Metal number stamped

Figure 2. Schematic of the cross section through a number stamped into metal. Removal of metal down to level (a) results in incomplete obliteration although the number may no longer be readily visible because metal has been smeared into the groove forming the number recovery is easiest in this case. Removal of metal to level (b) leaves behind plastically deformed material this is the situation for which recovery techniques, e.g., etching, can bring out the obliterated numbers. Removal of metal down to level (c) removes all metal plastically deformed during the stamping of the number in this case, recovery is impossible.

If special tools are provided, they shall be packaged in separate, rugged metal boxes and marked special tools for (tag/item number)". Each tool shall be stamped or tagged to indicate its intended use. 

The identification of ammunition is a very complex art. It may be accomplished in any one of a number of methods such as examination of physical size, shape, color markings, stencilled markings, metal stampings, and data written on the packaging material... 

After the patterns on these polymer films are transferred into photoresist films coated on silicon substrates using photolithography, the developed photoresist patterns can serve as a master to make the required PDMS stamps. By combining this method of rapid prototyping with soft lithographic techniques, we can fabricate patterned microstructures of polymers and metals within 24 h of the time that the design is completed. Rapid prototyping makes it possible to produce substantial numbers of simple microstructures rapidly and inexpensively. 

Metallurgical Background. Generally, the obliterated numbers dealt with in the crime laboratory have been produced by stamping, i.e., striking the item with a die with a force sufficient to deform the metal so as to leave behind an impression of the tip of the die. 

Compressed gases are commonly stored in thick-walled metal cylinders designed especially for this purpose. All cylinders must comply with Canadian Transport Commission (CTC) regulations. Containers must be permanently marked with a serial number and specifications for the volume of the cylinder and the maximum pressure it can withstand. Containers must be tested every five to ten years, with the date of the test stamped on the cylinder. 

In the manufacture of percussion caps and detonators the copper blanks are cut from copper strips and stamped to the required shape. The blanks are then plaeed in a gun-metal plate, with the concave side uppermost—a tool composed of a plate of gim-metal, in which are inserted a number of copper points, each of the same length, and so spaced apart as to exactly fit each point into a cap when inverted over a plate containing the blanks. The points are dipped into a vessel containing the cap composition, which has been previously moistened with methylated spirit. It is then removed and placed over the blanks, and a slight blow serves to deposit a small portion of the eap mixture into each cap. A similar tool is then dipped into shellac... 

High-pressure operations should be carried out only with equipment specifically built for this use and only by those trained especially to use this equipment. Reactions should neva- be carried out in, nor heat applied to, an apparatus that is a closed system unless it has been designed and tested to withstand pressure. To ensure that the equipment has been properly designed, each pressure vessel should have stamped on it, or on an attached plate, its maximum allowable working pressure, the allowable temperature at this pressure, and the material of construction. Similarly, the relief pressure and setting data should be stamped on a metal tag attached to installed pressure-relief devices, and the setting mechanisms should be sealed. Relief devices used on pressure regulators do not require these seals or numbers. 

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