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Barium, typically as barium nitrate imparts a yellow or "apple" green color to fireworks; [30] for brilliant green barium chloride is used. Barium peroxide is a catalyst in the aluminothermic reaction for welding rail tracks. It is also a green flare in tracer ammunition and a bleaching agent. [31] Barium titanate is a promising electroceramic ...
Contour stamp A toy rubber stamp featuring a pterosaur Fabrication of stamp by photopolymer method Ink pad "Barock Made in East Germany" (c.1960), in the collection of the Museum Europäischer Kulturen. Materials besides rubber can produce a stamp. Woodcut and linocut, the carving of linoleum, are art forms based on the same principles ...
The following types of material are excluded (although they may also be collected by chemical stamp enthusiasts): Postal stationery, [14] e.g. a postcard depicting a chemist with a non-chemical stamp affixed; Cinderella, local, private or personal issues, i.e. unofficial stamps; Non-postal stamps, e.g. revenue stamps [15]
A composite, thin PDMS stamp with a rigid back support has been used for patterning to help solve this problem. Magnetic field assisted micro contact printing: to apply a homogeneous pressure during the printing step, a magnetic force is used. For that, the stamp is sensitive to a magnetic field by injecting iron powder into a second layer of PDMS.
Barium chromate – used in delay compositions, e.g. in fireworks rockets; Lead chromate – used in delay compositions; Potassium dichromate – used infrequently as an oxidizer; can be used as a surface treatment for passivation of magnesium particles, also as a catalyst and in some matches; potassium perchlorate often added; Oxides and ...
The following types of material are excluded (although they may also be collected by crystallography stamp enthusiasts): Postal stationery, [10] e.g. a postcard depicting a crystallographer with a non-crystallographic stamp affixed; Cinderella, local, private or personal issues, i.e. unofficial stamps; Non-postal stamps, e.g. revenue stamps [11]
An 8¢ air mail stamp issued in 1963 was the first stamp printed for trials with new cancelling machines. [8] The 5¢ City Delivery issue of 1963 was the first commemorative issue produced with tagging. [9] Precancelled stamps and service-inscribed stamps are not usually tagged because they need not be routed through the cancelling equipment.
Barium ferrite is a common material for speaker magnets. The materials can be formed into almost any shape and size using a process called sintering, whereby powdered barium ferrite is pressed into a mold, and then heated until it fuses together. The barium ferrite turns into a solid block while still retaining its magnetic properties.