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34 Cards in this Set
- Front
- Back
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Paint coatings |
These Coatings may include electrocoat primer, primer surfacer, base coat, and clear coat |
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Paint spread |
Paint spread onto a surface will dry into a hard film that can be best described as consisting of pigments & additives suspended in the binder |
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What happens if paint smears on an object? |
Paint smeared or embedded in the garments or objects require the whole item to be packaged and sent to the laboratory |
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What is an atom? |
An atom is composed of a nucleus containing protons and neutrons, with electrons found outside the nucleus in electron orbitals |
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What is PDQ database? |
It is a database that identifies the make and model of a car from a small amount of paint and will use colors charts for automobile finishes |
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Solid materials |
Solid material such as paint may be heated or paralyzed to a high temperature so that they will decompose into numerous gaseous products to flow through the GC column |
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Tools |
Tools used to gain entry into buildings or safes often contain traces of paint, requiring the tool to be collected, along with reference paint samples |
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Collection of soil |
Standard reference soils are to be collected at various intervals within a 100 - foot radius of the crime scene, as well as the site of the crime, for comparison to the questioned soil |
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Soil found on the suspect |
Adhering to a shoe or garments must not be removed |
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Define fire |
Chemically, fire is a type of oxidation, which is the combustion of oxygen with other substances to produce new substances. Not all oxidation reactions proceed in a matter that associate with a fire. For example, rusting |
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example of glowing combustion or smoldering |
A cigarette, The Embers of wood fire, or a charcoal fire |
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What are the three mechanisms of heat transfer? |
Production, radiation, and convection |
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What is conduction? |
It is the movement of heat through a solid object poor conductors are called insulators during fire Heat May transported through Metals such as Nails bolts and fasteners to a location far from the initial heat Source creating a new fire |
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What is flashover? |
It occurs when all combustible fuels simultaneously ignite to engulf the entire structure |
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What is convection? |
It is the transfer of heat energy by the movement of molecules within a liquid or gas period and a structural fire, hot gases move to the upper portion of the structure causing surfaces to pyrolyze and burst into a fire |
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What is radiation? |
The transfer of heat energy by electromagnetic radiation. A surface exposed to the heat of a fire May burst into flames when the surface reaches the ignition temperature |
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Indicators of arson |
A fire has a tendency to move in an upward Direction, and thus the probable origin will most likely be the lowest point showing the most intense characteristics of burning |
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Discovery of an ignition device |
The most common igniter is a match the arsonist construct many other types of devices to start a fire. Examples are burning cigarettes, firearm ammunition, a mechanical Matt Stryker, electrical sparking devices comma and a Molotov cocktail |
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Collection of fire scene evidence |
At the suspect point of origin of a fire, ash and soot, along with porous materials which may contain an excess accelerant, should be collected and stored in airtight container such as new paint cans or wide-mouth glass jars, leaving an air space to remove samples. Never use plastic containers to store fire scene evidence |
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What is substrate control? |
A collection of all material suspected of containing volatile liquids must be accompanied by a thorough sampling of similar but uncontaminated control specimens from another area of the fire scene |
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What is headspace? |
A vapor comma laboratory recovery of flammable residues is removed with a syringe |
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What is vapor concentration technique? |
A charcoal strip is placed in the airtight debris container when it is heated. The strip will absorb much of the vapors during Heating then it is washed with a solvent which will recover the accelerant Vapors. Then the solvent is injected into gas chromatograph for analysis |
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When is gas chromatography used? |
In the laboratory, the gas chromatograph is the most sensitive and reliable instrument for detecting and characterizing flammable residues |
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What majority of arsons are initiated by? |
Arsons are initiated by petroleum distillates such as gasoline and kerosene |
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What is most widely used in explosives? |
Black and smokeless powder, and low explosive group |
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What is black powder? |
It is a mixture of potassium or sodium nitrate, charcoal, and sulfur |
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What is smokeless powder? |
It consists of nitrated cotton (nitrocellulose) or nitroglycerin and nitrocellulose |
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What are low explosives? |
Lopes closest are confined to a container like a pipe. The speed of decomposition is called the deflagration causing the walls of the container to fragment and fly outward and all directions |
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What are primary explosives? |
They are Ultra sensitive to heat, shop, or friction and provide the major ingredients found in blasting Caps or primers used to detonate other explosives |
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What are secondary explosives? |
They are relativity and sensitive to heat, shop, or friction and will normally burn rather than detonate if ignited in small quantities in the open air |
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What is trazodone triperoxide? |
Tatp is a homemade explosives that has been used by terrorist organizations. It can be combined with acetone and peroxide in the presence of acid. Its existence has led to the Banning of most liquids on Commercial aircraft. |
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What is a crater? |
A crater is located at the origin and loose soil and other debris is must be preserved from its interior for laboratory analysis |
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When can Conformity identification test be used? |
In the lab, tests may be performed on unexploded materials by infrared spectrophotometry |
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Can recovered debris be rinsed in the lab? |
Yes , recorder debris may also be thoroughly rinsed with Organic solvents and analyzed by testing procedures that include Color Spot test, thin layer chromatography, and gas chromatography-mass spectrometry |
