Dictionary:

condensation

  (kŏn'dĕn-sā'shən, -dən-)

1. The act of condensing.
2. The state of being condensed.
3. A condensate.
4. An abridgement or shortening of something, especially of a written work or speech.
5. Physics.
   1. The process by which a gas or vapor changes to a liquid.
   2. The liquid so formed.
6. Chemistry. A chemical reaction in which water or another simple substance is released by the combination of two or more molecules.
7. Psychology. The process by which a single symbol or word is associated with the emotional content of several, not necessarily related, ideas, feelings, memories, or impulses, especially as expressed in dreams.

A phase-change process in which vapor converts into liquid when the temperature of the vapor is reduced below the saturation temperature corresponding to the pressure in the vapor. For a pure vapor this pressure is the total pressure, whereas in a mixture of a vapor and a noncondensable gas it is the partial pressure of the vapor. Sustaining the process of condensation on a cold surface in a steady state requires cooling of the surface by external means. Condensation is an efficient heat transfer process and is utilized in various industrial applications. Condensation of vapor on a cold surface can be classified as filmwise or dropwise. Direct-contact condensation refers to condensation of vapor (bubbles or a vapor stream) in a liquid or condensation on liquid droplets entrained in the vapor. If vapor temperature falls below its saturation temperature, condensation can occur in the bulk vapor. This phenomenon is called homogeneous condensation (formation of fog) and is facilitated by foreign particles such as dust. See also Gas; Heat transfer.

In film condensation, a thin film of liquid forms upon condensation of vapor on a cold surface that is well wetted by the condensate. The liquid film flows downward as a result of gravity.

In dropwise condensation, on surfaces that are not well wetted, vapor may condense in the form of droplets (see illustration). The droplets form on imperfections such as cavities, dents, and cracks on the surface. The droplets of 10–100 μm diameter contribute most to the heat transfer rate. As a droplet grows to a size that can roll down the surface because of gravity, it wipes the surface of the droplets in its path. In the wake behind the large droplet, numerous smaller droplets form and the process repeats. The heat transfer coefficients with dropwise condensation can be one to two orders of magnitude greater then that for film condensation.

Steam at atmospheric pressure condensing on a vertical copper surface. Film condensation is visible on the right side, and dropwise condensation in the presence of a promoter is visible on the left side. The horizontal tube is a thermocouple. (J. F. Welch and J. W. Westwater, Department of Chemical Engineering, University of Illinois, Urbana)

Direct-condensation involves condensation of vapor bubbles in a host liquid and condensation on droplets entrained in vapor. Both are also very efficient heat transfer processes, especially when the vapor-liquid interface oscillates.

noun

A short summary or version prepared by cutting down a larger work: abridgment, abstract, brief, epitome, synopsis. See words.

Definition: abridgment
Antonyms: unabridgment

n

Definition: water buildup
Antonyms: dryness

A commonly used term for the insertion and compression or compaction of dental materials into a prepared cavity. Compaction is a more accurate term than condensation. See also compaction.

The change of a vapour or gas into liquid form. This change of state is accompanied by the release of latent heat, which alters the adiabatic temperature change in rising air. Condensation in meteorology can be caused by: the cooling of a constant volume of air to dew point, the expansion of a parcel of air without heat input, the evaporation of extra moisture into the air, the fall in the moisture-holding capacity of the air due to changes in both volume and temperature, and contact with a colder material or air mass.

The likelihood of water vapour condensing will depend on the saturation vapour pressures of water and ice at any given temperature, and/or the presence of condensation nuclei, since water vapour can be cooled to well below 0 °C before condensation occurs. see condensation nuclei, Bergeron-Findeisen theory.

For more information on condensation, visit Britannica.com.

1. In a refrigeration system, the process of changing the refrigerant into liquid by the extraction of heat.
2. See surface condensation.

