Oxidized gaseous species

Alberti G, Carbone A, Palombari R (2001) Solid state potentiometric sensor at medium temperatures (150-300 °C) for detecting oxidable gaseous species in air. Sens Actuators B 75 125-128 Ando M, Kobayashi T, Haruta M (1996) Humidity-sensitive optical absorption of Co O film. Sens Actuators B 32 157-160... 

Thermodynamic. Thermodynamic properties of Pu metal, gaseous species, and the aqueous ions at 298 K are given in Table 8. Thermodynamic properties of elemental Pu (44), of alloys (68), and of the gaseous ions Pu", PuO", PuO" 27 PuO 2 (67) have been reviewed, as have those of aqueous ions (64), oxides (69), haUdes (70), hydrides (71), and most other compounds (65). 

There is no published work on the kinetics of simultaneous redox catalysts, with precisely controlled stoichiometry in the gas. A catalyst that would selectively reduce NO in preference to oxygen is difficult to find and is unnecessary. A mixture of catalysts that is active in oxidation and reduction may be quite adequate to the task. The interaction of different catalytic sites with several gaseous species remains to be unraveled by future investigators. 

The basic approach taken in the analytical studies of composite-propellant combustion represents a modification of the studies of double-base propellants. For composite propellants, it has been assumed that the solid fuel and solid oxidizer decompose at the solid surface to yield gaseous fuel and oxidizing species. These gaseous species then intermix and react in the gas phase to yield the final products of combustion and to establish the flame temperature. Part of the gas-phase heat release is then transferred back to the solid phase to sustain the decomposition processes. The temperature profile is assumed to be similar to the situation associated with double-base combustion, and, in this sense, combustion is identical in the two different types of propellants. 

Thermodynamic Functions of the Gases. To apply Eqs. (1-10), the free energies of formation, Ag , for all gaseous species as a function of temperature are required. Tabulated data were fit by a least-squares procedure to derive an analytical equation for AG° of each vapor species. For the plutonium oxide vapor species, the data calculated from spectroscopic data (3 ) were used for 0(g) and 02(g), the JANAF data (.5) were used and for Pu(g), data from the compilation of Oetting et al. (6) were used. The coefficients of the equations for AG° of the gaseous species are included in Table I. 

Naturally-occurring Trace Gases. The naturally emitted gaseous species subject to atmospheric oxidation include ... 

Chemical reactions involving aerosol particles in the atmosphere derive from the interaction of gaseous species with the liquid water associated with aerosol particles and with dissolved electrolytes. For example, the generation of HONO from nitrogen oxides... 

Although acetone was a major product, it was not observed by infrared spectroscopy. Flowing helium/acetone over the catalyst at room temperature gave a prominent carbonyl band at 1723 cm 1 (not show here). In this study, a DRIFTS (diffuse reflectance infrared Fourier transform spectroscopy) cell was placed in front of a fixed reactor DRIFTS only monitored the adsorbed and gaseous species in the front end of the catalyst bed. The absence of acetone s carbonyl IR band in Figure 3 and its presence in the reactor effluent suggest the following possibilities (i) acetone formation from partial oxidation is slower than epoxidation to form PO and/or (ii) acetone is produced from a secondary reaction of PO. 

In the full scale fire tests some additional gaseous species were studied specifically, i.e. formaldehyde. Not all gas species were studied in every test. Hydrogen cyanide and hydrogen chloride have only been studied in situations where evolution of these species were suspected. HCN and HC1 have only been studied as collective (2, 5 or 10 minutes) samples for each fire test. It is most preferable to follow the concentrations with direct reading instruments. This has been the case for carbon monoxide, carbon dioxide, oxygen and in three out of four cases for nitrous oxide. Drager tubes were used for measurements of nitrous oxides in the DIN 53436 test. 

Corrosion reactions of a metal with gaseous species such as oxygen, chlorine, sulfur containing molecules or water vapor to produce a thin layer of product phase are typical of ambipolar diffusion reactions. For example, metal oxidation... 

I0.6.8.I Cladding failure in oxide fuel pins of nuclear reactors. The long-term operational performance of nuclear fuel pins is critically governed by the reactions that occur in the gap between the fuel and its cladding. Ball et al. (1989) examined this for the cases of (1) Zircaloy-clad pellets of U02+, in a pressurised water reactor (PWR) and (2) stainless-steel-clad pellets of (U, P)02+, in a liquid-metal-cooled fast-breeder reactor (LMFBR). In particular they were interested in the influence of O potential on Cs, I, Te and Mo and the effects of irradiation on the gaseous species within the fuel-clad gaps. 

Figure 8.2 E-pH diagram for formate species oxidation and reduction. Soluble species concentrations (except H+) = 10 ° M. Gaseous species pressure = 1.00 atm. Soluble species and most solids are hydrated. No agents producing complexes or insoluble compounds are present other than HOH and OH .

As with metals, ceramic crystals are not perfect. They can contain all of the same types of defects previously described in Sections 1.1.3-1.1.5. What is unique about ceramic crystals, particularly oxide ceramics, is that the concentration of point defects, such as vacancies and interstitials, is not only determined not only by temperature, pressure, and composition, but can be influenced greatly by the concentration of gaseous species in which they come in contact (e.g., gaseous oxygen). The concentration of gaseous species affects the crystal structure, which in turn can affect physical properties such... 

At a simple level, precursors such as nitrates and carbonates can be used as starting materials instead of oxides they decompose to the oxides on heating at relatively low temperatures, losing gaseous species, and leaving behind fine, more reactive powders. 

Two terms are commonly used in the field to collectively refer to these species. NO, represents the sum of NO plus N02. These two species are combined in one term because they are interconverted in the sunlit atmosphere on a time scale of approximately 1 min, so their sum is a more conserved quantity than is either separately. However, no technique currently exists for directly measuring the sum of the NO and N02 concentrations each must be determined separately. NO /, which can be referred to as total reactive oxidized nitrogen, represents the sum of the species that have nitrogen in an oxidation state of + 2 or higher. However, techniques have been developed that are believed to measure the complete family concentration of at least the gaseous species in a single determination. 

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