EPR measurement of the effect of glass composition on the oxidation states of europium

The techniques of electron paramagnetic resonance (EPR) were used to measure the concentration ratio of Eu²⁺ to Eu³⁺ in quenched silicate liquids as a function of their compositions. The compositional end members were CaAl₂Si₂O₈ and either MSiO₃ or M₂Si0₄, M = Mg, (Ca_0.5, Mg_0.5), and Ca. All of the liquids were quenched from 1650 ± 25°C, 10^?6.9±0.6 atm of oxygen, and 10^?6.1±0.6 atm total pressure. For a particular choice of M, the ratio of Eu²⁺ to Eu³⁺ increased as much as a factor of 24 with increasing atomic ratio (Al + Si)/(O); for a constant value of (Al + Si)/(O), the ratio of Eu²⁺ to Eu³⁺ increased in the order Mg > (Ca_0.5,Mg_0.5) >Ca. In order to interpret the compositional dependence of the redox equilibrium of Eu in a systematic manner, the concept of a solvent coefficient was introduced.     

Viking 1 Lander on the surface of mars: Revised location

Late in 1977, the periapsis altitude of the Viking Orbiters was lowered from 1500 to 300 km. The higher resolution of pictures taken at the lower altitude (8 m/pixel) permitted a more accurate determination of the location of the Viking 1 Lander by correlating topographic features seen in the new pictures with the same features in lander pictures. The position of the lander on Viking Orbiter picture 452B11 (NGF Rectilinear) is line 293, sample 1099. This location of the Viking 1 Lander has been used in a revision of the control net of Mars (M.E. Davies, F.Y. Katayama, and J.A. Roth, R2309 NASA, The Rand Corp., Feb. 1978). The new areographic coordinates of the lander are lat 22.483° N and long 47.968° W. The new location is estimated to be accurate to within 50 m.     

Survival of juvenile spot (Leiostomus xanthurus) exposed to bromochlorinated and chlorinated sewage in estuarine waters

The acute toxicity of chlorinated and bromochlorinated treated sewage waste was determined with spot, Leiostomus xanthurus. The halogenated sewage waste was generated in a pilot plant located at the James River Sewage Treatment Plant, Newport News, Va. The 96 h and 144 h LC50's were 0·23 mg/l (measured residual) for chlorine and 0·25 mg/l (measured residual) for bromine chloride. These concentrations are considerably higher than those which would be produced by optimal halogenation rates for disinfection or maximum superhalogenation rates permitted by pilot plant equipment and normal effluent dilution rates.     

High spatial resolution Galactic 3D extinction mapping with IPHAS

We present an algorithm (MEAD, for 'Mapping Extinction Against Distance') which will determine intrinsic  ( r '− i ')  colour, extinction, and distance for early-A to K4 stars extracted from the IPHAS   r '/ i '/Hα  photometric data base. These data can be binned up to map extinction in three dimensions across the northern Galactic plane. The large size of the IPHAS data base (∼200 million unique objects), the accuracy of the digital photometry it contains and its faint limiting magnitude  ( r '∼ 20)  allow extinction to be mapped with fine angular (∼10 arcmin) and distance (∼ 0.1 kpc) resolution to distances of up to 10 kpc, outside the solar circle. High reddening within the solar circle on occasion brings this range down to ∼2 kpc. The resolution achieved, both in angle and depth, greatly exceeds that of previous empirical 3D extinction maps, enabling the structure of the Galactic Plane to be studied in increased detail. MEAD accounts for the effect of the survey magnitude limits, photometric errors, unresolved interstellar medium (ISM) substructure and binarity. The impact of metallicity variations, within the range typical of the Galactic disc is small. The accuracy and reliability of MEAD are tested through the use of simulated photometry created with Monte Carlo sampling techniques. The success of this algorithm is demonstrated on a selection of fields and the results are compared to the literature.