Condensation, along with displacement, is an essential process in dream work and more generally in primary-process thinking. We tend to view it as a way of attributing, to a person or representative object, characteristics and properties that, from the point of view of latent thoughts, belong to other persons or objects. In reality, if we go by Freud's text in The Interpretation of Dreams (1900a), condensation, like displacement, does not proceed directly by modifying the content of a representation. All dreams are made up of latent dream thoughts, each of which corresponds to one or several chains of associations, with each link being initially charged with a psychic intensity. Dream work consists in changing the location of these fragmentary intensities without either increasing or reducing their global value.

In displacement, one assigns to link A in a chain of associations the intensity initially associated with link B. Condensation, in contrast, operates by bringing intensities together. When two chains of association intersect, it assigns to the common link the sum of the intensities of the two intersecting chains. This nevertheless indirectly alters the representation because, in the manifest content of the dream, a link will not figure if it does not retain an intensity. By displacing the intensities of several chains to their common link, condensation makes it possible to represent all of the chains by a single link. Hence, there is an economy of means that contributes to censorship. As a result, when one link takes the place of several chains, this makes it more difficult to read through to the wish corresponding to those chains.

Condensation thus has an indirect effect on the figural content of representations. It does not create chimeras that bring together in one element the attributes of others. Nor does it engage in metonymy, in which one of the links represents one or several chains of association. It is a process that operates by displacing intensity, but when the intensity of several chains is brought to bear on their common link, condensation seeks to represent them all.

When explaining the effect of condensation, Freud used the metaphor of italics. A representative link whose intensity has been reinforced by condensation has a status comparable to that of a word in italics in a text. This metaphor calls for two remarks. First, the intensity added to a fragment of a representation through condensation makes it possible, like italics, to stress the importance of the representation. This added intensity indicates at the manifest level that the representation stands for the different latent chains intersecting at the link. Second, typographical emphasis warps the texture of a text and invites us to look for links other than those offered by successive statements. Typographical emphasis is an invitation to abandon linearity and search for the dreamer's associations.

The notion of intensity is complex. The term indicates the psychic interest of a particular idea. But we may well ask whether this interest should not be extended to the affect associated with each chain of associations or the instinct that determines each association.

Although Freud studied condensation particularly in relation to dreams, especially in The Interpretation of Dreams, he also describes the effect of this process in other manifestations of primary-process thinking, such as jokes, forgetting names, slips of the tongue, and symptoms. In these latter domains, however, it is sometimes quite difficult to distinguish between condensation and overdetermination. In both cases, as the result of a transformation, a representation substitutes for more elaborate thought content. Both processes seem to proceed by increasing intensity, that is, by economic modification, and this results in the reorganization of the thought content. But whereas condensation can be viewed as a sum of intensities relative to forces acting in the same direction, overdetermination appears more as an appropriation of content by heterogeneous if not antagonistic forces. In fact, the content of an overdetermined representation acts as a fulcrum for opposing logics and conflicting systems (such as the preconscious and the unconscious). A thought content (or representation) resulting from the interaction of forces pushing for the fulfillment of an unconscious wish and forces opposing it (the censor) is a good example of overdetermination but not of condensation, since the censor is not part of the latent dream thoughts. However, as soon as the signifying element begins to represent conflict (as in the case of a symptom), the difference between condensation and overdetermination is more difficult to establish.

Bibliography

Freud, Sigmund. (1900a). The interpretation of dreams. SE, 4: 1-338; 5: 339-625.

——. (1905c). Jokes and their relation to the unconscious. SE, 8: 1-236.

——. (1916-1917a [1915-17]). Introductory lectures on psycho-analysis. SE, 15: 9-239; 16: 243-463.

—LAURENT DANON-BOILEAU

1. the act of rendering, or the process of becoming, more compact.
2. the process of passing from a gaseous to a liquid or solid phase. In animal housing this is a matter of great importance because of the need for a dry environment as a prevention against the spread of infection, especially those spread by inhalation.

Water condenses into visible droplets after evaporating from a cup of hot tea

Condensation is the change in matter of a substance to a denser phase, such as a gas (or vapor) to a liquid.^[1] Condensation commonly occurs when a vapor is cooled to a liquid, but can also occur if a vapor is compressed (i.e., pressure on it increased) into a liquid, or undergoes a combination of cooling and compression. Liquid which has been condensed from a vapor is called condensate. A device or unit used to condense vapors into liquid is called a condenser. Condensers are used in heat exchangers which have various designs, and come in many sizes ranging from rather small (hand-held) to very large.

