Inactive gases

In the majority of cases the solubility decreases with rise of temperature, indicating that heat is absorbed when the gas is abstracted from its saturated solution with the group of inactive gases, according to Estreicher ( 126), the opposite effect is observed. 

A family of colorless, inactive gases was unknown at the time Mendeleev conceived his periodic table. Eventually, these gases were discovered on Earth in the late 1890s. What group does this family occupy in the modem periodic table ... 

The relative work function and the relative electrode potential of electrodes in aqueous solutions and in inactive gases can be measured by a vibrating capacitor technique called Kelvin s method [Samec-Johnson-Doblhofer, 1992]. The Kelvin method estimates the difference in the work function between a test electrode and a Kelvin probe (KF) by measuring the applied voltage V at which the difference in the outer potential ij s- l KP between the test electrode and the Kelvin probe becomes zero (V = liJs - i Kp) as shown in Pig. 4—28. 

Above we have looked at the translational spectra of binary systems. These are obtainable experimentally at sufficiently low densities, especially when absorption of the infrared inactive gases is studied. An induced spectrum may be considered to be of a binary nature if the integrated intensity varies as density squared. In that case, the shape of the densities-normalized absorption coefficient, cc/q Q2, is invariant, regardless of the densities employed. ... 

Noble gases The elements helium, neon, argon, krypton, xenon and radon. Family of inactive gases found in group 8A of the periodic table. 

Fig. 2. The change in the dissolution velocity of A1203 on the heating of kaolin in various chemically inactive gases. The effect consists of a change in the recrystallization velocity and is of interest with reference to the problem of the carrier (--------air -------CO --------C02).

Figure 7. The difference thermal trace superimposed on the quantified gas products from EDD. H2O, NH4NO3 aerosol and any IR inactive gases are excluded.

In some cases it is not possible to prevent the dilution of radioactive gases with inactive gases such as air before they are processed. Examples of this... 

Other phenomena concern the influence of ambient gases which are not corrosive in the usual sense of the term, an influence which has also proved to be of considerable interest in relation to corrosion and especially to the problems of passivation. A long series of experiments was performed in which it was established that the reactivity and the adsorption capacity of a great number of substances, perhaps of all substances, is considerably influenced by chemically inactive gases. Small quantities of gas may be dissolved, as, for instance in silica and alumina, first in the outermost layers and then gradually penetrate to deeper levels. 

Chemically, carbon dioxide is not very reactive, and it is often used as an inactive gas to replace air when the latter might interact with a substance, for example in the preparation of chromium II) salts (p. 383). Very reactive metals, for example the alkali metals and magnesium can, however, continue to bum in carbon dioxide if heated sufficiently, for example... 

In recent investigations, it appears that the interfadal potential between a metal electrode and an aqueous solution somehow survives after the electrode is taken out of the aqueous solution and into ultra high vacuum or an inactive gas phase [Wagner, 1993]. This circumstance is referred to as emersion . As shown in Fig. 4—26, the electrode potential E m of the emersed electrode is... 

This equation applies also to the electrodes emersed from aqueous solution into inactive gas (Fig. 4-28 b) as shown in Eqn. 4-40, which gives the relationship between the electrode potential Em of an emersed electrode and the potential Ejcp of the Kelvin probe ... 

The switch fimction of the a-subunit of the heterotrimeric G-proteins is foimded on the change between an active G -GTP confirmation and an inactive Ga-GDP conformation. The structural difference between the two conformations was explained for the transducin, G, , by crystallization and structural characterization of the inactive GDP form and the active GTPyS form (Lambright et al., 1994). The structures of both forms of Gt, are shown in Fig. 5.19. 

The Py-complex does not show any great structural differences in the free and G -boimd forms. Activation of the Py-complex for the interaction with the corresponding effector molecule (see below) appears to be based only on its release from the inactive Ga GDP Py complex. The Ga-subimit has the function of a negative regulator here, that inactivates the PY-compIex by masking the interaction region for signal proteins next in the sequence. 

E. C. C. Baly and H. M. Duncan studied the decomposition of ammonia by means of a hot platinum wire. Two types of ammonia may be prepared—an inactive and an active modification—which are decomposed to different extents by the same quantity of energy. The active form is obtained by the slow withdrawal of ammonia from a cylinder containing the compressed gas by warming the cone. aq. soln. and drying the gas by quicklime and by isothermal evaporation of the liquefied gas at its b.p. The inactive form is obtained by the rapid evaporation of the liquefied gas. The inactive gas slowly recovers its activity on remaining in contact with the liquefied gas. The same effect can be produced by gently warming the gas by means of a platinum wire heated at 200°. In order to observe these phenomena, the platinum wire must be activated in the same way as is customary in W. Ostwald s process for the catalytic oxidation of ammonia in air to nitric acid. Alternatively,... 

For an inactive gas, helium has a surprising number of applications. It is used in low-temperamre research, for filling balloons and dirigibles (blimps), to pressurize rocket fuels, in welding operations, in lead detection systems, in neon signs, and to protect objects from reacting with oxygen. 

