Appendix C - Glossary
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USER'S GUIDE
This
appendix contains a listing of the terms used in the text and figures of Volume
I. Scroll down through the list or use the alphabetical links below to go
directly to the section where your word is located.
Numerical
5th Percentile Japanese Female
Females
falling at the 5th percentile based on the size of the Japanese female
population. This is the smallest human size considered
for design purposes.
95th Percentile Caucasian Male
Males falling at the 95th
percentile based on the size of the Caucasian male population. This is the largest size considered for design
purposes.
Abduction
The movement of a body segment away from
the midline of the body or body part to which it is attached.
Acceleration
The
rate of change of velocity with respect to time.
Acidosis
Reduction of alkali reserve due to excess
of acid metabolites.
Actuation force
The force required to operate a mechanical
device such as a tool, access door, or fastener.
Acute CO2 Toxicity
Condition of exposure to high-level
concentrations of carbon dioxide; associated physiological response.
Adaptive Response
Change in structure, form, or behavior of
an organism to suit a new environment.
Adduction
The movement of a body segment or segment
combination toward the midline of the body or body part to which it is
attached.
Aerobic Power
Aerobic power is the total amount of power
an individual generates. It is related
to useable power output by an efficiency factor which varies with the task and
the individual.
Alveolar Pressure
Gas pressure existing within alveoli.
Alveoli
The
air-containing
cells of the lungs.
Anatomical Position
A baseline posture for measuring joint
motion range. The posture is standing
upright, head facing forward, arms hanging down with the palms facing forward.
Annoyance
The sense of being troubled, irritated, or
disturbed by unwanted noise.
Anoxia
Hypoxia
especially of such severity as to result in permanent damage.
Anthropometry
Anthropometry is the application of
scientific physical measurement methods to human subjects for the development
of engineering design standards and specific requirements and for evaluation of
engineering drawings, mock-ups, and manufactured products for the purpose of
assuring suitability of these products for the intended user population.
Anxiety
Nervous or fear reaction to perception of
danger.
Astigmatism
A defect of an optical system in
consequence of which rays from a point fail to meet in a focal point resulting
in a blurred and imperfect image.
Atelactasis
Collapsed or airless state of all or part
of the lung.
Atmosphere
1. The mixture of gasses surrounding the Earth or filling the habitable
volume of a spacecraft.
2. The pressure exerted by a column of mercury 760 mm high at 1 G, equal to
101.329 kilopascals.
Top
Beats
A periodic sound resulting from the
interaction of two or more sounds of different frequencies.
Bends
See
Decompression Sickness.
Binary Number System
A base 2 number system using only 1's and
0's. Well suited for electronic logic
where the 1's and 0's can be represented by signal present and signal absent.
Binaural
Of, relating to, or involving both ears.
Biomechanics
Biomechanics is the interdisciplinary
science (comprising mainly anthropometry, mechanics, physiology, and
engineering) of the mechanical structure and behavior of biological
materials. It concerns primarily the
dimensions, composition, and mass properties of body segments; the joints
linking the body segments together; the mobility in the joints; the mechanical
reactions of the body to force fields, vibrations, and impacts; the voluntary
actions of the body in bringing about controlled movements, in applying forces,
torques, energy and power to external objects like controls, tools, and other
equipment.
Bit-Mapped Graphics
The data that defines the pixel color
which is behind the screen pixel.
Blackout
See Graying of
Vision.
Body Envelope
The volume envelope which just encloses
the body and body motions during an activity.
Bolus
Used in this document to designate mass of
fecal discharge.
Bremsstrahlung
1.
Gamma radiation emitted by an electron when
it is deflected by the Coulomb field of an atomic nucleus of charge Z; the
fraction of energy radiated as photons by an electron of initial energy E (Mev)
is approximated numerically by ZE/1000.
2.
The electromagnetic radiation produced by the sudden retardation of a
charged particle in an intense electric field (as of an atomic nucleus); also
: the process that produces such radiation.
Brightness
The amount of light emitted or reflected
from a surface.
Brightness Ratio
The ratio of the luminance of two areas or
surfaces.
British Thermal Unit (Btu)
The amount of heat required to raise 1 lb
of water 60 degrees F, 1 degree F.
Top
A structural housing into which drawers
and shelves are installed. Generally,
there is no utility connections between the cabinet and the items installed
within it. See Housing.
Carcinogenesis
Origin or production of cancer
Periodic irregular heartbeat;
an alteration in rhythm of the heartbeat either in time or force.
Cardiovascular System
Pertaining to the heart and blood vessels.
Cartwheeling
Vernacular descriptive of inertial
resultant of human body to rotational acceleration around the x-axis. (Refer to Figure 5.3.1-1).
Cataractogenesis
The formation of cataracts.
Central Acuity
Center part of the visual field.
