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Treatment of C60 with osmium tetroxide and pyridine gives the osmate ester (2:1 adduct) establishing that oxygen functionality can be added to C60 without disrupting the carbon framework.
This paper reports XPS analysis of jet exhaust particulate from a B737, Lear, ERJ, and A300 aircraft during the APEX III NASA led field campaign. Carbon hybridization and bonding chemistry are identified by high-resolution scans about the C1s core-shell region. Significant organic content as gauged by the sp3/sp2 ratio is found across engines and platforms. Polar oxygen functional groups include carboxylic, carbonyl and phenol with combined content of 20 percent or more. By lower resolution survey scans various elements including transition metals are identified along with lighter elements such as S, N, and O in the form of oxides. Burning additives within lubricants are probable sources of Na, Ba, Ca, Zn, P and possibly Sn. Elements present and their percentages varied significantly across all engines, not revealing any trend or identifiable cause for the differences, though the origin is likely the same for the same element when observed. This finding suggests that their presence can be used as a tracer for identifying soots from aircraft engines as well as diagnostic for monitoring engine performance and wear.
Investigation in 19 conscious dogs of the importance of the sympathetic nervous system in the coronary and cardiac response to altitude (hypoxic) hypoxia. Beta-adrenergic blockade was used to minimize the cardiac effect associated with sympathetic receptors. It is shown that the autonomic nervous system, and particularly the sympathetic nervous system, is responsible for the increase in ventricular function and myocardial oxygen consumption that occurs during hypoxia. Minimizing this response through appropriate conditioning and training may improve the operating efficiency of the heart and reduce the hazard of hypoxia and other environmental stresses, such as acceleration, which are encountered in advanced aircraft systems.
Fluorine and oxygen effects on work function of polycrystalline tungsten
Direct photolysis of O3 and quenching of O(1D) by N2 provide abundant sources of fast oxygen atoms for earth's lower atmosphere. The concentration of atoms with energy above 0.7 eV may exceed the concentration of O(1D) for all altitudes below 18 km, and these atoms may play an important role in lower-atmospheric chemistry. Distribution functions for O(3P) are given for the energy interval 0.1-1.3 eV and a range of altitudes from 0 to 62 km.
High-pressure experiments in a piston-cylinder apparatus with silver-palladium containers were conducted to study the stability of synthetic armalcolite, (Fe,Mg)Ti2O5, as a function of pressures up to 15 kbar at 1000, 1100, and 1200 C. Three armalcolite compositions were used, each with an initial Fe/(Fe + Mg) ratio of 0.5. Composition I contained no zirconium, whereas compositions II and III were prepared with 4% and 10% by weight ZrO2. Difference in stability due to the presence or absence of Zr in these synthetic armalcolites is discussed. 4 wt% ZrO2 appears to saturate armalcolite at 1200 C and 1 atm. Zirconium is found to reduce armalcolite stability, but this effect is not great. The stability of armalcolite as a function of oxygen fugacity is determined thermogravimetrically at 1200 C and 1 atm. Knowledge of the range of oxygen fugacity at which armalcolite is stable and of the equilibrium oxide mineral assemblages outside this range provides important information about lunar cooling histories in terms of oxygen fugacity.
An analysis is conducted of the requirement for the conduct of spherically symmetric droplet-combustion experiments on space platforms, on the basis of a novel time-dependent computational droplet combustion model that allows the time- and temperature-dependent transport characteristics to be incorporated. While at low oxygen indices the droplet burning extinction becomes a strong function of oxygen index, it becomes a weaker function at higher oxygen index values. The oxygen index that separates these two ranges are dependent on the diluent, being higher for He and lower for N.
