exposure

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exposure

1. Archit the position or outlook of a house, building, etc.; aspect
2. Mountaineering the degree to which a climb, etc. is exposed (see exposed (sense 4))
3. Photog
a. the act of exposing a photographic film or plate to light, X-rays, etc.
b. an area on a film or plate that has been exposed to light, etc.
c. (as modifier): exposure control
4. Photog
a. the intensity of light falling on a photographic film or plate multiplied by the time for which it is exposed
b. a combination of lens aperture and shutter speed used in taking a photograph

Exposure

The area on any roofing material that is left exposed to the elements.

Exposure

 

in photography, the quantity of illumination H (a photometric quantity), which serves as an evaluation of the surface density of the luminous energy Q. It determines the effect of optical radiation on the photographic material used.

In the general case, H = dQIdA = ∫Edt, where A is the illuminated area, E is the illuminance, and I is the duration of irradiation (exposure time). If E is a constant, then H = Et. In the SI system (seeINTERNATIONAL SYSTEM OF UNITS), exposure is expressed in lux-seconds (lx-s). Beyond the limits of the visible portion of the radiation spectrum, the quantity used is the energy exposure, which is the product of the irradiance and the duration of irradiation; it is expressed in joules per m2 (J/m2).

It is convenient to use the concept of exposure if the effect of radiation is cumulative over time (in photography as well as, for example, in photobiology). The concept is widely used in work with nonoptical and even corpuscular radiation, such as X rays and gamma rays (where the exposure is defined as the product of the surface density of the radiation flux and the duration (), as well as streams of electrons and other particles (where the exposure is equal to the product of the radiation dose rate and t). (See alsoSENSITOMETRY and CHARACTERISTIC CURVE.)

A. L. KARTUZHANSKH

exposure

[ik′spō·zhər]
(building construction)
The distance from the butt of one shingle to the butt of the shingle above it, or the amount of a shingle that is seen.
(graphic arts)
The act of permitting light to fall upon a photosensitive material.
(medicine)
The state of being open to some action or influence that may affect detrimentally, as cold, disease, or wetness.
(meteorology)
The general surroundings of a site, with special reference to its openness to winds and sunshine.
(nucleonics)
The total quantity of radiation at a given point, measured in air.
The cumulative amount of radiation exposure to which nuclear fuel has been subjected in a nuclear reactor; usually expressed in terms of the thermal energy produced by the reactor per ton of fuel initially present, as megawatt days per ton.

shake

A thick wood shingle, usually formed either by hand-splitting a short log into tapered radial sections or by sawing; usually attached in overlapping rows on wood sheathing, 1 as a covering for a roof or wall.

exposure

i. The total quantity of light received per unit area on a sensitized plate or film. It may be expressed as the product of the light intensity and the exposure time.
ii. The act of exposing a light-sensitive material to a light source.
iii. One individual picture of a strip of photographs, usually called a frame.

exposure

(1) The degree to which information can be accessed using authorized or unauthorized methods. See penetration test and risk analysis.

(2) In a camera, the amount of light that reaches the film (analog) or CCD or CMOS sensor (digital). The exposure is achieved by the sum of the shutter speed, aperture (f-stop) and ISO setting. See shutter speed, f-stop and ISO speed.
References in periodicals archive ?
Seawater in 12 containers with abalone in a 1-ton indoor FRP tank was completely drained and subjected to air exposure for 30 h at room temperature.
Dynamic changes of temperature were monitored in non-fermented and 56-d-fermented TMR during air exposure (Figure 1).
The present study was designed to investigate whether the duration of peritoneal air exposure affects the POI intestinal inflammation and to determine the underlying mechanisms, including the role of oxidative stress responses.
Therefore, in the present study, D-lactate was chosen as a marker for the changes in intestinal barriers after peritoneal air exposure. The blood samples were obtained from the inferior vena cava.
This simulation has been undertaken extensively for fishes in recent years (see Davis, 2002), and controlled laboratory exposures to stressors relevant to fishing, such as air exposure and dropping of crabs (during handling on ships), have been conducted for lobsters (Brown and Caputi, 1983; DiNardo et al., 2002; Harris and Ulmestrand, 2004) and crabs (Zhou and Shirley, 1995; Grant 2003).
Fish were submitted to the conditions: T1: undisturbed fish (control) (3 boxes), T2: chasing and 3 minutes of air exposure (15 boxes), T3: chasing and 5 minutes of air exposure (15 boxes).
Urine nitrites can be falsely elevated due to contamination, air exposure, or phenazopyridine, and can be falsely negative due to elevated specific gravity, elevated urobilinogen levels, nitrate reductase-negative bacteria, PH < 6.0, and vitamin C.
But air exposure took its toll as the remains were shuttled around.
Stress responses in juvenile pacu (Piaractus mesopotamicus) submitted to repeated air exposure
But when it slows down, it becomes brown from air exposure. Plus, your uterus is self-cleaning, so when you menstruate you shed its lining.
One problem for the researchers, was sustaining the cells' life because they are vulnerable to photo-degradation after a few hours of air exposure. As a result, they encapsulated them inside a flexible gas barrier, extending their life to about 3,000 hours.
The 50 papers cover air exposure modeling and assessment, indoor air quality and exposure, the environmental fate and health effects of emerging water contaminants, exposure-dose reconstruction, biomarkers in exposure studies, chemical mixtures and exposure, health risk analysis, exposure monitoring and modeling, environmental impact and exposure, and communications and social issues.