Cerebral Hemodynamic Effects
Relating
to or functioning in the mechanics of blood circulation in
the brain.
Chassis Leakage Currents
Currents generated by such internal
sources as filter capacitors terminated to accessible parts or ground, and
capacitive and inductive coupling to accessible parts or ground. These currents can be conveyed form
accessible parts and subsequently applied to a crew member.
Chokes
Syndrome of chest pain, cough, and
respiratory distress.
Chronic CO2Toxicity
Condition of exposure to long-term,
low-level excess concentrations of carbon dioxide, associated physiological
response.
Circadian Rhythms
Bodily functions rhythmically fluctuating
with time. These functions include
heart rate, blood pressure, body temperature, and respiratory volume. Generally, these metabolic functions slow
for a period of time once during a 24 hour period. The most important activity
geared to circadian rhythms is sleep.
CO2Withdrawal
Symptoms arising from cessation of
exposure to excess CO2.
Color Saturation
Saturation is the extent to which an
object has more or less color. Saturation is, therefore, relative colorfulness.
Coma
A
state of profound unconsciousness caused by disease, injury, or poison.
Command Language (command set)
A set of terms, each with a precise
function, used to control the operations of a computer.
The
mucous membrane that lines the inner surface of the eyelids and is continued
over the forepart of the eyeball.
Contaminants
Unwanted material or bacteria.
Continuous Noise
A noise with negligibly small fluctuations
of level within the period of observation
Contrast
The difference between the luminance of an
object or figure C = [(Lc + Lr) - (Ld + Lr)] / (Lc + Ld + 2Lr)
and its immediate background.
C = Contrast
Lc = Object luminance
Ld = Background luminance
Lr = Reflected luminance
Control
A manually operated hardware item used to operate
or change the performance of a machine or system.
Core-Shell Concept
Concept of representing a human as a
heat-producing core surrounded by a shell (skin) through which heat exchange
with the environment takes place.
Coronary Occlusion
Occlusion of a branch of the arterial
system that supplies blood to the heart muscle.
Coulomb Friction
Sliding or kinetic Friction.
Crew Station
Any location where a task or activity is
performed. There are two basic types of
crew stations: workstation and activity center.
Critical Flicker Fusion Frequency
The frequency at which a flashing light
will appear as a steady state light - approximately 65 Hz.
Cyanosis
A
bluish or purplish discoloration (as of skin) due to deficient oxygenation of
the blood.
Top
Dark Adaptation
Dark adaptation is the state of being
adapted (sensitive) to low levels of ambient luminance (brightness). At any one time the visual system operates
well within only a limited range of luminance levels. This range is centered about a particular adaptation level that
is determined by the prevailing luminance. As the prevailing luminance changes the adaptation level will also
change. The adaptation level shifts
more quickly to higher than lower luminance levels.
Dead-Faced
An electrically conductive surface
incapable of supplying sufficient energy under normal conditions to present a
hazard (e.g., the output of a solid-state switch when in the
"STANDBY" state).
A
sometimes fatal disorder that is marked by neuralgic pains and paralysis,
distress in breathing, and often collapse and that is caused by the release of
gas bubbles (as of nitrogen) in tissue upon too rapid decrease in air pressure
after a stay in a compressed atmosphere; called also caisson disease, the
bends.
Default Values
A value or option automatically provided
by the computer system for use in processing when no alternative has been
specified by the operator.
Delirium
A condition of mental confusion, often
with hallucinations.
Denitrogenation
The act of reducing dissolved nitrogen
concentration in tissues, usually by breathing mixture devoid of nitrogen.
Dependent Elbow
The elbow being engorged with blood during
acceleration.
Design Eye Volume
That volume of space in front of a
workstation within which a user's head and eyes should be located to guarantee
visual access to all display information. The design of displays and display layout may be guided by a specified
design eye volume.
Desquamation
To
peel off in scales.
Diluent Gas
Physiologically inert component of an
atmosphere, purpose of which is to reduce oxygen partial pressure.
Direct Contact
The personal contact of a crewmember to electrically
powered surfaces.
Direct Glare
Glare produced by a light source located
within a person's field-of-view.
Display
Hardware item used to present system
information needed by the operator to make decisions for controlling the
system.
Door
Used in Section 8.0, Architecture, to
denote a full opening body passageway. A door opening is closed with a door cover. A door cannot be sealed against a differential pressure.
Double Insulated Enclosure/Chassis
An enclosure/chassis which incorporates an insulation system
comprised of basic insulation and supplementary insulation with the two
insulations physically separated and so arranged that they are not subject to
the same deteriorating influences (e.g., temperature, contaminants, and the
like) to the same degree.
Drawer
A hardware element designed to slide in
and out of a cabinet, rack, or housing. See
Equipment
drawer.
Dry Bulb Temperature
Air temperature measured by a common
thermometer.
