Level 152 Level 154
Level 153

Radiation & Thermal Stressors


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mutations, cancer, radiation sickness
What are some health effects from ionizing radiation
Alpha radiation
largest radiation particle, helium nucleus - has 2 protons and 2 neutrons; stopped by outer layers of skin; difficult to measure
Beta Radiation
High speed electrons released in the decay process of neutron transforming to a proton
Quality Factor
The factor by which the absorbed dose (in rad or gray) must be multiplied to obtain a quantity that expresses the biological damage (in rem or sievert) to the exposed tissue. AKA radiation weighing factor
20
QF for alpha
1
QF for Gamma
Absorbed dose
The energy imparted to matter by ionizing radiation per unit mass of irradiated material Units: RAD (0.01J/kg)
Dose Equivalent
Rem (radiation equivalent man) claculated by multiplying QF x absorbed dose
100 Rem
Causes an increase of radiation sickness and cancer of 1-5%
500 Rem
Causes death in 50% of exposed persons
Biological effects from radiation occur by
The ionization process that causes either cell mutation or deteroys the cell's ability to reproduce
Radiological half life
The time it takes for 1/2 of the atoms of the substance to decay into another nuclear form
US Dose Rate allowed
5rem/year or 1.25 rem/quarter
ALARA
As low as reasonably achievable
Time distance and shielding
Ways to control radiation exposure
Radiation dose is _______proportional to distance
Inversely - therefore the further you are from the source, the lower the dose you receive
Half value layer
The thickness of a shielding material that attenuates half the photons entering the material
glass and plastic
What are the best materials to shield beta
What is bremsstrahulung radiation
When beta particles hit atoms of a high atomic number (like lead) they create xrays; this is why plastic and glass are preferred shields for beta
Geiger Muller Tube is used for
Radiation surveys works for beta and gama - not suitable for alpha
Scintillation detector
Can be used for alpha beta, gamma. Samples are placed in a vial with scintillation liquid, radiation causes light flashes in liquid which are counted with photomultiplier tube
Non-ionizing radiation
Does not have enough energy to ionize particles
convection
the process whereby heat is transferred by the mass movement of molecules from one place to the other
Radiation
energy that is radiated or transmitted in the form of rays or waves or particles
What is WBGT used for
The wet bulb globe temperature is used to estimate the environmental contribution to heat stress
Symptoms of heat stroke
Body fails to regulate temperature; skin is hot and dry; confused behavior; loss of conciousness; convulsions; medical emergency
Symptoms of heat hyperpyrexia
Less severe form of heat stroke; some sweating still occurs
Symptoms of heat exhaustion
Excessive loss of water through sweating; fatique nausea headache, giddiness; cold clammy skin
Heat cramps
Painful muscle cramps following working in hot environments
Heat rash
Small blister like eruptions during heat exposure; plugged sweat glands, swelling
Heat fatigue
Reduced performance from workers; non-acclimitized workers are most susceptible
Trenchfoot
Several days of exposure to cold (not freezing) temperatures and moist skin resulting in vasoconstriction in feet and legs; pale appearance and numbness
Chilblains
Itching painful reddening of skin; caused by congestion of capillaries when tissues are exposed to cold
Cold Urticaria
Cold can cause histamine releases in body tissue; itchy hives; may cause vomiting, rapid heart rate, swelling of breathing passages
Frostbite
Freezing of body tissue; white or grayish yellow skin; damage depends on depth of freezing
Hypothermia
A condition in which core temperature drops below the required temperature for normal metabolism and body functions (35C or 95F)
1 Becquerel
1 disintigration/sec
1 curie
3.7 x 10^10 disintegration/sec
I2 - I1(d1/d2)^2
Formula for radiation intensity at a distance
WBGT
WBGT = 0.7WB + 0.3 GT (no solar load) OR 0.7WB + 0.2GT= 0.1 DB DB = dry bulb; WB = Wet bulb GT= globe temperature
Heat syncope
Non-acclimitized persons standing in the heat faint; blood flow reduced to brain
What is the maximum sustained heart rate for a 42 year old man?
138 bpm (180 -42) To figure this take 180 bpm and subtract the age