer is removed. Manual stencils can also be produced by drawing directly on the screens using special materials. 

Photomechanical stencils are of two types direct coatings and transfer films. Direct coatings are either bichromated gelatin or bichromated poly(vinyl alcohol) (PVA). The coated screens are exposed through a positive, washed, and inspected. These screens are used for printing electronic components. They are not practical for commercial work because of the difficulty of reclaiming the screen after use. 

Screenable Resists. Screenable resists or inks (qv) are appHed to the metal-clad substrate through a silk (qv), nylon, or stainless steel screen on which a circuit pattern has been defined. The coating is squeegeed through the stencil onto the substrate, then dried. Depending on whether metal is to be... 

Figure 18.1 A crystal is built up from many billions of small identical units, or unit cells. These unit cells are packed against each other in three dimensions much as identical boxes are packed and stored in a warehouse. The unit cell may contain one or more than one molecule. Although the number of molecules per unit cell is always the same for all the unit cells of a single crystal, it may vary between different crystal forms of the same protein. The diagram shows in two dimensions several identical unit cells, each containing two objects packed against each other. The two objects within each unit cell are related by twofold symmetry to illustrate that each unit cell in a protein cr) stal can contain several molecules that are related by symmetry to each other. (The pattern is adapted from a Japanese stencil of unknown origin from the nineteenth century.)...

Hydrochloric add Floor and furniture polishes Vehicle exhausts Electric stencil cutting machines... 

Sterilant gases Adhesives, glues Cleaning fluids Paint Eelt-tip pens Stencil machines Inks Humidifiers... 

Forty-four commodities stenciled by name on the side in 4-inch-high letters. 

The material of construction has now been stenciled on all tank trucks used for internal transport in the plant where the incident occurred. 

Patrone, /. thimble, shell (for extractions) cartridge pattern stencil mandrel die collet. 

Schablone,/. model, pattern, template mold, form stencil screen. 

The simplest way to identify a specimen is to mark it with letters or numbers applied by stamping with a stencil or number punch. There is, of course, always the danger that the identification marks will be obliterated by corrosion. To guard against this, the several specimens in a test should be identified further by a record of their positions relative to each other or to their supporting device. Before specimens are taken from test their identity should be established in this manner unless inspection has already shown that the identification marks have been preserved. 

Fig. 8. A quasi-chemical view of packing contributions. The dashed curve stencils the fictitious solute of interest, specifying its inner shell (b = 1) exclusion region. To find space in a dense medium, we can consider chemical conversions that extract (right-to-left) solution elements from the space required. 

Other Printing Applications. There are a number of lower volume applications of photopolymer chemistry to the printing industry. Some of these include the production of tactile images (raised Braille patterns) (47) and screen stencil resists... 

Pentagons are facilitated by the help of a stencil made of transparent plastic material, and (Hi) Sample mixture are applied to the narrow portion of the wedge to get the best results. 

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