Dysbarism
Condition arising from differential pressures
between gas pockets in body and ambient. In this document, considered to indicate greater pressure within body
cavities.
Dysentery
A
disease characterized by severe diarrhea with passage of mucus and blood and
usually caused by infection.
Dyskinesia
Impairment
of voluntary movements resulting in fragmented or jerky motions (as in
Parkinson's disease).
Dysmetria
Dysmetria
is lack of coordination of movement typified by under- or over-shooting the
intended position with the hand, arm or leg. Dysmetria of a hand can make
writing and picking things up difficult or even impossible. Dysmetria that
involves undershooting is called hypometria and overshooting is called
hypermetria.
Dyspnea
Difficult or labored
respiration.
Top
Ear Clearing
Act of equalizing pressure between inner
ear and ambient.
Ebullism
Vaporization of body fluids at body
temperature and low barometric pressure.
Edema
An
abnormal infiltration and excess accumulation of serous fluid in connective
tissue or in a serous cavity (for example, Edematous
Eyelids).
Excessive
accumulation of fluid in eyelids due to the disturbances of fluid exchange.
Effective Temperature
Empirical sensory index accounting for
temperature, humidity and air movement.
Sudden stimulation of the nerves and convulsive
constriction of the muscles caused by the discharge of electricity through the
body.
An
abnormal particle such as an air bubble
circulating in the blood. Compare to Thrombus.
Embolism
Occlusion of a blood vessel. In the case of gas embolism, by a bubble of
gas.
A
condition
characterized by air-filled expansions of body tissues; specifically :
a condition of the lung marked by abnormal dilation of its air spaces and
distension of its walls and frequently by impairment of heart action. See Mediastinal
Emphysema.
Enclosure/Chassis
The outer casing of an
electrical/electronic device.
Enhancement Coding
Any of a variety of techniques used to
enhance, or increase the salience of selected items of information (e.g., color
coding. It is well suited for
interactive computer applications.
Environmental Control
Control of ambient conditions to produce
habitable environments.
A drawer used to house subsystem
components. The installed components
are generally attached to the drawer using fasteners which require tools for
attachment/detachment. It has utility connections to its housing's utility
distribution system.
Erythema
Abnormal
redness of the skin due to capillary congestion.
EVA (Extravehicular Activity)
Activities performed by a space-suited
crewmember in an unpressurized or space environment.
EVA Restraint
A means of stabilizing the EVA crewmember
which requires physical ingress and egress by the crewmember.
EVA Workstation
Any area at which an EVA task is
performed.
Exchange Rate
The increase in sound level (dBA) for
which permissible exposure time is halved.
Exposure Limit
Maximum safe acceleration exposure limit
as a function of vibration frequency and exposure time.
Extension
Straightening or increasing the angle
between the parts of the body.
To
pass by infiltration or effusion from a proper vessel or channel (as a blood
vessel) into surrounding tissue.
Extravehicular Mobility Unit
An independent anthropometric space suit
system that provides crewmembers with environmental protection, life support,
mobility, communications, and visibility while performing various EVAs.
Eyeballs Down
Vernacular descriptive of inertial
resultant of human body to linear acceleration in the upward + Gz vector.
(Refer to Figure 5.3.1-1).
Eyeballs In
Vernacular descriptive of inertial
resultant of human body to linear acceleration in the forward -Gx vector. (Refer to Figure 5.3.1-1).
Eyeballs Left
Vernacular descriptive of inertial
resultant of human body to linear acceleration in the left yaw +Gy vector. (Refer to Figure 5.3.1-1).
Eyeballs Out
Vernacular descriptive of inertial
resultant of human body to linear acceleration in the backward +Gx vector.
(Refer to Figure 5.3.1-1).
Eyeballs Right
Vernacular descriptive of inertial
resultant of human body to linear acceleration in the right yaw -Gy
vector.
(Refer to Figure 5.3.1-1).
Eyeballs Up
Vernacular descriptive of inertial
resultant of human body to linear acceleration in the downward -Gz vector. (Refer to Figure 5.3.1-1).
Top
Facility
Equipment or equipment and the area
dedicated to a specific crew activity. Similar to the term "Center,"
but "Facility" can refer to only equipment without specifying an area
of use. Examples: Shaving Facilities,
Recreation Facility.
Fatigue Decreased Proficiency Boundary
Acceleration boundaries as a function of
vibration and exposure time for the preservation of working efficiency.
Flexion
Bending or decreasing the angle between
the parts of the body.
Follower
The visual movable indicator on a computer video screen that points to or
marks the current position at which a character may be entered.
Foot Restraint
A restraint which stabilizes a crewmember
by providing a platform for immobilizing the feet.
Top
Gas Exchange
The flow of gas through a membrane in the
small air sacs in the lungs to the blood stream and vice versa.
Gas Tension
The partial pressure exerted by a gas.
