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 ?
After 4 days of air exposure at 16[degrees]C all abalones were dead and showed signs of rigor and/or putrefaction.
Dynamic changes of fermentation products that occurred in non-fermented and 56-d-fermented TMR were characterized after air exposure (Figure 2).
Evaluation of the interactive effects of air exposure duration and water temperature on the condition and survival of angled and released fish.
In the first air exposure, there was a trend of increased fish whole-body cortisol concentrations (ng [g.
Effect of air exposure on scallop behaviour, and the implications for subsequent survival in culture.
However, after monitoring the fate of individuals collected immediately after the codend was emptied (individuals that had minimal air exposure before being sorted), Macbeth et al.
This study examined how the hemolymph parameters pH, lactate, total ammonia (TA), and glucose varied with duration of air exposure at different temperatures typically encountered by the crabs during transportation.
The Danish seine is the most commonly used fishing gear for CBA, and the stressors tested in this study, forced swimming, net abrasion, and air exposure, are typical in and inherent to this type of fishing gear.
The same tests were done immediately after the 2-hr air exposure (Post), and again the next morning at approximately 0800 hours (Follow-up).
stress responses to low salinity, elevated temperature, and air exposure were size-dependant, whereas pumping rates were significantly affected by size and age (Sukhotin et al.
All REPLERE formulas are contained in airless packaging to avoid decreased potency from air exposure - and bacterial contamination - that can occur though daily use.
OBJECTIVES: To provide multifactorial indoor air exposure and health data, we conducted a population-based study of indoor air pollution and health in the United Arab Emirates (UAE).