condensation

Dictionary: con·den·sa·tion   (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.

The notion that dreams provide an avenue for the expression of normally repressed desires while simultaneously disguising and censoring our real urges was systematically formulated by Sigmund Freud, the father of psychoanalysis. In Freud's view, the purpose of dreams is to allow us to satisfy in fantasies the instinctual urges that society judges to be unacceptable in some way, such as the urge to seduce or to kill. If, however, we were to dream about an actual seduction or an actual assault, the emotions evoked by the dream would awaken us. So that our sleep is not continually disturbed by such dreams, the mind modifies and disguises their content so that strong emotions are not evoked. Freud referred to the process of censoring and transforming dream contents into less disturbing images as the dreamwork, and explicitly identified five processes through which dreams are censored: displacement, condensation, symbolization, projection, and secondary revision.

Condensation, as the word implies, is a process that disguises a particular thought, urge, or emotion by contracting it into a brief dream event or image, the deeper meaning of which is not readily evident. Condensation also refers to the tendency of the dreamwork to bring together two or more different experiences or concerns into a single dream narrative or image. In Freud's words,

From every element in a dream's content associative threads branch out in two or more directions; every situation in a dream seems to be put together out of two or more impressions or experiences.

The overlap of two or more distinct sets of associations in one dream situation effectively disguises the true meaning of the dream.

For other uses, see Condensation (disambiguation).

It has been suggested that Condensation (aerosol dynamics) be merged into this article or section. (Discuss)

Water vapor condenses into liquid after making contact with the very top surface of a cold bottle.

Condensation on a window during a rain shower.

Condensation is the change of the physical state of aggregation (or simply state) of matter from gaseous phase into liquid phase.^[1] When the transition happens from the gaseous phase into the solid phase directly, bypassing the liquid phase, the change is called deposition.

Condensation commonly occurs when a vapor is cooled to its dew point, but the dew point can also be reached through compression. The condensed vapor is called a condensate, the laboratory or the industrial equipment used for condensation is called a condenser.

The science of studying the thermodynamic properties of moist air and the interrelationships between these in order to analyze, and predict properties by changing in the conditions of moist air is called psychrometry. The interrelationship can be graphically represented, and prediction carried out graphically by the psychrometric chart. Most people think the water is condensation, but condensation is only the process of change.

Water vapor that naturally condenses on cold surfaces into liquid water is called dew. Water vapor will only condense onto another surface when the temperature of that surface is cooler than the temperature of the water vapor. The water molecule brings a parcel of heat with it. In order to have condensed, the molecule transfers its kinetic energy to the atmosphere. When water vapor condenses into liquid water, the hydrogen bonds form again and release latent heat, which increases the sensible heat and causes the air temperature to rise. Sensible heat is removed from the air and the temperature drops when evaporation is occurring and latent heat is converted to sensible heat and the temperature rises when condensation occurs.

Contents 1 Applications of condensation 2 See also 3 Notes 4 References 5 External links

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: Many structures that are made solely for the purpose of collecting water from condensation, such as air wells and fog fences. Such systems can often be used to retain soil moisture in areas where active desertification is occurring—so much so that some organizations educate people living in affected areas about water condensers to help them deal effectively with the situation.^[2]

See also

• Air well (condenser)
• Kelvin equation
• Retrograde condensation
• Phase diagram
• Phase transition
• Condenser (heat transfer)
• Surface condenser
• Bose–Einstein condensate

Notes

1. ^ International Union of Pure and Applied Chemistry. "condensation in atmospheric chemistry". Compendium of Chemical Terminology Internet edition.
2. ^ FogQuest - Fog Collection / Water Harvesting Projects - Welcome

References

• "Condensation principles (Picture)". http://www.ces.purdue.edu/pork/images/jones/condense.jpg. 

External links

• Guide to condensation in buildings and how to overcome

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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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