A New Algorithm for Wind-Vector Retrieval From Scatterometers

A new efficient algorithm for retrieving wind-vector solutions from scatterometers is developed based on a criterion of minimum normalized standard deviation (NSD) of wind speed derived from backscatter measurements using a geophysical model function (GMF). Its performance has been evaluated through simulations using QSCAT-1 GMF and the QuikSCAT observational geometry. The present algorithm, named the NSD algorithm, is found to be computationally more efficient (two to three times) besides being at par with the maximum-likelihood estimator (MLE) algorithm in terms of retrieval skill, retrieval errors, and distribution of solutions, on the basis of simulations as well as comparison of limited QuikSCAT-data-derived winds with National Centers for Environmental Prediction and European Centre for Medium-Range Weather Forecasts model winds. Simulation results and analysis of sample QuikSCAT data are presented.      

Ability of indigenous Bacillus licheniformis and Bacillus subtilis in microbial enhanced oil recovery

Microbially produced lipopeptide have been isolated and studied for microbial enhanced oil recovery. About 60 gram positive bacteria isolated from soil contaminated with crude oil, near the crude oil storage tank in Tehran Refinery, Tehran, Iran. However, most of these studies have produced lipopeptide by one of the pure-culture microbes isolated in a laboratory. Among the isolates, heamolytic tests revealed two biosurfactant producers. The isolated strains were designated as C2, E1. By using morphological, biochemical and molecular biology tests (16 SrRNA), the strains identified as Bacillus licheniformis and Bacillus subtitlis, respectively. Emulsification activity and measurement of surface tension indicated that, the isolates were high producers of biosurfactant. The product of C2 and E1 is mainly lipopeptide. This product reduce surface tension from 65 to 30 mN/m. Emulsified activity of crude oil was 92% for C2 and 90 % in case of E1. This is the first report of indigenous Bacillus licheniformis and Bacillus subtilis from a soil contaminated with oil in an Iranian refinery with ability to produce biosurfactant.     

Influence of biotic-abiotic factors on the degradation of novaluron in tropical soil

In this study, the degradation of novaluron (benzoylphenyl urea insect growth regulator) was investigated under controlled laboratory conditions in clay loam alluvial and coastal saline soils of West Bengal, India. The application rates were field rate (FR); 2FR and 10FR. The incubation study was carried out at 30 °C and 60% of maximum water holding capacity of both the soils. Degradation of novaluron in both the soils followed first order reaction kinetics at all application rates under non-sterile and sterile conditions. The half-lives of novaluron in non-sterilized soils ranged from 17.0–17.8 days (alluvial soil) and 11.4–12.7 days (coastal saline soil), while the values in case of the sterilized soils were 53.7–59.0 days (alluvial soil) and 28.9–29.8 days (coastal saline soil) respectively. The novaluron degradation patterns were found to be highly influenced by soil types, application rates, and biotic abiotic factors. Abiotic factors strongly influenced novaluron degradation in both the soils. Biotic degradation was higher in alluvial soil compared to the coastal saline soil.     

Modeling study of the effects of the coagulation kernel with van der Waals forces and turbulence on the particle size distribution

In this study, variations in the size distributions due to different assumptions for the coagulation kernel are investigated. In order to evaluate how the coagulation kernel influences the form of the particle size distribution and to describe the process of the Brownian coagulation, the Brownian coagulation kernel, including the van der Waals forces, is compared with the most frequently used coagulation coefficients. Retardation should be considered for interparticle interactions for particles larger than 1μm radius. However, for particle sizes larger than 0.1 μm, the Brownian kernel is not dominant, so the retardation effect can be ignored. The inclusion of the van der Waals forces in the Brownian coagulation kernel caused a faster coagulation process in the small particle size range. Taking account of the turbulent coagulation kernel, the turbulent coagulation kernel becomes more important when the turbulent intensity is higher. The turbulent coagulation kernel affects the large particle size range and ignoring the turbulent coagulation kernel will lead to overestimation of particle number concentration in model simulation. The results of this study indicate that the inclusion of van der Waals forces or the turbulent coagulation kernel in the total coagulation kernel impacts on the modeled particle size distributions and total particle number concentration.     

Paleomagnetic studies of the Late Mesozoic deformation stage in the southern Primorye region

The analysis of paleomagnetic data available for the southern Primiorye region revealed that the studied objects were magnetized under regional remagnetization presumably during the Late Mesozoic folding and this magnetization can be interpreted as being synfolding. The interpretation is based on the parameter that characterizes the folding completion degree immediately before regional remagnetization. It is shown that the relaxation of Late Mesozoic horizontal stresses was irregular. The obtained estimates of the degree of folding completion are consistent with the available geological data and Talitskii’s model for tectonic deformations.     

