Cooling objectives

Condensation occurs when air temperatures cool. The cooling occurs in one of two ways. Either the air vapor cools as it rises and expands or as it comes into contact with a cool object such as a cold landmass or an ice-covered area. Air rises for several reasons. It can be forced up as it encounters a cooler, denser body of air, or when it meets mountains or other raised land masses. It can rise as it meets a very warm surface, like a desert, and become more buoyant than the surrounding air. Air also can be forced to rise by storms—during tornadoes particles of air circling to the center of a cyclone collide and are forced up. When the water vapor collides with a cold object, it can become fog, dew, or frost as it condenses. The vapor cools as it rises into the atmosphere and condenses to form clouds and, sometimes, rain. 

Most of us associate temperature (7) with the concepts of hot and cold. More accurately, however, temperature is the property of an object that determines the direction of heat flow. Heat flows naturally from a warm object to a cool object, from higher temperature to lower temperature. Heat is a form of energy, and because energy changes in chemical systems have important consequences, chemists are interested in temperature changes that occur during chemical transformations. 

Due to the presence of the Belt the rate of SN around us (say in few hundred parsecs) during the last several tens of million years is higher, than it is in an average place at a solar distance from the galactic center. Because of that there should be a local overabundance of young NSs which can appear as hot cooling objects, as gamma-ray sources etc. 

We will consider the two semi-infinite bodies shown in Fig. 2.24, which have different, but constant, initial temperatures d01 and d02- Their material properties Ax, a1 and A2, a2 are also different. At time t = 0 both bodies are brought into (thermal) contact with each other along the plane indicated by x = 0. After a very short period of time an average temperature is reached along the plane. Heat flows from body 1 with the higher initial temperature to body 2 which has a lower temperature. The transient conduction process described here serves as a model for the description of short-time contact between two (finite) bodies at different temperatures. Examples of this include the touching of different objects with a hand or foot and the short-time interaction of a heated metal body with a cooled object in reforming processes. 

When the Earth was in its early stages of accretion, it was presumably a cool object. In the final stages, accretional energy was appreciable and must have heated the upper regions of the Earth s interior. When the Earth approached its present mass, projectiles would impact at a minimum velocity of... 

Conduction cooling This is an indirect method by which the object is cooled through a conductor connecting the cooled object with the cooling medium. It is difficult to utilize the entire capacity of the cooling medium because of the thermal resistance of the conductor. Moreover, it is difficult to attain an equilibrium temperature when the cooled object is subjected to a rising temperature. 

Objects near room temperature emit most of their radiation in the IR band. Even relatively cool objects, however, emit some IR radiation hot objects, such as incandescent filaments, emit strong IR radiation. 

LIRTS would have wide application for studies of cool objects including planetary atmospheres, early and late type stars, the interstellar medium and external galaxies. Recent and unexpected discoveries have shown that observations in this spectral region are vital to our understanding of many important phenomena, including that of star formation, which occur in visually obscured regions. 

Figure 3.26 shows an analogous scheme for moving heat from a cool fluid to a warm fluid. The heat drains spontaneously from the cool object to a colder object the object is warmed and then the heat drains to the warm fluid. 

The inverse of this example is vapor deposition. If we place a cool object in a space in which the vapor s pressure is higher than the vapor pressure of pure solid at the temperature of the cool object, then the vapor will condense on the cool object. Many variants of this process are used in the production of computer chips. (Some are simple physical deposition as described here others are... 

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