The use of 18O/16O ratios to study the formation and chemical origin of coal

The ${}^{18}\text{O}{}^{16}\text{O}$ ratios of some New Zealand peat, lignite and coal samples were measured and compared with those of various coal precursors (cellulose, lignin and plant resins). The results showed that the major source of oxygen in all cases (except that of high rank coal) was from cellulose with the contribution from lignin and plant resins being insignificant.     

On the determination of the diffusion coefficient of heterogeneous aerosols by the dynamic method

Summary It is shown that the marked influence of the air-flow on the value of the diffusion coefficient as determined by the dynamic method can be fully explained when heterogeneity of the condensation nuclei in the aerosol is assumed. A theory of the dynamic method for heterogeneous aerosols is given on the assumption that the diffusion loss of a mixture of condensation nuclei of different diffusion coefficients is the sum of the diffusion losse of its components. Procedures for resolving heterogeneous aerosols into their components using the dynamic method are developed. The accuracy attainable by one of the methods which requires no assumptions on the number of components in the aerosol under investigation is illustrated by a numerical example.

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Zusammenfassung Es wird gezeigt, dass der bemerkenswerte Einfluss der Luftstromgeschwindigkeit auf die Grösse des mit der dynamischen Methode bestimmten Diffusionskoeffizienten völlig erklärt werden kann, wenn Heterogenität der Kondensationskerne im Aerosol angenommen wird. Eine Theorie der dynamischen Methode für heterogene Aerosole wird unter der Annahme, dass der Diffusionsverlust eines Gemisches von Kondensationskernen mit verschiedenen Diffusionskoeffizienten gleich der Summe der Diffusionsverluste ihrer Komponenten ist, gegeben. Verfahren der Zerlegung heterogener Aerosole in ihre Komponenten mittels der dynamischen Methode werden entwickelt. Die mit einem der Verfahren, welches keine Annahme über die Zahl der in dem zu untersuchenden Aerosol vorhandenen Komponenten benötigt, erreichbare Genauigkeit wird an einem numerischen Beispiel illustriert.

     

The Strel’tsovka uranium district: Isotopic geochronological (U-Pb,Rb-Sr,Sm-Nd) characterization of granitoids and their place in the formation history of uranium deposits

An isotopic geochronological study of Russia’s largest Strel’tsovka uranium district has been carried out. Polychronous granite generation, which determined the structure of the pre-Mesozoic basement, had important implications for the formation of volcanotectonic structural elements bearing economic uranium mineralization. The study of U-Pb, Rb-Sr, and Sm-Nd isotopic systems of whole-rock samples and minerals of granitic rocks allowed us to estimate the deportment of these systems in spatially conjugated granite-forming and hydrothermal processes differing in age and gave grounds for revising the age of granites pertaining to the Urulyungui Complex and refining the age of the Unda Complex.     

The alignment of clusters using large-scale simulations

The alignment of clusters of galaxies with their nearest neighbours and between clusters within a supercluster is investigated using simulations of 512³ dark matter particles for ΛCDM and τ CDM cosmological models. Strongly significant alignments are found for separations of up to 15  h ⁻¹ Mpc in both cosmologies, but for the ΛCDM model the alignments extend up to separations of 30  h ⁻¹ Mpc. The effect is strongest for nearest neighbours, but is not significant enough to be useful as an observational discriminant between cosmologies. As a check of whether this difference in alignments is present in other cosmologies, smaller simulations with 256³ particles are investigated for four different cosmological models. Because of poor number statistics, only the standard CDM model shows indications of having different alignments from the other models.     

The shallow water equations on the sphere and their Lagrange-Galerkin-solution

Summary ?The shallow water equations are formulated on the sphere in a three-dimensional coordinate system with the aid of tangential velocity components and differential operators. We introduce a modified semi-Lagrangian scheme for the discretization in time. The discretization in space is solved by linear finite elements. The grids we use are regular refinements of a macro triangulation which itself is derived from a highly symmetric polyeder also known as a bucky or soccer ball. The good numerical results show that this combination is a promising approach. The numerical algorithm is stable and its strength is the conservation of mass and energy. Received April 13, 2001; Revised December 18, 2001     

Vibrationally excited molecular hydrogen in circumstellar clouds and the interstellar CH+ abundance

The production of CH⁺ in dense interstellar clouds under intense UV irradiation is discussed. A model applicable to the cloud towards the star 20 Tau is described.     