Automated Kerogen Classification in Microscope Images of Dispersed Kerogen Preparation

We develop the classification part of a system that analyses transmitted light microscope images of dispersed kerogen preparation. The system automatically extracts kerogen pieces from the image and labels each piece as either inertinite or vitrinite. The image pre-processing analysis consists of background removal, identification of kerogen material, object segmentation, object extraction (individual images of pieces of kerogen) and feature calculation for each object. An expert palynologist was asked to label the objects into categories inertinite and vitrinite, which provided the ground truth for the classification experiment. Ten state-of-the-art classifiers and classifier ensembles were compared: Naïve Bayes, decision tree, nearest neighbour, the logistic classifier, multilayered perceptron (MLP), support vector machines (SVM), AdaBoost, Bagging, LogitBoost and Random Forest. The logistic classifier was singled out as the most accurate classifier, with an accuracy greater than 90. Using a 10 times 10-fold cross-validation provided within the Weka software, we found that the logistic classifier was significantly better than five classifiers (p<0.05) and indistinguishable from the other four classifiers. The initial set of 32 features was subsequently reduced to 6 features without compromising the classification accuracy. A further evaluation of the system alerted us to the possible sensitivity of the classification to the ground truth that might vary from one human expert to another. The analysis also revealed that the logistic classifier made most of the correct classifications with a high certainty.     

Upper Cretaceous carbonate hosted zinc–lead–barite deposits in Northern Thrust Zone, northern Iraq: petrography and geochemistry

Zinc–lead–barite deposits located in Lefan and Lower Banik localities of about 25 km northeast of Zakho City, Northern Iraq consist of a group of strata-bound sulfides hosted in Upper Cretaceous (Upper Campanian–Maastrichtian) dolomitic limestone. Carbonate-hosted ores contain 3.77% Zn, 2% Pb, and 5% Fe, while in lower Banik, they contain 1.5% Zn, 0.37% Pb, and 1.4% Fe. Diagenetic processes, such as dolomitization and recrystalization in addition to the type of microfacies, provided appropriate physical and chemical conditions that permitted the passage of ore-bearing fluids and participated in precipitation and ore localization. These deposits are precipitated in a platform and developed within the Foreland Thrust Belt. Ore precipitated as infill of intergranular dolomite porosity with replaced dolomite and rudist shells forming disseminated crystals that occupy intergranular pore spaces around dolomite and calcite and as infill of dissolution spaces and fractures.     

Petrogenesis of the late-Delamerian gabbroic complex at Black Hill,South Australia: Implications for convective thinning of the lithospheric mantle

Summary A group of funnel-shaped gabbroic plutons at Black Hill, South Australia, consist of a lower series of layered peridotite, troctolite and olivine gabbro cumulates overlain by gabbronorites and potassic gabbronorites, the latter yielding a Sm-Nd isochron of 489 ± 39 Ma. Mineral assemblages in the gabbros record an olivine compositional hiatus (Fo_75-55) and a high temperature (1200-1000°C), low pressure (1 kbar), continental tholeiitic fractionation trend under moderate f_{O 2} (QFM) conditions. The liquid line of descent involved complex open system processes including recharge and crustal assimilation. In one pluton, fine-grained norites may reflect assimilation which resulted in an increaseda _SiO2 ^liquid causing orthopyroxene to crystallize prior to plagioclase.All the gabbros, including the most primitive peridotites, are LREE and incompatible element enriched. Moreover, the calculated parental magma composition in equilibrium with the most primitive troctolite has high La/Yb, La/Nb, Ti/Y and low Rb/Ba, similar to that of basaltic dykes which cut the gabbroic complex. Such compositions are untypical of melts derived from the asthenosphere suggesting that the incompatible element enrichment is not simply due to small degrees of melting. Given the isotopic constraints (Nd_i 3.4 to –4.6,⁸⁷Sr/⁸⁶Sr_i 0.7038-0.7065), this enrichment is not easily reconciled by crustal contamination either, and instead it is inferred to reflect an enriched lithospheric mantle source. Published data on mantle xenoliths from local Tertiary volcanoes overlap the isotopic and geochemical array of the gabbros and dykes, supporting this hypothesis.In conjunction with A-type granites and minor volcanic rocks, the gabbroic plutons form part of a high temperature, bimodal magmatic suite which intruded the Adelaide fold belt just after the cessation of convergent deformation during the Cambro-Ordovician Delamerian Orogeny. The appearance of such magmas is problematic since thick orogenic lithosphere severely restricts the likelihood of decompression melting in the asthenosphere. One solution to this dilemma is that convective thinning of the lithospheric mantle beneath the orogen promoted melting of hydrated, enriched regions within the lithospheric mantle. Such a model can reconcile the strong lithospheric mantle signature in the gabbros with the observation that their intrusion was coincident with uplift and the cessation of deformation.

