Equivalent solar temperature

The equivalent solar temperature for thermal radiation is therefore about 5800 K (10,000°R). 

It is quite apparent from Fig. 8-63 that solar radiation which arrives at the surface of the earth does not behave like the radiation from an ideal gray body, while outside the atmosphere the distribution of energy follows more of an ideal pattern. To determine an equivalent blackbody temperature for the solar radiation, we might employ the wavelength at which the maximum in the spectrum occurs (about 0.5 /im, according to Fig. 8-63) and Wien s displacement law [Eq. (8-13)]. This estimate gives... 

We present here the results of abundance measurements of iron, calcium and nickel in four open clusters, from UVES spectra of solar type stars. A code developed by one of the authors (Francois) performs line recognization, equivalent width measurements and finally obtains the abundances by means of OSMARCS LTE model atmosphere [4]. Temperature, gravity and microturbulence velocity have to be input to the program. This is made in an automatic way for a grid of values chosen on photometric basis. Those that best reproduce excitation and ionization equilibria are selected and used, namely when no significant trend of the computed abundances is seen, neither versus the excitation potential of the line nor versus its equivalent width, and for which the abundances obtained with lines of different ionization stages of the same specie give equal results within the errors. This check is made with iron lines, we have in fact at least thirty Fe I lines in each star, and six Fell lines. 

Since the earth has temperature, it emits radiant energy called thermal radiation or planetary infrared radiation. Measurements by satellites show an average radiant emission from the earth of about 240 watts per square meter. This is equivalent to the radiation that a black body would emit if its temperature is at -19°C (-3°F). This is also the same energy rate as the solar constant averaged over the earth s surface minus the 30% reflected radiation. This shows that the amount of radiation emitted by the earth is closely balanced by the amount of solar energy absorbed and since the earth is in this state of balance, its temperature will change relatively slowly from year to year. 

Fig. 3.3. Theoretical Hertzsprung-Russell diagram. The right-hand scale shows in absolute bolometric magnitude what the left-hand scale expresses as the logarithm of the intrinsic luminosity in units of the solar intrinsic luminosity (Lq = 4 x 10 erg s ). On the horizontal axis, the logarithm of the effective temperature, i.e. the temperature of the equivalent blackbody, is put into correspondence with the spectral type of the star, as determined by the observer. This temperature-luminosity diagram shows the lifelines of the stars as strands combed out like hair across the graph. With a suitable interpretation, i.e. viewed through the explanatory machinery of nuclear physics, it opens the way to an understanding of stellar evolution and its twin science of nucleosynthesis. (Courtesy of Andre Maeder and co-workers.)...

The sun s total radiation output is approximately equivalent to that of a blackbody at 10,350°R (5750 K). However, its maximum intensity occurs at a wavelength that corresponds to a temperature of 11,070°R (6150 K) as given hy Wien s displacement law. A figure plotting solar irradiance versus spectral distribution of solar energy is given in Fig. 9. See also Solar Energy. 

An allotrope of oxygen, ozone, O, (8), forms in the stratosphere by the effect of solar radiation on 02 molecules. Its total abundance in the atmosphere is equivalent to a layer that, at normal temperature and pressure, would cover the Earth to a thickness of only 3 mm. Ozone can be made in the laboratory by passing an electric discharge through oxygen. It is a blue gas that condenses at — 112°C to an explosive blue liquid that... 

Table V. Equivalent Temperature of Rayleigh Scattered Solar Radiation for Clear Sky Conditions ...

Such an inductor generates a temperature field of almost square symmetry. The main slit in the inductor, which forms the current loop, however, is not completely equivalent to the other three slits as seen in Fig. 3.9b. Furthermore, the surface tension surrounds the corners by minimizing the melt surface, which is not desired because the goal are quadratic wafers directly cut from the crystals. Additionally, on the straight sides, where the horizontal curvature is almost zero, growth instabilities can occur. Regarding the application for the solar industry, which would save material loss and the costs of cutting the round crystal into a square one, it is essential to get a stable... 

A better description of the solar spectrum is obtained by adopting an equivalent temperature which varies with frequency. Such an equivalent temperature corresponds to the temperature of an effective emission layer in the solar atmosphere at the frequency. A complete description has to account for the solar emission lines in the visible, near ultraviolet, and far ultraviolet regions (see below). 

Carrying out distillation using a vacuum (low pressure) allows use of lower temperatures and attains higher alcohol concentrations. For instance, at 42 mm Hg pressure (about 6 percent of atmospheric pressure (Normal atmospheric pressure is 760 mm Hg (millimeters of mercury column), equivalent to 30 inches of Hg or 14.7 psi. Thus, 6 percent of 14.7 psi is approximately 0.88 psi.), the temperature at the bottom of the column need only be about 35° C (95° F) and the top about 20° C (68° F). This makes it hard to condense the vapor, since there is a smaller temperature difference between the vapor and the coolant (whether air or water). But this pressure may be advantageous if heat is supplied at only 35° C Here, waste heat from other machinery or solar heat might be exploited. 

Water is abundant on our planet, distinguishing Earth from all other planets in the solar system. More than 97% of Earth s water is in the oceans, with 2.1% in the polar ice caps and 0.6% in aquifers. The atmosphere contains only about one part in a hundred thousand (0.001%) of Earth s available water. However, the transport and phase distribution of this relatively small amount of water (estimated total liquid equivalent volume of 13,000 km3) are some of the most important features of Earth s climate. The existence of varying pressures and temperatures in the atmosphere and at the Earth s surface causes water to constantly transfer among its gaseous, liquid, and solid states. Clouds, fogs, rain, dew, and wet aerosol particles represent different forms of that water. Aqueous atmospheric particles play a major role in atmospheric chemistry, atmospheric radiation, and atmospheric dynamics. 

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