Glare
A consequence of bright light sources in
the visual field that cause discomfort and/or a decrease in visual
functioning. The effect is worse the
closer the light source is to the line of gaze. The amount of light scattering within the eye (which varies
between individuals effects susceptibility to glare.
Globe Temperature
Physical composite of dry bulb
temperature, radiation, and wind effects measured by placing a temperature
sensing device in the center of a blackened sphere.
Glottis
The
elongated space between the vocal cords; also : the structures
that surround this space.
Due to the draining of blood from the
occipital region of the brain during acceleration, the vision begins to narrow
(tunnel vision) and things appear less bright.
Grayout
See Graying of
Vision.
Grounded Enclosure/Chassis
An enclosure/chassis electrically
connected to the ground return.
Gustatory Sensations
Pertaining to the sense of taste.
Top
Habitable Volume
Habitable volume is defined as free, pressurized
volume, excluding the space required for equipment, fixtures, and stowage.
Handhold,
Handrail
A handle or grasp area which is slightly
larger than the hand and is used as a mobility aid, hand restraint, or as a
hardware mounting surface.
Harmonic
An overtone having a frequency that is an
integral multiple of a given primary tone.
Hatch
Used in this document to denote a full
body passageway. A hatch opening is
closed with a hatch cover. A hatch can
be sealed against a differential pressure.
Heart Arrhythmia
An alteration in rhythm of the heartbeat either in time or force. See Cardiac
Arrhythmia.
Heat Exhaustion
(Also known as heat prostration) - A
syndrome resulting from exposure to high temperatures; characterized by a
moist, cold skin, poor circulation, a normal temperature but elevated rectal
temperature, restlessness and anxiety.
Heat Stroke
The body temperature rises because of
faulty heat dissipation due to high environmental temperature and
humidity. Rectal temperatures may go
from 106 - 100 deg F.
Hematopoietic
Blood
producing. Hematopoiesis is the formation of blood or of blood cells in
the living body.
Hemoglobin
Oxygen carrying cells of the blood.
Hemorrhage
Escape of blood from vessels.
Hexadecimal Number System
A base 16 number system used by computers
in which each digit represents a power of sixteen. For each digit of a hexadecimal number four digits (24=16) of
binary logic are required.
Hierarchical Menu
A set of embedded menus such that entries
in all but the lowest level menu will produce another menu when selected.
A structure into which equipment is
installed. See Cabinet, Rack.
Hyperbaric
Dealing with ambient pressures which are
greater than the gas pressures in the body.
Hyperoxia
Oxygen excess condition arising when
greater than normal oxygen partial pressures are encountered.
Hypobaric
Dealing with ambient pressures which are
less than the gas pressures within the body.
Hypotension
Abnormally
low blood pressure.
Hypothermia
Subnormal temperature of the body.
A
deficiency of oxygen reaching the tissues of the body.
Top
Icon
A symbol that graphically resembles its
intended meaning (e.g., a schematic drawing or a headlight on the control that
is used to control an automobile's headlights).
Illumination
The amount of light (luminance flux)
falling on a surface. Measured in
lumen/m2 lux = 0.093 ft-c. Illumination decreases with the square of the
distance from a point source.
Pulsed or short-duration accelerations of
less than 1 second duration.
Impact Noise
See Impulse Noise.
A noise consisting of one or more bursts
of sound energy, each of a duration less than about one second.
Inaccessible area
Any area with an opening that will accept
a loose and floating object of 10mm (0.4in.) diameter and cannot be retrieved
or captured by using a retrieval tool and/or crewmember reaching their hand and
forearm into the area.
Inclusions
Tiny particles of foreign matter or air
bubbles entrained in glass.
Incontinence
Unable
to retain a bodily discharge (as urine) voluntarily. Inability to control the natural
evacuation of the feces or urine; specifically, involuntary evacuation due to
organic causes.
Sound at frequencies
below the audibility range of the human ear, f 20 Hz.
Indirect Contact
The contact of a crewmember to
electrically powered surfaces through an electrically conducting medium (e.g.,
probe, rod).
In-Line Circuit Leakage Currents
Unintentional currents which can flow in a
conductor. These currents may result
from the inability of solid-state electronics to reach an "infinite"
impedance "OFF" state, as is the ability of a mechanical switch. The solid-state electronic device has a
finite impedance which undesirably completes the input/output circuit thus
providing a means for current to flow. Connections to in-line circuits are normally isolated from crewmember
inadvertent contact by barriers and may be considered a hazard if accessible to
inadvertent crewmember contact. In-line
circuits with leakage currents are
referred to as in "STANDBY" when placed in the high impedance state
since a complete disconnect is not possible and the circuit output is still energized.
Intermittent Noise
A noise whose level suddenly drops to the
level of the background noise several times during the period of observation,
the time during which the level remains at a constant value, different from
that of the ambient being of the order of magnitude of one second or more.
