Bum marks

Analysis Methods. Until a few years ago probably no more than 2000 analyses of ancient and medieval coins had ever been performed— and then only on more common coins. The reason was simply that analysis of these artifacts required chemical methods which destroyed at least a portion of the coin. Even the less harmful method, spark spectroscopy, is not permitted by the major museums since it leaves a visible bum mark on the edge of the coin and requires temporary transfer of the coin from the museum to a laboratory. 

In principle, bearing destruction is caused by arcing on their surfaces. Because of the very small contact surfaces, current density is extremely high. Chatter marks and bum marks form. The surface becomes scratched, and mechanical abrasion accelerates,... 

F (93.3°C) is a limitation of the application of the regulations and should not be construed as indicating that liquids with higher flash points will not bum. Markings such as NONFLAMMABLE or NONCOMBUSTIBLE should... 

His eye focused on a two-centimetre bum mark scoring the composite wall. Instinct or a well-written extended sensory analysis program, it was the result which mattered. That bum mark was on the cover of a net conduit inspection panel, and it was fresh. When he switched to infrared it still glowed a faint pink. With the spectmm active, other bums became apparent, a small ruddy constellation sprayed around the corridor walls, every glimmer corresponding to an inspection panel. 

The bum mark on Stanyon s chest healed over. Clothes sprang up to conceal his body. "We d better get along to the SD control centre and kick some butt," he said. 

Air pressure inside a mold can induce bum marks and corrosion after Imig-term use for coti-ventional injection molding. For microinjection molding, high injection velocity and complex geometry of microfeatures may cOTitribute to air entrapment and could eventually lead to... 

Fig. 9. An initially aligned sample of rigid rod microtubule biopolymers in solution after it has been hit by radiation. The sample is viewed between crossed polarizers. The burn mark is centrally placed. The alternating dark and light bands are domains that have a different orientation. The transition from uniform alignment to domains with different orientation takes place in seconds after the sample is irradiated. The burn mark has dimensions of roughly 0.5 x 3 mm. The shift of the domains with respect to each other is approximately 0.5 mm as witnessed by the distortions of the bum mark.

H. Bum marks. Burning from transformer failures or conductor faults could damage the pole so that it cannot withstand changes in mechanical stress. 

Bum marks Black or brown burnt areas on the part located at furthest Air entrapment in mold due to lack of venting... 

Bum injuries may be associated with shock and can be seen as bum marks on the body at the points of current entry and exit or may also occur in the burning of internal tissue. However, severe burn injuries are more likely to arise as a consequence of short circuit flashover. In fact the number of fatalities arising from this latter cause is similar to that resulting directly from electric shock. 

Air Vent n A passageway, typically a fine groove or scratch, between a mold cavity and the outside edge of the mold face, that allows air to escape as melt is injected into the cavity. See Bum Mark. 

Bum marks Incorrect filling pattern Relocate gate Improve venting... 

The diesel efifect is a pure venting problem. It can occur near blind holes, fillets, the end of flow paths and near points where several flow fronts fuse. It happens whenever the air cannot escape or not quick enough via commissures, venting channels or ejector fits. Towards the end of the injection process, the air is compressed and thus heated to a high degree. The result is very high temperatures which can cause bum marks on the plastic as shown in Figures 9.20 and 9.21. 

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