Geosynthesis of dibenzothiophene and alkyl dibenzothiophenes in crude oils and sediments by carbon catalysis

Sediment extracts and crude oils have been shown to contain methyl substituted biphenyls and dibenzothiophenes, with isomer distributions suggesting a geochemical relationship between the two compound classes. Laboratory simulation experiments have shown that carbon catalyses the reaction between surface adsorbed sulfur and biphenyl to form dibenzothiophene. Similarly, the methyl substituted biphenyls reacted to yield corresponding methyl dibenzothiophenes. We suggest that the widespread distribution of dibenzothiophene and alkylated dibenzothiophenes in sediments and crude oils is the result of a catalytic reaction of biphenyl ring systems and surface-adsorbed sulfur on the surface of carbonaceous material.     

Flood hazard assessment and mapping of River Swat using HEC-RAS 2D model and high-resolution 12-m TanDEM-X DEM (WorldDEM)

Natural Hazards - Floods are among the most devastating and recurring natural hazards and have caused extensive economic losses to human lives and infrastructures around the world. Swat valley in...     

Number Counts,Confusion, Mapping Issues,and Sky Coverage Analysis for Radio Continuum Surveys through Emu Early Science,EMU-ASKAP,and WODAN Especially for Cosmology Science Goals

In this study, we discuss the challenges radio astronomers face while observing radio continuum sources. We consider issues related to rms noise, confusion, position accuracy, shot noise and how these issues affect observation results, data analysis and the science goals we are trying to achieve. We mainly focus on the Evolutionary Map of the Universe (EMU-ASKAP) sky survey, EMU Early science survey and Westerbork Observations of the Deep APERTIF Northern sky (WODAN). The study will also be useful for future surveys like with possible continuum surveys through MeerKAT (e.g., MIGHTEE) and SKA-1. The late time Integrated Sachs-Wolfe (ISW) effect detection is one of the major areas of research related to dark energy cosmology. We will particularly discuss how technical, data analysis and mapping issues, affect galaxy over/under density dependent science goals like the detection of the late time Integrated Sachs-Wolfe (ISW) effect through wide-field radio continuum surveys.

     

Geological and Geochemical Characteristics of Gold Mineralization in the Salu Bulo Prospect,Sulawesi, Indonesia

The Salu Bulo prospect is one of the gold prospects in the Awak Mas project in the central part of the western province, Sulawesi, Indonesia. The gold mineralization is hosted by the meta‐sedimentary rocks intercalated with the meta‐volcanic and volcaniclastic rocks of the Latimojong Metamorphic Complex. The ores are approximately three meters thick, consisting of veins, stockwork, and breccias. The veins can be classified into three stages, namely, early, main, and late stages, and gold mineralization is related to the main stage. The mineral assemblage of the matrix of breccia and the veins are both composed of quartz, carbonate (mainly ankerite), and albite. High‐grade gold ores in the Salu Bulo prospect are accompanied by intense alteration, such as carbonatization, albitization, silicification, and sulfidation along the main stage veins and breccia. Alteration mineral assemblage includes ankerite ± calcite, quartz, albite, and pyrite along with minor sericite. Pyrite is the most abundant sulfide mineral that is spatially related to native gold and electrum (<2–42 μm in size). It is more abundant as dissemination in the altered host rocks than those in veins. This suggests that water–rock interaction played a role to precipitate pyrite and Au in the Salu Bulo prospect. The Au contents of intensely altered host rocks and ores have positive correlations with Ag, Ni, Mo, and Na. Fluid inclusions in the veins of the main stage and the matrix of breccia are mainly two‐phase liquid‐rich inclusions with minor two‐phase, vapor‐rich, and single‐phase liquid or vapor inclusions. CO₂ and N₂ gases are detected in the fluid inclusions by Laser Raman microspectrometry. Fluid boiling probably occurred when the fluid was trapped at approximately 120–190 m below the paleo water table. δ¹⁸O_SMOW values of fluid, +5.8 and +7.6‰, calculated from δ¹⁸O_SMOW of quartz from the main stage vein indicate oxygen isotopic exchange with wall rocks during deep circulation. δ³⁴S_CDT of pyrite narrowly ranges from ?2.0 to +3.4‰, suggesting a single source of sulfur. Gold mineralization in the Salu Bulo prospect occurred in an epithermal condition, after the metamorphism of the host rocks. It formed at a relatively shallow depth from fluids with low to moderate salinity (3.0–8.5 wt% NaCl equiv.). The temperature and pressure of ore formation range from 190 to 210°C and 1.2 to 1.9 MPa, respectively.     

