Non-Homogeneous Charge-Consistent Model for Acceleration of Iron in the Solar Corona

Acceleration of iron ions by a spherical shock wave moving through non-homogeneous solar corona is considered. The energy dependence of the mean charge of iron, _Fe(E), is determined by the characteristic acceleration time, T _a, trapping time, T _tr, and time for charge changes, T _q. The latter varies along with plasma number density during the propagation of the shock wave in the corona. Our calculations have demonstrated that adiabatic energy changes, Coulomb losses and shock broadening do not sufficiently influence the dependence _Fe(E). According to our estimations, the photoionizing processes can scarcely affect the ionic states of accelerated iron, except probably for the most powerful X10 class events.     

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Die Weiterentwicklung der Meßtechnik des Wassergehalts des Bodens auf thermischer Grundlage

Zusammenfassung Durch Untersuchungen vonJ. Bracht [3] und dem Verfasser wurde im Jahre 1940 festgestellt, daß die Wärmeleitfähigkeit des Bodens nicht bei allen Bodenarten eindeutig mit dem Wassergehalt zusammenhängt. Es wird eine Erklärung für diese Erscheinung durch die Verscjiedenheit der Wasserablagerung zwischen den Bodenpartikeln bei Wasseraufnahme und Wasserabgabe gegeben. Von allen Wärmekonstanten des Bodens ist nur die Wärmekapazität wahrscheinlich eindeutig abhängig von dem Wassergehalt des Bodens. Diese Größe kann am einfachsten als der Quotient aus der Wärmeleitfähigkeit und der Temperaturleitfähigkeit des Bodens bestimmt werden. Es mu\ also außer der Wärmeleitfähigkeit auch noch die Temperaturleitfähigkeit gemessen werden.In der vorliegenden Arbeit wird ein Verfahren zur Bestimmung dieser letzteren Größe beschrieben. Hierbei wird als Geber das Doppelthermometer benutzt, das zur Messung der Wärmeleitfähigkeit des Bodens vom Verfasser [2] beschrieben wurde. Von den beiden Thermometern dieses Doppelthermometers wird das eine in halbstündigen Intervallen je eine Viertelstunde lang geheizt. Gemessen wird dann außer dem Temperaturunterschied zwischen geheiztem und ungeheiztem Thermometer auch der Temperaturgang des ungeheizten Thermometers allein. Aus dem Temperaturunterschied zwischen beiden Thermometern wird in der üblichen Weise die Wärmeleitfähigkeit und aus der Amplitude des Temperaturganges und seiner Phasenverschiebung gegen die Heizung die Temperaturleitfähigkeit des Bodens berechnet.

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Summary Researches ofJ. Bracht [3] and of the present author have shown in 1940 that the thermal conductivity of the soil is not exactly coherent with the content of water in all kinds of soil. An explanation of this phenomenon is given by the difference of water deposit between the soil particles under conditions of imbilition and desiccation of water. Of all thermal constants of the soil solely the heat capacity probably is distinctly dependent on the water content of the soil. This value can be determined in the simplest manner as the quotient of thermal conductivity and thermal diffusivity of the soil. Beside thermal conductivity therefore thermal diffusivity must be measured too.A procedure for the determination of this last value is developed in this paper. The double thermometer which has been described by the author [2] for measuring the thermal conductivity is used as indicator. One of the two thermometers of this double thermometer is being heated during a quarter of an hour at intervals of half an hour. Beside the difference of temperature between heated and unheated thermometer the variation of temperature of the unheated thermometer itself is measured. Then the thermal conductivity is calculated in the usual manner from the difference of temperature between the two thermometers and the thermal diffusivity of the soil from the amplitude of the temperature variation and its shift of phase against heating.

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Résumé Des recherches deJ. Bracht [3] et de l'auteur en 1940 ont montré que la conductibilité calorifique de certains sols ne dépend pas uniquement de leur teneur en eau. On tente d'expliquer cette anomalie par le fait que l'eau s'insère différemment entre les particules du sol lors de l'imbibition et lors de la dessication. Parmi toutes les constantes calorifiques du sol, la capacité calorifique est probablement la seule qui soit en relation univoque avec la teneur en eau. Cette grandeur peut se définir le plus simplement par le quotient de la conductivité calorifique et de la transmission thermique du sol. Il faut donc mesurer séparément ces deux grandeurs.On décrit dans le présent mémoire un procédé permettant la mesure de la transmission thermique. On se sert comme indicateur du thermomètre double décrit par l'auteur [2] en vue de la mesure de la conductibilité du sol. L'un de ces thermomètres est chauffé pendant un quart d'heure toutes les demi-heures. On note alors non seulement la différence de température entre les deux instruments, mais encore les variations du thermomètre non chauffé: la différence de température permet comme d'ordinaire le calcul de la conductibilité, tandis que l'amplitude de la variation du thermomètre non chauffé et son décalage par rapport à l'autre permettent le calcul de la transmission thermique.

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Mit 4 Textabbildungen.     

