1) A corrosive electrolytic action that weakened this bolt, resulted in the failure of a clamp joining two high pressure pipes.
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2) A stone recoved from a passenger vehicle interior shows tire rubber deposits from a heavy construction vehicle twin tire wheel and windshield glass fragments.
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3) A few drops of moisture caused a portion of the glass envelope to explode, exposing the filament to the atmosphere that burnt out the light. See P-G #18
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4) A soda-lime bottle glass shard recoverd from a foodstuff.
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5) A macro photo in polarized light confirmation of proper heat treatment for the tempering of glass in a disputed failure.
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6) Poly Ethylene Terephthalate (PET) shard recovered from foodstuff. see IG #23
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7) Numerous pin holes in copper piping pre-dated a building fire.
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8) A sidewall defect as seen from the inside of the tire.
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9) A defect in the coating of the heater element corroded to the point at which the current carrying portion of the element was exposed to the hot tub water.The heater unit, fortunately, exploded when no one was near.
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10) Asbestos - Individual fibers from bundles recovered from vermiculite home insulation (see PG #19) are birefringent when viewed with polarized light, as are tremolite asbestos, the usual material found in this type of insulation.
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11) Cotton swabs from a pharmacy when viewed at 40 power magnification with plain light on the left and through crossed polars on the right, are seen to be a fiber blend. The twisted rope like strands are natural cotton while the smooth straight fibers are manufactured.
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12) Deflagrations and Detonations - The on-line Gas Explosion Handbook is an excellent reference for those who investigate fires and explosions. The subsonic deflagrations and supersonic detonations are well illustrated and discussed. The top photo is the result of the ignition and deflagration explosion of a solvent spill, vapor cloud. The bottom two photos are the back side of a steel fire door after a lean, gaseous hydrocarbon cloud ignited, then detonated. The high impulse impact of the blast originating in the storey below the fire safety door, pushed the steel door upward with sufficient velocity to 'pop' both hinge pins out of the door mounts and project them a yard away from the rear side of the door frame.
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13) Dog Hair - An assortment of dog hair fragments display the seqmented outer sheath and hollow core visible on some strands.
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14) Burlap or Jute - The two photos are shown with plain light on the left and through phase contrast image enhancement on the right.
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15) Glass Fibers - The numbered fractured ends in the center of the field of view are characteristic for the straight, smooth, uniform, 'fiberglass' glass fibers.
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16) Pink Home Insulation - The material is composed mainly of glass that has been melted and 'spun' like candyfloss. The end result is a collection of randomly oriented, un-even fibers, 5 to 10 microns in diameter.
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17) Mineral Wool Insulation - This material is a mixture of metal furnace slag and basaltic rock. The minerals from which the wool is manufactured have a much higher melting point than does the glass based materials. For some applications the more dense, more brittle and higher temperature tolerance of the mineral insulation is a better but more expensive choice.
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18) The filament from PG #3 was 'on' at the time of the glass envelope destruction.
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19) Vermiculites used as attic insulations, packaging filler or soil amendments may contain an asbestos contaminent that can be separated from some of the lighter portions of the material, by water flotation. Collection, drying and examination of the fraction that sinks may reveal the presence of the mineral fiber bundles shown.
The individual fibers from these bundles are seen in PG #10.
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20) Contamination from paint application 'overspray' may take several formats depending upon paint chemistry, colour, application methodology, atmospheric conditions, distances and other parameters. Consideration of the above requirements indicated that virtually perfect, white spheres, should have been the end result of true overspray contamination that was confirmed by the particles shown. Other 'white spotting' was found not to be due to paint overspray.
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21) 'Run Off' - The foreground barren soil has a salt content ten times higher than that in which the crop is flourishing.
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22) Tree Sap - Hot molten tree sap dissolved the clear coat and ate into the pigment layer of the vehicle parked beneath trees.
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23) Volcanic Ash - The ash was recovered from the top surface of vehicles in southern British Columbia days after the eruption of Mt. St. Helens in 1980. The images are at 40x magnification with polarized light illumination on the left and plain light on the right.
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24) Sheep wool displays the characteristics common to all hairs, that of a segmented outer surface with the hollow central core.
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25) Zinc Coating Failure - Spot welding of galvanized sheet metal requires some repair work after the joint has been made. Zinc is a relatively low temperature melting element and the heat required to bond the steel sheeting destroys the local integrity of the protective coating.
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26) Zinc Coating Defects - New threaded rod was stored in a very damp location for a long time and defects in the coating have become evident. A perfect coating is difficult to create.
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