Spherical detonations of acetylene oxygen nitrogen mixtures as function of nature and strength of initiation
Kinetics and mechanism of enhanced oxidation of platinum in activated oxygen as function of partial pressure of oxygen atoms
Operation Everest II was designed to examine the physiological responses to gradual decompression simulating an ascent of Mt Everest (8,848 m) to an inspired PO2 of 43 mmHg. The principal studies conducted were cardiovascular, respiratory, muscular-skeletal and metabolic responses to exercise. Eight healthy males aged 21-31 years began the "ascent" and six successfully reached the "summit", where their resting arterial blood gases were PO2 = 30 mmHg and PCO2 = 11 mmHg, pH = 7.56. Their maximal oxygen uptake decreased from 3.98 +/- 0.2 L/min at sea level to 1.17 +/- 0.08 L/min at PIO2 43 mmHg. The principal factors responsible for oxygen transport from the atmosphere to tissues were (1) Alveolar ventilation--a four fold increase. (2) Diffusion from the alveolus to end capillary blood--unchanged. (3) Cardiac function (assessed by hemodynamics, echocardiography and electrocardiography)--normal--although maximum cardiac output and heart rate were reduced. (4) Oxygen extraction--maximal with PvO2 14.8 +/- 1 mmHg. With increasing altitude maximal blood and muscle lactate progressively declined although at any submaximal intensity blood and muscle lactate was higher at higher altitudes.
Dissociative excitation of CO2 by electron impact was studied using the methods of translational spectroscopy and angular distribution analysis. Earlier time of flight studies revealed two overlapping spectra, the slower of which was attributed to metastable CO(a3 pi) fragments. The fast peak is the focus of this study. Threshold energy, angular distribution, and improve time of flight measurements indicate that the fast peak actually consists of five overlapping features. The slowest of the five features is found to consist of metastable 0(5S) produced by predissociation of a sigma u + state of CO2 into 0(5S) + CO(a3 pi). Oxygen Rydberg fragments originating directly from a different sigma u + state are believed to make up the next fastest feature. Mechanisms for producing the three remaining features are discussed.
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A complete description of pulmonary measurements obtained after continuous O2 exposure of 13 healthy men at 3.0 ATA for 3.5 h is presented. Measurements included flow-volume loops, spirometry, and airway resistance(n = 12); CO diffusing capacity (n = 11); closing volumes (n= 6); and air vs. HeO2 forced vital capacity maneuvers (n = 5). The average difference in maximum mid expiratory flows at 50 percent vital capacity on air and HeO2 was found to be significantly reduced postexposure by 18 percent. Raw and CO diffusing capacity were not changed postexposure. It is concluded that the relatively large change in forced expiratory flow at 25-75 percent of vital capacity compared with the mean forced expiratory volume in 1 s, the reduction in density dependence of flow, and the normal Raw postexposure are all consistent with flow limitation in peripheral airways as a major cause of the observed reduction in expiratory flow.
The stability of synthetic armalcolite was determined as a function of oxygen fugacity with particular regard to the oxidation state of iron and titanium. The equilibrium pseudobrookite (armalcolite) composition was measured at 1200 C under various conditions of oxidation typical of the lunar environment. These data, when compared with published descriptions of mare basalts, provide information about the conditions of crystallization of armalcolite-bearing lunar rocks. Some information about the crystal chemistry of armalcolite was obtained from X-ray diffraction and electron microprobe analyses of synthetic armalcolite and Zr-armalcolite. Further data were gathered from a comparison of the Mossbauer spectra of a phase pure stoichiometric armalcolite and one containing appreciable amounts of trivalent titanium.
Time analysis study by photography of combustion processes, gas explosion, and wave propagation in vessels of variable volume using hydrogen-oxygen
Probe field emission studies of work function and energy distribution of cesium-oxygen-tungsten system
A metal/ceramic Marchuk tube was used to measure work functions of oxygen-doped tantalum, to determine applicability of the material to plasma-mode thermionic converters. Oxygen-doped tantalum was shown to increase in work function monotonically with oxygen doping in the range 0.1 to 0.3 atomic percent. Oxygenated test emitters were run at an average temperature of 2165 K and a T/T sub Cs ratio -5.8 to observe the influence of oxygen depletion. Bare work function decreased with outgassing of oxygen. Projections were made based on outgassing kinetics and area/volume ratios to calculate the longevity of oxygen doping in a practical converter. Calculations indicated that the program goal of 10,000 hr could be achieved at 1800 K with an initial oxygen doping of 1 atomic percent and a practical emitter area/volume ratio.
Schlieren photography study of combustion of hydrogen-oxygen mixture and velocity variation of propagated shock waves with time as a function