Aklimaite, Ca4[Si2O5(OH)2](OH)4 · 5H2O, a new natural hydrosilicate from Mount Lakargi, the Northern Caucasus, Russia

A new mineral aklimaite, Ca₄[Si₂O₅(OH)₂](OH)₄ · 5H₂O, has been found near Mount Lakargi, Upper Chegem caldera, Kabardino-Balkaria, the Northern Caucasus, Russia, in the skarnified limestone xenolith in ignimbrite. This hydrothermal mineral occurs in a cavity of altered larnite skarn and is associated with larnite, calcium humite-group members, hydrogarnets, bultfonteinite, afwillite, and ettringite. Aklimaite forms transparent, colorless (or occasionally with pinkish tint) columnar or lath-shaped crystals up 3 × 0.1 × 0.01 mm in size, flattened on {001} and elongated along {010}; they are combined in spherulites. The luster is vitreous; the cleavage parallel to the {001} is perfect. D _calc = 2.274 g/cm³. The Mohs’ hardness is 3–4. Aklimaite is optically biaxial, negative, 2V _meas > 70°, 2V _calc = 78°, α = 1.548(2), β = 1.551(3), γ = 1.553(2). The IR and Raman spectra are given. The chemical composition (wt %, electron microprobe) is as follows: 0.06 Na₂O, 0.02 K₂O, 45.39 CaO, 0.01 MnO, 0.02 FeO, 24.23 SiO₂, 0.04 SO₃, 3.22 F, 27.40 H₂O_(calc.), ?1.36 -O=F₂; the total is 99.03. The empirical formula calculated on the basis of 2Si apfu with O + OH + F = 16 is as follows: (Ca_4.02Na_0.01)_Σ4.03[Si_2.00O_5.07(OH)_1.93][(OH)_3.16F_0.84] _Σ4.00 · 5H₂O. The mineral is monoclinic, space group C2/m, a = 16.907(5), b = 3.6528(8), c = 13.068(4) Å, β = 117.25(4)·, V= 717.5(4) ų, Z = 2. Aklimaite is representative of the new structural type, the sorosilicate with disilicate groups [Si₂O₅(OH)₂]. The strongest reflections in the X-ray powder patterns [d, Å (hkl)] are: 11.64(100)(001), 2.948(32)(310, 203), 3.073(20) ( $\bar 404$ , $\bar 311$ ), 2.320(12)(005, 510), 2.901 (11)(004), 8.30(10) $\left( {\bar 201} \right)$ . The type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.     

Lagrangian measurements and modelling of fluid advection in the inner surf and swash zones

New laboratory and field data are presented on fluid advection into the swash zone. The data illustrate the region of the inner surf zone from which sediment can be directly advected into the swash zone during a single uprush, which is termed the advection length. Experiments were conducted by particle tracking in a Lagrangian reference frame, and were performed for monochromatic breaking waves, solitary bores, non-breaking solitary waves and field conditions. The advection length is normalised by the run-up length to give an advection ratio, A, and different advection ratios are identified on the basis of the experimental data. The data show that fluid enters the swash zone from a region of the inner surf zone that can extend a distance seaward of the bore collapse location that is approximately equal to half of the run-up length. This region is about eight times wider than the region predicted by the classical swash solution of Shen and Meyer [Shen, M.C., Meyer, R.E., 1963. Climb of a bore on a beach. Part 3. Runup. Journal of Fluid Mechanics 16, 113–125], as illustrated by Pritchard and Hogg [Pritchard, D., Hogg, A.J., 2005. On the transport of suspended sediment by a swash event on a plane beach. Coastal Engineering 52, 1–23]. Measured advection ratios for periodic waves show no significant trend with Iribarren number, consistent with self-similarity in typical swash flows. The data are compared to recent characteristic solutions of the non-linear shallow water wave (NLSW) equations and both finite difference and finite volume solutions of the NLSW equations.     

Incrustations and fumarolic condensates at kilauea volcano, Hawaii: field, drill-hole and laboratory observations

Hawaiian volcanoes characteristically have but few of the many types of minerals found in incrustations of other volcanic areas. In Hawaii sulfates resulting from air oxidation of volatiles predominate, and fluorides produced during rock alteration by fumarolic gases are prominent. Halides are generally found where reducing conditions exist in fumaroles and lava lake drill holes. The most common mineral types are sulfur, opaline silica, gypsum, ralstonite, and thenardite. Minerals from the same deposit are found to vary markedly in the content of the less abundant components. Condensates from vapor issuing from fumaroles show little quantitative relationship in component content to incrustations deposited at the same fumaroles. It is believed that an energetically favorable isomorphic substitution of some elements in the crystal lattice of a depositing mineral may lead to the build-up of a high concentration of an element from a lean vapor. Equilibrium calculations applied to condensate studies give a good quantitative approximation to the concentrations of the elements found in natural systems, but when applied to incrustations they serve only to indicate general compositional relations. Laboratory studies have shown the important role of chlorides in metal transfer in the gas phase in high-temperature aqueous systems, but only in the absence of oxygen. These studies also demonstrated the important role of HF in rock alteration and in the transfer of silica.     

Variations in statistical parameters of the <Emphasis Type="Italic">NmF</Emphasis>2 winter anomaly with latitude and solar activity

The maximal R ratios of the winter-to-summer NmF2 values of each ionosonde are calculated for a specified UT under daytime quiet geomagnetic conditions and at approximately equal levels of solar activity, based on foF2 measurement data of 98 ionosondes at mid- and low geomagnetic latitudes of the Northern and Southern hemispheres for 1957–2009. The P(R > 1) conditional probability of NmF2 winter anomaly observations, as well as the most probable RMP and average <R> of R values are calculated for low, moderate, and high solar activity on the base of foF2 measurements during the periods December 22 ± 30 days and June 21 ± 30 days. Variations in P(R > 1), RMP, and 〈R〉 with latitude and solar activity are analyzed.