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Glass (Forensics)

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chichi's version from 2016-10-24 15:09

Section 1

Question Answer
glassinorganic production of fusion that has been cooled to a rigid condition without crystallization
flat glassarchitecture and automobiles
containersbottles, glasses, and jars
glass fibersinsulation
tempered glassside and rear automobile windows
Does not shatter but fragmentstempered glass
laminated glassautomobiles windshields
layer of plastic film between two layers of glasslaminated glass
soda limecontainers and windows
leaded glasshouseware and decorations
borosoliacteindustry, lamps, cookware
specialoptical, electronics
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Section 2

Question Answer
soda-limewindow and bottle glass
soda (sodium carbonate)lowers melting point
lime (calcium oxide)prevents dissolution in water
borosilicatesheat resistant glass and headlights (boron oxide)
fluxesadded to formers to lower melting temperature and reduce cost of production
stabilizers add chemical resistance
decolourantsclarify glass
forming agentssolidify quickly after cooling without crystallizing
refining agentsremoves bubbles during refining process
memorize

Section 3

Question Answer
Formingchanges in viscosity
annealing and coolingsolidifies without crystallization
secondary processingtempering, coating, coloring, decoloring
temperingadditional strength; safer breakage pattern; heated to 700C and quickly cooled with compressed air
coatingdecoration; protection; and strengthening of glass
decoloringselenium and cobalt counterbalances yellow or green of iron
irongreen, brown, blue
manganesepurple
cobaltblue, green, pink
titaniumpurple, brown
ceriumyellow
goldred
class characteristicsdensity; RI; color; elemental components
individual characteristicsfracture matching
density determinationsink-float method; glass supsension point
density with toxic liquidsbromobenzene and bromoform
Need at least ___ of sample5 mg
measurements of _________________ samples may be inaccurateirregular shaped
as temperature increases, density _________decreases
memorize

Section 4

Question Answer
oil immersion methodheating under phase contrast microscope until border disappears
becke lineglass placed in oil of known RI
halo forms around glassbecke line
increase working distance ----> becke line moves towards ___________ with higher refractive indexmedium
As temperature increases,RI decreases
As temperature decreasesRI increases
glass breaks on _______ side of impact firstopposite
3R RuleRadial cracks form a right angle on the reverse side of the force
4R Ruleridge lines on radial fractures are at right angles to the rear
radial cracksperpendicular end opposite to radial
concentric cracksperpendicular end on same side concentric
memorize