FRNSC 410 Quiz #1

Reflective Ultraviolet Imaging System

Backronym of RUVIS and is used to illuminate small items and/or surfaces.

Light Amplification by Stimulated Emission of Radiation

Backronym of LASER and has the advantages of having high intensity and defined operational wavelengths, but has the disadvantages of having limited flexibility with wavelength settings and is typically expensive.

High-Intensity Tunable-Wavelength Light Source

The backronym of HITWLS, this light source that has the advantages of a greater flexibility of wavelength settings and is less expensive than a laser, but has the disadvantage of a lower intensity than a laser.

Forensic Light Source

The backronym of FLS, it is another name used for a HITWLS.

Alternate Light Source

The backronym of ALS, it is another name used for a HITWLS.

lamp

A component of a HITWLS, this object offers an intense, white illumination source using xenon and produces wavelengths in the UV and VIS ranges.

cold mirror

A component of a HITWLS, this object is able to transmit UV and VIS light, but blocks IR.

bandpass filter

A component of a HITWLS, this item is able to "tune" wavelengths, which passes frequencies within a certain range and rejects frequencies outside that range.

collimation lens

A component of a HITWLS, this object focuses light into a light guide.

light guide

A component of a HITWLS, this object is composed of a single-core liquid or fiber optic bundles.

focusing lens

A component of a HITWLS, this object is able to provide uniform illumination with sharp edges. It permits range changes, also known as spot size, from being distant to close up.

central wavelength

This is the selected wavelength that describes the wavelength that is at the center of the range of a filter being used.

bandwidth

This is measured at half maximum and referred to as the full width at half maximum.

full width at half maximum

The backronym of FWHM. It is associated with the bandwidth of a HITWLS device. It is where the filter transmits at least 50% of light at the central wavelength.

dark

The type of lighting environment a HITWLS should be used in.

415 nm

The wavelength where blood exhibits the strongest absorption.

common IR sources

Incandescent lamps (tungsten and quartz-halogen), HITWLS (requires IR port), and sunlight are all considered this.

heat fixation

This type of blood fixing is challenging to perform at a scene and aids the adherence of a specimen to its underlying surface.

chemical fixation

This type of blood fixing is more frequently used and is less challenging to perform at a scene. Common fixatives are 5-sulfosalicylic acid and menthol, ethanol, and acetone.

ballistics

The study of the dynamics or flight characteristics of projectiles. It is primarily concerned in reconstruction of shooting events.

interior ballistics

The study of projectile behavior from propellant ignition to barrel exit.

transitional ballistics

The study of projectile behavior from barrel exit to point where pressure behind the projectile is equalized. It is the intermediate stage between interior and exterior ballistics.

exterior ballistics

The study of projectile behavior from the point where pressure behind the projectile is equalized to substrate interaction.

terminal ballistics

The study of projectile interaction with objects and other materials.

firearm safety rules

The following numbered list refers to this:

1. Treat all firearms as if they were loaded 2 Never let the muzzle cover anything you are not willing to destroy

2. Keep your finger off the trigger until your sights are on the target

3. Identify your target, and what is behind it.

Jeff Cooper

The name of the man who created the "firearm safety rules."

loaded

The gun is considered this when there are one or more bullets in the cartridge.

unloaded

The gun can only be considered this when there are no bullets in the cartridge.

rifled barrel

This type of firearm is designed to fire one projectile. It includes gun types such as: pistols, rifles, submachine guns, and machine guns. The barrels of these guns have lands and grooves.

smooth-bore barrel

This type of firearm is designed to fire multiple projectiles. It includes a shotgun as the type of gun. The barrels of these guns are smooth.

pistol

This type of gun is a single-shot gun and includes subtypes such as: revolvers, self-loading guns, and automatics.

swing-out cylinder

Some revolvers have this feature where the cylinder of the gun can be reloaded by swinging out the cylinder to the left or right.

blowback

A semi-automatic operation where the bolt and barrel of the gun are not locked and are held together by recoil spring pressure.