Cyclicity in the Main and Upper Zones of the Bushveld Complex, South Africa: Crystallization from a Zoned Magma Sheet

The major element composition of plagioclase, pyroxene, olivine,and magnetite, and whole-rock ⁸⁷Sr/⁸⁶Sr data are presented forthe uppermost 2·1 km of the layered mafic rocks (upperMain Zone and Upper Zone) at Bierkraal in the western BushveldComplex. Initial ⁸⁷Sr/⁸⁶Sr ratios are near-constant (0·7073± 0·0001) for 24 samples and imply crystallizationfrom a homogeneous magma sheet without major magma rechargeor assimilation. The 2125 m thick section investigated in drillcore comprises 26 magnetitite and six nelsonite (magnetite–ilmenite–apatite)layers and changes up-section from gabbronorite (An₇₂ plagioclase;Mg# 74 clinopyroxene) to magnetite–ilmenite–apatite–fayaliteferrodiorite (An₄₃; Mg# 5 clinopyroxene; Fo₁ olivine). The overallfractionation trend is, however, interrupted by reversals characterizedby higher An% of plagioclase, higher Mg# of pyroxene and olivine,and higher V₂O₅ of magnetite. In the upper half of the successionthere is also the intermittent presence of cumulus olivine andapatite. These reversals in normal fractionation trends definethe bases of at least nine major cycles. We have calculateda plausible composition for the magma from which this entiresuccession formed. Forward fractional crystallization modelingof this composition predicts an initial increase in total iron,near-constant SiO₂ and an increasing density of the residualmagma before magnetite crystallizes. After magnetite beginsto crystallize the residual magma shows a near-constant totaliron, an increase in SiO₂ and decrease in density. We explainthe observed cyclicity by bottom crystallization. Initiallymagma stratification developed during crystallization of thebasal gabbronorites. Once magnetite began to crystallize, periodicdensity inversion led to mixing with the overlying magma layer,producing mineralogical breaks between fractionation cycles.The magnetitite and nelsonite layers mainly occur within fractionationcycles, not at their bases. In at least two cases, crystallizationof thick magnetitite layers may have lowered the density ofthe basal layer of melt dramatically, and triggered the proposeddensity inversion, resulting in close, but not perfect, coincidenceof mineralogical breaks and packages of magnetitite layers. KEY WORDS: layered intrusion; mineral chemistry; isotopes; magma; convection; differentiation     

Thermal history of the unsaturated zone at Yucca Mountain,Nevada, USA

Secondary calcite, silica and minor amounts of fluorite deposited in fractures and cavities record the chemistry, temperatures, and timing of past fluid movement in the unsaturated zone at Yucca Mountain, Nevada, the proposed site of a high-level radioactive waste repository. The distribution and geochemistry of these deposits are consistent with low-temperature precipitation from meteoric waters that infiltrated at the surface and percolated down through the unsaturated zone. However, the discovery of fluid inclusions in calcite with homogenization temperatures (T_h) up to ∼80 °C was construed by some scientists as strong evidence for hydrothermal deposition. This paper reports the results of investigations to test the hypothesis of hydrothermal deposition and to determine the temperature and timing of secondary mineral deposition. Mineral precipitation temperatures in the unsaturated zone are estimated from calcite- and fluorite-hosted fluid inclusions and calcite δ¹⁸O values, and depositional timing is constrained by the ²⁰⁷Pb/²³⁵U ages of chalcedony or opal in the deposits. Fluid inclusion T_h from 50 samples of calcite and four samples of fluorite range from ∼35 to ∼90 °C. Calcite δ¹⁸O values range from ∼0 to ∼22‰ (SMOW) but most fall between 12 and 20‰. The highest T_h and the lowest δ¹⁸O values are found in the older calcite. Calcite T_h and δ¹⁸O values indicate that most calcite precipitated from water with δ¹⁸O values between −13 and −7‰, similar to modern meteoric waters.     

A Pull-Up Shallow Water Seismometer

An inexpensive Pull-Up Shallow Water Seismometer (PUSS) has been designed and built to conduct long range seismic refraction experiments in the North Sea and the continental shelf around Britain, with the particular goal of studying the crustal and lithospheric structure under the epeirogenic basin of the North Sea. Signals from a gimbal-mounted 3-component geophone and a hydrophone are frequency modulated and mixed with clock and flutter correction signals before being recorded on a standard speed cassette tape recorder, with one hour of recording time. A 100 hour programmable timer allows the interval between the time of reset of the clock and each shot window of optional 5 or 10 min duration, to be preselected. The PUSS is launched and recovered using a pull-up technique originally developed for current meters. The replay system is also described.In May 1976 sea trials of 5 PUSSes were conducted along a 200 km refraction line in the North Sea. The encouraging performance of the equipment resulted in the decision to build a further 10 units and to proceed with a 400 km refraction line planned for the summer of 1977.     

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Fluxes of organic carbon in Manukau Harbour, New Zealand

We collated information on the sources and sinks of organic carbon in Manukau Harbour, a shallow temperate estuary. Two contrasting inner harbor regions were considered; the northern region, which is urbanized and receives a major load of sewage wastewater, and the southern region, where allochthonous inputs are dominated by the runoff from small rural streams. Although high levels of dissolved nitrogen in the wastewater supported phytoplankton blooms in the northern region, total primary production there was similar to that in the southern region (ca. 300 g C m^?2yr^?1). By contrast, high concentrations of organic carbon in the wastewater resulted in an additional input to the northern region of 120 g C m^?2 yr^?1. Loads from runoff and streams to both regions were low. At 350 g C m^?2 yr^?1, total respiration in the northern region exceeded total production, so the region was slightly heterotrophic. Respiration was lower in the southern region (270 g C m^?2 yr^?1), which was net autotrophic. Some carbon was exported from each region to the outer harbour (50–80 g C m^?2 yr^?1). Dissolved oxygen levels in the northern region were somewhat depleted at times; and the high numbers of microzooplankton indicated consumption was enhanced there. Apart from a relatively small area of organic enrichment close to the wastewater discharge, benthic consumers in the harbor appeared to be limited by physical disturbance (by wind-waves) rather than by food availability. Improved wastewater treatment is expected to substantially reduce the allochthonous input to the northern region, with the total input of carbon in the future being only slightly higher than that to the southern region.     

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