Earth temperature

Brett R., Huebner J. S., and Sato M. (1977) Measured oxygen fugacities of the Angra dos Reis achondrite as a function of temperature. Earth Planet. Sci. Lett. 35, 363-368. 

Boehler R. (1992) Melting of the Fe-FeO and the Fe-FeS systems at high pressure constraints on core temperatures. Earth Planet. Sci. Lett. Ill, 217—227. 

Ohtani E. and Ringwood A. E. (1984) Composition of the core I. Solubility of oxygen in molten iron at high temperatures. Earth Planet. Sci. Lett. 71, 85-93. 

Bierens de Haan, S., 1991, A review ofthe rate ofpyrite oxidation in aqueous systems at low temperature Earth-Science Reviews, v. 31, no. 1, p. 1-10. 

Schouten, S., Hopmans, E.C., SchefuB, E. and Sinninghe Damste, J.S., 2002. Distributional variations in marine crenarchaeotal lipids A new tool for reconstructing ancient sea water temperatures Earth Planet. Sci. Lett., 204 265-274. 

Cooling wine to 0°C, followed by low-temperature earth filtration, reduces the risk of turbidity by partially eliminating proteins. 

CO2 acts as a greenhouse gas to affect Earth s surface temperature. Earth absorbs sunlight and then emits infrared radiation. The balance between sunlight absorbed and radiation sent back to space determines the surface temperature. A greenhouse gas absorbs infrared radiation and reradiates some of it back to the ground. By intercepting some of Earth s radiation, CO2 keeps our planet warmer than it would otherwise be. 

Yearly temperature differences from the 120-year average temperature. Earth s average temperature has increased by about 0.6 °C since 1880. Source NASA GISS Surface Temperature Analysis)... 

Atmospheric corrosion results from a metal s ambient-temperature reaction, with the earth s atmosphere as the corrosive environment. Atmospheric corrosion is electrochemical in nature, but differs from corrosion in aqueous solutions in that the electrochemical reactions occur under very thin layers of electrolyte on the metal surface. This influences the amount of oxygen present on the metal surface, since diffusion of oxygen from the atmosphere/electrolyte solution interface to the solution/metal interface is rapid. Atmospheric corrosion rates of metals are strongly influenced by moisture, temperature and presence of contaminants (e.g., NaCl, SO2,. ..). Hence, significantly different resistances to atmospheric corrosion are observed depending on the geographical location, whether mral, urban or marine. 

Ozone s presence in the atmosphere (amounting to the equivalent of a layer 3 mm thick under ordinary pressures and temperatures) helps prevent harmful ultraviolet rays of the sun from reaching the earth s surface. Pollutants in the atmosphere may have a detrimental effect on this ozone layer. Ozone is toxic and exposure should not exceed 0.2 mg/m (8-hour time-weighted average - 40-hour work week). Undiluted ozone has a bluish color. Liquid ozone is bluish black and solid ozone is violet-black. 

Cerium is an iron-gray lustrous metal. It is malleable, and oxidizes very readily at room temperature, especially in moist air. Except for europium, cerium is the most reactive of the rare-earth metals. It decomposes slowly in cold water and rapidly in hot water. 

The metal is a source of nuclear power. There is probably more energy available for use from thorium in the minerals of the earth s crust than from both uranium and fossil fuels. Any sizable demand from thorium as a nuclear fuel is still several years in the future. Work has been done in developing thorium cycle converter-reactor systems. Several prototypes, including the HTGR (high-temperature gas-cooled reactor) and MSRE (molten salt converter reactor experiment), have operated. While the HTGR reactors are efficient, they are not expected to become important commercially for many years because of certain operating difficulties. 

As with other related rare-earth metals, gadolinium is silvery white, has a metallic luster, and is malleable and ductile. At room temperature, gadolinium crystallizes in the hexagonal, close-packed alpha form. Upon heating to 1235oG, alpha gadolinium transforms into the beta form, which has a body-centered cubic structure. 

Pure holmium has a metallic to bright silver luster. It is relatively soft and malleable, and is stable in dry air at room temperature, but rapidly oxidizes in moist air and at elevated temperatures. The metal has unusual magnetic properties. Few uses have yet been found for the element. The element, as with other rare earths, seems to have a low acute toxic rating. 

Uranium can be prepared by reducing uranium halides with alkali or alkaline earth metals or by reducing uranium oxides by calcium, aluminum, or carbon at high temperatures. The metal can also be produced by electrolysis of KUF5 or UF4, dissolved in a molten mixture of CaCl2 and NaCl. High-purity uranium can be prepared by the thermal decomposition of uranium halides on a hot filament. 

Following the movement of airborne pollutants requires a natural or artificial tracer (a species specific to the source of the airborne pollutants) that can be experimentally measured at sites distant from the source. Limitations placed on the tracer, therefore, governed the design of the experimental procedure. These limitations included cost, the need to detect small quantities of the tracer, and the absence of the tracer from other natural sources. In addition, aerosols are emitted from high-temperature combustion sources that produce an abundance of very reactive species. The tracer, therefore, had to be both thermally and chemically stable. On the basis of these criteria, rare earth isotopes, such as those of Nd, were selected as tracers. The choice of tracer, in turn, dictated the analytical method (thermal ionization mass spectrometry, or TIMS) for measuring the isotopic abundances of... 

At the sorts of temperatures that exist normally on earth, all matter is made up from about 90 elements. Most of these elements are familiar, such as solid iron, liquid mercury, and gaseous helium. 

When the actual temperature-decline-with-altitude is greater than 9.8°C/1000 m, the atmosphere is unstable, the Cj s become larger, and the concentrations of poUutants lower. As the lapse rate becomes smaUer, the dispersive capacity of the atmosphere declines and reaches a minimum when the lapse rate becomes positive. At that point, a temperature inversion exists. Temperature inversions form every evening in most places. However, these inversions are usuaUy destroyed the next morning as the sun heats the earth s surface. Most episodes of high poUutant concentrations are associated with multiday inversions. 

Chemical Properties. In addition to the reactions Hsted in Table 3, boron trifluoride reacts with alkali or alkaline-earth metal oxides, as well as other inorganic alkaline materials, at 450°C to yield the trimer trifluoroboroxine [13703-95-2] (BOF), MBF, and MF (29) where M is a univalent metal ion. The trimer is stable below — 135°C but disproportionates to B2O2 and BF at higher temperatures (30). 

Properties. Lithium fluoride [7789-24-4] LiF, is a white nonhygroscopic crystaUine material that does not form a hydrate. The properties of lithium fluoride are similar to the aLkaline-earth fluorides. The solubility in water is quite low and chemical reactivity is low, similar to that of calcium fluoride and magnesium fluoride. Several chemical and physical properties of lithium fluoride are listed in Table 1. At high temperatures, lithium fluoride hydroly2es to hydrogen fluoride when heated in the presence of moisture. A bifluoride [12159-92-17, LiF HF, which forms on reaction of LiF with hydrofluoric acid, is unstable to loss of HF in the solid form. 

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