recoil operation

A semi-automatic operation where the bolt and barrel are locked and remain locked for some distance after discharge.

hammer

This is a component of the firing mechanism, which strikes the firing pin.

firing pin

This is a component of the firing mechanism, which strikes the primer or ridge of the cartridge.

striker

This is a spring-driven rod-like firing pin, or a component that impacts the firing pin, which travels in linear path to strike the primer.

single action only

This is an action type where the hammer must be cocked to discharge firearm.

double action only

This is an action type where the firearm can be discharged only with a trigger pull. If the hammer of the gun is present, it cannot be cocked.

single action/double action

This is an action type where the firearm can be discharged using either single action or double action. In semiautomatic firearms that have a hammer present, it is cocked during slide movement.

rifle

This type of firearm is either a single shot, pump action, lever action, or bolt action

single shot rifle

This is a firearm that holds only a single round of ammunition, and must be reloaded manually after every shot.

lever action

This is a design wherein the breech mechanism is cycled by an external lever generally below the receiver.

bolt action

This type of rifle is a type of manual firearm action that is operated by directly manipulating the bolt via a bolt handle, which is most commonly placed on the right-hand side of the weapon (as most users are right-handed).

turn bolt

This is another term for "bolt action."

gas operated semi-automatic

With this type of rifle, the expanding gases from the shell move up the barrel into a gas port that regulates how much pressure is exerted against a piston under the fore end. This piston drives back the bolt to cycle the shotgun for the next shot.

clip

This is a device that is used to store multiple rounds of ammunition together as a unit for insertion into the magazine or cylinder of a firearm. Some styles of this device are stripper, full moon, and half-moon.

magazine

This is a container that holds cartridges under spring pressure to be fed into the gun's chamber. It is not the same as a clip.

submachine gun

This firearm is an automatic gun and fires pistol ammunition. These firearms are normally compact, and intended to be used at close combat ranges.

machine gun

This firearm is an automatic gun that fires bullets in rapid succession for as long as the trigger is pressed. This firearm is for military use and needs to be propped on steady ground and fires rifle ammunition.

shotgun

This type of firearm has a long barrel designed to shoot a straight-walled cartridge known as a shotshell, which usually discharges numerous small pellet-like spherical sub-projectiles called shot, or sometimes a single solid projectile called a slug.

aperture sight

This sighting device is a combination of a bead or post front sight and a round hole set on the rifle's receiver close to the shooter's eye.

telescopic sight

This sighting device consists of a main tube with lenses to magnify distant objects, it has line reticles for lining up the center of a target. This sight is mounted on top of the barrel or action of a firearm.

holographic sight

This sighting device uses a non-magnifying gunsight that allows the user to look through a glass optical window and see a holographic reticle image superimposed at a distance on the field of view.

broaching

This type of barrel rifling method that uses a toothed tool to remove material, resulting in lands and grooves inside the barrel of the firearm.

swaging

This is a rifling method in which a rifling button is forced down a drilled-out barrel blank. The button simultaneously expands the barrel to its final diameter and embosses the lands and grooves on the interior.

hammer forging

This is a rifling method in which a barrel blank is hammered down over a mandrel. This method is used to make polygonal rifling.

electrochemical etching

This is a rifling method in which the grooves of the rifling are produced by an electrochemical process. The barrel and probe are immersed in an electrolyte (NaNO3) solution.

gauge

The bore diameter of a barrel is expressed as this form of measurement, determined by the number of lead balls of size equal to the approximate diameter of the bore that it takes to weigh one pound.

choke

This is an interior constriction placed at or near the muzzle end of a shotgun's barrel to control shot dispersion. The tighter this is constriction is, the more controlled the shot dispersion is and the further distance it will travel.

bore diameter

This is the diameter of the circle formed by the tops of the lands inside the barrel of a rifled firearm.

caliber

The diameter of the bore measured from land to land. Not the same thing as bore diameter.

