Radiation layer temperatures

The terrperature of the hot layer in the corridor is shown in Figure 7. In the corridor, the hot gas is untenable for an upright person next to the open fire room door after about 160 seconds. After about four minutes, the radiation from the hot layer would be too high to permit a person to pass. Furthermore, in actual fact, the temperature would be higher than that calculated at the fire room door, because of the fuel which would burn in the corridor, thus providing flame temperature radiation in addition to the hot layer temperature computed here. 

The thermosphere is the thin outer layer of our atmosphere extending from the mesopause near 80 km. altitude out to the exosphere, some several thousand kin. altitude, where the mean free path is sufficiently long to allow escape of atomic hydrogen and helium and atmospheric capture of coronal gas constituents. In the lower thermosphere, heated by solar ultraviolet and x-radiation, the temperature increases rapidly with altitude, with temperatures above 400 km. varying between about 700° and 2100°K., depending on solar activity. 

In a first approximation, for the dimensions of the radiating layers with which we must work, we may consider that each element of volume radiates independently of the others, and we thus have the conditions to which the calculations of the previous section refer. For mixtures of carbon monoxide, in which the flame velocity has been studied in detail, we carried out detailed calculations of the influence of radiation on the combustion temperature. 

Calculate the heat transferred by solar radiation on the flat concrete roof of a building, 8 m by 9 m, if the surface temperature of the roof is 330 K. What would be the effect of covering the roof with a highly reflecting surface, such as polished aluminium, separated from the concrete by an efficient layer of insulation The emissivity of concrete at 330 K is 0.89, whilst the total absorptivity of solar radiation (sun temperature = 5500 K) at this temperature is 0.60. 

The physical conditions of the atmosphere in the vicinity of the Earth surface are determined by friction and by heat transfer. Friction reduces wind velocity and turbulence as one approaches the surface, so that the eddy transport rate declines. Heating of the surface by solar radiation imparts energy to the overlying air, causing an enhancement of vertical motions and eddy transport owing to convection. An increase of temperature with height in the atmosphere for a certain distance instead of the normal, adiabatic decrease is called a temperature inversion layer. Temperature... 

Here we consider the above-prepared radiation balance of a biplane system made from thin foils. Both planes (numbered 1 and 2) are lined up parallel to each other. The upper plane (2) on the upper side has reflectivity p2+, emissivity 2+ and absorption o +, and on the bottom reflectivity p2-, emis-sivity 2- and absorption 2- the transmissivity is T2. Analogous to this, the corresponding variables of the lower plane (1) are given by pu, Pi-, u, 1-, ai and Ti, where the subscript l-i- describes the characteristics of the upper layer and 1- those of the bottom of plane 1. The temperature of the upper foil is 2 and the temperature of the bottom foil is i. In the space above the second upper foil there is a diffuse black-body radiation of temperature 9 and in the space below the first foil a black-body radiation of temperature . ,. 

In defining the energy flow, only the temperatures 0j and 02 of layers 1 and 2 are still unknown. Here it can be assumed that due to the minor thickness of the membrane the temperatures of the layers are constant across the entire layer. Compensation processes take place in the adjacent air layers and are treated below. These layer temperatures are calculated from the absorbed radiation energies in the single layers, the energies registered by convection and the particular warmth of the layer per unit area. Here only the radiation fractions are processed. For layer 2, for the total radiation inflow ... 

