Parameters of the fluid core resonance inferred from superconducting gravimeter data

We have estimated the parameters of fluid core resonance (FCR) due to the nearly diurnal free wobble of the Earth's core based on the superconducting gravimeter (SG) data obtained at the following four observation sites; Esashi and Matsushiro in Japan, Canberra in Australia and Membach in Belgium. By fitting the tidal admittances normalized with the O1 wave at each site to a model of the damped harmonic oscillator, we obtained values of 429.66 ± 1.43 sidereal days, 9350–10,835, −4.828E−4 ± 3.4E−6, −3.0E−5 ± 4.5E−6 for the eigenperiod, the Q-value and the real and imaginary parts of the resonance strength, respectively. Our values obtained from only using the gravity data are very consistent with those inferred from the VLBI nutation data. Our study strongly indicates that the systematic difference between two estimations from the gravity and the nutation in particular for the Q-value, which has been shown in previous works, is mainly caused by the inaccurate correction for the ocean tide effects. The error in the ocean tide correction is discussed based on the comparison among four global ocean tide models; Schwiderski model (1980), NAO.99b (Matsumoto et al., 2000), CSR4.0 (Eanes and Bettadpur, 1994) and GOT99.2b (Ray, 1999).     

Experimental determination of Ni diffusion coefficients in olivine and their dependence on temperature, composition, oxygen fugacity, and crystallographic orientation

Diffusion couple experiments were carried out with San Carlos olivine (Fo₉₀) and NiFe alloys (Ni₁₀₀, Ni₉₇Fe₃, Ni₉₀Fe₁₀) or other olivine compositions (Fo₁₀₀, Fo₂₅) in order to determine the dependence on temperature, oxygen fugacity, composition and crystallographic orientation of Ni diffusion coefficient (D_Ni) in olivine. Experiments at 1 atmosphere total pressure cover a temperature range of 900-1445°C with run durations from 48 to 2155 h at different oxygen fugacities. In an Arrhenius plot the best fit for all data for Fo₉₀ yields an activation energy (E_D) of 220 ± 14 kJ/mol and an fO₂ dependence of (1/4.25)·Δ log fO₂ = Δ log D_Ni. The relationship between diffusion coefficients along different crystallographic axes at 1200°C is given by D_[001] ≈ 6·D_[100] ≈ 6·D_[010]. D_Ni depends strongly on the major element (i.e. Fe/Mg) composition of olivine and decreases by about 1 order of magnitude as the olivine composition changes from Fo₃₅ to Fo₉₀. Thus, experimental investigations in Fe-free systems cannot be applied to natural samples. For calculation of residence times or cooling rates the present Ni data yield shorter timescales compared to those obtained using diffusion data published until now.In addition to Ni diffusion coefficients, Fe-Mg, Mn and Ca diffusion data were obtained from some of the same diffusion couples (Fo₉₀-Fo₁₀₀). It is found that the activation energies, E_D[Ni] ≅ E_D[Fe-Mg] ≅ E_D[Mn] ≤ E_D[Ca]. All diffusion coefficients are strongly dependent on the major element composition of olivine.     

Estimation of the Al,Si distribution of feldspars from the lattice translations Tr[110] and Tr[110]

A method is proposed to estimate the Al,Si distribution of alkali feldspars from two lattice translations, called Tr[110] and Tr[1¯10], which are the repeat distances in the [110] and [1¯10] directions. The Al content t₁0 of the T₁0 tetrahedral site is estimated from Tr[1¯10], whereas Tr[110] measures t₁m, the Al content of the T₁m site. In order to simplify the estimation procedure, the line separation =2 (131)-2 (1¯31) is given as a function of t₁0 and t₁0-t₁m.     

Die Trocknung des Klärschlammes durch Verdunstung

Zusammenfassung Es werden Bau und Bemessung der Beete, sowie die bisherigen Forschungsarbeiten beschrieben, insbesondere die Verdunstungs- und Trocknungsvorg?nge. Eingehende Versuche über die natürliche Trocknung des Schlammes durch Verdunstung im Freien sind durchgeführt worden. Es werden Formeln für Trocknungsdauer und Beetbelastung entwickelt und einige Vorschl?ge für die Praxis angegeben.

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Summary The dimensioning and construction of drying beds are described, as is previous research, in particular the evaporation and drying processes. Detailed studies on the natural thermal drying of sludge through evaporation in the open air were carried out. Formulas for the drying period and bedloading were developed and several suggestions for the practice are given.

     

Quasi-static poroelastic parameters in rock and their geophysical applications

The constitutive equations of poroelasticity contain four static moduli. Different sets of moduli are reviewed in the context of their laboratry measurement and their geophysical applications. One complete set consits of the drained bulk modulus and Poisson's ratio, and their undrained counterparts. Skempton's coefficient (ratio of pore pressure increment to mean stress increment under undrained conditions) and the Biot-Willis parameter serve equally well for the undrained bulk modulus and Poisson's ratio, because they permit the drained and undrained moduli to be related to each other. Time dependence is introduced into poroelastic behavior through Darcy's law. Geophysical applications that can be approximated by undrained conditions (fast loading) include seismicity, tidal and barometric loading, and tectonic compression. Several of these problems are most directly formulated in terms of Skempton's coefficient, undrained Poisson's ratio, and hydraulic diffusivity.     

A Review to Develop new Correlations for Geotechnical Properties of Organic Soils

Geotechnical and Geological Engineering - Organic soils are considered one of the most problematic soils due to their high compressibility and low shear strength at small strains. Characterizing...