Ischial Tuberoscities
Two bony protuberances in the hip
structure. These bones support a major
portion of the seated body weight in 1-G conditions.
Isolated Patient Contact
A direct or indirect patient contact that
is deliberately separated from the supply circuit and ground by virtue of
spacings, insulation, protective impedance, or a combination thereof (e.g.
intra-aortic pressure monitor).
Isometric Joystick
The isometric joystick, often referred to
as a force joystick or a pressure joystick, is a lever that doesn't move. The output of the isometric joystick is a
function of the amount of force applied to it.
Isotonic Joystick
The isotonic joystick, often referred to
as a displacement joystick, provides an output which is proportional to the
displacement of the joystick from the center.
Top
None
Top
Inflammation of the
cornea of the eye. See Photokeratitis.
Keystone Effect
A distortion in the shape of a projected
image resulting from the film plane and screen plane not being parallel.
Usually, magnification will vary from top to bottom or right to left.
Kinesthetic System
Sensations originating in the sense organs
of the muscles, tendons, and joints that provide us with a sense of relative
body segment movement and position.
Top
Lacrimation
The
secretion of tears especially when abnormal or excessive.
Lateral Rotation
The turning away from the midline of the
body.
Leakage Currents
Unconditional currents which can be
applied to a crewmember.
Level Equivalent or
Leq
Equivalent sound level or
time-average sound level in dB. The
level of steady sound which, in a stated time period and at a stated location,
has the same A-weighted sound in dB energy as the time-varying sound.
Leukopenia
A
condition in which the number of white blood cells circulating in the blood is
abnormally low.
Light scatter fraction
The ratio of scattered light to
specular
reflected light.
Line of sight
The optical axis extending from the
observers eyes to the target viewed.
Line of sight deviation
The angle which the line of sight is
redirected into the eye due to intervening optically refractive material (e.g.,
prism).
Linear Acceleration
The rate of change of velocity of a mass;
the direction of movement of which is kept constant.
Local Vertical
Local vertical is achieved by a consistent
arrangement of vertical cues within a given visual field to provide an
definable demarcation at the crew station boundary within the visual
field. A consistent local vertical
within modules is highly desirable.
Long Term Mission
Any mission in which crewmembers are away
from earth for a period greater than two weeks.
Luminance
The photometric equivalent of the
brightness of an area as viewed from a given direction. More technically,
luminance flux per unit of projected area per unit solid angle. Measured in candela per square meter
(cd/m2), foot-lamberts (ft-L, or millilamberts (mL). 1.0 cd/m2 0.31 mL = 0.29 ft-L. The luminance of a surface does not vary with the distance of the
observer from the surface being viewed.
Luminance Ratio
The difference between the luminance of an
object and its surroundings.
Top
Masking Noise
A background noise or signal with dynamic
range in frequency and level sufficient to obscure another noise or signal from
aural awareness.
Mean Perception
A mild shock perceived by 50% of the
population.
Medial Rotation
The toning toward the midline of the body.
The
space in the chest between the pleural sacs of the lungs that contains all the
viscera of the chest except the lungs and pleurae; also: this
space with its contents.
Accumulation of gas in the tissues of the
chest, specifically in the Mediastinum. Compare
to Emphysema.
Menu
A method for inputting information to a
computer. The menu is a list of the
available input options that may be selected.
Meridional
Of,
relating to, or situated on or along a meridian. A line or a plane which is normal to the
line of sight.
Metabolism
Physiological activity involving
utilization of foodstuffs and oxygen to produce tissues and provide for
production of energy.
Micturition
To
urinate.
Minimal Passageway
A minimal passageway is a translation path
which is only large enough to permit passage of a space suited crewmember with
his or her long axis in the direction of travel.
Mobility Aid
A device (such as a handle) or a surface
(padding which facilitates translation in a microgravity environment.
Top
Narcosis
A state of profound stupor, produced by
toxic effect of certain substances, in diluent gas narcosis, by excessive
partial pressure of diluent.
Narrow Band Noise
A simple or complex tone having intense
and steady state frequency components, relative to wideband noise components,
in a very narrow band (1, of the octave band or 5Hz, whichever is less) and is
heard as a musical sound either harmonic or discordant.
Nausea
Discomfort in stomach with aversion to
food and tendency to vomit.
Neurocirculatory System
Concerned with both nervous and vascular
systems.
Neutral Body Posture
The characteristic posture that the
relaxed human body assumes in microgravity.
No Sensation
The level of perception only perceived by a fractional percentage of the
population.
Noise Canceling
A technique to delete, neutralize, or
counteract any unwanted electrical signal within a communication system that
interferes with the sound or image being communicated.
Noise Shields
The physical coverings or shells used to
protect or screen any unwanted electrical signal within a communication system
that interferes with the sound or image being communicated.
