Thermodynamic stability of CoOOH and its coprecipitation with manganese

A precipitate of cobalt oxyhydroxides formed by bubbling oxygen through a dilute solution of Co(NO₃)₂ held at pH 9.0 and 25°C was aged for 23 months in contact with the original solution, with access to atmospheric oxygen. Co₃O₄ and CoOOH were identified in the precipitate by X-ray diffraction. Chemical equilibria involving these solids were evaluated by measurements of solution pH and Co²⁺ activities and by redox potential measurements and gave a $\text{ΔG}{}_{\mathrm{coOOH}}{}^0$ of $\text{?92.3 ± 0.5 kcal/mole}$. This value and other thermodynamic data show relative feasibility of hypothetical reaction steps and changes in reaction paths during automated coprecipitation titrations and subsequent aging of a precipitate that finally contained βMnOOH, MnO₂ (birnessite) and CoOOH.     

Correlation of foreshocks and aftershocks and asperities

A close correlation in spatial distribution of local seismic activity and energy release patterns before and after the 1979 Petatlan, Mexico earthquake suggests heterogeneity within the fault plane of this major low-angle thrust event associated with subduction along the Middle America Trench. A simple two-asperity model is proposed to account for the complexity. Foreshocks and aftershocks of the neighboring 1981 Playa Azul earthquake showed a similar pattern. As both events occurred at the junction of the Orozco Fracture Zone and the Middle America Trench, we speculate that the observed complex fault plane is caused by subduction of the rugged ocean floor of the Orozco Fracture Zone. Short-term precursory seismicity prior to the Petatlan earthquake can be explained by using the asperity model and migration of a slip front from the south-east to the north-west across the main shock source region.     

14C content of ten meteorites measured by tandem accelerator mass spectrometry

¹⁴C has been measured in three North American and seven Antarctic meteorites with the Chalk River MP tandem accelerator. In most cases cosmogenic¹⁴C, which is tightly bound, was separated from absorbed atmospheric radiocarbon by stepwise heating extractions. Terrestrial ages obtained by comparing cosmogenic¹⁴C in the meteorite to that in Bruderheim are (7.2 ± 0.6) × 10³ years for Yamato 7304, (11.6 ± 0.4) × 10³ years for Estacado, and range from (32.7 ± 0.5) × 10³ to (41.0 ± 0.8) × 10³ years for six meteorites recovered at Allan Hills and its vicinity. The present upper limit to age determination by the accelerator method varies from 50 × 10³ to 70 × 10³ years depending upon mass and carbon content of the sample. The natural limit caused by cosmic ray production of¹⁴C in silicate rocks at 2000 m elevation is estimated to be (55 ± 5) × 10³ years. “Weathering ages” were estimated for the Antarctic meteorites from the specific activity of loosely-bound CO₂ considered to be absorbed from the terrestrial atmosphere on weathering. The accelerator measurements are in accordance with previous low-level counting measurements but have higher precision and sensitivity.     

Parameterization of meridional energy flux in a one-dimensional climate model

Summary The zonally averaged meridional energy transport is parameterized in terms of the zonally averaged temperature gradient and its radiative equilibrium value. Two climate regimes are identified: radiative equilibrium and isothermal climates. The transport and temperature gradient are intermediate between corresponding quantities of these two climates. The parameterization assumes a linear increase of transport as temperature gradient departs from its radiative equilibrium value. The parameterization is formulated using a one-dimensional climate model. Ice-albedo feedback provides the mechanism for climate changes. The parameterization works well for climates associated with seasonal changes.

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Parameterisierung des meridionalen Energiestromes in einem eindimensionalen Klimamodell

Zusammenfassung Der zonal gemittelte, meridionale Energietransport wird in Abhängigkeit vom zonal gemittelten Temperaturgradienten und seinem Strahlungsgleichgewicht parameterisiert. Zwei Klimaregime können identifiziert werden: Strahlungsgleichgewicht und isothermes Klima. Der Transport und der Temperaturgradient befinden sich zwischen den korrespondierenden Werten dieser zwei Klimate. Die Parameterisierung nimmt eine lineare Zunahme des Transportes mit der Abweichung des Temperaturgradienten vom seinem Strahlungsgleichgewichtswert an. Die Parameterisierung wird unter Verwendung eines eindimensionalen Klimamodelles formuliert. Die Eis-Albedo-Rückkopplung liefert den Mechanismus für Klimadnderungen. Die Parameterisierung funktioniert gut fur Klimate, welche jahreszeitliche Anderungen beinhalten.

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With 4 Figures     

Application of the technique to ellipitical markers deformed by pressure-solution

Compression and extension axes are deduced from quartz deformation lamellae in a quartzite and a graywacke folded into an asymetrical syncline. Deformation lamellae fabrics in the two sandstones are distinctly different. In the graywacke, regardless of bedding orientation or position on the fold, compression axes are normal or nearly normal to the axial planar rough cleavage. Extension axes generally lie in the cleavage plane, parallel to dip. In most quartzite samples, compression axes are parallel or subparallel to bedding, at high angles to the fold axis and extension axes are normal to bedding. Two samples from the very base of the formation indicate compression parallel to the fold axis with extension parallel to bedding, at high angles to the fold axis. One of these two shows both patterns. The lamellae fabric geometry in these two samples suggests the presence of a neutral surface in the quartzite. The lamellae-derived compression and extension axes are in good agreement with the buckling behavior of a viscous layer (quartzite) embedded in a less viscous medium (graywacke and shale below and shale and carbonate above).     

Rapid sampling of organic matter in flooded soils and sediments

Estuaries and Coasts - A coring system using a compressed air supply and a sediment shaking procedure using a soil dispersant are described which greatly simplify and shorten the task of...     

使用微机的自动气象站

本文综述了应用微型计算机作为自动气象站的核心部分应考虑的要点。阅读本文并不要求读者掌握微机的基本知识。本文所描述的原理涉及来自气象感应元件的信号处理、计算机硬件性能的选择、编制程序的语言和技术、最终结果的输出方法等。作为一个实例,本文介绍了一个用于向公众展示当天气象要素及气候统计资料的自动气象站。     

In-situ neutron flux,Cl production and groundwater evolution in crystalline rocks at Stripa, Sweden

The meteoric input of³⁶Cl due to cosmogenic or nuclear-weapon-produced³⁶Cl cannot contribute significantly to the³⁶Cl present in the saline groundwaters (up to 700 mg l⁻¹ Cl⁻) from the Stripa granite. The extent of in-situ production of³⁶Cl has been estimated on the basis of the neutron fluxes within the granite and its surrounding leptite. The³⁶Cl present in the groundwaters is attributed to either admixture of labelled Cl⁻ from the leptite with Cl⁻ from the granite or to the total derivation of groundwater chlorinity within the leptite followed by radiochemical ingrowth of³⁶Cl during subsequent groundwater residence within the granite. The chloride derived from the leptite may be either matrix chloride or chloride from an external source which has had a long residence time within the leptite. The implications of³⁶Cl in-situ production for the estimation of groundwater residence times and for the geochemical evolution of groundwater chlorinity are discussed.