O2 Stream Research Articles

ChemInform Abstract: The Influence of Oxygen Variation on the Crystal Structure and Phase Composition of the Superconductor YBa2Cu3O7‐x.

AbstractIn attempts to prepare a material with an O7.00 (x = 0 in the title compound) composition, the highest oxygen content achieved by annealing in an O2 stream at 440 °C for 24 h is 6.96 (iodometric determination).

ChemInform Abstract: IR Spectroscopic Characterization of Manganese Dioxides.

Abstractε‐MnO2 (obtained from aqueous Mn(NO3)2 solution, reflux, O2 stream) is characterized by a broad absorption from 900 to 360 cm‐1.

Shock tunnel study on a supersonic flow CO chemical laser.

A shock tunnel facility is fabricated and used for the study of a supersonic flow CO chemical laser. A high temperature mixture of CS2, CS, SZ, S and Ar is produced in a shock tube, where the thermal dissociation of CS2 diluted in Ar is accomplished by a reflected shock wave. The shock heated mixture is exhausted through supersonic nozzles mounted at the end of the tube and mixed with the supersonic streams of O2. Then, the vibrationally excited CO molecules are produced in the mixed streams by a chain reaction between CS and O2 initiated by S atoms. The present paper shows that the shock tunnel facility is successfully used to study the dependence of the small signal gain coefficient on the plenum temperature, plenum pressure and the transition branch.

Microcrack generation and its healing in the oxide scale formed on Fe-Cr alloys

Fe -base alloys containing 5, 10, and 20 wt. % Cr were oxidized in a stream of O2 at 750 and 900°C up to 264 hr. A “sulfur decoration” method was applied to detect the cracks generated in the scale during oxidation. This method revealed frequent crack generation and its healing in the scale. In the case of low-Cr alloys, the cracks are filled up with newly formed Fe-rich oxide but may be regenerated during further oxidation. Cracks are generated in the scale on an Fe-20Cr alloy also, although this alloy is not so severely attacked because of rapid healing.

Versatile Combustion-Amalgamation Technique for the Photometric Determination of Mercury in Fish and Environmental Samples

Abstract Total mercury in a variety of substances is determined rapidly and precisely by direct sample combustion, collection of released mercury by amalgamation, and photometric measurement of mercury volatilized from the heated amalgam. Up to 0.2 g fish tissue is heated in a stream of O2 (1.2 L/min) for 3.5 min in 1 tube of a 2-tube induction furnace. The released mercury vapor and combustion products are carried by the stream of O2 through a series of traps (6% NaOH scrubber, water condenser, and Mg(ClO4)2 drying tube) and the mercury is collected in a 10 mm diameter column of 24 gauge gold wire (8 g) cut into 3 mm lengths. The resulting amalgam is heated in the second tube of the induction furnace and the volatilized mercury is measured with a mercury vapor meter equipped with a recorder-integrator. Total analysis time is approximately 8 min/sample. The detection limit is less than 0.002 μg and the system is easily converted for use with other biological materials, water, and sediments.

Origin of water cluster ions in theDregion

Laboratory studies of the ions produced by the addition of water vapor into flowing streams of O2+ (or NO+) ions have led to a vapor phase reaction scheme starting with O2+ that seems likely to be responsible for the formation of the observed water cluster ions H3O+, H5O2+, H7O3+, etc. in the D region of the earth's ionosphere. Experimental difficulties have precluded quantitative rate constant measurements so far, and in addition the D-region water vapor concentration is uncertain so that only a qualitative scheme is possible at this time. The O2(¹Δg) photoionization source recently proposed by Hunten and McElroy is presumed to be the necessary precursor O2+ source. The reaction scheme involves O4+ and O2+·H2O as intermediate ions; these ions are possibly present in observable concentrations in the D region. Nitrous acid (HNO2) production is proposed to be an end result of successive hydrations of atmospheric NO+. The hydration of the atmospheric NO+ and O2+ ions and the formation of O4+ are expected to increase somewhat the effective electron recombination coefficient in the ionosphere.

ÉTUDE QUANTITATIVE DES RÉACTIONS D'OZONOLYSE: II. OZONATION DU trans-STILBÈNE

The ozonolysis of 1 mole of trans-stilbene (in CCl4) by a stream of O2–O3 leads to the formation of 0.677 mole of stilbene ozonide, 0.468 mole of benzaldehyde, and 0.089 mole of benzaldehyde diperoxide. This ratio, observed for 80–100% ozonizations, is independent of the olefin concentration, the ozone flow rate, and the temperature (in the range 25–45 °C). These observations are explained, if one assumes that the reaction between two zwitterions can follow two courses: (a) formation of a dimer peroxide (55%), and (b) elimination of oxygen with the formation of two molecules of benzaldehyde (45%).

A reversible nitrate electrode

AbstractA reversible nitrate electrode is described consisting of a bristle of platinum wires through which a stream of NO2 and O2 is maintained. The behaviour of the nitrate electrode is tested with respect to stability and reversibility against a silver electrode in molten silver nitrate. The standard EMF at 600° K was found to be E° = 0.176 V against a calculated value of E° = 0.175 V.