Though the reaction temperature, of course, generally depends on the employed solvent, it is within a temperature range of from—20 ° C. to near the boiling point of the solvent. The reaction is preferably carried on in an atmosphere of such an inactive gas as nitrogen, helium and the like. Thus, the amide derivatives of the objective products are obtained under relatively mild conditions in high yields and simplicity without oxidation of the reactant. 

If necessary, the reaction is carried on in an atmosphere of an inactive gas such as nitrogen, helium and the like to prevent from producing undesirable byproducts and coloring, thereby to yield the... 

The catalytic activities of acids and bases for Claus reaction were investigated by supporting these on Chromosorb-A (a relatively inactive gas chromatographic solid support) and other materials and obtaining the relative activities of these compounds for Claus reaction based on initial rates at 240°C. The experiments were carried out in a fixed-bed integral flow reactor using low partial pressures of reactants. Acidity did not enhance catalytic activity but the deposition of bases (1-8 wt %) induced a dramatic increase in the catalytic activity for Claus reaction. Attempts were made to measure the basicities of these catalysts and relate these to the observed catalytic activity for Claus reaction. 

The pathways from GA] 2 l hyde have in conmion the loss of carbon-20 to give the biologically active Cj g-GAs, and (in plants) 2B-hydroxylations to give biologically inactive GAs. In higher... 

On February 1, 1895, W. Ramsay received a short letter from K. Miers, a British museum employee. By that time Ramsay had already been acclaimed as the discoverer of argon and we may think Miers did not choose him by chance. Miers wrote about the experiments of the American researcher W. Hildebrand, performed at the US Geological Institute as early as 1890. Upon heating of some thorium and uranium minerals (for instance, cleveite) a chemically inactive gas was liberated its spectrum was similar to that of nitrogen and contained new lines. 

Evidently, Ramsay believed that Hildebrand s inactive gas could be argon therefore, he agreed with Miers and on February 5, he acquired a small amount of cleveite. Ramsay himself, however, was busy with studying argon and attempting to prepare its compounds and, therefore, asked his pupil D. Matthews to carry out the experiment. Matthews treated the mineral with hot sulphuric acid and, like Hildebrand, observed the formation of bubbles of a gas resembling nitrogen. 

As for the coolant, helium, a chemically inactive gas, is used. It is compatible with the structural material and graphite, and it contributes to the reactor s high-temperature features. 

For 2 -hydroxylated biologically inactive GA metabolites [25] including GAg, GA29, and GA34, the glucosylation leads to a more polar derivative, possibly allowing better transport and compartmentation, such as into the vacuole [7]. 

Surlace is cmsslinked and gelled by contacting an inactive gas that was excited, using high-fiequency electrical waves on the surface of the polymer using the radical polymerization method (suspension polymerization or emulsification polymerization... 

The organization of one TPR or TPO experiment is somehow different in comparison with that one applied for temperature-programmed desorption. For example, the sample has to be purged with inactive gas, before exposure to active (reductive or oxidative) gas. These differences can be seen in Table4.1, which presents the organisation of both TPD and TPR/TPO experiments. 

It was clear that Harwell and Risley would not have the resources to tackle the project for some considerable time, but there were other options. A paper on the HTR was prepared for a meeting of the European Atomic Energy Society to be held in Rome in November 1957, when the subject would be gas-cooled reactors, including a session at the end on other types of inactive gas reactors and gas reactors where fission products are released . ... 

The choice of tracer gas for the measurements is Kr-85 It has a long half-life so that it can be stored for application when needed. It is a noble gas which is chemically inactive giving a low radio toxicity as it is readily removed in case of accidental contamination. 

Iron Sulfur Compounds. Many molecular compounds (18—20) are known in which iron is tetrahedraHy coordinated by a combination of thiolate and sulfide donors. Of the 10 or more stmcturaHy characterized classes of Fe—S compounds, the four shown in Figure 1 are known to occur in proteins. The mononuclear iron site REPLACE occurs in the one-iron bacterial electron-transfer protein mbredoxin. The [2Fe—2S] (10) and [4Fe—4S] (12) cubane stmctures are found in the 2-, 4-, and 8-iron ferredoxins, which are also electron-transfer proteins. The [3Fe—4S] voided cubane stmcture (11) has been found in some ferredoxins and in the inactive form of aconitase, the enzyme which catalyzes the stereospecific hydration—rehydration of citrate to isocitrate in the Krebs cycle. In addition, enzymes are known that contain either other types of iron sulfur clusters or iron sulfur clusters that include other metals. Examples include nitrogenase, which reduces N2 to NH at a MoFe Sg homocitrate cluster carbon monoxide dehydrogenase, which assembles acetyl-coenzyme A (acetyl-CoA) at a FeNiS site and hydrogenases, which catalyze the reversible reduction of protons to hydrogen gas. 

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