Figure 32.10 shows the variations of (a) wind, (b) daily solar radiation, chlorophyll a [Stn. 1 (c), Stn. 2 (d), and Stn. 3 (e)], water temperature [Stn. 1 (f), Stn. 2 (g), and Stn. 3 (h)], and salinity [Stn. 1 (i), Stn. 2 (j), and Stn. 3 (k)]. Station 1 is located at the inner most part of east side of the bay, Stn. 2 at the center part of east side of the bay, and Stn. 3 at the west part of the inner part of Tokyo Bay (see Fig. 32.2). Chlorophyll a content varied rapidly between 0 and 100/xg/l. Chlorophyll a increased during the five periods marked by A-E in Fig. 32.10(c)-32.10(e). The increase of chlorophyll a was observed almost simultaneously at the three stations, except at Stn. 3 during A and E. So, the general variation of phytoplankton is almost the same inside the bay. The maximum chlorophyll a occurred in period B at the three stations. For these five periods, when the north wind began to blow, the blooms stopped rapidly. This is because a strong north wind caused outward transport from the inner bay and upwelling at the east side of the bay, resulting in advection and dispersion of ph doplankton in the water column. For example, when a north wind blew, the surface water temperature at Stn. 1 fell rapidly as shown in Fig. 32.10(f) (on April 20, 25, 30, May 15, June 9, and 19). In contrast, the bottom water temperature at Stn. 2 rose sharply as shown in Fig. 32.10(g) (on April 25, 30, May 15, June 9, and 19). On the other hand, the south wind caused the contrary phenomena, and the bottom layer temperature rose sharply at Stn. 1 (on May 5, 20, 28, June 3, 11, and 24). In contrast, the surface temperature fell at Stn. 2. These responses to the wind seemed to have occurred because the two stations are located on the east and west sides of the inner bay while downwelling occurs at one station, upwelling occurs at the other. These responses are particularly clear at Stn. 2, since it is located at the innermost part...

In stratified water storage the warm water from the collector enters near the top of the tank the fluid led back to the collector is drawn from the bottom of the tank by a pump. Thus in the upper layers of the tank there is always warm water, and the lower layers contain cold water. The advantage of this method is that the collector receives cold water as long as cold layer exists near the bottom of the tank [56,106,107] accordingly, the collector works with approximately constant efficiency. The thickness of the transient temperature zone is determined by the time boundaries of the temperature changes of the water coming from the collector. In operation periods of reduced radiation, the temperature of the water from the collector is lower than that of the temperature in the top layer. This water descends and causes mixing in the tank. 

In this accident, the steam was isolated from the reactor containing the unfinished batch and the agitator was switched ofiF. The steam used to heat the reactor was the exhaust from a steam turbine at 190 C but which rose to about 300°C when the plant was shutdown. The reactor walls below the liquid level fell to the same temperature as the liquid, around 160°C. The reactor walls above the liquid level remained hotter because of the high-temperature steam at shutdown (but now isolated). Heat then passed by conduction and radiation from the walls to the top layer of the stagnant liquid, which became hot enough for a runaway reaction to start (see Fig. 9.3). Once started in the upper layer, the reaction then propagated throughout the reactor. If the steam had been cooler, say, 180 C, the runaway could not have occurred. ... 

Thermal turbulence is turbulence induced by the stability of the atmosphere. When the Earth s surface is heated by the sun s radiation, the lower layer of the atmosphere tends to rise and thermal turbulence becomes greater, especially under conditions of light wind. On clear nights with wind, heat is radiated from the Earth s surface, resulting in the cooling of the ground and the air adjacent to it. This results in extreme stabihty of the atmosphere near the Earth s surface. Under these conditions, turbulence is at a minimum. Attempts to relate different measures of turbulence of the wind (or stability of the atmosphere) to atmospheric diffusion have been made for some time. The measurement of atmospheric stabihty by temperature-difference measurements on a tower is frequently ntihzed as an indirect measure of turbulence, particularly when climatological estimates of turbulence are desired. 

Polymerization in aqueous solution of acrylamide can also be fulfilled in thin layers (up to 20 mm) applied on a steel plate or a traveling steel band. Polymerization is initiated by persulfates, redox system, UV or y radiation. Polymerization proceeds in isothermal conditions as the heat of polymerization is dissipated in the environment and, additionally, absorbed by the steel carrier. Nonadhesion of the polymer to the carrier is ensured by the addition of glycerol to isopropyl alcohol or by precoating the steel band with a film based on fluor-containing polymers. This makes polymerization possible at a high concentration of the monomer (20-45%) and in a wider process temperature range. This film of polyacrylamide is removed from the band, crushed, dried, and packed. 

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