410

What is the only shotgun that doesn't use gauge?

ammunition

Designed to be fired out of rifled barrels and smooth-bore barrels. Cartridges can be rifled and shot out of shotguns.

primer

An explosive chemical compound that ignites gunpowder when struck by a firing pin. May be placed in rim of the case of in the center of the base.

projectile

The object expelled from the barrel. A bullet is one of these. Commonly is a copper jacket.

propellant

Sometimes called gunpowder. Classified as an explosive. Produces thick vapor, draws moisture, and thus rusts parts of a gun. Combusts rapidly, but does not detonate. More of this is added than needed in order to make sure the projectile is ejected fully from the barrel.

cartridge

Also called a round. A type of pre-assembled firearm ammunition packaging a projectile and its components.

single-base

A type of smokeless powder composed of nitrocellulose, stabilizers, and additional additives. Manufactured by the nitration of cellulose.

double-base

A type of smokeless powder composed of nitrocellulose, nitroglycerin, stabilizers, and additional additives.

triple-base

A type of smokeless powder utilized by the military.

powder granules

Ball, disc, rod, and lamel are all used to describe geometries of what? These shapes are used to control burn rate.

modern primers

Lead styphnate, antimony sulfide, and barium nitrate are all common constituents of what?

Sintox

This lead-free primer is designed to eliminate lead vapors.

head stamp

These indicate the manufacturer of a bullet among other information.

wad

This is part of a shot shell that is designed to produce more consistent patterns by protecting the shot and ensuring reliable powder combustion.

birdshot pellets

Another term for smaller shot sizes.

buckshot pellets

Another term for larger shot sizes.

unload it

What should you do with a firearm before packaging it as evidence?

if gun is loaded

What is the first thing you should check for when you see a firearm on scene?

recorded and photographed

Condition of firearm upon discovery must be ______ and _______

gunshot residue

The backronym of GSR. This includes all residue produced from firearm discharge. Some sources include primer, propellants, and projectiles.

lead styphnate

This chemical is the most common initiating explosive in primer and is a source of GSR.

barium nitrate

This chemical is the most common oxidizing agent in primer and is a source of GSR.

antimony sulfide

This chemical is the most common fuel in primer and is a source of GSR.

Tetracene

This chemical is the most common sensitizer in primer and is a source of GSR.

organic and inorganic

GSR components are separated into two chemical categories. What are they?

SEM/EDX

The most commonly used instrumental method to detect GSR in the lab.

light background

This type of background should be used when using and intense, white illumination to visualize GSR patterns. Stereomicroscopy or other magnification can be used with this type of illumination as well.

dark background

This type of background should be used when using IR illumination techniques, HITWLS, and radiography to visualize GSR patterns.

400-555 nm

This wavelength range (VIS) from a HITWLS should be used for visualizing GSR patterns in order to cause the substance to fluoresce.

nondestructive

If you want to try and visualize GSR on a dark background, what type of techniques should you use first?

diphenylamine

This is a test that tests for nitrates and nitrites, resulting in a product that is blue in color. Some disadvantages include it being very corrosive and not only reacting to one oxidizing agent.

modified Griess test

The backronym of MGT, this is a test for nitrites only. To perform this test, test it on patterns and spots.

sodium rhodizonate test

This test is used to detect lead. It is conducted by dampening filter paper with 15% acetic acid and pressing it onto material, producing a scarlet color if it is positive.

dithiooxamide test

This is a test for copper and nickel. To perform this test, first dampen filter paper with ammonium hydroxide and press it to material. A color change will occur. Green indicates copper, blue or pink indicate nickel.

bullet impact mark

The backronym of BIM. Based on Locard's exchange principle in the way that material from the projectile it transferred to the substrate and vice versa.

ejecta cloud

Produced upon impact between projectile and substrate. May contain material from both the projectile and substrate.

two hours

Within what time frame can significant amounts of GSR be lost from the skin?

swabbing

A method of GSR collection that involves different types of swabs and filter paper moistened with solvent to sample areas. Materials are then extracted and analyzed.