Non-adaptive Response
Pathological response to a new environment
which presents conditions beyond an organisms ability to adapt.
Normoxic
Having a normal level of oxygen.
Neurocirculatory collapse
R psychosomatic disorder characterized by
dyspnea, palpitation, vertigo, faintness, fatigue. Tremor, caused by stress, fear, and violent exercise.
Top
Octal Number System
A base 8 number system in which each digit
represents a power of eight. For each
digit of an octal number three digits (23 = 8 of binary logic are required.
Octave Band
The band of frequencies where the highest
frequency is twice that of the lowest frequency.
One-Third Octave Band
The band of frequencies In which the ratio
of the extreme frequencies is equal to the cubic root of 2: i.e.
fn/fe 1.260, where fn and fe are the highest and lowest cutoff
frequencies of the band.
Orbital Replacement Unit (ORU)
A piece of equipment (a single item or
module containing an assembly of components) which is designed for removal and
replacement as a unit.
Ordinary Patient Connection
A direct patient contact that does not
have the spacing, insulation, or protective impedance associated with an
isolated patient connection (e.g., blood pressure cuff).
Orthostatic Intolerance
Difficulty in standing erect in a l-G
environment. This could be due to any
number of effects of exposure to microgravity (cardiovascular, muscular,
skeletal, or coordination.
ORU Chassis Leakage Currents
Currents generated by such internal
sources as filter capacitors terminated to accessible parts or ground, and
capacitive and inductive coupling to accessible parts or ground. These currents can be conveyed from accessible
parts to ground or other accessible parts and subsequently applied to a
crewmember.
Overall SPL
Overall SPL (Sound Pressure Level) is
interpreted as including all noise within the frequency range from 22.4 to
11,200 Hz.
Oxygen Atelectasis
Collapse
of the expanded lung.
Oxygen Toxicity
Toxic effects of excess oxygen partial
pressure.
Top
Parallax Error
The perceived change in relative position
of objects at different distances from an observer when viewed from different
positions. Can cause errors in the
reading of some instruments.
Paresthesias
A sensation of tingling, crawling, or
burning of the skin that has no objective cause.
Paroxysm
A
fit, attack, or sudden increase or recurrence of symptoms
Pass-Through
A pass-through is a translation path which
is only large enough to permit passage by an IVA clothed crewmember with his or
her long axis in the direction of travel.
Passageway
A pass-through area between non-adjacent
modules or spaces.
Patient
A crewmember instrumented with
electrical/electronic equipment.
Patient Connection Leakage Current
Leakage currents measured between patient
leads at the patient interface, or between patient leads at the patient
interface and ground.
Pattern Coding
A perceptual indicator used to
differentiate areas of interest to the observer, or reduce operator search
time.
Peak Pressure Level
Peak sound pressure for any specified time
interval is the maximum absolute value of the instantaneous sound pressure in
that interval.
Percentile
A point on a scale indicating the
percentage of persons within a population who have a body dimension of a
certain size or smaller. The value of
the statistical variable that marks the boundary between the consecutive
intervals in a distribution of 100 intervals, each containing one percent of
the total population.
Perception
The
awareness
of the elements of environment through physical sensation such as perceiving a mild shock.
Perfusional changes
Changes in the
flow rate of blood in blood
vessels.
Petechial Hemorrhages
A
minute reddish or purplish spot containing blood that appears in skin, mucous
membrane, serous membrane, or on a cross-sectional
surf ace of an organ
especially in some infectious diseases.
Photokeratoconjunctivitis
Photochemical
injury to the cornea of the eye by ultraviolet exposure may result in
photokeratoconjunctivitis. This painful condition may last for several days and
is very debilitating; called also welders flash, snow blindness.
See Conjunctiva.
Photokeratitis
is essentially a reversible sunburn of the cornea resulting from excessive UV-B
exposure. It occurs when someone spends hours on the beach or snow without eye
protection. It can be extremely painful for one to two days and can result
in temporary loss of vision. See Keratitis.
Physiologically Inert
Substance that does not Interact
chemically with the body.
Physiology
The
organic processes and phenomena of an organism or any of its parts or of a
particular bodily process.
Pixel Addressability
The capability to store or retrieve from,
a specific location in memory, the basic unit or picture element that makes up
the image displayed in a video screen.
Pleura
The
delicate serous membrane that lines each half of the thorax of mammals and is
folded back over the surface of the lung of the same side.
This membrane
envelopes the lung and lining
the thoracic cavity.
Pneumothorax
A
condition in which air or other gas is present in the pleural cavity and which
occurs spontaneously as a result of disease or injury of lung tissue or puncture
of the chest wall or is induced as a therapeutic measure to collapse the lung
Postrun Headache
Headache that occurs after an event.
Predicted Four-hour Sweat Rate
Empirical index incorporating environment,
work and clothing to predict sweat production.
