Cooling phenomenon

In a cooling tower s operation, sensible heat also plays a role. When warm water contacts cooler air, the air cools the water and its temperature rises as it gains the sensible heat of the water. Roughly 25%,of the sensible heat transfer takes place within the tower, with the balance of the cooling phenomenon achieved from the evaporative effect of the latent heat of vaporization. In simple terms, a cooling tower is a device that transfers quantities of heat from one mass to another. As we will see in later chapters, a cooling tower is simply an air-mass heat exchanger. 

MICHEAU - It is now very well known that the overhelming majority of photochemical spatial patterns are in fact due to a coupling of a linear photochemical reaction with a convection process coming from an evaporative cooling phenomenon. The patterns do not appear if convection is not allowed concerning now the new photochemical bistable system this system must be used in a CSTR under UV irradiation (360 nm) so, I don t see any special condition where spatial patterns could be experimentally observed. 

Although samples of rubber and of steel can be regarded as Hookean (within the limit of small deformations), they do not undergo the same phenomena during deformation upon stretching, a steel sample experiences a cooling phenomenon while that of rubber a heating one. 

Cool Flames. An intriguing phenomenon known as "cool" flames or oscillations appears to be intimately associated with NTC relationships. A cool flame occurs in static systems at certain compositions of hydrocarbon and oxygen mixtures over certain ranges of temperature and pressure. After an induction period of a few minutes, a pale blue flame may propagate slowly outward from the center of the reaction vessel. Depending on conditions, several such flames may be seen in succession. As many as five have been reported for propane (75) and for methyl ethyl ketone (76) six have been reported for butane (77). As many as 10 cool flames have been reported for some alkanes (60). The relationships of cool flames to other VPO domains are depicted in Figure 6. 

The reported characteristics of methane oxidation at high pressures are interesting. As expected,the reaction can be conducted at lower temperatures eg, 262°C at 334 MPa (3300 atm) (100). However, the cool flame phenomenon is observed even under these conditions. At high pressures. 

Glass-Transition Temperature. When a typical Hquid is cooled, its volume decreases slowly until the melting point, T, where the volume decreases abmpdy as the Hquid is transformed into a crystalline soHd. This phenomenon is illustrated by the line ABCD in Eigure 3. If a glass forming Hquid is cooled below (B in Eig. 3) without the occurrence of crystallization, it is considered to be a supercooled Hquid until the glass-transition temperature, T, is reached. At temperatures below T, the material is a soHd. 

The aqueous micellai solutions of some surfactants exhibit the cloud point, or turbidity, phenomenon when the solution is heated or cooled above or below a certain temperature. Then the phase sepai ation into two isotropic liquid phases occurs a concentrated phase containing most of the surfactant and an aqueous phase containing a surfactant concentration close to the critical micellar concentration. The anionic surfactant solutions show this phenomenon in acid media without any temperature modifications. The aim of the present work is to explore the analytical possibilities of acid-induced cloud point extraction in the extraction and preconcentration of polycyclic ai omatic hydrocai bons (PAHs) from water solutions. The combination of extraction, preconcentration and luminescence detection of PAHs in one step under their trace determination in objects mentioned allows to exclude the use of lai ge volumes of expensive, high-purity and toxic organic solvents and replace the known time and solvent consuming procedures by more simple and convenient methods. 

With tube side condensation, coefficients are generally lower than for comparable shell side condensers. This phenomenon is attributed to (1) lower coolant velocities outside the tubes than are possible with tube side cooling, and (2) increased film thicknesses, namely, film resistance inside the tubes. 

Noble gas hydrates are formed similarly when water is frozen under a high pressure of gas (p. 626). They have the ideal composition, [Gg(H20)46], and again are formed by Ar, Kr and Xe but not by He or Ne. A comparable phenomenon occurs when synthetic zeolites (molecular sieves) are cooled under a high pressure of gas, and Ar and Kr have been encapsulated in this way (p. 358). Samples containing up to 20% by weight of Ar have been obtained. 

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