An estimation of the height system bias parameter <Emphasis Type="Italic">N</Emphasis><Subscript>0</Subscript> using least squares collocation from observed gravity and GPS-levelling data

This paper deals with the analysis of gravity anomaly and precise levelling in conjunction with GPS-Levelling data for the computation of a gravimetric geoid and an estimate of the height system bias parameter N_o for the vertical datum in Pakistan by means of least squares collocation technique. The long term objective is to obtain a regional geoid (or quasi-geoid) modeling using a combination of local data with a high degree and order Earth gravity model (EGM) and to determine a bias (if there is one) with respect to a global mean sea surface. An application of collocation with the optimal covariance parameters has facilitated to achieve gravimetric height anomalies in a global geocentric datum. Residual terrain modeling (RTM) technique has been used in combination with the EGM96 for the reduction and smoothing of the gravity data. A value for the bias parameter N_o has been estimated with reference to the local GPS-Levelling datum that appears to be 0.705 m with 0.07 m mean square error. The gravimetric height anomalies were compared with height anomalies obtained from GPS-Levelling stations using least square collocation with and without bias adjustment. The bias adjustment minimizes the difference between the gravimetric height anomalies with respect to residual GPS-Levelling data and the standard deviation of the differences drops from 35 cm to 2.6 cm. The results of this study suggest that N_o adjustment may be a good alternative for the fitting of the final gravimetric geoid as is generally done when using FFT methods.     

Effects of layered heterogeneity in subsurface geologic materials on solute transport under field conditions: A case study from northeastern Iowa, USA

In the Cedar River watershed of northeastern Iowa, USA, water quality in 17 out of 20 private wells indicates that groundwater is contaminated with nitrate from agricultural leachates. In nine of the wells, nitrate concentration exceeds the US Environmental Protection Agency recommended maximum contaminant level (MCL) of 45umg/L (as NO3 ^m) for drinking purposes. Solute-transport investigations determined that the surficial loam sediments, the Quaternary sand and gravel deposits, and the glacial till deposits form layered heterogeneity in the subsurface. The resulting conductivity contrast causes a capillary barrier, thereby altering the mechanisms of vertical tracer movement. Storm-water tracing with potassium bromide, corn fertilizer, and fluorescein dye indicates that macropore flow occurs only within the upper 0.9um of loamy sediments. An average breakthrough concentration of 204umg/L bromide at 0.3um depth on day 3 after the storm event supports the hypothesis of macropore flow in the surficial soils. Fluorescein dye was recovered at a depth of 0.3um with a peak concentration of 650u7g/L at approximately 5udays after the storm event. The loamy sediment layer is underlain by the Iowan Pebble Band, a pebbly layer admixed with sand, developed in post-glacial time. In the field experiments, preferential flow of the tracers was predominantly vertical within the loamy sediments but rapidly changed to a horizontal matrix flow upon entering the materials of higher saturated hydraulic conductivity in the Pebble Band. The Pebble Band is underlain by low-conductivity deposits of pre-Illinoian till. Even though the upper oxidized portion of the glacial till is reported to have macropores, the Pebble Band prevented deeper infiltration of storm water by maintaining a strong component of horizontal hydraulic gradient. Chemical data indicate that the Pebble Band is a hydraulic-conductivity boundary that abruptly changes the unsaturated-flow mechanism from macropore flow to matrix flow. Résumé Dans le bassin de la rivière du Cèdre, au nord-est de l'Iowa (États-Unis), la qualité de l'eau de 17 puits particuliers sur 20 montre que l'eau souterraine est contaminée par des nitrates provenant de lessivages agricoles. Dans 9 de ces puits, la concentration en nitrates dépasse la concentration maximale recommandée par l'Agence américaine de protection de l'environnement (EPA), fixée à 45umguNO3/L pour l'eau potable. Des études sur le transport de solutés ont montré que les sédiments détritiques (loamy) superficiels, les dépôts quaternaires de sables et de graviers et les dépôts morainiques constituent une formation hétérogène litée sous la surface. Le contraste de conductivité résultant constitue une barrière capillaire qui modifie les mécanismes réglant le mouvement vertical du traceur. Le traçage de l'eau d'une averse par du bromure de potassium, un engrais du maïs et de la fluorescéine indique que l'écoulement dans les macropores se produit uniquement dans les premiers 90ucm des sédiments détritiques (loamy). Une concentration moyenne de la restitution de 204umg/L de bromure à 30ucm de profondeur le troisième jour après l'averse va dans le sens de l'hypothèse d'un écoulement dans les macropores des sols superficiels. La restitution de la fluorescéine s'est produite à 30ucm de profondeur par un pic à une concentration de 650u7g/L environ 5ujours après l'averse. La couche de sédiments détritiques est recouverte par la couche de galets de l'Iowa, un niveau postglaciaire de galets mêlés à du sable. Au cours des expériences de terrain, un écoulement préférentiel des traceurs a été verticalement prédominant dans les sédiments détritiques (loamy), mais s'est rapidement changé en un écoulement matriciel horizontal en entrant dans les matériaux à plus forte conductivité hydraulique saturée dans la couche de galets de l'Iowa. Cette couche de galets est recouverte (underlain) par des dépôts à faible conductivité de la moraine pré-illinoyenne. Même si la partie supérieure oxydée de la moraine paraît posséder des macropores, la couche à galets empêche l'infiltration de l'eau de l'averse en introduisant une forte composante dans le gradient hydraulique horizontal. Les données chimiques montrent que la couche à galets se présente comme une limite de conductivité hydraulique qui change brutalement le mécanisme d'écoulement non saturé d'un écoulement en macropore en un écoulement matriciel. Resumen Se ha detectado una contaminación por lixiviados de nitrato de origen agrícola en 17 de los 20 pozos particulares muestreados en la cuenca del río Cedar, al Nordeste de Iowa (EEUU). En nueve de los pozos, el contenido en nitrato es superior a la concentración máxima admitida para agua potable (45umg/L), de acuerdo con los criterios de la Agencia Medioambiental de los Estados Unidos (USEPA). Mediante investigaciones de transporte de solutos, se ha podido caracterizar la heterogeneidad del subsuelo debido al contraste de conductividad hidráulica entre las tres capas identificadas: sedimentos margosos superficiales, depósitos Cuaternarios de arena y grava, y depósitos de till glacial. El contraste de materiales origina una barrera capilar que altera los mecanismos del desplazamiento vertical de trazador. Se ha utilizado bromuro de potasio, fertilizante de maíz y fluoresceína como trazadores del agua de tormenta. De esta forma se ha observado que el flujo a través de macroporos es significativo únicamente en la capa superior margosa de 0.9um. Prueba de ello es que se registró una concentración promedio de 204umg/L de bromuro, a una profundidad de 0.3um, tres días después del episodio de lluvia. Se midió asimismo un pico de fluoresceína de 650u7g/L, también a 0.3um, al cabo de cinco días. Bajo las margas se encuentra el nivel de cantos rodados de Iowa (Iowan Pebble Band), desarrollado en un período post-glacial, que consiste en cantos rodados mezclados con arena. Gracias a los experimentos de campo se pudo comprobar que hay un flujo vertical preferente de trazador en el estrato superior margoso, el cual se convierte de inmediato en horizontal (en la matriz) al encontrar el nivel de cantos rodados, cuya conductividad hidráulica saturada es mayor. Por debajo de los cantos hay depósitos de tillita pre-Illinoiense de baja conductividad. Aunque se han identificado macroporos en la parte superior oxidada de los depósitos glaciales, la existencia de un marcado gradiente horizontal en el nivel de cantos rodados actúa impidiendo la infiltración del agua de tormenta. Los datos químicos indican que el nivel de cantos rodados se comporta como un contorno de conductividad hidráulica que altera abruptamente el mecanismo de flujo no saturado, inicialmente a través de los macroporos del suelo, para convertirlo en flujo en medio poroso.     