Pre-Emphasis
The intentional alteration of the relative
strengths of signals at different frequencies (as in radio and in disc
recording) to reduce adverse effects (as noise) in the following parts of the
system.
Primary Passageway
A primary passageway is a translation path
which accommodates a space suited crewmember in an upright working position or
neutral body posture.
Prompt
A message or other signal displayed on a
computer generated display advising the operator that he or she is expected to
provide some specific response.
Pronation
The
rotation of the hand and forearm so that the palm faces backwards or downwards.
Proxemics
The
study of the nature, degree, and effect of the spatial separation individuals
naturally maintain (as in various social and interpersonal situations) and of
how this separation relates to environmental and cultural factors.
Proximity Operations
Any space module related activity that is performed outside the space module and within a specified boundary.
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None
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R value
Ratio of initial nitrogen partial pressure
to the final total pressure.
A structure into which equipment drawers
or other types of equipment mounting hardware is installed. A rack generally has a built-in utility
distribution system that provides interfaces far connecting the installed
equipment's utilities.
Random Noise
A sound whose instantaneous amplitudes
occur, as a function of time, according to a normal (Gaussian) distribution
curve. Random noise need not have a
uniform frequency spectrum.
Reaction Time
The time between the presentation of a
stimulus and the beginning of a response to that stimulus.
Reduced Comfort Boundary
Acceleration boundaries as a function of
vibration and exposure time for the preservation of comfort.
Remote Operation
An operation which permits personnel to
send and receive information or commands to a distant environment.
Replacement Unit
General term that includes Orbital
replacement units (ORU), Line replacement units (LRU), and Shop replacement
units (SRU).
Respiration
The series of actions resulting in the
supply of oxygen to tissues of the body.
Response Time
The time interval during which the actual
response to the stimulus is accomplished.
Restraint
A mechanism for restricting unwanted movements
of an object or a person in microgravity environments. Restraints can be mechanical (such as a
strap) or non-mechanical (magnetism or vacuum.
Reverberation Time
Time required for the average sound energy
density in an enclosure to decrease to -60 d B of the initial value after the
source has stopped.
Roentgen Equivalents, Man
The absorbed dose of any ionizing
radiation which produces the same biological effects in crewmembers as those
resulting from the absorption of 1 roentgen of x-rays.
Rotational Acceleration
The rate of change of the direction of a
mass, the velocity of which is kept constant. In this regard, the rotational acceleration is directly proportional to
the square of the velocity and inversely proportional to the radius of the
turn.
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Sacrificial surfaces
A protective surface placed over a
delicate surface which will absorb environmental damage.
Scrolling
An operation or facility of a VDT in which
display elements make a continuous bottom-to-top vertical movement across the
screen (or window) under control of the operator, with display lines appearing
at the bottom edge and dropping off at the top.
Segment
A body segment is the largest dimensional
mass which when moved will maintain a constant geometry.
Shock
Physical or emotional trauma; clinical
manifestations of inadequate amount of circulating blood. See Impact
Acceleration.
Shock - Electrical
See Electrical Shock
Shock Load
See Impact Acceleration
Signal-To-Noise Ratio
The ratio of the amplitude of the signal
transmitted through an instrumentation system to the amplitude of the noise
generated within the system.
Somersaulting
Vernacular descriptive of inertial
resultant of human body to rotational acceleration around the y-axis. (Refer to Figure 5.3.1-1).
1.
Relating to the speed of sound in air (about 761 miles per hour or 1224
kilometers per hour) at sea level at 59°F (15°C).
2.
Sound at frequencies with the human ear's audibility limit (between 20 Hz and
20KHz). See Ultrasonic, Infrasonic.
Space Module
An inhabited establishment away from the
earth.
Space Motion Sickness
A malady occurring in approximately 50, of
people initially exposed to microgravity. Symptoms are similar to that of motion sickness and last 2-4 days. To date, susceptibility to space motion
sickness has not been predictable from responses In a l-G environment. Only limited success has been achieved in
controlling space motion sickness.
Specular
Of,
relating to, or having the qualities of a mirror.
Specular Glare
Glare which is created by the image of a
light source reflecting off a surface within a person's field-of-view.
The reflected image of the light source
corresponds very closely in size and shape to the original light source.
Speech Interference Level
The background or sound noise level in dB
at frequencies between 150 and 7500 Hz that will result in the loss of
intelligibility conversation.
Squeeze
Condition arising when gas pocket is
compressed to a smaller size than its normal residual volume.
Standby
A high impedance state of an electronic
device, usually to minimize the amount of energy consumed or supplied (e.g.,
the off state of an electronic switch).
Standard Passageway
A standard passageway is a translation path
which accommodates an IVA clothed crewmember in an upright working position or
neutral body posture.
Stroke
Common term for apoplexy; hemorrhage into
the brain, causing sudden onset of coma and neurological signs.
