Bio/Trace Quiz 2

What type of paint analysis would tend to give the highest evidential value

physical fit

What 3 types of glands found on the skin which can contribute to latent fingermark residue

Eccrine, Sebaceous, Apocrine

Forensic Palynology

spores and pollen

Soil profile

a vertical section through a soil showing the multiple horizontal layers

What is an advantage of visual examination of fingermarks

non-destructive

Fluorescence

absorbs light of a specific wavelength and emits light at a longer wavelength

What treatment is best for wet exhibits

physical developer

inorganic component of GSR

lead, barium, antimony, copper and iron

Ninhydrin colour results

Ruhemann’s purple

Triangle of Interaction

Environment, surface and fingermark composition

Physical properties of glass

refractive index and density

The particular behaviour of the projectile when it meets its target/body

Terminal balistics

Forensic ecology

recovery and analysis of plants from a crime scene

Trichomes

used for plant identification

Photoliths

silica bodies found in plant tissues and vary with species

Palynology

study of pollen

Pollen

has resilient coat (exine) making it resistant to chemical degradation and produced by conifer and angiosperms

Entomophilous

insect-pollinated species

Anemophilous

wind-pollinated species

Hydrophilous

underwater-pollinated species

Types of pollen

pine, willow and dandelion

Pollen sampling

small pinch samples should be taken off the surface soil and stored in an airtight container

Soil

composed of minerals and eroded bits of rock

Soil classification

colour, texture, composition and pH

Diatoms

unicellular algae found in marina and fresh water made of crystallised silica

Basic soil analysis

sieving soil into fractions, different particle sizes will embed into different layers (dry and wet)

Fingermarks

traces left unknowingly by a person on an object (visible, plastic ,latent)

Fingerprint

record or comparison print taken for identification, exclusion or database purposes (loops, arches and whorls)

Loops

60-65% curves around and exits the same side

Whorls

30-35% central pocket loop

Arches

5%

Latent fingermarks

can’t be seen with the naked eye; made from body oil, grease and water

Visible fingermarks

an appropriate substance is transferred by the fingertips onto a suitable surface

Plastic fingermarks

reasonably visible to the naked eye

Visualisation and enhancement

to enhance ridge detail and improve chance of identification

Non-porous substrates

Type of surface that doesn't allow liquids or gases to pass through, such as glass or metal.

Semi-porous substrates

Type of surface that allows some but not all liquids to penetrate. Examples include wood, concrete, and some types of stone.

Porous substrates

Material with small holes or spaces that allow liquids or gases to pass through. Common examples include sponges, filter paper,

Henry system

ten-print classification system

Ninhydrin/DFO

used to reveal prints by reacting with amino acids and amine groups

Physical developer

silver-based aqueous reagent that targets sebaceous components

Superglue (cyanoacrylate) fuming

vapour polymerises on latent fingermarks and white deposit produced

Ballistics

study of projectile and factors affecting them

Gunshot residue (GSR)

a heterogenous cloud of finely divided particles

Internal ballistics

event occurring from ignition to gun barrel

Intermediate ballistics

when projectile leaves muzzle to pressure behind it (muzzle flash, sound)

External ballistics

flight of bullet before it strikes target

Individual characteristics of guns

same weapons bullets, same marks

Range of firing

distance from target and shooter

Lubricants

smoothen movement of projectile

Organic GSR (OGSR)

bases (nitrocellulose, lubricants)

Barrel temperature

200-300 degrees

GSR deposition

found on the hand and body of the shooter

GSR qualitative analysis

colour tests. destructive, large amounts required and unreliable

GSR quantitive analysis

instrument techniques

Contact shot

muzzle imprint can be used to identify shape of barrel and gun

Close range shot

GSR found around central wound , dirt ring formed from grease

Intermediate range shot

Tattooing, depositing of GSR particles under skin of victims

Distance range shot

mistaken for exit wound

Documents class characteristics

writing features common to group or language

Document individual characteristics

letters depart from usual copybook form

Copybook form

the standard

Ballpoint pen mechanism

glycol based; ball-in housing which is attached to an ink chamber

Gel pen mechanism

water based; pigments rather than dyes

Ink gooping

deposition on paper of blob of accumulated ink from a ballpoint pen

Paper

made of cellulose fibres with addition of other components such as binders and optical brighteners

Glass

class of hard brittle materials that are manufactured by cooling melts, consists of silica and other oxides

Annealing

slowly and evenly cooling glass down to normal temperature to stop internal stresses

Annealed glass

simplest form of glass

Toughened glass

resistant to breakage and produces large shards

Fully tempered glass

resistant to breakage and produces small shards

Laminated glass

sandwiched in plastic

Micrometre

use to measure thickness of glass to a high degree

Mohs scale

indicates substances hardness relative to other substances

Compression

pushing down of force

Shear

move in opposite directions

Tensile

a pulling force

Loaded side

side of glass that experiences compression forms tensile strains

Unloaded side

experiences tensile force and forms compression strains

Radial cracks

develop on the exit side

Concentric cracks

form circular patterns and develop on entrance side

Rib marks

come from point of entry and curve away

Refractive index

how the light bends as it enters the glass

Paint

composed of additives, pigments, solvents and binders

collection of paint evidence

suitably sized and separate container

When was MIRSAP introduced

2005