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Die Petrogenese eines spätdelamerischen Gabbrokomplexes von Black Hill, Südaustralien: Schlußfolgerungen zur konvektiven Ausdünnung des lithospharischen Mantels

Zusammenfassung Eine Gruppe von trichterförmigen, gabbroiden Plutonen von Black Hill, Südaustralien, setzt sich aus einer unteren Serie von geschichteten Peridotiten, Troktoliten and Olivin-Gabbro-Kumulaten, die von Gabbro-Noriten und potassischen Gabbros überlagert werden, zusammen; letzgenannte Gesteine ergaben ein Sm-Nd Isochronenalter von 489 ± 39 Ma. Die Mineralzusammensetzungen der Gabbros belegen eine Mischungslücke bei Olivin (Fo_75-55). Die Gesteine folgen einem kontinentalen, tholeiitischen Fraktionierungstrend und kristallisierten bei hohen Temperaturen (1200-1000°C), unter niedrigem Druck ( 1 kbar) and moderatem fo₂ ( QFM). Wiederholte Magmenzufuhr und Krustenassimilation sind weitere zu beriicksichtigende, komplexe Prozesse, die sich in einem offenen System abspielten. Feinkörnige Norite von einem der Plutone könnten durch Assimilationsprozesse - she äußern sich in einer Erhöhung desa _SiO₂ ^liquid liquid - entstanden sein. In diesen Gesteinen kristallisierte Orthopyroxen vor Plagioklas.Alle Gabbros, einschließich der primitivsten Peridotite, sind an LREE und inkompatiblen Elementen angereichert. Die berechnete Zusammensetzung des Ausgangsmagmas, das im Gleichgewicht mit dem primitivsten Troktolit steht, weist hohe La/Yb, La/Nb, Ti/Y and niedrige Rb/Ba auf. Basaltische Dykes, die die Gabbros durchsetzen zeigen ähnliche Elementverhältnisse. Derartige Zusammensetzungen sind untypisch für astenosphärische Schmelzen und belegen, daß die Anreicherung an inkompatiblen Elementen nicht einfach nur mit geringen Aufschmelzungsraten zu erklären ist. Auf Grund der Isotopendaten (Nd_i 3.4 to -4.6,⁸⁷Sr/⁸⁶ Sr_i 0.7038–0.7065) kann these Anreicherung auch nicht leicht mit Krustenkontamination erklärt werden. Vielmehr wird eine angereicherte, lithosphärische Mantelquelle vermutet. Publizierte Daten an Mantelxenolithen von tertiären Vulkanen zeigen sehr ähnliche isotopische und geochemische Zusammensetzungen and belegen these Hypothese.Gemeinsam mit A-Typ Graniten und untergeordnet, vorkommenden, vulkanischen Gesteinen sind die Gabbros Teil einer hochtemperierten bimodalen, magmatischen Serie, die den Adelaide Fold Belt postdeformativ, während der kambro-ordovizischen delamerischen Orogenese, intrudierten. Das Vorkommen solcher Magmen ist problematisch, da die Präsenz dicker, orogen gebildeter Lithosphäre die Möglichkeit der Dekompressions-Aufschmelzung der Astenosphäre stark vermindert. Eine mögliche Lösung dieses Dilemmas ist, daß konvektives Ausdünnen des lithosphärischen Mantels unterhalb der Orogenzone das Aufschmelzen von hydratisierten, angereicherten Regionen innerhalb der Lithosphäre förderte. Dieses Modell bringt die Beobachtungen, daß die Gabbros einerseits eine lithosphärische Signatur zeigen, andererseits aber während der Hebungsphase und am Ende des Deformationsgeschehens intrudierten, in Einklang.

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With 15 Figures     

Detection of a new interstellar molecular ion, H2COH+ (protonated formaldehyde)

A new interstellar molecular ion, H2COH+ (protonated formaldehyde), has been detected toward Sgr B2, Orion KL, W51, and possibly in NGC 7538 and DR21(OH). Six transitions were detected in Sgr B2(M). The 1(1,0)-1(0,1) transition was detected in all sources listed above. Searches were also made toward the cold, dark clouds TMC-1 and L134N, Orion (3N, 1E), and a red giant, IRC + 10216, without success. The excitation temperatures of H2COH+ are calculated to be 60-110 K, and the column densities are on the order of 10(12)-10(14) cm-2 in Sgr B2, Orion KL, and W51. The fractional abundance of H2COH+ is on the order of 10(-11) to 10-(9), and the ratio of H2COH+ to H2CO is in the range 0.001-0.5 in these objects. The values in Orion KL seem to be consistent with the "early time" values of recent model calculations by Lee, Bettens, & Herbst, but they appear to be higher than the model values in Sgr B2 and W51 even if we take the large uncertainties of column densities of H2CO into account. We suggest production routes starting from CH3OH may play an important role in the formation of H2COH+.     

On the magnetism of stars and planets

A self-consistent statistical approach to the problem of planetary and stellar magnetism is suggested. The mechanism of magnetic field generation in the astronomical objects, where the existence of fields is associated with the axial rotation of objects, is discussed. In the general case the light pressure, the centrifugal, gravitational and other forces produce partial -separation of the charges. As a result of the system rotation, the magnetic fields of the currents of these charges are not compensated. The influence of various factors on the magnetic field of some object is analysed.