Subcutaneous Emphysema
Accumulation of gas under the surface of
the skin.
Suffusion
1.
To spread over or through in the manner of fluid or light.
2.
A spreading or flow of any fluid of the
body into surrounding tissue; an extensive superficial extravasation of blood.
Supination
The
rotation of the forearm and hand so that the palm faces forward or upward and
the radius lies parallel to the ulna
Symbol
A character or graphic that stands for or
represents - something else such as operations, quantities, elements, relations,
or qualities.
Syncope
The
loss
of consciousness resulting from insufficient blood flow to the brain.
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Teleoperator
A remotely controlled mobility module which
incorporates sensory and manipulative subsystems for the purpose of extending
the human operator's skills and
cognitive capabilities into hostile or remote environments.
Tether
A hook and lanyard which is used to attach
a crewmember or a piece of hardware to a piece of hardware.
Thermal Comfort
That condition of mind which expresses
satisfaction with the thermal environment. Specifically, when the core temperature is normal, and the rate of body
heat storage is zero.
Thermogenesis
The
production of
heat, for example, muscular heat production by shivering.
Thermoregulation
Regulation of temperature, particularly
self-regulation of body temperature.
Thrombocytopenia
Persistent
decrease in the number of blood platelets that is often associated with
hemorrhagic conditions.
A
clot of blood formed within a blood vessel and remaining attached to its place
of origin. Compare
to Embolus.
Tinnitus
A
sensation of noise (as a ringing or roaring) that is caused by a bodily
condition (as a disturbance of the auditory nerve or wax in the ear) and can
usually be heard only by the one affected.
Tissue
An
aggregate of cells usually of a particular kind together with their
intercellular substance that form one of the structural materials of a plant or
an animal.
Touch Temperature
Temperature of objects in direct physical contact.
Toxicity
The quality of poison; the kind and amount
of poison produced by a microorganism.
Tracheal Pressure
Gas pressure existing within the trachea
(wind pipe).
Translation
To move from one place to another by use
of reaction power.
Transmissivity
The proportion of luminous flux which
passes completely through a window to the eyes or sensor to the amount of
luminous flux incident upon the outside of the window.
Troland
Retinal illuminance resulting from viewing
a surface with a luminance of 1 cd/m2 through an artificial pupil with an area of lmm2.
Tunnel
A passageway which allows the crewmember
to move only along his/her longitudinal axis.
Twist
Vernacular descriptive of inertial
resultant of human body to rotational acceleration around the z-axis. (Refer to Figure 5.3.1-1).
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Ultrasonic
Sound
at frequencies above the human ear's audibility limit of about 20,000 hertz --
used of waves and vibrations.
Urethra
The canal that carries urine from the
bladder.
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Vasoconstriction
Narrowing
of the
blood vessels in order to
decrease blood flow to the skin to preserve body heat.
Vasodilation
(Variant: Vasodilatation)
Widening
of
the blood vessels to allow
increased blood flow to the skin to promote heat loss.
Vestibular System
Located in the inner ear, the vestibular
system is responsible for the sense of balance (and relative position of the
body with respect to the environment). The vestibular system senses
acceleration and direction of gravity.
Viewport
A transparency located such that an
observer can see from one compartment into another.
Visual acuity
Refers
to the smallest resolvable detail an observer
can see.
Visual Angle
The angle formed at the eye by two
imaginary lines drawn to either side of the object in question.
Visual Clutter
Visual clutter results when the quantity
of information in a visual display becomes great enough so that it starts to
result in information overload. Accuracy and speed of performance will decline
as visual clutter increases.
Visual Display Terminal
An electronic device used to present
visual information - that is usually computer generated. They are used in
conjunction width both the Input and output of information. Examples include: cathode ray tub (CRT), liquid crystal diode (LCD, light emitting
diode (LED), plasma, and electro-luminescent (EL).
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Wavefront Deviation
Any change in the reflected wavefront of a
set of rays as compared with the incident wavefront of the same set.
Wet Bulb Glove Temperature
Calculated refinement of globe temperature
by weighting dry bulb and wet bulb temperatures with the standard globe
temperature.
Wet/Dry Index
Calculated prediction of human stress
temperature accounting for wet and dry bulb temperatures.
Wing Tab Connector
An electrical utilities or other connector
with two opposed radial tabs to facilitate EVA connect or disconnect.
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X-axis
The
axis of a plane Cartesian coordinate system parallel to which ordinates are
measured. This refers to the direction of back to chest, anatomically.
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Y-axis
The axis of a plane Cartesian coordinate system parallel to which ordinates are
measured. This refers to the direction of right to left side, anatomically.
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Z-axis
The axis of a plane Cartesian coordinate system parallel to which ordinates are
measured. This refers to the direction of foot or buttocks to head,
anatomically.
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