The water seen on the outside of a cold glass on a hot day is an example of condensation.

Condensation of water in nature

Dew on a spider web

Water vapor from air which naturally condenses on cold surfaces into liquid water is called dew. Water vapor will only condense onto another surface when that surface is cooler than the temperature of the water vapor, or when the water vapor equilibrium in air, i. e. saturation humidity, has been exceeded. When water vapor condenses onto a surface, a net warming occurs on that surface.

Condensation on a cold bottle of water.

The water molecule brings a parcel of heat with it. In turn, the temperature of the atmosphere drops very slightly.

In the atmosphere, condensation of water vapor is what produces clouds. The dew point of an air parcel is the temperature to which it must cool before condensation in the air begins to form.

Also, a net condensation of water vapor occurs on surfaces when the temperature of the surface is at or below the dew point temperature of the atmosphere. Deposition is a type of condensation. Deposition, the direct formation of ice from water vapor, is a type of condensation. Frost and snow are examples of deposition.

Condensation in buildings

Condensation is the most common form of dampness encountered in buildings. In buildings the internal air can have a high level of relative humidity due to the activity of the occupants (e.g. cooking, drying clothes, breathing etc...). When this air comes into contact with cold surfaces such as windows and cold walls it can condense, causing dampness.^[2] the change from water vapor to liquid water (dew,fog,clouds)

Applications of condensation

Condensation is a crucial component of distillation, an important application in laboratory and industrial chemistry application.

Because condensation is a naturally occurring phenomenon, it can often be used to generate water in large quantities for human use. In fact, there are many structures that are made solely for the purpose of collecting water from condensation, such as fog fences, air wells and dew ponds. Such systems can often be used to retain soil moisture in areas where active desertification is occurring. In fact, certain organizations use education about water condensers in efforts to effectively aid such areas.^[3]

References

• Condensation principles (Picture).
• Condensation & Evaporation Experiment (Video).

1. ^ International Union of Pure and Applied Chemistry. "condensation in atmospheric chemistry". Compendium of Chemical Terminology Internet edition.
2. ^ http://www.buildingpreservation.com/Condensation.htm Building Preservation (Condensation - the basics)
3. ^ http://www.fogquest.org/

See also

• Kelvin equation
• Phase diagram
• Phase transition

External links

• Condensation Myths and Facts

From	To
	Solid	Liquid	Gas	Plasma
Solid	Solid-Solid Transformation	Melting	Sublimation	-
Liquid	Freezing	N/A	Boiling/Evaporation	-
Gas	Deposition	Condensation	N/A	Ionization
Plasma	-	-	Recombination/Deionization	N/A

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - fortætning, nedslag, forkortelse, sammentrængning

Nederlands (Dutch)
condensatie, verkorte versie

Français (French)
n. - condensation, buée, (Chim) condensation, version condensée

Deutsch (German)
n. - Kondensation, Verflüssigung, Kurzfassung

Ελληνική (Greek)
n. - συμπύκνωση, υγροποίηση, εξίδρωση

Italiano (Italian)
condensazione

Português (Portuguese)
n. - condensação (f)

Русский (Russian)
конденсация

Español (Spanish)
n. - condensación

Svenska (Swedish)
n. - kondensering, förtätning, imma, hopgyttring, sammanträngning, nedskärning

中文（简体） (Chinese (Simplified))
压缩, 液化, 凝缩

中文（繁體） (Chinese (Traditional))
n. - 壓縮, 液化, 凝縮

한국어 (Korean)
n. - 응축, 액화, 요약

日本語 (Japanese)
n. - 凝縮, 凝結, 濃縮, 凝縮されたもの, 水滴, 簡約, 要約

العربيه (Arabic)
‏(الاسم) تكثف, رطوبه, تلخيص‏

עברית (Hebrew)
n. - ‮עיבוי, טיפות, ריכוז, קיצור, אדים‬

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