中国-巴基斯坦喀喇昆仑公路Ghulkin冰川百年进退变化

巴基斯坦喀喇昆仑山的Ghulkin冰川是距离中国-巴基斯坦喀喇昆仑公路最近的典型冰川之一,其冰川的进退变化影响着喀喇昆仑公路改建工程的线路设计与工程施工.为了追溯Ghulkin冰川的活动历史和查明近期进退变化,对过去200 a的相关文献和记录进行统计分析,并开展了2008-2011年野外定点观测,总结与分析了Ghulkin冰川冰舌的活动历史与近期变化.研究表明：Ghulkin冰川在1885-1980年近百年间经历了3次前进和3次后退,在此期间冰川波动了625 m;1913-1925年冰川处于显著的前进状态,1966-1978年冰川有小段距离的前进;2008-2011年K676+660处泥石流沟道逐年抬升,2011年南坡冰川融水由K676+660改道至K676+450;2010年的南坡冰舌较1994年后退了300余米,2011年的南坡冰舌较2010年后退了15.066 m,可见在2010-2011年期间冰川处于局部短期后退状态. 中巴公路冰川泥石流等灾害不但受区域气候的影响,而且还受冰川变化的影响.未来气候变暖将会导致冰川的强烈消融和后退,冰川融水携带大量冰碛体,形成大型的冰川泥石流,对公路的安全运营造成严重威胁.     

On the performance of a new bivariate pseudo Pareto distribution with application to drought data

A new bivariate pseudo Pareto distribution is proposed, and its distributional characteristics are investigated. The parameters of this distribution are estimated by the moment-, the maximum likelihood- and the Bayesian method. Point estimators of the parameters are presented for different sample sizes. Asymptotic confidence intervals are constructed and the parameter modeling the dependency between two variables is checked. The performance of the different estimation methods is investigated by using the bootstrap method. A Markov Chain Monte Carlo simulation is conducted to estimate the Bayesian posterior distribution for different sample sizes. For illustrative purposes, a real set of drought data is investigated.